47309	----	EXPERIMENTS ON _THE NERVOUS SYSTEM_, WITH OPIUM AND METALLINE SUBSTANCES; MADE CHIEFLY WITH THE VIEW OF DETERMINING THE _NATURE AND EFFECTS_ OF ANIMAL ELECTRICITY. BY ALEXANDER MONRO, M. D. PROFESSOR OF MEDICINE, ANATOMY AND SURGERY IN THE UNIVERSITY OF EDINBURGH; FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS, AND OF THE ROYAL SOCIETY OF EDINBURGH, AND OF THE ROYAL ACADEMY OF SURGERY IN PARIS. EDINBURGH: PRINTED BY ADAM NEILL AND COMPANY, FOR BELL & BRADFUTE, AND T. DUNCAN; AND J. JOHNSON, LONDON. M.DCC.XCIII. CONTENTS. _Page_ INTRODUCTION, 5 Observations on the Circulating and Nervous Systems of Frogs, 6 Experiments with Opium, 9 Corollaries from the above Facts and Experiments, 12 Summary of Experiments made on Animals with Metalline Substances, 17 Summary of Facts proved by the foregoing Experiments, 35 Resemblance of the Fluid put in Motion by the foregoing Experiments to the Electrical Fluid, 38 The Nervous Fluid or Energy not the same with the Electrical, nor with the Fluid put in Motion by the foregoing Experiments, 40 General Conclusions, 42 INTRODUCTION. WHEN, in November last, I began to make Experiments on Animal Electricity, of which I read some account to the Royal Society on the 3d of December; I was not only much hurried with business, but could not procure a sufficient number of Frogs for the purpose. During the last winter and spring, I prosecuted the subject more fully and with greater attention; and, on the third day of June, I read a second paper to the Royal Society, to which I have, since that time, made additions. I shall now state a summary of the chief circumstances I have observed, with a few Remarks. OBSERVATIONS ON THE CIRCULATING AND NERVOUS SYSTEMS OF FROGS. AS my Experiments with Opium, as well as those on Animal Electricity, have been performed on Frogs chiefly; I shall premise some observations on their Circulating and Nervous Systems. THEIR Heart consists of one Auricle and one Ventricle only, their Aorta supplying their Air Vesicles or Lungs, as well as all their other Organs; and, of course, their Venæ Cavæ return the Blood from all parts to the Heart. The Ventricle of their Heart contracts about sixty times in a minute; and the purple colour of the Blood which is seen within it, disappears after each contraction, or the Blood is entirely expelled by its contraction. For upwards of an hour after cutting out its Heart, a Frog can crawl or jump; and, for upwards of half an hour longer, it contracts its Legs when the Toes are hurt, though not with sufficient force to more its Body from the place where it is laid. THEIR Encephalon consists of Brain and Cerebellum, each of which, on its upper part, is divided into two Hemispheres; and, below, they are conjoined by thick Crura, which form the Medulla Oblongata and Spinal Marrow, both of which are proportionally larger than in Man, and more evidently consist of two Cords. There are nine true Vertebræ; and at the sixth of these, the Spinal Marrow terminates in the Cauda Equina. The Sciatic Nerves are formed by three pairs of Nerves, sent out below the seventh, eighth and ninth Vertebræ, and by one pair from the Os Sacrum. A Nerve, resembling our great Sympathetic Nerve, passes downwards from the Abdomen into the Pelvis. TWO days after cutting off the Head of a Frog at its joining with the first Vertebra, I found it sitting with its Legs drawn up, in their usual posture; and when its Toes were hurt, it jumped with very considerable force. Its Heart likewise continued to beat about forty times in a minute, and so strongly as to empty itself and circulate the Blood. IN several Frogs, after cutting off the back part of the six undermost true Vertebræ, I took out all that part of the Spinal Marrow with the Cauda Equina which they cover. The lower Extremities were rendered insensible to common injuries, and lay motionless, yet the Frogs lived several months thereafter, and the wounded parts of their Backs cicatrised; and the Bones of their Legs, which I fractured, were re-united, the Blood circulating freely in their Vessels. IT is universally known, that if, after amputating the Limb of a warm blooded Animal, we repeatedly irritate the Nerves which terminate in Muscles, repeated Convulsions of the Muscles are for some time produced; and that in Frogs, and other cold blooded Animals, the Nerves retain this power still longer. BUT it has been commonly supposed, that, after irritating the Nerve a given number of times, the effect ceases, Authors conceiving that there is lodged in the Nerve some fluid, or other energy which is exhausted by repeated explosions. Instead of this, I have found that the time the Nerves preserve their power is the same, whether we irritate them or not; or that their energy is not exhausted by irritation, unless the irritation be such as sensibly alters their texture. EXPERIMENTS WITH OPIUM. I CUT one hole in the fore and upper part of the Cranium and Dura Mater of a Frog, and another in the back part of the lowermost Vertebræ, and then injected, from the one hole to the other, a small syringe full of water, in five ounces of which one ounce of Opium had been infused for three days. The infusion, by this means brought into contact with the whole surface of the Encephalon and Spinal Marrow, produced almost instantly universal convulsions; and, in less than two minutes thereafter, the Animal was incapable of moving its body from the place where it was laid. A quarter of an hour thereafter, I found the Heart beating twenty-five times only in the minute; and so feebly, that it could not entirely expel the Blood. When, half an hour thereafter, the Sciatic Nerves were pinched, a light tremor only was excited in the Muscles of the Leg; and Animal Electricity produced but feeble twitchings of the Muscles. THE infusion of Opium, injected in the same manner in Rabbits and in a Pig, produced similar effects. I HAD long ago[1] observed, that an infusion of Opium, poured into the Cavity of the Abdomen of a Frog, after cutting out its Heart, occasioned, in a few minutes, convulsions of its hind Legs. I have since found, that, after cutting off the Head, and cutting out the Heart of a Frog, its hind Legs are considerably weakened by pouring an infusion of Opium into the Cavity of its Abdomen. ALTHOUGH an infusion of Opium poured into the Auricle and Ventricle of the Heart of a Frog, instantly renders that Organ incapable of contraction, and, even after the Aorta has been previously cut, occasions convulsions of the Legs, yet I have not found that by Opium applied to the Brain, the Spinal Marrow, the Heart, or Abdominal Viscera, the Muscles of the Legs were so entirely killed as not to perform some motion when their Nerves were pinched, or when they were acted on by Animal Electricity. AFTER taking out the lower half of the Spinal Marrow, and likewise cutting transversely all the parts at the Pelvis, except the Crural Arteries and Veins and Lymphatics, which probably accompany them, I found that an infusion of Opium, applied to the Skin and Muscles of the Legs, affected the superior parts of the Body[2]: more probably, in my opinion, by absorption, than through any minute remanent branches of the Nerves, especially as I do not find, on laying the Vessels so prepared over a gold probe, and touching with it Zinc laid under the Spine, that convulsions of the Legs can be excited. At the same time, the quantity of Opium absorbed is so small, that I could not distinguish its smell or taste in the Blood; nor did I find these distinguishable, in other Experiments, in which the Frogs were violently convulsed after applying the infusion to the surface of their Skin. ANIMAL Electricity or different metals applied to the Head of a Frog, or to any part of its Spine above its sixth Vertebra, do not occasion convulsions of its hind Legs. COROLLARIES FROM THE ABOVE FACTS AND EXPERIMENTS. FROM the above Facts and Experiments, it appears, 1. THAT the Frog, after its Head is cut off, feels pain, and, in consequence of feeling, moves its Body and Limbs. 2. AS the Nerves of the hind Legs are not affected by Animal Electricity, unless it be applied lower than the fifth Vertebra, these Nerves do not seem to be derived solely or chiefly from the Brain or Cerebellum. 3. AS Opium, after the Circulation ceases, affects Organs distant from those to which it is applied, it is beyond doubt, that the latter suffer in consequence of Sympathy of Nerves. 4. IT appears that, in this Animal, there is Sympathy of Nerves after the Head is cut off; or that Sympathy of Nerves does not, in this Animal, depend entirely on the connection of Nerves within the Head. 5. AS, after cutting off the Head, this Animal is susceptible of pain, and, in consequence of that, performs voluntary motion, it appears that, in it, the Brain is not the sole seat of the _Sensorium Commune_. 6. SEVERAL weeks after I had taken out the lowermost half of the Spinal Marrow, and with it the Cauda Equina, I daily applied, for four days running, Animal Electricity to the Sciatic Nerves, by passing a gold Probe between them and the Os Sacrum, and excited several hundreds of convulsions of the Thighs and Legs, and yet found that, on laying bare the Femoral Nerves, and pinching them, the Muscles were slightly convulsed. HENCE, I apprehend, additional force is given to an opinion I ventured many years ago to propose[3], that the Nerves do not receive their energy wholly from the Head and Spinal Marrow, but that the texture of every branch of a Nerve is such as to furnish it, or that the structure of each Nerve is similar to that of the Brain. 7. FROM the above Experiments, it appears probable, in the highest degree, that Opium may be absorbed in such quantity as to produce fatal symptoms. 8. THE following circumstances concur in rendering inadmissible an opinion lately proposed by M. FONTANA, that Poisons operate by changes they produce on the mass of Blood, or on some unknown principle connected with the Blood. a. IF his opinion was just, Poison introduced into a Vein of the extremities, so as to be in contact with this unknown principle, should operate as quickly, and in the same manner as when the Poison is mixed with the Blood near the Heart, which he admits is not the case[4]. b. CUTTING the Spinal Marrow in Frogs, before applying the Poison of the Viper to their Legs, prevents it from killing them[5]; which should not happen, if the Poison acted on the Blood alone. c. HE acknowledges that an Animal bit in its Leg by a Viper, instantaneously feels acute pain[6]; and it, in like manner, feels instantly great uneasiness when the Poison is mixed with its Blood[7]. We know for certain, that, through the medium of the Nerves, we are instantly rendered sensible of injury done to the most distant parts of our Bodies. ARE we not, therefore, in the last mentioned Experiment, to conclude, that the uneasiness was produced because the Poison acted upon the Nerves of the Vessels? d. IN like manner, Animals were convulsed as soon as they were wounded, or received the Poison into a Blood-vessel; and long before the Blood could have reached the Muscles in action[8]. e. AS soon as the distilled Water of Lauro-cerasus was poured into the Stomach of a Pigeon, it was convulsed, died instantly[9], that is, before the Poison could have entered the Mass of Blood. f. MANY years ago, I found, after cutting the Venæ Cavæ and Aorta of a Frog, that a watery solution of Opium poured into the Heart, occasioned, in a few minutes, convulsions in its Legs; and, after cutting out the Heart, that the Opium poured into the Cavity of the Abdomen affected the Legs in like manner; although, in these Experiments, the Circulation was not only interrupted, but the greater part of the Blood evacuated. I THEREFORE then concluded[10], and now conclude, that Opium and other Poisons, even after they are mixed with the Mass of Blood, produce their fatal effects, chiefly and almost solely, by acting on the Nerves of the Heart and Vascular System, and, through these, affecting the whole of the Nervous System. SUMMARY OF EXPERIMENTS MADE ON ANIMALS WITH METALLINE SUBSTANCES. I SHALL now proceed to state the several circumstances I have observed, in my Experiments, which more directly lead us to judge of the Nature and Cause of Animal Electricity. 1. WHEN two Plates of different Metalline Substances, particularly of Zinc and Gold, between which a living Frog is placed, are brought into contact with each other, those Muscles, which are farther from the Brain and Spinal Marrow than the Metals, are convulsed: and this effect follows, although the Animal and Metals are placed on an inverted glass jar, and that a stick of sealing wax is interposed between the hand of the Operator and the Metals; that is, although the Animal, with the Metals, be insulated. I HAVE further observed, that the Metals, disposed as above described, excite convulsions in the Legs, after all the parts of the Frog have been divided transversely at the Pelvis, providing only that they are, thereafter, laid in contact with each other. 2. WHEN all the parts of a living Frog, except the large Nerves called Sciatic, are cut transversely at the Pelvis, and the fore part of the Animal is laid on a plate of Zinc, supported by glass, and the hind Legs on glass; if a gold Probe be applied so as to touch the Zinc and one of the Legs; or a piece of Metal put under one of the Legs; the Muscles of both Legs will be convulsed. THE event is the same, after the Body of the Frog has been cut transversely about the middle of the Spine: or when the Legs are laid on the Zinc and the Spine on Glass. IF a piece of perforated dry Paper is placed between the gold Probe and the Muscles, there will be no convulsions; but wet Paper interposed does not prevent the convulsions. ON separating the gold Probe from the Muscles there are no convulsions. 3. IF, after the Animal and Metals are placed as above described, the joining of the two Legs at the Ossa Pubis is cut, that Leg only will be convulsed with which the gold is in contact. 4. THE Spine of the Frog with the Zinc being placed on one glass, and the Legs on another glass, if the gold, supported by one hand, which we shall call the Right Hand, be applied to the Zinc alone, and not to the Legs, these are not convulsed. But if the Operator applies his left hand to the Legs, or if a bystander, communicating with the Operator by the medium of the floor only, touches them, they are convulsed. If a stick of sealing-wax be interposed between his right hand and the gold, or between his left hand and the Legs; or, if the bystander, touching the Legs, is insulated, by standing on a stool supported by glass feet, the Legs will not be convulsed. If the insulated bystander touches the Legs with one hand, and the Operator with his other hand, the Legs are immediately convulsed. 5. AFTER cutting the Spine transversely under the fifth Vertebra, and all the parts of the Pelvis, except the Sciatic Nerves, and laying the Spine on Zinc supported by glass, and the Legs on glass; if gold be applied to the Zinc, and then to one of the Sciatic Nerves, both Legs, if they have not been separated from each other at the Ossa Pubis, will be convulsed[11]. And this happens although a stick of sealing-wax be interposed between the hand of the Operator and the gold Probe, and although no Metalline Substance touches the Legs. THIS Experiment succeeds after denuding the Sciatic Nerves for the length of an inch, and wiping them dry; and it continues to succeed for an hour or more, and till the Nerves are evidently discoloured and shrunk in their size. And, after that, although we wet the Nerves, their powers are not restored; shewing that the influence had been conveyed not by wetness on the surface of the Nerves, but by the particular matter of which Nerves are composed. THE event is the same, when the upper ends of the Sciatic Nerves are cut away from the Spine, and laid on the Zinc. 6. AFTER preparing the Frog and placing the Metals as in last Experiment, if a piece of thin dry Paper, pierced with a number of small holes, be interposed between the gold Probe and the Sciatic Nerves, the Legs will not be convulsed. But, if the Paper be wetted, although it is not perforated, the Legs will be convulsed. AFTER preparing a Frog, as in last Experiment, and laying the Spine on one glass, and the Legs on another, if the Zinc be laid on a third glass, and the gold Probe applied to it and to the Sciatic Nerves, the Legs will not be convulsed. 8. IF the Spine and hind Legs, connected by the Sciatic Nerves, are all laid on the same plate of Zinc, supported by glass, the Legs are not convulsed on touching the Zinc with the gold Probe held in the right hand, although the left hand is applied to the Legs. 9. IF several Frogs, prepared as above described, are laid upon glass, in a straight line touching each other, and that the first Frog is supported on Zinc, and the last upon Gold; if one end of a brass wire is applied to the Zinc, and the other end of it to the Gold; the Muscles of all the Frogs will be convulsed. The event is the same, although a stick of sealing-wax be interposed between the hand of the Operator and the brass wire: that is, although the Frog with the Metals be insulated. 10. WHEN Frogs are prepared as in last Experiment, and the Spine of the first of them laid on Zinc, and the last supported by the left hand of the Operator, if with a gold Probe, held in his right hand, he touches the Zinc, the Muscles of all the Frogs will be convulsed. But if the hind Legs, as well as the Spine, of the first Frog be laid on the Zinc, the Muscles of that Frog will not be convulsed. 11. AFTER a Frog was prepared as before described, I cut the Sciatic Nerves where they are about to enter the Thighs, and laid their cut ends in contact with the Muscles, and then touched the Zinc and Nerves with a gold Probe, without exciting convulsions in the Thighs or Legs. 12. AFTER cutting the Sciatic Nerves, I tied together their divided parts, and then touched the Zinc and Nerves above the Ligature, with the Gold, without finding that the Legs were convulsed, when the Zinc supporting the Spine was laid on one glass and the Legs on another: but when the Metals and parts of the Frog were laid on a wet Table, the Muscles of the Leg were convulsed. 13. WHEN the Sciatic Nerves have been cut and rejoined by Ligature, if while the Gold is, with one hand, applied to the Zinc and Nerves, above the Ligature, the other hand touches the Feet, the Legs are convulsed. 14. IF the two hind Legs of a Frog are separated from each other, and their Sciatic Nerves afterwards tied to each other; if one of the Legs be laid on Zinc supported by glass, and the other Leg on glass, when, with one hand, the Toes of one of the Legs are touched, whilst with the other hand a gold Probe is applied to the Zinc and Nerve of the Leg which it supports, this Leg only will be convulsed. But if the gold Probe touching the Zinc be applied to the Nerve of the most distant Leg, both Legs will be convulsed. 15. I FOUND it was not necessary, in order to excite convulsions, that either of the Metals should be in contact with the living Nerve or living Flesh of the Frog; for if, after separating from each other the hind Legs of a Frog, and cutting transversely the upper part of their Sciatic Nerves, I laid a piece of putrid or boiled beef between their Sciatic Nerves, and two other pieces of putrid or boiled beef between their Toes and a plate of Zinc; if, with the point of a gold Probe, the side of which was applied to the piece of beef placed between the Sciatic Nerves, I touched the Zinc, both Legs were convulsed. 16. IN like manner, when I placed alternately, in a straight line, a number of dead and living Frogs touching each other, and in the living Frogs cut, at their Pelvis, all the parts but the Sciatic Nerves; if, with my left hand I touched a dead Frog at one end of the line, and with a gold Probe, held in my right hand, I touched a plate of Zinc, on which a dead Frog was laid at the other end of the line or chain of Frogs, the Muscles of all the living Frogs were convulsed. 17. WHEN a chain of living and dead Frogs was formed, as in the two last Experiments, but without cutting at their Pelvis all the parts but the Nerves; on applying the gold to the Zinc, convulsions of the Muscles were not excited. 18. IT has been found, that, if a plate of Zinc is applied to the upper part of the point of the Tongue, and a plate of Silver to its under part, on bringing the two Metals into contact with each other, a pungent disagreeable feeling, which it is difficult to describe, is produced in the point of the Tongue. And if a plate of Zinc is placed between the upper lip and the gums, and a plate of gold applied to the upper or under part of the Tongue, on bringing these two Metals into contact with each other, the person imagines that he sees a flash of lightning, which, however, a bystander in a dark room does not perceive; and the person performing the Experiment perceives the flash, though he is hoodwinked. IT has been alleged, that the Flash happens before the two Metals touch each other, and is repeated on separating them; but these facts appear to me very doubtful, as I do not find that a Flash is produced when a piece of Cambric-paper, in which a number of holes is pierced with a pin, is interposed between the Zinc and Silver, although the Paper does not in thickness exceed 1/1500 part of an inch. AFTER performing this Experiment repeatedly, I constantly felt a pain in my upper jaw at the place to which the Zinc had been applied, which continued for an hour or more: And in one Experiment after I had applied a blunt Probe of Zinc to the Septum Narium, and repeatedly touched with it a Crown piece of Silver applied to the Tongue, and thereby produced the appearance of a Flash, several drops of Blood fell from that Nostril; and Dr FOWLER, after making such an Experiment on his Ears, observed a similar effect[12]. I HAVE farther observed, that although the previous application of a second plate of Silver to one half of the plate of Zinc, does not prevent the Flash when the other half of the plate of Zinc, touching the Tongue, is brought into contact with the first piece of Silver placed between the lip and the gum; yet if the Zinc and Silver are in the first place applied to each other, then placed between the lip and gum, and, after this, touched with the Tongue, there is no appearance of a Flash, although some degree of pungency and a disagreeable sensation is perceived by the Tongue: and a mixed mass, composed of one part of Zinc and two parts of Quicksilver, or a mass composed of three parts of Zinc and one of Silver, incorporated in a furnace, have not the effect, when they are applied to Nerves, of exciting convulsions of the Muscles in which the Nerves terminate. I HAVE also found, that two thick pieces of raw or boiled flesh, one between the Zinc and Tongue, and the other between the Silver and Tongue, do not prevent the disagreeable pungent sensation when the two Metals touch: and, in like manner, that the interpolation of two pieces of flesh between the Zinc and Tongue, and between the Silver and the upper Lip, does not prevent the appearance of a flash, on bringing the two Metals into contact. 19. I PUT a very thick plate of Zinc into a vessel with water, and placed, near to it, in the water, the under part of the Spine and the hind Legs of a Frog, after cutting all the parts at the Pelvis except the Sciatic Nerves. I then touched the Zinc with a gold Probe, and found, that, when I touched that part of the Zinc which was above the water, the Legs of the Frog were not affected; but when I touched that part of the Zinc which was below the surface of the water, the Legs of the Frog were convulsed[13]. I NEXT put into the water one of the hind Legs of a dead Frog, and its other Leg into an adjoining vessel with water. Into the opposite side of the second vessel, I put one of the hind Legs of a living Frog, in which all the parts at the Pelvis, except the Sciatic Nerves, were cut; and into a third glass vessel with water, I put its other Leg. When I now touched that part of the Zinc, which was below the surface of the water with a gold Probe, the Legs were not convulsed; but, if I, at the same time, dipped the finger of my other hand into the water contained in the third vessel, they were convulsed: when, instead of my finger, I dipped into the water a stick of sealing-wax, held in my other hand, the Legs were not convulsed. I FOUND, by the three following Experiments, that the Muscles are convulsed, whether the Influence, produced by the application of the Metals, passes upwards or downwards along the Nerves. 20. I CUT four living Frogs transversely at the middle part of their Spines, and threw away the fore parts of their Bodies and their Abdominal Viscera. I NEXT cut, at their _Pelves_ all the Parts but the Sciatic Nerves; and at their Knees, I cut all the Parts but the Crural Nerves; and, in all of them, I cut asunder the joining of the two hind Legs at their Ossa Pubis. I then laid the Legs of all of them in a straight line, supported on different Glass Vessels inverted, in such a manner that the Foot of one Frog touched the Foot of the next to it. HAVING then placed a Plate of Zinc under the Foot of the first Frog, and holding in my left hand the Foot of the fourth or last Frog, I touched the Zinc with a gold Probe which I held in my right hand; and found that all the Muscles of the Loins, Thighs and Legs of the four Frogs were convulsed. 21. WHEN I placed the two Frogs in the middle, with their Spines contiguous to each other, and the Feet of both touching the Spines of the other two Frogs forming the Extremities of the Chain, and of course the Feet of one of these resting on the Zinc, and the Feet of the other supported by my left hand: On touching the Zinc with the gold Probe held in my right hand, all the Muscles of the Frogs were, as before, convulsed. 22. WHEN I now turned aside the right Legs of all the Frogs, so that they did not form a Chain by touching the next Frogs; the right Legs were not convulsed. IT is evident, that in whatever direction we suppose the influence to have passed in its Circle, it must, in Experiment 20th, have passed up one Leg and down the other in the same Frog: And, in Experiment 21st, if it passed from one end of the Chain to the other end of it, it must have passed upwards in two of the Frogs, and downwards in the other two; or if the influence passed from the two ends of the Chain towards its middle, where the Spines of the two middlemost Frogs were contiguous, it must have passed upwards in all of them. 23. WHEN after cutting four living Frogs transversely at the middle of their Spines, but without cutting at their Pelves all the Parts but the Sciatic Nerves, I placed the hind Parts of them in a Chain, as in Experiments 20th, 21st and 22d, the Muscles were not convulsed on applying the Gold to the Zinc. I NEXT found, that after placing in contact with each other the several Muscles which had been cut transversely in Experiments 20th, 21st and 22d, allowing the Nerves to remain undivided, the muscles were not convulsed when I touched the Plate of Zinc with the gold Probe held in my right hand, although I touched the other end of the Chain of Frogs with my left hand. THE reason why the Muscles were convulsed in Experiments 20th, 21st and 22d, and not in Experiment 23d, evidently is, that in the former, the influence was concentrated in the Nerve, in the latter the influence was diffused; that is, was in part conveyed by other Organs, as well as by the Trunks of the Nerves. 24. AFTER finding that I could readily excite Convulsions in the hind Legs of a Frog, without cutting it, by laying its Back on a Plate of Zinc, and introducing a gold Probe within its Intestinum Rectum and touching the Zinc with the side of the Probe, I produced two or three hundred Convulsions, succeeding each other quickly, and observed that its Legs were, by these means, so much weakened, that it could not jump, and crawled with difficulty, but in a few minutes it recovered nearly the full force of its Muscles. IN other Frogs I passed a gold Wire between their Sciatic Nerves and Os Sacrum, and twisted together the two ends of the Wire over the Backs of the Animals. I then put them into a Zinc Vessel filled with Water, or into a Glass Vessel filled with Water, in the bottom of which I laid a large Plate of Zinc: So that every time the Animals by moving separated the Gold from the Zinc, and again brought them into contact, their hind Legs were convulsed. I allowed them to remain three or four days in this situation, and found that their Limbs were weakened considerably, but not exhausted of their Power of Motion; and, after removing the gold Wire, the Limbs by degrees recovered their strength. I MADE the same Experiment on those Frogs in which I had, six weeks before, cut out, from behind, all that part of their Spinal Marrow which is covered by the six undermost Vertebræ, and found, several days after the Frogs had been subjected to the Experiment, that, by pinching their Sciatic and Femoral Nerves, and still more readily by the application of the Gold and Zinc, weak convulsions of the Muscles were excited. 25. AFTER Frogs were prepared as above described, by cutting their Spines transversely, and then all the parts of their Pelves, except their Sciatic Nerves, I found that slight Electrical Shocks, or a Leyden Phial discharged directly through the Limbs of a Frog, or indirectly by the medium of water, produced convulsions in their Muscles, exactly resembling those excited by the Metals. And when, after moderate Electrical Shocks had been passed repeatedly through their Legs, the Metals were applied to their Nerves, in the manner before mentioned, the Muscles were convulsed. I found, likewise, that after cutting the Nerves transversely, and tying them together, Electrical Shocks were conducted by the Nerves, and occasioned convulsions of the Muscles. WHEN I had killed Frogs, by discharging through them, from their foreheads to their hind feet, large Leyden Phials highly charged, I found their Nerves or Muscles, or both, so much deranged, that feeble convulsions only could be excited by pinching the Nerves, or by applying the Metals to them. SUMMARY OF FACTS PROVED BY THE FOREGOING EXPERIMENTS. ON reviewing the foregoing Experiments, we shall find the following Facts fully proved. 1. ON forming a Circle by means of the parts of a living Animal and of two different metallic Bodies, especially Gold and Zinc, in contact with each other, if a Nerve makes part of the Circle, the Muscles in which the Nerve terminates are convulsed. 2. ALTHOUGH the Nerve making part of such a Circle has been cut transversely, yet, if the divided parts of the Nerve are laid in contact with each other, or tied together, the Muscles, in which it naturally terminates, are convulsed. 3. IF the Metals, composing parts of the Circle, are kept steadily in contact with each other, the convulsions of the Muscles cease. But, if they are separated from each other and again rejoined, the convulsions are repeated. 4. THE effects are the same, although the dead parts of an Animal or pure water make parts of the Circle. 5. ALTHOUGH the dead parts of an Animal, making part of such a Circle, are in contact with the Metals, the effects are the same. 6. A MUSCLE making part of such a Circle may be convulsed whilst the matter put in motion is passing in the direction from the Muscle to the Nerve. 7. THE Muscle may be convulsed although it makes no part of the Circle in which the matter put in motion passes, as appears from comparing Experiment 5th with Experiments 13th and 14th. From Experiment 13th, it appears, that the Fluid put in Motion by the Metals passes readily along a Nerve, after it has been cut, providing the divided Parts of it are brought into contact with each other. Yet in Experiment 14th, in which the left hand of the Operator was not applied to the Foot of the Frog, the Muscles in which the Nerve, lower than the Ligature, terminated, were not convulsed, because the Fluid put in motion did not descend lower than the place at which the gold Probe touched the Nerve above the Ligature. We may therefore presume that when a Nerve which has not been cut, as in Experiment 5th, is touched with the gold Probe, the Fluid put in motion does not pass lower in the Nerve than the place of the Probe. Hence we perceive the error of those who suppose that the moisture on the surface of the Nerve conduces the Fluid put in motion to the Muscles, and that their action is in consequence of the direct operation of this Fluid upon their Fibres. 8. THE effects are the same when the Animal and the Metals are insulated, by being placed on Glass, whilst Sealing-wax is interposed between the hand of the Operator and the Metals. 9. IF any part of the Circle is composed of Sealing-wax or Glass, the Muscles are not convulsed. 10. CONVULSIONS are not excited unless the Metals are in contact with each other; and unless both Metals are also in contact with the Animal Substances or the Water making part of the Circle. RESEMBLANCE OF THE FLUID PUT IN MOTION BY THE FOREGOING EXPERIMENTS TO THE ELECTRICAL FLUID. THE Fluid set in motion by the application of the Metals to each other, and to Animal Bodies or to Water, agrees with or resembles the Electrical Fluid in the following respects. LIKE the Electrical Fluid, it communicates the sense of pungency to the Tongue. LIKE the Electrical Fluid, it is conveyed readily by Water, Blood, the Bodies of Animals, the Metals; and is arrested in its course by Glass, Sealing-Wax, _&c._ IT passes, with similar rapidity, through the Bodies of Animals. LIKE the Electrical Fluid, it excites the activity of the Vessels of a living Animal, as the Pain it gives and Hemorrhagy it produces seem to prove. Hence perhaps it might be employed with advantage in Amenorrhoea. IT excites Convulsions of the Muscles in the same manner, and with the same effects as Electricity. WHEN the Metals and Animal are kept steadily in contact with each other, the Convulsions cease, or an Equilibrium seems to be produced, as after discharging a Leyden Phial. THE NERVOUS FLUID OR ENERGY NOT THE SAME WITH THE ELECTRICAL NOR WITH THE FLUID PUT IN MOTION BY THE FOREGOING EXPERIMENTS. THAT the Nervous Fluid is the same with the Electrical, or with the Fluid which is put in motion by the foregoing Experiments, is, I apprehend, disproved by the following circumstances. 1. WITHOUT stating the difficulty there is in conceiving how the Electrical Fluid can be accumulated by or confined within our Nervous System, we may observe that where the Electrical Fluid, or Fluid resembling that put in motion by the foregoing Experiments, is accumulated by an Animal, such as the Torpedo or Gymnotus, a proper apparatus is given to the Animal, by means of which it is enabled to collect and to discharge this Fluid. 2. THE Nervous Power is excited by chemical or by mechanical Stimuli; and, on the other hand, is destroyed by Opium and other Poisons, which cannot be imagined to act on the Electrical Fluid. 3. I HAVE, I apprehend, refuted the theory of Doctors GALVANI, VALLI and others, which supposes that the Nerve is electrified _plus_ and the Muscle _minus_, resembling the Leyden Phial, by shewing that the Muscles are convulsed where there is no communication between them and the Metals, but by the medium of the Nerve; or when the Metals are applied to different parts of the Nerve alone, without touching the Muscles which are convulsed, and when the Muscle which is convulsed makes no part of the Circle in which the Matter that is put in motion passes. 4. I HAVE proved, that the Muscles are convulsed whilst the current of the Electrical Matter is passing from them and from the smaller Branches of the Nerves into their Trunks; and as a Muscle is never thrown into Action by the Nervous Energy, except when this passes from the Trunk of the Nerve into its Branches, and from these into the Muscle, it appears that when, in these Experiments, the Muscles were convulsed, the Nervous and the Electrical Fluids were moving in opposite Directions; from which we may infer, that, in their Nature, they differ essentially from each other. 5. THE Nervous Energy is stopped by a tight Ligature or by the transverse Incision of a Nerve, although its divided Parts are thereafter placed in contact with each other; whereas the Electrical Fluid or the Fluid excited by the Metals, passes readily, downwards or upwards, along a Nerve which has been tied or cut. 6. AFTER the Limb of a living Animal has been amputated, frequent Convulsions of the same Muscles may be excited by applying Mechanical or Chemical Stimuli to its Nerves; whereas Electrical Matter discharges itself suddenly. HENCE I conclude, 1. THAT the Fluid, which, on the application of Metalline Bodies to Animals, occasions Convulsions of their Muscles, is electrical, or resembles greatly the Electrical Fluid. 2. THAT this Fluid does not operate directly on the Muscular Fibres, but merely by the Medium of their Nerves. 3. THAT this Fluid and the Nervous Fluid or Energy are not the same, but differ essentially in their Nature. 4. THAT this Fluid acts merely as a Stimulus to the Nervous Fluid or Energy. 5. THAT these Experiments have merely shown a new mode of exciting the Nervous Fluid or Energy, without throwing any farther or direct Light on the nature of this Fluid or Energy. FINIS. FOOTNOTES: [1] See Edin. Phys. Ess. Vol. III. [2] See Edin. Phys. Ess. Vol. III. [3] See Observations on the Nervous System, 1783, Chap. x. and xi. [4] See FONTANA sur les Poisons, 1781, p. 267. [5] See FONTANA, p. 293. [6] FONTANA, p. 244. [7] FONTANA, p. 259. [8] FONTANA, p. 112. p. 259. [9] FONTANA, p. 142. [10] Edin. Phys. Ess. published in 1771, p. 363. [11] Very small portions of different metals, applied as above described, have astonishing effects; and although I have found that large portions of the metals produced convulsions, when smaller had failed, or that they produced stronger convulsions; yet the effects are by no means proportioned to the weight of the metals employed, nor to the extent of their surfaces which are suddenly brought into contact. In most of my Experiments, I employed a plate of Zinc, about five inches long, three inches broad, and about one-third of an inch thick; and a gold Probe, somewhat thicker and longer than the Probes Surgeons commonly use. [12] See Dr FOWLER'S Book, p. 85. [13] After reading to the Royal Society, on the 3d of June, an account of this Experiment, which I had made in the beginning of May, I found, from an ingenious publication of my Pupil Dr FOWLER, which I received that evening, that the same Experiment had been performed by him. TRANSCRIBER'S NOTE: --Obvious print and punctuation errors were corrected. 
51132	----	Whiskaboom By ALAN ARKIN Illustrated by DIEHL [Transcriber's Note: This etext was produced from Galaxy Science Fiction August 1955. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] Jack's blunder was disastrous, but what he worried about was: would Einstein have approved? Dear Mr. Gretch: Mrs. Burroughs and I are sending your son Jack to you because we do not know what else to do with him. As you can see, we can't keep him with us in his present condition. Also, Jack owes us two weeks rent and, since Mrs. Burroughs and I are retired, we would appreciate your sending the money. It has been a dry year and our garden has done poorly. The only reason we put up with your son in the first place was because we are so hard-pressed. He saw the sign on the porch, rang the bell and paid Mrs. Burroughs a month's rent without even looking at the room. Then he ran out to his car and commenced pulling out suitcases and boxes and dragging them upstairs. After the third trip, Mrs. Burroughs saw he was having trouble with the stuff and he looked kind of worn out, so she offered to help. He gave her a hard look, as she described it to me when I got home. He said, "I don't want anyone touching anything. Please don't interfere." "I didn't mean to interfere," my wife told him. "I only wanted to help." "I don't want any help," he said quietly, but with a wild look in his eye, and he staggered upstairs with the last of his baggage and locked the door. * * * * * When I got home, Mrs. Burroughs told me she thought I ought to take a look at the new boarder. I went up, thinking we'd have a little chat and straighten things out. I could hear him inside, hammering on something. He didn't hear my first knock or the second. I got sore and nearly banged the door down, at which time he decided to open up. I charged in, ready to fight a bear. And there was this skinny red-headed son of yours glaring at me. "That's a lot of hammering you're doing, son," I said. "That's the only way I can get these boxes open, and don't call me son." "I don't like to disturb you, Mr. Gretch, but Mrs. Burroughs is a little upset over the way you acted today. I think you ought to come down for a cup of tea and get acquainted." "I know I was rude," he said, looking a little ashamed, "but I have waited for years for a chance to get to work on my own, with no interference. I'll come down tomorrow, when I have got my equipment set up, and apologize to Mrs. Burroughs then." I asked him what he was working on, but he said he would explain later. Before I got out of the door, he was hammering again. He worked till after midnight. We saw Jack at mealtimes for the next few days, but he didn't talk much. We learned that he was twenty-six, in spite of his looking like a boy in his teens, that he thought Prof. Einstein the greatest man ever, and that he disliked being called son. Of his experiment, he didn't have much to say then. He saw Mrs. Burroughs was a little nervous about his experimenting in the guest room and he assured her it was not dangerous. Before the week was out, we started hearing the noises. The first one was like a wire brush going around a barrel. It went _whisk, whisk_. Then he rigged up something that went _skaboom_ every few seconds, like a loud heartbeat. Once in a while, he got in a sound like a creaky well pump, but mostly it was _skaboom_ and _whisk_, which eventually settled down to a steady rhythm, _whiskaboom, whiskaboom_. It was kind of pleasant. * * * * * Neither of us saw him for two days. The noises kept going on. Mrs. Burroughs was alarmed because he did not answer her knock at mealtimes, and one morning she charged upstairs and hollered at him through the door. "You stop your nonsense this minute and come down to breakfast!" "I'm not hungry," he called back. "You open this door!" she ordered and, by George, he did. "Your _whiskaboom_ or whatever it is will keep till after breakfast." He sat at the table, but he was a tired boy. He had a cold, his eyelids kept batting, and I don't believe he could have lifted his coffee cup. He tried to look awake, and then over he went with his face in the oatmeal. Mrs. Burroughs ran for the ammonia, but he was out cold, so we wiped the oatmeal off his face and carried him upstairs. My wife rubbed Jack's wrists with garlic and put wet towels on his face, and presently he came to. He looked wildly about the room at his machinery. It was all there, and strange-looking stuff, too. "Please go away," he begged. "I've got work to do." Mrs. Burroughs helped him blow his nose. "There'll be no work for you, sonny. Not until you're well. We'll take care of you." He didn't seem to mind being called sonny. He was sick for a week and we tended him like one of our own. We got to know him pretty well. And we also got to know you. Now, Mr. Gretch, whatever you are doing in your laboratory is your own business. You could be making atomic disintegrators, for all Jack told us. But he does not like or approve of it and he told us about your running battle with him to keep him working on your project instead of his own. Jack tried to explain his ideas for harnessing time and what he called "the re-integration principle." It was all so much _whiskaboom_ to us, so to speak, but he claimed it was for the good of mankind, which was fine with us. But he said you would not let him work it out because there was less money in it than in your project, and this is why he had to get away and work and worry himself into a collapse. When he got well, Mrs. Burroughs told him, "From now on, you're going to have three meals a day and eight hours sleep, and in between you can play on your _whiskaboom_ all you please." The _whiskabooming_ became as familiar to us as our own voices. Last Sunday, Mrs. Burroughs and I came home from church, about noon. She went inside through the front door to fix dinner. I walked around the house to look at the garden. And the moment I walked past the front of the house, I got the shock of my life. The house disappeared! * * * * * I was too surprised to stop walking, and a step later I was standing at the back of the house, and it was all there. I took a step back and the whole house vanished again. One more step and I was at the front. It looked like a real house in front and in back, but there wasn't any in-between. It was like one of those false-front saloons on a movie lot, but thinner. I thought of my wife, who had gone into the kitchen and, for all I knew, was as thin as the house, and I went charging in the back door, yelling. "Are you all right?" "Of course I'm all right," she said. "What's the matter with you?" I grabbed her and she was all there, thank heavens. She giggled and called me an old fool, but I dragged her outside and showed her what had happened to our house. She saw it, too, so I knew I didn't have sunstroke, but she couldn't understand it any better than I. Right about then, I detected a prominent absence of _whiskabooming_. "Jack!" I hollered, and we hurried back into the house and upstairs. Well, Mr. Gretch, it was so pitiful, I can't describe it. He was there, but I never saw a more miserable human being. He was not only thin but also flat, like a cartoon of a man who had been steamrollered. He was lying on the bed, holding onto the covers, with no more substance to him than a thin piece of paper. Less. Mrs. Burroughs took one of his shoulders between her thumb and forefinger, and I took the other, and we held him up. There was a breeze coming through the window and Jack--well, he waved in the breeze. We closed the window and laid him down again and he tried to explain what had happened. "Professor Einstein wouldn't have liked this!" he moaned. "Something went wrong," he cried, shuddering. He went on gasping and mumbling, and we gathered that he had hooked up a circuit the wrong way. "I didn't harness the fourth--I chopped off the third dimension! Einstein wouldn't have approved!" He was relieved to learn that the damage had been confined to himself and the house, so far as we knew. Like the house, Jack had insides, but we don't know where they are. We poured tea down him, and he can eat, after a fashion, but there never is a sign of a lump anywhere. * * * * * That night, we pinned him to the bed with clothespins so he wouldn't blow off the bed. Next morning, we rigged a line and pinned him to it so he could sit up. "I know what to do," he said, "but I would have to go back to the lab. Dad would have to let me have his staff and all sorts of equipment. And he won't do it." "If he thinks more of his money than he does of his own son," Mrs. Burroughs said, "then he's an unnatural father." But Jack made us promise not to get in touch with you. Still, people are beginning to talk. The man from the electric company couldn't find the meter yesterday, because it is attached to the middle of the outside wall and has vanished. Mr. Gretch, we are parents and we feel that you will not hesitate a moment to do whatever is necessary to get Jack back into shape. So, despite our promise, we are sending Jack to you by registered parcel post, air mail. He doesn't mind the cardboard mailing tube he is rolled up in as he has been sleeping in it, finding it more comfortable than being pinned to the sheets. Jack is a fine boy, sir, and we hope to hear soon that he is back to normal and doing the work he wants to do. Very truly yours, W. Burroughs P.S. When Jack figures out the re-integration principle, we would appreciate his fixing our house. We get along as usual, but it makes us nervous to live in a house that, strictly speaking, has no insides. W.B. 
51397	----	PEOPLE SOUP By ALAN ARKIN Illustrated by JOHNSON [Transcriber's Note: This etext was produced from Galaxy Magazine November 1958. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] When you took pot luck with this kitchen scientist, not even the poor pot was lucky! Bonnie came home from school and found her brother in the kitchen, doing something important at the sink. She knew it was important because he was making a mess and talking to himself. The sink drain was loaded down with open soda bottles, a sack of flour, corn meal, dog biscuits, molasses, Bromo-Seltzer, a tin of sardines and a box of soap chips. The floor was covered with drippings and every cupboard in the kitchen was open. At the moment, Bonnie's brother was putting all his energy into shaking a plastic juicer that was half-filled with an ominous-looking, frothy mixture. Bonnie waited for a moment, keeping well out of range, and then said, "Hi, Bob." "Lo," he answered, without looking up. "Where's Mom?" "Shopping." Bonnie inched a little closer. "What are you doing, Bob?" she asked. "Nothing." "Can I watch?" "No." Bonnie took this as a cue to advance two cautious steps. She knew from experience how close she could approach her brother when he was being creative and still maintain a peaceful neutrality. Bob slopped a cupful of ketchup into the juicer, added a can of powdered mustard, a drop of milk, six aspirin and a piece of chewing gum, being careful to spill a part of each package used. Bonnie moved in a bit closer. "Are you making another experiment?" she asked. "Who wants to know?" Bob answered, in his mad-scientist voice, as he swaggered over to the refrigerator and took out an egg, some old bacon fat, a capsuled vitamin pill, yesterday's Jello and a bottle of clam juice. "Me wants to know," said Bonnie, picking up an apple that had rolled out of the refrigerator and fallen on the floor. "Why should I tell you?" "I have a quarter." "Where'd you get it?" "Mom gave it to me." "If you give it to me, I'll tell you what I'm doing." "It's not worth it." "I'll let you be my assistant, too." "Still not worth it." "For ten cents?" "Okay, ten cents." * * * * * She counted out the money to her brother and put on an apron. "What should I do now, Bob?" "Get the salt," Bob instructed. He poured sardine oil from the can into the juicer, being very careful not to let the sardines fall in. When he had squeezed the last drop of oil out of the can, he ate all the sardines and tossed the can into the sink. Bonnie went after the salt and, when she lifted out the box, she found a package containing two chocolate graham crackers. "Mom has a new hiding place, Bob," she announced. Bob looked up. "Where is it?" "Behind the salt." "What did you find there?" "Two chocolate grahams." Bobby held out his hand, accepted one of the crackers without thanks and proceeded to crumble the whole thing into his concoction, not even stopping to lick the chocolate off his hands. Bonnie frowned in disbelief. She had never seen such self-sacrifice. The act made her aware, for the first time, of the immense significance of the experiment. She dropped her quarrel completely and walked over to the sink to get a good look at what was being done. All she saw in the sink was a wadded, wet Corn Flake box, the empty sardine tin and spillings from the juicer, which by this time was beginning to take on a distinctive and unpleasant odor. Bob gave Bonnie the job of adding seven pinches of salt and some cocoa to the concoction. "What's it going to be, Bob?" she asked, blending the cocoa on her hands into her yellow corduroy skirt. "Stuff," Bob answered, unbending a little. "Government stuff?" "Nope." "Spaceship stuff?" "Nope." "Medicine?" "Nope." "I give up." "It's animal serum," Bob said, sliced his thumb on the sardine can, glanced unemotionally at the cut, ignored it. "What's animal serum, Bob?" "It's certain properties without which the universe in eternity regards for human beings." "Oh," Bonnie said. She took off her apron and sat down at the other end of the kitchen. The smell from the juicer was beginning to reach her stomach. Bobby combed the kitchen for something else to throw into his concoction and came up with some oregano and liquid garlic. "I guess this is about it," he said. He poured the garlic and oregano into his juicer, put the lid on, shook it furiously for a minute and then emptied the contents into a deep pot. "What are you doing now, Bob?" Bonnie asked. "You have to cook it for seven minutes." * * * * * Bobby lit the stove, put a cover on the pot, set the timer for ten minutes and left the room. Bonnie tagged after him and the two of them got involved in a rough game of basketball in the living room. "BING!" said the timer. Bob dropped the basketball on Bonnie's head and ran back into the kitchen. "It's all done," he said, and took the cover off the pot. Only his dedication to his work kept him from showing the discomfort he felt with the smell that the pot gave forth. "Fyew!" said Bonnie. "What do we do with it now? Throw it out?" "No, stupid. We have to stir it till it cools and then drink it." "Drink it?" Bonnie wrinkled her nose. "How come we have to drink it?" Bobby said, "Because that's what you do with experiments, stupid." "But, Bob, it smells like garbage." "Medicine smells worse and it makes you healthy," Bob said, while stirring the pot with an old wooden spoon. Bonnie held her nose, stood on tiptoe and looked in at the cooking solution. "Will this make us healthy?" "Maybe." Bob kept stirring. "What will it do?" "You'll see." Bob took two clean dish towels, draped them around the pot and carried it over to the formica kitchen table. In the process, he managed to dip both towels in the mixture and burn his already sliced thumb. One plastic handle of the pot was still smoldering, from being too near the fire, but none of these things seemed to have the slightest effect on him. He put the pot down in the middle of the table and stared at it, chin in hand. Bonnie plopped down opposite him, put her chin in her hands and asked, "We _have_ to drink that stuff?" "Yup." "Who has to drink it first?" Bob made no sign of having heard. "I thought so," said Bonnie. Still no comment. "What if it kills me?" Bobby spoke by raising his whole head and keeping his jaw stationary in his hands. "How can it hurt you? There's nothing but pure food in there." Bonnie also sat and stared. "How much of that stuff do I have to drink?" "Just a little bit. Stick one finger in it and lick it off." Bonnie pointed a cautious finger at the tarry-looking brew and slowly immersed it, until it barely covered the nail. "Is that enough?" "Plenty," said Bob in a judicious tone. Bonnie took her finger out of the pot and stared at it for a moment. "What if I get sick?" "You can't get sick. There's aspirin and vitamins in it, too." Bonnie sighed and wrinkled her nose. "Well, here goes," she said. She licked off a little bit. Bob watched her with his television version of a scientific look. "How do you feel?" he inquired. Bonnie answered, "It's not so bad, once it goes down. You can taste the chocolate graham cracker." Bonnie was really enjoying the attention. "Hey," she said, "I'm starting to get a funny feeling in my--" and, before she could finish the sentence, there was a loud _pop_. Bob's face registered extreme disappointment. She sat quite still for a moment and then said, "What happened?" "You've turned into a chicken." * * * * * The little bird lifted its wings and looked down at itself. "How come I'm a chicken, Bob?" it said, cocking its head to one side and staring at him with its left eye. "Ah, nuts," he explained. "I expected you to be more of a pigeon thing." Bob mulled over the ingredients of his stew to see what went wrong. The chicken hopped around the chair on one leg, flapped its wings experimentally and found itself on the kitchen table. It walked to the far corner and peered into a small mirror that hung on the side of the sink cabinet. "I'm a pretty ugly chicken, boy," it said. It inspected itself with its other eye and, finding no improvement, walked back to Bobby. "I don't like to be a chicken, Bob," it said. "Why not? What does it feel like?" "It feels skinny and I can't see so good." "How else does it feel?" "That's all how it feels. Make me stop being it." "First tell me better what it's like." "I told you already. Make me stop being it." "What are you afraid of? Why don't you see what it's like first, before you change back? This is a valuable experience." The chicken tried to put its hands on its hips, but could find neither hips nor hands. "You better change me back, boy," it said, and gave Bob the left-eye glare. "Will you stop being stupid and just see what it's like first?" Bob was finding it difficult to understand her lack of curiosity. "Wait till Mom sees what an ugly mess I am, boy. Will you ever get it!" Bonnie was trying very hard to see Bob with both eyes at once, which was impossible. "You're a sissy, Bonnie. You ruined the opportunity of a lifetime. I'm disgusted with you." Bob dipped his forefinger in the serum and held it toward the chicken. It pecked what it could from the finger and tilted its head back. In an instant, the chicken was gone and Bonnie was back. She climbed down from the table, wiped her eyes and said, "It's a good thing you fixed me, boy. Would you ever have got it." "Ah, you're nothing but a sissy," Bob said, and licked off a whole fingerful of his formula. "If I change into a horse, I won't let you ride me, and if I change into a leopard, I'll bite your head off." Once again, the loud _pop_ was heard. * * * * * Bonnie stood up, wide-eyed. "Oh, Bob," she said, "you're beautiful!" "What am I?" Bob asked. "You're a bee-yoo-tee-full St. Bernard, Bob! Let's go show Melissa and Chuck." "A St. Bernard?" The animal looked disgusted. "I don't want to be no dog. I want to be a leopard." "But you're _beautiful_, Bob! Go look in the mirror." "Naah." The dog paddled over to the table. "What are you going to do, Bob?" "I'm going to try it again." The dog put its front paws on the table, knocked over the serum and lapped up some as it dripped on the floor. _Pop_ went the serum, taking effect. Bobby remained on all fours and kept on lapping. _Pop_ went the serum again. "What am I now?" he asked. "You're still a St. Bernard," said Bonnie. "The devil with it then," said the dog. "Let's forget all about it." The dog took one last lap of serum. _Pop!_ Bobby got up from the floor and dejectedly started out the back door. Bonnie skipped after him. "What'll we do now, Bob?" she asked. "We'll go down to Thrifty's and get some ice cream." They walked down the hill silently, Bobby brooding over not having been a leopard and Bonnie wishing he had stayed a St. Bernard. As they approached the main street of the small town, Bonnie turned to her brother. "You want to make some more of that stuff tomorrow?" "Not the same stuff," said Bob. "What'll we make instead?" "I ain't decided yet." "You want to make an atomic bomb?" "Maybe." "Can we do it in the juicer?" "Sure," Bob said, "only we'll have to get a couple of onions." 
51751	----	OH, RATS! By MIRIAM ALLEN DEFORD Illustrated by WOOD [Transcriber's Note: This etext was produced from Galaxy Magazine December 1961. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] Orthedrin, maxiton and glutamic acid--they were the prescription that made him king of his world! SK540, the 27th son of two very ordinary white laboratory rats, surveyed his world. He was no more able than any other rat to possess articulate speech, or to use his paws as hands. All he had was a brain which, relative to its size, was superior to any rat's that had hitherto appeared on Earth. It was enough. In the first week of gestation his embryo had been removed to a more suitable receptacle than the maternal womb, and his brain had been stimulated with orthedrin, maxiton and glutamic acid. It had been continuously irrigated with blood. One hemisphere had been activated far in excess of the other, since previous experiments had shown that increased lack of symmetry between the hemispheres produced superior mentality. The end-result was an enormous increase in brain-cells in both hemispheres. His brain showed also a marked increase in cholinesterase over that of other rats. SK540, in other words, was a super-rat. The same processes had been applied to all his brothers and sisters. Most of them had died. The few who did not, failed to show the desired results, or showed them in so lopsided and partial a manner that it was necessary to destroy them. All of this, of course had been mere preparation and experimentation with a view to later developments in human subjects. What SK540's gods had not anticipated was that they would produce a creature mentally the superior, not only of his fellow-rats, but also, in some respects, of themselves. He was a super-rat: but he was still a rat. His world of dreams and aspirations was not human, but murine. What would you do if you were a brilliant, moody young super-rat, caged in a laboratory? SK540 did it. What human beings desired was health, freedom, wealth, love, and power. So did SK540. But to him health was taken for granted; freedom was freedom from cages, traps, cats, and dogs; wealth meant shelter from cold and rain and plenty to eat; love meant a constant supply of available females. But power! It was in his longing for power that he most revealingly displayed his status as super-rat. Therefore, once he had learned how to open his cage, he was carefully selective of the companions--actually, the followers--whom he would release to join his midnight hegira from the laboratory. Only the meekest and most subservient of the males--intelligent but not too intelligent--and the most desirable and amiable of the females were invited. Once free of the cages, SK540 had no difficulty in leading his troop out of the building. The door of the laboratory was locked, but a window was slightly open from the top. Rats can climb up or down. Like a silver ribbon they flowed along the dark street, SK540, looking exactly like all the rest, at their head. Only one person in the deserted streets seems to have noticed them, and he did not understand the nature of the phenomenon. * * * * * Young Mr. and Mrs. Philip Vinson started housekeeping in what had once been a mansion. It was now a rundown eyesore. It had belonged to Norah Vinson's great-aunt Martha, who had left it to her in her will. The estate was in litigation, but the executor had permitted the Vinsons to settle down in the house, though they weren't allowed yet to sell it. It had no modern conveniences, and was full of rooms they couldn't use and heavy old-fashioned furniture; but it was solidly built and near the laboratory where he worked as a technician, and they could live rent-free until they could sell the house and use the money to buy a real home. "Something funny happened in the lab last night," Philip reported, watching Norah struggle with dinner on the massive coal-stove. "Somebody broke in and stole about half our experimental animals. And they got our pride and joy." "The famous SK540?" Norah asked. "The same. Actually, it wasn't a break-in. It must have been an inside job. The cages were open but there were no signs of breaking and entering. We're all under suspicion till they find out who-dunit." Norah looked alarmed. "You too? What on earth would anybody want with a lot of laboratory rats? They aren't worth anything, are they--financially, I mean?" "Not a cent. That's why I'm sure one of the clean-up kids must have done it. Probably wanted them for pets. They're all tame, of course, not like wild rats--though they can bite like wild rats if they want to. Some of the ones missing are treated, and some are controls. It would just be a nuisance if they hadn't taken SK540. Now they've got to find him, or do about five years' work over again, without any assurance of as great a success. To say nothing of letting our super-rat loose on the world." "What on earth could even a super-rat do that would matter--to human beings, I mean?" "Nobody knows. Maybe that's what we're going to find out." * * * * * That night Norah woke suddenly with a loud scream. Philip got the gas lighted--there was no electricity in the old house--and held her shaking body in his arms. She found her breath at last long enough to sob: "It was a rat! A rat ran right over my face!" "You're dreaming, darling. It's because I told you about the theft at the lab. There couldn't be rats in this place. It's too solidly built, from the basement up." He finally got her to sleep again, but he lay awake for a long time, listening. Nothing happened. Rats can't talk, but they can communicate. About the time Norah Vinson dropped off after her frightened wakening, SK540 was confronting a culprit. The culprit was one of the liberated males. His beady eyes tried to gaze into the implacable ones of SK540, but his tail twitched nervously and if he bared his teeth it was more in terror than in fight. They all knew that strict orders had been given not to disturb the humans in the house until SK540 had all his preparations made. A little more of that silent communication, and the rat who had run over Norah's face knew he had only two choices--have his throat slit or get out. He got. "What do you know?" Philip said that evening. "One of our rats came back." "By itself?" "Yeah. I never heard of such a thing. It was one of the experimental ones, so it was smarter than most, though not such an awful lot. I never heard of a rat with homing instinct before. But when we opened up this morning, there he was, sitting in his cage, ready for breakfast." "Speaking of breakfast, I thought I asked you to buy a big box of oatmeal on your way home yesterday. It's about the only thing in the way of cereal I can manage on that old stove." "I did buy it. Don't you remember? I left it in the kitchen." "Well, it wasn't there this morning. All I know is that you're going to have nothing but toast and coffee tomorrow. We seem to be out of eggs, too. And bacon. And I thought we had half a pound left of that cheese, but that's gone too." "Good Lord, Norah, if you've got that much marketing to do, can't you do it yourself?" "Sure, if you leave the car. I'm not going to walk all that way and back." So of course Philip did do the shopping the next day. Besides, Norah had just remembered she had a date at the hairdresser's. * * * * * When he got home her hair was still uncurled and she was in hysterics. One of the many amenities great-aunt Martha's house lacked was a telephone; anyway, Norah couldn't have been coherent over one. She cast herself, shuddering and crying, into Philip's arms, and it was a long time before he got her soothed enough for her to gasp: "Philip! They wouldn't let me out!" "They? Who? What do you mean?" "The--the rats! The white rats. They made a ring around me at the front door so I couldn't open it. I ran to the back and they beat me there and did the same thing. I even tried the windows but it was no use. And their teeth--they all--I guess I went to pieces. I started throwing things at them and they just dodged. I yelled for help but there's nobody near enough to hear. Then I gave up and ran in our bedroom and slammed the door on them, but they left guards outside. I heard them squeaking till you drove up, then I heard them run away." Philip stared at her, scared to death. His wife had lost her mind. "Now, now, sweetheart," he said soothingly, "let's get this straight. They fired a lab boy today. They found four of our rats in his home. He told some idiotic story of having 'found' them, with the others missing, running loose on the street that night, but of course he stole them. He must have sold the rest of them to other kids; they're working on that now." Norah blew her nose and wiped her eyes. She had regained her usual calm. "Philip Vinson," she said coldly, "are you accusing me of lying, or just of being crazy? I'm neither. I saw and heard those rats. They're here _now_. What's more, I guess I know where that oatmeal went, and the eggs and bacon too, and the cheese. I'm--I'm a hostage! "I don't suppose," she added sarcastically, "that your SK540 was one of the ones they found in the boy's home?" "No, it wasn't," he acknowledged uneasily. A nasty little icy trickle stole down his spine. "All right, Norah, I give in. You take the poker and I'll take the hammer, and we'll search this house from cellar to attic." "You won't find them," said Norah bitterly. "SK540's too smart. They'll stay inside the walls and keep quiet." "Then we'll find the holes they went through and rout them out." They didn't, of course. There wasn't a sign of a rathole, or of a rat. They got through dinner and the evening somehow. Norah put all the food not in cans inside the old-fashioned icebox which took the place of a refrigerator. Philip thought he was too disturbed to be able to sleep, but he did, and Norah, exhausted, was asleep as soon as her head touched the pillow. His last doubt of his wife's sanity vanished when, the next morning, they found the icebox door open and half the food gone. * * * * * "That settles it!" Philip announced. "Come on, Norah, put your coat on. You're coming with me to the lab and we'll report what's happened. They'll find those creatures if they have to tear the house apart to do it. That boy must have been telling the truth." "You couldn't keep me away," Norah responded. "I'll never spend another minute alone in this house while those dreadful things are in it." But of course when they got to the front door, there they were, circling them, their teeth bared. The same with the back door and all the first floor windows. "That's SK540 all right, leading them," Philip whispered through clenched jaws. He could smash them all, he supposed, in time, with what weapons he had. But he worked in the laboratory. He knew their value to science, especially SK540's. Rats couldn't talk, he knew, and they couldn't understand human speech. Nevertheless, some kind of communication might establish itself. SK540's eyes were too intelligent not to believe that he was getting the gist of talk directed to him. "This is utterly ridiculous," Philip grated. "If you won't let us out, how can we keep bringing food into the house for you? We'll all starve, you and we together." He could have sworn SK540 was considering. But he guessed the implicit answer. Let either one of them out, now they knew the rats were there, and men from the laboratory would come quickly and overwhelm and carry off the besiegers. It was a true impasse. "Philip," Norah reminded him, "if you don't go to work, they know we haven't a phone, and somebody will be here pretty soon to find out if anything's wrong." But that wouldn't help, Philip reflected gloomily; they'd let anyone in, and keep him there. And he thought to himself, and was careful not to say it aloud: rats are rats. Even if they are 25th generation laboratory-born. When the other food was gone there would be human meat. He did not want to look at them any more. He took Norah's arm and turned away into their bedroom. They stayed there all day, too upset to think of eating, talking and talking to no conclusion. As dusk came on they did not light the gas. Exhausted, they lay down on the bed without undressing. After a while there was a quiet scratching at the door. "Don't let them in!" Norah whispered. Her teeth were chattering. "I must, dear," he whispered back. "It isn't 'them,' I'm sure of it--it's just SK540 himself. I've been expecting him. We've got to reach some kind of understanding." "With a rat?" "With a super-rat. We have no choice." Philip was right. SK540 alone stood there and sidled in as the door closed solidly again behind him. How could one communicate with a rat? Philip could think of no way except to pick him up, place him where they were face to face, and talk. "Are your--followers outside?" he asked. A rodent's face can have no expression, but Philip caught a glance of contempt in the beady eyes. The slaves were doubtless bedded down in their hideaway, with strict orders to stay there and keep quiet. "You know," Philip Vinson went on, "I could kill you, very easily." The words would mean nothing to SK540; the tone might. He watched the beady eyes; there was nothing in them but intelligent attention, no flicker of fear. "Or I could tie you up and take you to the laboratory and let them decide whether to keep you or kill you. We are all much bigger and stronger than you. Without your army you can't intimidate us." There was, of course, no answer. But SK540 did a startling and touching thing. He reached out one front paw, as if in appeal. Norah caught her breath in astonishment. * * * * * "He--he just wants to be free," she said in a choked whisper. "You mean you're not afraid of him any more?" "You said yourself he couldn't intimidate us without his army." Philip thought a minute. Then he said slowly: "I wonder if we had the right to do this to him in the first place. He would have been an ordinary laboratory rat, mindless and contented; we've made him into a neurotic alien in his world." "You're not responsible, darling; you're a technician, not a biochemist." "I share the responsibility. We all do." "So what? The fact remains that it was done, and here he is--and here we are." The doorbell rang. Philip and Norah exchanged glances. SK540 watched them. "It's probably Kelly, from the lab," Philip said, "trying to find out why I wasn't there today. It's just about quitting time, and he lives nearest us." Norah astonished him. She picked up SK540 from the bed-side table where Philip had placed him, and hid him under her pillow. "Get rid of whoever it is," she said defensively. Philip stared for an instant, then walked briskly downstairs. He was back in a few minutes. "It was Kelly, all right," he told her. "I said you were sick and I couldn't leave you to phone. I said I'd be there tomorrow. Now what?" SK540's white whiskers emerged from under the pillow, and he jumped over to the table again. Norah's cheeks were pink. "When it came to the point, I just couldn't," she explained shamefacedly. "I suddenly realized that he's a _person_. I couldn't let him be taken back to prison." "Aren't you frightened any more?" "Not of him." She faced the super-rat squarely. "Look," she said, "if we take care of you, will you get rid of that gang of yours, so we can be free too?" "That's nonsense, Norah," Philip objected. "He can't possibly understand you." "Dogs and cats learn to understand enough, and he's smarter than any dog or cat that ever lived." "But--" The words froze on his lips. SK540 had jumped to the floor and run to the door. There he stood and looked back at them, his tail twitching. "He wants us to follow him," Norah murmured. There was no sign of a hole in the back wall of the disused pantry. But behind it they could hear squeaks and rustlings. SK540 scratched delicately at almost invisible cracks. A section of the wall, two by four inches, fell out on the floor. "So that's where some of the oatmeal went," Norah commented. "Made into paste." "Sh!" SK540 vanished through the hole. They waited, listening to incomprehensible sounds. Outside it had grown dark. * * * * * Then the leader emerged and stood to one side of the long line that pattered through the hole. The two humans stared, fascinated, as the line made straight for the back door and under it. SK540 stayed where he was. "Will they go back to the lab?" Norah asked. Philip shrugged. "It doesn't matter. Some of them may ... I feel like a traitor." "I don't. I feel like one of those people who hid escaped war prisoners in Europe." When the rats were all gone, they turned to SK540. But without a glance at them he re-entered the hiding-place. In a minute he returned, herding two white rats before him. He stood still, obviously expectant. Philip squatted on his heels. He picked up the two refugees and looked them over. "Both females," he announced briefly. "And both pregnant." "Is he the father?" "Who else? He'd see to that." "And will they inherit his--his--" "His 'super-ratism'? That's the whole point. That's the object of the entire experiment. They were going to try it soon." The three white rats had scarcely moved. The two mothers-to-be had apparently fallen asleep. Only SK540 stood quietly eying the humans. When they left him to find a place where they could talk in private he did not follow them. "It comes down to this," Philip said at the end of half an hour's fruitless discussion. "We promised him, or as good as. He believed us and trusted us. "But if we keep to our promise we're _really_ traitors--to the human race." "You mean, if the offspring should inherit his brain-power, they might overrun us all?" "Not might. Would." "So--" "So it's an insoluble problem, on our terms. We have to think of this as a war, and of them as our enemies. What is our word of honor to a rat?" "But to a super-rat--to SK540--" As if called, SK540 appeared. Had he been listening? Had he understood? Neither of them dared to voice the question aloud in his presence. "Later," Philip murmured. "We must eat," said Norah. "Let's see what's left in the way of food." * * * * * Everything tasted flat; they weren't very hungry after all. There was enough left over to feed the three rats. But they had evidently helped themselves earlier; they left the scraps untasted. Neither of the humans guessed what else had vanished from the pantry shelves--what, when he had heard enough, SK540 had slipped away and sprinkled on the remaining contents of the icebox, wherever the white powder would not show. They did not know until it was too late--until both of them lay writhing in their last spasms on their bedroom floor. By the time the house was broken into and their bodies found, SK540 and his two wives were far away, and safe.... And this, children, is the true account, handed down by tradition from the days of our great Founder, of how the human race ceased to exist and we took over the world. 
51824	----	Star-crossed? Worse than that! Even Earth itself was hopelessly out of reach for these landlocked space-travelers who lived in a-- World in a Bottle By ALLEN KIM LANG Illustrated by DICK FRANCIS [Transcriber's Note: This etext was produced from Galaxy Magazine October 1960. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] Pouring sweat and breathing shallow, I burned east on U.S. Twenty at ninety miles an hour, wishing I could suck into my lungs some of the wind that howled across the windshield. I heard the siren in my phones. I glanced out the left side of my helmet to find a blue-clad figure on a motorcycle looming up beside me, waving me toward the shoulder. A law-abider to the last gasp of asphyxia, I braked my little green beast over to the berm. The state cop angled his bike across my left headlamp and stalked back to where I sat, tugging a fat book of traffic-tickets out of his hip pocket. "Unscrew that space-helmet, Sonny," he said. "You've just been grounded." "Grounded, I'll grant," I said, my voice wheezing from the speaker on the chest of my suit; "but I can't take off the fishbowl, officer." "Then maybe you'd better climb out of your flying saucer," the policeman suggested. "And if you're toting pearl-handled ray-guns, just leave 'em hang." I got out of the car, keeping my hands in view, feeling like the fugitive from a space-opera this cop evidently took me for. He examined me the way a zoologist might examine the first live specimen of a new species of carnivore; very interested, very cautious. After observing the cut of my wash-and-wear plastic sterility-suit--known to us who wear them as a chastity-suit--the policeman walked around me to examine my reserve-air tank, which is cunningly curved and cushioned against my spine so that I can lean back without courting lordosis. He inspected the bubble of plastic that fit over my head like the belljar over a museum specimen, and stared at the little valve on the left shoulder of my suit, where used air was wheezing out asthmatically. "I guess fallout has got you bugged," he said. "Not fallout, bacteria," I explained. "I'm one of the Lapins from Central University." "That's nice," the policeman said. "And I'm one of the Bjornsons, from Indiana State Police Post 1-A. What were you trying to do just now, break Mach One on wheels? Or do you maybe come from one of these foreign planets that don't know the American rules of the road?" I breathed deep, trying to find myself some oxygen. "I was born right here in Indiana," I said. "The reason I'm wearing this suit and helmet is that I'm bacteriologically sterile." "So maybe you could adopt a kid," Officer Bjornson suggested. "Sterile like germ-free," I said. "Gnotobiotic. I grew up in the Big Tank at Central University." * * * * * "You'll spend the night in the big tank at South Bend if you're snowing me, Sonny," he said. "Let's see your driver's license." I got my billfold out of the glove-compartment--a chastity-suit doesn't have any pockets--and handed my license to Bjornson. "John Bogardus, M.D.," he read. "You're a doctor, eh? This says you live at BICUSPID, Central University, South Bend. What's that BICUSPID, Doc? Means your practice is limited to certain teeth?" "I'm a resident in pathology, and I'm damned near out of air," I said, annoyed at the prospect of suffocating while acting straight-man to a state cop. "BICUSPID is the acronym for Bacteriological Institute, Central University Special Projects in Infectious Disease. I'm a Lapin, which is a human guinea-pig. I'm sorry, officer, that I broke the Indiana speed-limit but my air-filter is clogged with condensation. If I don't get back to the Big Tank at the University within the next few minutes, I'll run out of air. And you'll have to spend the rest of the evening testifying before St. Joseph's County Coroner." "So what happens if you crack open your space-helmet and breathe the air us peons use?" he asked. "Pretty quick, I'd die," I said. "I've got no antibodies, no physiological mechanism to combat inspired or ingested bacteria." "That's the sort of answer that makes my job the joy it is," Bjornson said. "Next thing you know, I'll be chasing drunken drivers from Mars." "There's no intelligent native life on Mars," I said. "You think maybe there are intelligent natives on U.S. Twenty?" he asked, returning my license. "Okay, Doctor Bogardus, I've bought your story. You leadfoot your bomb along after me, and we'll hit the Central campus like we're crossing the payoff line at the Mille Miglia." Bjornson cowboyed into the saddle of his bike, spurred it off and cut siren-screaming down the concrete toward South Bend and Central U. I jumped back into my sports-car and tailed him, the wind soaring past my 'phones like rocket exhaust. We cut through the field of Sunday drivers in a horizontal power-dive. I was half-blinded by the sweat condensed on my air-cooled face-plate. Formaldehyde bath or no, I'd have to cut in my reserve-air pretty soon. * * * * * We made it while I was still breathing. I braked in front of the BICUSPID entrance and walked as fast as I dared, dizzy and panting with the concentration of CO_{2} bottled up with me in my chastity-suit. Outside the door to the contaminated labs, I shook Bjornson's hand and told him that I considered the expense of my Gross Income Tax justified by his employment. I went inside then, climbed the steel steps to the glass-walled shower. I cut in my suit-radio and announced my arrival. "Bogardus here. I'm nearly out of wind; my filter's soaked. I'm cutting in reserve-air. Anybody around to see that I scrub behind my ears?" Dr. Roy McQueen, Director of BICUSPID, came out of his office, where he'd monitored my announcement from the loudspeaker set above his desk, and faced the glass door of the shower room. He waved to me and cut on his microphone. "Okay, Johnny," he said. I sealed off my air-filter and cut in the reserve-air. That canned wind felt to my lungs like cold beer to the throat on a July day. I felt the oxygen percolating through me to my toes and finger-tips, tingling them back to life. Turning on the detergent shower, I sloshed around beneath it, washing the outside dust off my chastity-suit. "You're dry by the tank," Dr. McQueen said into his hand microphone. I picked up the long-handled shower brush and scrubbed back there. I showered the suit's armpits, the folds behind the knees, the soles of the suit's boots, scrubbing hard with the brush. "You're all wet, Johnny," the Chief said. "Got enough air for half an hour in the bathtub?" "Yes, sir," I said, checking the gage of my reserve-air tank. Having scrubbed off most of the flora I'd picked up in the great wild world of Indiana, I climbed down through the manhole into the bathtub, a sump of formaldehyde solution eight feet deep. I sat on the iron bench at the bottom to soak. "How about switching on some music, Chief? I didn't think to bring anything waterproof to read." "You'll hear music from me," Dr. McQueen said. "This is a big day for BICUSPID, Johnny. It's the first time one of you kids ever came home from a date with a police escort. What happened? Anne's old man decide he didn't want a plastic-wrapped son-in-law? He call the law to throw you off his front porch?" "My air-filter got bolixed," I explained into the microphone, "so I leaned on the gas pedal pretty heavy on the way home. A friendly gendarme named Bjornson turned up." "You should be more careful, Johnny. I'd hate to have to post you." Like the rest of us, Dr. McQueen did post-mortems on the germ-free animals who died of old age or stir-fever in the Big Tank, or had to be sacrificed as routine sterility controls. Last winter, for the first time, the Chief had had to autopsy one of us Lapins. Poor Mike Bohrman had gone off his rocker and stripped off his sterility-suit in the snow. All we wear underneath is a pair of shorts. That's the way Mike had run around, almost naked in a northern Indiana February. It was hours before he'd been missed. He went to the hospital with severe frostbite, but he died two days later of pneumonia complicated by streptococcal septicemia. "Stick around down there, Johnny," the Chief said. "I'm coming down to join you." * * * * * I heard him turning the monitor microphone over to one of the technicians out in the contaminated labs. Oh hell, I thought. Here comes a chewing-out that would leave me raw up to the duodenum. The worst thing about being told off when you've done something dumb is the futility of being told about it. Nobody knew better than I that it was stupid to stay outside the Big Tank for eight solid hours. Hydraulic pressure aside, a chastity-suit isn't designed to hold a man more than about four. It took Dr. McQueen a quarter hour to get suited up and scrubbed. Then he came down the ladder to join me in the pale green soup, his air-hose snaking along behind him like strayed umbilical cord. He sat on the bench beside me. Before he cut in his suit radio, he leaned close and touched his helmet to mine. "Damn it, Johnny! If you don't stop chasing after that dame in Valpo, I'll toss mothballs in the gas-tank of your silly little car." Then he toggled his radio. "Testing," he said, for the benefit of the monitoring technician listening out in the contaminated labs. "This is McQueen. Someone suited up?" "Safety man is suited and scrubbing, Chief," the monitor said. "I read you loud and clear. Now, let's hear from you, Brother Bogardus." "This is John Bogardus, the Voice of Purity," I said, "broadcasting from the bottom of Central University's lovely BICUSPID pool. You want I should dedicate my next record to the gang at the brewery?" "Happy to hear you testify, canned-goods," the technician said. "The I.U. game is on the radio now. You want me to pipe it to the phones so you can hear our team smear 'em?" "I'll take your word for it that they'll do that," I said. "My sport is balk-line billiards." Eighty years ago, Central University's gate receipts from football had made possible the first BICUSPID program in gnotobiotics, using mice and roaches and hamsters. Despite this historical tie between me and football, I felt no special affinity for the game. "Trouble with you, canned-goods, is you've got no school spirit," the monitor complained. "If you or the Chief feel your feet getting wet, just whistle. I'll be here." "Will do." For all the thousands of times I'd been through this antiseptic drill, I was happy to know that a lifeguard was suited up above our poisonous bathtub, ready to fish either of us out should our suits spring a leak. If formaldehyde-methanol started seeping into my chastity-suit, I knew I'd have an overwhelming desire to undress. Dr. McQueen cleared his throat, a sound which broadcast very like a growl. "Okay, Johnny. Let's have a synopsis of your Sunday outing." * * * * * "It's springtime, Chief," I said. "You know what the month of May does to a young man's fancy, and reticuloendothelial system, and all." "I wish you'd stop seeing her," the Chief said. "You've got fifteen of the most nubile girls in the Midwest living in the Big Tank with you. Sweet, intelligent--available. So why did you have to get the hots for an outsider?" "It's that ol' debbil incest-taboo, Chief," I said. "I've slept amongst those fifteen canned peaches for the last twenty-three years. The result is that my warmest feeling toward any of them is brotherly love. Who itches to shack with a sibling?" "Your only alternative seems to be a lifetime of cold showers," McQueen said. "Speaking of canned peaches, have you seen Mary deWitte today?" "No." "Mary has extramural interests, too," he said. "Her intended is a basketball player in pre-Law. A fellow roughly fifteen feet tall. Mary has been gone all day. I presume that she's been visiting this legal obelisk; and I'm beginning to feel the twinges of fatherly anxiety. But tell me about Anne, Johnny." "I met her at a concert last fall," I said, not giving a damn about the safety man and the monitor kibitzing. "Anne didn't bug at my chastity-suit the way most of the hens on campus do. This impressed me. She liked the way I talked, even though she could hear my voice only from the speaker on the chest of my suit. I liked fine the way she listened. So we had a date. Lots of dates. Said goodnight by shaking hands--Please Excuse My Glove. "One evening we drove down to the beach at Hudson Lake. As we lay there on the sand, I pointed out for Anne the red disk of Mars. I told her about the men up there, at New Caanan and Bing City and Bitterwater, working to uncover one world while they built a new one. I told her about the mystery of the Immermann skull, and what it might mean. I pointed to the stars and named them for her. All the time, Chief, I knew that I could touch Betelgeuse or Phobos as easily as I could touch Anne. "Anyway, we went swimming together, just like we were in Technicolor and Vista Vision. I screwed the cap on my air-filter and breathed from the reserve tank. Anne wore a bikini. I might as well have been aboard a midget submarine. After that evening, we decided not to go swimming any more; and Anne started wearing strict and conservative clothes." "What happened today, Johnny?" McQueen asked me. "What could happen?" I demanded. "We broke up. She's contaminated, poor girl. She's been aswarm with bacteria and yeasts and molds and miscellaneous protista ever since the obstetrician slapped her on the rump, while I'm Boy Galahad, fifty-six one-hundredths percent purer than Ivory Soap. My strength is as the strength of ten, so I told Anne at noon today that she'll have to find herself a new boy friend. She needs a guy who can eat the other half of the pizza with her, someone who can lend her his comb and breathe the air she breathes. It took me weeks to steel my soul to the prospect of kissing Anne off--there's an ironic metaphor for you, Chief--but I did it." "I'm sorry, Johnny," McQueen said. "I'm afraid I've diluted the antiseptic with my tears," I said. "Just singing those old formaldehyde blues." I'd soaked for the regulation half-hour now, and the gage of my reserve tank was on red, so I got up to go. "I can see myself at ninety-five," I said. "I'll be patriarch of the Big Tank. The oldest male virgin on campus. See you inside, Chief." I climbed up the ladder through the second manhole over the formaldehyde sump and stepped out into the sterile precincts of the Big Tank. Home. * * * * * I stepped into a shower-booth, let the water blast the formaldehyde off my chastity-suit, popped off my helmet and stripped. Air against sweat-steamed skin felt good. I showered again, naked. I blotted myself dry and dressed in fresh shorts, all the clothing a man needed in the air-conditioned Elysium of the Big Tank. I carried my suit into the locker room to refit it for my next trip outside. Snapping its collar to the bushing of the compressed-air supply and turning on the pressure, I inflated my suit so that it stood on its headless shoulders, ready for inspection. The wet air-filter that had almost asphyxiated me had been caused, I discovered, by a break in the moisture-trap of the unit. Careful checking assured me that the filter had failed-safe bacteriologically. No outside bugs were in my suit. I might have suffocated, but my corpse would have remained uncorrupted. Such a comfort. I replaced the trap and filter with a fresh unit and fit a charged bottle of air onto the back of the suit. Then I gave every inch of my chastity-suit an inspection for worn spots, for bubbles forming on its moist surface--an inspection as painstaking and as sure as a window washer's check of his working harness, or an exhibition jumper's folding of his parachute. Satisfied that the suit was all set for my next adventure into the world of normal, septic human beings, I racked it and the helmet in my locker and walked out into the garden. There I stretched out on the grass under the ultra-violets, refreshing my tan while I waited for Dr. McQueen to come up from the sump. The garden was my favorite room in the Big Tank. It was in establishing the garden that I'd discovered that my Machiavellian mind is articulated to a pair of green thumbs. The crafty bit came over coffee in the cafeteria. I, of course, just sat there to listen and talk; not even C.U. Cafeteria coffee is aseptic enough for a Lapin to drink, even if there were some way to get a cup of the stuff inside the helmet of a sterility-suit. Anyway, I chided these two graduate students from the botany department about the research possibilities they were missing by not growing any gnotobiotic green stuff. I gave them the Boom-Food pitch. Would cabbages, grown in an environment free of bacteria, grow large as king farouks? I hit them with the Advance the Frontiers of the Biological Science line: could soil-nitrates be utilized by legumes in the absolute absence of _Nitrobacteriaceae_? * * * * * The two botanists leaped to my vegetable bait like a brace of starving aphids. A couple days after I'd commenced my con, three tons of quartz sand were shipped through the Big Tank's main autoclave. The lifeless stuff was poured over a grill of perforated pipes. The pipes were connected to a brew-tank of hydroponic juices, and the wet sand was planted with germ-free seeds of grass, tomatoes, carrots, and other useful herbs. We Lapins had a ball, planting the aseptic seeds in the dirtless dirt eagerly as a band of ribbon-hungry 4-H'ers. What had been our sun-room blossomed, after a decent period of germination, into our lawn and garden. For some reason, the garden of our Eden never got an apple-tree. But we did have lettuce on our sterile sandwiches now, and fresh tomatoes, infinitely superior in texture and taste to the "radared" fruit--almost pureed by the high-energy beams that made it germ-free--that we'd grown up on. The lesser mammals with whom we twenty-nine Lapins shared the Big Tank, the rabbits and guinea-pigs and hamsters and like small fowl, didn't go much for fresh vegetables, having developed a palate for an autoclaved diet. The monkeys, though, proved to be real competitors for carrots and raw sweet corn. They had to be locked out of the garden, rather as certain of their disobedient relatives had been. I reached out from my supine, sun-drenched position to pull a turnip. I shook off the moist sand and wiped the hydroponic wetness off my shorts, to munch grittily while I waited for the Chief to join me. As soon as he'd soaked in the formaldehyde mixture for half an hour, Dr. McQueen came up through the manhole. Under the shower he squirted the chemical B.O. off his modified sterility-unit, then came out into the garden to join me, dragging his air-hose. We sat side by side on the park bench I'd built beside the onion-patch. (I was fond of my onions. They were the only living things in the Big Tank with the honest stink of life to them). "Where did you plant the marijuana, Johnny?" the Chief asked me. His voice was muffled by the wetness of his suit-speaker. "Now, there's a pregnant idea," I said. "We won't plant muggles, Chief. We'll plant tobacco. All we Lapins need to keep us happy is a good solid vice like smoking." I looked at the Chief. "Why'd you follow me here, Dr. McQueen? I know I've been naughty." "Self-pity doesn't become a man, Johnny," he said. "And why the hell not?" I demanded, my blood-pressure ready to challenge any manometer in sight. "If I can feel compassion for some poor joker on TV, why can't I hurt a little for myself--for John Bogardus, swaddled from his darling by a damned plastic diving-suit? I was--I am--in love with Anne, Doctor." "Your marriage-night would kill you, John," he said. * * * * * I jumped up with ready-made fists, then flopped down onto the grass, laughing at the picture I saw. Battle of the Century. In this corner, wearing helmet, chastity-suit, and thirty-five feet of air-hose Roy McQueen, Ph. D. In the far corner, clad only in brown trunks (grass-stained on the seat, folks), John Bogardus, M.D. "It makes a grand old dirty joke, doesn't it?" "It makes a painful reality," Dr. McQueen said. "I know how you must lie awake nights, thinking about gradually acclimatizing yourself to the contaminated world in which Anne lives. You know, though, that the death-rate with the lower animals who've tried this acclimatization is steep. Even the survivors don't survive very long, because of their low gut-tone and their tardy antibody response. I suppose, though, that the imminence of death is as helpless before love as the locksmith." Dr. McQueen sighed. "If it's what you want, Johnny, I'll ignore everything we both know about the probable consequences and help you break out of here.... Think how embarrassed you'd feel, though, if you died of a _B. subtilis_ septicemia or a fulminant chicken-pox the day before the wedding." "I could have married Anne, and made her either an unkissed bride or an early widow," I said. "Neither of these alternatives struck me as an attractive career for the woman I love, so I left her. It's so logical it's practically simple arithmetic. Anne put up a fight to keep me, Chief; it was most warming to my amour-propre. Women aren't logical like us men of science. What a stinking situation!" "It is," Dr. McQueen said. "But remember, John, lovers outside the Big Tank often get just as star-crossed as you and Anne." "And they have dental caries to contend with, which we don't," I said. "Somehow, Chief, we'll get this experiment into its second generation, past the miseries of the gnotobiotic first-born, we Adams and Eves who were delivered into purity by aseptic Caesarian section. Maybe we'll have to toss coins or draw cards to pair up for parent-hood. But any kids we raise will be spared that indignity. Know how I've got it figured, Chief? We've got to make provision for exogamous matings, right? Novelty, in other words, is essential to romance. Here's the way we'll work it. We'll set half the babies, boys and girls together, on one side of a wall, half on the other side. We'll have established two tribes of kids, each growing up in ignorance of the other; and we'll keep them strictly apart till they're in their middle teens. Then, maybe the night of the Junior Prom, we'll cut a door-way in that wall and introduce them to each other." * * * * * Dr. McQueen smiled. "That will be a splendid evening, John. And a situation to make an anthropologist's mouth water. You may have found the answer to one of your children's major problems. I only wish we had as simple a solution to the current troubles of John Bogardus." "Don't blame yourself for what's happened to me," I said. "I've carried on pretty bad today, but that doesn't mean that I or any of the other Lapins blame you for causing us to be birthed into the Big Tank. It had to be done. Once Dr. Reyniers had made gnotobiotics possible, a colony of germ-free humans became available. You did a good and honest job of bringing us colonists up, Chief. As good a job as anyone could do." "Thank you, John," he said. "I often wonder, though, whether the Nuremberg Principles really gave us the right to build and populate this germless microcosm. We told your mothers when they volunteered that the results of raising humans gnotobiotically would be important. They have indeed. Thousands of lives have been saved by what we've learned here. We saw to it, as we'd also promised your mothers, that your health hasn't suffered by reason of experiments, that you've been given the education you need to earn a good living, and especially that your dignity as human beings has always been respected. The core question is, did we have the right to involve fellow humans, not yet born, in a process the end of which we couldn't entirely predict? Enough of this, though. My conscience is my own problem. For your immediate relief I can offer only: keep busy." "Work is dandy, but liquor's quicker," I said. "A wound of the heart calls for a therapeutic drunk." "I'll honor your prescription, Doctor," the Chief said. "The moment I get outside, I'll Seitz you some of my own Scotch." He stood up and caught hold of his air-hose. "Forgive me for behaving so like Pollyanna, John," he said. "I wish I could offer you relief more potent than Scotch and sympathy." "Such spiritual Band-aids are all the help there is, Chief. Thank you for them." He slapped me on the shoulder with his gloved right hand, then walked through the shower-room, trailing his black air-hose, and dropped down the manhole into the formaldehyde sump on his way back out into the world. I sat on my bench in my artificial garden in the middle of the great steel womb I'd been delivered into, and I thought about my Anne. * * * * * "If I had a chisel and about four tons of Carrara marble," the girl standing behind me said, "I'd hack me out a statue on your model, and call it _The Thinker_." Dorothy--the Firebird--Damien plumped her little backside onto the bench beside me and scintillated eagerness to converse. I didn't want to talk to anyone at the moment, certainly not to the Firebird. To employ a metaphor from an appetite less exalted than love, seeing the Firebird after losing Anne was too much like being offered hamburger after having had a filet mignon snatched from under nose. Still, as my peripheral vision took in the Firebird's brilliantly distributed five-foot-three, I realized that my metaphor was false. That flame-colored hair and impish, freckled face; that halter taut as a double-barreled ballista cocked to fire twin rounds; I turned my attention to the girlscape beside me, quite innocent of covetousness, my interest purely aesthetic. No hamburger, this. Firebird Damien was filet mignon. But she wasn't Anne. Suddenly I was contrite toward my fellow captive. "You're looking splendid, Miss Damien," I said. "And you got a face peeled off the iodine bottle. Tell mamma where it hurts." "Don't delve, doll." "Woman-trouble?" she asked. "The term is tautological," I said. "_Woman_ and _trouble_ are synonyms. If the language had any logic the words would rhyme." The Firebird put a freckled arm across my shoulder and squeezed my deltoid with her resting hand. I shrugged. "Don't try to shake me loose, Johnny," she said. "I'm trying to find out what sort of people you are. Whether you're a Shrinker or a Flesh-Presser." "Obviously, you're of the Shrinker persuasion," I said. "Hoo-hah! Shrinkers are the other race from me," the Firebird said. "They're the people who quail at shaking hands, who never slap a back nor playfully pinch. They hate to be crowded, don't like to be touched. My sort of people, though, tend to cuddle like puppies, or like cattle in a thunderstorm; we take comfort in the closeness of other humans. We're not erotic about this, Johnny. Not necessarily erotic, I mean. We have our moments, too, or the Shrinkers would long since have taken over the world in spite of their dreadful handicap. We're the people who make brilliant barbers. The kind who say hello to you with a Roman handshake and a clasp on the shoulder. We're the doctors with the healing touch, the most tender nurses. We're the Flesh-Pressers." She gently squeezed my shoulder-muscle again to demonstrate. "Tell me what's the matter, Johnny. Maybe I can help." * * * * * "No magic touch will cure my trouble," I said. "Anne and I are through. It was hopeless. I was like the goldfish in love with the cat. So I called our romance to a halt today and drove home in my little green sports-car, feeling a little green and hardly sporty at all. Please don't mention this again, Firebird; not till I'm old and bald and my wound has healed to a thin white scar." "Can I say one thing?" "You will, so do." "I'm really sorry, Johnny." "Thank you, Firebird," I said. "The Chief promised to send some therapeutic juices through the Seitz filter. If you've a mind to sample a little sterile White Horse, perhaps tie one on with me this evening, you'd be most welcome." "I'll be proud and happy," the Firebird said. She scooted even closer. I found her propinquity not at all unpleasant. Was I perhaps of the Flesh-Presser clan myself? The girl smelled good, the faint wholesome feminine odor of my Lapin foster-sisters--a perfume an outside wench, host to a universe of bacteria, could approximate only with Pepsodent and the most meticulous attention to her underarms, I gather from TV. "How am I to entertain you, sir?" the Firebird asked me. "I have current gossip, vintage scandal, clever anecdotes lifted from the steaming pages of my autoclaved _Reader's Digest_, imitations of bird-songs--heavy on the mating-calls, these--and sheer adoration." She paused. "Scratch that last offering, Johnny," she said. "It's un-hygienic for a girl to wear her heart on her sleeve, even here." "I've lost touch with the Big Tank social whirl these last few weeks," I said. "I've been spending all my alive-time in the greater world of Valparaiso, Indiana. Bring me abreast of the local gossip, Firebird, if you please." "Gladly. First there's the case of Mary deWitte. She's still on the trail of her basketball star--a fellow named Lofting--confident that somehow they'll manage to compromise her hateful purity.... Maybe I shouldn't have mentioned Mary," she said, seeing that I was frowning. "I was just thinking," I said. "Miss deWitte and I might get together to establish an Amour Anonymous group in the Big Tank." "If you do, Johnny," the Firebird said softly, "write me up a card as a charter member." "The Chief was talking about Mary deWitte only a few minutes ago," I said. "Hasn't she accepted the fact that we Lapins can't hope to breed with those jungle weeds outdoors?" "Have you accepted that fact, Johnny?" the Firebird asked. "Apt question," I admitted. "Sure. I've decided that Anne is as unavailable to me as Mars is. I don't know which makes me more bitter, Firebird; losing Anne or being denied the chance at the stars. Now that the solar system is getting man's footprints all over it, now that the Orion ships are slamming out to Mars and back on a busline's schedule, and the biggest ship of all is being fitted for deep space at the back of the moon, the constellations don't seem much further off than Chicago. But not for me." "You think you're bitter, bud, you should hear me with my hair down," the Firebird said. "But we've had dirges enough for one evening. Your whiskey should be filtered through by now. Let's go wet our Scotch apéritif, and have dinner." "I'm not hungry," I said. "I just ate a turnip." "Will turnips make you big and strong? You need solider food, like Scotch. That's my professional opinion, Doctor." She got up and tugged at my hand. "Come on, Johnny. I'm not about to let you sit here all evening and brood." "Is this your prescription, sweet Firebird?" I asked. "That I'm to go back to the madding crowd, mingle with my twenty-eight fellows in aseptic togetherness? Well, you're probably right." I got up from my park-bench to walk with her, hand-in-hand, to the dining room, stopping en route at my room for a shirt. Dinner was a formal affair in the Big Tank, shirts for the gentlemen and shoes for all. * * * * * The other Lapins were already eating. They greeted me and especially the Firebird with jokes and fellowshippy sounds. I felt very much at home with them. There was Bud Dorsey, our weight-lifting astrophysicist, his magnificent u.v.-blackened body a study in the surface musculature of the human male. At his table was Karl Fyrmeister, who has a practically complete collection of the airmail stamps of the world to console him on long winter evenings. All the stamps are quite sterile. Karl was talking with Gloria Moss, whose academic specialty was group dynamics. She demonstrated muscular dynamics so attractively that when she walked about the campus in her chastity-suit she drew whistles, a truly remarkable accolade when you consider that the c-suit is somewhat less faithful to the wearer's form than a poncho. Keto Hannamuri sat the four-place table with Bud and Karl and Gloria. He was my fellow-medic among McQueen's Beasts, a pediatrician. Kids loved him. Wearing his sterility-suit as he made his Ped Ward rounds, that Oriental smile showing through the face-plate of his mask, Keto seemed to the television-nurtured youngsters the very model of the friendly extra-solar alien, complete with space-suit. Besides his flair for showmanship, Keto was a remarkably fine doctor. As we passed his table, he slapped the Firebird's short-shorted callipygia in a kin-ship-gesture of the Flesh-Presser clan. I felt a sudden overwhelming love for all these people, my brothers-and-sister-in-exile. I took my tray to sit down quick with the Firebird before my reserve, depleted by the emotional beating I'd taken at noon, gave way. The menu featured radared steak. The meat was germ-free and somewhat tenderized by the high-energy beams. (A purist in culinary proteins might go so far as to say denatured.) The nearest any Lapin came to ingesting a bacterium was here at the table, where we ate billions of bacterial corpses. The bugs achieved a post-mortem revenge by triggering the production of faint bacterial antibodies in our blood. Besides the steaks and the myriads of murdered microbes, we had an aseptic salad prepared from Tank-grown hydroponic vegetation, dressed with Roquefort, the cheese that vies with penicillin in my private hall of fame as the noblest product ever a mold gave man. The Scotch that Dr. McQueen had promised to send was on hand, Seitz-filtered into a sterile White Horse bottle. Not really caring to dilute my poignancies with alcohol, I passed the whiskey among the tables nearby. * * * * * The Firebird was managing to stay quite close to me, though technically remaining on her own side of the table, eating and talking and now and then flashing me such a glance of yearning that I was pierced by the sight of her and by a remembered line of e. e. cummings's: "... your slightest look easily will unclose me though I have closed myself as fingers...." Just as suddenly, I realized that mine was a highly pathological state of mind, the rinse-phase of the brain-wash. Autism can be produced as surely by loneliness or unrequitable love as by injections of LSD-25. So I turned my attention to my environment, consciously flexing my muscles of mental health. I answered the Firebird's sallies with automatic flippancy. I ate my steak, savoring its flavor. And I looked about the dining-room, examining it as though I'd never eaten there before. The Lapins' dining-room in the Big Tank is about the size of a railroad restaurant car. (Not that I've ever been aboard a train to make the comparison. The stringencies of the sterility-suit tie such of us to the Big Tank on a short leash: the most sanitary of outside washrooms would prove a pesthole to a Lapin.) The kitchen, which was under the supervision of the Firebird, our dietitian, could have been squeezed into a telephone booth. It served chiefly as receiving-station for the autoclave and the radar-room, through which all our food came. With its ten little four-place tables, each covered with a gypsy red-checkerboard cloth, set with a green glass vase of Tank-grown daisies, our dining-room was friendly enough. The Tank-ness of it, though, was emphasized by a mural along one wall, a fantasy of stars and men and microbes that half a dozen of us had planned and painted one week. Where the mural was now had once been a picture window, overlooking a green stretch of Central campus, a source of comfort to us all. An Air Force jet, though, pulling out of a dive invisibly above us, had sonic-boomed a crack in both panes of the double glass of the window, causing a general alert as we realized that some airborne _Proteus_ or fortunate _Staphylococcus_ or lonely _Aspergillis_ might have invaded our fortress through this almost microscopic breach in our walls. Careful decontamination had saved our sterility, but now the Big Tank had no window. "I was saying...." the Firebird said, in a firm voice. "Sorry, doll. You were saying?" "That Mary deWitte isn't here. Do you suppose she's still outside? She checked out her sterility-suit about the same time you did." "That's a good nine hours ago," I said, glancing at the clock set over Saturn on our mural. "Either Mary has been on a restricted-fluids diet, or True Love has made her careless of visceral discomfort." "Don't be coarse, Johnny." "The demands of the kidney are as exigent as those of the heart, Firebird," I said. "I think I'd better call Dr. McQueen." "You'll only cause trouble for her and Lofting," Firebird said. "I've decided that it's better to be lovesick than dead," I explained, getting up from the table. * * * * * I went to the phone in the corner of the dining-room and dialed Dr. McQueen's home. "Chief? John Bogardus. Mary deWitte still hasn't come home to roost. I think we'd better find her before she does something splendid and foolish." "Like perhaps marrying her contaminated basketball-player and setting out on a suicidal honeymoon?" Dr. McQueen suggested. "You're right, John; we should prevent that sort of thing. The rub is, we're too late. I got a phone-call from Mary a few minutes after I got home this evening. She abandoned her sterility-suit in a downtown Chicago hotel room at noon today, and married her fledgling lawyer in a civil ceremony at one o'clock. I tried to find out from her where she was, but she just said she was very happy and hung up." "Hell! What are we going to do?" "I'm flying to Chicago, where I'll ask the help of the police in finding Mary," the Chief said. "Once I've run down the happy couple, though, damned if I know what I'll do next. Shall I stand outside the bridal chamber with a syringeful of broad-spectrum antibiotics, waiting for Mary to sneeze?" "They'll have a short marriage," I said. "Mary knows how likely it is that she'll never grow old," Dr. McQueen said. "But I suspect that she hasn't said a word to her husband. I'd better go now, John. My plane leaves in twenty minutes." "Don't let this prey on you too much, Chief," I said. "We Lapins have free will, too. We're old enough to bear the responsibilities for our own actions." "Thank you, Johnny." Dr. McQueen hung up. I returned to the table with no enthusiasm for the remaining half of my steak. "What's up, Johnny?" the Firebird asked me. "Now we are twenty-eight," I said. "They were married in Chicago at one o'clock." "How wonderful!" the Firebird exulted. She stood and pounded our table-top with the vase, scattering damp daisies on the cloth. "Quiet, everybody! I've got an announcement." The chatter over dessert simmered down. "Mary deWitte got married today--here's to the bride!" Firebird slopped two ounces of White Horse into her glass and downed them at a heroic gulp. She sat, sputtering. The chatter at the other tables crescendoed as our colleagues reminded one another of the significance of the Firebird's news. "Will you also propose the toast at Mary's wake?" I asked. * * * * * "What a hideous thing to say!" "It was, Firebird," I said. "Forgive me, please. This thing has left me in a wounding mood." "Is Mary really in such danger?" Firebird asked. "She may last a week, not much more. Today she'll meet _Klebsiella_, probably; perhaps _E. coli_ and _Shigella_. Pretty soon she'll start to sniffle with the first common cold she's ever experienced. Polio virus and the ECHO group may get to her first, and establish themselves before there is sufficient growth of bacterial flora to give them competition. Her intestinal walls are thin and weak, so she may suffer megacolon as a result of gas-producing fermentation. From a pathologist's point of view, I'll find it most instructive to learn the manner of Mary Lofting's death. From the standpoint of a friend and fellow Lapin, though, I'll think her death a damned shame." "I'm getting a little drunk, Johnny," the Firebird said, "and a little maudlin. So, say you're right. After all, you're the doctor and I'm just a dumb dietitian. But don't you think maybe it's worth while, what Mary's done? Condemning herself to die, I mean, because she's really in love, and death is what she's got to pay for a few days' happiness. Don't you think the price is fair, Johnny?" "If I did, I'd be paying it," I said.... "No, Firebird. Seizing a little love and poetry before the sacrifice is great stuff for epics, but it doesn't make much sense to me. When I'm married I'll want to see my children all the way through Spock and Gesell. I'll want to grow old with my wife, if you'll excuse the corn." "We Flesh-Pressers have a natural reverence for corn," the Firebird said. "It's part of the syndrome. Johnny, if you really want what you just said, want those things badly enough to set up a marriage on half a love, give me a call. Anytime. Even though I don't set your blood aflame." She stood up, a little unsteady, and rubbed her hand across her eyes in a tardy effort to hide tears. "Save the brushoff till tomorrow, Johnny," she said. "Goodnight." "Goodnight, sweet Firebird," I said. She turned and walked quickly from the dining-room. Bud Dorsey, our weight-lifting astronomer, left his three companions to bring his coffee over and sit with me. Bud was the Lapin who'd have been a Central U. fullback as an undergraduate, if only Dr. McQueen had let him play the game in a chastity-suit. "What will happen to Mary deWitte, John?" he asked. "She'll die," I said. "One flight in the sunlight, then her wings fall off. We Lapins are a fragile race. May I?" I nodded. Dorsey poured some of the Scotch into Firebird's empty water-glass and sipped it. * * * * * "The men who devised the Nuremberg Principles failed us when they forgot to underwrite the romantic aspirations of human guinea-pigs," I said. "As a result of their oversight, it seems that McQueen's Beasts have made a bigger contribution to sociology than to bacteriology. We've demonstrated that familiarity doesn't breed. Here we are, now, fourteen pairs of healthy Americans in their middle twenties, and neither a marriage nor a pregnancy amongst us. Why?" "Tell me, John," Dorsey said. "I'll tell you why," I said. "It's because we're fond of our foster-sisters, but we're also a little bored with them. And they with us. We men know every canned peach's flirtations and frailties and conversational gambits so thoroughly that one of us could no more marry one of them than the average outsider could marry his kid sister." "Even that's been done, John, just for principle's sake," Dorsey said. "The Pharaohs wed their sisters because no one else was exalted enough for the honor. Our predicament is not dissimilar. The primal urge, John, will in time overwhelm the curse of contiguity." "Could be," I said. "But it's not just sex that's agonizing me, Bud. Prison has whole constellations of frustration. However warm and understanding our guards may be, this is still a prison, and half of us are stir-crazy. Why did Mike Bohrman take off his chastity-suit last winter, to walk barefoot through the snow with only his suit-shorts on, till he collapsed from the cold? It was a prison-break, Bud. So was Mary deWitte's witless marriage. They were both suicide, the lifer's one way over the wall." "Stir-crazy?" Dorsey asked. "You're exaggerating, John." "Open your eyes, Bud," I said. "Look at Karl Fyrmeister's hands, for example. I'm violating no medical confidence to tell you that Karl got his dermatitis as the result of compulsive hand-washing. There's a fine neurotic symptom for a germ-free Lapin! If I'm exaggerating our collective un-sanity, Bud, tell me why Lucy Cashdollar has become an apprentice alcoholic. Why does Fizz Ewell, with an I.Q. that must range in the 150's and the most brilliant record the Nuclear Engineering Department has ever seen, spend six hours a day working crossword puzzles? Why do you have that tic of your left orbicularis oculi? Why am I an insomniac, with a nasty barbiturate habit? Look around, Bud. You'll see that our little home has turned into something of a snakepit. Our neuroses are only garter snakes so far; but they'll grow into cobras, given time and further frustration to feed on." * * * * * Dorsey's left eye twitched as though my mentioning his tic had triggered it. He self-consciously raised his fingers to the vellicating muscle, more to hide than to soothe it. "While our keepers were sending Lapins through every major discipline offered on the campus," he said, "it seems they'd have done well to have trained one of us in psychiatry." "For what?" I demanded. "So we could have someone right here in the Tank to spoon out our soothing-syrups? Man, we've got a right to be stir-crazy. We're life prisoners and we've committed no crime." I stopped to get my calm back. "Bud," I asked, "do you know what I want more than anything else, next to Anne?" "Of course I do," Dorsey said. "Like you've pointed out, John, we've got no secrets from each other. Your big itch is to step aboard one of the Orion ships. You want to join up for the chase after interplanetary white whales." "It's only natural," I said. "When we were kids, Bud, we saw the same TV programs, the same space-adventure movies, as the kids who are now the men in space. Every boy in America was conditioned to long for a space-suit. I'm one of the ones who could have made it, Bud. I love medicine, and I think I'm going to be a damned fine pathologist; but I'd turn in my M.D. for an Ordinary Spaceman's ticket without a second's hesitation. When I read, two years ago, that Immermann had discovered that human skull in the oxide rubble below Roosevelt Ridge in Syrtis Major, I cried for the first time since I was six years old. Twenty thousand years ago there was man on Mars. And I'm confined to Earth for life." "How much do you know about the Immermann skull, John?" Dorsey asked me. "What I've said. Is there more?" "One point," Dorsey said. "My field, radio astronomy, is a deep-space sort of specialty; but I do from time to time condescend to read the _Journal of Aerology_ and the other parochial, solar-system publications. Somewhere I read that there's something odd about that skull Colonel Immermann dug up." "If you're suggesting that it was a second Piltdown hoax, planted in that Martian talus to jar larger Air Force appropriations from Congress, keep it from me," I said. "I cherish the illusion that the Immermann is genuine, and a mystery." * * * * * "It isn't phony, and it's sure as hell a mystery," Dorsey said. "Colonel Immermann's initial report of the skull's discovery was verified by every member of the _Orion Gamma's_ crew, a gang recruited mostly from Service-Academy grads and other high moral types. The peculiarity I'm talking about isn't forensic. It's functional. If you were to mix in the Immermann skull with an assortment of skulls of modern western men, age forty or thereabouts, only one characteristic would allow you to pick it out from the mixture again. 'Look, Mom--No Cavities!' Like us Lapins, Immermann Man had acarious teeth." "Because he was germ-free?" I suggested. "It's possible. Or his medical science may have gotten oral bacteria under control with drugs. Maybe he preserved his teeth by diet, or with fluorides in his drinking-water. Perhaps his mother never let him eat candy when he was a kid," Dorsey said. "Who knows? Good teeth and all, though, our Immermann Man died twenty thousand years ago. Why? Was he germ-free, as you suggest; and was he killed by some species of Martian micro-organism that's since gone extinct from drought and a shortage of hosts? The big question, to my mind, is why none of our explorers has yet found any sign of the rest of the expedition." "Expedition?" I asked. "A man could hardly have been alone on Mars," Dorsey said. "From where?" "Pick any 'F'- or 'G'-type star with planets," Dorsey said. "After all, it's easier to posit extra-solar man than to suppose a flint-drive spaceship was devised by some early neolithic von Brauns." "I'd never expected to see an astrophysicist take off on such a flight of improbabilia," I said. "John, would you like to hear a thread-recording I just got from the radio observatory at Adelaide?" Dorsey asked. "Hi-fi?" "The radio sky is strictly spark-gap quality, no fi at all," Dorsey said, getting up to lead the way from the dining-room. "This transmission you're going to hear doesn't have anything to do with the ordinary 21.12-centimeter neutral-hydrogen radiation; but of course you realize that our big paraboloid bowls can catch anything from hydrogen hiss to low-flying bats. Remember the Christmas celebration at New Caanan that was telecast to earth a couple years back? That show was caught by the six-hundred-foot receiver at Green Bank, West Virginia, and rebroadcast by C.B.S." * * * * * We entered the Big Tank's common room, where a few of our colleagues sat reading or writing notes for tomorrow's classes--talking; playing chess or bridge; or sitting behind the closed glass doors of the TV alcove watching the picture through stereo spectacles. We entered the alcove at the other end of the room, where the record-player and music library were, and closed the door. Dorsey took a three-inch spool of magnetic thread from his shirt pocket and fit it to the playback head of the machine. "I'm interested in your uninstructed reaction, John," he said. "So don't ask me any questions till you've heard the whole sequence." "Spin it, professor," I said. The Australian thread had a noisy background, sounding like a dozen rashers of bacon tossed into a too-hot skillet. Over this hissing, the code began to sound. "DIT ... DIT ... DIT-DIT ... DIT-DIT-DIT-DIT ... DIT-DIT-DIT ... DIT-DIT-DIT-DIT-DIT-DIT-DIT-DIT-DIT ... DIT-DIT-DIT-DIT...." I dutifully entered my count of each burst of DIT's in my pocket notebook. The sequence went: 1, 1; 2, 4; 3, 9; 4, 16; 5, 25; 6, 36; then 5, 2, 49; 8, 64. There the count stopped climbing and commenced again with the pair of ones, to repeat the whole set again. Dorsey cut off the machine. "I've got four hours of the same thing on this thread," he said. "Want to hear it all, or have you got it already?" "It's obvious, up to a point," I asked. "It's a table of the first eight natural integers and their squares, except for the number seven, which for some reason is split in two." "It took me quite a while to recognize what happened to that seven," Dorsey said. "Listen to it again." He spooled the thread back and I listened again to the fractured seven: "DIT-DIT-DIT-DIT-DIT ... DIT-DIT." Then again the forty-nine clicks, seven-squared. Dorsey switched off the player. "Let's have the distillate of your cerebrations now, Brother Bogardus," he said, dropping into the deep, red-leather easy chair beside the thread-player. "It's syncopation, Brother Dorsey," I said. "I'd never have given my own modest observations so high-flown a title," Dorsey said. "I'd simply have called it, country boy at heart that I am, 'Shave-and-a-Haircut, two-bits!'" "So it is," I said. "Now we've deciphered that broadcast, and listened to the singing commercial. But I'm still puzzled, Bud. We don't have the sponsor's name and address; and I'm not at all sure I caught the name of his product. What's he advertising?" "His presence," Dorsey said. "I interpret the message as a simple CQ." "Seek you?" I asked. "Yes. Radio-ham code for, I'm lonely--will somebody please talk to me?'" * * * * * "I'll accept that interpretation only till I can think of one even more fantastic," I said. "O.K., John," Dorsey said. "Getting the address of the station was a simple exercise, thanks to my Digger confreres in Adelaide and the men at Harvard's South African radio observatory. We first heard the message two years ago. It's still being broadcast, unchanged. The fist on the key that sent out our arithmetic message belongs to someone in the neighbourhood of Alpha Centauri." "Hot damn!" I said. "But why didn't I know about this? I read _Time_, and all. Why wasn't this headlined?" "Because it's guesswork," Dorsey explained. "This may be the result of some cosmic coincidence as unrelated to intelligent planning as Bode's Law." "You'll have to explain that to this groundsman," I said. "Bode's law, too, looks like an intelligently devised code of some sort," Dorsey said. "Take the series: 0, 3, 6, 12, 24, 48, 96, 192. Add 4 to each number, and divide by ten. The result will be, when you take the asteroid belt into consideration and fudge a little, very nearly the proportional distance from the sun of the first seven planets. Accident, or evidence of intelligent planning? Turned out there are excellent physical reasons for this relationship, reasons old Johann Elert Bode couldn't possibly have guessed. Things like this make astronomers leary of teleology. Make them avoid the splendid guess." "Go ahead, make a splendid guess," I said. "I won't report you to the Astronomers Union." "Sure," Dorsey said. "Alpha Centauri, as the U. Cal's five-meter Luna 'scope demonstrated several years ago, has a system of at least three planets. We don't know much about those planets except their time of revolution." "And that one of them has a citizen clever enough to calculate natural squares and build a radio transmitter...." "... one hell of a transmitter!" Dorsey said. "... and whistle, 'Shave and a Haircut, Two Bits,'" I went on; "which musical interlude argues for a certain degree of conviviality on the part of our Centaurian. This thing of his message, though. Do you think he was just looking for other hams to talk with?" * * * * * "Then he's awfully patient, sending out the same 'CQ' for two solid years," Dorsey said. "It's hardly practical to communicate between stars, John. Broadcasting from here to Alpha C. and back, it would take more than nine years just to ask how's the wife and kids. "The way it looks to me, our friend out there got the duty of cutting an educational recording to be broadcast automatically to the rest of the galaxy. Kind of a lighthouse, to help his race get in touch with any relatives it might have. That same recording has been played over and over again ever since, sending To Whom It Might Concern its dual message. Simple math--and the most persistent rhythmical cliche known to man." "What's being done about it?" I asked. "We've answered," Dorsey said. "A big radio noise on the moon is broadcasting the same message, minus the syncopation, and adding the next two terms; all this beamed toward Alpha Centauri. And two years ago, the Defense Department cut other programs to the bone to start construction of _Orion Zeta_, the sixth of the big nuclear-pulse ships. She's up in von Weizsäcker Crater on the back of the moon now, John, nearly finished. She's not meant to call at solar-system ports." "The government thinks, and you think, that our operator four and a half light-years from here was human," I said. "I can't speak for the government. But that's what I think. Isn't it human to toss notes out to sea in bottles? What's more human than dropping a joke into an arithmetical table?" "All we've got to do to prove your splendid guess is to highjack a germ-free spaceship," I said. "You and me and any of the other Lapins who feel as we do. We'll go shake the hand--or other prehensile member, if he's not human after all--of our Centaurian thread-jockey. What's to keep our feet in the mud, when our heads are 'way the hell out in a southern constellation?" "I gather, Herr Doktor, that you jest," Dorsey said. "If you were serious, I'd point out one minor flaw in your blueprint for adventure. It would take our little band of pirates one hundred twenty-five years to get to Alpha Centauri, after we'd stolen the ship. That's with the gas-pedal to the floor." "I was joking," I said. "I was pretending to be the hero of one of those TV space-operas we used to watch.... But if I were serious, I don't think a mere century and a quarter would faze me. We couldn't reach our goal in person, Bud; but we could send our children's children. All we'd need to make the trip, if I were serious about my suggestion, would be a few more volunteers. A proper proportion of those volunteers had best be philoprogenitive females." * * * * * "Do you think the BICUSPID brass will be happy to see its expensive guinea-pigs taking off into space?" Dorsey asked. "Since '29, John, there's been eighty million bucks poured into gnotobiotics here at Central University. We're the payoff. We can hardly expect Dr. McQueen to stand on the launching-pad, tossing roses and shouting Bon Voyage as we blast off forever." "I think they could be persuaded to be, if not enthusiastic, at least resigned to our departure," I said. "It does prisoners good to plot escape-plans, even when they're as obviously fantastic as this one," Dorsey said. "Go on, John." "As you say, our purpose in this adventure would be to escape," I said. "There's no place on earth that can take us, so we're forced to escape into space. We'll have to talk this up around the Big Tank to see how many want to break out with us. What the sex-distribution of the volunteers is, whether we've got the right range of specialists to man a spaceship. Right, Bud?" "It's your dream," Dorsey said. "O.K. Immermann Man appears to have been germ-free," I said. "Perhaps his culture had been gnotobiotic for so long that they'd forgotten the existence of micro-organisms. Landing on other planets, they'd not rediscover the danger of infectious disease till it was too late. Suddenly they'd start falling, dying of illnesses as mysterious to them as the plague was to men of the Renaissance. This may have been the manner in which the original owner of the Immermann skull died, on Mars. We have a reasonable suspicion that there was germ-free human life in our corner of the galaxy twenty thousand years ago. Perhaps, as you suggested, these visitors were members of an exploration party. From Alpha Centauri? Is our ham who hammered out the table-of-squares a member of that gnotobiotic race? Is he our brother in purity?" "Go on, Johnny," Dorsey said. "You ain't even winded, yet." "The _Orion Zeta_ is being built for deep space," I went on. "Some group from earth is certain to set out in her on the four-generation hop to Alpha Centauri. Would it be morally right to allow this group of ambassadors to be made up of 'normal,' contaminated humans? To carry to a possibly defenceless population a mixed bag of goodies like _Micrococcus ureae_, _Bacillus vulgaris_, _Staphylococcus aureus_, _Mycobacterium tuberculosis_--a whole spectrum of benign and malignant bacteria? Remember, Bud, bugs that are benign or only mildly pernicious on earth might prove to be killers away from home." "Lots of maybes," Dorsey said. "Lots of perhapses." * * * * * "I've got one more shaft in the quiver," I said. "This one's got a poisoned point, and it carries the names of our keepers. It's dirty, Bud. It's hardly fair to Dr. McQueen to use such blackmail." "Blackmail sounds like just what we need," Dorsey said. "O.K. Thirty of us were born into the Big Tank," I said. "One has already died as a result of his mental state, caused by imprisonment. Another is certain to die within the next few days. Had they been entirely sane, Mike Bohrman and Mary deWitte wouldn't have shed their sterility-suits outside the Tank. Without purpose to their lives, they cracked up. "Two of us dead in the first twenty-six years of the human studies at BICUSPID," I went on. "Two, out of an original thirty. An attrition-rate of six and seven-tenths percent. How many more Lapins will wander out to commit innocent suicide in the snow, their minds messed up by the frustration and hopelessness of the guinea-pig way of life? How many more of us will escape from the Big Tank into the morgue? The _Orion Zeta_ could be our salvation, Bud. It could give us the sort of purpose human beings must have in order to live." Dorsey shook his head. "The Defense Department set up its young Clydeside in von Weizsäcker Crater just to build, test, and launch one ship: the _Zeta_. Two years of round-the-chronometer work have been poured into her," he said. "She's cost four billion dollars so far, Johnny; and they haven't bought the living-room furniture yet. I hardly think the generals will volunteer the result of all this effort to serve as psychotherapy for twenty-eight neurotic Hoosiers." "You miss the point, Bud," I said. "We Lapins were born to crew the _Zeta_. Where else could you find a crew that's already spent twenty-odd years or so inside a box, living together in close quarters, being conditioned against claustrophobia? This Big Tank of ours could be a grounded spaceship, Bud! It's airtight, armored against outside dangers, even has the formaldehyde sump to serve us for airlock. What's a sterility-suit, anyway, but a special breed of space suit? Could you find a better crew than us twenty-eight, skilled in two dozen professions, young, sound of wind and limb, and willing as hell to take on the job? None of whom will ever have appendicitis, halitosis, toothache, barber's itch, or athlete's foot? Any one of whom can, in case of accident, first-aid his wounds with a spit-damp handkerchief, and heal wholesome? Man, we're what those generals have been dreaming of! Once we've been trained to aim that big ship and kick her off the back of the moon, we'll be the finest extra-solar crew that ever blasted free of the system!" "One question," Dorsey said. "Where do I sign Ship's Articles?" * * * * * Dr. McQueen was in Chicago for three days before he found Mary Lofting, née deWitte. She had wakened that morning suffering from a headache, a stiff neck, and four degrees of fever. Her husband had called an ambulance to take her to Michael Reese Hospital. There, just before she'd lost consciousness, Mary had asked a nurse to call BICUSPID. The C.U. authorities had in turn called Dr. McQueen in Chicago. She came home on a stretcher, a bottle of fructose solution dripping into her veins. Mary had already been loaded with a double-barreled shotgun-blast of every antibiotic she could safely take. Dr. McQueen rode back to the University in the ambulance with her, and with her husband. Lofting, holding the girl's hand, explained time after time that she'd never told him about the likely consequence of her removing her chastity-suit in an un-chaste world. The basketball player said he'd never forgive himself if she didn't recover. Mary was taken to the C.U. hospital. Wearing a sterility-suit, I attended her examination, which was conducted by my chief-of-service, the staff pathologist, as well as the hospital's internist and neurologist. I took a few cc's of Mary's cerebrospinal fluid back with me to the BICUSPID contaminated labs. There, to anticipate a few days' deliberate bacterial growth in media, her meningoencephalitis was discovered to have been caused by _Erysipelothrix monocytogenes_, an organism whose more usual victims are rabbits. Mary's husband could explain her coming in contact with so exotic a pathogen only by the fact that they'd visited the Brookfield Zoo on the second, and last, day of their honeymoon. By the time these technical details were known they were academic. The epidemiological problem had become secondary to the pathological. Mary Lofting had died. I was asked to assist Dr. McQueen and the senior pathologist at autopsy--I was, after all, a resident in pathology, and had besides a special interest in this case--but I found the job more than I could take. Mary had been a sister to me for twenty-three years. In tears, I left the morgue during the classic cruciform incision. * * * * * I found the Firebird in the library. I recognized her through the anonymity of her chastity-suit by the characteristic pose of her head and arms as she sat reading: elbow braced on the table-top, her right fist blocked stubbornly against the plastic cheek of her helmet, her left arm curved around the book as though to be a break-water against distraction. I sat beside her, and said, "Dorothy." Without a word she closed her book, stood, and replaced it on the shelf. We walked hand in hand out into the autumn campus. "Last year," I said, "it was Mike Bohrman, walking through snow-drifts in his suit-shorts, wanting for once in his life to feel the real world against his skin. So _he_ died. Five days ago, Mary deWitte married the man she loved. So she died," I said. "Our life isn't generally as hopeless as that," the Firebird said. "No," I said. "We're fed and entertained. We're being educated at one of the finest universities in the world--for us, she's been a genuine, homogenized-milk Alma Momma. She even gives us an allowance to buy airmail stamps for our collection, or bar-bells, or gas for our sports-car. She's given us everything we need for happiness. Everything, Firebird, but purpose. That's why we're all going nuts--why Mike went barefoot in the snow and Mary used love for a suicide-weapon. That's why we've got to break free." "Free?" she asked. "You mean, free to step outside the Big Tank, shed our sterility-suits, turn septic--and die?" "I mean free to step off earth." We sat by mutual consent on a bench beneath a sugar maple, brushing aside half an inch of multicolored leaves. I told the Firebird of the broadcast from a southern star, and about the Immermann skull. I told her all I knew about the Orion rockets, the nuclear-pulse ships that had gone through five prototypes to reach the _Zeta_. "She's built to travel light-years," I said. "I'm going with her when she leaves." "Of course, I'm going with you," she said. "Your spacemen will need a dietitian to make metabolic sense out of algal soups and hydroponic salads for the first couple of generations, and to teach the youngsters to take over the kitchen once they're on their own." "Firebird," I said, "I'm happy to welcome you aboard. Now we've got to get that ship." "We'll get it," she said. "Understand, Johnny, it's not the professional challenge that makes me want to blast off for Alpha Centauri with four generations to feed. I've got no special urge to tame frontiers. The reason I'm going--forgive me for mentioning it again, and cold sober--is to stay near you." I stood up, drawing her up after me, and was struck again by the aptness of the nickname, "chastity-suit." "Perhaps I've overestimated the effectiveness of a certain taboo," I said. "Come on, sweet Firebird. Let's get back to the Tank to help Bud recruit the rest of our crew." * * * * * Colonel Barrett was young for eagles. My fellow volunteers-designate and I, all twenty-eight of us, were gathered in the lounge of English Hall, creaking and wheezing in our sterility-suits, looking very ready for hard space. The colonel wore crisp blues. His tunic was decorated by a triple row of medals-for-merit. It was not his fault that he wore no battle-stars. Barrett had graduated from the Air Academy into our seemingly endless _Pax Desperandum_. He'd never had a chance to see a roentgen radiated in anger. The Marsman Badge at the center of his left breast pocket was one rarely seen: the circle-with-arrow symbol of Mars had within it a "III," signifying that its wearer had been a member of the Third Mars Expedition, back in the days when a flight to Mars had been something more than a teamster's run. The Marsman Badge was balanced by the star-topped, laurel-wreathed--and anachronistic--silver wings of a Command Pilot. As I shook hands with Colonel Barrett I found it difficult to conceal the envy that writhed in me. He'd seen the continents spread cloud-flecked on the receding, curving earth, the stars shining beside the sun against the black sky. He'd splashed across the dust-carpet of the moon, tasted water melted from the polar cap of Mars. As a member of Expedition Three, he'd been with the crew of the _Orion Gamma_ when Immermann discovered the twenty-thousand-year-old skull at the base of Roosevelt Ridge. Colonel Barrett addressed his remarks to me. "Central University," he said, "will lose the results of an eighty-million-dollar investment if you people leave. They'll be getting off cheap, compared to us. The Defense Department has been requested to turn over to you twenty-eight untrained grounds-men the greatest spaceship yet built, the first of the interstellar ships. The _Zeta_ cost the taxpayers four dollars a pound to build. She weighs five hundred thousand tons, Dr. Bogardus." "You're mistaken, Colonel, when you say that the University's investments in gnotobiotic research over the past eighty years will be lost if we Lapins end our part of the experiment. That's not true. That investment has been repaid many times over. More has been learned of human physiology, nutrition, and disease processes in the twenty-six years' study of germ-free humans than was learned concerning these subjects during any similar period in medical history. "And, Colonel," I went on, "we're not untrained. Bud Dorsey, to your right, is an astrophysicist who worked with the Agassiz Observatory team in mapping the interstellar anti-matter dust clouds. Dr. Keto Hannamuri is a pediatrician. Dorothy Damien, our Firebird, is a dietitian. Fizz Ewell is a nuclear engineer. Karl Fyrmeister's degree is in chem engineering, as is Janie Bohrman's. Gloria Moss is working on her doctorate in sociology. Her thesis, Colonel, deals with the social dynamics of small human groups such as ours. Alfred MacCoy, standing behind you, has written three symphonies and an oratorio so far; and R.C.A. Victor has threaded them all with the New York Philharmonic. Lucy Cashdollar has had her works of sculpture displayed in the National Gallery and at London's Tate. There are some few resources here, Colonel." "I didn't intend to belittle your intellectual accomplishments, Dr. Bogardus," the Colonel said. "I've read your dossiers. They're impressive. When I called you untrained, what I really meant was that you're totally unskilled in terms of my own specialty. I meant that none of you knows anything of the skills of simple chemical rocketry, much less the techniques required to lift half a million tons on a nuclear-pulse thrust." "We can learn," I said. "I hope so," Colonel Barrett said, "because I've been ordered to teach you." * * * * * "We're in?" Bud Dorsey demanded. "You're in," Colonel Barrett said. "The decision in the Pentagon went against my recommendation that professionals in rocketry be recruited for the Alpha Centauri flight. The generals liked your argument, Dr. Bogardus, that we should send a germ-free ship and a germ-free crew to a possibly germ-free planet. In a sense, this is tradition. Back in the '50s, moon-missiles were sponged down with Lysol before launching, just in case they got where they were aimed at. Our people didn't want to contaminate the moon's surface with earthly micro-organisms, cluttering up the picture for the bacteriologists who were scheduled to arrive later. The Chief of Staff said that if there is a germ-free population on one of the Centaurus planets, we must not initiate our contact with them by handing out the sort of prizes Cook's crew brought to the South Seas--measles, tuberculosis, smallpox. We can't know that even innocuous bacteria might not be fatal to a gnotobiotic, alien population. So you go." "Colonel," I said, "I'm sure that Washington didn't give up the _Zeta_ to us out of sheer altruism. What's their real reason?" "Where else could we get a crew of twenty-eight men and women who've given proof they can live together for a long period of time, peaceably, retaining a fair degree of sanity? Miss Moss's studies in group dynamics were most interesting to the Chief of Staff. Doubtless they did much to influence his decision in your favor." "There's one thing I don't understand, Colonel Barrett." "What's that, Miss Damien?" he asked. "Why is it that you seem so unhappy about our being accepted as the _Zeta's_ crew?" she asked. "After all, you've been given the duty of training us to take her between stars. That's a pretty important assignment, isn't it, even for a bird colonel?" "You're right, Miss Damien," Colonel Barrett said. "My new assignment is a vital one. You must forgive me if I seemed curt and unfriendly." He paused. "I've been trying to hide my feelings, but evidently I failed. You see, Miss Damien, my wife and I had headed the previous list of volunteers--the contaminated crew." * * * * * Looking from the ports of the rocket that had brought us from Memorial Orbital Station, I'd thought von Weizsäcker Crater the most impressive sight I'd ever seen. The _Orion Zeta_ looked from our height like nothing so much as a miniature silver cocktail-shaker, glinting at the center of the vast circle of von Weizsäcker. Later, standing a few hundred feet from _Zeta's_ base, I'd found the order of impressiveness reversed. The great ship was a tower of fifteen hundred feet, blacking out the stars like a geometric mountain; while the crater's twenty-thousand-foot ringwall, so far away in all directions, was no more obtrusive than a decorative hedge. This ship, I thought, is the intelligent comet on which we'd be passengers until the day we died, some two and a fraction light-years away from home. We were guaranteed immortality, though, in our offspring. Our descendants would very literally become flesh of our flesh, bone of our bone, as our bodies were resurrected to vegetable life in the hydroponic tanks of the ship. We Lapins clustered close together on the moon-dust, staring up the sides of our ship. Her upper reaches were hidden by the globular bulge of the enormous thrust-chamber, where kiloton capsules of nuclear fuel would be fired, three a second, to blast us into space. In this great ship our children would be born and would die, and our grandchildren as well. From the _Zeta_, our aged great-grandchildren, limping down long ladderways to the exit-hatches on the arms of their teen-aged grandsons, would step onto the soil of a planet that circled Alpha Centauri. One hundred and twenty-five years from now, I thought, clasping the Firebird's hand in mine. So little in history, so big in human lives! One hundred and twenty-five years ago, the Brooklyn Bridge had been brand-new. U.S. Grant, defrauded and cancer-ridden, was gritting his teeth against the pain to write his memoirs. President Chester A. Arthur had just signed into law a bill prohibiting polygamy in the territories. As far away as those things lay our goal. We entered the sublunarian chambers beneath the ship. Dr. McQueen had preceded us here; and under his direction the _Orion Zeta_ had been made as aseptic as the Big Tank itself. Colonel Barrett and his subordinates who'd train us to operate the _Zeta_ would have to wear sterility-suits aboard her, and would enter through the formaldehyde sump that was now her only entrance. Even the dust of the moon was not entirely sterile. The Firebird took my arm to urge me toward the liquid gateway to the ship, eager to see our new home. "Wait," I said, holding her back till all the others had gone through the antiseptic pool. "Cold feet, Johnny?" she teased me. "Gloria Moss once told me, Firebird, that a healthy respect for tradition is essential to the organic strength of a group such as ours," I said. "So...." I bent and picked the Firebird up, her weight moon-trimmed to that of a three-year-old. She put her arms around my neck as I carried her down the ladder into the poisonous decontamination tank that was our front door to Alpha Centauri. 
59304	----	BRIGHT ISLANDS BY FRANK RILEY _The future enters into us, in order to transform itself in us, long before it happens._--RAINER MARIA RILKE [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, June 1955. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] When the two Geno-Doctors were gone, Miryam took the red capsule from under the base of the bedlamp and slipped it between her dry lips. Reason told her to swallow the capsule quickly, but instead she held it under her tongue, clinging, against her will, to the last few moments of life. She knew she was being weak, that she was still seeking hope where there was no hope, and she prayed to the ancient God of the Ghetto that the gelatin coating would dissolve quickly. Pain interrupted the prayer, spreading like slow fire from deep within her young body, where the unwanted child of Genetics Center stirred so restlessly, so impatient to be born. The white walls of her Center room blurred in and out of focus. Shadows merged together in brief, uncertain patterns. Lights flickered where there were no lights, and the darkness was so intense it had a glare of its own. At the worst of the pain cycle, Miryam bit down on her under lip until the flesh showed as white as her teeth. She fought off temptation to crunch the capsule and put an end to all pain, all fear. No, she would not go that way. She would go in a moment of blinding clarity, knowing why, savoring the last bitter sweet second of her triumph. With a subconscious gesture of femininity, Miryam brushed the dark, damp hair from her forehead, and wiped the perspiration from her lips. "Pretty little thing," one of the Geno-Service agents had called her, when she was arrested last fall in the Warsaw suburb where she had taught nursery school since escaping from the Ghetto. "Doesn't look a bit like one of her kind," another agent had said, putting his hand under her chin and turning her face to the glare of his flashlight. "No wonder she fooled the Psycho and Chemico squads.... Lucky for us!" "What's the matter, little one?" the first agent had spoken again. "Didn't you know we were coming? I thought all of you people were supposed to be telepaths.... Or doesn't it work when you're asleep?" He flipped the covers off her trembling body and whistled. "Hands off!" the Geno-Sergeant had warned sharply. "She's for Center!" Now the capsule under her tongue was moist and soft. Time fled on swift, fluttering wings. Soon the horror would be done. But the stubborn spark still glowed, and Miryam allowed her mind to drift down the long, shining corridor to the room where the younger of the two Geno-Doctors was changing into a white coat. The older man, who wore the gold trefoil of Geno-Sar on his collar, tilted back in his chair. "She should be just about due," he said cheerfully. "Yes, Sir," replied the young doctor, sounding the proper note of deference for a man who communed daily with the political elite. "What do you think of her?" "Well, Sir, frankly--I was surprised--" The young doctor twisted muscular arms to button the back of his jacket. He had but recently come from the Genetics Sanitarium on the Black Sea, and his face was tanned deep brown. "From reading the weekly reports of your staff, I didn't know she was that--that young--" Miryam trembled with a hope she dared not recognize, but it was crushed out of her by the Geno-Sar's booming voice. "Not only one of the youngest--but one of the very best specimens we've had to work with at Center! You read her psi rating?" "Yes, Sir. Seventy-two point four, wasn't it?" "Seventy-two point six! Absolutely phenomenal! Closest thing to a pure telepath our agents have ever turned up for us! This could be a big night for Center, my boy.... A big night!" The young doctor shook his head to clear away the lingering image of a tragic, lovely face against a tear-stained pillow. Miryam was startled to find this image in his mind, and her pulse leaped again. In a carefully professional tone, the young doctor asked: "What was her rating after insemination? Did the emotional shock...?" "Not at all! Oh, naturally, she was uncooperative in the tests, but pentathol and our cross-references gave us a true picture!" "And the spermatozoa?" "Best we could get! Refrigerated about thirty years ago from a specimen that tested forty-seven point eight." The Geno-Sar paused, and because a comment was obviously in order, the young doctor said: "This certainly could be a big night for Center!" The Geno-Sar snapped his cigarette lighter with an expansive flourish. "All the sciences have been taking a crack at psi--ever since the last Politbureau directive gave it number one priority. You should have heard the talk at Sar-Bureau meeting this afternoon! The Math-Sar actually laughed at Genetics ... told us to stick to our white mice!" The young doctor made a polite cluck of disapproval. "Those stupid mathematicians could learn something of heredity from their own ancients," the Geno-Sar continued, growing heated. "Think of Liebnitz, gifted at 14--Galois, a genius before he was 21!" The Geno-Sar recovered his temper, and winked. "Of course, I didn't say that at the meeting--the Bureau chief is very partial to Math--but I did remind them, most pointedly, of the known data on inherited sensory differences between individuals. And you should have seen the squirming! Especially when I got into the taste studies and the phenyl-thio-carbamide tests! Then, when I told of Genetics research on sense of time--sense of direction--sensitivity to pain, sound and smells--Well, the Chief was hanging on my every word! The Psycho-Sar became desperate to the point of rashness, and he jibed at me about our ancient master, Profim Lysenko." The Geno-Sar's head inclined slightly as he pronounced the name. "But the Chief himself gave the correct answer! He quoted from a Bureau directive which stated clearly that sensory characteristics, like any others, could well have been acquired in the first place, and then passed on through heredity! Oh, I tell you, it was a heart-warming afternoon!" The younger man had been paying him only half attention. "It's strange we should find some cases of psi among her people," he mused. "When I was at the University I always meant to study something about the--" he hesitated and searched for the approved term, "--the specimen races, but I never had time...." For an instant the Geno-Sar's steel-blue eyes narrowed, and Miryam was shocked to find him appraising the young man for possible heresy. She had always regarded the scientific mind as something remote, cold, but never as something that could commit a heresy. However, the Geno-Sar decided to table the subject. "Of course you didn't!" he boomed. "You couldn't have made such a splendid record without total specialization! Each to his own, that's how science has prospered under the benevolence of our party!" He glanced up at the clock. "Well, aren't we just about ready for this delivery?" * * * * * Miryam drew back her mind. What a fool she was to go on seeking! The child resumed its inexorable turning within her swollen body, and she knew she could never give to the world a life conceived so terribly, so coldly, without love or passion or tenderness. Even in these final moments, with the gelatin melting under her tongue, Miryam shuddered with the remembered anguish of struggling up from the depths of anaesthesia to find herself bearing the seed of a child, from a faceless man who had died long ago. Often, during the carefully guarded months of pregnancy, she had wondered about that man, who he had been, how his talent had compared with hers. Miryam knew little about genetics, or any other science. The scientific mind had always frightened her, and she had feared to explore it. But she knew there was no truth to the folklore that psi was a characteristic of her people. She knew of only a few cases outside her own family, although within her family it seemed to have been a characteristic that had recurred frequently for many generations. Her father had cautioned her about selecting a husband, and pleaded with her not to flee the Ghetto. For the past three days, since the nurse had momentarily left the cabinet at the end of the corridor unlocked and unguarded, Miryam had known that she need not be concerned about the success or failure of this terrible experiment. From the nurse's mind she had plucked the essential facts about the potency of the red capsule. This knowledge, for all its loneliness, had been something to cherish, to press to her full breasts, as she would never hold that child of horror. Tears filled her eyes, squeezed in droplets between the closed lids. Tears because she was so alone. Tears of unbearable sadness and pity, for her people, for her youth and her young body, for the warmth that would be eternally cold, for the unnatural child that squirmed and turned, and would never cry. In a last forlorn gesture, in a final seeking before the darkness closed, Miryam let her mind stray out of the white room, out of the marble magnificence of Center. She let her thoughts escape on the soft breeze of the early summer evening. How beautiful it was, even here in the city, amid the science buildings that formed bright islands of light around the minarets and vaulted domes of Government Square. Even these awesome buildings were lovely in the purple dusk. Their windows were like scattered emeralds of light. How could there be so much beauty without compassion? So much knowledge without understanding? So much human genius without humanity? And what a battering of thoughts in the mild air around the centers of science! What a discordance! What a tumult of theories, each of them nurtured within its own walls by the zealous Sars. There were the Departments of Chemistry and Physics. There was the glass-walled tower of Astronomy! There was the Institute of Psychology, with all its many bureaus. And the new Electronics Building, alabaster even in the dusk. They were all there, extending in stately splendor along the main avenues, and along the park, where the gossamer mist was rising. How intolerant were the thoughts they radiated! How sure! Electronics said: "Quite obviously the answer to psi is in the electrical currents of the brain. Our newest electro-encephalograph has demonstrated...." Chemistry said: "Solution to psi inevitably will be found in the chemical balance of the cells...." Parapsychology said: "We must continue to ignore those who insist upon attributing physical properties to a non-physical characteristic...." And underneath this learned babble, Miryam heard the moth-like whispering of her own people, starving in the Ghetto, or hidden throughout the city, disguised, furtive, tense. Her mind came close to Government Square, and she cringed, as she had cringed all her young life. The somatics were unbearable. Hatred and fear, blind prejudice, jealousy, cunning, ceaseless intrigue and plotting, setting Sar against Sar, using the genius of each science, dividing and ruling. No, there was nothing left. No hope, no promise. This was the end of time. This was the night of the world. Withdrawing again, retreating into itself, Miryam's mind brushed the fragment of a thought. It was a half-formed thought, more a groping, more a question, than an idea. It was delicate, fragile, a wraith and a wisp. But it came to her as clear as the note from a silver bell. Startled, she hesitated in her withdrawal, and perceived the young Geno-Doctor in the corridor near her room. He had paused by the casement window, and was staring out at the twinkling islands of light around Government Square. And as his gaze wandered moodily from Tech, to Psycho, to Chemico, to all the incandescent, isolated centers of genius, the idle speculation had formed. "Wouldn't it be an unusual view if all those bright islands were connected by strings of light...?" Once formed, the speculation had fanned the ember of a thought: "Wonder if psi will build those strings of lights?" Then the young doctor turned almost guiltily from the window to meet the Geno-Sar coming down the corridor. And he said with crisp efficiency, "I'll check out 12-A for delivery." "Good boy! I'll go on up and check the staff...." The Geno-Sar rubbed his hands together, and walked off, repeating nervously, "Two psi characteristics must be the answer--two psi--" "Maybe they are," the young doctor murmured softly. "Maybe they are...." * * * * * Delivery, Miryam thought. The life within her throbbed and prodded. There was an ebbing of pain for a moment, and in that moment she saw with the blinding clarity she had sought that this child of hers might bring new hope to the world. That psi ability might be the answer to many things for the race of mankind. What did it matter that it was conceived without love and emotion. What did it matter that she was being used as an experiment ... if this child within her could fulfill the promise. Miryam spat the soft capsule between her quivering lips. She watched it roll and bounce across the polished tile floor, toward the door. Pain returned, and its fire was warm. There were no shadows on the wall. Pain returned, and it had purpose and promise. Wonderingly, she beheld the concept that science, too, lived with fear, each science in its own Ghetto. And if the young doctor was right, if psi.... As the doctor stepped into the room, he bent over and picked up the red capsule. His thumb and forefinger felt the warmth, the moisture, and he looked long and thoughtfully into Miryam's dark, glowing eyes. His fingers shook as he wrapped the capsule in a piece of tissue and dropped it into the pocket of his white jacket. He picked up the chart from the foot of the bed. "Miryam--" His voice was not under complete control, and he began again, with an effort at lightness. "Miryam--that's a strange name. What does it mean?" "It is an ancient spelling," she whispered, her eyes deep and dark, filled with pain and wonder. "You may find it easier to call me--Mary." 
60434	----	LEARNING THEORY BY JAMES MC CONNELL _Destiny's tricks can be pretty weird sometimes. And this was one to be proud of. A cosmic joke, a witch that could make a nightmare seem tame!_ [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, December 1957. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] I am writing this because I presume He wants me to. Otherwise He would not have left paper and pencil handy for me to use. And I put the word "He" in capitals because it seems the only thing to do. If I am dead and in hell, then this is only proper. However, if I am merely a captive somewhere, then surely a little flattery won't hurt matters. As I sit here in this small room and think about it, I am impressed most of all by the suddenness of the whole thing. At one moment I was out walking in the woods near my suburban home. The next thing I knew, here I was in a small, featureless room, naked as a jaybird, with only my powers of rationalization to stand between me and insanity. When the "change" was made (whatever the change was), I was not conscious of so much as a momentary flicker between walking in the woods and being here in this room. Whoever is responsible for all of this is to be complimented--either He has developed an instantaneous anesthetic or He has solved the problem of instantaneous transportation of matter. I would prefer to think it the former, for the latter leads to too much anxiety. As I recall, I was immersed in the problem of how to teach my class in beginning psychology some of the more abstruse points of Learning Theory when the transition came. How far away life at the University seems at the moment: I must be forgiven if now I am much more concerned about where I am and how to get out of here than about how freshmen can be cajoled into understanding Hull or Tolman. Problem #1: Where am I? For an answer, I can only describe this room. It is about twenty feet square, some twelve feet high, with no windows, but with what might be a door in the middle of one of the walls. Everything is of a uniform gray color, and the walls and ceiling emit a fairly pleasant achromatic light. The walls themselves are of some hard material which might be metal since it feels slightly cool to the touch. The floor is of a softer, rubbery material that yields a little when I walk on it. Also, it has a rather "tingly" feel to it, suggesting that it may be in constant vibration. It is somewhat warmer than the walls, which is all to the good since it appears I must sleep on the floor. The only furniture in the room consists of what might be a table and what passes for a chair. They are not quite that, but they can be made to serve this purpose. On the table I found the paper and the pencil. No, let me correct myself. What I call paper is a good deal rougher and thicker than I am used to, and what I call a pencil is nothing more than a thin round stick of graphite which I have sharpened by rubbing one end of it on the table. And that is the sum of my surroundings. I wish I knew what He has done with my clothes. The suit was an old one, but I am worried about the walking boots. I was very fond of those boots--they were quite expensive and I would hate to lose them. The problem still remains to be answered, however, as to just where in the hell I am--if not in hell itself! Problem #2 is a knottier one--Why am I here? Were I subject to paranoid tendencies, I would doubtless come to the conclusion that my enemies had kidnapped me. Or perhaps that the Russians had taken such an interest in my research that they had spirited me away to some Siberian hideout and would soon appear to demand either cooperation or death. Sadly enough, I am too reality oriented. My research was highly interesting to me, and perhaps to a few other psychologists who like to dabble in esoteric problems of animal learning, but it was scarcely startling enough to warrant such attention as kidnapping. So I am left as baffled as before. Where am I, and why? And who is He? * * * * * I have decided to forego all attempts at keeping this diary according to "days" or "hours." Such units of time have no meaning in my present circumstances, for the light remains constant all the time I am awake. The human organism is not possessed of as neat an internal clock as some of the lower species. Far too many studies have shown that a human being who is isolated from all external stimulation soon loses his sense of time. So I will merely indicate breaks in the narrative and hope that He will understand that if He wasn't bright enough to leave me with my wristwatch, He couldn't expect me to keep an accurate record. Nothing much has happened. I have slept, been fed and watered, and have emptied my bladder and bowels. The food was waiting on the table when I awoke last time. I must say that He has little of the gourmet in Him. Protein balls are not my idea of a feast royal. However, they will serve to keep body and soul together (presuming, of course, that they _are_ together at the moment). But I must object to my source of liquid refreshment. The meal made me very thirsty, and I was in the process of cursing Him and everybody else when I noticed a small nipple which had appeared in the wall while I was asleep. At first I thought that perhaps Freud was right after all, and that my libido had taken over control of my imagery. Experimentation convinced me, however, that the thing was real, and that it is my present source of water. If one sucks on the thing, it delivers a slightly cool and somewhat sweetish flow of liquid. But really, it's a most undignified procedure. It's bad enough to have to sit around all day in my birthday suit. But for a full professor to have to stand on his tip-toes and suck on an artificial nipple in order to obtain water is asking a little too much. I'd complain to the Management if only I knew to whom to complain! Following eating and drinking, the call to nature became a little too strong to ignore. Now, I was adequately toilet-trained with indoor plumbing, and the absence of same is most annoying. However, there was nothing much to do but choose a corner of the room and make the best of a none too pleasant situation. (As a side-thought, I wonder if the choosing of a corner was in any way instinctive?). However, the upshot of the whole thing was my learning what is probably the purpose of the vibration of the floor. For the excreted material disappeared through the floor not too many minutes later. The process was a gradual one. Now I will be faced with all kinds of uncomfortable thoughts concerning what might possibly happen to me if I slept too long: Perhaps this is to be expected, but I find myself becoming a little paranoid after all. In attempting to solve my Problem #2, why I am here, I have begun to wonder if perhaps some of my colleagues at the University are not using me as a subject in some kind of experiment. It would be just like McCleary to dream up some fantastic kind of "human-in-isolation" experiment and use me as a pilot observer. You would think that he'd have asked my permission first. However, perhaps it's important that the subject not know what's happening to him. If so, I have one happy thought to console me. If McCleary _is_ responsible for this, he'll have to take over the teaching of my classes for the time being. And how he hates teaching Learning Theory to freshmen: You know, this place seems dreadfully quiet to me. * * * * * Suddenly I have solved two of my problems. I know both where I am and who He is. And I bless the day that I got interested in the perception of motion. I should say to begin with that the air in this room seems to have more than the usual concentration of dust particles. This didn't seem particularly noteworthy until I noticed that most of them seemed to pile up along the floor against one wall in particular. For a while I was sure that this was due to the ventilation system--perhaps there was an out-going airduct there where this particular wall was joined to the floor. However, when I went over and put my hand to the floor there, I could feel no breeze whatsoever. Yet even as I held my hand along the dividing line between the wall and the floor, dust motes covered my hand with a thin coating. I tried this same experiment everywhere else in the room to no avail. This was the only spot where the phenomenon occurred, and it occurred along the entire length of this one wall. But if ventilation was not responsible for the phenomenon, what was? All at once there popped into my mind some calculations I had made when the rocket boys had first proposed a manned satellite station. Engineers are notoriously naive when it comes to the performance of a human being in most situations, and I remembered that the problem of the perception of the satellite's rotation seemingly had been ignored by the slip-stick crowd. They had planned to rotate the doughnut-shaped satellite in order to substitute centrifugal force for the force of gravity. Thus the outer shell of the doughnut would appear to be "down" to anyone inside the thing. Apparently they had not realized that man is at least as sensitive to angular rotation as he is to variations in the pull of gravity. As I figured the problem then, if a man aboard the doughnut moved his head as much as three or four feet outwards from the center of the doughnut, he would have become fairly dizzy! Rather annoying it would have been, too, to have been hit by a wave of nausea every time one sat down in a chair. Also, as I pondered the problem, it became apparent that dust particles and the like would probably show a tendency to move in a direction opposite to the direction of the rotation, and hence pile up against any wall or such that impeded their flight. Using the behavior of the dust particles as a clue, I then climbed atop the table and leapt off. Sure enough, my head felt like a mule had kicked it by the time I landed on the floor. My hypothesis was confirmed. So I am aboard a spaceship: The thought is incredible, but in a strange way comforting. At least now I can postpone worrying about heaven and hell--and somehow I find the idea of being in a spaceship much more to the liking of a confirmed agnostic. I suppose I owe McCleary an apology--I should have known he would never have put himself in a position where he would have to teach freshmen all about learning: And, of course, I know who "He" is. Or rather, I know who He _isn't_, which is something else again. Surely, though, I can no longer think of Him as being human. Whether I should be consoled at this or not, I have no way of telling. I still have no notion of _why_ I am here, however, nor why this alien chose to pick me of all people to pay a visit to His spaceship. What possible use could I be? Surely if He were interested in making contact with the human race, He would have spirited away a politician. After all, that's what politicians are for! Since there has been no effort made to communicate with me, however, I must reluctantly give up any cherished hopes that His purpose is that of making contact with _genus homo_. Or perhaps He's a galactic scientist of some kind, a biologist of sorts, out gathering specimens. Now, that's a particularly nasty thought. What if He turned out to be a physiologist, interested in cutting me open eventually, to see what makes me tick? Will my innards be smeared over a glass slide for scores of youthful Hims to peer at under a microscope? Brrrr! I don't mind giving my life to Science, but I'd rather do it a little at a time. If you don't mind, I think I'll go do a little repressing for a while. * * * * * Good God! I should have known it! Destiny will play her little tricks, and all jokes have their cosmic angles. He is a _psychologist_! Had I given it due consideration, I would have realized that whenever you come across a new species, you worry about behavior first, physiology second. So I have received the ultimate insult--or the ultimate compliment. I don't know which. I have become a specimen for an alien psychologist! This thought first occurred to me when I awoke after my latest sleep (which was filled, I must admit, with most frightening dreams). It was immediately obvious that something about the room had changed. Almost at once I noticed that one of the walls now had a lever of some kind protruding from it, and to one side of the lever, a small hole in the wall with a container beneath the hole. I wandered over to the lever, inspected it a few moments, then accidentally depressed the thing. At once there came a loud clicking noise, and a protein ball popped out of the hole and fell into the container. For just a moment a frown crossed my brow. This seemed somehow so strangely familiar. Then, all at once, I burst into wild laughter. The room had been changed into a gigantic Skinner Box! For years I had been studying animal learning by putting white rats in a Skinner Box and following the changes in the rats' behavior. The rats had to learn to press the lever in order to get a pellet of food, which was delivered to them through just such an apparatus as is now affixed to the wall of my cell. And now, after all of these years, and after all of the learning studies I had done, to find myself trapped like a rat in a Skinner Box! Perhaps this was hell after all, I told myself, and the Lord High Executioner's admonition to "let the punishment fit the crime" was being followed. Frankly, this sudden turn of events has left me more than a little shaken. * * * * * I seem to be performing according to theory. It didn't take me long to discover that pressing the lever would give me food some of the time, while at other times all I got was the click and no protein ball. It appears that approximately every twelve hours the thing delivers me a random number of protein balls--the number has varied from five to fifteen so far. I never know ahead of time how many pellets--I mean protein balls--the apparatus will deliver, and it spews them out intermittently. Sometimes I have to press the lever a dozen times or so before it will give me anything, while at other times it gives me one ball for each press. Since I don't have a watch on me, I am never quite sure when the twelve hours have passed, so I stomp over to the lever and press it every few minutes when I think it's getting close to time to be fed. Just like my rats always did. And since the pellets are small and I never get enough of them, occassionally I find myself banging away on the lever with all the compulsion of a stupid animal. But I missed the feeding time once and almost starved to death (so it seemed) before the lever delivered food the next time. About the only consolation to my wounded pride is that at this rate of starvation, I'll lose my bay window in short order. At least He doesn't seem to be fattening me up for the kill. Or maybe he just likes lean meat! * * * * * I have been promoted. Apparently He in His infinite alien wisdom has decided that I'm intelligent enough to handle the Skinner-type apparatus, so I've been promoted to solving a maze. Can you picture the irony of the situation? All of the classic Learning Theory methodology is practically being thrown in my face. If only I could communicate with Him! I don't mind being subjected to tests nearly as much as I mind being underestimated. Why, I can solve puzzles hundreds of times more complex than what He's throwing at me. But how can I tell Him? As it turns out, the maze is much like our standard T-mazes, and is not too difficult to learn. It's a rather long one, true, with some 23 choice points along the way. I spent the better part of half an hour wandering through the thing the first time I found myself in it. Surprisingly enough, I didn't realize the first time out what I was in, so I made no conscious attempt to memorize the correct turns. It wasn't until I reached the final turn and found food waiting for me that I recognized what I was expected to do. The next time through the maze my performance was a good deal better, and I was able to turn in a perfect performance in not too long a time. However, it does not do my ego any good to realize that my own white rats could have learned the maze a little sooner than I did. My "home cage," so to speak, still has the Skinner apparatus in it, but the lever delivers food only occasionally now. I still give it a whirl now and again, but since I'm getting a fairly good supply of food at the end of the maze each time, I don't pay the lever much attention. Now that I am very sure of what is happening to me, quite naturally my thoughts have turned to how I can get out of this situation. Mazes I can solve without too much difficulty, but how to escape apparently is beyond my intellectual capacity. But then, come to think of it, there was precious little chance for my own experimental animals to get out of my clutches. And assuming that I am unable to escape, what then? After He has finished putting me through as many paces as He wishes, where do we go from there? Will He treat me as I treated most of my non-human subjects--that is, will I get tossed into a jar containing chloroform? "Following the experiment, the animals were sacrificed," as we so euphemistically report in the scientific literature. This doesn't appeal to me much, as you can imagine. Or maybe if I seem particularly bright to Him, He may use me for breeding purposes, to establish a colony of His own. Now, that might have possibilities.... Oh, damn Freud anyhow! * * * * * And damn Him too! I had just gotten the maze well learned when He upped and changed things on me. I stumbled about like a bat in the sunlight for quite some time before I finally got to the goal box. I'm afraid my performance was pretty poor. What He did was just to reverse the whole maze so that it was a mirror image of what it used to be. Took me only two trials to discover the solution. Let Him figure that one out if He's so smart! * * * * * My performance on the maze reversal must have pleased Him, because now He's added a new complication. And again I suppose I could have predicted the next step if I had been thinking along the right direction. I woke up a few hours ago to find myself in a totally different room. There was nothing whatsoever in the room, but opposite me were two doors in the wall--one door a pure white, the other jet black. Between me and the doors was a deep pit, filled with water. I didn't like the looks of the situation, for it occured to me right away that He had devised a kind of jumping stand for me. I had to choose which of the doors was open and led to food. The other door would be locked. If I jumped at the wrong door, and found it locked, I'd fall in the water. I needed a bath, that was for sure, but I didn't relish getting it in this fashion. While I stood there watching, I got the shock of my life. I meant it quite literally. The bastard had thought of everything. When I used to run rats on jumping stands, to overcome their reluctance to jump, I used to shock them. He's following exactly the same pattern. The floor in this room is wired but good. I howled and jumped about and showed all the usual anxiety behavior. It took me less than two seconds to come to my senses and make a flying leap at the white door, however. You know something? That water is ice-cold! * * * * * I have now, by my own calculations, solved no fewer than 87 different problems on the jumping stand, and I'm getting sick and tired of it. Once I got angry and just pointed at the correct door--and got shocked for not going ahead and jumping. I shouted bloody murder, cursing Him at the top of my voice, telling Him if He didn't like my performance, He could damn well lump it. All He did, of course, was to increase the shock. Frankly, I don't know how much longer I can put up with this. It's not that the work is difficult. If He were giving me half a chance to show my capabilities, I wouldn't mind it. I suppose I've contemplated a thousand different means of escaping, but none of them is worth mentioning. But if I don't get out of here soon, I shall go stark raving mad! * * * * * For almost an hour after it happened, I sat in this room and just wept. I realize that it is not the style in our culture for a grown man to weep, but there are times when cultural taboos must be forgotten. Again, had I thought much about the sort of experiments He must have had in mind, I most probably could have predicted the next step. Even so, I most likely would have repressed the knowledge. One of the standard problems which any learning psychologist is interested in is this one--will an animal learn something if you fail to reward him for his performance? There are many theorists, such as Hull and Spence, who believe that reward (or "reinforcement," as they call it) is absolutely necessary for learning to occur. This is mere stuff and nonsense, as anyone with a grain of sense knows, but nonetheless the "reinforcement" theory has been dominant in the field for years now. We fought a hard battle with Spence and Hull, and actually had them with their backs to the wall at one point, when suddenly they came up with the concept of "secondary reinforcement." That is, anything associated with a reward takes on the ability to act as a reward itself. For example, the mere sight of food would become a reward in and of itself--almost as much a reward, in fact, as is the eating of the food. The _sight_ of food, indeed! But nonetheless, it saved their theories for the moment. For the past five years now, I have been trying to design an experiment that would show beyond a shadow of a doubt that the _sight_ of a reward was not sufficient for learning to take place. And now look at what has happened to me! I'm sure that He must lean towards Hull and Spence in His theorizing, for earlier today, when I found myself in the jumping stand room, instead of being rewarded with my usual protein balls when I made the correct jump, I--I'm sorry, but it is difficult to write about even now. For when I made the correct jump and the door opened and I started towards the food trough, I found it had been replaced with a photograph. A calendar photograph. You know the one. Her name, I think, is Monroe. I sat on the floor and cried. For five whole years I have been attacking the validity of the secondary reinforcement theory, and now I find myself giving Him evidence that the theory is correct! For I cannot help "learning" which of the doors is the correct one to jump through. I refuse to stand on the apparatus and have the life shocked out of me, and I refuse to pick the wrong door all the time and get an icy bath time after time. It isn't fair! For He will doubtless put it all down to the fact that the mere _sight_ of the photograph is functioning as a reward, and that I am learning the problems merely to be able to see Miss What's-her-name in her bare skin! I can just see Him now, sitting somewhere else in this spaceship, gathering in all the data I am giving Him, plotting all kinds of learning curves, chortling to Himself because I am confirming all of His pet theories. I just wish.... * * * * * Almost an hour has gone by since I wrote the above section. It seems longer than that, but surely it's been only an hour. And I have spent the time deep in thought. For I have discovered a way out of this place, I think. The question is, dare I do it? I was in the midst of writing that paragraph about His sitting and chortling and confirming His theories, when it suddenly struck me that theories are born of the equipment that one uses. This has probably been true throughout the history of all science, but perhaps most true of all in psychology. If Skinner had never invented his blasted box, if the maze and the jumping stand had not been developed, we probably would have entirely different theories of learning today than we now have. For if nothing else, the type of equipment that one uses drastically reduces the type of behavior that one's subjects can show, and one's theories have to account only for the type of behavior that appears in the laboratories. It follows from this also that any two cultures that devise the same sort of experimental procedures will come up with almost identical theories. Keeping all of this in mind, it's not hard for me to believe that He is an iron-clad reinforcement theorist, for He uses all of the various paraphernalia that they use, and uses it in exactly the same way. My means of escape is therefore obvious. He expects from me confirmation of all His pet theories. Well, he won't get it any more! I know all of His theories backwards and forwards, and this means I know how to give Him results that will tear His theories right smack in half! I can almost predict the results. What does any learning theorist do with an animal that won't behave properly, that refuses to give the results that are predicted? One gets rid of the beast, quite naturally. For one wishes to use only healthy, normal animals in one's work, and any animal that gives "unusual" results is removed from the study but quickly. After all, if it doesn't perform as expected, it must be sick, abnormal, or aberrant in one way or another.... There is no guarantee, of course, what method He will employ to dispose of my now annoying presence. Will He "sacrifice" me? Or will He just return me to the "permanent colony"? I cannot say. I know only that I will be free from what is now an intolerable situation. Just wait until He looks at His results from now on! * * * * * FROM: Experimenter-in-Chief, Interstellar Labship PSYCH-145 TO: Director, Bureau of Science Thlan, my friend, this will be an informal missive. I will send the official report along later, but I wanted to give you my subjective impressions first. The work with the newly discovered species is, for the moment, at a standstill. Things went exceedingly well at first. We picked what seemed to be a normal, healthy animal and smattered it into our standard test apparatus. I may have told you that this new species seemed quite identical to our usual laboratory animals, so we included a couple of the "toys" that our home animals seem so fond of--thin pieces of material made from wood-pulp and a tiny stick of graphite. Imagine our surprise, and our pleasure, when this new specimen made exactly the same use of the materials as have all of our home colony specimens. Could it be that there are certain innate behavior patterns to be found throughout the universe in the lower species? Well, I merely pose the question. The answer is of little importance to a Learning Theorist. Your friend Verpk keeps insisting that the use of these "toys" may have some deeper meaning to it, and that perhaps we should investigate further. At his insistence, then, I include with this informal missive the materials used by our first subject. In my opinion, Verpk is guilty of gross anthropomorphism, and I wish to have nothing further to do with the question. However, this behavior did give us hope that our newly discovered colony would yield subjects whose performances would be exactly in accordance with standard theory. And, in truth, this is exactly what seemed to be the case. The animal solved the Bfian Box problem in short order, yielding as beautiful data has I have ever seen. We then shifted it to maze, maze-reversal and jumping stand problems, and the results could not have confirmed our theories better had we rigged the data. However, when we switched the animal to secondary reinforcement problems, it seemed to undergo a strange sort of change. No longer was its performance up to par. In fact, at times it seemed to go quite berserk. For part of the experiment, it would perform superbly. But then, just as it seemed to be solving whatever problem we set it to, its behavior would subtly change into patterns that obviously could not come from a normal specimen. It got worse and worse, until its behavior departed radically from that which our theories predicted. Naturally, we knew then that something had happened to the animal, for our theories are based upon thousands of experiments with similar subjects, and hence our theories must be right. But our theories hold only for normal subjects, and for normal species, so it soon became apparent to us that we had stumbled upon some abnormal type of animal. Upon due consideration, we returned the subject to its home colony. However, we also voted almost unanimously to request from you permission to take steps to destroy the complete colony. It is obviously of little scientific use to us, and stands as a potential danger that we must take adequate steps against. Since all colonies are under your protection, we therefore request permission to destroy it. I must report, by the way, that Verpk's vote was the only one which was cast against this procedure. He has some silly notion that one should study behavior as one finds it. Frankly, I cannot understand why you have seen fit to saddle me with him on this expedition, but perhaps you have your reasons. Verpk's vote notwithstanding, however, the rest of us are of the considered opinion that this whole new colony must be destroyed, and quickly. For it is obviously diseased or some such--as reference to our theories has proven. And should it by some chance come in contact with our other colonies, and infect our other animals with whatever disease or aberration it has, we would never be able to predict their behavior again. I need not carry the argument further, I think. May we have your permission to destroy the colony as soon as possible, then, so that we may search out yet other colonies and test our theories against other healthy animals? For it is only in this fashion that science progresses. Respectfully yours, Iowyy 
48041	----	_BY THE SAME AUTHOR._ =FUN WITH MAGNETISM.= A book and complete outfit for _Sixty-One Experiments_. =FUN WITH ELECTRICITY.= A book and complete outfit for _Sixty Experiments_. =FUN WITH PUZZLES.= A book and complete outfit for _Four Hundred Puzzles_. =FUN WITH SOAP-BUBBLES.= A book and complete outfit for _Fancy Bubbles and Films_. =HUSTLE-BALL.= An American game. Played by means of magic wands and polished balls of steel. =JINGO.= The great war game, including =JINGO JUNIOR=. =HOW TWO BOYS MADE THEIR OWN ELECTRICAL APPARATUS.= A book containing complete directions for making all kinds of simple apparatus for the study of elementary electricity. =THE STUDY OF ELEMENTARY ELECTRICITY AND MAGNETISM BY EXPERIMENT.= This book is designed as a text-book for amateurs, students, and others who wish to take up a systematic course of simple experiments at home or in school. _IN PREPARATION._ =THINGS A BOY SHOULD KNOW ABOUT ELECTRICITY.= This book explains, in simple, straightforward language, many things about electricity; things in which the American boy is intensely interested; things he wants to know; things he should know. _Ask Your Toy Dealer, Stationer, or Bookseller for our Books, Games, Puzzles, Educational Amusements, Etc._ Thomas M. St. John, 407 West 51st St., New York. The Study of Elementary Electricity and Magnetism by Experiment Containing TWO HUNDRED EXPERIMENTS PERFORMED WITH SIMPLE, HOME-MADE APPARATUS BY THOMAS M. ST. JOHN, Met. E. Author of "Fun With Magnetism," "Fun With Electricity," "How Two Boys Made Their Own Electrical Apparatus," Etc. [Illustration: Logo] NEW YORK THOMAS M. ST. JOHN 407 West 51st Street 1900 Copyright, 1900, By THOMAS M. ST. JOHN. To the Student. This book is designed as a text-book for amateurs, students, and others who wish to take up a systematic course of elementary electrical experiments at home or in school. The student is advised to begin at the beginning, to perform the experiments in the order given, and to understand each step before proceeding. Certain principles and explanations necessarily precede the practical and perhaps more interesting applications of those principles. In selecting the apparatus for the experiments in this book, the author has kept constantly in mind the fact that the average student will not buy the expensive pieces usually described in text-books. The two hundred experiments given can be performed with simple, inexpensive apparatus; in fact, the student should make at least a part of his own apparatus. For the benefit of those who wish to make their own apparatus, the author has given, throughout the work, explanations that will aid in the construction of certain pieces especially adapted to these experiments. For those who have the author's "How Two Boys Made Their Own Electrical Apparatus," constant references have been made to it as the "Apparatus Book," as this contains full details for making almost all kinds of simple apparatus needed in "The Study of Elementary Electricity and Magnetism by Experiment." THOMAS M. ST. JOHN. _New York, April, 1900._ The Study of Elementary Electricity and Magnetism by Experiment PART I--MAGNETISM PART II--STATIC ELECTRICITY PART III--CURRENT ELECTRICITY The Study of Elementary Electricity and Magnetism by Experiment. TABLE OF CONTENTS. PART I.--MAGNETISM. PAGE. CHAPTER I. =Iron and Steel= 3 Introduction.--Kinds of iron and steel.--Exp. 1, To study steel.--Discussion.--Exp. 2, To find whether a piece of hard steel can be made softer.--Annealing.--Exp. 3, To find whether a piece of annealed steel can be hardened.--Hardening; Tempering.--Exp. 4, To test the hardening properties of soft iron.--Discussion. CHAPTER II. =Magnets= 7 Kinds of magnets.--Exp. 5, To study the horseshoe magnet.--Poles; Equator.--Exp. 6, To ascertain the nature of substances attracted by a magnet.--Magnetic Bodies; Diamagnetic Bodies.--Practical Uses of Magnets.--Exp. 7, To study the action of magnetism through various substances.--Magnetic Transparency; Magnetic Screens.--Exp. 8, To find whether a magnet can give magnetism to a piece of steel.--Discussion; Bar Magnets.--Exp. 9, To make small magnets.--Exp. 10, To find whether a freely-swinging bar magnet tends to point in any particular direction.--North-seeking Poles; South-seeking Poles; Pointing Power.--The Magnetic Needle; The Compass.--Exp. 11, To study the action of magnets upon each other.--Exp. 12, To study the action of a magnet upon soft iron.--Laws of Attraction and Repulsion.--Exp. 13, To learn how to produce a desired pole at a given end of a piece of steel.--Rule for Poles.--Our Compass.--Review; Magnetic Problems.--Exp. 14, To find whether the poles of a magnet can be reversed.--Discussion; Reversal of Poles.--Exp. 15, To find whether we can make a magnet with two N poles.--Exp. 16, To study the bar magnet with two N poles.--Discussion; Consequent Poles.--Exp. 17, To study consequent poles. Exp. 18, To study the theory of magnetism.--Theory of Magnetism; Magnetic Saturation.--Exp. 19, To find whether soft iron will permanently retain magnetism.--Retentivity or Coercive Force; Residual Magnetism.--Exp. 20, To test the retentivity of soft steel.--Discussion.--Exp. 21, To test the retentivity of hard steel.--Exp. 22, To test the effect of heat upon a magnet.--Discussion.--Exp. 23, To test the effect of breaking a magnet.--Discussion. CHAPTER III. =Induced Magnetism= 20 Exp. 24, To find whether we can magnetize a piece of iron without touching it with a magnet.--Temporary Magnetism; Induced Magnetism.--Exp. 25, To find whether a piece of steel can be permanently magnetized by induction.--Exp. 26, To study the inductive action of a magnet upon a piece of soft iron.--Polarization; Pole Pieces.--Exps. 27-30, To study pole pieces. CHAPTER IV. =The Magnetic Field= 23 Exp. 31, To study the space around the magnet, in which pieces of iron become temporary magnets by induction.--Discussion; The Magnetic Field.--Exp. 32, To study the magnetic field of a bar magnet.--Magnetic Figures; Lines of Magnetic Force.--Exps. 33-37, To study the magnetic fields of various combinations of bar magnets.--Exps. 38-39, To study the lifting power of combinations of bar magnets.--Discussion; Compound Magnets.--Exps. 40-42, To study the magnetic field of the horseshoe magnet.--Discussion; Resistance to Lines of Force.--Exp. 43, To show that lines of force are on all sides of a magnet.--Discussion.--Exp. 44, To study a horseshoe magnet with movable poles.--Discussion; Advantages of Horseshoe Magnets. CHAPTER V. =Terrestrial Magnetism= 31 The Magnetism of the Earth.--Declination.--Exp. 45, To study the lines of force above and below a bar magnet placed horizontally.--The Dip or Inclination of the Magnetic Needle.--Exp. 46, To study the dip or inclination of the magnetic needle due to the action of the earth.--Discussion; Balancing Magnetic Needles.--Exps. 47-48, To study the inductive influence of the earth.--Discussion.--Natural Magnets.--Exp. 49, To test the effect of twisting a wire held north and south in the earth's magnetic field.--Exp. 50, To test for magnetism in bars of iron, tools, etc. PART II.--STATIC ELECTRICITY. CHAPTER VI. =Electrification= 39 Some Varieties of Electricity.--Exp. 51-52, To study electrification by friction.--Discussion.--Electrified and Neutral bodies.--Force; Resistance; Work; Potential Energy; Electrification.--Heat and Electrification.--Exps. 53-54, To study electrical attraction.--Discussion.--Exp. 55, To study mutual attractions.--Mutual Attractions.--Exps. 56-58, To study electrical repulsions.--The Carbon Electroscope.--Discussion of Experiments 56, 57, 58.--Exp. 59, To study the electrification of glass.--Questions.--Exp. 60, To compare the electrification produced by ebonite and flannel with that produced by glass and silk.--Discussion.--Laws. CHAPTER VII. =Insulators and Conductors= 47 Exps. 61-63, To study insulators.--Conductors.--Exp. 64, To study conduction.--Discussion.--Exp. 65, To study conduction.--Telegraph line using static electricity.--Discussion.--Relation between conductors and insulators.--Electrics and Non-electrics.--Exp. 66, To study the effect of moisture upon an insulator.--Discussion.--Exp. 67, To test the effects of moisture upon bodies to be electrified. CHAPTER VIII. =Charging and Discharging Conductors= 52 The Electrophorus.--Exp. 68, To learn how to use the electrophorus.--Exp. 69, To study "charging by conduction."--Exp. 70, To study potential; Electromotive force.--Pressure; Potential; Electromotive force; Current, Spark.--Theories about Electrifications.--Exp. 71, To study some methods of discharging an electrified body.--Disruptive, Conductive and Convective Discharges.--Exp. 72, To study intermittent or step-by-step discharges.--Discussion.--Exp. 73, To ascertain the location of the charge upon an electrified conductor.--Discussion.--Hollow and Solid Conductors.--Exp. 74, To study the effect of points upon a charged conductor.--Electric Density.--Electric Wind. CHAPTER IX. =Induced Electrification= 60 Electric Fields; Lines of Force.--Exp. 75, To study electric induction.--Electric Polarization; Theory of Induction.--Exp. 76, To learn how to charge a body by induction.--Free and Bound Electrifications.--Exp. 77, To show that a neutral body is polarized before it is attracted by a charged one.--Polarization Precedes Attraction.--Exp. 78, To find whether electric induction will act through an insulator.--Dielectrics.--Exp. 79, To find whether a polarized conductor can act inductively upon another conductor.--Successive Induction.--Inductive Capacity.--Exp. 80, To study the action of the electrophorus.--Discussion.--Details of action.--Exp. 81, To see, hear, and feel the results of inductive influence and polarization.--Discussion. CHAPTER X. =Condensation of Electrification= 68 Exp. 82, To find whether a large surface will hold more electrification than a small one.--Electrical Capacity.--Exp. 83, To find whether the capacity of a given conductor can be increased without increasing its size.--Condensation; Condensers.--The Leyden Jar.--Fulminating Panes.--Induction Coil Condensers.--Submarine Cables.--Exp. 84, To study the condensation of electrification.--Discussion.--Exp. 85, To study the action of the condenser.--Discussion.--Exp. 86, To study the effect of electrical discharges upon the human body.--Shocks; Dischargers.--Exps. 87-88, To show the strong attraction between opposite electrifications in the condenser.--Discussion.--Exp. 89, To show how the condenser may be slowly discharged.--The Electric Chime.--Exp. 90, To ascertain the location of a charge in a condenser.--Discussion.--Exp. 91, To find whether any electrification remains in the condenser after it has once been discharged.--Residual Charge.--Exp. 92, To study successive condensation; the chime cascade.--Discussion. CHAPTER XI. =Electroscopes= 77 Electroscopes.--Our leaf electroscope.--Exp. 93, To study the leaf electroscope; charging by conduction.--Discussion.--Exp. 95, To learn some uses of the electroscope.--Discussion.--The Proof-plane. CHAPTER XII. =Miscellaneous Experiments= 81 Exp. 96, To show that friction always produces two kinds of electrification.--Discussion.--Exp. 97, To show "successive sparks."--Exp. 98, To show to the eye the strong attraction between a charged and a neutral body.--Exp. 99, To feel the strong attraction between a charged and a neutral body.--Exp. 100, The human body a frictional electric machine.--Static Electric Machines. CHAPTER XIII. =Atmospheric Electricity= 84 Atmospheric Electricity.--Lightning.--Thunder.--Lightning Rods.--Causes of Atmospheric Electricity.--St. Elmo's Fire.--Aurora Borealis. PART III.--CURRENT ELECTRICITY. CHAPTER XIV. CONSTRUCTION AND USE OF APPARATUS 89 Exp. 101, To study the effect of the electric current upon the magnetic needle.--Electrical Connections.--Current Detectors.--Exp. 102, To study the construction and use of a simple "key."--Exp. 103, To study the construction and use of a simple "current reverser."--Exp. 104, To study the simple current detector.--Exp. 105, To study the construction and use of the simple galvanoscope.--Discussion; True Readings.--Exp. 106, To study the construction and use of a simple astatic needle.--Astatic Needles.--Exp. 107, To study the construction and use of a simple astatic galvanoscope.--Astatic Galvanoscopes. CHAPTER XV. GALVANIC CELLS AND BATTERIES 102 Exp. 108, To study the effect of dilute sulphuric acid upon carbon and various metals.--To amalgamate.--Dilute sulphuric acid.--Discussion.--Exp. 109, To study the effect of dilute sulphuric acid upon various combinations of metals.--Discussion.--Exp. 110, To study the construction of a simple Voltaic or Galvanic cell.--The Electric Current.--Source of the Electrification.--The Electric Circuit; Open and Closed Circuits.--Plates or Elements.--Direction of Current.--Poles or Electrodes.--Chemical Action in the Simple Galvanic Cell.--Action in Cell Using Impure Zinc; Action Using Pure Zinc.--Exp. 111, To see what is meant by "local currents" in the cell.--Local Action; Local Currents.--Reasons for Amalgamating Zinc Plates.--Exp. 112, To study the "single-fluid" Galvanic Cell.--The Simple Cell.--Polarization of Cells.--Effects of Polarization.--Remedies for Polarization; Depolarizers.--Exp. 113, To study the "two-fluid" Galvanic Cell.--Setting Up the Two-Fluid Cell.--Care of Two-Fluid Cell.--Copper Sulphate Solution.--Chemical Action in the Two-Fluid Cell.--Various Galvanic Cells; Open and Closed Circuit Cells.--The Leclanché Cell--Dry Cells.--The Bichromate of Potash Cell.--The Daniell Cell.--The Gravity Cell. CHAPTER XVI. THE ELECTRIC CIRCUIT 115 Exp. 114, To see what is meant by "divided circuits" and "shunts."--Divided Circuits; Shunts.--Exp. 115, To see what is meant by "short circuits." CHAPTER XVII. ELECTROMOTIVE FORCE 117 Electromotive Force.--Unit of E. M. F.; The Volt.--Exp. 116, To see whether the E. M. F. of a cell depends upon the materials used in its construction.--Discussion.--Electromotive Series.--Exp. 117, To see whether the E. M. F. of a cell depends upon its size.--Discussion. CHAPTER XVIII. ELECTRICAL RESISTANCE 120 Resistance.--Exp. 118, To study the general effect of "resistance" upon a current.--External Resistance; Internal Resistance; Unit of Resistance; The Ohm.--Resistance Coils; Resistance Boxes.--Simple Resistance Coil.--Exp. 119, To test the power of various substances to conduct galvanic electricity.--Conductors and Nonconductors.--Exp. 120, To find the effect of sulphuric acid upon the conductivity of water.--Internal Resistance.--Exp. 121, To find what effect the length of a wire has upon its electrical resistance.--Discussion.--Exp. 122, To find what effect the size (area of cross-section) of a wire has upon its electrical resistance.--Discussion.--Exp. 123, To compare the resistance of a divided circuit with the resistance of one of its branches. Discussion.--Exp. 124, To study the effect of decreasing the resistance in one branch of a divided circuit.--Current in Divided Circuits. CHAPTER XIX. MEASUREMENT OF RESISTANCE 130 Exp. 125, To study the construction and use of a simple Wheatstone's Bridge.--The Simple Bridge.--Equipotential Points.--Example.--Exp. 126, To measure the resistance of a wire by means of Wheatstone's Bridge; the "bridge method."--Allowances for Connections.--Exps. 127-137, To measure the resistances of various wires, coils, etc., by the "bridge method."--Table.--Exp. 138, To study the effect of heat upon the resistance of metals.--Effect of Heat upon Resistance.--Exp. 139, To measure the resistance of a wire by the "method of substitution."--Simple Rheostat.--Exp. 140, To measure the E. M. F. of a cell by comparison with the two-fluid cell.--Exp. 141, To measure the internal resistance of a cell by the "method of opposition." CHAPTER XX. CURRENT STRENGTH 142 Strength of Current.--Unit of Current Strength; The Ampere.--Measurement of Current Strength.--The Tangent Galvanometer.--The Ammeter.--The Voltameter.--Unit of Quantity; The Coulomb.--Electrical Horse-power; The Watt.--Ohm's Law.--Internal Resistance and Current Strength.--Exp. 142, Having a cell with large plates, to find how the strength of the current is affected by changes in the position of the plates, the external resistance being small.--Exp. 143, Same as Exp. 142, but with small plates.--Exp. 144, To find whether the changes in current strength, due to changes in internal resistance, are as great when the external resistance is large, as they are when the external resistance is small.--Discussion, with examples.--Arrangement of Cells and Current Strength.--Cells in Series.--Cells Abreast.--Exp. 145, To find the best way to join two similar cells when the external resistance is small.--Exp. 146, To find the best way to join two similar cells when the external resistance is large.--Best Arrangement of Cells. CHAPTER XXI. CHEMICAL EFFECTS OF THE ELECTRIC CURRENT 151 Chemical Action and Electricity.--Electrolysis.--Exp. 147, To study the electrolysis of water.--Composition of Water.--Electromotive Force of Polarization.--Exp. 148, To coat iron with copper.--Exp. 149, To study the electrolysis of a solution of copper sulphate.--Electroplating.--Exp. 150, To study the chemistry of electroplating.--Discussion.--Electrotyping.--Voltameters.--Exp. 151, To study the construction and action of a simple "storage" cell.--Secondary or Storage Cells. CHAPTER XXII. ELECTROMAGNETISM 158 Electromagnetism.--Exp. 152, To study the lines of force about a straight wire carrying a current.--Ampere's Rule.--Lines of Force About Parallel Wires.--Exp. 153, To study the lines of force about a coil of wire like that upon the galvanoscope.--Exp. 154, To study the magnetic field about a small coil of wire.--Coils.--Polarity of Coils.--Exp. 155, To test the attracting and "sucking" power of a magnetized coil or helix.--Exp. 156, To find whether a piece of steel can be permanently magnetized by an electric current.--Exp. 157, To study the effect of a piece of iron placed inside of a magnetized coil of wire. CHAPTER XXIII. ELECTROMAGNETS 165 Electromagnets.--Cores of Electromagnets.--Exps. 158-163, To study straight electromagnets; Lifting power; Residual magnetism of core; Magnetic tick; Magnetic figures; Magnetic field.--Horseshoe Electromagnets.--Use of Yoke.--Experimental Magnets.--Method of Joining Coils.--Exps. 164-173, To study horseshoe electromagnets; To test the poles; To study the inductive action of one core upon the other; Magnetic figures; Permanent Magnetic Figures; Lifting power; Residual magnetism when magnetic circuit is closed.--Closed Magnetic Circuits. CHAPTER XXIV. THERMOELECTRICITY 175 Exp. 174, To find whether electricity can be produced by heat.--Home-made Thermopile.--Thermoelectricity.--Peltier Effect.--Thermopiles. CHAPTER XXV. INDUCED CURRENTS 178 Electromagnetic Induction.--Exp. 175, To find whether a current can be generated with a bar magnet and a hollow coil of wire.--Discussion.--Induced Currents and Work.--Exp. 176, To find whether a current can be generated with a bar magnet and a coil of wire having an iron core.--Exp. 177, To find whether a current can be generated with a horseshoe magnet and a coil of wire having an iron core.--Induced Currents and Lines of Force.--Exp. 178, To find whether a current can be generated with an electromagnet and a hollow coil of wire.--Exp. 179, To find whether a current can be generated with an electromagnet and a coil of wire having an iron core.--Discussion of Exps. 178-179.--Exp. 180, To study the effect of starting or stopping a current near a coil of wire or other closed circuit.--Exp. 181, To study the effect of starting or stopping a current in a coil placed inside of another coil.--Discussion of Exps. 180-181.--Direction of Induced Current.--Laws of Induction.--Primary and Secondary Currents.--Exp. 182, To see what is meant by alternating currents.--Direct and Alternating Currents.--Self-induction; Extra Currents. CHAPTER XXVI. THE PRODUCTION OF MOTION BY CURRENTS 187 Currents and Motion.--Exp. 183, Motion produced with a hollow coil and a piece of iron.--Exp. 184, Motion with hollow coil and bar magnet.--Exp. 185, Motion with electromagnet and piece of iron.--Exp. 186, Motion with electromagnet and bar magnet.--Exp. 187, Motion with electromagnet and horseshoe magnet.--Exp. 188, Motion with two electromagnets.--Discussion of Exps. 183-188.--Exp. 189, Rotary motion with a hollow coil of wire and a permanent magnet.--Exp. 190, Rotary motion with an electromagnet and a permanent magnet.--Discussion of Exps. 189-190. CHAPTER XXVII. APPLICATIONS OF ELECTRICITY 192 Things Electricity Can Do.--Exp. 191, To study the action of a simple telegraph sounder.--Discussion.--Telegraph Line; Connections.--Operation of Line.--Exp. 192, To study the action of the "relay" on telegraph lines.--The Relay.--Exp. 193, To study the action of a two-pole telegraph instrument.--Exp. 194, To study the action of a simple "single needle telegraph instrument."--Exp. 195, To study the action of a simple automatic contact breaker, or current interrupter.--Automatic Current Interrupters.--Exp. 196, To study the action of a simple electric bell, or a "buzzer."--Electric Bells and Buzzers.--Exp. 197, To study the action of a simple telegraph "recorder."--Exp. 198, To study the action of a simple "annunciator."--Discussion.--Exp. 199, To study the shocking effects of the "extra current." Induction Coils.--Action of Induction Coils.--Transformers.--The Dynamo.--The Electric Motor.--Exp. 200, To study the action of the telephone.--The Telephone.--The Bell, or Magneto-transmitter.--The Receiver.--The Carbon Transmitter.--Induction Coils in Telephone Work.--Electric Lighting and Heating.--Arc Lamps.--The Incandescent Lamp. CHAPTER XXVIII. WIRE TABLES 208 APPARATUS LIST 210 INDEX 215 MAGNETISM A Few Dont's for Young Students. Don't fail to make at least a part of your own apparatus; there is a great deal of satisfaction and pleasure in home-made apparatus. Don't experiment in all parts of the house, if working at home. Fit up a small room for your den, and carry the key. Don't begin an experiment before you really know what you are trying to do. Read the directions carefully, then begin. Don't rush through an experiment to see what happens at the end of it. See what happens at each step, and notice every little thing that seems unusual. Don't try to do all parts of an experiment at the same time. Understand one part, then proceed. Don't fail to ask yourself questions, and form an opinion about the results of an experiment before you read what the author has to say about it. Don't fail to keep a note-book. Keep all the data and arithmetical work for future reference. Don't leave the apparatus around after you have finished the day's work. PART I.--MAGNETISM. CHAPTER I. IRON AND STEEL. _=1. Introduction.=_ We should know something about iron and steel at the start, because we are to use them in nearly every experiment. The success with some of the experiments will depend largely upon the quality of the iron and steel used. When we buy a piece of iron from the blacksmith, we get more than iron for our money. Hidden in this iron are other substances (carbon, phosphorus, silicon, etc.), which are called "impurities" by the chemist. If all the impurities were taken out of the iron, however, we should have nothing but a powder left; this the chemist would call "chemically pure iron," but it would be of no value whatever to the blacksmith or mechanic. The impurities in iron and steel are just what are needed to hold the particles of iron together, and to make them valuable. By regulating the amount of carbon, phosphorus, etc., manufacturers can make different grades and qualities of iron or steel. When carbon is united with the _pure_ iron, we get what is commonly called iron. _=2. Kinds of Iron and Steel.=_ _Cast iron_ is the most impure form of iron. Stoves, large kettles, flatirons, etc., are made of cast iron. _Wrought iron_ is the purest form of commercial iron. It usually comes in bars or rods. Blacksmiths hammer these into shapes to use on wagons, machinery, etc. _Steel_ contains more carbon than wrought iron, and less than cast iron. _Soft steel_ is very much like wrought iron in appearance, and it is used like wrought iron. _Hard steel_ has more carbon in it than soft steel. Tools, needles, etc., are made of this. =EXPERIMENT 1. To study steel.= _Apparatus._ A steel sewing-needle (No. 1).[A] [Footnote A: _=NOTE. Each piece of apparatus used in the following experiments has a number. See "Apparatus list" at the back of this book for details. The numbers given under "Apparatus," in each experiment, refer to this list.=_] =3. Directions.= (A) Bend a sewing-needle until it breaks. Is the steel brittle? (B) If you have a file, test the hardness of the needle. _=4. Discussion.=_ "Needle steel" is usually of good quality. It will be very useful in many experiments. Do you know how to make the needle softer? =EXPERIMENT 2. To find whether a piece of hard steel can be made softer.= [Illustration: Fig. 1.] _Apparatus._ Fig. 1. A needle; a cork, Ck (No. 2); lighted candle (No. 3). The bottom of the candle should be warmed and stuck to a pasteboard base. =5. Directions.= (A) Stick the point of the needle into Ck, Fig. 1, then hold the needle in the flame until it is red-hot. (The upper part of the flame is the hottest.) (B) Allow the needle to cool in the air. (C) Test the brittleness of the steel by bending it. Test its hardness with a file (Exp. 1). _=6. Annealing.=_ This process of softening steel by first heating it and then allowing it to cool slowly, is called _annealing_. All pieces of iron and steel are, of course, hard; but you have learned that some pieces are much harder than others. =EXPERIMENT 3. To find whether a piece of annealed steel can be hardened.= _Apparatus._ The needle just annealed and bent; cork, etc., of Exp. 2; a glass of cold water. =7. Directions.= (A) Heat the bent portion of the needle in the candle flame (Exp. 2) until it is red-hot, then immediately plunge the needle into the water. (B) Test its brittleness and hardness, as in Exp. 2. _=8. Hardening; Tempering.=_ Good steel is a very valuable material; the same piece may be made hard or soft at will. By sudden cooling, the steel becomes very hard. This process is called _hardening_, but it makes the steel too brittle for many purposes. By _tempering_ is meant the "letting down" of the steel from the very hard state to any desired degree of hardness. This may be done by suddenly cooling the steel when at the right temperature, it not being hot enough to produce extreme hardness. (The approximate temperature of hot steel can be told by the colors which form on a clean surface. These are due to oxides which form as the steel gradually rises in temperature.) =EXPERIMENT 4. To test the hardening properties of soft iron.= _Apparatus._ A piece of soft iron wire about 3 in. (7.5 cm.) long (No. 4); the candle, water, etc., of Exp. 3. =9. Directions.= (A) Test the wire by bending and filing. (B) Heat the wire in the candle flame as you did the needle (Fig. 1), then cool it suddenly with the water. Study the results. _=10. Discussion.=_ Soft iron contains much less carbon than steel. The hardening quality which steel has is due to the proper amount of carbon in it. If you have performed the experiments so far, you will be much more able to understand later ones, and you will see why we are obliged to use soft iron for some parts of electrical apparatus, and hard steel for other parts. CHAPTER II. MAGNETS. _=11. Kinds of Magnets.=_ Among the varieties of magnets which we shall discuss, are the natural, artificial, temporary, permanent, bar, horseshoe, compound, and electro-magnet. [Illustration: Fig. 2.] _The Horseshoe Magnet_, H M (Fig. 2), is the most popular form of small magnets. The red paint has nothing to do with the magnetism. The piece, A, is called its _armature_, and is made of soft iron, while the magnet itself should be made of the best steel, properly hardened. The armature should always be in place when the magnet is not in use, and care should be taken to thoroughly clean the ends of the magnet before replacing the armature. The horseshoe magnet is _artificial_, and it is called a _permanent_ magnet, because it retains its strength for a long time, if properly cared for. =EXPERIMENT 5. To study the horseshoe magnet.= _Apparatus._ Fig. 2. The horseshoe magnet, H M (No. 16). =12. Directions.= (A) Remove the armature, A, from the magnet, then move A about upon H M to see (1) if the curved part of H M has any attraction for A, and (2) to see if there is any attraction for A at points between the curve and the extreme ends of H M. _=13. Poles; Equator.=_ The ends of a magnet are called its _poles_. The end marked with a line, or an N, should be the _north_ pole. The unmarked end is the _south_ pole. N and S are abbreviations for north and south. The central part, at which there _seems_ to be no magnetism, is called the _neutral point_ or _equator_. =EXPERIMENT 6. To ascertain the nature of substances attracted by a magnet.= _Apparatus._ The horseshoe magnet, H M (Fig. 2); silver, copper, and nickel coins; iron filings (No. 17), nails, tacks, pins, needles; pieces of brass, lead, copper, tin, etc. (Ordinary tin is really sheet iron covered with tin.) Use the various battery plates for the different metals. =14. Directions.= (A) Try the effect of H M upon the above substances, and upon any other substances thought of. _=15. Magnetic Bodies; Diamagnetic Bodies.=_ Substances which are attracted by a magnet are said to be _magnetic_. A piece of soft iron wire is magnetic, although not a magnet. Very strong magnets show that nickel, oxygen, and a few other substances not containing iron, are also magnetic. Some elements are actually repelled by a powerful magnet; these are called _diamagnetic_ bodies. It is thought that all bodies are more or less affected by a magnet. _=16. Practical Uses of Magnets.=_ Many practical uses are made of magnets, such as the automatic picking out of small pieces of iron from grain before it is ground into flour, and the separation of iron from other metals, etc. The most important uses of magnets are in the compass and in connection with the electric current, as in machines like dynamos and motors. (See experiments with electro-magnets.) =EXPERIMENT 7. To study the action of magnetism through various substances.= _Apparatus._ Horseshoe magnet, H M; a sheet of stiff paper; pieces of sheet glass, iron, zinc, copper, lead, thin wood, etc.; sewing-needle. (A tin box may be used for the iron, and battery plates for the other metals.) =17. Directions.= (A) Place the needle upon the paper and move H M about immediately under it. (B) In place of the paper, try wood, glass, etc. (C) Invent an experiment to show that magnetism will act through your hand. (D) Invent an experiment to show that magnetism will act through water. _=18. Magnetic Transparency; Magnetic Screens.=_ Substances, like paper, are said to be _transparent_ to magnetism. Iron does not allow magnetism to pass through it as readily as paper and glass; in fact, thick iron may act as a _magnetic screen_. =EXPERIMENT 8. To find whether a magnet can give magnetism to a piece of steel.= =19. Note.= You have seen that the horseshoe magnet can lift nails, iron filings, etc.; you have used this lifting power to show that the magnet was really a magnet, and not merely an ordinary piece of iron painted red. Can we give some of its magnetism to another piece of steel? Can we pass the magnetism along from one piece of steel to another? _Apparatus._ The horseshoe magnet, H M; two sewing-needles that have never been near a magnet; iron filings. =20. Directions.= (A) Test the needles for magnetism with the iron filings, and be sure that they are not magnetized. (B) Remove the armature, A, from H M, then touch the point of one of the needles to one pole of H M. (C) Lay H M aside, and test the point of the needle for magnetism. (D) If you find that the needle is magnetized, rub its point upon the point of the other needle; then test the point of the second needle for magnetism. _=21. Discussion; Bar Magnets.=_ A piece of good steel will attract iron after merely touching a magnet. To thoroughly magnetize it, however, a mere touch is not sufficient. There are several ways of making magnets, depending upon the size, shape, and strength desired. For these experiments, the student needs only a good horseshoe magnet, or, better still, the electro-magnets described later; with these any number of small magnets may be made. Straight magnets are called _bar magnets_. =EXPERIMENT 9. To make small magnets.= _Apparatus._ Fig. 3. The horseshoe magnet, H M; sewing-needles; iron filings. (See Apparatus Book, Pg. 140, for various kinds of steel suitable for small magnets.) =22. Directions.= (A) Hold H M (Fig. 3) in the left hand, its poles being uppermost. Grasp the point of the needle with the right hand, and place its point upon the N or marked pole of H M. (B) Pull the needle along in the direction of its length (see the arrow), continuing the motion until its head is at least an inch from the pole. (C) Raise the needle at least an inch above H M, lower it to its former position (Fig. 3), and repeat the operation 3 or 4 times. Do not slide the needle back and forth upon the pole, and be careful not to let it accidentally touch the S pole of H M. (D) Test the needle for magnetism with iron filings, and save it for the next experiment. [Illustration: Fig. 3.] [Illustration: Fig. 4.] =EXPERIMENT 10. To find whether a freely-swinging bar magnet tends to point in any particular direction.= _Apparatus._ Fig. 4. A magnetized sewing-needle (Exp. 9); the flat cork, Ck (No. 2); a dish of water. (You can use a tumbler, but a larger dish is better.) =23. Note.= An oily sewing-needle may be floated without the cork by carefully lowering it to the surface of the water. All magnets, pieces of iron and steel, knives, etc., should be removed from the table when trying such experiments. Why? =24. Directions.= (A) Place the little bar magnet (the needle) upon the floating cork, turn it in various positions, and note the result. _=25. North-seeking Poles; South-seeking Poles; Pointing Power.=_ It should be noted that the _point_ swings to the north, provided the needle is magnetized as directed in Exp. 9. This is called the north, or north-seeking pole. The N-seeking pole is sometimes called the marked pole. For convenience, we shall hereafter speak of the N-seeking pole as the N pole, and of the S-seeking pole as the S pole. We shall hereafter speak of the tendency which a bar magnet has to point N and S, as its _pointing power_. An unmagnetized needle has no pointing power. _=26. The Magnetic Needle; The Compass.=_ A small bar magnet, supported upon a pivot, or suspended so that it may freely turn, is called a _magnetic needle_. When balanced upon a pivot having under it a graduated circle marked N, E, S, W, etc., it is called a _compass_. These have been used for centuries. (See Apparatus Book for Home-made Magnetic Needles.) =EXPERIMENT 11. To study the action of magnets upon each other.= _Apparatus._ Two magnetized sewing-needles (magnetized as in Exp. 9); the cork, etc., of Exp. 10. =27. Directions.= (A) Float each little bar magnet (needles) separately to locate the N poles. (B) Leave one magnet upon the cork, and with the hand bring the N pole of the other magnet immediately over the N pole of the floating one. Note the result. (C) Try the effect of two S poles upon each other. (D) What is the result when a N pole of one is brought near a S pole of the other? =EXPERIMENT 12. To study the action of a magnet upon soft iron.= _Apparatus._ A magnetized sewing-needle; cork, etc., of Exp. 10; a piece of soft iron wire, 3 in. long; iron filings. =28. Directions.= (A) Test the wire for magnetism with filings. Be sure that it is not magnetized. If it shows any magnetism, twist it thoroughly before using. (Exp. 19.) (B) Float the magnetized needle (Exp. 10), then bring the end of the wire near one pole of the needle and then near the other pole. (C) Place the wire upon the cork, hold the needle in the hand and experiment. _=29. Laws of Attraction and Repulsion.=_ From experiments 11 and 12 are derived these laws: (_=1=_) _=Like poles repel each other=_; (_=2=_) _=Unlike poles attract each other=_; (_=3=_) _=Either pole attracts and is attracted by unmagnetized iron or steel.=_ The attraction between a magnet and a piece of iron or steel is mutual. Attraction, alone, simply indicates that at least one of the bodies is magnetized; repulsion proves that both are magnetized. =EXPERIMENT 13. To learn how to produce a desired pole at a given end of a piece of steel.= _Apparatus._ Same as in Exp. 9. =30. Directions.= (A) Magnetize a sewing-needle (Exp. 9) by rubbing it upon the N pole of H M from _point to head_. Float it and locate its N pole. (B) Take another needle that has not been magnetized, and rub it on the same pole (N) from _head to point_. Locate its N pole. (C) Magnetize another needle by rubbing it from _point to head_ upon the S pole of H M; locate its N pole. Can you now determine, beforehand, how the poles of the needle magnet will be arranged? _=31. Rule for Poles.=_ The end of a piece of steel which last touches a N pole of a magnet, for example, becomes a S pole. _=32. Our Compass=_ (No. 18). While the floating magnetic needle described in Exp. 10, and shown in Fig. 4, does very well, it will be found more convenient to use a compass whenever poles of pieces of steel are to be tested. Fig. 5 shows merely the cover of the box which serves as a base for the magnetic needle furnished. We shall hereafter speak of this apparatus as _our compass_, O C. (See Apparatus Book, Chap. VII, for various forms of home-made magnetic needles and compasses.) =33. Review; Magnetic Problems.= To be sure that you understand and remember what was learned in Exp. 11, do these problems: 1. Using the S pole of the horseshoe magnet, magnetize a needle so that its head will become a N pole. Test with floating cork, as in Exp. 11. 2. Using the N pole of the horseshoe magnet, magnetize a needle so that its head shall be a S pole. Test. 3. Magnetize two needles, one on the N and one on the S pole of the horseshoe magnet, in such a way that the two points will repel each other. Test. If the student cannot do these little problems at once, and test the results satisfactorily to himself, he should study the previous experiments again before proceeding. [Illustration: Fig. 5.] [Illustration: Fig. 6.] =EXPERIMENT 14. To find whether the poles of a magnet can be reversed.= _Apparatus._ Fig. 6. The horseshoe magnet, H M; a thin wire nail, W N, 2 in. (5 cm.) long; a piece of stiff paper, cut as shown, to hold W N; thread with which to suspend the paper; compass, O C (No. 18). =34. Directions.= (A) Magnetize W N so that its point shall be a S pole. Test with O C to make sure that you are right. (B) Swing W N in the paper (Fig. 6), then _slowly_ bring the S pole of H M near its point. Note result. (C) _Quickly_ bring the S pole of H M near the point. Is W N still repelled? Has its S pole been reversed? _=35. Discussion; Reversal of Poles.=_ The poles of weak magnets may be easily reversed. This often occurs when the apparatus is mixed together. It is always best, before beginning an experiment, to remagnetize the pieces of steel which have already served as magnets. The same may be shown by magnetizing a needle, rubbing it first in one direction, and then in another upon the magnet, testing, in each case, the poles produced. =EXPERIMENT 15. To find whether we can make a magnet with two N poles.= _Apparatus._ The horseshoe magnet, H M; an unmagnetized sewing-needle; compass, O C (No. 18). =36. Note.= You have already learned that the polarity of a weak magnet can be changed (Exp. 14). Can you think of any method by which _two N poles_ can be made in one piece of steel? =37. Directions.= (A) Place the needle upon H M, as in Fig. 7. (B) Keeping the part, C, in contact with the N pole of H M, and using the N pole of H M as a pivot, turn the needle end for end so that its head will be in contact with the S pole of H M. (C) Pull the needle straight from H M, being careful not to slide it in either direction. (D) Test the polarity of the ends with O C (Fig. 5), and save it for the next experiment. [Illustration: Fig. 7.] [Illustration: Fig. 8.] =EXPERIMENT 16. To study the bar magnet with two N poles.= _Apparatus._ The strange magnet just made (Exp. 15); iron filings; compass, O C (No. 18). =38. Directions.= (A) Sprinkle filings over the whole length of the needle and then raise it (Fig. 8). (B) Break the needle at its center, and test, with O C, the two new ends produced at that point. Remember that repulsion is the test for polarity. _=39. Discussion; Consequent Poles.=_ Iron filings cling to a magnet where poles are located. In this case, two small magnets were made in one piece of steel; they had a common S pole at the center. The pointing power (§ 25) of such a magnet is very slight; would it have _any_ pointing power if we could make the end poles of equal strength? Intermediate poles, like those in the needle just discussed, are called _consequent poles_. Practical uses are made of consequent poles in the construction of motors and dynamos. =EXPERIMENT 17. To study consequent poles.= _Apparatus._ An unmagnetized sewing-needle; horseshoe magnet, H M (No. 16); iron filings (No. 17); compass (No. 18). =40. Directions.= (A) Let _w_, _x_, _y_, and _z_ stand for four places along the body of the needle, _w_ being at its point and _z_ at its head. (B) Touch _w_ with the N pole of H M, _x_ with the S pole, _y_ with the N pole, and _z_ with the S pole. Do not slide H M along on the needle, just _touch_ the needle as directed. (C) Cover the needle with filings, then lift it. =EXPERIMENT 18. To study the theory of magnetism.= _Apparatus._ A thin bar magnet, B M (No. 21); iron filings; a sheet of paper. Fig. 9 shows simply the edge of B M and the paper. B M should be magnetized as directed in Exp. 9. [Illustration: Fig. 9.] =41. Directions.= (A) Sprinkle some iron filings upon a sheet of paper. (B) Bring one pole of B M in contact with the filings (Fig. 9), and lightly sweep it through them several times, always in the same direction. Are the filings _simply_ pushed about? (C) Do the same with a stick, and compare the result with that produced with B M. _=42. Theory of Magnetism; Magnetic Saturation.=_ This bringing into line the particles of iron indicates that each particle became a magnet. This experiment should aid in understanding what is thought to take place when steel is magnetized. The pile of filings represents the body to be magnetized, and each little filing stands for a particle of that body. A bar of steel is composed of extremely small particles, called _molecules_. They are very close together and do not move from place to place as easily as the pieces of filings. A magnet, however, when properly rubbed upon the steel, seems to have power to make the molecules point in the same direction. This produces an effect upon the whole bar. Each molecule of the steel is supposed to be a magnet. When these little magnets pull together, the whole bar becomes a strong magnet. When a magnet is jarred, and the little magnetized molecules are mixed again, they pull in all sorts of directions upon each other. This lessens the attraction for outside bodies. Steel is said to be _saturated_, when it contains as much magnetism as possible. A piece of steel becomes slightly longer when magnetized. It is thought, by many, that there is a current of electricity around each molecule, making a little magnet of it. (See electro-magnets.) =EXPERIMENT 19. To find whether soft iron will permanently retain magnetism.= _Apparatus._ A piece of soft iron wire, 3 or 4 in. (7.5 to 10 cm.) long (No. 4); the horseshoe magnet, H M; iron filings; flat cork, F C (No. 2), and the dish of water used in Exp. 10 (Fig. 4). =43. Directions.= (A) Magnetize the wire (Exp. 9). Notice that the wire clings strongly to H M. (B) Test the lifting power of the little wire magnet by seeing about how many iron filings its poles will raise. (C) Test the pointing power (§ 25) of the wire by floating it on F C (Fig. 4). (D) Holding one end of the wire in the hand, thoroughly jar it by striking the other end several times against a hard surface. (E) Test the lifting and pointing powers, as in B and C. _=44. Retentivity or Coercive Force; Residual Magnetism.=_ Soft iron loses _most_ of its magnetism when simply removed beyond the action of a magnet. We say that it does not retain magnetism; that is, it has very little _retentivity or coercive force_. This is an important fact, the action of many electric machines and instruments depending upon it. A slight amount of magnetism remains, however, in the softest iron, after removing it from a magnet. This is called _residual magnetism_. A piece of iron may show poles, when tested with the compass, although it may have almost no pointing power. =EXPERIMENT 20. To test the retentivity of soft steel.= _Apparatus._ A wire nail, W N (No. 19); horseshoe magnet, H M; iron filings; flat cork, F C; the dish of water (Exp. 10, Fig. 4). =45. Directions.= (A) With H M magnetize the nail; this is made of soft steel. (B) Test the lifting and pointing powers of W N (Exp. 19). (C) Strike W N several times with a hammer to jar it. (D) Again test its lifting and pointing powers. _=46. Discussion.=_ Soft steel has a greater retentivity than soft iron. It contains less carbon than cast or tool steel, and is called mild steel or machinery steel. You do not want soft steel for permanent magnets. =EXPERIMENT 21. To test the retentivity of hard steel.= _Apparatus._ A hard steel sewing-needle (No. 1); other articles used in Exp. 20. =47. Directions.= (A) Magnetize the needle with H M. (B) Test its lifting and pointing powers (Exp. 19). (C) Hammer the needle and test again as in (B). =EXPERIMENT 22. To test the effect of heat upon a magnet.= _Apparatus._ A magnetized sewing-needle; the candle, cork, etc., of Exp. 2. (See Fig. 1.) =48. Directions.= (A) Test the needle for magnetism. (B) Stick the needle into the cork (Fig. 1), and heat it until it is red-hot. (C) Test the needle again for magnetism. (D) See if you can again magnetize the needle. _=49. Discussion.=_ Heating a body is supposed to thoroughly stir up its molecules. Jarring or twisting a magnet tends to weaken it. (See Exp. 19.) The molecules of steel do not move about or change their relative positions as readily as those of soft iron. When the molecules of hard steel are once arranged, by magnetizing them, for example, they strongly resist any outside influences which tend to mix them up again. A magnet does not attract a piece of red-hot iron. The particles of the hot iron are supposed to vibrate too rapidly to be brought into line; that is, the iron cannot become polarized by induction. (See Exp. 24.) =EXPERIMENT 23. To test the effect of breaking a magnet.= _Apparatus._ A magnetized sewing-needle; iron filings; compass, O C (No. 18). [Illustration: Fig. 10.] =50. Directions.= (A) Break the little bar magnet (needle), and test the two new ends produced for magnetism, with the iron filings. (Fig. 10). (B) Touch the two new poles together to see whether they are like or unlike. (C) Test the nature of the poles with O C (Fig. 5) (D) Break one of the halves and test its parts. _=51. Discussion.=_ The above results agree with the theory that each molecule is a magnet (Exp. 18). No matter into how many pieces a magnet is broken, each part becomes a magnet. (Fig. 10). This shows that those molecules near the equator of the magnet really have magnetism. Their energy, however, is all used upon the adjoining molecules; hence no external bodies are attracted at that point. CHAPTER III. INDUCED MAGNETISM. [Illustration: Fig. 11.] =EXPERIMENT 24. To find whether we can magnetize a piece of iron without touching it with a magnet.= _Apparatus._ Horseshoe magnet, H M; iron filings, I F (Fig. 11). =52. Directions.= (A) Hold the armature of the magnet in a vertical position (Fig. 11), its lower end being directly in a little pile of iron filings. (B) Bring the N pole of H M near the upper end of A, but do not let them touch each other. (C) Keeping A and the pole of H M the same distance apart, lift them. Do any filings cling to A? (D) Without moving or jarring A, take H M away from it and note result upon the filings. _=53. Temporary Magnetism; Induced Magnetism.=_ The armature, A, was induced to become a magnet without even touching H M. Its magnetism was _temporary_, however, as the filings dropped as soon as the _inductive action_ of H M was removed. A small amount of residual magnetism (44) remained in A. Soft iron is exceedingly valuable, because it has very little retentivity (44), and because it can be easily _magnetized by induction_. The armature was made of soft iron. It had _induced magnetism_. It was a _temporary magnet_. =EXPERIMENT 25. To find whether a piece of steel can be permanently magnetized by induction.= _Apparatus._ An unmagnetized sewing-needle; horseshoe magnet, H M; iron filings; sheet of stiff paper. =54. Directions.= (A) Test the needle for magnetism. (B) Place the unmagnetized needle upon the paper, then move H M about immediately under it, so that the needle will be attracted. (C) Test the needle again for permanent magnetism. [Illustration: Fig. 12.] =EXPERIMENT 26. To study the inductive action of a magnet upon a piece of soft iron.= _Apparatus._ Horseshoe magnet, H M; iron filings, I F; a piece of soft iron wire about an inch long, I W (Fig. 12), placed upon the N pole of H M; compass, O C (No. 18), (§ 32). =55 Directions.= (A) Test the lower end of I W for magnetism with I F. (B) Leaving I W upon the N pole of H M, test the pole at the lower end of I W with O C, to determine whether it is N or S. (C) Jar I W (Exp. 19), then place it upon the S pole of H M, and again test the polarity of the lower end. _=56. Polarization; Pole Pieces.=_ The wire, I W (Fig. 12), was acted upon by induction (Exp. 24) and behaved like a magnet. Poles were produced in it, so we say that the wire was _polarized_. Pieces of iron, placed upon the poles of a magnet, are called _pole pieces_. It should be noted that the lower end of the wire has a pole _like_ the pole of H M, to which it is attached. =EXPERIMENTS 27-30. To study pole pieces.= _Apparatus for Experiments 27-30._ Horseshoe magnet, H M; soft iron wires; iron filings, I F. =57. Directions.= (A) Suspend two wires, each about an inch long (Fig. 13) from one pole of H M. Do their lower ends attract or repel each other? [Illustration: Fig. 13.] [Illustration: Fig. 14.] =EXPERIMENT 28.= =58. Directions.= (A) Place the two wires just used so that one shall cling to the N pole of H M, and the other to the S pole of H M (Fig. 14). (B) Bring the lower ends of the wires near each other. Do they attract or repel each other? =EXPERIMENT 29.= =59. Directions.= (A) Bend a 2-inch iron wire, as in Fig. 15, and place it upon the poles of H M. (B) See if its central part, marked X, will strongly attract filings. [Illustration: Fig. 15.] [Illustration: Fig. 16.] =EXPERIMENT 30.= =60. Directions.= (A) Bend the wire just used a little more, and place its ends upon _one_ pole of H M (Fig. 16). (B) See if the iron filings and small wires will cling to its central part. CHAPTER IV. THE MAGNETIC FIELD. =EXPERIMENT 31. To study the space around a magnet, in which pieces of iron become temporary magnets by induction.= _Apparatus._ A bar magnet, B M (No. 21); a compass (No. 18); a sheet of stiff paper about 1 ft. (30 cm.) square, with a center line, C L, drawn parallel to one of its sides (Fig. 16-1/2), and with another line, E W, drawn perpendicular to C L. (See Apparatus Book, Chap. VI., for various ways of making home-made permanent magnets.) =61. Directions.= (A) Lay the paper upon the table, and place the compass over the center of the line, C L, previously drawn. (B) Place the eye directly over the compass-needle, then turn the paper until the line is N and S; that is, until the line is parallel to the length of the needle. Pin the paper to the table to hold its center line N and S. (C) Place B M upon the paper, as shown (Fig. 16-1/2), its N pole to the north, and its center at the cross line, E W. [Illustration: Fig. 16-1/2.] (D) Slowly move the compass entirely around and near B M, and note the various positions taken by the needle. Note especially the way in which its N pole points. This is to get a general idea of the action of the needle. (E) Place the compass in the position marked 1, which is on E W, about 1 in. from the line, C L. Press the wooden support down firmly upon the paper to show, by the dent made in the paper by the pin-head, the exact place on the paper that is under the center of the compass-needle. Before removing the compass from this position, look down upon it again, and make a dot on the paper with a pencil directly under each end of the needle. Remove the compass, and draw a line through the dent and the two dots just made. This will show a plan of the exact position of the needle. (F) Repeat this for the various points marked 2, 4, 6 in. from C L, always marking on the plan the position of the N pole of the needle. Do the same with the other points marked on Fig. 16-1/2 by dots, and study the resulting diagram. _=62. Discussion; The Magnetic Field.=_ The compass-needle was decidedly affected all around B M (Fig. 17), showing that induction can take place in a considerable space around a magnet; this space is called the _magnetic field_ of the magnet. Let us consider _one_ position taken by the compass-needle in the field of B M (Fig. 17), as, for example, the one in which the needle has been made black. The S pole of the black needle is attracted by the N pole of B M, and is repelled by the S pole of B M. The N pole of the compass-needle is attracted by the S pole of B M, and is repelled by B M's N pole. The position which it takes, therefore, is due to the action of these 4 forces, together with its tendency to point N and S. [Illustration: Fig. 17.] Every magnet has a certain magnetic field, with its lines of force passing through the surrounding air in certain definite positions. As soon, however, as a piece of iron or another magnet is brought within the field, the original position of the lines of force is changed. This has to be considered in the construction of electrical machinery. =EXPERIMENT 32. To study the magnetic field of a bar magnet.= _Apparatus._ A sheet of stiff paper; iron filings, I F; bar magnet, B M (No. 21); a sifter for the filings (No. 24); (See Apparatus Book, §48, 49, 50, for home-made sifters.) =63. Directions.= (A) Place B M upon the table, and lay the paper over it. (B) With the sifter sprinkle some filings upon the paper directly over B M, then tap the paper gently, to assist the particles to take final positions. Study the results. _=64. Magnetic Figures; Lines of Magnetic Force.=_ The filings clearly indicated the extent and nature of the magnetic field of B M. You should notice how the filings radiate from the poles, and how they form curves from one pole to the other. They make upon the paper a _magnetic figure_. Each particle of the filings becomes a little magnet, by induction (Exp. 24), and takes a position which depends upon attractions and repulsions, as discussed in Exp. 31. Magnetism seems to reach out in lines from the poles of a magnet. The position and direction of some of the lines are shown by the lines of filings. They are very distinct near the poles, and are considered, for convenience, to start from the N pole of a magnet, where they separate. They then pass through the air on all sides of the magnet, and finally enter it again at the S pole. These lines are called _lines of force_ or _lines of magnetic induction_. The poles must not be considered mere points at the ends of a magnet. As shown by magnetic figures, the lines of magnetic induction flow from a considerable portion of the magnet's ends. =EXPERIMENTS 33-37. To study the magnetic fields of various combinations of bar magnets.= _Apparatus for Exps. 33-37._ Two bar magnets, B M (Nos. 21, 22); an iron ring, I R (No. 23); iron filings, I F; a sheet of stiff paper; the sifter (No. 24). =65. Note.= The student will find it very helpful to make the magnetic figures of the combinations given. Thoroughly magnetize the bar magnets upon an electro-magnet, or upon a strong horseshoe magnet, and mark their N poles in some way. The N poles may be marked by sticking a small piece of paper to them. =66. Directions.= (A) Arrange the two magnets, B M, as in Fig. 18, with their unlike poles about an inch apart. (The dotted circle indicates the iron ring to be used in the _next_ experiment. About a quarter, only, of the magnets are shown.) (B) Place the paper over the magnets, and sift filings upon it immediately over the unlike poles. Note particularly the lines of filings between N and S. (C) Make a sketch of the result. (See experiments with electromagnets, and the illustrations of magnetic figures with them.) =EXPERIMENT 34.= =67. Directions.= (A) Leaving the opposite poles an inch apart, as in Exp. 33, place the iron ring, I R (No. 23), between them (Fig. 18, dotted circles). (B) Place the paper over it all, and sprinkle filings upon it to get the magnetic figure. (C) Make a sketch of the resulting figure, and compare it with the figure made in Exp. 33. Why do the lines of force appear indistinct in the center of the ring and around it? (See §74.) [Illustration: Fig. 18.] [Illustration: Fig. 19.] =EXPERIMENT 35.= =68. Directions.= (A) Arrange the two bar magnets, as in Exp. 33, but with their two N poles an inch apart. (B) Make the magnetic figure of the combination. Do the lines of force flow from one N pole directly to the N pole of the other? Do the particles of filings reaching out from one B M attract or repel those from the other B M? =EXPERIMENT 36.= =69. Directions.= (A) Place the two bar magnets side by side, so that their unlike poles shall be arranged as in Fig. 19. (B) Make the magnetic figure. =EXPERIMENT 37.= =70. Directions.= (A) Turn one B M end for end, so that their like poles shall be near each other, but otherwise arranged as in Fig. 19. (B) Make and study the magnetic figure. =EXPERIMENTS 38-39. To study the lifting power of combinations of bar magnets.= _Apparatus for Exps. 38-39._ Two bar magnets, B M (No. 21, 22), of about equal strength; iron filings, I F. =71. Directions.= (A) Find out about how many filings you can lift with the N pole of one magnet. (B) Place the two magnets together (Fig. 20), their _like_ poles being in contact; then see whether the two N poles will lift more or less filings than one pole. [Illustration: Fig. 20.] =EXPERIMENT 39.= =72. Directions.= (A) Remove all filings from the two magnets just used, and hold them tightly together (Fig. 20), with their _unlike_ poles in contact. (B) Compare the amount of filings you can lift at one end of this combination with that lifted in Exp. 38 (A) and (B). _=73. Discussion; Compound Magnets.=_ Many lines of force pass into the air from two like poles. Such a combination is called a _compound magnet_. A piece of thin steel can be magnetized more strongly in proportion to its weight than a thick piece, because the magnetism does not seem to penetrate beyond a certain distance into the steel. Thin steel may be magnetized practically through and through. A thick magnet has but a crust of magnetized molecules; in fact, a thick magnet may be greatly weakened by eating the outside crust away with acid. By riveting several thin bar or horseshoe magnets together, thick permanent magnets of considerable strength are made. _=74.=_ Lines of force, in passing from the N to the S pole of a magnet, meet a resistance in the air, which does not carry or conduct them as easily as iron or steel. In the arrangement of Exp. 39 the lines of force are not obliged to push their way through the air, as each magnet serves as a return conductor for the lines of force of the other. Either magnet may be considered an armature for the other. To show in another way that few lines of force pass into the air, the student may lay the above combination upon the table and make a magnetic figure. (See Apparatus Book, p. 38, for method of making home-made compound magnets.) In the case where a ring was placed between the poles of two bar magnets (Exp. 34), the lines of force from the N pole jumped across the first air-space. They then disappeared in the body of the ring, until they were obliged to jump across the second air-space, to get to the S pole. The weakness of the field in the central space was clearly shown by the filings. There were no stray lines of force passing through the air, because it was easier for them to go through the iron ring. This will be discussed again under "Dynamos and Motors." (See also § 78.) =EXPERIMENTS 40-42. To study the magnetic field of the horseshoe magnet.= _Apparatus for Exps. 40-42._ Horseshoe magnet, H M; iron filings, I F; sheet of stiff paper. =75. Directions.= (A) Place H M, with its armature removed, flat upon the table, and cover it with the paper; then make the magnetic figure. (Exp. 32.) (B) Compare the number of well-defined curves at the poles with the number at the equator. =EXPERIMENT 41.= =76. Directions.= (A) Make the magnetic figure of H M with its armature in place. (B) Is the attraction for outside bodies increased or decreased by placing the armature on H M? =EXPERIMENT 42.= =77. Directions.= (A) Lay H M flat upon the table, and place one or two matches between its poles and the armature; cover with paper as before, and make the magnetic figure. Do lines of force still pass through the armature? _=78. Discussion; Resistance to lines of Force.=_ It is evident, from the last 3 experiments, that lines of force will pass through iron whenever possible, on their way from the N to the S pole of a magnet. When the armature of a horseshoe magnet is in place, most of the lines of magnetic induction crowd together and pass through it rather than push their way through the air. Air is not a good conductor of lines of force; and the magnet has to do work to overcome the resistance of the air, when the armature is removed, in order to complete the magnetic circuit. This work causes a magnet to become gradually weaker. The soft iron armature is an excellent conductor of lines of force; it completes the magnetic circuit so perfectly that very little work is left for the magnet to do. =EXPERIMENT 43. To show that lines of force are on all sides of a magnet.= _Apparatus._ Our compass, O C (No. 18); horseshoe magnet, H M; glass tumbler, G T; sheet of stiff paper; iron filings, I F. Arrange as in Fig. 21. H M may be supported in a vertical position by placing paper, or a handkerchief, under it. The poles should just touch the stiff paper placed over the tumbler. [Illustration: Fig. 21.] =79. Directions.= (A) Sprinkle iron filings upon the paper, and study the resulting magnetic figure. (B) Place O C upon the paper in different positions. Does the magnetic needle always come to rest about parallel to the lines of filings? _=80. Discussion.=_ The student should keep in mind the fact that the filings in the magnetic figure show the approximate extent and form of the magnetic field simply in one plane. If the paper were held in some other position near the magnet (in a tilted position, for example,) the lines of filings would not be the same as those produced in Exp. 40-42. The lines of force come out of every side of the N pole. When a magnetic needle is placed in any magnetic field, its N pole points in the direction in which the lines of force are passing; that is, it points towards the S pole of the magnet producing the field. =EXPERIMENT 44. To study a horseshoe magnet with movable poles.= _Apparatus._ A narrow strip of spring steel, S S (No. 25); iron filings, I F. =81. Directions.= (A) Magnetize the spring steel, S S. (B) Bend S S until its poles are about 1/4 in. apart, then using it as a horseshoe magnet, and keeping its poles the same distance apart, see about how many filings you can lift. (C) Clean the poles of S S, press them tightly together, then again test its lifting power with filings. [Illustration: Fig. 22.] _=82. Discussion; Advantages of Horseshoe Magnets.=_ When the opposite poles of the flexible magnet are pressed together, the lines of force do not have to pass through the air; there is very little attraction for outside bodies. The same effect is produced with the armature (Exp. 41). A horseshoe magnet has a strong attraction for its armature, because it has a _double power to induce and to attract_. Suppose the N pole of a bar magnet, B M (Fig. 22), be placed near one end of a piece of iron, as, for example, the armature, A. A will become a temporary magnet by induction (Exp. 24). The S pole of A, polarized by induction, will be attracted by B M, while its N pole will be repelled by B M; so, you see, that a bar magnet does not pull to advantage. CHAPTER V. TERRESTRIAL MAGNETISM. _=83. The Magnetism of the Earth.=_ The student must have guessed, before this, that the earth acts like a magnet. It causes the magnetic needle to take a certain position at every place upon its surface, and this position depends upon the earth's attractions and repulsions for it. The earth has lines of force which flow from its N magnetic pole, and these lines, before they can get to the earth's S magnetic pole, must spread out through the air on all sides of the earth. As the magnetic needle points to the earth's N magnetic pole (which is more than 1,000 miles from its _real_ N pole), it is evident that the compass-needle does not show the _true_ north for all places upon the earth's surface. In fact, the N pole of the needle may point E, W, or even S. This effect would be seen by carrying a compass around the earth's N magnetic pole. [Illustration: Fig. 23.] _=84. Declination.=_ For convenience, we shall represent the true N and S, at the place where you are experimenting, by the full line, N S, in Fig. 23. The dotted line shows the direction taken by the compass-needle. The angle, A, between them, is called the _angle of variation_ or the _declination_. This angle is not the same for all places; and, in fact, it changes slowly at any given place; so it becomes necessary to construct _magnetic maps_ for the use of mariners and others. =EXPERIMENT 45. To study the lines of force above and below a bar magnet placed horizontally.= _Apparatus._ A bar magnet, B M (No. 21); compass, O C (No. 18). =85. Directions.= (A) Lay B M upon the table and place O C upon its center. Note the position of the compass-needle. (B) Slide O C along from one end of B M to the other, and study the effect upon its needle. Do lines of force curve _over_ B M as well as around its sides, as shown in Exp. 31? (C) Place O C upon the table. Hold B M horizontally above O C, and move O C back and forth under B M. Does the needle remain horizontal, or does it show that lines of force pass _under_ B M on their way from its N to its S pole? [Illustration: Fig. 24.] _=86. The Dip or Inclination of the Magnetic Needle.=_ The needle is said to dip when it takes positions like those in Fig. 24. Compass-needles should be horizontal, when properly balanced, and entirely free from all effects other than those of the earth. The excessive dip shown (Fig. 24) is due, of course, to the efforts of the magnetic needle to place itself in the direction in which the lines of force of B M pass. =EXPERIMENT 46. To study the dip or inclination of the magnetic needle, due to the action of the earth.= _Apparatus._ Fig. 25. Our compass, O C (No. 18); horseshoe magnet, H M (No. 16); piece of paper. =87. Directions.= (A) Place O C upon the table, and mark upon a piece of paper the height of the N pole of its needle above the table. (Fig. 25.) The paper should be held in a vertical position, and near the pole. [Illustration: Fig. 25.] (B) With H M reverse the poles of the compass-needle (Exp. 13), so that its former N pole shall become a S pole. (C) Place the needle upon its pivot again, and mark upon the paper, as before, the height of its new N pole above the table. Does the needle remain horizontal? (D) Remagnetize the needle, and reverse its poles so that it will again balance. [Illustration: Fig. 26.] _=88. Discussion; Balancing Magnetic Needles.=_ If a piece of unmagnetized steel be balanced and then magnetized, it will no longer remain horizontal; it will dip. Try this. Compass-needles are balanced after they are magnetized. Can you now see why the needle did not remain horizontal after its poles were changed? A piece of steel first balanced and then magnetized, has to have its S pole slightly weighted, as suggested by the line at S (Fig. 26 x), to make it horizontal. The magnetic needle does not tend to dip at the earth's equator, because the lines of force of the earth are nearly horizontal at the equator. As we pass toward the north or south on the earth, the lines of force slant more and more as they come from or enter the earth's magnetic poles. What position would the needle take if we should hold it directly over the earth's N magnetic pole? Fig. 24 shows what the needle does when held near the poles of a bar magnet. =EXPERIMENTS 47-48. To study the inductive influence of the earth.= _Apparatus for Exps. 47-48._ Compass, O C, (No. 18); an iron stove poker, or other rod of iron; a hammer. (The iron and hammer are not furnished.) =89. Note.= You have seen (Exp. 24), that iron becomes magnetized by induction when placed near a magnet. As the earth acts like a huge magnet, having poles, lines of force, etc., will it magnetize pieces of iron which are in the air or upon its surface? =90. Directions.= (A) Test the poker for poles with O C, remembering that _repulsion_ is necessary to prove that it is polarized. If the poker has very weak poles, proceed; but if it shows some strength, hold it in an east and west direction, and hit it several sharp blows on the end with the hammer. Test for polarity again. (B) With one hand hold the poker in the N and S line, give it a dip toward the north, and strike it several times with the hammer to thoroughly stir up its molecules. (C) Test again for poles with O C, and note especially whether the lower end (of the poker) became a N or a S pole. =EXPERIMENT 48.= =91. Directions.= (A) Turn the poker end for end (See Exp. 47); repeat the striking, and test again the pole produced at the lower and north end of it. (B) Now hold the poker horizontally in the east and west line, and pound it. (C) Test for poles. Has this strengthened or weakened the poker magnet? _=92. Discussion.=_ Dipping the poker places it nearly in the same direction as that taken by the earth's lines of force. The magnetic influence of the earth acts to advantage upon the poker, by induction, only when the poker is properly held. It no doubt occurs to the student that the end of a magnetic needle which points to the north is really opposite in nature to the north magnetic pole of the earth. The N pole of a needle, then, must be in reality a S pole to be attracted by the earth's N pole. It has been agreed, for convenience, to call the N-seeking pole of a magnet its N pole. _=93. Natural Magnets.=_ Nearly all pieces of iron become more or less magnetized by the inductive action of the earth's magnetism. Your poker was slightly magnetized at the start, perhaps, from standing in a dipping position. Induction takes place along lines of force. In northern latitudes the earth's lines of force have a dip to the north. You should now see why the greatest effect was produced upon the poker when it, also, was made to dip. Parts of machinery, steel frames of bridges and buildings, tools in the shop, and even certain iron ores, become polarized by this inductive action. These might all be called natural magnets. Magnetic iron ore, called lodestone, is referred to, however, when speaking of _natural magnets_. Lodestone was used thousands of years ago to indicate N and S, and it was discovered, later, that it could impart its power to pieces of steel when the two were rubbed together. =EXPERIMENT 49. To test the effect of twisting a wire held north and south in the earth's magnetic field.= _Apparatus._ Compass, O C (No. 18); a piece of soft iron wire, 6 in. (15 cm.) long (No. 15). Bend up about an inch of the wire at each end so that it may be firmly held when twisting it. =Note.= You have seen that we can _pound_ magnetism into or out of a piece of iron at will. Can we _twist_ it into a wire and out again without the use of magnets? =94. Directions.= (A) Test the wire for poles with O C. (B) Hold the wire in a N and S direction, dipping it at the same time, as directed in Exp. 47 for the poker, and twist it back and forth. (C) Test again for poles with O C. As the poles of the wire may be very weak, bring them _slowly_ toward the compass-needle (see Exp. 14), and note the _first_ motions produced upon the needle. (D) Hold the wire horizontally east and west, twist and test again. Has its magnetism become weaker or stronger than before? =EXPERIMENT 50. To test for magnetism in bars of iron, tools, etc.= _Apparatus._ Steel drills; files; chisels; bars or rods of iron that have been standing in an upright position; stove-lid lifters; stove pokers, etc., etc.; a compass. =95. Directions.= (A) With the compass test the ends of the above for magnetism, and note which ends are S. Notes. STATIC ELECTRICITY PART II.--STATIC ELECTRICITY CHAPTER VI. ELECTRIFICATION. _=100. Some Varieties of Electricity.=_ _Static electricity_ does not seem to "flow in currents" as readily as some other varieties; its tendency is to stand still, hence the name, static. The simplest way to produce it is by friction. _Thermo electricity_ is produced by changes in temperature. When certain combinations of metals become hotter or colder, a current is produced. _Voltaic_ or _Galvanic electricity_ is produced by chemical action. Batteries give this variety. _Induced electricity_ is produced by other currents, and by combinations of magnets and moving coils of wire, as in the dynamo. This is, by far, the most important variety of electricity, and the dynamo is the most important producer of it. Each of the above varieties of electricity will be studied experimentally with simple apparatus. =EXPERIMENTS 51-52.= To study electrification by friction. _Apparatus._ Ebonite sheet, E S (No. 26); flannel cloth, F C (No. 30). See what is said in preface about static electricity. =101. Directions.= (A) Examine E S. Note that its surface is not smooth, like that of ordinary hard-rubber combs. Can you think of any reason for this? (B) Hold its flat surface near your face, then near the back of your hand. Do you feel anything unusual? (C) Lay E S upon a flat board, or uncovered wooden table, and slide it about. Can you easily pick it up? (D) Place E S flat upon the table again; keep it from sliding about with your left hand, and rub it _vigorously_ for a _minute_ with F C. Does E S act exactly as it did before in (B) and (C)? (E) Repeat the experiment in a dark room. (F) Thoroughly electrify E S, and see if it will cling to the wall strongly enough to support its own weight. _=102. Discussion; Electrified and Neutral Bodies.=_ The ebonite sheet became _electrified_ or _charged_; and as the _electrification_ was produced by friction, we may say that the action of the ebonite indicated the presence of _frictional electricity_. No one can tell _just_ why the ebonite acted so queerly, but we can learn a great deal by experimenting. Bodies which are not charged are said to be _neutral_. The table, chairs, earth, etc., are neutral. We may consider that a neutral body has been _discharged_. _=103. Force; Resistance; Work; Potential Energy; Electrification.=_ It takes _force_ to raise water into a tank placed on the roof. In raising the water, _work_ has to be done, and _we_ have to do the work; but when we once have the water in the tank we have accomplished something. The water has _potential energy_; that is, on account of its high _position_, we can make it do some work by simply turning a stop-cock so that the water can run out and turn a water-wheel, for example. It takes _force_ to vigorously rub a piece of ebonite with a flannel cloth, for _resistance_ has to be _overcome_; that is, _work_ has to be done. Several things are accomplished by this work; heat is produced, for we can _feel_ that the ebonite gets warm; we can _hear_ sounds and _see_ sparks. The simple muscular exertion on our part has been changed to heat, light, and sound. The most wonderful part of it all, however, is that we have electrified or charged the ebonite. _We_ did the work at first, and now the ebonite has the power to do something, as you will soon see. _Electrification_ is, then, a sort of potential energy. _=104. Heat and Electrification.=_ We say that heat passes to or from a body to make it hot or cold. Heat _produces_ the sensation of warmth, but heat isn't warmth. We can force a cold body to become hot; in other words, we can get it into a hot condition in various ways, such as rubbing it, hammering it, or by placing it near or in contact with another hot body. Electrification is, also, a condition or state into which we can force a body; but electrification isn't electricity. We know whether a body is hot or cold by its effects upon us, upon thermometers, and upon other bodies. We can tell, also, whether a body is electrified or not by the way it acts, and, in certain cases, by the sound, heat, and light which accompany the electrification. Do not get the idea that an electrified body is covered with a layer of electricity just as a board is covered with a layer of paint. [Illustration: Fig. 28.] =EXPERIMENT 52.= =105. Directions.= Repeat Exp. 51, but in place of the ebonite, use hot tissue-paper, hot brown paper, hot newspaper, or a hot silk handkerchief. Rub your hand vigorously over them. Do these become charged? =EXPERIMENTS 53-54. To study electrical attractions.= _Apparatus._ The ebonite sheet, E S (No. 26); flannel cloth, F C (No. 30); small pieces of dry tissue-paper, T P (No. 31); thread (No. 32). =106. Directions.= (A) Thoroughly electrify E S as before, then lift and hold it in the air. (Fig. 28.) (B) See what the paper and thread will do when held loosely near E S. _=107. Discussion.=_ Exp. 53 shows that _an electrified body attracts neutral ones_. This much was known about electricity over 2,000 years ago. They didn't have ebonite then, but some of the educated men of Greece knew that amber would attract light bodies after being rubbed. The Greek word for amber is _elektron_, and from this has been made the word _electricity_. =EXPERIMENT 54.= =108. Directions.= Charge a sheet of hot paper by friction; lift it, by its opposite ends, and lower it over small pieces of tissue-paper placed on the table. What happens to the little pieces? =EXPERIMENT 55. To study mutual attractions.= _Apparatus._ The support and its attachments (See § 109); support wire, S W (No. 36); silk thread, S T (No. 33), or a rubber band, R B (No. 45); ebonite rod, E R (No. 28); flannel cloth, F C (No. 30); wire swing, W S (No. 37). Tie one end of S T to W S, Fig. 29; tie the other end of S T to S W; adjust W S by bending, if necessary, so that it will securely hold E R. It will be found convenient to use a rubber band instead of S T; if you do, let W S straddle one end of R B (Fig. 33), and hang the other end of R B upon S W. =109. The support= consists of a support base (S B, Fig. 56), a support rod (S R, Fig. 56), and a support wire (S W, Fig. 29). There is a small hole in one end of S R to receive the wire, S W, and a large hole in the other end to take the short ebonite which holds the insulating table (Fig. 32). A little paper should be wound around the lower end of S R, so that it will stand solidly in the spool which forms a part of the base. =110. Directions.= (A) Electrify E R with F C, and place E R in the swing, W S (Fig. 29). [Illustration: Fig. 29.] (B) Bring your finger near one side of the rubbed end of E R, then near the unrubbed end, and compare the results. =111. Mutual Attractions.= _A neutral body_, like the hand, for example, _attracts electrified ones_. From Exp. 53, 54, 55, it is seen that the attraction between a neutral and an electrified body is mutual; each attracts the other. =EXPERIMENT 56. To study electrical repulsions.= _Apparatus._ Same as for Exp. 55; ebonite sheet, E S (No. 26). =112. Directions.= (A) Charge E R, and place it in W S, Fig. 29. (B) Charge E S, and bring it slowly near one side of the charged end of E R. =EXPERIMENT 57. To study electrical repulsions.= _Apparatus._ A sheet of tissue-paper, T P (No. 31); shears or a knife. Cut T P, as in Fig. 30. Each leg should be about 1/4 in. wide and 3 or 4 in. long. =113. Directions.= (A) Heat the paper, then place it flat upon the table and electrify it by rubbing it with your hand. You must rub away from the uncut part, or you will break the legs. (B) Raise T P, holding it by the uncut part. Note the action of legs, and make a sketch of them. [Illustration: Fig. 30.] [Illustration: Fig. 31.] =EXPERIMENT 58. To study electrical repulsions.= _Apparatus._ Ebonite rod, E R (No. 28); a carbon electroscope, C E, Fig. 31 (see § 114); the support complete (see § 109); small piece of damp tissue-paper. _=114. The Carbon Electroscope.=_ Light an ordinary match, and let it burn until it is charred through and through. The black substance remaining is _carbon_. This is very light; it has, also, another important property which you will soon understand. Tie a small piece of the carbon to one end of a dry _silk_ thread, and fasten the other end of the thread to the support wire, S W, which is fastened to the support (Fig. 31). We shall call this piece of apparatus the _carbon e-lec-tro-scope_. (See Electroscopes, Chapter XVIII., Apparatus Book.) =115. Directions.= (A) Electrify E R, then hold it near the carbon of the electroscope. (B) Bring the charged rod near little pieces of _damp_ tissue-paper. _=116. Discussion of Experiments 56, 57, 58.=_ In 56 the two pieces of ebonite were made of the same material, and both were rubbed with flannel. They must have been similarly electrified. In 57, different parts of the same piece of paper were similarly electrified. In 58, the little piece of carbon took some of the electrification from the charged rod, just as it would take molasses from your finger should your sticky finger touch it. The electrification on the carbon must have been of the same kind as that on the rod. The carbon was _charged by contact_. We learn, then, that _two bodies repel each other when they have the same kind of electrification_. Do two charged bodies _always_ repel each other? Is it possible that there are different kinds of electrifications? =EXPERIMENT 59. To study the electrification of glass.= _Apparatus._ The sheet of glass, G (No. 38), heated (a hot bottle or lamp chimney will do); a piece of silk large enough to rub G. (A silk handkerchief is just the thing, but in case you have no silk, use the flannel cloth, F C, No. 30.) =117. Directions.= (A) Vigorously rub the hot glass with the silk (or flannel), also heated. (B) Test G for electrification by means of little pieces of tissue-paper and the carbon electroscope, Exp. 58. _=118. Questions.=_ Will two pieces of electrified glass repel each other? Arrange an experiment to show whether you are right or not. Is the charge on the glass exactly like that on the ebonite? Do you know how to find out? =EXPERIMENT 60. To compare the electrification produced by ebonite and flannel with that produced by glass and silk.= _Apparatus._ The support (see § 109); wire swing, W S (No. 37); ebonite rod, etc., of Exp. 55 (Fig. 29); the glass, G, and silk of Exp. 59. =119. Directions.= (A) Electrify E R, and place it in W S, Fig. 29. (B) Bring the uncharged glass near E R, noting the action of E R. (C) Heat and electrify G; bring it near E R, and carefully note whether the attraction between them is stronger or weaker than before, or whether they repel each other. _=120. Discussion.=_ We know that the glass was electrified, because it lifted tissue-paper; hence, its charge was not of the same kind as that on the ebonite. Had the electrifications been exactly alike, we should have had a repulsion (Exps. 56, 57, 58). The exact difference between these two kinds of electrifications is not known. It has been agreed, for convenience, to call that produced by glass and silk a _positive_ electrification. With ebonite and flannel a _negative_ electrification is produced. The sign + is generally written for the word positive, and - for negative. These signs indicate _kind_, and not more or less, as in arithmetic. _=121. Laws.=_ We have learned from the experiments these facts, which are called _laws_: (1) Charges of the same kind repel each other; (2) charges of unlike kinds attract each other; (3) either kind of a charge attracts, and is attracted by a neutral body. CHAPTER VII. INSULATORS AND CONDUCTORS. =EXPERIMENT 61. To study insulators.= _Apparatus._ Ebonite rod, E R (No. 28); flannel cloth, F C (No. 30); tissue-paper, T P (No. 31). =122. Directions.= (A) Holding one end of E R in the hand, charge the other end by rubbing it with F C. (B) With bits of the T P test each end of E R for a charge, and compare the results. =EXPERIMENT 62. To study insulators.= _Apparatus._ The ebonite sheet, E S (No. 26); flannel cloth, F C (No. 30). =123. Directions.= (A) Thoroughly electrify E S (Exp. 51, D), then lift and hold it in the air, as in Fig. 28. (B) By moving your rounded knuckle about near the surface of E S, see if you can get more than one spark from it. =EXPERIMENT 63. To study insulators.= _Apparatus._ A hard-rubber comb (not furnished); flannel cloth, F C (No. 30); dull pointed nail (No. 19). =124. Directions.= (A) Electrify the comb with F C. (B) Move the nail along near the teeth of the comb, and listen carefully. _=125. Discussion of Experiments 61, 62, 63; Insulators.=_ In 61 the electrification remained at one end of the rod. In 62 and 63 the sparks showed that all parts of the ebonite were not discharged at the same time. A substance, like ebonite, which will not allow electrification to pass from one part of it to another, is called an _insulator_. Silk and glass are also insulators. Do you now see why a silk thread was used to make the carbon electroscope? Why do they fasten telegraph wires to glass insulators? _=126. Conductors.=_ It has already been stated that water in an elevated tank has potential energy. We can allow the water to flow through a conducting pipe to another tank a little lower than the first, and it will still retain much of the potential energy, but not all. Can we conduct from one place to another this peculiar state of things, this queer form of potential energy which we call electrification? It is clear, from the last experiments, that in order to do it we need something besides ebonite, which really acts like a closed stop-cock to the flow of electrification. To keep electrification in one place we need an insulator; to get it from one place to another we need a _conductor_. Insulators are as important as conductors. You saw that sparks went to the finger from the ebonite, so we call the finger a conductor. You have learned that attractions and repulsions show the presence of electrification. Can we have our charged body in one place and get attractions or repulsions at some other place? [Illustration: Fig. 32.] =EXPERIMENT 64. To study conduction.= _Apparatus._ Fig. 32; the support (see § 109); a bent hairpin, H P (No. 39); ebonite sheet, E S; flannel cloth, F C; tin disk, B F B (No. 40), which is the bottom of the flat-box, F B; the insulating table, I T (see § 127). =127. The Insulating Table= consists of a tin box (exactly like that used for the electrophorus cover), and an ebonite rod about 1-3/4 in. long. See § 139 for full details about fitting the rod into the box, etc. The lower end of the short rod fits into the large hole in one end of the support rod, S R. Arrange as in Fig. 32. B F B should swing about very easily. =128. Directions.= (A) Charge E S, then rub it upon I T, as shown, noting the action of B F B. _=129. Discussion.=_ Ebonite being an insulator (§ 125), we say that I T, H P and B F B were _insulated_. You can see that the electrification must have passed through I T and H P to get to the disk, B F B. H P was the _conductor_, allowing the disk, also, to become charged. The wood, S R, is a conductor, and, as it was not insulated from the earth, S R was neutral. Account for the attraction. (See § 121.) [Illustration: Fig. 33.] =EXPERIMENT 65. To study conduction.= _Apparatus._ A copper wire, C W (No. 44); insulating rubber band, R B (No. 45, Fig. 33); wire swing, W S (No. 37); the other half of the flat box, T F B (No. 41); apparatus of Exp. 69. =130. Telegraph Line.= To have our telegraph line using frictional electricity complete, we must have: (1) Some way of generating or making the electricity; (2) Some means of getting it or its effects to the other end of the line; (3) Some way of showing that it has been taken there. The charged E S will be the source of the electrification. New York will represent the end at which we _send_ the message, so at N. Y. we must have a _sending instrument_. See Fig. 33, which explains itself. R B or a silk thread must be used to _insulate_ the sender. Around one leg of W S is twisted one bare end of the _conductor_, C W. Boston will represent the end of the line at which the message is received, and there we need a _receiving instrument_. This is similar to the apparatus described in Exp. 69, Fig. 37. In addition to this, tie the middle of a moist cotton thread that is 6 in. long, to B C (Fig. 37), and let its two free ends lie over the top and reach down against the bottom of the tin; that is, on the left-hand side. Fig. 42 will give you an idea in regard to the looks of the thread; at first, however, it should be close to the bottom of the tin. Twist the other bare end of the copper wire around B C. When the line is properly constructed and ready for use, both instruments and C W are entirely insulated. Do not let any part of C W touch the table or your clothing. =131. Directions.= (A) Touch the insulated sending instrument with the charged ebonite sheet, and watch for any motion in the receiving instrument. =Note.= Better results will be obtained by using the charged electrophorus cover as the source of electrification, instead of E S. (Exp. 68.) _=132. Discussion.=_ The action here was like that in the previous experiment, the difference being that a longer _conductor_ was used. Electrification is always looking for some place to get to the earth, just as water will run from a roof to the ground. You will understand more about it a little later. In our apparatus just described, the only way that the earth could be reached was through the wooden rod S R. Do not get the idea that real messages are sent in any such way, or that electricity flows through a wire as water flows through a pipe. _=133. Relation between Conductors and Insulators.=_ The above terms are merely relative. Static electricity is easily conducted by dry wood, while Galvanic electricity is practically insulated by it. A substance may be an insulator for currents of low potential, while at the same time it will conduct high potential currents. (See Potential § 144.) _=134. Electrics and Non-electrics.=_ Bodies like glass, sealing-wax, amber, etc., were called electrics by the first students of electricity, because it was upon these substances that they could easily produce electrification. They called iron and other metals non-electrics, because they could detect no electrification after rubbing them. Can you explain why they did not detect any electrification on metals? Can you devise an experiment to prove that metals may be charged? Do you see any relation between a non-electric and a conductor? =EXPERIMENT 66. To study the effect of moisture upon an insulator.= _Apparatus._ Same as for Exp. 65, with the exception of the copper wire; this is to be replaced by a dry silk thread about 2 feet (60 cm.) long (No. 33). =135. Directions.= (A) See if a charge can be sent through the thread, in the same manner as it was through the copper. Is dry silk a conductor? (B) Thoroughly wet the thread, being careful not to wet the rubber band insulator (Fig. 33); see if wet silk is a conductor. _=136. Discussion.=_ Dry silk is an insulator, while wet silk is a good conductor of _static_ electricity. It is the water, however, which really does the conducting. Even small amounts of moisture on glass, or other insulators, will allow the charge to escape. Glass collects much moisture from the air. Do you now see why it is necessary, to get good results, to have the paper, glass, etc., hot before electrifying them? =EXPERIMENT 67. To test the effects of moisture upon bodies to be electrified.= _Apparatus._ Two pieces of newspaper, each about 4 in. (10 cm.) square. =137. Directions.= (A) Heat one piece to make it thoroughly dry, and leave the other cold. (B) Stroke each, say 10 times, with your hand, pressing them upon the table; then place them upon the wall at the same time, being careful not to let them touch your clothing. See which will cling to the wall the longer. CHAPTER VIII. CHARGING AND DISCHARGING CONDUCTORS. _=138. The Electrophorus.=_ While the ebonite sheet alone, or a good hard-rubber comb, may be used for many experiments in frictional electricity, the sparks produced are small, and the ebonite has to be electrified as often as it is discharged. To obtain real good sparks, and to avoid this continual rubbing, the student should be provided with an _e-lec-troph'-o-rus_. This is, really, a simple, cheap, and efficient frictional electric machine. An electrophorus consists of 2 insulators and 1 conductor--that is, of 3 parts: (1) insulating handle, (2) cover, and (3) a plate or base of insulating material. [Illustration: Fig. 34.] =139. Our Electrophorus= is shown in Fig. 34. For the insulating _handle_ use the ebonite rod, E R (No. 28); for the _plate_, use the ebonite sheet, E S (No. 26). The _electrophorus cover_, E C (No. 42), furnished, is a tin box with a fancy top. A hole has been punched in the center of its top, and into the hole has been riveted a short tube, so that the handle, E R, can be firmly held. The hole has been made a little larger than E R for convenience. To make E R fit tightly in the hole, so that you can lift E C, wrap a small piece of paper around the end of E R before pushing it into the hole. You can easily find out how much paper to use to make a good fit. With a knife cut away all loose points of paper that stick out of the hole around E R; this is _important_. The top and bottom of E C should be pressed firmly together. First learn how to use the electrophorus. With the large amount of electrification produced we can then find out how it works. =EXPERIMENT 68. To learn how to use the electrophorus.= _Apparatus._ Shown in Figs. 34, 35. _Do not fail to read_ § 139. =140. Directions.= (A) Place E S upon a _flat_, uncovered, wooden table, and rub it _vigorously_ for a _minute_ with the _warm_ flannel, F C, to thoroughly charge it. Do not let E S slide about, and do not lift it from the table. (B) With the right hand grasp E R at its extreme end, and place E C upon E S. (C) Touch E C for an instant with a finger of your left hand (Fig. 35). (D) Remove your finger entirely from E C, then lift E C by its insulating handle, E R, at the same time holding E S down to the table, if it tries to follow E C. [Illustration: Fig. 35.] [Illustration: Fig. 36.] (E) Bring your left hand near E C (Fig. 36). You should get a good spark from E C. (F) It is not necessary to immediately rub E S again. You have discharged E C by taking a spark from it. To _recharge_ it, simply place it upon E S again; let it remain there while you count 5; touch it as before, and then lift by E R. =141. Extra Notes.= You may repeat the above operation many times. As soon as the sparks begin to get small, electrify E S again. The charge on E C is +, although that on E S is -. You will understand, later, why this is so. =If you do not get a good spark= from the electrophorus, read the directions again. The ebonite must be well electrified; the cover must be lifted by the _end_ of its handle; you must _touch_ the cover and _withdraw your finger_ from it _before_ lifting. You must allow the cover to remain upon the ebonite 3 or 4 seconds each time. The board, or table, upon which E S rests, must be _flat_, and not warped, so that E C will fit down perfectly upon E S. =EXPERIMENT 69. To study "charging by conduction."= _Apparatus._ Fig. 37. To one end of a _silk_ thread, S T, is tied a little bent clamp, B C (No. 46); the other end of S T is tied to the support wire, S W (No. 36); the bottom of the flat box, B F B (No. 40), is supported by B C, and thus _insulated_ from the table and earth; the electrophorus (Exp. 68) is also necessary. =142. Directions.= (A) Charge E C (Exp. 68), and bring it near B F B (Fig. 37). Note the spark. (B) Repeat (A) twice, noting the relative sizes of the sparks. Does B F B continue to be attracted by E C? (C) Bring your knuckle slowly towards the charged disk, B F B. [Illustration: Fig. 37.] [Illustration: Fig. 38.] =EXPERIMENT 70. To study potential; electro-motive force.= _Apparatus._ The insulating table, I T, Fig. 38. (For details see Exp. 64; the electrophorus Exp. 68). =143. Directions.= (A) Pass a spark from the thoroughly charged E C (Exp. 68) to I T. (B) Recharge E C, and see how many times I T will take good sparks from it, and note the relative sizes of the sparks. (C) As soon as I T refuses to take more sparks from E C, touch E C to see if it is completely discharged. (D) Touch I T. _=144. Pressure; Potential; Electro-motive Force.=_ Water runs down hill. It always tries to run from a high place to a lower one. Electrification acts very much like water in this respect. We say that water has a _pressure_, or a _head_ of so many feet. In speaking of a charge, we say that it has a _potential, or an electro-motive force_. Water may have a high or low pressure, and a charge may have a high or low potential. The greater the pressure of water, the harder it tries to break away and get somewhere; the greater the potential of a charge, the farther it will jump to your hand. _=144a. Current; Spark.=_ Electrification will easily pass from a place of high potential to one of low potential through a conductor, and when it _passes_ we say we have an _electric current_, or a _current of electricity_. Water has no desire to flow on a dead level, and the electric current does not care to flow between two places of equal potential. The potential of the earth and of all neutral bodies is zero; that is, they have no charge, no potential; so it is very easy for a charge to escape into the earth. Dry air is a pretty good insulator, but when the attraction between a charged and a neutral body gets great enough, the spark rips right through the air. Benjamin Franklin proved by experiment that lightning is caused by the electrification in the clouds and air. (See Atmospheric Electricity.) =145. Theories about Electrifications.= _The "One-Fluid" Theory_ suggests that neutral bodies have a certain amount of electrification, and that they have a certain potential called zero potential. If the potential of a body becomes greater than that of the earth, the body is said to be positively electrified; if the potential of the body is less than that of the earth, it is said to be negatively electrified. If we fill a bottle with sea water, we have a great deal of water when we compare it with the bottle, but a very little water when we compare it with the sea. The earth is so large that small amounts of electrification taken from it or added to it do not affect its potential to any extent. =146.= _The "Two-Fluid" Theory_ suggests that there are two absolutely different kinds of electrification, one called positive (+), and the other negative (-). When these two are equal in quantity, the body is said to be neutral. If the body contains more + than -, the body is said to be charged positively. It is evident then, if the two-fluid theory be accepted, that no matter how strongly a body is charged positively there must be in it _some_ negative electrification; that is, we may charge a neutral body + by adding + electrification to it, or by taking - electrification from it. There must always be, then, some + and - electrifications in a body. These theories do not require much consideration by the student of elementary electricity. The best thing he can do is to learn what electricity can do, and how it can be used. [Illustration: Fig. 39.] =EXPERIMENT 71. To study some methods of discharging an electrified body.= _Apparatus._ The electrophorus (Exp. 68); an ordinary pin (Fig. 39). =147. Note.= You have seen sparks pass from E C to your rounded knuckle, and to other conductors. In all of these cases the discharge was _sudden_, one spark doing the work. Can we _slowly_ discharge E C, or discharge it without sounds? =148. Directions.= (A) Thoroughly charge E C, and test it with your knuckle to be sure that it is working properly. (B) Charge E C again; hold the pin in your left hand (Fig. 39), and _slowly_ bring its _head_ toward E C; listen for sparks. (C) Recharge E C, and bring the _point_ of the pin slowly toward it. Touch E C to see whether it has been discharged or not. _=149. Disruptive, Conductive, and Convective Discharges.=_ Sudden discharges, accompanied by bright sparks, are said to be _disruptive_. When the electrification is continuously carried away by a conductor, there is a _conductive_ discharge. There is a _convective_ discharge when the electrification escapes from points into the air. (See § 155.) The nature of the discharge depends upon the potential of the charge, upon the nature of the charged conductor, and upon the nature of the surrounding air and objects. Convective discharges are often _silent_, as in Exp. 71 (C). In this case, electrification passed from the earth through the pin-point to the cover to neutralize it. (See Induced Electricity.) [Illustration: Fig. 40.] =EXPERIMENT 72. To study intermittent or step-by-step discharges.= _Apparatus._ Electrophorus (Exp. 68); carbon electroscope (§ 114), (Exp. 58). =150. Directions.= (A) Charge E C, then hold your hand on one side of the carbon (Fig. 40), and hold E C upon the opposite side. What should the carbon do? _=151. Discussion.=_ The carbon and E C were insulated, while the hand was "grounded"--that is, it was connected with the earth. Carbon is a good conductor; it may be quickly charged and discharged. =EXPERIMENT 73. To ascertain the location of the charge upon an electrified conductor.= _Apparatus._ The electrophorus (Exp. 68); the insulating table, I T (Exp. 64); the tin box, T B (No. 47), Fig. 41; a piece of moist cotton thread, C T, 5 or 6 in. long, bent double, and hung over the edge of the open box, T B. One-half of C T should be inside of T B, which, in turn, should stand on I T. [Illustration: Fig. 41.] =152. Directions.= (A) Charge E C; pass a spark to T B, and note the action of both parts of C T. _=153. Hollow and Solid Conductors.=_ The moist thread, being a conductor, became charged as well as the box. The electrification seemed to be entirely on the outside of T B. A hollow conductor will hold as large a charge as a solid one having the same amount of surface. This refers to charges of static electricity, not to currents. An electric current passes through the whole substance of a conductor. =EXPERIMENT 74. To study the effect of points upon a charged conductor.= _Apparatus._ The electrophorus (Fig. 34); a pin, bent slightly to keep it from rolling. =154. Directions.= (A) Charge E C; test its charge with your knuckle. Be sure that you get a good spark. (B) Charge E C again, and hold it by its insulating handle, E R, long enough to count 10 before discharging it with your knuckle. Be sure that it holds its charge during this time. (C) While E C is upon E S (Fig. 34), lay the bent pin upon E C, so that its point will project into the air. The point should stick out about 1/4 in. from the edge of E C. (D) Touch E C; raise it by E R; count 10 as before; then test with your knuckle to see if E C is still charged. _=155. Electric Density; Electric Wind.=_ A charge resides upon the outside of a conductor (Exp. 73), and it continually tries to escape. It seems to pile up at points and corners, and we say that it is denser at such places than at well-rounded parts of a charged conductor. All points and sharp places should be removed from a conductor, if it is desired to keep a charge for any length of time. Electrification may escape from a point so rapidly that currents are produced in the surrounding air. As the particles of air become charged, they repel each other. The movement of the air particles may be so great that a lighted candle will be affected when placed near the point. This current of air is called _electric wind_. Electrification easily passes from points, and the electrophorus may be easily and silently discharged by holding a pointed pin near it (Exp. 71, C). Thorns, leaves with sharp edges, etc., have a great effect upon atmospheric electricity. They allow a silent escape of electrification from the earth to neutralize that in the clouds which is opposite in nature. (See Atmospheric Electricity.) CHAPTER IX. INDUCED ELECTRIFICATION. _=156. Electric Field; Lines of Force.=_ In our study of magnetism you learned that a magnet can act through the air, and induce a piece of iron to become a magnet. You saw how the iron filings arranged themselves around the magnet, showing that the lines of force reached out from the poles in a very peculiar manner. There is an _electric field_ all around a charged conductor, just as there is a magnetic field about a magnet. The lines of force in the electric field pass from the positively charged body to the negatively charged one, or to some neutral one, which, you will soon see, is practically the same thing. When the positively charged electrophorus cover is held above the negatively charged ebonite sheet, a very strong electric field exists between them. =157. Note.= You have seen that we can _charge_ an insulated conductor by _touching_ it with the charged cover, or by allowing a spark to pass to the conductor. What effect, if any, has a charged body upon an insulated conductor _before_ they touch each other, and before any spark passes to the conductor? [Illustration: Fig. 42.] =EXPERIMENT 75. To study electric induction.= _Apparatus._ Fig. 42. The insulating table, I T (for details see Exp. 64); tin box, T B (No. 47, Fig. 42); moist cotton thread, C T; the electrophorus (Exp. 68); tie C T around one end of the closed T B, and leave the ends of C T long enough to hang down over the end. Place a match on each side of T B to keep it from rolling. =158. Directions.= _Part 1._--(A) Pass a spark from the charged E C to T B, and note the action of the thread, which will be our electroscope. Remove E C. (B) Touch the charged T B with the finger, watching C T. _Part 2._ (C) Bring the re-charged E C near the neutral T B, and parallel to its end surface; but keep them at least an inch apart, so that a spark cannot pass. Watch C T. (D) Withdraw E C, and try to explain the action of C T. _=159. Electric Polarization; Theory of Induction.=_ This experiment should remind the student of Exp. 24, in magnetism, in which a piece of soft iron was magnetized by the inductive action of a magnet. The soft iron was in a magnetic field; it became polarized. Is it possible that the box, T B, was polarized, being in the electric field of E C? We know, by the action of C T (Fig. 42), that the top end of T B was charged while E C was in place. The charge was not conducted. You know, from previous experiments, that + and - electrifications rush together whenever possible. Why can we not suppose that a neutral body, like the box at the start, contains an equal amount of both kinds, and that these different electrifications have already rushed together? If you imagine a small army of positive soldiers struggling, "man to man," with the same number of equally strong negative soldiers, you can readily see that one-half of them can hold the other half from running away. A body remains neutral, then, according to this idea, as long as it has an equal quantity of the two opposite kinds of electrification. (See Theories, § 145, 146.) As soon as the positively charged E C was brought near T B, it destroyed the neutrality of T B, by pulling at its - electrification, and by pushing back its + electrification to the top end and into C T. We say that the charged E C produced a separation of the combined electrifications of T B by _induction_, and not by contact. As soon as the inductive action of E C was removed, T B became neutral again. [Illustration: Figs. 43-44.] =160. Note.= Figs. 43 and 44 may aid the student. In Fig. 43, T B is supposed to be neutral. The "double sign" means that the + and - electrifications are united; and, as there are an equal number of both kinds, none are left free to tell the tale. Fig. 44 shows what happens when the + E C is near. What would happen if we could cut into T B at the middle with an insulated knife while it is polarized by E C? =EXPERIMENT 76. To learn how to charge a body by induction.= _Apparatus._ Fig. 42, same as in Exp. 75. =161. Directions.= (A) Bring the charged E C within an inch of the bottom of T B, and as soon as C T is repelled, showing that T B is polarized (Exp. 75), touch T B with your finger; then remove your finger while you still hold E C in place. (B) Withdraw E C and its inductive action. Explain the motions of C T during the experiment. Is it still repelled by T B after E C is removed? _=162. Free and Bound Electrifications.=_ As explained in Exp. 75, and as shown in Fig. 44, T B became polarized. The - electrification was drawn towards E C; it was held or _bound_ there as long as E C was near. The + was actually repelled by E C, and it was _free_ to escape through your arm as soon as T B was touched, leaving the top end of T B neutral. As soon as E C was removed, the - electrification, no longer held by E C, spread all over T B and on to C T. T B was _charged by induction_. It was charged negatively by driving out + electrification. =EXPERIMENT 77. To show that a neutral body is polarized before it is attracted by a charged one.= _Apparatus._ The electrophorus (Exp. 68); dry tissue-paper, T P. Cut out 2 pieces of T P, each about 1/4 inch square. =163. Directions.= (A) Place the bits of dry T P upon a board or table, and convince yourself that they are attracted equally by the charged E C. (B) Slightly moisten one piece of T P only. See if one is attracted by E C more readily than the other. _=164. Polarization Precedes Attraction.=_ Dry tissue-paper is not a good conductor; you have seen (Exp. 52) that it can be electrified, which indicates that it is at least a partial insulator. Insulators are not easily polarized. (Why?) Even if the pieces of T P were polarized, the opposite electrifications were so near each other that the attraction of E C for the - was nearly overcome by the repulsion for the +; the result being that T P was not strongly attracted by E C until the + had a chance to escape. The moist tissue-paper allowed its + to escape more quickly than the dry piece. A conductor is attracted by a charged body more strongly than an insulator, because the latter is not easily polarized. A neutral body, then, is really no longer neutral when it is in the electric field. _Polarization precedes attraction._ =EXPERIMENT 78. To find whether electric induction will act through an insulator.= _Apparatus._ Small bits of carbon (Exp. 58); bits of moist tissue-paper, T P; one-half of the flat box, T F B (No. 41); sheet of glass, G (No. 38); electrophorus (Exp. 68). Place the carbon and T P into T F B (Fig. 45), and cover with the glass. =165. Directions.= (A) Charge the electrophorus cover, E C (Exp. 68), move it about a little above the glass, and see if the carbon, etc., are attracted. _=166. Dielectrics.=_ The carbon must have been polarized and attracted _through_ the glass. You saw, Exp. 7, that the lines of magnetic force could penetrate and act through paper, glass, etc.; it is now evident that the electric field is not easily fenced in, even by an insulator. Substances, like the glass, which allow this inductive influence to act through them, are called _dielectrics_. [Illustration: Fig. 45.] [Illustration: Fig. 46.] =EXPERIMENT 79. To find whether a polarized conductor can act inductively upon another conductor.= _Apparatus._ Fig. 46. Insulating table, I T (for details see Exp. 64); ebonite sheet, E S (No. 27); flat box complete F B (Nos. 40, 41); sheet of glass, G (No. 38); small piece of slightly moist tissue-paper, T P; charged electrophorus cover, E C. Arrange as shown. =167. Directions.= (A) Hold E C, charged, near and under I T, then bring your finger, F, near T P. Explain the action of T P. _=168. Successive Induction.=_ The inductive influence of E C first polarized I T; this acted through the dielectric, E S, and polarized F B, which, in turn, polarized T P through the second dielectric, G. This induction after induction is called _successive induction_. _=169. Inductive Capacity.=_ Dielectrics are insulators. Two substances may be equally good insulators, that is, they may equally well resist the _spread_ of electrification _over_ their surfaces, or the _flow_ of the electric current _through_ them, while one may be, nevertheless, a better _dielectric_ than the other. The better the dielectric, the easier it is for the electric field to polarize a conductor placed beyond the dielectric. A good dielectric is said to have a high _inductive power or capacity_. Glass is about 3 times as good a dielectric as dry air; and as the latter (under certain conditions) is taken as the standard, or as unity, we may say that the _specific inductive capacity_ of glass is about 3. =EXPERIMENT 80. To study the action of the electrophorus.= _Apparatus._ The electrophorus (Exp. 68); small bits of moist tissue-paper, T P. =170. Directions.= (A) Thoroughly electrify E S, Fig. 34, and place E C upon it by its handle, E R. (B) Touch E C, as directed in Exp. 68, and listen for a small spark which should pass from E C to your finger. (C) Again, place a little piece of T P upon E C before lowering it upon E S. Do not touch E C, but bring your finger near T P. What does T P do? Now, touch E C and see, when you bring your finger near it, if T P acts as it did before. (D) Again, place several pieces of T P upon E C (E S being thoroughly charged); touch E C, then lift it by its handle. Note action of T P, which should be slightly moist. _=171. Discussion.=_ The electrification upon the ebonite is negative (Exp. 60). Although E S and E C (Fig. 34) seem quite smooth, there are many little hills, valleys, and air-spaces between them, which keep them from touching each other perfectly. The ebonite has the electric field at the start, and it really acts across these minute air-spaces _by induction_ (Exp. 75), and polarizes E C. The air-spaces form the dielectric (Exp. 78). The - electrification of E C being repelled by the - of E S, it is driven to the top of E C, while the + is drawn to the bottom. This + is kept from rushing to the - of E S by the air dielectric, and because E S is a non-conductor. By touching E C the free - escapes to the earth, leaving E C _positively_ charged when it is lifted. [Illustration: Fig. 47.] [Illustration: Fig. 48.] [Illustration: Fig. 49.] [Illustration: Fig. 50.] [Illustration: Fig. 51.] =172. Details of Action.= The different steps in the action of the electrophorus are shown graphically in Figs. 47 to 51. Fig. 47 shows E S negatively charged. E C is neutral at first, Fig. 48; that is, it is supposed to contain both + and -, as shown by the "double sign" (§ 160). Fig. 49 shows that E C has been polarized by the inductive action of E S. The repelled - escapes to the finger (this escaping is what gave the small spark to the finger and charged the T P in the last experiment), leaving the top uncharged, while the + is _bound_ (Fig. 50). As soon as E C is lifted (Fig. 51) the + spreads all over E C, which is then charged. The +, upon going to the top, charged the pieces of T P (Exp. 80, D), causing them to be repelled. The charge of - upon E S has not been removed, so the operation may be repeated many times before E S must be again electrified. The - electrification on the ebonite acts inductively through E S, drawing up + electrification from the earth. To make this action easier a "sole," or metal conductor, is often placed under the ebonite. =EXPERIMENT 81. To see, hear, and feel the results of inductive influence and polarization.= _Apparatus._ Ebonite sheet, E S (No. 26); insulating table, I T; flannel cloth, F C. =173. Directions.= (A) Thoroughly charge E S with F C. With the right hand bring E S near and parallel to the top surface of I T, but do not let them touch each other. (B) Remove E S, then touch I T to see if it is charged. (C) Repeat (A), and while you hold E S about 1/2 inch from I T, their flat surfaces being parallel, touch I T. Watch for any sparks, and note any peculiar actions of E S. (D) Remove your finger from I T, then withdraw E S; finally touch I T with your knuckle. _=174. Discussion.=_ This apparatus is really the electrophorus upside down. It shows very clearly (1) the escape of the - electrification from I T, by the spark; (2) that the attraction between I T and E S is much greater than before, when this - is removed; and (3) it shows the different steps of the inducing and charging process, as described in Exp. 75, and as shown in Figs. 43 and 44. CHAPTER X. CONDENSATION OF ELECTRIFICATION. =EXPERIMENT 82. To find whether a large surface will hold more electrification than a small one.= _Apparatus._ The insulating table (for details, see Exp. 64); a large tin basin or pan (not furnished); the electrophorus (Exp. 68). =175. Directions.= (A) Test the electrophorus and be sure that it is working properly. (B) As in Exp. 70, see how many good sparks I T will take from E C (which should be recharged at each trial) before the potential of I T is raised so that it equals the potential of E C. (C) Carefully set the basin or pan upon I T, then count the number of good sparks you can pass to it from E C (recharged at each trial). Compare the number of sparks necessary to raise the potential of the large surface until it equals that of E C, with the number found in part (B). _=176. Electrical Capacity.=_ It takes more heat to raise the temperature of a gallon of ice-water to the boiling point, than it takes for a quart of ice-water. You have just seen that a large insulated surface will take more sparks from a charged body than a small one, before its potential is raised to that of the small one, and to that of the charging body. We say that a large surface has a greater _capacity_ than a small one, the shape and other conditions being the same. =EXPERIMENT 83. To find whether the capacity of a given conductor can be increased without increasing its size.= _Apparatus._ Fig. 52. Insulating table. I T (Exp. 64); the extra ebonite sheet, E S (No. 27); the complete flat box, F B (No. 40, 41); the charged electrophorus cover, E C (Exp. 68). Arrange, as shown, I T being insulated from the earth by E S. F B should rest upon a wooden table or other large conductor. =177. Directions.= (A) See how many good sparks I T will take from E C. Re-charge E C at each count, and note the relative sizes of the sparks. (B) Discharge I T by touching it with your knuckle. [Illustration: Fig. 52.] _=178. Condensation; Condensers.=_ As I T easily held more sparks than it would take before (Exp. 70), we say that its _capacity_ has been increased. Its potential didn't increase, because that could not get greater than the potential of E C, the charging body. To describe this state of affairs, we say that the electrification was denser than before, and that it was _condensed_. The _capacity of I T was greatly increased by the presence of another conductor, F B, insulated from I T, but "grounded_." Such a combination, 2 conductors, with a dielectric between them, is called a condenser. A condenser can hold much more electrification at a certain potential than an equal amount of surface can hold when not properly arranged. We might call a condenser a storage battery for static electricity. The capacity of a condenser depends, among other things, upon the area of the conducting surfaces, and upon the thickness and nature of the dielectric. Among the various forms of condensers may be mentioned the Leyden jar, and the fulminating pane. =179. The Leyden Jar= consists of a wide-mouthed glass jar, with tin-foil pasted upon the inside and outside to within 2 or 3 inches of the top. The inner coat or conductor is connected to a knob or ball at the top by means of a chain. To charge the jar, the outer coat is connected with the earth by holding it in the hand, or by resting it upon a table while the electrification is passed to the knob. A _Leyden Battery_ consists of 2 or more connected jars, the object being to increase the area of the surface. The jar is discharged by touching one end of a _discharger_ (§ 188) to the outer coat, and swinging its other end over to the knob, when a bright spark will pass between the knob and discharger. (See Exp. 86.) =180. Fulminating Panes=, or Franklin's Plates, are practically the same as a Leyden Jar. The tin-foil, however, is pasted upon the opposite sides of a pane of glass, a margin of about an inch being left all around. One side of the pane is charged, and takes the place of the inside coat of the jar. The other side is grounded. The pane is discharged by connecting the two sheets of foil. =181. Induction Coil Condensers= consist of sheets of tin-foil separated by sheets of paraffined paper, which act as the dielectric. (See Induction Coils.) =182. Submarine Cables=, with the surrounding water, act like condensers, the result being that the condensing effect slows up the electric current and retards the signals. These make a condenser of enormous capacity. The wires inside form one conductor, and the water the other, while the insulation around the wires forms the dielectric. =EXPERIMENT 84. To study the condensation of electrification.= _Apparatus._ Same as in last experiment, but arrange so that F B and I T shall be near each other at one side; that is, so that the edge of E S shall be even with the edges of the two tins. =183. Directions.= (A) Pass good sparks to I T from the charged E C until something happens. Watch the side where I T and F B are near each other. _=184. Discussion.=_ We may say that the electrification was condensed, in this experiment, until the charge became so great that the _condenser_ suddenly discharged itself. Condensers may be made in many ways, but they all consist of 2 conductors, with a dielectric between them. One conductor is insulated, and receives the charge; the other conductor is grounded. [Illustration: Fig. 53.] =EXPERIMENT 85. To study the action of the condenser.= _Apparatus._ Fig. 53. The insulating table, I T; ebonite sheet, E S (No. 27); flat box, F B, complete (Nos. 40, 41); the electrophorus (Exp. 68). Note that this is really the same apparatus as that just used; both conductors of this condenser, however, are insulated and reversed in position. =185. Directions.= (A) See that your electrophorus works properly, then find out how many good sparks you can pass from E C to F B, recharging E C each time. Note the relative sizes of the sparks, and compare the result with the number taken by the condenser in the last experiment. (B) When F B seems to be fully charged, touch I T with your knuckle. (From your study of induction what should be the result?) (C) Now see if F B will again take good sparks from the charged E C. Pass sparks to F B until it seems fully charged. (D) Again touch I T, then repeat (A) and (B) several times, until a bright spark passes from F B over the edge of E S to I T. _=186. Discussion.=_ The action of the condenser, as clearly shown, depends upon induction. You should now be able to explain and show by diagram the different steps. E C was positively charged (Exp. 80). This also charged F B positively by contact. F B acted inductively through the dielectric, E S, drawing up _some_ of the - in I T, and repelling _some_ of the +. As I T was insulated, this free + electrification could not escape. Before we touched I T, its + and - electrifications, although partially separated, were struggling against this inductive action; and, on account of their strong attraction for each other, our efforts to charge the condenser were retarded. Upon touching I T the free + escaped to the earth. (This was the cause of the spark.) This left _some_ - electrification bound on the underside of E S, and some + bound on the upperside of E S. The capacity of F B was increased by this process, as the + already put into it was very much occupied by the attractions of the induced - just under E S. As more + was given to F B, more - was drawn up under E S and more + was pushed out of I T. This action went on until the two conductors were strongly and oppositely charged. This action goes on continuously when the lower conductor is grounded. The spark between the tins was due to the rushing together of the + and - electrifications; it showed that there was a _momentary current of electricity_. =EXPERIMENT 86. To study the effect of electrical discharges upon the human body.= _Apparatus._ The condenser (Fig. 52), with E S centrally placed so that the apparatus cannot discharge itself; the hairpin discharger, H P D (No. 48); the electrophorus. =187. Directions.= (A) Charge the condenser (Exp. 83) with 10 good sparks from E C, then touch I T (Fig. 52). (B) Recharge the condenser with 10 sparks, then touch F B. Discharge it by again touching I T as in (A). (C) Recharge with 10 sparks; then place your thumb against F B, and quickly swing the first finger of the same hand over to I T, and get a slight shock. (D) Recharge with as many sparks as you think you can stand. (E) Instead of using your hand to discharge the condenser, try the bent hairpin. Keeping one end against F B, swing the other end over near I T. _=188. Shocks; Dischargers.=_ The two conductors being oppositely charged in the condenser (Exp. 85), it is only necessary to place some conductor between them to allow the charges to rush together. Any conductor so used is called a _discharger_. The hand carried the whole current which caused the _shock_. When I T was touched first, the current was obliged to pass through your body, through the floor, and up the table-legs into F B. Always touch the "grounded" conductor first with the discharger, so that you will get a good spark and _not_ a shock. =EXPERIMENTS 87-88. To show the strong attraction between the opposite electrifications in the condenser.= _Apparatus._ Flat box, F B (Nos. 40, 41); sheet of glass, G (No. 38); electrophorus (Exp. 68). The two parts of F B are used for the conductors of the condenser (Fig. 54) for the sake of lightness. The bottoms should be next to the glass, which is used for the dielectric on account of its stiffness. The lower tin should rest upon the table. The glass should be perfectly clean and dry (hot). =189. Directions.= (A) Charge the condenser with 15 or 20 good sparks from E C. (B) Lift the condenser by one corner of G (Fig. 54), being careful not to discharge it. Explain why the lower conductor follows the glass. [Illustration: Fig. 54.] =EXPERIMENT 88.= =190. Directions.= (A) Charge and lift the condenser as just explained (Exp. 87). Fig. 54. (B) With your right hand touch the upper tin alone, then the lower tin alone. (C) Touch both tins at the same time, and note the action of the lower one. _=191. Discussion.=_ This clearly shows how strongly the two electrifications are _bound_ in the condenser. Each refuses to escape to the earth, but they instantly rush together at the first opportunity. The dielectric may be shattered in a very heavily-charged condenser by this strong attraction. [Illustration: Fig. 55.] =EXPERIMENT 89. To show how the condenser maybe slowly discharged.= _Apparatus._ Fig. 55. The condenser (Exp. 83); the carbon electroscope with support (Exp. 58); the electrophorus (Exp. 68). =192. Directions.= (A) Charge the condenser by means of the electrophorus; then hang the carbon so that it can swing between the upper conductor and E C placed as shown. _=193. The Electric Chime.=_ The charging and discharging of the carbon being rapid, it acts like a _chime_ as it taps against the tins. =EXPERIMENT 90. To ascertain the location of the charge in the condenser.= _Apparatus._ The condenser, consisting of flat box, F B (Nos. 40, 41); ebonite sheet, E S (No. 27); insulating table, I T (Exp. 64); (when charging, arrange as in Fig. 52.); the electrophorus; hairpin discharger, H P D (No. 48). =194. Directions.= (A) Charge the condenser with 15 or 20 good sparks from E C. (B) Lift I T away from E S by its insulating handle, and set it upon the table. (It may be necessary to hold E S down.) (C) Lift E S directly up and away from F B. (Lift by 2 corners; do not scrape E S along on F B; do not allow E S to touch your clothing.) (D) Replace E S and then I T by its handle quickly, making the condenser complete again. (E) With H P D see if the condenser still holds a charge. Touch F B first (Exp. 86). _=195. Discussion.=_ As the _conductors_ were completely discharged, being left for a few moments upon the table, it is evident that the opposite electrifications must reside in and upon the _dielectric_. The conductors allow an even and _rapid_ discharge from all parts of the dielectric at the same time. The dielectric is considerably strained when a condenser is heavily charged. This strain, caused by the attraction of the opposite electrifications, may be great enough to break or puncture the dielectric. =EXPERIMENT 91. To find whether any electrification remains in the condenser after it has once been discharged.= _Apparatus._ The condenser (Fig. 52); the electrophorus (Exp. 68); hairpin discharger, H P D. =196. Directions.= (A) Thoroughly charge the condenser. (B) Discharge it with H P D, being sure to touch F B first, and to touch I T for an instant while H P D is against F B. (C) After a few moments use H P D again, and see if you get a slight spark. _=197. Residual Charge.=_ The two electrifications on the opposite sides of the dielectric have such an attraction for each other, when the condenser is charged, that they seem to penetrate, or soak into, the dielectric. These do not completely soak out again at the discharge. The small amount left is called a _residual charge_. [Illustration: Fig. 56.] =EXPERIMENT 92. To study successive condensation; the chime cascade.= _Apparatus._ Fig. 56. This really consists of two condensers, joined by a wire. The upper condenser consists of T F B (No. 41), E S (No. 27), and the insulating table, I T. (See Exp. 64.) The lower condenser consists of the cover of the tin box, C T B (No. 47), the sheet of glass G (No. 38), and B F B (No. 40). The tin box, T B (No. 47), is placed under this to raise it, simply. A wire or hairpin, H P, is hung upon the edge of T F B, its lower end being inside of C T B and not quite touching it. This acts like a pendulum, which is to swing to C T B at the proper time. The source of electrification is E C. =Note.= You have learned that in charging the condenser with the positively charged E C, + electrification is driven from F B into the earth. Can we use this to charge a second condenser? =198. Directions.= (A) Pass 15 or 20 good sparks from E C to the under side of I T (Fig. 56), noting the action of H P. (B) Hold E C in the hand, and, with its insulating handle, poke H P away from the condensers. Do not discharge them. (C) With H P D test the lower condenser for a charge, touching T B first. (D) With H P D touch T F B first (why?), and discharge the upper condenser. _=199. Discussion.=_ A long row of condensers may be charged in this way. There is no advantage in it, as the electrification is merely divided between them. How can two condensers be joined to get the advantages of a large surface? CHAPTER XI. ELECTROSCOPES. _=200. Electroscopes=_ are instruments to show the presence, relative amount, or kind of electrification on a body. (See Apparatus Book, Chap. XVIII, for Home-Made Electroscopes.) The _carbon electroscope_ has been described (Exp. 58). The _pith-ball electroscope_ is made by using pith from elder, corn-stalk, or milk-weed, in place of the carbon. The _gold-leaf electroscope_ is a very delicate instrument. The gold-leaf is supported, as suggested in Fig. 57, at the lower end of a wire conductor which sticks through and hangs from the cork of a glass jar or flask. To the top end of the wire is soldered a ball or disk. The glass jar insulates the gold-leaf, and keeps it dry and free from dust. [Illustration: Fig. 57.] =201. Our Leaf Electroscope= (Fig. 57) is made with aluminum-leaf. Gold-leaf is too delicate for unskilful handling, and aluminum will do for all ordinary experiments. To cut it into any desired shape, place it between two sheets of paper, then cut through paper and all. =202. Construction.= Bend one leg of a hairpin, H P, as in Fig. 57, and slide it onto I T. Hang a wire, W, or another hair pin straightened, then bent, from the horizontal leg of H P. This is to support the "leaves," L, which are made from a strip of aluminum-leaf about 4 in. long and 3/4 in. wide. Moisten the under side of the horizontal part of W with paste or mucilage; press it upon the middle of the strip laid flat upon the table, and then lift W. The leaves should cling to W. Each leaf should be, then, 2 in. long. They should hang close together when not in use. A large chimney, or fruit-jar, may be used to surround the leaves, and to keep currents of air from them. The leaves should not touch the side of the jar when spread. =EXPERIMENT 93. To study the leaf electroscope; charging by conduction.= _Apparatus._ The leaf electroscope (Fig. 57, § 201, 202); ebonite rod, E R (No. 28); flannel cloth, F C (No. 30). =203. Directions.= (A) Thoroughly charge E R, then scrape it along upon I T, noting the action of the leaves, L. (B) See if the leaves will remain spread for some time. (C) Touch I T to discharge it, and note the action of L. _=204. Discussion.=_ No explanation should be necessary for this. Are the leaves charged alike? As they were charged by contact, is the electrification on them + or -? =EXPERIMENT 94. To charge the leaf electroscope by induction.= _Apparatus._ Our electroscope (Fig. 57, § 202); ebonite sheet, E S (No. 27); flannel cloth, F C (No. 30). =205. Directions.= (A) Charge E S with F C, then hold E S above I T (Fig. 57), their surfaces being kept parallel and about 2 or 3 inches apart. Watch the leaves. (B) Withdraw E S. Do the leaves remain spread? (C) Repeat (A), and before removing E S, touch I T. (D) Remove your finger from I T, then withdraw E S. Do the leaves now remain spread? _=206. Discussion.=_ The permanent divergence of L was due to a charge given by induction. (Exp. 76.) As E S was -, what was the kind of a charge in L? Did any electrification go to the electroscope from E S? In (C) what became of the charge in L? Explain why the leaves again diverged in (D). The electroscope was charged with + electrification by taking - out of it. =EXPERIMENT 95. To learn some uses of the electroscope.= _Apparatus._ Our electroscope (Fig. 57, § 202); ebonite rod, E R (No. 28); ebonite sheet, E S (No. 27); glass, G (No. 38); flannel cloth, F C (No. 30). =207. Directions.= (A) With the charged E R charge the electroscope negatively by conduction (Exp. 93). Note the amount of permanent divergence of the leaves. (B) Electrify the glass, which will be +, (or use the + E C), and _slowly_ lower it over I T, noting the effect upon L. Raise and lower G or E C several times. Does G, which has an opposite charge to the electroscope, make L diverge more or less? (C) Discharge the electroscope and recharge as in (A). (D) Slowly lower the charged E S over I T. (E) Slowly lower the palm of your hand over I T. =Note.= If the + G is brought too near the -ly charged electroscope, L will first collapse and then instantly diverge again with a + charge by contact. The _first_ motions should be observed. _=208. Discussion.=_ As a neutral body causes a slight _collapse_ of the leaves, as well as a body charged positively (when the charge in the leaves is -), an increase of divergence is really the only sure test to tell how a body is charged. The - leaves collapse when a + body is brought near I T, because the - in them is drawn up towards the body. The leaves diverge more when a - body is brought near, because the - in I T is repelled into them. _=209. The Proof-plane.=_ Since charges of static electricity reside upon the outside of conductors, it is an easy matter to take samples of the electrification. This may be done with a little instrument called a carrier, or proof-plane. It consists of a small conductor with an insulating handle. A ring or coin may be used for the conductor, and a silk thread for the handle. By touching the carrier to any charged body, it, also, becomes charged; and the nature of the charge may be determined by the use of a previously charged leaf electroscope (Exp. 95). A delicate gold-leaf electroscope would be ruined by coming in contact with a heavily charged body. The carrier allows a small sample to be tested. CHAPTER XII. MISCELLANEOUS EXPERIMENTS. [Illustration: Fig. 58.] =EXPERIMENT 96. To show that friction always produces two kinds of electrifications.= _Apparatus._ Fig. 58. The carbon electroscope (Exp. 58); flannel cloth, F C, doubled twice to make 4 thicknesses (see Fig. 58); ebonite sheet, E S (No. 26); ebonite rod, E R (No. 28); charged electrophorus cover, E C. =210. Directions.= (A) Vigorously rub E S with F C (folded as in Fig. 58). See if you can discover any attraction between them. (B) Rub E S again, but do not lift F C from it with the hand alone. Slip E R under the top fold in F C (Fig. 58), and lift F C straight up from E S. Do not let F C touch the table or your hand. (C) See if F C is charged, using 2 or 3 different tests. (D) Charge the electroscope with F C until the carbon is strongly repelled. (E) Bring the positively charged E C slowly near the carbon, and note the result. (F) Slowly bring the negatively charged E S near the carbon that has been charged by contact with F C. _=211. Discussion.=_ This experiment showed that while the ebonite was negatively charged, the flannel was positively charged. One kind of electrification is never produced without the other. It can also be shown that the two kinds are equal in amount. =EXPERIMENT 97. To show "successive sparks."= _Apparatus._ Fig. 59. The electrophorus (Exp. 68); the extra ebonite sheet, E S (No. 27); three coins (marked A, B, C, in Fig. 59). The coins should nearly touch each other, and rest upon E S. A part, only, of the electrophorus cover is shown. =212. Directions.= (A) Thoroughly charge the electrophorus cover. (B) Place your finger upon the coin marked A, to "ground" it, then quickly touch the coin C with the charged cover, at the same time watching for sparks between the coins. If you cannot see the sparks, darken the room a little, and look at the center coin, B, while doing the experiment. [Illustration: Fig. 59.] [Illustration: Fig. 60.] =EXPERIMENT 98. To show to the eye the strong attraction between a charged and a neutral body.= _Apparatus._ The flat box, F B (Nos. 40, 41); the electrophorus (see Exp. 68). =213. Directions.= (A) Stand F B upon its edge upon a level table, then bring the charged electrophorus cover near it. (B) Instead of the above, use light hoops made of paper, eggshells, feathers, sawdust, etc. =EXPERIMENT 99. To feel the strong attraction between a charged and a neutral body.= _Apparatus._ Fig. 60. The flat box F B (Nos. 40, 41); the electrophorus (Exp. 68). =214. Directions.= (A) Hold F B in the left hand, as shown, then _slowly_ bring near it the charged cover, at the same time looking between them so that you can keep them the same distance apart all the way round. (B) Bring them near enough to allow a spark to pass from E C to F B. =EXPERIMENT 100. The human body a frictional electric machine.= _Apparatus._ Yourself; a carpet; a room with dry air, easily had on a cold winter's day. =215. Directions.= (A) Scrape your feet along upon the carpet, then quickly touch your finger to some conductor, as, for example, a friend's nose. (B) It is possible to light the gas by the above process. Have a friend turn on the gas just before you bring your finger to the jet, and be sure that the spark from your finger passes through the gas on its way to the conductor, the jet. (C) Bring your finger quickly near a small piece of tissue paper after you have scraped your feet along to charge your body. _=216. Static Electric Machines=_ are used to produce large quantities of static electricity. In the early forms, the electrification was produced by friction. Modern machines depend upon the principle of induction. The electrophorus (Exp. 68) is really a very simple form of induction machine. The potential of these machines is very great, as the spark may jump many inches. Thousands of Galvanic cells would be needed to make a spark an inch long. When the spark passes through the air it meets with an extremely high resistance, as air practically insulates ordinary electricity. This high resistance in the circuit reduces the strength of the current. While the potential is very high, the strength of the current is very low. (See Ohm's Law.) CHAPTER XIII. ATMOSPHERIC ELECTRICITY. _=217. Atmospheric Electricity.=_ The air is generally electrified, even in clear weather. Its charge is usually +. Clouds are sometimes +, and sometimes -. The cause of atmospheric electricity is not thoroughly understood. It is thought, by some, to be due to the friction of the particles of vapor upon each other. It is also thought that the evaporation of sea water, and the friction of winds, produce it. _=218. Lightning.=_ Benjamin Franklin, in 1752, proved by his famous kite experiment that atmospheric and frictional electricities were of the same nature. By means of a kite, the string being wet by the rain, he succeeded, during a thunder-storm, in drawing sparks, charging condensers, etc. Lightning may be produced by the passage of electricity between clouds, or between the cloud and the earth, which, with the intervening air, have the effect of a condenser. If one cloud is charged, it acts inductively upon another, producing in it the opposite kind of electrification. When the attraction between the two electrifications becomes great enough, it overcomes the resistance of the air, and lightning is produced. The flash is practically instantaneous. The direction taken seems to depend upon the conditions of the surrounding air. It has generally a zigzag motion, and is then called _chain lightning_. The air in the path of the electricity becomes intensely heated; it is this effect, and not the electricity which we see. In hot weather flashes are often seen which light up whole clouds, no thunder being heard. This is called _heat lightning_, and is generally considered to be due to distant discharges, the light of which is reflected by the clouds. The _potential_ of the lightning spark is beyond all calculation. The spark jumps through miles of air, which is, really, an insulator. This spark represents billions and billions of volts. _=219. Thunder=_ is caused by the violent disturbances produced in the atmosphere by lightning. The nature of the sound depends, among other things, upon the distance of the observer from the discharge, and upon the length and shape of the path taken. Clouds, hills, and other objects produce echoes, which also modify the original sound. It takes nearly five seconds for the sound to travel one mile. _=220. Lightning-Rods=_, when well constructed, often prevent violent discharges of atmospheric electricity. They have pointed prongs at the top, which allow the negative of the earth (which is being attracted by the cloud when it is positively charged) to pass quietly into the air above; this neutralizes the cloud. In case of a discharge, the rods aid in conducting the electricity to the earth. _=221. Causes of Atmospheric Electricity.=_ There are several theories about this. Some think that it is due to the rotation of the earth, different parts being acted upon differently by the heat of the sun. Some claim that the evaporation of the water in the ocean produces it, while others say that the electrification is produced in the clouds by the friction of their particles upon each other. The matter has not been settled. _=222. St. Elmo's Fire=_ Electrification from the earth is often drawn up through the masts of ships to neutralize that in the clouds (see § 220), and, as it escapes from the points of the masts, light is produced. This may be clearly shown by repeating Exp. 71 in the dark; the head of the pin (Fig. 39) will represent the end of a mast, and the charged electrophorus cover will be the charged cloud. _=223. Aurora Borealis=_, also called Northern Lights, are luminous effects often seen in the north. They often occur at the same time with magnetic storms, at which times telegraph and telephone work may be disturbed. The exact cause of this light is not known, but it is thought by many to be due to disturbances in the earth's magnetism, caused by the action of the sun. CURRENT ELECTRICITY. PART III.--CURRENT ELECTRICITY. CHAPTER XIV. CONSTRUCTION AND USE OF APPARATUS. =Note.=--Before taking up the study of cells and the electric current, let us perform a few experiments in order to understand the construction and use of some of the apparatus needed for such study. A dry cell will be used as the source of the electricity for these first experiments, because it is convenient. You will understand its action later. Use this cell only as directed; improper use of it might spoil it. [Illustration: Fig. 61.] =EXPERIMENT 101. To study the effect of the electric current upon the magnetic needle.= _Apparatus._ A compass (No. 18); a dry cell, D C (No. 51); wires with spring connectors attached (§ 226) for making connections. Fig. 66 shows a plan or top view of the arrangement. Any other form of cell will do in place of D C. =226. Electrical Connections.= One must constantly join wires, connect wires with apparatus, or connect one piece of apparatus to another, to make the proper electrical connections. A very simple method of connections has been used in all the apparatus described in these experiments. A little arrangement which we shall call a spring connector, S C, (Fig. 61), gives us a means of quickly making connections; that is, it does away with expensive binding-posts. It is made of brass, nickel plated, and may be used anywhere without affecting the magnetic needle. Six or eight wires, about No. 24 gauge, each about 1-1/2 ft. long, should be prepared with a connector at each end. You may use wire furnished (No. 53). Scrape the insulation from the ends of the wires for about 1-1/2 inches, then twist the bare ends around the connectors as shown in Fig. 61. The wire should pass around tightly at least 4 or 5 times and then be twisted a little, as shown, to help tighten it. Do not put it on so poorly or in such quantity that the part, B, will spread. =227.= Fig. 62 shows how the connector should be slipped upon a thin piece of metal, M, like that on the galvanoscope, for example. The wire, W, from the apparatus itself is permanently fastened under the head of the screw, S, while the wire from any other apparatus is one of those kept on hand as above mentioned and connected with S C. [Illustration: Fig. 62.] [Illustration: Fig. 63.] [Illustration: Fig. 64.] =228.= Fig. 63 shows how several wires may be quickly joined, electrically, by slipping the connectors at their ends upon a thin metal plate, M P, which may be a piece of tin, zinc, copper, etc. M P should not be too thick. In case the connectors become too much spread to pinch the plate, squeeze the part, A, a little more together. =229.= Fig. 64 shows the method of connecting with the special form of binding-post used, for example, upon the resistance coil, R C. The end, C, of S C, is pressed down into the tube, T, until you feel, by moving it, that it springs firmly against the sides of the tube. In case you wish S C to fit very tightly in T, one of the legs may be slightly bent outwards. [Illustration: Fig. 65.] =230.= The connector may be used in still another way; that is, by pushing the part, A, into the hole of an ordinary binding-post, (Fig. 65), and using it just the same as a thick wire. =231. Directions.= (A) Stand the compass and D C near each other (Fig. 66). Attach one end of an insulated copper wire, C W, to the binding-post, C, which is on the carbon plate of the cell. Do _not_ join the other end to the other binding-post, Zn, of the zinc plate. (B) With the left hand hold C W above and near the compass-needle, and in the N and S line, so that it will extend over the entire length of the needle. (C) Take the free end of C W in the right hand and touch binding-post, Zn, for an instant only, watching the needle. Repeat. _=232. Current Detectors.=_ We know that a magnet can act, by induction, through the air upon a piece of iron or upon another magnet. The deflection of the needle in this experiment shows that there must be a magnetic field around a wire carrying a current. This fact is of the greatest possible importance. The simple magnetic needle, when used as above, becomes a detector of electricity. [Illustration: Fig. 66.] [Illustration: Fig. 67.] =EXPERIMENT 102. To study the construction and use of a simple "key."= _Apparatus._ A key, K (No. 55) (§ 233); a dry cell, D C, (No. 51); a compass, O C (No. 18). _Arrange_ as shown in Fig. 67, which is a top view or plan. Connect the pieces of apparatus with wires and spring connectors (§ 226). Binding-post, C, is joined to I (in) of the key; O (out) of key is joined to binding-post, Zn, the wire, C W, passing directly over and near O C, which is to be used as a detector. The current cannot pass until the lever, L, is pressed. A metal plate, M P, is used to connect two short wires (§ 228) in case C W is not long enough. [Illustration: Fig. 68.] =233. A key= is merely a piece of apparatus by which the circuit can be conveniently and rapidly opened and closed at the will of the operator; that is, by it the electricity can be quickly turned on or off. Fig. 68 shows a simple form of key. To the base, B, are fastened two metal pieces or straps, the upper one, L, being the lever or key proper. The front end of L is raised above O, so that the two do not touch each other unless L is firmly pressed down. A screw, S, keeps L from springing too far above O. For convenience we shall suppose that the wire leading to the key joins it at I (in); the wire _from_ the key is joined to O (out), by means of connectors (§ 226). The key may be put into any circuit by first cutting a wire and then joining the ends to I and O. Spring connectors make the best connections with this form of key. (For Home-Made Keys see Apparatus Book.) =234. Directions.= (A) The magnetic needle being directly under the wire, press L down for an _instant only_ and note the action of the needle. (B) Press L again, hold it down for 3 seconds, not over that, and watch the needle. _=Discussion.=_ The key allows us to easily regulate the length of time during which the current passes. This experiment shows, also, that the magnetic field about the wire disappears as soon as the current ceases to pass. [Illustration: Fig. 69.] =EXPERIMENT 103. To study the construction and use of a simple "current reverser."= _Apparatus._ A dry cell, D C (No. 51); a compass, O C (No. 18); a current reverser, C R (No. 57) (See § 235); an insulated copper wire, C W, 2 or 3 feet long, with spring connectors joined to its ends (§ 226). _Arrange_ as in Fig. 70. The wire, C W, leading from X should be held by the left hand so that it will be just above (or below) and parallel to the magnetic needle. The current cannot pass through C W until one of the straps or levers on C R is pressed. (See Apparatus Book for Home-Made Reversers.) =235. The Current Reverser.= (No. 57.) To the wooden base (Fig. 69) are fastened four metal straps, each turned up at the end so that spring connectors (§ 227) can be slipped on to make electric connections with other pieces of apparatus. Suppose that at C and Z connections are made with the carbon and zinc of the cell, by means of wires and spring connectors (§ 226). The current comes from the cell to C. As the two straps, 2 and 3, press firmly up against strap 4, and do not touch 1, it is evident that no current can pass from 1 to 2 or to 3 until they are pressed down upon 1. Two wires are joined by spring connectors to 2 and 3 at their turned up ends, X and Y, and these wires lead to any desired instrument. [Illustration: Fig. 70.] =236. Directions.= (A) Press down lever 2 (Fig. 70), for an instant only, at the same time noting carefully in which direction the N pole of the needle is deflected. (B) After allowing lever 2 to spring up again, and after the needle comes to rest, press down lever 3 for an instant, watching the needle. Is the N pole of the needle deflected in the same direction as it was in (A)? _=237. Discussion.=_ The reverser gives us a quick and easy means of reversing the current which is to pass through any desired instrument, first in one direction and then in the opposite direction. Suppose (Fig. 69) that the current enters C R at C, as it does when C is joined to the carbon of the cell; the current can go no farther until one lever is lowered. If lever 2 (Fig. 69) be now pressed down, as in part (A), the current will pass along 2, which does not now touch 4, out through X to a coil of wire or any instrument, and back to the reverser by the wire joined to Y. It will then pass from 3 onto 4, to Z, and back to the Cell; that is, the current enters C W at X. When lever 3 is pressed, the current still entering C R at C, the electricity will pass onto 3 and out at Y, and back through X, 4 and Z to the cell. The current, then, can be made to pass out of X or Y at will by pressing the proper lever. This experiment also teaches something about currents, but these will be discussed later. [Illustration: Fig. 71.] =EXPERIMENT 104. To study the simple current detector.= _Apparatus._ The compass (No. 18); dry cell, D C (No. 51); current reverser, C R (No. 57); copper wire, C W, a few feet long, with spring connectors on its ends. (See Apparatus Book, Chapter XIII, for Home-Made Detectors.) =238. Directions.= (A) Join the ends of the wire to X and Y of the reverser, C R, as in the last experiment. Coil up C W so that you can hold the coil with your left hand, as shown in Fig. 71, the magnetic needle being inside of it and parallel to it. (B) Press lever 2 of the reverser for an instant only. Is the needle deflected more or less than it was when the wire simply passed over or under it once? (C) Reverse the current through C W by pressing lever 3, and note the result. (D) Get clearly in mind which way the N pole of the needle is deflected when the current enters C W at X, also when it enters at Y. _=239. Discussion.=_ The current passed _over_ the needle in one direction, and _under_ it in the opposite direction; that is, the part of the wire above _helps_ that below. Each turn of the wire increases the strength of the magnetic field about the coil, and helps to deflect the needle. In this way, by increasing the number of turns, detectors may be made that will show the presence of very weak currents. The magnetic fields about wires and coils will be studied in a later chapter. [Illustration: Fig. 72.] =EXPERIMENT 105. To study the construction and use of the simple galvanoscope.= _Apparatus._ The galvanoscope, G V, complete (No. 58), described in § 240-246; dry cell, D C (No. 51); current reverser, C R (No. 57) (§ 235); wires, with spring connectors, to join the different pieces of apparatus (§226). (See Apparatus Book, Chapter XIII, for Home-Made Galvanoscopes.) =240. The Galvanoscope= (Fig. 72) is more than a mere detector of electricity. With it we shall be able to study, more fully, cells, currents, etc., etc. We must first understand its construction. =241. The Coil-support=, C S, is fastened to the cross-piece, C P, on which are the 3 binding-posts or coil-ends, L, M and R (left, middle, right). The legs, G L, are screwed to C P in such a way that C P is held a little above the table: this allows C S to be tipped to the front or rear to adjust it vertically. On account of the peculiar arrangement of the legs, the galvanoscope can be made to stand firmly, even upon uneven surfaces. The screws holding G L should not be put in far enough to tear the threads in the wood, C P. =242. The Galvanoscope Coils=, G C, are two in number, both being fastened to the coil-support, C S. The first coil has five turns of wire, its ends being fastened to L and M; the other coil has _ten_ turns, with ends at M and R. The current can, at will, be made to pass through 5, 10 or 15 turns of wire by making the proper connections. Suppose that we have two wires direct from a cell, or from the current reverser, with spring connectors on them so that we can slip them onto L, M or R, which stand for left, middle or right. When the wires are joined to L and M the current can pass through but 5 turns; when joined to M and R it will go through 10 turns; and when to L and R it will pass through the entire 15 turns. When the current enters the galvanoscope at L and passes out at M or R, it will pass through the turns of wire from left to right, at the top; that is, it will pass in a "clockwise" direction. =243. The Compass-needle=, furnished with O C (No. 18), will do also for this galvanoscope. It should be placed upon the pin-point after fixing on the pointers (§ 246). The length of the needle should be parallel to the plane of the coil when no current passes; that is, the coil and coil-support should be in the N and S line. The needle can be centered in regard to right and left, and in regard to up and down, by properly adjusting the position of the pin-point support, P P S; this is held firmly to C S by two spring-connectors. By removing S C, the support, P P S, may be raised or lowered. =244. To place the coil= in the N and S line, simply swing the galvanoscope bodily around, at the same time looking down upon the needle, until the length of the needle becomes parallel to the coil-support. When once carefully adjusted N and S, a line may be drawn upon the table as a guide for its position in future experiments. The coil should stand in a vertical plane, and this straight up and down position can be easily adjusted. To place the coil in the E and W line, turn it until the pointers are at the 90° (90 degree) marks,--the 0° (zero degree) marks remaining, of course, as described above. =245. The Degree-Card, G D C= (Fig. 72) has a dot at its center, to show where to make a pin-hole for the pin that supports the compass-needle. With this you can tell how many degrees the needle is deflected when the current passes. This card, G D C, should be pressed down over the pin-point. The zero points of G D C should be N and S, also, when the coil is in that position; that is, they should be in the plane of the coil. The pointers on the needle (§ 246) will then be at O, when the needle is at rest, no current passing through the coils. (See Apparatus Book § 272 for Home-Made Degree-Card.) G D C may be held permanently in position after it is adjusted, by sticking a short pin through it into P P S. Do not let this pin interfere, however, with the swinging of the needle. [Illustration: Fig. 73.] =246. Pointers= (Fig. 73) should be fastened to the needle, in order to make the readings of degrees accurate. Fasten to the compass-needle a piece of No. 30 insulated copper wire, as shown. It may be cut to the proper length after it is wound around the needle. See that the wire does not touch the pin when needle is in place; balance needle by cutting a little from the heavier end of wire with shears; bend the ends of wire so that they are at opposite sides of the degree-card, both pointing at O, for example. The needle must swing freely, be nicely balanced, and the wire must not touch pin or degree-card. [Illustration: Fig. 74.] =247. Directions.= (A) Arrange as in Fig. 74, the coil being N and S (§ 244). Join the ends of the wires, 2 and 3, with the 5-turn coil of G V as shown. Wire, 2, is connected to L (Fig. 72). Press lever 2 of C R (Fig. 69) for an instant, watching the compass-needle and noting how many degrees it swings the first time. Get thoroughly in mind the direction in which the N pole of the needle is deflected when the current passes around G C in a "clockwise" direction. There must be no magnets, iron, or pieces of steel within 3 feet of A G. (B) Press lever, 3, for an instant, watching the needle. The current will now pass in an "anti-clockwise" direction. Is the needle deflected about the same number of degrees as in (A)? (C) Change the ends of the wires, 2 and 3, to the 10-turn coil (§ 242) and repeat (A) and (B). (D) Change 2 and 3 to L and R (Fig. 72), thus allowing the current to pass around 15 turns; then repeat (A) and (B). _=248. Discussion; True Readings.=_ Is not possible to get the magnetic needle, M, exactly in the center of G C; the pointers will not exactly be in the axis of M; the coils will not be exactly N and S: hence, if you pass a certain current through the coil and the pointer reads 20 degrees, you will find, if you reverse the current, that the pointer may read 24 degrees on the other side of the zero mark. To get the _true reading_, average the two, in this case the average being 22 degrees. The galvanoscope gives us an instrument with which we can study, more fully, cells, currents, etc. =249. Note of Caution.= It has already been stated that the compass-needle should be in the center of the coil (§ 243), and that the coil should be in the N and S line (§ 244). In addition to the above, see that there are no magnets near G V, when using it; tap G V occasionally to be sure that the needle swings freely, hold the eye directly over the pointers when reading degrees; the pointers should be at zero when no current passes through G V; be sure that the electrical connections are good. There are several sources of error in taking readings, and in all the quantitative experiments given. The author takes it for granted that such errors will be looked out for by the teacher. [Illustration: Fig. 75.] =EXPERIMENT 106. To study the construction and use of a simple astatic needle.= _Apparatus._ Two unmagnetized sewing-needles (No. 1); horseshoe magnet, H M (No. 16); piece of stiff paper doubled and cut as in Fig. 75; a pin-point on which to support the paper. The pin may be stuck through a cork, or that of O C (No. 18) may be used. =250. Directions.= (A) Draw each needle across the N pole of H M five times from point to head (Exp. 9). This should make them of nearly equal strength, both points being N poles. (B) Stick the needles through the paper as shown, the N poles being at the same end of the paper. Balance the paper upon the pin-point. Has this combination a strong or weak pointing-power? (C) Turn one of the needles end for end. Again test the pointing-power. _=251. Discussion; Astatic Needles.=_ By arranging the needles so that their poles oppose each other, the pointing-power becomes almost nothing. This sort of a needle is needed in some experiments in electricity. Their magnetic fields are still retained. The combination is called an _astatic needle_; it is used to detect very feeble currents. The more nearly equal the magnets are in strength, the better. They are usually arranged with one above the other (Fig. 76). [Illustration: Fig. 76.] [Illustration: Fig. 77.] =EXPERIMENT 107. To study the construction and use of a simple astatic galvanoscope.= _Apparatus._ An astatic galvanoscope, A G (No. 59) (§ 252-254); dry cell, D C (No. 51); current reverser, C R (No. 57) (§ 235); wires for connections (§ 226). _Arrange_ as shown in Fig. 80, which is a top view. The wires from C R are connected to the binding-posts of A G at the back, the spring connectors being slipped into them (§ 229). =252. Construction of the Astatic Galvanoscope.= When not to be used for a long time, or for shipping, the legs, A (Fig. 77) may be removed, and the whole packed inside of the box, B. The _Coil_, C, has a resistance of about 5 ohms, and is fastened to the coil-support, C S. The ends of the coil are permanently fastened to the binding-posts, L and R (left and right). The ends are so arranged that when the current enters at L it will pass around the coil in a clockwise direction. =253. The Astatic Needle= (Exp. 106) is supported by a small thread, T, which is tied to the thread-wire, T W. This T W springs into an eyelet, E, which, in turn, rests in a hole made in the end of B. E should turn easily in the hole, but it should not wabble. Fig. 78 shows a sectional view of the coil and needle. The wire, W, should be bent, as shown, so that the magnets can be as near the center-line of C as possible. Fig. 79 shows a front view of the needle. As a matter of convenience it will be best to arrange the poles of the needles, as shown, to agree with the descriptions of the experiments. To keep the needle from being affected by air currents, the glass plate (No. 38) may be placed in front of the box, B. Stand it upon the legs, A, and tie a string around it, and B, to hold it in place. [Illustration: Fig. 78.] [Illustration: Fig. 79.] =254. Adjusting the Needle.= As T is tied to T W, the needle may be swung completely around by turning T W. This should be done until the length of the needle is parallel to the turns of C. The up and down position of the needle should be fixed as nearly as possible when fastening T to T W, the exact place being finally fixed by raising or lowering T W through E. The spring in T W should hold it firmly in E after adjustment. The wire, W, joining the needle-magnets should not touch the coil. It may be made to just swing free from C by tilting the box forward or backward a little. The construction of the legs, etc., makes it possible to tilt the box, and to make it stand firmly upon an irregular surface. [Illustration: Fig. 80.] =255. Directions.= (A) See that there are no magnets within 3 feet of A G. Test the astatic needle, after you have it properly suspended, to convince yourself that it does not try to swing around in a N and S line. In case the needle-magnets have been in contact with other magnets, or are not equally magnetized, remagnetize them as directed in Exp. 106. They must remain in any position given them by turning T W. Finally, bring them parallel to the turns of the coil. (See § 254.) Arrange as in Fig. 80. (B) Press lever 2 of C R (§ 235) for an instant only. This allows the current to enter A G at L. Repeat several times until you thoroughly fix in your mind the direction in which the right-hand end of the needle is deflected. Does the needle jump suddenly when the current passes? (C) Press lever 3 for an instant only. Study the result. _=256. Astatic Galvanoscopes.=_ It is evident that in the ordinary current detector (Exp. 104), the pointing power of the needle has to be overcome by the magnetic field about the coil, before the needle can be forced from its N and S line. Very weak currents will not visibly move the needle in ordinary detectors. To make a sensitive instrument we must have strong fields about both the needle and coil, and we must, at the same time, decrease the pointing power of the needle. Both of these things are accomplished by using an _astatic needle_ in connection with a coil containing considerable wire. The uses of the astatic galvanoscope will be studied more fully in later experiments. CHAPTER XV. GALVANIC CELLS AND BATTERIES. =EXPERIMENT 108. To study the effect of dilute sulphuric acid upon carbon and various metals.= _Apparatus._ A piece each of copper and iron wire 4 in., (10 cm.) long; two narrow strips of sheet zinc (No. 60), one being amalgamated (§ 257); a carbon rod (No. 64); a tumbler (No. 65), partly filled with dilute sulphuric acid, (§ 258); mercury (No. 52). =257. To amalgamate= one of the above zinc strips is to coat it with mercury. Remove all jewelry from the hands before proceeding. Wash the zinc with water, and with a cloth remove all dirt from its surface. Amalgamated zinc is very brittle, so lay it flat upon a piece of board or upon a plate, after dipping it for an instant in the dilute acid. Place a small drop or two of mercury upon the strip, and rub the mercury about upon both sides of the zinc with a cloth made wet with the dilute acid. Mercury clings strongly to zinc or tin, so you may use a narrow piece of either as a spoon to carry a small drop from the supply to the zinc. Tap it upon the zinc to dislodge the drops. Do not get on too much mercury, just enough to coat it, or, at least, that part of it that will be under the acid. Be careful not to break the thin zinc when amalgamating it, as it gets very brittle. It should look bright. (See Apparatus Book § 32, 33.) _Note._ Should any mercury get upon copper plates it may be removed by heating them in a flame. =258. Dilute sulphuric acid=, for these experiments, should be made by mixing 1 part, by volume, of concentrated acid, with 20 parts of water. Do not let the acid get upon clothes or carpets. Do not add water to acid. Mix by _slowly_ adding the acid to the water in a glass or earthen dish, stirring at the same time. Mix over a sink or out of doors. (For fuller details see App. Book; § 21, 22, 23, 24, 25.) To save time, make at least a quart of the mixture, bottle, and label it for use. =259. Directions.= (A) Bend over one end of each of the wires and metal strips, and hang them upon the edge of the tumbler (Fig. 81), so that their lower ends shall be in the acid. Do not let them touch each other. Stand the carbon rod in the acid. If there is no visible action upon any of the above substances, add a few drops of concentrated acid to the tumbler. Note carefully what takes place in the tumbler, and state which of the substances are dissolved, which simply made brighter, and which not acted upon at all. _=260. Discussion.=_ The bubbles of gas that arise from the zinc when it dissolves are hydrogen, and they indicate that a vigorous chemical action is going on in the tumbler, and that the zinc is being eaten away. [Illustration: Fig. 81.] [Illustration: Fig. 82.] =EXPERIMENT 109. To study the effect of dilute sulphuric acid upon various combinations of metals.= _Apparatus._ The same as in the last experiment. A small piece of amalgamated zinc, however, will be better than the whole strip. =261. Directions.= (A) Twist one end of the clean copper wire around the small piece of amalgamated zinc (Fig. 82). Hold one end of the wire in the hand and dip the combination into the acid. What takes place? Watch the surface of the copper, remembering that each, alone, was not acted upon by the acid (Exp. 108). (B) Use the clean iron wire in place of the copper wire, and repeat (A). Watch the surface of the iron. (C) With a string or thread tie a small piece of well amalgamated zinc to the carbon rod (Fig. 82), then dip the combination into the acid. Watch the surface of the carbon. _=262. Discussion.=_ While amalgamated zinc is not rapidly dissolved by dilute sulphuric acid, a vigorous action of some kind takes place when it is in contact with another metal or with carbon in the acid. The bubbles of hydrogen that are liberated do not seem to come from the zinc; they appear to grow, in the fluid, directly at the surface of the copper, iron, or other metal used with the zinc. This shows that something besides the mere dissolving of a metal takes place. Can we arrange our apparatus so that we can get some useful results from this action? =EXPERIMENT 110. To study the construction of a simple Voltaic or Galvanic cell.= _Apparatus._ A narrow strip of zinc (No. 60), amalgamated as directed in § 257. (An amalgamated zinc rod (No. 74) may be used in place of the strip); a narrow strip of sheet copper (No. 67); the tumbler of dilute acid of Exp. 108; a flexible copper wire about 2 feet long, with spring connectors (No. 54) attached to its ends. (See Electrical Connections, § 226.) [Illustration: Fig. 83.] =263. Directions.= (A) Holding the amalgamated zinc strip in one hand and the copper strip in the other (Fig. 83), dip them into the acid, but do not let them touch each other. Note any chemical action. (B) Touch the copper and zinc together, _below_ the surface of the acid. Watch the copper. (C) Separate the lower ends of the strips, then touch them together _above_ the acid. Anything still happen to the copper? (D) Slip one spring connector with the attached wire upon the zinc strip, then stand the strips in the tumbler, so that they can not touch each other. Now touch the copper strip with the free end of the wire, at the same time watching the copper. (E) Raise the wire from Cu, touch it to Cu again, and repeat several times until you are sure that something takes place every time the wire touches Cu. _=264. The Electric Current.=_ Something must happen in or through the wire, and it can only happen when the two metals are joined in some way. This peculiar, invisible action in the wire is called the _electric current_, and such an arrangement is called a _Galvanic cell_. _=265. Source of the Electrification.=_ When two different metals are placed in acid they are electrified unequally by chemical action. Each has a higher potential than the acid, but their potentials are not the same. This electrification tends to pass from the place of higher to the place of lower potential, and the conducting wire allows this transfer to take place. As the difference of potential is kept up by the continued chemical action, the current is continuous, and not simply instantaneous, as in discharges of frictional electricity. As heat is produced by the burning of coal, so electrification is produced by the chemical burning of zinc. Chemical energy is the source of electrification in the Galvanic cell, just as muscular energy was the source of the electrification in the experiments with frictional electricity. _=266. The Electric Circuit; Open and Closed Circuits.=_ The simple Galvanic cell just used, together with the wire which joined the metal strips, is called an _electric circuit_. If the current should pass through a telegraph instrument, for example, on its way from one strip to the other, the telegraph instrument would also be in the circuit. When the wire is cut or removed from one metal strip, the circuit is said to be _open_--that is, we have an _open circuit_. When the current passes, the circuit is _closed_. We also say _make_ and _break_ the circuit, and that the circuit has been _broken_. _=267. Plates or Elements.=_ The copper and zinc strips are called the _plates or elements_ of the cell. The zinc, Zn, Fig. 84, is dissolved by the acid, and is called the positive plate (+ plate). The copper, Cu, is the negative plate (- plate). The copper is also called the _cathode_, and the zinc the _anode_. _=268. Direction of Current.=_ It has been agreed, for convenience, that _in_ the cell the current passes from the zinc through the liquid to the copper, where the hydrogen bubbles are deposited. It then passes through the wire, or other conductor furnished, back to the zinc, through the liquid to Cu again, and so on around and around thousands of times per second. The current really starts at the surface of the zinc, where the chemical action is. When carbon and zinc are used, the action and direction of the current are the same, carbon being the - plate. [Illustration: Fig. 84.] _=269. Poles or Electrodes.=_ If the wire were cut, the electricity coming from the + plate would be stopped at the end of the wire marked +, Fig. 84, after passing through the acid and up Cu. This end of the wire is called the + _pole or electrode_ (positive). The end of the wire joined to Zn is called the - _pole_ or _electrode_; that is, the + electrode is the end of the wire attached to the - plate. The tops of Cu and Zn may be considered electrodes. The top of Cu is the + _pole_ of the cell, while Cu is the - _plate_. =270. Chemical Action in the Simple Galvanic Cell.= The chemical formula of sulphuric acid is H_{2}SO_{4} (read H, 2, S, O, 4). This means that it is a compound of hydrogen (H), sulphur (S), and oxygen (O). The H_{2}SO_{4} stands for _molecule_ of acid, and the small figures show that the molecule is made up of 2 _atoms_ of hydrogen (H_{2}), one of sulphur (S), and 4 of oxygen (O_{4}). The atoms are held together by _chemical attraction_ or _affinity_. There is a stronger chemical affinity between zinc (Zn) and SO_{4} than between H_{2} and SO_{4}; so, as soon as the Zn gets a chance, as it does in the cell, it drives out the H_{2}, and it takes its place in the molecule. This chemical _reaction_ may be shown by the following chemical _equation_: Zn + H_{2}SO_4 = ZnSO_4 + H_2. Zinc and sulphuric acid produce zinc sulphate and hydrogen. The zinc sulphate produced weakens the effect of the acid; in fact, the acid has to be renewed occasionally, as it is changed to the sulphate which remains in solution. =271. Action in Cell Using Impure Zinc.= The above action takes place in the cell when impure zinc is used, even when no current passes, heat being produced by the reaction instead of useful electricity. (See Local Currents.) =Action in Cell Using Pure Zinc.= When pure zinc (or impure zinc that has been properly amalgamated) is used in the cell, it dissolves, or is eaten away, only when the current passes. It should be noted that the bubbles of hydrogen do not even then appear at the zinc; they are not seen throughout the body of the liquid. There seems to be an unseen transfer of hydrogen from the zinc, through the liquid, to the copper (or other - plate used), and it appears there in the shape of bubbles. The larger the quantity of pure zinc dissolved, the stronger the current, and the larger the amount of hydrogen produced. As the zinc dissolves it parts with its latent energy, and this energy forces the electric current through the circuit. While the hydrogen of the decomposed acid makes its way towards the - plate, the SO_4 part of it travels towards the Zn plate, where the ZNSO_4 is formed. (See § 270.) =EXPERIMENT 111. To see what is meant by "local currents" in the cell.= _Apparatus._ Tumbler of dilute sulphuric acid. (§ 258); strip of unamalgamated zinc; crystal of copper sulphate (blue vitriol) (No. 86); a galvanized iron nail (No. 69), this being iron covered with zinc. =272. Directions.= (A) Hold the nail in the acid for a few seconds, and note result. (B) Rub the copper sulphate upon the zinc simply in one spot, then place the zinc in the acid, noting the result at the spot. _=273. Local action; Local Currents.=_ Ordinary commercial zinc contains such impurities as carbon, iron, lead, etc., in small quantities. It was seen, Exp. 109, that when different metals were in contact with the zinc, the zinc was rapidly dissolved by the acid. The impurities in the zinc act like the copper plate in the simple cell, thus producing _local currents_ in the zinc, which rapidly destroy it without doing any good. These currents pass from zinc to impurities, and back to the zinc, without going out into the main wire. This local action takes place even when the main circuit is open. _=274. Reasons for Amalgamating Zinc Plates.=_ Pure zinc is not affected by dilute sulphuric acid, but it is too expensive to use in cells; so amalgamated zinc is used instead, because it is cheaper, and acts the same as pure zinc. The impurities are removed from the surface of the zinc, as the zinc alone is dissolved by the mercury. There is, then, a liquid layer of pure zinc with mercury upon the surface of the amalgamated plate. This is not acted upon by the acid when the circuit is open. A stronger and more regular current is produced with amalgamated zinc than with the impure unamalgamated zinc. =EXPERIMENT 112. To study the "single-fluid" Galvanic cell.= _Apparatus._ The galvanoscope G V (No. 58), (See § 240, etc.); the simple cell arranged as described in § 275, the zinc being amalgamated. =275. The Simple Cell= should be arranged so that the plates will be held firmly in position. The zinc, Zn (No. 60), and copper, Cu (No. 67), should be fastened to the wooden cross-piece, W C P (No. 70), as shown in Fig. 85. Care should be taken not to use longer screws than those provided for (No. 72). If the screws touch each other they will short circuit the cell. Partly fill the tumbler (No. 65) with dilute sulphuric acid (§ 258), join wires with connectors to the plates. The free ends of the wires are then ready to join to apparatus. The ends of wires _may_ be fastened under the screw-heads instead of using connectors on the plates. Do not put the plates into the acid until you read the "directions." =276. Directions.= (A) Arrange as in Fig. 86. Place the coil of G V, N and S (§ 244). _Before_ putting the plates in the acid join them to the 15-turn coil of G V (§ 242). The compass-needle should point to zero. See that the needle swings freely. (B) Place the plates in the acid, and _quickly_ bring the needle to rest with the aid of the hand, so that you can take the reading at once before the hydrogen bubbles entirely cover the copper plate. Watch the action of the needle for a few minutes. Make a note of the reading, in degrees, at the beginning of the experiment and at the end of five minutes. (See Note.) [Illustration: Fig. 85.] [Illustration: Fig. 86.] =Note.= If no change takes place in the position of the needle, the change beginning inside of 10 seconds after the plates are let down into the acid, withdraw the plates, then clean and thoroughly dry the copper to remove all traces of hydrogen. This may be done by heating the copper over a gas flame. Let the copper remain in the air 15 minutes, then try again. In taking the first reading you must work quickly. Catch the needle during its _first_ swing. If you allow it to swing back and forth until it comes to rest, your first reading will not be what it should be. (C) After the needle has remained in one position, without change, for 2 or 3 minutes, take hold of the wooden cross-piece, move the plates back and forth in the acid to dislodge the hydrogen bubbles, and note carefully the action of the needle. Does the current seem stronger when the plates are moved? Can you get the needle back to the first reading? (D) Remove the plates from the acid, dry and clean the copper, let them stand in the air for 15 minutes, then take another quick reading and compare it with the first. _=278. Polarization of Cells.=_ The acid gets a little weaker, of course, as it is decomposed by the zinc (§ 270), but the chief cause of the weakening of the current is hydrogen, which forms a filmy coating upon the copper plate. This coating even seems to soak into the copper, and it takes some time for it to be thoroughly removed. The zinc plate is kept comparatively free from hydrogen by amalgamation. _=279. Effects of Polarization.=_ The hydrogen bubbles weaken the current in at least two ways. In the _first_ place, hydrogen is not a conductor of electricity; so it holds the current back, as any other resistance would. _Secondly_, acid acts upon hydrogen as it would upon another metal. When the copper plate becomes well covered with hydrogen, the acid cannot touch it; so we really have a _hydrogen plate_ in the cell. Hydrogen acts very much like zinc in the acid; we say that it is more electro-positive than copper. The result is, then, that a new current starts up, and as this is towards the zinc, in the acid, it partially destroys or neutralizes the main zinc-to-copper current. Practical use is made of the principles of polarization (see Secondary Batteries). _=280. Remedies for Polarization; Depolarizers.=_ Any scheme by which the hydrogen may be destroyed and kept from the inactive, or negative plate, will prevent polarization. _Mechanical_ means have been employed to brush away the hydrogen by keeping up a constant circulation of the liquid. _Chemical action_ is another means by which the hydrogen may be side-tracked before it gets to the - plate in single-fluid cells. Substances like nitric acid and bichromate of potash, called _depolarizers_, contain large quantities of oxygen, and, during the chemical changes that take place, this oxygen unites with the hydrogen. These substances are used in zinc-carbon cells. (See § 286, etc. for various forms of cells.) There is another form of cell, the _two-fluid_ type, in which _electro-chemical_ means are employed, and in which a metal is deposited upon the - plate instead of hydrogen. The - plate is usually copper, copper being deposited upon it. =EXPERIMENT 113. To study the "two-fluid" Galvanic cell.= _Apparatus._ The glass tumbler, G T, (No. 65); porous cup, P C, (No. 73); the strip of zinc (No. 60), well amalgamated (§ 257), or the amalgamated zinc rod (No. 74); piece of sheet copper (No. 75), bent so that it will surround P C; copper wires, C W, with connectors; a saturated solution of copper sulphate, commonly called blue vitriol or blue stone (See § 283); dilute sulphuric acid (See § 258). With the above, set up the two-fluid cell (See § 281). The galvanoscope, G V, complete, is also needed, and if quantitative work is to be done, a pair of scales weighing to 0.1 gram is necessary. (See App. Book, Chapter I, for Home-Made Two-Fluid Cells.) [Illustration: Fig. 87.] =281. Setting Up the Two-Fluid Cell.= Fig. 87. Stand the amalgamated zinc rod, Zn, in P C, then place P C in the tumbler, G T; put in the copper plate as shown. Pour diluted acid (§ 258) into P C until it stands about 2-1/2 in. deep; then at once pour the copper solution (§ 283) into G T, on the outside of P C, until it stands at the same height as the acid _in_ P C. As soon as the liquids have soaked into P C the cell will be ready for use; but it is better to connect it with the galvanoscope at once and note the increase of current during the first few minutes while the liquids soak through P C. A crystal of copper sulphate should be put outside of P C to keep the solution full strength. This is a form of the well-known Daniell cell. Fig. 87 shows a form of home-made two-fluid cell as described in Apparatus Book. If you have the one furnished, use the rod instead of sheet zinc, and use connectors on the plates. =282. Care of Two-Fluid Cell.= This experimental cell should be taken apart when not in use. It should not be left in open circuit, even for half an hour. Even after the plates are removed, copper may be deposited upon P C in case there are any metallic impurities on it. Remove the plates and P C, and thoroughly wash them. The copper solution should be put into a bottle to prevent evaporation; the dilute acid may be thrown away to be replaced by fresh acid for the next experiment. =283. Copper Sulphate Solution= is made by adding the blue crystals to water until no more will dissolve--that is, the solution should be "saturated," extra crystals always being left in the stock bottle. An ounce of the crystals to half a tumbler of water will be about right, but a pint or so should be made at a time and be kept bottled to save time. =284. Directions.= (A) In case you have access to a pair of scales that weigh to within 0.1 gram, carefully weigh both copper and zinc before proceeding. They should be washed and dried with a cloth. See that there are no drops of mercury upon the zinc that may fall off during the experiment. (B) Replace the plates in the cell, and connect them with the 15-turn coil of G V, placed N and S. Allow the circuit to remain closed for half an hour, and record the position of the needle every 5 minutes. (C) Again wash, dry with a cloth without rubbing, and weigh both the zinc and copper. Compare the new weights with those found in (A). _=285. Chemical Action in the Two-Fluid Cell.=_ In this form of cell the hydrogen is not allowed to collect upon the copper plate. The action inside of P C is like that explained in § 270, hydrogen being set free. As soon as this hydrogen (H_{2}) comes in contact with the copper sulphate (CuSO_{4}), and it begins to do this in the walls of P C, a new chemical reaction takes place. Hydrogen has a stronger attraction for SO_{4} than Cu has, so it unites with the SO_{4}, forming H_{2}SO_{4} (sulphuric acid), and this at the same time throws out the Cu bodily. This Cu is then free, instead of hydrogen, to be deposited upon the copper plate. The current is constant, as there is no polarization. _=286. Various Galvanic Cells; Open and Closed Circuit Cells.=_ There is no one form of cell that is best for all kinds of work. If momentary currents only are wanted, such as for bells, telephones, etc., in which the cell has plenty of time to rest, _open circuit_ cells are used. These cells polarize, however, when the circuit has to be closed for any length of time. This form of cell is always ready for use, and may not need attention for months at a time. The most common forms of the open circuit cells are the _Leclanché_ (§ 287) and _dry_ cell (§ 288). Open circuit cells polarize quickly, because the depolarizer (§ 280) is slow in destroying the hydrogen. When a strong current is needed for a considerable time, such as for telegraph lines, motors, etc., a _closed circuit_ cell is necessary. The depolarization must be rapid and constant. The _bichromate_ (§ 289) and the _Daniell_ cell (§ 290) are very common forms of closed circuit cells. (See, also, Storage Cells.) =287. The Leclanché Cell= is an open circuit cell in which carbon and zinc are the plates. The carbon is surrounded with dioxide of manganese, a depolarizer; the two are either packed together in a porous cup, or the latter is compressed into blocks, which are fastened to the carbon. The porous cup stands in a jar containing a solution of sal ammoniac (ammonium chloride), which acts as the exciting fluid, and in which stands a zinc rod. The zinc is not acted upon when the circuit is open. The hydrogen given off by the decomposition of the ammonium chloride is destroyed by the oxygen contained in the manganese dioxide. The E. M. F. is nearly 1.5 volts. =288. Dry Cells= are for open circuit work. Sheet zinc forms at the same time the active plate and the outside cylinder or case. A carbon plate acts as the inactive or - plate. The exciting fluid is kept from spilling by its being absorbed by one of the various substances used for that purpose. =289. The Bichromate of Potash Cell= is a very common one for laboratory use. It gives a strong current, and although a single fluid cell, it does not readily polarize. Zinc and carbon plates are used. In the sulphuric acid, which is the exciting fluid, is dissolved bichromate of potash. This cell is used for running small motors, induction coils, etc. It has, with fresh solutions, an E. M. F. of about 2 volts. (See Apparatus Book, Chapter I., for Home-Made Batteries.) =290. The Daniell Cell=, of which the two-fluid cell used in Exp. 112 is a form, is noted for its constant current. The E. M. F. is a little over 1 volt, and it should be kept working through a resistance when not in regular use; it should not be left in open circuit. The porous cup keeps the two fluids from mixing, but it does not stop the current. =291. The Gravity Cell= is a form of the above. As one of the fluids is heavier than the other, no porous cup is needed. Gravity, together with the action of the current, tends to keep the fluids separated. A copper plate is placed in the bottom of the jar, and upon this is put the copper sulphate solution. The zinc plate is supported by the top of the jar and rests in a solution of zinc sulphate, which is lighter than the blue solution below. An insulated wire extends from the copper through the liquids. This cell is used for telegraph and similar work. (See Apparatus Book for Home-Made Gravity Cell, its Regulation, etc.) CHAPTER XVI. THE ELECTRIC CIRCUIT. =EXPERIMENT 114. To see what is meant by "divided circuits" or "shunts."= _Apparatus._ The galvanoscope, G V (No. 58); astatic galvanoscope, A G (No. 59); two-fluid cell, 2-F C (see § 281); 6 wires with connectors; small thin pieces of tin or other metal, M P, for rapidly making connections (§ 226). _Arrange_ as in Fig. 88. The wires, 1 and 4, from 2-F C, lead to the metal plates M P-A and M P-B, for convenience. The wires, 2 and 3, from G V, are also connected with these plates. The wires, 5 and 6 (dotted lines), lead from A G, to be used as directed in part (B) of the experiment. See that G V is properly placed. See that A G is adjusted. [Illustration: Fig. 88.] =292. Directions.= (A) Without A G in place, take the reading of G V. The current now passes from Cu through 1, M P-B, 2, G V, 3, M P-A, 4 to Zn. (B) Connect wires 5 and 6 to the plates, as shown by the dotted lines. Again take reading of G V, and compare it with the first reading. Does some of the current pass through A G? _=293. Divided Circuits; Shunts.=_ The current divides at M P-B into two parts; one part may be called a _shunt_ of the other. The circuit is said to be _divided_; it has two branches. If the two ends of a wire be fastened to another as in Fig. 101, the circuit is also divided. When two or more conductors lead side by side from one point to another, they are called _parallel_ circuits; that is, the conductors are joined in parallel. As strong currents would injure delicate galvanometers, a small part only of the current may be allowed to pass through the galvanometer by using a shunt. Fig. 89 shows such an arrangement, in which most of the current passes through the shunt, S. There are many practical uses of shunts. [Illustration: Fig. 89.] =EXPERIMENT 115. To see what is meant by "short circuits."= _Apparatus._ About the same as in Exp. 114, Fig. 88. The astatic galvanoscope is not needed; in place of it provide a short piece of metal, such as a battery-plate, or even a jack-knife. _Arrange_ as in Fig. 88, but without A G. =294. Directions.= (A) With the current passing as described in Exp. 114 (A), take the reading of G V. (B) Lay the ends of the metal, or other thick conductor, upon M P-A and M P-B. Compare the new reading of G V with that in part (A). (C) Remove the conductor used to short circuit G V, take the reading in degrees, then touch M P-A to M P-B; watch G V. _=295. Short Circuits=_ are very apt to occur unless care is taken. Do not allow uninsulated wires to touch each other. As shown by the above experiment, practically the whole of the current may be side-tracked by a _shunt of low resistance_. A galvanic cell is short-circuited by connecting the plates directly by a wire or other conductor. CHAPTER XVII. ELECTROMOTIVE FORCE. _=296. Electromotive Force.=_ It has been stated that a galvanic cell has the _power_ to charge one of its plates positively and the other negatively; this power is called _electromotive force_, and, for short, E. M. F. is written. The E. M. F. of a cell depends upon the kinds of plates used and their condition, the chemicals used in the exciting fluids, etc. The greater the E. M. F. of a cell the greater its power to force the current through wires, etc. The E. M. F. of a cell does not depend upon the size of its plates, as will be seen by later experiments. _=297. Unit of E. M. F.; The Volt.=_ A certain amount of E. M. F. has been taken as the standard, and, in honor of Volta, it has been called the volt. The E. M. F. of the two-fluid cell used in Exp. 113 is not far from 1 volt. If a certain cell has the power to keep up twice the difference of potential between its terminals that the Daniell cell has, we say that it has an E. M. F. of about 2 volts. _=Voltmeters=_ are instruments to measure E. M. F. =EXPERIMENT 116. To see if the E. M. F. of a cell depends upon the materials used in its construction.= _Apparatus._ Tumbler two-thirds full of dilute sulphuric acid (258); strips of zinc, Zn (No. 60); copper strips, Cu (No. 67); iron strip, I (No. 76); lead strip, L (No. 77); carbon rod (No. 64); the galvanoscope, G V (No. 58); 2 wires with connectors (§ 226), so that the plates can be changed quickly; the wooden cross-piece, W C P (No. 70). _Arrange_ as in Fig. 90. The metal strips are all of the same size; they may be held with the hand firmly against W C P, in order to have them the same distance apart in each trial. They should be lowered to the bottom of the tumbler in each case, in order to have them acted upon by the same amount of acid. Place G V properly. [Illustration: Fig. 90.] =298. Directions.= (A) With Zn and Cu connected to G V as shown (Fig. 90), take the reading in degrees, and note in which direction (east or west) the N end of the needle is deflected. Tabulate results, as shown in Fig. 91, filling in each column of your table made out on paper. (B) In like manner try the following combinations in the order given, in each case connecting the first-mentioned plate with the left-hand binding-post, L, of G V. For (B) use zinc-iron. (C) Use zinc-lead; (D) iron-copper; (E) iron-lead; (F) lead-copper; (G) copper-carbon. [Illustration: +------+---------------+------------+-------------+------------+ | PART | PLATES. | LIQUID. | DEFLECTION. | CURRENT IN | | | | | | CELL FROM | +------+-------+-------+------------+-------------+------------+ | (A) | ZINC. |COPPER.| DIL. SULP. | 65° WEST. | CU TO ZN | | | | | ACID. | | | | (B) | | | | | | | | | | | | | | (C) | | | | | | Fig. 91.] =299. Note.= Some of the combinations produce but slight currents. In case G V is not delicate enough to show clearly which way the current passes, use the astatic galvanoscope in its place for such combinations. _=300. Discussion.=_ Exp. 116 clearly showed that different combinations of metals in the acid have different powers of pushing electricity through the galvanoscope. Although some of the pairs of metals furnished so weak a current that it was necessary to use the astatic galvanoscope to study the current, all produced _some_ current, and from the results can be formed an electromotive series (§ 301). The strength of acid, condition of plates, etc., affect the E. M. F. of a cell. =301. Electromotive Series.= All metals are not acted upon to the same degree by dilute acid. From the results of Exp. 116 it is seen, part (B), that iron is electronegative to zinc; that is, the current in the cell flows from zinc to iron. Part (D) showed that iron is electropositive to copper, as the current flowed from iron to copper in the cell. It is possible to arrange the metals in a series, one below the other, in such a way that any one will be electronegative to those above it and electropositive to those below it; that is, the list should have the most electropositive metal at the top, and the one least acted upon by the acid at the bottom. Make such a list from your results. The farther the metals used are apart in the _list_, the greater will be the E. M. F. of the cell. Good carbon is acted upon the least of all, so zinc and carbon are better than zinc and copper. =EXPERIMENT 117. To see whether the electromotive force of a cell depends upon its size.= _Apparatus._ Galvanoscope; two glass tumblers; dilute acid; two wooden cross-pieces; two copper and two zinc strips, the same size as those used for Exp. 112. (See § 275). These materials will form two simple cells like Fig. 85. Have about 3 in. of acid in one tumbler, and but 1 in. in the other. The plates of one cell will then be about 2-1/2 in. in acid, and those of the other cell only 1/2 in. in acid. This gives us the same effect as a large and a small cell. =302. Directions.= (A) Join the large and small cells with G V so that their currents will oppose each other. To do this, join the two zinc plates by means of a wire and connectors. With two other wires connect the two copper plates with the galvanoscope binding-posts, and watch for any indication of current. Does one cell oppose the other? _=303. Discussion.=_ The E. M. F. of a cell, then, does not depend upon the size of its plates. The small piece of zinc--that is, the one in but little acid--had the same potential as the large piece; they must have had, as they were joined. The large cell will give a stronger current, under certain conditions, than the small one; but this depends upon other things than E. M. F. (See experiments under Current Strength.) A zinc-copper cell, like the one just used (Exp. 117), has the same _voltage_ as one of the same kind would have, even though it were made as large as a barrel. CHAPTER XVIII. ELECTRICAL RESISTANCE. _=305. Resistance.=_ It is harder for a horse to draw a wagon through deep sand than over a smooth pavement. We may say that the sand holds the horse back--that is, it offers a resistance. The electric current does not pass through all sorts of substances with the same ease, and when it succeeds in pushing its way through a circuit of considerable resistance, we cannot expect it to arrive at the end of its journey without being weaker than when it started. Do we expect this of a man or horse? We shall soon see that there is a definite relation between resistance and the strength of the current at the end of its journey. =EXPERIMENT 118. To study the general effect of "resistance" upon a current.= _Apparatus._ Galvanoscope, G V (No. 58); resistance coil, R C (No. 79) (§ 310); two-fluid cell, 2-F C (§ 281); 4 wires with connectors (§ 226). _Arrange_ as in Fig. 92. The current passes as shown by the arrow, and the circuit may be opened and closed at the metal plate, M P, or by using a key in its place. Properly place G V. =306. Directions.= (A) Take the reading of G V in degrees, the current passing through the entire length of R C. (See § 310.) (B) Change the end of wire 4 from binding-post R to M, on R C, so that the current will pass through one-half only of R C. Note the reading of G V. (C) Remove R C entirely and connect wires 3 and 4 by means of a metal plate. Compare the readings of (A), (B) and (C). What do they show? [Illustration: Fig. 92.] _=307. External Resistance; Internal Resistance.=_ When we consider a circuit like that shown in Fig. 92 we see that it is composed of two parts, and that we have two kinds of resistances. The wires, instruments, etc., make up what is called the _external resistance_ of the circuit; that is, the part that is external to the cell. The liquids in the cell offer a resistance to the current; this is called _internal resistance_. (See § 314.) The strength of the current depends upon the relation between these two resistances, as will be seen by future experiments, as well as upon the E. M. F. of the cell. As liquids are not as good conductors as metals, the internal resistance of cells may be quite high. _=308. Unit of Resistance; The Ohm.=_ Whenever anything is to be measured, a standard, or unit, is necessary. The unit of resistance is called the ohm, in honor of Ohm, who made careful investigations upon this subject. A column of mercury having a length of a little over 3 feet has been taken as a unit. (The column taken is 106.3 cm. with a weight of 14.4521 grams; it has a cross-section of about 1 sq. mm., at a temperature of 0°C.) Mercury is a liquid, and has no "grain" to affect the resistance. For the use of students, 9 ft. 9 in. of No. 30 copper wire, or 39 ft. 1 in. of No. 24 copper wire will make a fairly good ohm. We might, of course, take any other length as _our_ standard; the above, however, will give results that are approximately correct. (See wire tables at the end of this book.) _=309. Resistance Coils; Resistance Boxes.=_ Coils of wire, having carefully-measured resistances, are called _resistance coils_. The wire for any coil is doubled at the center before it is wound into coils or upon spools (Fig. 93) to avoid the magnetic effect. The ends of the coils are attached to binding-posts, or to brass blocks, in regular instruments, so that one or more coils can be used at a time; that is, so that they may be handled in a manner similar to that in which the different coils on the galvanoscope are used. If we have 4 coils of 1, 2, 2, and 5 ohms resistance, we shall be able to use any number of ohms from 1 to 10 by making the proper connections. (See Apparatus Book, chapter XVII, for Home-made Resistance Coils.) For protection and convenience, coils are usually placed in a box, the whole being called a _resistance box_. The ends of the coils are joined to brass blocks, placed near each other on the top of the box, and between which may be pressed plugs when it is desired to short circuit the coils. By removing a plug, the coil, whose ends are joined to the blocks touching it, is brought into the circuit. [Illustration: Fig. 93.] [Illustration: Fig. 94.] =310. Simple Resistance Coil.= Fig. 94 shows a simple form of coil, R C (No. 79). The total resistance is 2 ohms, L (left) and R (right) being binding-posts to which the ends of the coil, C, are joined. M (middle) connects with the middle of the wire, at which point the wire is doubled. The coil is fastened to a stiff pasteboard base, B. =Connections.= When 2 ohms resistance are wanted, let the current enter at L and leave at R (or the reverse). When 1 ohm is wanted, let the current leave or enter at M, the other wire being joined to L or to R. Connections should be made with spring connectors. See § 229. =EXPERIMENT 119. To test the power of various substances to conduct galvanic electricity.= _Apparatus._ Galvanoscope, G V (No. 58); dry cell, D C, or two-fluid cell, 2-F C; pieces of different metals; wood, dry and damp; tumbler of pure water; rubber; ebonite; silk; glass, etc., etc. _Arrange_ as in Fig. 92, leaving out R C, and instead of having M P between wires 1 and 2, use their free ends to press firmly upon the ends of the substance to be tested; that is, the body under test should take the place of M P in the Fig. G V will show a deflection, of course, when the particular thing under test is a conductor. =311. Directions.= (A) Make tests with the above substances, and with any others at hand, and note which are conductors and which are not. _=312. Conductors and Nonconductors.=_ It is evident, from the experiments, that bodies which conduct static electricity do not necessarily conduct galvanic electricity. The greater the E. M. F. of a current, the greater its power to overcome resistance. Some bodies, like dry wood, that readily conduct the high potential static electricity, make fairly good insulators for the low potential galvanic currents. For convenience, substances may be divided into _good conductors_, _partial conductors_, and _insulators_, or nonconductors. _=Good Conductors.=_ Metals, charcoal, graphite, acids, etc. _=Partial Conductors.=_ Dry wood, paper, cotton, etc. _=Insulators.=_ Oils, porcelain, silk, resin, shellac, ebonite, paraffine, glass, dry air. [Illustration: Fig. 95.] =EXPERIMENT 120. To find the effect of sulphuric acid upon the conductivity of water.= _Apparatus._ Galvanoscope, G V; cell; 2-F C; connecting wires; saucer or tumbler, S; a little sulphuric acid. _Arrange_ as in Fig. 95. =313. Directions.= (A) Put a little pure water in S, and see if enough current can pass through it to deflect the needle of G V. The ends of the wires, 1 and 2, should be gradually moved toward each other, the needle being watched. (B) Put 4 or 5 drops of concentrated acid into the water; stir it, then repeat the test. What effect has the acid? _=314. Internal Resistance.=_ As found in Exp. 120, pure water is not a good conductor of galvanic electricity. The acid in the simple cell, and in other single-fluid cells, acts upon the zinc and at the same time makes it possible for the current to pass, as it reduces the internal resistance. As seen later, this resistance in cells is greatly diminished by bringing the plates near each other, and by increasing the surface of the plates that are in contact with the acid. The larger the plates the less the internal resistance, other things remaining the same. The internal resistance of a _battery_ can be changed by connecting the cells differently. (See Chap. on Arrangement of Cells.) [Illustration: Fig. 96.] =EXPERIMENT 121. To find what effect the length of a wire has upon its electrical resistance.= _Apparatus._ A No. 30 German-silver wire, G-S W, a little over two meters long, un-insulated (No. 81); the two-fluid cell, 2-F C (Exp. 113); galvanoscope, G V (No. 58); plate binding-posts, X, Y and Z (No. 83-84-85); copper washers (No. 87). _Arrange_ as in Fig. 96, so that the current will flow, at first, as shown by the arrow. The metal plates, M P 1 and M P 2, are used so that the connections may be changed without disturbing G V. The binding-posts may be fastened directly to the top of the table; but it will be more convenient to permanently fix them to a board, B, as shown, so that the same arrangement can be used for future experiments. The binding-posts, X and Y, should be about 1/8 in. apart, just far enough so that their edges do not touch each other. The binding-post, Z, should be fastened to B with its inside end 1 meter(100 centimeters, cm.) from the ends of X and Y. Marks should be made upon B, 10 centimeters apart, as indicated by the cross lines. This distance may be taken from the scale on the rule (No. 88). Fasten one end of the No. 30 wire, G-S W, to X. To do this twist its end around the screw, S, between X and the copper washer, then turn the screw in with a screw-driver until it firmly holds X to the board. Pass the wire around the screw in Z, and bring its free end to the other binding-post, Y, to be fastened (Fig. 96). Two meters of wire then form a path for the current from X to Y. Have the board wide enough so that another set of binding-posts can be put by the side of Y. It will be best to permanently leave the No. 30 wire upon the board, and to fasten the No. 28 wire (next experiment) to another set of binding-posts, placed in the same manner as those in Fig. 96. Make holes in the wood with an awl before forcing in the screws. =315. Note.= This experiment is usually done with a reverser in the circuit, first taking readings with the current passing in one direction, and then in the opposite direction. Considerable time will be saved by taking all the readings for one direction of the current at a time, simply using different lengths of German-silver wire, and allowing the current to flow constantly during each part. This obviates all danger of poor contacts in the reverser, etc.; it saves the trouble of handling the reverser, and much of the time needed for the needle to come to rest. [Illustration: +--------------------+----+----+----+---+---+---+---+---+----+---+ |LENGTH OF CIRC., CM.|200 |180 |160 |140|120|100| 80| 60|200 | O | +--------------------+----+----+----+---+---+---+---+---+----+---+ |DEFLECTION; WEST |26° |28° | 30°| | | | | | 26°|67°| +--------------------+----+----+----+---+---+---+---+---+----+---+ |DEFLECTION; EAST |25° |27° | 30°| | | | | | 25°|67°| +--------------------+----+----+----+---+---+---+---+---+----+---+ | AVERAGE |25.5|27.5| 30 | | | | | |25.5|67 | +--------------------+----+----+----+---+---+---+---+---+----+---+ Fig. 97.] =316. Directions.= (A) With the circuit arranged as in Fig. 96, and with G V properly placed, take the reading of G V, the current passing through 200 cm. of No. 30 G-S W. Record your results in a diagram made like Fig. 97. The row of figures across the top shows the length of the circuit. The table is started with results from one experiment. Your results will probably be different from these. (B) Get the deflection with the current passing through 180 cm. of wire. To do this press a piece of copper (O, Fig. 96) upon the wire at the mark 10 cm. from Z, another thin piece of metal, U, having been slipped under the wire. This will allow the current to pass across from one wire to the other. Record the deflection in the col. marked 180. (C) Record the deflections for the lengths, 160 cm., 140, 120, 100, 80, and 60; then repeat (A) to be sure that the cell has been working uniformly. This deflection should agree with that in (A). (D) Change the direction of the current through G V; to do this, change wire, 1, from M P 2 to M P 1, and wire 5 to M P 2. This must be done without disturbing G V. (E) Repeat (A), (B), and (C), and record the deflections for the different lengths. (F) Get the average deflections. (G) Take, for future use, the deflection produced without G-S W being in the circuit. Swing the end of wire, 3, that is joined to Y, around to M P 2. The current will then pass simply through G V. Record deflection in col. marked O. =Note.= It is best to do the next experiment at once with the same cell, so that the results of the two experiments can be compared. In case this is impossible, get your cell to produce the same deflection when you use it again, as shown in col. O, Fig. 97. You can regulate the deflection of the needle of G V by varying the strength and quantity of the acid in P C. _=317. Discussion.=_ The resistance of a wire evidently depends (Exp. 121) upon its length. The _exact_ relation between resistance and length cannot be seen from these results, however, which are used in the next experiment. It will be shown later that in a wire, other things remaining the same, the resistance varies directly as its length. =EXPERIMENT 122. To find what effect the size (area of cross-section) of a wire has upon its electrical resistance.= _Apparatus._ Same as in last experiment, with one change, however. Replace the No. 30 G-silver wire with a No. 28 G-silver wire (No. 82), or, what is better still, fasten it to another set of binding-posts on the board and leave the No. 30 for future use. The two should be stretched side by side for constant use. =318. Directions.= (A) See that your cell is in the same condition as for Exp. 121; that is, it should produce the same deflection of the needle of G V as before, when the two, only, are in the circuit. (See Exp. 121, G.) The deflection may be changed by changing the strength and quantity of the dilute acid and copper solution. (B) Find the average deflection of the needle with the 2 meters of No. 28 G-s wire in the circuit, arranged as in Fig. 96. (C) Compare this average deflection with the results obtained in Exp. 121, in order to find what length of the No. 30 wire has the same resistance as 2 meters of No. 28 wire. To find how many times greater one length is than another, we divide the larger length by the smaller; hence, to find the relation between the two lengths of wire that gave the same deflection,--lengths of equal resistance,--we divide the 200 centimeters (the length of the No. 28) by the length of No. 30 found as directed. (D) From the wire tables it will be found that the area of cross-section of No. 28 wire is about 1.59 times that of No. 30 wire. How does this quotient, or ratio, compare with that found in part (C)? What is the relation between the area of cross-section of a wire and its resistance? (See § 319, also Exp. 136.) _=319. Discussion.=_ If we find that a certain wire, X, which is 576 feet long, has the same resistance as a shorter one, Y, 360 feet long, we see (576 divided by 360) that the ratio of their lengths is 1.6. This means that the longer one, X, is 1.6 times as good a _conductor_ as Y; or, in other words, that the _resistance_ of Y is 1.6 times that of X. It is easier for water to flow through a large pipe than it is through a small one. The same general principle is true of electricity. A large wire offers less resistance to the current than a small one of the same material. If one wire is twice the size of another of equal length, it will be twice as good a conductor as the other; that is, it will have one-half the resistance of the smaller, provided they are of the same material. (See Laws.) =EXPERIMENT 123. To compare the resistance of a divided circuit with the resistance of one of its branches.= _Apparatus._ Same as in last experiment. Arrange as in Fig. 98. =320. Directions.= (A) Note the deflection of the needle when the current passes through 1 meter of G-s wire, as shown. This will be considered as one branch of the divided circuit. (B) Still allowing the current to pass as in part (A), press a piece of copper firmly across the binding-posts X and Y, to electrically connect them, and note the reading of the needle. In this case the current divides at Z through the two branches. What is learned from the results of (A) and (B)? (C) See if you can show the same results with apparatus arranged as in Fig. 99. [Illustration: Fig. 98.] [Illustration: Fig. 99.] _=321. Discussion.=_ Two wires placed side by side as in (B), Exp. 123, really form a conductor having twice the size (area of cross section) of one of the branches. The more paths a current has in going from one place to another, the less the resistance. (See Exp. 135.) The wires are said to be in "parallel" or in "multiple arc." [Illustration: Fig. 100.] [Illustration: Fig. 101.] =EXPERIMENT 124. To study the effect of decreasing the resistance in one branch of a divided circuit.= _Apparatus._ Galvanoscope, G V (No. 58); resistance coil, R C (No. 79); two-fluid cell, 2-F C (§ 281), or a dry cell; 6 connecting wires; metal plates, M P. _Arrange_ as in Fig. 100, so that the current divides into two branches at M P 1. The branches unite at M P 2. =322. Directions.= (A) Take the reading of G V with 2 ohms resistance in the lower branch; that is, with the whole of R C in circuit. (B) Take the reading of G V with one ohm in circuit; that is, with the end of wire, 5, connected to M instead of to R. (C) Cut out R C from the lower branch by replacing it with a metal plate, thus joining wires 3 and 5. Compare the results from (A), (B), and (C), and explain. _=323. Current in Divided Circuits.=_ Let us consider a circuit like that shown in Fig. 101. If the points, C and Z, were at the same potential, no current would pass from C to Z. As the current does pass, Z must be at a lower potential than C; there is a _fall of potential_ from C to Z. If the branch, A B, has the same resistance as R X, the same amount of current will pass through each. Exp. 124 has shown that when the branches have unequal resistances, most of the current passes through the one of small resistance. If R X has a greater resistance than A B, most of the current will pass through A B. CHAPTER XIX. MEASUREMENT OF RESISTANCE. [Illustration: Fig. 102.] =EXPERIMENT 125. To study the construction and use of a simple "Wheatstone's Bridge."= _Apparatus._ Fig. 102. A Wheatstone's bridge, W B (No. 80), (§ 324); astatic galvanoscope, A G (No. 59); dry cell, D C (No. 51); key, K (No. 55); 7 wires with spring connectors, two of which, R and X, are equal in length; metal plate, M P, for connecting wires. _Arrange_ as in Fig. 102. The carbon of D C is joined to K, and this to the point, C, of the bridge. The zinc of D C connects with the point Z on W B. The A G is placed between the branches for clearness. Wire 3 is joined to the left-hand binding-post of A G, and wire 4 joins M P with the right-hand one. When the end of wire 3 does not touch G-s W, it is evident that as soon as K is pressed, the current divides at C on its way to Z, where the branches unite again. K is used so that D C will not be polarized by steady use. [Illustration: Fig. 103.] =324. The Simple Wheatstone's Bridge= (Fig. 103) consists of a wooden base, W, at the ends of which are fastened two aluminum conductors, 1 and 3. At one side of W is fastened another conductor, 2. In Fig. 104 are side views of the conductors. These are used merely for convenience in making connections, and take the place of the metal plates used in previous experiments. A German-silver wire, G-s W, is stretched between 1 and 3, and under this is a scale, S, divided into 100 small parts, these being tenths of the larger divisions. The ends of G-s W are held between eyelets, as shown at E, Fig. 104. [Illustration: Fig. 104.] =Reading the Scale.= The value of part A can be read directly from the scale, using the lower row of figures. The point marked P, for example, would be read 3.7 (three and seven-tenths large divisions); B would be 6.3, found by subtracting 3.7 from 10. The sum of A and B must always equal 10. The 6.3 may also be read directly by using the upper row of figures for the whole numbers, counting the tenths to the left. Try to divide the smallest divisions into halves, at least; that is, if A = 3.75, B = 6.25. Take the readings carefully. =325. Directions.= (A) Touch the free end of wire, 3, to the point, C, which has a higher potential than M P. Press down K for an instant only. Some current should pass through A G, as a shunt. Should it pass from C to M P or the reverse? Note in which direction the right-hand end of the astatic needle is deflected. (B) Swing the end of 3 around and touch it to the point, Z, which has a lower potential than M P. Press K for an instant, watch the needle, and compare with the results in (A). (C) Move the free end of 3 along on G-s W, touching K at intervals, until a point is found at which the needle of A G is not deflected. How does the potential of this point compare with that of M P? _=326. Discussion; Equipotential Points.=_ Since one end of the G-s W has a higher, and its other end has a lower potential than M P, there must be, somewhere on it, a point at which the potential is the same as at M P. This place is quickly found by sliding the free end of wire, 3, along, pressing K occasionally, until A G shows that no current tends to pass through it in either direction, when the current passes from C to Z through the two branches of the divided circuit. This point and M P are called _equipotential points_. If the resistance of the part, X, be increased, it should be evident that the part of the bridge-wire, B, should be also increased to find a point having the same potential as M P; that is, the end of 3 should be moved towards C. We have, in the bridge-wire, a simple means of varying the resistance of its parts, A and B. =327. Use of Wheatstone's Bridge.= It will be found, upon trial, if we put a resistance of 2 ohms in place of R, Fig. 102, and 2 ohms in place of X, that the free end of wire 3 will have to be at the center of the bridge-wire in order to get a "balance"; that is, to find the place where A G is not affected. No matter what the resistance of R and X are, provided they are equal, this will be true. The value of both A and B, on the scale, will be 5 whole spaces, no tenths. From this we see that A: B:: R: X, which reads A _is to_ B _as_ R _is to_ X; this means that A × X = B × R. Supplying the values of the letters, we have 5 × 2 = 5 × 2. If we did not know the value of X, that is, if we were measuring the resistance of a coil of wire, using a 2-ohm coil as the standard, or R, we could find the value of X, knowing the other 3 parts of the proportion. 5 × X = 5 × 2, which means that 5 times the value of X is 10; hence the value of X is 10 ÷ 5 = 2 ohms. Suppose that we have R = 2 ohms, which is the standard resistance coil (No. 79), and are trying to find the resistance of a coil, X. We slide the end of wire, 3, along on the bridge-wire until the correct place is found. (See Exp. 125, 126, for details.) Take the values of A and B (§ 324), supply them in the equation given, and work out the value of X. =328. EXAMPLE.= R = 2 ohms; A = 3.7; B = 6.3; to find the value of X in ohms. A: B:: R: X, which means that A × X = B × R, or 3.7 × X = 6.3 × 2. X must equal, then (6.3 × 2) ÷ 3.7 = 3.405 ohms. =Note.= In practice it is most convenient to make connections as shown in Fig. 105 when measuring resistances (Exp. 126). The arrangement given in Fig. 102 is simply for explanation. It will be seen that the smaller A is, compared with B, the larger the unknown resistance compared with your standard. [Illustration: Fig. 105.] =EXPERIMENT 126. To measure the resistance of a wire by means of Wheatstone's Bridge; the "bridge method."= _Apparatus._ Same as in Exp. 125; the two-ohm resistance coil, R C (No. 79); a coil of wire, X, as, for example, the 15-turn coil on the galvanoscope, G V (No. 58). _Arrange_ as in Fig. 105. You will observe that the central conductor of the bridge (2, Fig. 104) takes the place of M P in previous explanations. We still have the same kind of a divided circuit as explained in Exp. 125, A G being connected with points of equal potential. It will be found convenient to have D C at the right, and A G facing you at the left, the key being in front. (See Exp. 107 in regard to adjusting A G.) Notice that you have a standard resistance (2 ohms) in place of R, Fig. 102, and an unknown resistance (galvanoscope coil) in place of X. (See § 330.) =329. Directions.= (A) Touch the free end of wire, 3, to the left-hand side of the bridge-wire, press the key for an instant, only, and note the direction taken by the right-hand end of the needle. Move the end of wire, 3, to the right-hand side of the bridge-wire, touch key, watching needle. Does the needle move more or less than before? In the same or opposite direction? If the deflections are opposite, the point that has the same potential as binding-post, 2, must be _between_ the two points touched. (B) Be sure that all connections are good. Find the point on G-s W, at which there is no deflection, as directed in Exp. 125 (C). Note the readings on the scale, as explained in § 324. (C) Make the proper calculation, § 327, 328, and find the resistance of the coil of G V, the resistances of the wires joining R C and G V to the bridge being neglected. (D) Make proper allowances for the resistances of the wires just mentioned (see § 330), and compare them with the results found in part (C). =330. Allowances for connections.= It should be remembered that the wires joining R C and G V to the bridge also have some resistance. Such connections, in regular instruments, are made by heavy copper straps or by thick, short wires, so that their resistances can be neglected. In case you use the ordinary No. 24 copper wire, as directed, the resistances of the pieces can be measured by means of the bridge, or you can calculate their resistances from the wire tables. The resistances should be allowed for. It is evident that your standard resistance is 2 ohms _plus_ the resistance of the connecting wires, and that the resistance of the coil, X, is found by deducting the resistance of its connecting wires from that found from the proportion previously used. _Example._ We see from the table that the resistance of about 39 ft. 1 in. of No. 24, B and S copper wire is 1 ohm. This equals 469 in. If 469 in. have a R (resistance) of 1 ohm, 1 in. will have a R of one-469th of an ohm; that is 1 divided by 469, which equals a little over .002 ohm. For every inch of No. 24 wire used, then, for connections, we may allow .002 ohm. This will be near enough for our purposes. Suppose that each connection is 18 in. long, the regular wires with connectors being used. The R of the 36 in. joined to R C will then be 36 times .002 = .072 ohm. Our standard R must then be considered as 2.072 ohm. If we substitute this in the example, as stated in § 328, we have 3.7 × X = 6.3 × 2.072. X must equal (6.3 × 2.072)/3.7 = 3.528 ohm, which includes the unknown resistance and 36 in. of connections, the R of which is .002 ohm; 3.528 - .072 = 3.456, the resistance of X alone. Compare this with the answer to example, § 328. Make allowances according to length of connectors used. _=Note.=_--Carefully keep all the results of these experiments in a note book for future reference. Be sure that connections are good. =EXPERIMENTS 127-137. To measure the resistances of various wires, coils, etc., by the "bridge method."= _Apparatus._ The coils of wire, etc., as stated in the "Directions" of each experiment. The details of each piece of apparatus may be found by referring, from the numbers given, to the "Apparatus List," and to descriptions in the paragraphs mentioned. Also all the apparatus of Exp. 126. =Note.= Make proper allowances for connections (§ 330) in all experiments in measuring resistances. =EXPERIMENT 127.= =331. Directions.= (A) As explained in Exp. 126, measure the resistance of the 10-turn coil of G V, allowing for connections (§ 330). Read the bridge-scale carefully. (B) Use one-half of the 2-ohm coil as standard and repeat. =EXPERIMENT 128.= =332. Directions.= (A) Measure the resistance of the 5-turn coil of G V (see Exp. 126, etc.), using 2 ohms as standard. (B) Use 1 ohm as standard, repeat, and compare results. (C) Add the resistances of the 5 and 10-turn coils, and compare the sum with the resistance of the 15-turn coil, as found in Exp. 126, D. The difference should be but a few hundredths of an ohm. =EXPERIMENT 129.= =333. Directions.= (A) Measure the resistance of the coil of No. 24 copper wire (No. 89). This coil is used for later experiments. Spring connectors are fastened to the ends of this coil, allowing it to be directly connected to the conductor on the bridge, so no allowance should be made for its connecting wires. (See Exp. 126 for details.) Mark the resistance upon the coil for future use. (See Note.) =Note.= The student will be surprised, perhaps, to find that different results are obtained for the resistance of a given wire in case he uses different standard resistances in the various tests; that is, he will probably get a different result in Exp. 127 (A) from the result of Exp. 127 (B). The difference here, however, may not be large. The best results are obtained by making the standard resistance as nearly equal as possible to the resistance to be measured, so that a balance can be found when the end of wire 3 (Fig. 105) is near the center of the bridge-wire. If R, Fig. 105, is much larger or smaller than X, the point desired on G-s W will be near one of its ends, and large errors thereby produced. The approximate resistance of X can be found by trial, then more or less resistance can be used for R to suit. The student should make several coils as explained in Apparatus Book, Chapter XVII. The resistance of the different coils furnished should be measured and marked. These can be used to vary the value of R. =EXPERIMENT 130.= =334. Directions.= (A) Measure the resistance of the coil of No. 25 copper wire (No. 90). (See Exp. 126 for details and the Note, Exp. 129.) =EXPERIMENT 131.= =335. Directions.= (A) Measure the combined resistance of the two coils used in Exps. 129 and 130, when they are joined in "series"; that is, when one end of one coil is joined to one end of the other by means of a metal plate, the free ends being connected to the bridge (Exp. 126). The current has to travel through the entire length of both coils. (B) Compare this result with the sum of their separate resistances found in Exps. 129 and 130. (See Exp. 129, Note.) =EXPERIMENT 132.= =336. Directions.= (A) Measure the resistance of the two coils (Exp. 131) when they are joined "in parallel." (See § 293.) They may be joined in parallel by connecting them both to the bridge at the same time, one end of each being slipped onto 2 (Fig. 103), the other end of each being joined to 3. In this way the current has two paths, side-by-side, to get from 2 to 3. (See Exp. 129, Note.) (B) Compare this resistance with that of Exp. 131. =EXPERIMENT 133.= =337. Directions.= (A) Measure the resistance of 1 meter of No. 28 German-silver wire. Use the wire as arranged on a board, Exp. 122 (Figs. 96 and 98), making the connections with the bridge from binding-posts, X and Z. (See Exp. 129, Note.) The wires connecting the bridge with the ends of the G-s wire will each have to be about 2 ft. long. In making deductions (§ 330) figure according to the length used. (B) Divide the total resistance by 100 to get the resistance of 1 cm. of the wire, and carefully mark off the board into cm. This will give 100 parts between X and Z. =EXPERIMENT 134.= =338. Directions.= (A) Using the No. 28 G-s wire on the board, as arranged for Exp. 122, measure the resistance of the 2 meters in series, the connections being made with the bridge from X and Y, Fig. 98. (B) Compare the result with that of Exp. 133. What is the relation between the length of a wire and its resistance? See Summary of Laws. (See Exp. 129, Note.) =EXPERIMENT 135.= =339. Directions.= (A) Measure the resistance of the above two meters of No. 28 G-s wire when joined in parallel. (§ 293.) The binding-posts, X and Y, can be joined by a short wire with connectors on its ends, or by clamping a thin strip across by means of spring connectors. Use the 2-ohm coil as the standard, and make proper allowances. (§ 330.) (B) From the results of Exps. 132 and 135 what can be said about the resistances of parallel circuits as compared with the resistances of the separate branches? =EXPERIMENT 136.= =340. Directions.= (A) Arrange the 2 meters of No. 30 G-s wire on the table or board, again (Exp. 121, Fig. 96). (B) Measure the resistance of one meter. Find the value of X approximately, and use a resistance for R that will suit. (See Exp. 129, Note.) (C) Divide the result by 100 to get the resistance of 1 cm. of the wire. (D) Compare the resistance of one meter of No. 28 G-s wire, found in Exp. 133, with the resistance of 1 meter of No. 30 G-s wire. What is the relation, then, between the size (area of cross-section) of a wire and its resistance? (See the results of Exp. 122, and § 319, also Summary of Laws.) =EXPERIMENT 137.= =341. Directions.= (A) Measure the resistance of 2 meters of No. 30 copper wire, arranged on a board as in Fig. 96. (See Exp. 129, Note.) Get the resistance of 1 meter. (B) Compare the conductivities of copper and German silver by studying the results of Exps. 136 and 137. Which has the greater resistance? To find out how many times greater one resistance is than the other, divide the larger by the smaller. =EXPERIMENT 138. To study the effect of heat upon the resistance of metals.= _Apparatus._ Same as for Exp. 126; the coil of No. 24 wire (No. 89); a lamp or other source of heat. Arrange as in Fig. 105. =342. Directions.= (A) Measure the resistance of the coil as before, Exp. 129. The result should nearly agree with that of Exp. 129, provided connections, etc., are the same. (B) Remove the coil from the bridge, hold it about a foot above a lamp or stove, to warm it thoroughly, but do not heat it enough to injure the covering. It will take a minute or so to warm it so that the heat will get to the inside also. (C) Replace the coil, measure its resistance, and compare the result with its resistance when cold. Does heat increase or decrease the resistance of a copper wire? _=343. Effect of Heat upon Resistance.=_ Although there was but the fraction of an ohm difference in the resistances of the hot and cold coil, it was evident that changes of temperature affect the conducting power of copper. This is true of all metals; but German silver and other alloys are much less affected than pure metals, so they are used in making standard resistance coils. The resistance of liquids that can be decomposed by the electric current decreases as the temperature rises. Carbon acts like the liquids, while the resistance of metals _increases_ as their temperature rises. =EXPERIMENT 139. To measure the resistance of a wire by the method of "substitution."= _Apparatus._ The coil of No. 24 wire (No. 89), the resistance of which has been measured, but which will be considered an unknown resistance, X; G V, 2-F C, M P, connecting wires, etc., previously used; rheostat (§ 344). Arrange as in Fig. 106 first, then as in Fig. 107. _=344. Simple Rheostat.=_ The No. 28 and No. 30 G-s wires stretched upon the board (Fig. 96), make a convenient form of rheostat. The resistance per cm. being known from the results of Exp. 133 and 136, the resistance for any number of cm. is easily found. The 10-cm. divisions should be divided into centimeters. These spaces may be marked off from the rule (No. 88). [Illustration: Fig. 106.] =345. Directions.= (A) Be sure that 2-F C gives a constant current, shown by the uniform deflection at G V, when arranged as in Fig. 106. Do not use a cell that quickly polarizes. The coil, X, forms a part of the circuit; it is joined to wires, 1 and 2, by means of metal plates, so that it may be quickly removed without disturbing either G V or 2-F C. Carefully read the deflection at G V. (B) Remove X from the circuit, and join the free end of wire, 2, to binding-post, X, and the free end of wire, 1, to a small piece of sheet copper, which can be firmly pressed upon the G-s wire to make a contact. Move this along on the G-s wire until the deflection produced equals that of part (A), remembering that the longer the G-s wire in the circuit the less the deflection. Make two or three trials, as one or two cm. difference in length make but a little difference in the deflection. Note the number of cm. of G-s wire used, the resistance of which must equal that of the coil, X. (C) Find the resistance of X by multiplying the length just found by the resistance of each cm., and compare the result with the value found by using the bridge method directly. [Illustration: Fig. 107.] =EXPERIMENT 140. To measure the E. M. F. of a cell by comparison with the two-fluid cell.= _Apparatus._ Rheostat (§ 344); the two-fluid cell, 2-F C (Exp. 113), the E. M. F. of which may be taken as 1 volt; dry cell, D C; galvanoscope, G V. Arrange first as in Fig. 107. =346. Directions.= (A) Be sure that 2-F C gives a constant current. Take the reading of G V without the rheostat in the circuit; that is, with wires, 2 and 1, joined directly. The deflection should be 50 or 60 degrees at least, and be constant. (B) Attach a small piece of copper to the end of 1, and firmly rub it along upon the G-s wire, thus introducing resistance into the circuit, until the deflection is, say, 60° (50 or 55 degrees will do). Note the length of G-s wire used and call it (B). (C) Gradually add more resistance by moving the end of 1 along until the deflection is 50°, 10 degrees less than before. (If the original was 50° make the new 40°). Call the number of cm. of wire used (C). (D) Replace 2-F C with the dry cell D C. Add resistance, as before, until G V indicates a deflection of 60°, being careful not to keep the circuit closed long enough to partially polarize D C. Make 2 or 3 trials, allowing D C to rest a few minutes between each. Call the number of cm. of G-s wire used (D). (E) Again add more resistance, as in (C), until the deflection is reduced to 50°. Call the length used (E). =347. Calculation.= It is known that resistances that are able to reduce the strength of the currents equally are proportional to the electromotive forces; that is, the electromotive forces of the two cells are to each other as the two resistances necessary to produce equal changes in the deflections, which, of course, indicate equal changes in the strength of the currents. Since the resistances used in the two cases are directly proportional to the lengths used, we have: Length (C-B): Length (E-D):: E. M. F. of 2-F C: E. M. F. of D C. Substitute the values found and find the E. M. F. of D C. =EXPERIMENT 141. To measure the internal resistance of a cell by the "method of opposition."= _Apparatus._ All the apparatus of Exp. 126. Two simple cells (§ 275), the plates of which should be of the same size, the same distance apart, and immersed in acid to the same extent in both. The acid in both should be of the same strength. =348. Directions.= (A) Connect the two cells in opposition, so that no current will be generated by them, and so that the two can be treated as a dead resistance. Do this by joining the two zinc plates by a wire with connectors, and use wires to connect the copper plates to the bridge like any other unknown resistance. (B) Measure the resistance of the two by the regular bridge method, allowing for wires used for connections. One-half of the resistance found will give the internal resistance of one cell. (See Note.) =Note.=--The standard resistance will have to be arranged to suit each particular case to make the calculations even approximately correct. (See Exp. 129, Note.) The standard resistance may be increased by adding the various coils and rheostat wires, their values being known. _=349. Summary of Laws of Resistance.=_ 1. _The resistance of a wire is directly proportional to its length, provided its cross-section, material, etc., are uniform._ =EXAMPLE.= If 39.1 ft. of No. 24 copper wire has a resistance of 1 ohm, 78.2 ft. will have a resistance of 2 ohms, because 78.2 is twice 39.1; 70.38 ft. will have a resistance of 1.8 ohms, as (70.38 ÷ 39.1 = 1.8) it is 1.8 times 39.1. 2. _The resistance of a wire is inversely proportional to its area of cross-section._ The areas of cross-section of round wires vary as the squares of their diameters; so _the resistance of a wire is also inversely proportional to the square of its diameter, other things being equal_. =EXAMPLE.= A No. 30 wire has a diameter of about .01 inch, while the diameter of a No. 24 wire is about .02 in.; that is, the No. 24 has _twice_ the diam. that the No. 30 has. The area of cross-section of the No. 24, however, is four times that of the No. 30, so its resistance is but 1/4 that of the No. 30, the lengths, etc., being the same. (See Wire Tables.) 3. _The resistance of a wire depends upon its material, as well as upon its length, size, etc._ 4. _The resistance of a wire depends upon its temperature._ (See Elementary Electrical Examples.) CHAPTER XX. CURRENT STRENGTH. _=350. Strength of Current.=_ The water in a certain tank may be under great pressure, but if it is obliged to pass through long tubes before it can turn a water-wheel, for example, it is evident that the work done will depend not only upon the pressure in the tank, but upon the resistance to be overcome before the water gets to the wheel. The work that the water can do depends upon its _rate of flow_, and may be used to measure the _strength_ of the current. The strength of a current of electricity is measured also by the _work_ that it can do, and it depends upon its _rate of flow_ at the point measured. The strength may be determined from its magnetic, heating, or chemical effects. _=351. Unit of Current Strength; The Ampere.=_ A current having the strength of 1 ampere, when passed through a solution of silver nitrate under proper conditions, will deposit 0.001118 gramme of silver in _one second_; if passed through a solution of copper sulphate, copper plates being used for the electrodes, in the solution, 0.0003277 gramme of copper will be deposited in _one second_. (See Chemical Effects of the Current.) The thousandth of an ampere is called the milliampere. The strength of a current is proportional to the amount of chemical work that it can do per second. (See § 357.) _=352. Measurement of Current Strength.=_ The _galvanoscope_ previously described simply shows the presence of a current, or whether one current is larger or smaller than another. When the degree-card is used to get the relative deflections, the instrument may be called a _galvanometer_. _=The Tangent Galvanometer=_ is made on the same general idea as our galvanoscope, the diameter of the coil being twenty times, or more, the length of the needle. In these the strengths of the two currents compared are proportional to the tangents of the angles of deflection produced. (See Elementary Electrical Examples.) There are several varieties of galvanometers, each designed for its special work. They are often calibrated or standardized so that the amperes of current passing through them can be read off directly from the scale. _=353. The Ammeter=_ is really a galvanometer from which may be read directly the strength of a current. The coil has a low resistance so that it will not greatly reduce the strength of the current to be tested. _=The Voltameter=_ measures the strength of a current by chemical means. _=354. Unit of Quantity; The Coulomb.=_ A current having a strength of 1 ampere will do more chemical work by flowing one hour than it can do in 1 second. In speaking of the _quantity_ of electricity we introduce the element of _time_. The unit of quantity is called the _coulomb_, just as a cubic foot of water may be taken as a unit of quantity for water. A coulomb is the quantity of electricity given, in one second, by a current having a strength of 1 ampere. Coulombs are found by multiplying amperes by seconds; thus, a current of 5 amperes will give 20 coulombs in 4 seconds. _=355. Electrical Horse-power; The Watt.=_ The electric current has power to do work, and we speak of the horse-power of an electric motor in the same way as for a steam-engine. A current with the strength of 1 ampere and an E. M. F. of 1 volt has a unit of power called the watt. 746 watts make an electrical horse-power. Watts = amperes × volts. Watts ÷ 746 = the number of horse-power. (See Transformers, also Elementary Electrical Examples.) _=356. Ohm's Law.=_ It was first shown by Ohm that the strength of a current is equal to its E. M. F. divided by the resistance in the circuit; that is, Strength of current (amperes) = E. M. F. (volts). / resistance (ohms). If we let C stand for the strength in amperes, E for the E. M. F. in volts, and R for the resistance in ohms, we have the short formula, easily remembered, C = E/R _=357. An Ampere=_ would be produced by a current of 1 volt pushing its way through a resistance of 1 ohm. Knowing any two of the three, C, E, or, R, the other may be found. The resistance, R, it must be remembered, is the total resistance in the circuit, and is composed of the total internal and external resistances. (See Elementary Electrical Examples.) _=358. Internal Resistance and Current Strength.=_ It is evident that the internal resistance of a cell varies with the position and size of the plates. We shall now study the effects of these changes upon the strength of the current. [Illustration: Fig. 108.] =EXPERIMENT 142. Having a cell with LARGE PLATES, to find how the strength of the current is affected by changes in the position of the plates, the external resistance being small.= _Apparatus._ Galvanoscope, G V; materials for simple cell (Exp. 110); connecting wires. Arrange as in figure 108, omitting the wooden cross-piece. =359. Directions.= (A) Connect the wires with the 5-turn coil of G V, which has but little resistance. Have the tumbler nearly full of dilute acid to get the effect of large plates; that is, the current has a large liquid conductor to pass through in the cell, and the _internal_ resistance will be small. G V should be properly placed N and S. (B) Place the copper and zinc plates as far apart as possible in the acid, and press them against the bottom of the tumbler. Note the reading of G V. It is not necessary to take readings with reversed current. (C) Still pressing them against the bottom of the glass, to keep the same amount of surface under acid, slowly bring them near each other and watch the needle. (D) Hold the plates about an inch apart, and against the bottom, and note the reading of G V. Slowly raise the plates, keeping them the same distance apart until they are out of the acid. Watch the action of the needle. Make a note of your readings in degrees and write your conclusions. Does a change in internal resistance affect the strength of the current? =EXPERIMENT 143. Having a cell with SMALL PLATES to find how the strength of the current is affected by changes in the position of the plates, the external resistance being small.= _Apparatus._ Same as in Exp. 142, the acid, however, being but 1 in. deep in the tumbler; that is, we have the effect of a cell with small plates, each being about 1 in. by 1/2 in. =360. Directions.= (A) Repeat (B) and (C) of Exp. 142, recording the reading of G V in each case. (B) Compare the results with those of Exp. 142, remembering that the _internal_ resistance is larger than before. Is the current as strong with small plates as with large plates when the external resistance is small? When the external resistance is small (the 5-turn coil, for example), should the cell have a high or low internal resistance to produce the greatest effect upon the needle? [Illustration: Fig. 109.] =EXPERIMENT 144. To find whether the changes in current strength, due to changes in internal resistance, are as great when the external resistance is large, as they are when the external resistance is small.= _Apparatus._ Same as for Exp. 142, 143, also the rheostat containing the two meters of G-s wire (Exp. 121). =361. Directions.= (A) Arrange as in Fig. 109, the external resistance being 2 meters of No. 30 G-s wire in series with G V. The 2-F C in the Fig. is replaced, however, by the simple cell as in Exp. 143. (B) Find the effect upon the strength of the current of moving the plates about when but 1 in. of acid is in the tumbler. (C) Nearly fill the tumbler with acid and repeat (B), taking readings with plates near each other and as far apart as possible. Lift them nearly out of the acid and take the reading. (D) Still increase the external resistance of the circuit by adding coils of wire or the meter of No. 28 G-s wire and repeat. Is the strength of the current greatly affected by _slight_ changes in the internal resistance when the external resistance is large? _=362. Discussion.=_ We shall study, by means of figures, how changes in internal resistance affect the strength of the current. Let R stand for the total external resistance of a circuit, and r for the total internal resistance of the cell or cells; ohm's law, then, will be expressed by C = E / (R + r) =EXAMPLE.= Let us take a circuit (A) when the external resistance, R, is small, and (B) when R is large compared with r, E being taken as 1 volt in both cases. (A) Let R = 1, and r = 2; substituting these values in the formula above, we have: C = 1 / (1 + 2) = 1 / 3 = .33+ ampere. Now let the internal resistance, r, be slightly increased from 2 to 3 ohms; the value of C then becomes 1/4 ampere, as R + r = 4. The change in C, then, is the difference between 1/3 and 1/4; and this expressed in decimals becomes .33 - .25 = .08 ampere. (B) Let R = 200 ohms, and r = 2 ohms as in (A). Substituting these values we have, C = 1 / (200 + 2) = 1 / 202 = .00495 ampere. Increasing r from 2 to 3, as before, etc., we find that C = 1 divided by 203 = .00492 ampere. The above shows clearly (A) that the value of C is changed considerably by changes in r when R is _small_, and (B) that changes in r produce very slight changes in C when R is _large_. Review your results of Exps. 142-144. (See Elementary Electrical Examples.) _=363. Arrangement of Cells and Current Strength.=_ We have seen that internal resistance affects current strength. In joining cells, then, attention must be given to the internal resistance as well as to the E. M. F. of the combination. _=364. Cells in Series.=_ It has been shown by careful experiments that the E. M. F. of two cells joined in series (Fig. 110) is equal to the sum of the E. M. F. of each. Ten cells, joined in series, have ten times the E. M. F. of one cell, provided they have the same E. M. F. As the Zn of one is joined to the Cu of the other, the current is obliged to pass through one solution after the other; that is, the internal resistance of the two in series is equal to the sum of their internal resistances. Ten cells, joined in series, have ten times the internal resistance of one cell, provided they have equal internal resistances. [Illustration: Fig. 110.] [Illustration: Fig. 111.] _=365. Cells Abreast.=_ When the positive plates are joined together and the negative plates are also joined together (Fig. 111), the cells are said to be _abreast_, _in parallel_, or in _multiple arc_. It has been shown that two cells of equal strength, joined abreast, have the same E. M. F. as one cell. The two Cu plates, being joined, must have the same potential; all the Zn plates have the same potential, so the difference of potential at the terminals of the combination is the same as that at the terminals of a single cell. In two cells abreast (Fig. 111) the current has two liquid paths, side by side, to get from Cu to Zn; this makes the internal resistance one-half that of one cell, provided their internal resistances are equal. Ten cells, of equal internal resistance, when joined abreast, have one-tenth the internal resistance of one cell. =EXPERIMENT 145. To find the best way to join two similar cells when the external resistance is small.= _Apparatus._ Two simple cells using dilute sulphuric acid, with copper and zinc elements, as in Exp. 112; galvanoscope, G V; connecting wires, etc. Have the zincs well amalgamated. Remove them from the acid as soon as readings are taken. =366. Directions.= (A) Partly fill the tumblers with the acid. Join the cells in series (Fig. 110), then connect wire 1 (Fig. 110) with the left-hand binding-post of G V, and wire 2 with the middle one, thus putting the 5-turn coil into the circuit. Take the reading of G V. (B) Join the cells in multiple arc (Fig. 111), connecting them as in (A) with G V. Write down the reading, and compare it with that found in (A). (C) Take the reading with but 1 cell joined to G V. =EXPERIMENT 146. To find the best way to join two similar cells when the external resistance is large.= _Apparatus._ Same as for Exp. 145, also the rheostat containing 2 metres of No. 28 or 30 G-s wire. Arrange the G-s wire in series with the 15-turn coil of G V, as shown in Fig. 109, two simple cells being used, however, instead of 2-F C as shown. =367. Directions.= (A) Take the reading of G V when the two cells are in series (Exp. 145), the external resistance being the 15-turn coil and G-s wire. (B) Join the cells in parallel and take the reading, using the same external resistance as in (A). (C) Increase the external resistance by adding coils of wire or 2 metres of No. 28 G-s wire and repeat (A) and (B). What does the experiment show? (D) Take the reading with 1 cell and large external resistance. _=368. Best Arrangement of Cells.=_ It will be seen by experiments that with a given number of cells the strongest current is produced when they are arranged so that the internal resistance of the battery nearly equals the external resistance of the circuit. When the external resistance is small, the internal resistance may be kept down by joining the cells in parallel; and, although the E. M. F. is also kept small, the value of C will be larger than it would be with a larger internal resistance and a larger E. M. F. When the external resistance is large, the internal resistance can be made large by joining the cells in series. The advantage comes, however, from having a large value of E. A large resistance can not hold back a current of large E. M. F. By joining the cells in series the value of E is made large, and the value of C becomes large even though there is an increased internal resistance. (See Elementary Electrical Examples.) CHAPTER XXI. CHEMICAL EFFECTS OF THE ELECTRIC CURRENT. _=369. Chemical Action and Electricity.=_ We have learned that the electric current is produced, in the cell, by chemical action. There is a definite relation between the chemical action and the current produced. We are now to study the changing of electrical energy back, again, to chemical energy. [Illustration: Fig. 112.] _=370. Electrolysis=_ is the name given to the process of decomposing chemical compounds by passing the electric current through them. The compound decomposed is the _electrolyte_. Fig. 112 shows a tumbler of liquid (electrolyte) through which the current is to pass in the direction of the arrow. Two carbon plates, A and C, are in the liquid, and are joined to the source of electricity. The current enters at A (_anode_) and leaves at C (_cathode_). [Illustration: Fig. 113.] =EXPERIMENT 147. To study the electrolysis of water.= _Apparatus._ The two simple cells (§ 275) joined in series (§ 364), although two Daniell or two dry cells will be better. A tumbler of water containing a few drops of sulphuric acid to make the water a conductor. Two pieces of sheet copper will serve as the electrodes. The galvanoscope may also be put into the circuit as in Fig. 113. =371. Directions.= (A) Allow the current to pass, and note (1) whether gas is set free at both electrodes, A and C, and (2) at which the quantity of gas is the greater. If very little gas is produced use more cells. (B) Remove A and C from the liquid, to remove the gas, then watch the action of the needle of G V as the water is again decomposed. _=372. Composition of Water.=_ The two gases liberated in Exp. 147 were hydrogen (H) and oxygen (O). The chemical formula for water is H_{2}O, which means that it is composed of two parts, by volume, of H and one part of O. With proper apparatus these gases may be collected, tested, and the amounts measured. _=373. Electromotive Force of Polarization.=_ We know that H and O have a strong chemical attraction, or affinity, for each other. In order, then, for the current to decompose water, this attraction between the gases must be overcome; and as soon as the current ceases, these gases try to rush together again to form water. This sets up an electromotive force of almost 1.5 volts; in fact, a current is produced if the H and O be allowed to form water again (See Storage Cells). To decompose water the current must have an E. M. F. of over 1.5 volts to overcome this E. M. F. of polarization. It was seen in the study of simple cells that the current became rapidly weaker as hydrogen was deposited upon the copper plate, on account of this opposing electromotive force. In decomposing other compounds, the anode is made of the metal which is to be deposited at the cathode. If copper is to be deposited from a solution of copper sulphate the anode should be a copper plate; this keeps the solution at same strength, and avoids the opposing E. M. F. of polarization; that is, a very weak current will do the work (See Exp. 149), because the electrodes are of the same metal. =EXPERIMENT 148. To coat iron with copper.= _Apparatus._ Iron nail, solution of copper sulphate (§ 283). =374. Directions.= (A) Clean the nail with sandpaper, then hold it in the copper solution for a few seconds. Machinists often cover iron or steel tools with a thin coating of copper in this way. [Illustration: Fig. 114.] =EXPERIMENT 149. To study the electrolysis of a solution of copper sulphate.= _Apparatus._ Galvanoscope, G V; two-fluid cell, 2-F C; a tumbler, T, containing about an inch of copper sulphate solution (§ 283); a wooden cross-piece to which is fastened a copper strip; carbon rod, C; wire 2 is held to C by a rubber band. _Arrange_ as in Fig. 114, so that Cu will be the _anode_ (§ 370), the current passing as shown by arrow. A dry cell may be used for short experiments instead of the 2-F C. =375. Directions.= (A) The carbon being clean, allow the current to pass, C and Cu being kept about 1/2 in. apart. Watch the surface of C, and note the beautiful color of the deposited copper. Save the coated rod for the next experiment. Has the Cu plate been acted upon? _=376. Electroplating=_ is the name given to the process of coating substances with metal with the aid of the electric current. The copper sulphate, CuSO_{4}, is broken up into Cu and SO_{4} by the current. The Cu goes to the cathode, and the SO_{4} attacks the anode, gradually dissolving it if it be copper; that is, the _metal_ part of CuSO_{4} is carried in the direction of the current. Most metals are coated with copper before they are silver or gold plated. A solution of silver is used for silver plating, silver being used as the anode. =EXPERIMENT 150. To study the chemistry of electroplating.= _Apparatus._ Same as in last experiment, but use two carbon rods for the electrodes. Arrange as in Fig. 114, with the Cu replaced by another carbon. Two simple cells (§ 275) are also needed. =377. Directions.= (A) Allow the current to pass as before. Is copper still deposited? Does anything occur now at the surface of the anode? Is the copper deposited as rapidly as before? (B) Try the effect of the two simple cells joined in series, Instead of the two-fluid cell. (C) After a fair coating of copper has been deposited upon the carbon cathode, reverse the direction of the current through the copper solution; that is, use the coated rod for the anode. Allow the current to pass until a change takes place in the anode. _=378. Discussion.=_ Ions are the names given to the parts into which an electrolyte is decomposed by the electric current. In the case of CuSO_{4}, the ions are Cu and SO_{4}, which is called an acid radical. This SO_{4} can not dissolve carbon or platinum, so these are used when water is to be electrolyzed. Where copper is used as the anode for copper plating, the SO_{4} attacks it, forming CuSO_{4} again, and this keeps the solution strong. If carbon were used instead, the SO_{4} would take H_{2} from the water around the anode and H_{2}SO_{4} (sulphuric acid) would be formed, the oxygen of the water being set free at the anode. The amount of Cu dissolved from the copper anode equals nearly the amount deposited upon the cathode. Exp. 150 shows that the metal is carried in the direction of the current. As hydrogen is produced at the cathode it is chemically considered a metal. _=379. Electrotyping=_ consists in making a copy in metal, of a woodcut, page of type, etc. A mould or impression of the type is first made in wax, or other suitable material (the pages of this book, for example, as set up by the printer). These moulds are, of course, the reverse of the type. They are coated with graphite to make them conduct electricity, and hung as the cathode, in a bath of copper sulphate. After a thin coat of copper has been deposited by an electric current, the wax is removed and the thin copper backed with soft metal. The metal surface next to the wax will be just like the type, only made of copper. These plates or _electrotypes_ can be printed from, the original type being used to set up another page. (See "Things a Boy Should Know About Electricity.") _=380. Voltameters=_ are cells used to measure the strength of an electric current. In the _Water Voltameter_ the hydrogen and oxygen produced are measured. The H acts like a metal and goes to the cathode, two parts of H being formed to one of O. _Copper Voltameter._ This cell measures the amount of copper deposited in a given time by a current. The copper cathode is weighed before and after the current flows. The weight of Cu deposited is then divided by the number of seconds during which the current passed, and this result, in turn, by .000328, which will give the average strength of the current in amperes. (See § 351.) Other forms of voltameters are also used. In all voltameters the quantity of metal deposited is proportional to the time that the current flows, and to its strength. [Illustration: Fig. 115.] =EXPERIMENT 151. To study the construction and action of a simple "storage" cell.= _Apparatus._ Two lead plates, L P, (Nos. 77, 78) fastened to a wooden cross-piece (§ 275). The spring-connectors should not be forced upon the thick lead. Fasten one end of the wire under the screw-head. A tumbler two-thirds full of dilute sulphuric acid (§ 258); the astatic galvanoscope, A G; wires to form connections; the two simple cells joined in series. _Arrange_ as in Fig. 115. One L P is joined to binding-post, L, of A G by the wire marked 1; wire 2 connects the other L P to the copper Cu. Wire 3 joins the zinc to any thin metal plate, M P, which is used for convenience, so that the spring connectors can be quickly slipped on or off. Wire 4 joins M P with binding-post R of A G. =381. Directions.= (A) Get clearly in mind the direction in which the right-hand end of the astatic needle is deflected when the current passes, remembering that it passes into A G at L and leaves at R. Allow the current to flow for 10 or 15 minutes through the circuit, at the same time watching the needle to see whether the strength of the current remains constant. (B) Remove the connector from Cu, swing it over into the position of the dotted line (Fig. 115), slip the connector upon M P and watch the needle. This cuts the cells out of the circuit; but, if you desire, also remove wire 3 from M P. Does the storage cell, S C, produce any current? Does it pass through A G in the same direction as that which came directly from the two cells? (C) Try the dry cell in place of the two simple cells. Try 2 other cells in series if you have them. _=382. Secondary or Storage Cells=_ must be charged by a current before they can give out a current. _Electricity_ is not really stored. Chemical changes are produced in the storage cell by the charging current, as in the voltameter or electroplating bath; and it is, then, potential chemical energy that is stored. When the new compounds are allowed to go back to their original condition by joining the electrodes of the charged cell a current is produced. In other words, an electric current produces chemical changes in the cell by electrolysis, and these new compounds have an E. M. F. of polarization because they are constantly willing and anxious to get back to their old state. The plates are lead and are usually coated with compounds of lead. Hydrogen and oxygen are given out at the electrodes. The current from a dynamo is used to charge secondary batteries. (See "Things a Boy Should Know About Electricity.") CHAPTER XXII. ELECTROMAGNETISM. _=383. Electromagnetism=_ is the name given to magnetism that is developed by electricity. You have already seen that if a magnetic needle be placed in the magnetic field of a _magnet_, its N pole will point in the direction in which the lines of force pass on their way from the N to the S pole of the magnet. You have also seen that in the galvanoscope, etc., a coil of wire acts like a magnet when a current passes through it. Can we not, then, use the needle to study the lines of force about wires and coils? [Illustration: Fig. 116.] [Illustration: Fig. 117.] =EXPERIMENT 152. To study the lines of magnetic force about a straight wire carrying a current.= _Apparatus._ The compass, O C; key, K; dry cell, D C. Arrange as in Fig. 116. =384. Directions.= (A) Arrange the wire so that the current will flow through it from N to S over the compass-needle as soon as the circuit is closed (Fig. 117, A). Press K for an instant only, and note the direction in which the N pole is deflected. Repeat two or three times until you get clearly in mind the direction taken by the needle. Sketch the result in your note-book, and compare with Fig. 118, A. The arrow shows the direction of the current. (B) Let the current pass for an instant from N to S and _under_ the needle, as shown in Fig. 117, B. Sketch result. (C) Let the current pass for an instant from S to N _above_ the needle (Fig. 117, C). Sketch result. (D) Let it pass from S to N _under_ the needle (Fig. 117, D). Sketch result. (E) Let it pass through the wire from east to west (Fig. 117, F) above the needle, then under it, and note result. Compare the results with those indicated in Fig. 118. [Illustration: Fig. 118.] [Illustration: Fig. 119.] _=385. Lines of Force About a Wire.=_ When a current passes through a wire, the needle, over or under it, tends to take a position at right angles to the wire. This shows that the lines of force pass _around_ the wire and not in the direction of its length. The needle does not swing entirely perpendicular to the wire; that is, to the E and W line, because the earth is at the same time pulling its N pole towards the N. If the needle had no pointing power, and at the same time retained its magnetic field, it would point exactly at right angles to the wire as soon as the current passed. If you look along the wire, Fig. 119, from the point, C, towards the positions, A and B, you will see (A) that _under_ the wire the lines of force pass to the left, and that _above_ the wire (B) they pass towards the right. This is because the N pole points in the directions mentioned. (See Fig. 118.) Looking along the wire from Z towards position, D and C, you will see just the opposite to the above, as the current comes _towards_ you. _Rule._--When the current goes from you, the lines of force pass around the wire in a clockwise direction, and when the current comes toward you they pass around it in an anti-clockwise direction. _=386. Ampere's Rule=_ may be used to remember what has been learned in Exp. 152. _If you imagine yourself swimming in the wire with the current, always facing the needle, the N-seeking pole of the needle will always be deflected towards your left hand._ When the needle is above the wire you must imagine that you swim upon your back, in order to _face_ the needle. _Another Rule._--Hold the right hand with the thumb extended and with the fingers pointing in the direction of the current, the palm being towards the needle and on the opposite side of the wire from the needle. The N-seeking pole will then be deflected in the direction in which the thumb points. _=387.=_ If a wire carrying a strong current be dipped in iron filings, the magnetic field about the wire acts by induction upon the particles of filings, making magnets of them. These cling to each other simply because they are little magnets. _=388. Lines of Force about Parallel Wires.=_ When a current passes in the same direction in two parallel wires the lines of force pass around the wires in the same direction in both, and the magnetic fields attract each other. When the currents flow in opposite directions the magnetic fields repel each other. =EXPERIMENT 153. To study the lines of force about a coil of wire like that upon the galvanoscope.= _Apparatus._ Galvanoscope, G V; dry cell; key; compass. Arrange as in Fig. 116, using G V instead of the compass shown. The coil of G V should be placed in the E and W line. The current can pass only when the key is pressed. Connect the wires with G V, so that the current will pass through the 15-turn coil from W to E on top of the coil; that is, so that the current will have a "clockwise" motion. Fig. 120 represents a front view of the coil. [Illustration: Fig. 120.] [Illustration: Fig. 121.] =389. Directions.= (A) Hold the compass in the various places marked with a dot (Fig. 120) and note the directions taken by its N pole. Make a circle similar to the one shown to represent the coil, and sketch upon it the way in which the lines of force pass around it according to your observations. (B) Make a diagram like Fig. 121, which represents a cross-section of the coil through the center. Imagine that you have removed the top half of the coil and that you are looking down upon the ends of the wire of the lower half. Draw curved arrows about the coil at W and E to show which way the lines of force are passing. Compare your results with those in Fig. 119, remembering that at E, Fig. 121, the current is going away from you. (C) Move O C back and forth on the center-line that runs N and S through the coil, and note the positions of the compass-needle. Does the coil seem to have poles? (D) Reverse the current through the coil and repeat your observations. =EXPERIMENT 154. To study the magnetic field about a small coil of wire.= _Apparatus._ A coil of wire (No. 89), described in § 390; current reverser, C R (No. 57); dry cell; connecting wires, etc. =390. Coils= of wire for some of the following experiments should be wound upon wooden spools that have been turned down thin, so that the wire will be as near the central hole as possible. They should be wound with a winder. (See Apparatus Book, Chapter X.) For convenience we shall call the starting end of the coil, that is, the end that comes from the wire that is near the center, the _inside end_, I E. The end of the last layer of the coil we shall call the _outside end_, O E. These letters should be noted in the diagrams. See Apparatus List for details of the special coils used in these experiments. [Illustration: Fig. 122.] =391. Directions.= (A) Arrange as in Fig. 122, so that the axis of the coil will lie in the E and W line. Place O C about 2 in. from the E end of the coil. Press one lever of C R so that the current will pass around the coil for an instant in a clockwise direction; that is, so that it will enter the coil at O E. Note the action of the needle. If the needle is not affected move it nearer the coil and press the lever again. Get clearly in mind the connections, the direction in which the N end of the needle is deflected, etc. Is the E end of the coil a N or a S pole? (B) Reverse the current through the coil. What effect has it upon the polarity of the E end of the coil? (C) Place O C at the west end of the coil and repeat (A) and (B). (D) Place O C in various positions about the coil and note the action of the needle when the current passes. Does this coil act like a magnet, having poles, magnetic field, etc.? [Illustration: Fig. 123.] _=392. Polarity of Coils.=_ It is evident from Exps. 153 and 154 that a coiled conductor has poles, magnetic field, etc., when a current passes, and that it strongly resembles a magnet, even though no iron enters into its construction. We may say that the coil becomes magnetized by the electric current. Fig. 123 shows a right handed coil or helix of wire, the current passing as shown by the small arrows. The left-hand end is a S pole because the current passes around it in a clockwise direction. When you face the right-hand end of the coil the current is seen to pass around it in an anti-clockwise direction; this produces a N pole. As the N pole of the magnetic needle is attracted toward the S pole of the coil, it is clear that the lines of force pass through the inside of the coil as shown by the large arrows. They then curve through the air and return to the S pole as with magnets. =EXPERIMENT 155. To test the attracting and "sucking" power of a magnetized coil or helix.= _Apparatus._ The coil, battery, etc., used in Exp. 154, Fig. 122; a sewing-needle. [Illustration: Fig. 124.] =393. Directions.= (A) Arrange the coil, etc., as described in Exp. 154. The coil need not lie in the E and W line, however, and a key may be used instead of the current reverser. (B) Magnetize the needle so that its point will be a N pole. (C) Tie a thread about the center of the magnetized needle, hold the thread in the hand so that the S pole of the needle will swing freely at the hole at the right-hand end of the coil (Fig. 124). If the current passes as directed, the right-hand end of the coil will be a N pole. What happens to the needle when the key is pressed for an instant. (D) Change the needle to the left end of the coil and repeat. (E) Try a nail, pen, iron, etc., instead of the needle. =EXPERIMENT 156. To find whether a piece of steel can be permanently magnetized by an electric current.= _Apparatus._ Same as for last experiment; an unmagnetized sewing-needle; the compass. =394. Directions.= (A) Be sure that the needle is not magnetized. It should attract both ends of the compass-needle. How can any magnetism in the needle be removed? (B) Place the needle inside of the coil with its _point_ to the east; that is, with its point at the N pole of the coil, and its head at the S pole. Close the circuit for an instant. Test the needle again for poles. Is the point a N or a S pole? (C) Turn the needle end for end in the coil, and see whether its polarity can be reversed. (D) Experiment with iron wire, nails, steel pens, spring steel, etc. [Illustration: Fig. 125.] =EXPERIMENT 157. To study the effect of a piece of iron placed inside of a magnetized coil of wire.= _Apparatus._ Same as in Exp. 154; a short rod or iron _core_, I C, of soft iron (No. 92) that will fit inside of the coil. This combination is called an electromagnet. =395. Directions.= (A) Arrange first as for Exp. 154, Fig. 122, with the coil in the E and W line, no core being used, and place O C about 6 in. from the right-hand end of the coil. (B) Press the lever for an instant to see whether the field of the coil is strong enough to move the compass-needle at that distance. Move O C a little nearer or farther from the coil until the needle _just_ moves, when the circuit is closed. (C) Place I C inside of the coil (Fig. 125), and repeat (B) to see whether the magnetic field of the coil is stronger or weaker than before. (D) Study the location of the poles. Can they be reversed? CHAPTER XXIII. ELECTROMAGNETS. _=396. Electromagnets=_ are important to the student of electricity. They form the principal part of nearly every electrical instrument. You have seen that a wire has a magnetic field about it the instant a current passes through it. A coil, or helix of wire, has a stronger field than a straight wire carrying the same current, because each turn, or convolution, adds its field to the fields of the other turns. By having a _core_ of soft iron instead of air, wood, or other non-magnetic material, the strength of the magnet is greatly increased. The central core may be permanently fixed in the coil, or it may be removable. (See Apparatus Book, Chapter IX, for Home-made Electromagnets.) _=397. Cores of Electromagnets.=_ A strong magnet has more lines of force passing from its N pole through the air to its S pole than a weak magnet. By increasing the number of lines of force we increase the strength of a magnet. It has been seen, in experiments with permanent magnets, that lines of force do not pass as readily through air as through soft iron, and that lines of force will go out of their way to pass through iron. It was learned in Exp. 154 that inside of a helix (Fig. 123) the lines of force pass from the S to the N pole; they then spread out through the air and pass back on all sides of the coil to its S pole, as in the case of permanent magnets. The air around and inside of a helix offers a great resistance to the lines of force, and tends to weaken the magnetic field. When part of the circuit consists of an iron core, which is a splendid conductor of lines of force, the magnetic field is greatly increased in strength. =EXPERIMENTS 158-163. To study straight electromagnets.= _Apparatus._ A good dry cell or other source of a fairly strong current; coil with soft iron core; key; wires with connectors, etc.; small nails; iron-filings; compass; large wire nail; tin box (No. 94) to act as a base for the electromagnets. =EXPERIMENT 158. Lifting power.= =398. Directions.= (A) Join the cell, key, and coil, as explained in Exp. 154, so that the current will pass only when the key is pressed. Place the core inside of the coil (Fig. 125). Two good cells in series can be used to advantage. (B) Hold the coil in a vertical position near small nails, iron filings, tin boxes, etc.; then press the key and raise coil; carry the clinging iron to another place, break the circuit at the key, and explain the result. Why do nails cling more strongly to the core than filings after the circuit is broken? =EXPERIMENT 159. Residual magnetism of core.= =399. Directions.= (A) After the current has passed through the coil with the core in place, remove the core and test it for magnetism with the compass. Will the small end of the core attract both poles of the compass-needle, or is it slightly magnetized? (B) If there is any residual magnetism, strike the core with a hammer and test again. (C) Use a soft steel wire nail for the core, and repeat (A) and (B). Why does soft iron make a better core than steel for electromagnets? Which should be the more easily magnetized? =EXPERIMENT 160. Magnetic tick.= =400. Directions.= (A) Join the electromagnet with the cell and key as before (Exp. 154). Hold one end of the core firmly against the top of a tin box which should stand upon the table and which should act as a sounding-board. The flat boxes used in the experiments on static electricity are good for this, or use the tin box, No. 94, for a base. Rapidly open and close the circuit by means of the key and listen for any clicks made by the core. (B) Listen for this sound in telegraph sounders, electric bells, etc., if you have them. The armature should be held, of course, so that slight sounds can be heard. _=401. Discussion.=_ A bar of iron becomes slightly longer when it is magnetized, the particles of iron being made to point in the same direction. As soon as the current ceases to flow through the coil the particles of the soft core nearly all resume their mixed positions. The click heard is supposed to be due to the changes in the molecules of iron. The core becomes gradually warmer when it is rapidly magnetized and demagnetized by a strong current. [Illustration: Fig. 126.] =EXPERIMENT 161. Magnetic figures.= =402. Directions.= (A) Arrange as in Fig. 126. The key should be used in case a dry cell acts as the source of the current. Two good cells joined in series can be used to advantage. Lay the coil flat upon the table and place on it a piece of stiff, smooth paper, or a sheet of glass. (B) Sprinkle a few iron filings upon the glass, which may be held in place by books. Gently tap the glass with a pencil while you close the circuit at the key. Do the filings arrange themselves as in the case of permanent magnets? Make a sketch of the field, remembering that you have both N and S poles, and compare it with previous results. [Illustration: Fig. 127.] =EXPERIMENT 162. Magnetic figures.= =403. Directions.= (A) Arrange as in Fig. 126, but stand the coil on end, using the base as directed in § 407, to hold it firmly in position. Join the ends, O E and I E, to the key as before. Fig. 127 shows a top view of the coil and base. (B) With books, etc., fix a piece of stiff, smooth paper, or glass just over the top of the core, and proceed as in Exp. 161 to study the field. See § 417 for making permanent pictures of magnetic fields. =EXPERIMENT 163. Magnetic field.= =404. Directions.= (A) Use same arrangement as for Exp. 162, except filings and glass, which are replaced by the compass. (B) Hold the compass about 2 in. from the top pole of the electromagnet, close the circuit for a second or two and note action of needle. Is the top N or S, when the current enters the coil at O E? Compare result with § 392. (C) Move the compass quickly about the pole, the circuit being closed, and note action of needle. Compare result with directions taken by particles of iron filings in Exp. 163. (D) Reverse the direction of the current through the coil and test the nature of the pole at the top. [Illustration: Fig. 128.] [Illustration: Fig. 129.] _=405. Horseshoe Electromagnets.=_ Fig. 128 shows a simple form of electromagnet with two coils which have a bent piece of iron as a core for both. The coils have to be wound on by hand in this form. As this is troublesome, the coils are generally wound on two separate cores which are joined by a _yoke_ (§ 406), which takes the place of the curved part in Fig. 128. The separate coils can be quickly made with a "winder" and joined to suit. (See Apparatus Book, Chapter IX, for Home-made Electromagnets.) Fig. 129 shows a top view of a home-made experimental horseshoe electromagnet. The coils are joined by an iron strap, called the _yoke_, which is screwed to a wooden base. A strip of iron placed above the magnets to be attracted by them, when the current passes, is called the _armature_. (See Telegraph Sounders.) _=406. Use of Yoke.=_ It has been explained (§ 82) why horseshoe magnets are, in general, better than straight ones. The same is true of electromagnets; there are two poles to attract, and two to induce. The lines of force pass through the yoke on their way from one core to the other, and this reduces the resistance to them. The strength of the horseshoe magnet would be greatly reduced if the lines of force were obliged to pass through two air spaces instead of one; in fact, if there were no yoke we should have simply two straight magnets. The yoke should be made of soft iron. [Illustration: Fig. 130.] [Illustration: Fig. 131.] =407. Experimental Magnets= are quickly joined to a tin base (No. 94), which has 3 holes punched in, through which screws can be put to hold the cores in place. Fig. 127 shows plan of tin. Fig. 130 shows how removable cores are fastened to the base, the coils being on the spools, and Fig. 131 shows how home-made coils on bolts can be used. The coils on bolts should be wound as directed in Apparatus Book, Chapter X. The tin base also serves as the yoke. _Removable Cores._ Fig. 130. These are of soft iron (No. 92, 93). In one end of each is a hole for the screws, S. Part of the tin has been cut away in the Fig. The copper washer, C W, should be used. (See § 408.) Connectors are fastened to the ends of the coils (§ 226-230). _Bolt Cores._ Fig. 131. After winding on the coils, as directed in Apparatus Book, remove the nut and put on an extra washer, E W, so that the ends of the coils will not be pressed against the tin, but come out between the two washers. Push the screw-end of the bolt through holes (about 2 in. apart) punched in the tin, then put on the nut, as shown. Do not force the nut on too far,--just far enough to hold the cores in place. The ends of the wires are not shown in Figs. 130, 131. Connectors are fastened to them (§ 408). [Illustration: Fig. 132.] =408. Method of Joining Coils.= To produce the best results the poles of the horseshoe electromagnet should be unlike. As the coils are wound alike, their ends must be joined in such a manner that the current will pass around them in opposite directions; that is, if the current enters one coil at the outside end, O E, it must enter the other coil at the inside end, I E. Fig. 132 shows a plan of the connections, spring connectors being fastened to the coil-ends, to allow rapid and easy changes in the arrangement. L, M, and R are pieces of metal fastened to a strip of wood (No. 95), used to make connections from cells or other apparatus. They are turned up at each end as in Fig. 104, 3. Care should be taken not to get short circuits by allowing two wires to touch the tin base. By changing the ends of the coils upon L, M, and R (left, middle, and right), and by changing the direction in which the current enters the "combination connecting plates" (No. 95), it is evident that the nature of the poles can be regulated to suit. =EXPERIMENTS 164-173. To study horseshoe electromagnets.= _Apparatus._ Coils of wire with cores and yoke like those explained in this chapter. Coils fastened to tin base or yoke with wires leading from them to the combination connecting plates (No. 95, Fig. 132), are very handy. Cells; iron filings; compass; iron strip (No. 76). =EXPERIMENT 164. To test the poles.= =409. Directions.= (A) Arrange as in Fig. 126, but use the experimental magnets and combination connections (Fig. 132) in place of the single coil shown in Fig. 126. Join O of the key with L, and Zn of the cell with R of Fig. 132. When the key is pressed the current will enter the magnets from L and leave at R. (B) With the compass test the polarity of the cores as in Exp. 163, B, C. Make a sketch of the arrangement, and note which pole is N and which S. (C) See which way the current must pass around each coil, by the way it is wound, and compare the results of (B) with Exp. 154, Fig. 123. =EXPERIMENT 165. To test the poles.= =410. Directions.= (A) Arrange as in Exp. 164, but reverse the direction of the current through the coils. Do this by joining O of the key (Fig. 126) with R of Fig. 132, and Zn of the cell with L. (B) Repeat (B) and (C) of Exp. 164 and study results. [Illustration: Fig. 133.] =EXPERIMENT 166. To test the poles.= =411. Directions.= (A) Arrange all connections as in Exp. 164, then reverse the positions of O E and I E of coil A; that is, join O E to M, and I E to L, Fig. 132. This will make unlike ends come together at M; in other words, when the current enters at L and leaves at R it will pass around both coils in the same direction. (B) Study the nature of the poles, as in Exps. 164, 165, and note results. _Note._--Fig. 133 shows simply the two cores of a horseshoe electromagnet with arrows to indicate in which direction the current is passing in each coil to produce N and S poles. =EXPERIMENT 167. To study the inductive action of one core upon the other.= =412. Directions.= (A) Arrange as for Exp. 164, but join the wire from Zn of the cell to M (Fig. 132). In this way coil B will be cut out of the circuit. Place the coils in the E and W line. (B) Find about how far the residual magnetism of the core of B can act upon the compass-needle, holding the compass on the side away from coil A, no current passing. (C) Press the key for an instant, and note whether the magnetism of coil B has been made stronger or weaker. Explain the action of core A on core B. =EXPERIMENT 168. Magnetic figures.= =413. Directions.= (A) Arrange as in Exp. 164. With books, etc., fix a piece of smooth, stiff paper, or a sheet of glass, just above the poles of the electromagnets. (B) Sprinkle iron filings upon the glass, and gently tap it while the circuit is closed at the key for a few seconds. Make a sketch of the magnetic figure produced. Do the lines of force from the opposite poles attract or repel each other? See § 417 for making permanent figures. (See "Things a Boy Should Know About Electricity" for drawings of magnetic figures.) _Note._--If possible, use two or three good cells in series for making magnetic figures, as a fairly strong field is best. =EXPERIMENT 169. Magnetic figures.= =414. Directions.= (A) Arrange apparatus as for Exp. 165, and make the magnetic figure for this combination, as directed in Exp. 168. Sketch and study the results. =EXPERIMENT 170. Magnetic figures.= =415. Directions.= (A) Arrange the apparatus and connections as in Exp. 166, and make the magnetic figure of this combination as directed in Exp. 168. In this case the poles are alike. Sketch and study the results. =EXPERIMENT 171. Magnetic figures.= =416. Directions.= (A) Arrange apparatus and connections as in Exp. 167, and make the magnetic figure of the combination as directed in Exp. 168. Compare the figure produced with that of Exp. 168. In this case the current passes through but one coil. =417. Permanent Magnetic Figures= can be made in several ways for future study and comparison. (A) _Paraffine paper figures._ Make paraffine paper as directed in Apparatus Book, page 135. For this purpose smooth, stiff, _white_ paper is best, so that the filings will show plainly, and but a thin coating of paraffine should be given. Place the magnets upon the table, lay over them a piece of unparaffined paper, and fix the paraffine paper directly over this. This is necessary, as the coated paper sticks when heated. For electromagnets it will be necessary to support the edges of the paper with books, etc. Sprinkle on the filings and tap the paper to make them arrange themselves while the circuit is closed. After the lines of force show plainly, the current need not be used again, provided the paper be kept perfectly still. Pass the flame of a Bunsen burner over the paper to melt the coating. This will, no doubt, make the two pieces of paper stick together, and permanently fix the particles of filings in place. Do not heat the paper too much--just enough to melt the paraffine. If you have no gas, hold a fire-shovel, containing hot coals, over the paper. As soon as the paraffine cools, the figures will stand considerable handling. _Blue print figures_ are very pretty, and last indefinitely. Get some blue-print paper at a photographer's, who will give you directions about "developing" it with water. Keep this in the dark, and take out but one sheet at a time for experiments. To make the figures, take your apparatus near a window where bright sunlight comes in. Pull down the curtain so that you have but a dim light when you make the magnetic figure, as directed before. After the lines of force show plainly, raise the curtain, and let the bright sunlight shine on it for 5 or 6 minutes, or until the surface of the paper has a rich, bronze color. The paper cannot be acted upon by the light under the particles of filings. Quickly shake the filings from the paper, and wash it in 3 changes of water to "develop" it, then pin the paper up to dry. =EXPERIMENT 172. Lifting power.= =418. Directions.= (A) Arrange the apparatus as in Exp. 164. Hold an iron strip (No. 76), a screw-driver, or other iron bar directly over and near the poles of the experimental electromagnet. Close the circuit at the key, then lift the magnets by the "armature," as the iron strip may be called, the circuit being kept closed for a few seconds. If your cell is good there should be no trouble in lifting the magnets by the armature. Open the circuit, and see whether the magnets drop. (B) Hold the magnets upside down directly over nails, tin boxes, iron filings, or other pieces of iron. Close the circuit, move the attracted iron to another place on the table, and open the circuit. Can this principle be used for practical purposes? _Note._--Some experiments illustrating practical uses of electromagnets will be given in a future chapter. =EXPERIMENT 173. Residual magnetism when magnetic circuit is closed.= =419. Directions.= (A) Arrange as in Exp. 164. You have already seen that each core retains some magnetism after the circuit is closed. Place the iron strip firmly across the poles, close the circuit for an instant, open the circuit, then see whether the armature still clings to the cores with some strength. The armature should fit well upon the cores for this experiment. (B) Again press the armature upon the cores, no current being used; then lift it as in (A). Compare the attraction with that found in (A). _=420. Closed Magnetic Circuits.=_ It was seen in the study of the permanent horseshoe magnet, that the armature clung strongly to the magnet. The armature closed the magnetic circuit, the lines of force having almost no resistance. In the case of electromagnets the magnetic circuit becomes closed when the armature touches both poles at the same time. The armature clings strongly to the poles even after the current ceases to flow. As soon as the magnetic circuit is broken, however, but little residual magnetism remains. The armatures of electromagnets are usually arranged so that they can not quite touch the cores, to avoid this sticking. CHAPTER XXIV. THERMOELECTRICITY. [Illustration: Fig. 134.] =EXPERIMENT 174. To find whether electricity can be produced by heat.= _Apparatus._ The home-made thermopile described in §421; astatic galvanoscope; connecting wires; candle or alcohol lamp. =421. Home-made Thermopile.= (Fig. 134.) For this you need 3 hairpins, copper wire, a piece of wood about 3 in. long and 1 in. square on the ends, 2 pieces of tin, and some small nails. Straighten the hairpins and scrape the coating off with sandpaper or a file. Scrape the insulation from 4 pieces of copper wire, each about 8 in. long. Twist the ends of the copper wire about the ends of the hairpins (Fig. 134), and then fasten the hairpins to the block. They may be held firmly by small nails which should be driven partly into the block and bent over. The hairpins at the right-hand side of the Fig. are shown to be near but not touching each other. This allows all to be heated at the same time. The tin binding-posts may be nailed or screwed to the block, and if the bare copper wires 1 and 4 be placed under X and Y before they are screwed down they will be electrically connected. The ends of 1 and 4 may be held under the screw-heads. The block may be supported upon other blocks to raise it to the proper height, which will depend upon the length of the candle. [Illustration: Fig. 135.] A thermopile in the form of a circle with several pairs of metals, can easily be made by fastening the hairpins to a piece of cardboard (Fig. 135) with a hole at the center. This may be supported by blocks, the heat being applied under the center. =422. Directions.= (A) Arrange the apparatus as in Fig. 134. See that the astatic needle is properly adjusted, no magnets being near it. (B) Heat the joints as shown, and watch the needle. Can a current be produced by heat? (C) Remove the connector on wire 6 from Y to M, thus cutting one pair out of the circuit. Heat the joints again and compare the strength of the current with that produced in (B). (D) See whether much current is produced by one pair. From results obtained do you see any relation between the strength of the current and the number of pairs? _=423. Thermoelectricity=_ is produced by heating the junction between two metals. Different pairs of metals produce different results. Antimony and bismuth are often used. If the end of a strip of bismuth be soldered to the end of a similar strip of antimony, and the free ends be connected to a galvanometer of low resistance, the presence of a current will be shown when the point of contact becomes hotter than the rest of the circuit. The current will flow from the bismuth to antimony across the joint. By cooling the junction below the temperature of the rest of the circuit a current will be produced in the opposite direction. Thermoelectric currents have a low potential. The energy of the current is kept up by the heat absorbed. _=424. Peltier Effect.=_ The action noted in § 423 can be reversed; that is, if a current from a battery be sent through the metals, the parts at the junction become slightly warmer or cooler than before, depending upon the direction of the current. This is known as the _Peltier Effect_, the heat not being due to the resistance to the current. _=425. Thermopiles.=_ As the E. M. F. of the current produced by a single pair of metals is small, several pairs are usually joined in series in such a way that the different currents help each other and flow in the same direction. Such combinations, usually made of antimony and bismuth, are called thermoelectric piles, or simply thermopiles. They are useful in detecting very small differences in temperature. The heat of a match, or the cold of a piece of ice, will produce a current even at some distance, the thermopile being connected with a sensitive short-coil astatic galvanometer. (See "Things a Boy Should Know About Electricity.") CHAPTER XXV. INDUCED CURRENTS. _=426. Electromagnetic Induction.=_ You have seen, by experiments, that a magnet has the power to induce another piece of iron or steel to become a magnet. You have also seen, in the study of static electricity, that an electrified body has the power to act through space upon another conductor. A body may be polarized and charged with static electricity by induction. Several questions now come up. Can a _current_ of electricity in a conductor induce a _current_ in another conductor not in any way connected with the first? Can current electricity produce effects through space? Is there an electromagnetic induction? It has been seen that a current-carrying wire has a magnetic field, and that magnetic fields can act through space. It is evident, then, that a conductor will be surrounded and cut by lines of force when it is placed in a magnetic field, or near a wire or coil through which a current passes. Let us study this by experiments. =EXPERIMENTS 175-182. To study induced currents.= _Apparatus._ The two coils of wire (Nos. 89, 90); two short, soft iron cores (Nos. 92, 93); long iron core (No. 96); bar magnet (No. 97); astatic galvanoscope (No. 59); dry cell (No. 51); key (No. 55); horseshoe magnet; connecting wires with spring connectors (No. 54) on the ends (§ 226-230); coil of wire (No. 98) wound on an iron core; compass. [Illustration: Fig. 136.] =EXPERIMENT 175. To find whether a current can be generated with a bar magnet and a hollowed coil of wire.= =427. Directions.= (A) Arrange as in Fig. 136. The coil (No. 90) of fine wire is joined to A G (No. 59) as shown. Small pieces of tin or copper, 1 and 2, are used to make connections between the coil ends and wires, 3 and 4, which are attached to the galvanoscope. It is best to use the wires, 3 and 4, so that the coil will be 2 feet at least, from A G; otherwise the needle of A G might be affected by the magnet, M (No. 97). (B) Get clearly in mind in which direction the right-hand end of the needle is deflected when a current enters A G at L, the left-hand binding-post. If you have forgotten the results of previous experiments, use the cell for an instant, touching the wire from the carbon to L and that from the zinc to R. If any currents come from the coil, later, you should be able to tell in which direction they flow, the coil and A G forming a closed circuit. (C) Hold the magnet, M, as shown, and quickly push it into the coil until it has the place of a core, at the same time watching the needle. If a current is produced, in which direction does it flow from the coil? Does the needle remain deflected? Is the current constant or temporary? (D) After the magnet, M, has been placed in the coil, as in (C), and the needle has come to rest, quickly pull M from the coil, watching the needle. If a current is produced, does it pass from the coil in the same direction as before, in (C)? (E) Turn M end for end, repeat (C) and (D), and study the results. Are lines of force made to cut the turns of the coil? (F) Repeat (C) and (D), moving M slowly. _=428. Discussion.=_ An induced current, produced as in the above experiment, is a momentary one. No current passes when the magnet and coil are still; at least one of them has to be in motion. When the magnet is inserted, the induced current is said to be an _inverse_ one, as it passes in a direction opposite to that which would be necessary to give the magnet its poles, it being considered a core magnetized by the current. A _direct_ current is produced when the magnet is withdrawn from the coil. Rapid movements produce stronger currents than slow ones. (See § 439.) _=429. Induced Currents and Work.=_ It takes force to move a magnet through the center of a coil, and it is this work that is the source of the induced current. When the coil is pushed on to the magnet, or when it is moved through a magnetic field, force is also required. We have, in this simple experiment, the key to the action of the dynamo and other important electrical machines. These will be discussed later. =EXPERIMENT 176. To find whether a current can be generated with a bar magnet and a coil of wire having an iron core.= =430. Directions.= (A) Arrange as in Exp. 175, Fig. 136, and, in addition, place an iron core (No. 92) inside of the coil (No. 90). (B) Hold the bar magnet (No. 97) as in Fig. 136, and quickly lower it until it touches the core, at the same time watching the needle. Study results, direction of current, etc., as before. (C) Suddenly withdraw M from the core. Is the current produced in the same direction as that from (B)? (D) Turn M end for end and repeat (B) and (C). (E) Repeat (C) and (D), moving magnet slowly. How does the strength of the current compare with that of Exp. 175? Are lines of force made to cut the turns of the coil? [Illustration: Fig. 137.] =EXPERIMENT 177. To find whether a current can be generated with a horseshoe magnet and a coil of wire having an iron core.= =431. Directions.= (A) Arrange the apparatus as in Exp. 176, but use the horseshoe magnet, H M, instead of the bar magnet. Fig. 137 shows the coil (No. 90) with one pole of H M held over the core. (B) Study the effect of quickly lowering and raising first one pole and then the other over the core, as with the bar magnet. Get clearly in mind the direction in which the induced current flows in each case. _=432. Induced Currents and Lines of Force.=_ In the experiments just given, it should be remembered that the permanent magnets are sending out thousands of lines of force from their N poles, and receiving them again at their S poles. As the magnet is pushed into the coil (Exp. 175), the lines of force not only cut through the turns of the coil, but the number of lines of force that cut the coil at any instant varies rapidly as the magnet is moved. Motion is necessary, with this arrangement, to make a change in the number of cutting lines of force. The current passes only while the magnet moves; and the direction of the current at any moment depends upon whether the number of lines of force is increasing or decreasing at that moment. (See § 438, 439.) [Illustration: Fig. 138.] =EXPERIMENT 178. To find whether a current can be generated with an electromagnet and a hollow coil of wire.= =433. Directions.= (A) The hollow coil (No. 90) should be joined to the astatic galvanoscope, as shown in Fig. 136. Instead of the bar magnet in Fig. 136, an electromagnet is to be used, and this should be joined in series with a cell and key, as shown in Fig. 138. The current from the cell will pass only when K is pressed. (B) Note from the winding which way the current must pass around the coil when the circuit is closed at K, and determine whether the lower end of the long iron core, L I C (No. 96) should be N or S. With the compass test the poles of the core to be sure you are right. (C) Quickly lower the end of L I C into the hollow coil (H, Fig. 136), the circuit being kept closed long enough to allow the needle to partially come to rest again. Withdraw L I C before you open the circuit. Explain action of needle. (D) Reverse the direction of the current through the electromagnet, by changing the connections, and repeat (C). Does any induced current pass through A G when the core is held still in the coil H, even though a current passes through coil E? [Illustration: Fig. 139.] =EXPERIMENT 179. To find whether a current can be generated with an electromagnet and a coil of wire having an iron core.= =434. Directions.= (A) Fig. 139 shows simply the arrangement of coils. Coil H (No. 90) with core, is joined to the galvanoscope as in Fig. 136. Coil E, with short core, should be joined to key and cell as shown in Fig. 138. (B) Keeping in mind the polarity of the lower end of core E, quickly lower it to the core of H, the circuit being kept closed for a few seconds. Does the needle remain deflected after the motion ceases? (C) Quickly raise E, the circuit being still closed, then open the circuit. Compare the directions taken by the induced currents in (B) and (C). _=435. Discussion of Exps. 178, 179.=_ This motion in straight lines is not suitable for producing currents strong enough for commercial purposes. In order to produce currents of considerable strength, the coils of wire have to be pushed past magnets with great speed. Special machines (see Dynamos) are constructed in which the coils are wound so that they can be given a rapid _rotary motion_ as they fly past strong electromagnets. In this way the coil can keep on passing the same magnets, in the same direction, as long as force is applied to the shaft that carries them. [Illustration: Fig. 140.] =EXPERIMENT 180. To study the effect of starting or stopping a current near a coil of wire or other closed circuit.= =436. Directions.= (A) Arrange as in Fig. 140. Place the two coils, H and E, on the same core, L I C. Connect E with the key and cell as before (Fig. 138). Connect H with the astatic galvanoscope, A G, as in Fig. 136. Keep the coils 2 or 3 feet from A G, so that the needle will not be affected by them. (B) Close the circuit at the key, watching the needle, then as soon as the needle regains its former position, open the circuit again. Compare the direction of the induced current in H with that of the current in E, (1) when the main circuit is closed, and (2) when it is opened. Is any current induced in H by a steady current in E? (See Transformers.) [Illustration: Fig. 141.] =EXPERIMENT 181. To study the effect of starting or stopping a current in a coil placed inside of another coil.= =437. Directions.= (A) Arrange as in Fig. 141. Join coil H with the astatic galvanoscope, A G. Place the small coil P (No. 98) with core, inside of H, and connect the ends of P with the key and cell, as shown. (B) Close the circuit at K; watch the needle, and as soon as it regains its position, open the circuit again. Compare the direction of the induced current in H with that of the inducing current in P, (1) when the inducing circuit is closed, and (2) when it is broken. (See Induction Coils.) _=438. Discussion of Exps. 180, 181.=_ When a current suddenly begins to flow through a coil, the effect upon a neighboring coil is the same as that produced by suddenly bringing a magnet near it; and when the current stops, the opposite effect is produced. We may consider that when the inducing circuit is closed, the lines of force shoot out through the turns of the outside coil. Upon opening the circuit the lines of force cease to exist; that is, we may imagine them drawn in again. [Illustration: Fig. 142.] _=439. Direction of Induced Current.=_ Fig. 142 shows the magnet on its way into the coil; the number of lines of force is increasing in the coil, and the induced current passes in an anti-clockwise direction when looking down into the coil along the lines of force. This produces an _indirect_ current. If a current from a cell were passed through the coil in the direction of this indirect current, the lower end of a bar of iron would become a S pole. (See § 428.) _=440. Laws of Induction.=_ (1) An increase in the number of lines of force that pass through a closed circuit produces an indirect induced current; while a decrease produces a direct one. (See § 428.) (2) The E. M. F. of the induced current is equal to the rate of increase or decrease in the number of lines of force that pass through the circuit. (3) A constant current produces no induced current, provided there is no motion. (4) Closing a circuit produces an indirect current. (5) Opening a circuit produces a direct current. (6) _Lenz's Law._ Induced currents have a direction that tends to stop the motion that produces them. _=441. Primary and Secondary Currents.=_ In the preceding experiments in induction, it must be kept in mind that the current from the cell did not pass through the galvanoscope. There were two entirely separate circuits, in no way connected. The _primary_ current comes from the cell, while the _secondary_ current is an induced one. [Illustration: Fig. 143.] =EXPERIMENT 182. To see what is meant by alternating currents.= =442. Directions.= (A) Arrange as in Fig. 143. Connect coil H with A G, as before. Place one pole of H M against the end of the core I C, hold H with one hand, and with the other quickly push the other pole of H M onto the core. This should produce a momentary current through A G, first in one direction, and then in the other. Let the needle come to rest. (B) Move H M back and forth upon the end of I C, changing its polarity rapidly. A minute's practice will enable you to slide the core from one pole of H M to the other and back again rapidly--3 complete vibrations per second being about right. The needle should be parallel to the coil of A G, and if properly done, the needle will be made to vibrate back and forth slightly at each change in the polarity of I C. _=443. Direct and Alternating Currents.=_ A current that flows steadily in one direction is said to be a _direct_ current. A cell gives a direct current when the circuit is closed. When the current passes in one direction for an instant, and then reverses immediately and flows in the opposite direction, it is said to _alternate_. The induced current which flowed through the galvanoscope in Exp. 182 was an alternating one. Currents of this class have great practical uses. _=444. Self-Induction; Extra Currents.=_ It has been shown that a magnetized coil can act through space and induce a current in a neighboring coil. The lines of force which reach out from an electromagnet will generate a current in any conductor which happens to be in the field, or which is moved across the lines. It is evident, then, since the lines of force from each turn of a coil cut all the other turns of the same coil, that each turn acts as a conductor placed in the field of every other turn. The instant a current begins to flow through a coil, there is an inverse current of self-induction started in the coil, which opposes the current in the cell. When the circuit is broken, this _extra current_, as it is also called, is a direct one and adds its strength to that of the current from the cell; as this takes place at the instant the circuit is broken, a bright spark is seen at the key, and this shows that the E. M. F. of this extra current is high. Practical uses are made of it. CHAPTER XXVI. THE PRODUCTION OF MOTION BY CURRENTS. _=445. Currents and Motion.=_ We have seen, in the experiments on induced currents, that a current of electricity can be generated by properly moving magnets near coils of wire. (See Dynamo-electric Machines.) Can we reverse this process? Can motion be produced by the electric current? =EXPERIMENTS 183-190. To study the production of motion by means of the electric current.= _Apparatus._ The support, including base, rod, and support wire, S W (Fig. 144.) Coils of wire (No. 89, 90); iron cores for coils; cell; key; connecting wires; compass; current reverser; bar magnet; horseshoe magnet. [Illustration: Fig. 144.] =EXPERIMENT 183. Motion produced with a hollow coil and a piece of iron.= =446. Directions.= (A) Arrange as in Fig. 144. Coil H (No. 90) is to be used as a pendulum, and can be supported by fastening a string to it, the upper end of which should be tied to S W. Connect the ends of H with K and D C. There will be a slight magnetic field about H as soon as the circuit is closed. (B) Hold I C near the end of the coil. Close the circuit for an instant. Is there any motion produced in H? While the motion will be slight, there should be enough to be noticed if the cell is strong. (C) Swing the suspended coil back and forth like a pendulum for a minute, until you get in mind the rapidity of its vibrations. Stop it, then repeat (B), closing and opening the circuit at regular intervals, so that the little impulses given by the attraction for I C will gradually cause H to vibrate. The wires leading from H should not drag upon the table. =EXPERIMENT 184. Motion with hollow coil and bar magnet.= =447. Directions.= (A) Substitute the bar magnet M (No. 97) for the iron of Exp. 183 (Fig. 144). Get clearly in mind the polarity of the coil from the way the current flows through it, then test it with the compass to find whether you are right. (B) Hold the N pole of M near the left-hand end of the coil, close the circuit for an instant and study results. (C) Reverse the magnet and repeat (B). Compare the results with those of Exp. 183. Try to make the coil vibrate. =EXPERIMENT 185. Motion with electromagnet and piece of iron.= =448. Directions.= (A) Arrange as described in Exp. 183, Fig. 144. Place a short core inside of the coil and repeat. (See § 446 for directions.) Why is the motion produced much larger than that given by a hollow coil? (B) The coil can gradually be made to swing through quite a little space by closing and opening the circuit regularly (§ 446, C). Could any use be made of such a motion, if it were on a large scale? Could it be made to run a machine? [Illustration: Fig. 145.] =EXPERIMENT 186. Motion with electromagnet and bar magnet.= =449. Directions.= (A) Arrange as in Fig. 145, the coil being suspended and connected as in Exp. 183 (Fig. 144). (B) Study the effect of closing the circuit when the N pole of M is held near the core of H. Reverse M, and repeat. [Illustration: Fig. 146.] =EXPERIMENT 187. Motion with electromagnet and horseshoe magnet.= =450. Directions.= (A) Arrange as in Fig. 146. The ends of H (No. 89) are joined to X and Y of the current reverser C R (No. 57). It is evident, then, that the direction of the current through H can be easily and rapidly reversed by C R. (See Exp. 103.) Either pole of the horseshoe magnet H M will attract I C when it is not magnetized. (B) Place the end of I C near the N pole of H M so that it will be attracted to it. You have learned that like poles repel each other, so press the lever of C R that will produce a N pole at the left-hand end of I C. The core I C should be repelled by the N pole of H M and be instantly attracted by its S pole. (C) Rapidly reverse the current and make I C jump back and forth from one pole to the other. The results of this experiment should be remembered, as they will aid in understanding motors. A core 1/4 in. in diameter can be placed in between the poles and be made to vibrate rapidly as the current is reversed. [Illustration: Fig. 147.] =EXPERIMENT 188. Motion with two electromagnets.= =451. Directions.= (A) Arrange as in Fig. 147. Join the two coils, H and E, in parallel. Connect their two outside ends O E to a metal plate A, and their inside ends I E to B. Join wires 1 and 6 to K, D C, A and B, as shown. When the circuit is closed at K, the current will pass along wire 1 and divide at A, entering E and H at the same time by wires 2 and 4 and returning through 3 and 5 to B, and thence to D C. (B) Close the circuit for an instant with wires arranged as in Fig. 147. Do the electromagnets attract or repel each other? Study out the direction in which the current passes around the coils, and see whether they _should_ attract or repel. (C) Change wire 4 to B, and wire 5 to A. The polarity of H, only, will be changed when this circuit is closed. Press the key for an instant and study the results. _=452. Discussion of Exps. 183-188.=_ From the results it is evident that motion can be produced with the aid of the electric current in many different ways. It can be produced at the ends of wires which simply reach across the room, or which reach miles from the source of the current. To get practical results for commercial purposes we require a proper source of current, proper conductors, and proper apparatus to convert the motions into useful work. The motions given to the parts of the apparatus in the previous experiments are not suitable for commercial purposes, as they are in straight lines. A rotary motion is needed to do good work; and when this is applied to a shaft, belts can be used to run all sorts of machinery. (See Electric Motors.) [Illustration: Fig. 148.] =EXPERIMENT 189. Rotary motion with a hollow coil of wire and a permanent magnet.= =453. Directions.= (A) Arrange as in Fig. 148. A key can be used instead of the reverser. The coil of the galvanoscope, G V, has a magnetic field about it when the circuit is closed. The needle has a permanent field. (B) Close the circuit for an instant, let the needle swing back past the zero mark, close the circuit again, etc., until the added impulses give the needle a complete turn. (C) Keep the needle turning on its axis by opening and closing the circuit at the proper time. With a little practice you can make it turn rapidly. (D) Reverse the motion of the needle. (See § 455.) [Illustration: Fig. 149.] =EXPERIMENT 190. Rotary motion with an electromagnet and a permanent magnet.= =454. Directions.= (A) Arrange as in Fig. 149. Place the compass a short distance from the end of the core of the coil H (No. 89). Close the circuit, and as soon as the needle gets part way around open it again, closing it at the proper time to give the needle a new impulse. The speed can be regulated, somewhat, by changing its distance from the core. A key may be used in place of a reverser. (B) Reverse the direction of rotation. _=455. Discussion of Exps. 189-190.=_ We have, in these experiments, the key to the action of electric motors. By properly opening and closing the circuit, the rotary motion can be kept up as long as current is supplied. If a small pulley were attached to the top of the compass-needle in Exp. 190, a tiny belt could be attached, and we should have a machine that could do, perhaps, a fly-power of work. (See Electric Motors.) CHAPTER XXVII. APPLICATIONS OF ELECTRICITY. _=456. Things Electricity Can Do.=_ Among the almost countless things that electricity can do are the following: It signals without wires. It drills rock, coal, and teeth. It cures diseases and kills criminals. It protects, heats, and ventilates houses. It photographs the bones of the human body. It rings church bells and plays church organs. It lights streets, cars, boats, mines, houses, etc. It pumps water, cooks food, and fans you while eating. It runs all sorts of machinery, elevators, cars, boats, and wagons. It sends messages with the telegraph, telephone, and search-light. It cuts cloth, irons clothes, washes dishes, blackens boots, welds metals, prints books, etc., etc. As this book deals almost exclusively with experiments, to be performed with simple, home-made apparatus, space cannot be given for a discussion of the many instruments and machines which make electricity a practical every-day thing. (See "Things A Boy Should Know About Electricity.") The principles upon which a few important instruments depend, however, will be given. [Illustration: Fig. 150.] =EXPERIMENT 191. To study the action of a simple "telegraph sounder."= =457. Directions.= (A) Arrange as in Fig. 150. The electromagnet is supported upon its base, as directed in § 407. Coil H, K, and D C are joined in series. The iron strip, I, can be held by the left hand, while K is worked with the right. (B) Press the key, closing the circuit for different lengths of time, and note that the _armature_, I, responds exactly to the motions at K. _=458. Discussion.=_ The downward click makes a distinct sound, and in regular instruments the armature is allowed to make an upward click, also. The time between the two clicks can be short or long to represent _dots_ or _dashes_, which, together with _spaces_, represent letters. (For telegraph alphabet, and complete directions for making and connecting a home-made telegraph line, see Apparatus Book.) [Illustration: Fig. 151.] _=459. Telegraph Line; Connections.=_ Fig. 151 shows complete connections for a home-made telegraph line. The capital letters are used for the right side, R, and small letters for the left side, L. Gravity cells, B and b, are used. The _sounders_ S and s, and the _keys_, K and k, are shown by a top view, or plan. The broad black lines of S and s represent the armatures, which are directly over the electromagnets. The keys have switches, E and e. The two stations, R and L, may be near each other or in different houses. The _return wire_, R W, passes from the copper of b to the zinc of B. This is important, as the cells must help each other; that is, they are in series. The _line wire_, L W, passes from one station to the other, and the return may be through a wire, R W, or through the earth; but for short lines a return wire is best. _=460. Operation of Line.=_ Suppose R (right) and L (left) have a line. Fig. 151 shows that R's switch, E, is open, while e is closed. The entire circuit, then, is broken at but one point. As soon as R presses his key, the circuit is closed, and the current from both cells rushes around from B through K, S, L W, s, k, b, R W and back to B. This makes the armatures of S and s come down with a click at the same time. (See Exp. 191.) As soon as the key is raised, the armatures raise, making the up-click. (See § 458.) As soon as R has finished, he closes his switch, E. L then opens e and answers R. Both E and e are closed when the line is not in use, so that either can open his switch at any time and call up the other. Closed circuit cells are used for such lines. On large lines the current from a dynamo is used. [Illustration: Fig. 152.] =EXPERIMENT 192. To study the action and use of the "relay" on telegraph lines.= =461. Directions.= (A) Arrange as in Fig. 152. Place K and D C at one end of the table to represent the sending station. At the other end of the table place E, which is the electromagnet of the relay, and H, the electromagnet of the sounder. Connect the ends of E with K and D C, L W being the line wire, and R W the return. In practice, the return is through the earth. The relay armature, R A, should vibrate towards E every time K is pressed. C is a piece of copper against which R A presses each time it is attracted by E, and this closes what is called the local circuit. Connect the poles of another battery, L B, with C and H, and the other end of coil H with R A. The sounder armature, S A, should be arranged as in Exp. 191. Small springs are shown on the two armatures, and these keep them away from the cores when the circuits are open. (B) Fasten the parts to a board, and study the connections and action of this home-made outfit. =462. The Relay= replaces the sounder in the line wire circuit, and its coils are usually wound with many turns of fine wire, so that a feeble current will move its nicely adjusted armature. Owing to the large resistance of long telegraph lines, the current is weak when it reaches a distant station, and not strong enough to work an ordinary sounder. The current passes back from the relay to the sending station through the earth. The relay armature acts as an automatic key to open and close the local circuit, which includes also a battery and sounder. The line current does not enter the sounder. (See "Things A Boy Should Know About Electricity.") [Illustration: Fig. 153.] =EXPERIMENT 193. To study the action of a two-pole telegraph instrument.= =463. Directions.= (A) Arrange as in Fig. 153. Connect the two coils to the connecting plates, as described in § 408. Join a strip of copper Cu with wire 2 leading from D C, and join the zinc of D C to M. The ends of wires 1 and 3 should be near Cu but they must not touch it. If Cu be slightly curved so that its ends are raised above the table, the ends of wires 1 and 3 may be put directly under the ends of Cu; each half of Cu can then be used as a key. Two armatures, A and B, should be held as shown. D C can be placed at one side, of course, its terminals being joined to M and Cu. (B) Press first one end and then the other of Cu, so that the current will pass through H or E at will. (C) Paste pieces of paper to the armatures, the left one being marked with a dot, and the other with a dash. The one who sends the message can make dots or dashes at the instrument by pressing the proper key. This form of instrument can be easily made by boys, and the messages are more easily read by the eye than by the ear, as in regular sounders. [Illustration: Fig. 154.] =EXPERIMENT 194. To study the action of a simple "single needle telegraph instrument."= =464. Directions.= (A) Arrange as in Fig. 154. Stick a pin on each side of the N pole of the galvanoscope-needle through the degree-card, so that the needle can make but part of a turn when the circuit is closed. (B) Touch one lever of the reverser C R, then the other, to see whether connections are right. The needle should be forced against one pin and then against the other. If motions to the left represent _dots_, and those to the right _dashes_, combinations of dots and dashes can be used for letters as in the "sounder" (Exp. 191). (C) Arrange the apparatus shown in Fig. 122 so that messages can be sent. [Illustration: Fig. 155.] =EXPERIMENT 195. To study the action of a simple automatic "contact breaker," or "current interrupter."= =465. Directions.= (A) Arrange as in Fig. 155. Slip a spring connector attached to wire 1 upon the iron strip I, a short distance from its end. Hold the left-hand end of I firmly in one hand, and with the other hold the connector on wire 2 just above that on 1. The right-hand end of I should be just above the core of H. (B) Allow the current to pass through the circuit by touching the two connectors together gently. Does the armature make one click, as in the telegraph sounder, or does it vibrate rapidly? (C) Try the connectors in various positions on I. _=466. Automatic Current Interrupters=_ are used on bells, buzzers, induction coils, etc. The principle upon which they work is shown in the above experiment (Fig. 155). The current, as it comes from the carbon of D C, is obliged to stop when it reaches I, unless the two connectors touch. As soon as the current passes, I is pulled down and away from the upper connector, and this breaks the circuit. I, being held firmly in the hand, immediately springs back to its former position, closing the circuit. The rapidity of the vibrations depends somewhat upon the position of the connectors upon I. In regular instruments, a platinum point is used where the circuit is broken; this stands the constant sparking at that point. [Illustration: Fig. 156.] =EXPERIMENT 196. To study the action of a simple "electric bell," or a "buzzer."= =467. Directions.= (A) Fig. 156 shows the circuit explained in Exp. 195, with a key or push-button put in, so that the circuit can be closed at a distance from the vibrating armature. (B) Have a friend work the key while you hold I and wires 1 and 2 as directed in Exp. 195. The circuit must not be broken at two places, of course, so begin by holding the two connectors together. The armature should vibrate rapidly each time K is pressed. _=468. Electric Bells and Buzzers=_ are very nearly alike in construction; in fact, you will have a buzzer by removing the bell from an ordinary electric bell. Buzzers are used in places where the loud sound of a bell would be objectionable. By placing a bell near the end of the vibrating armature (Fig. 156), so that the bell would be struck by it at each vibration, we should have an electric bell. By making the wires 1 and 3 long, the bell or buzzer can be worked at a distance. (See Apparatus Book, Chapter XV, for Home-made Bells and Buzzers.) [Illustration: Fig. 157.] =EXPERIMENT 197. To study the action of a simple telegraph "recorder."= =469. Directions.= (A) Cut from a tin box, or can, a piece of tin about 4 in. long and 1-1/2 in. wide. Bend this double to make two thicknesses. This will serve as an armature I (Fig. 157). Nail to one end of I a small spool, S, and into this put a short length of lead-pencil, P, which may be held firmly in S by wrapping a little paper around it. Connect the ends of coil H to a key and cell as in Fig. 156. (B) Hold or fasten I in place, and have a friend make dots and dashes at the key, while you draw a piece of paper past the end of P. A little adjusting will be necessary to get the pencil to write only while the circuit is closed. In regular machines all the parts are automatic. [Illustration: Fig. 158.] =EXPERIMENT 198. To study the action of a simple "annunciator."= =470. Directions.= (A) Arrange as in Fig. 158. Fasten the two electromagnets, H and E, to a board or a piece of stiff cardboard. They may be held in place by passing strings over them and through the board, tying on the other side. The ends of coils H and E should be joined to pieces of tin, A, B, C, by means of connectors. K and K are keys or push-buttons, which in real instruments are in different rooms. Two steel pens may be swung on pins a short distance from the ends of the cores, so that their lower ends will be attracted to the cores the instant the current passes through them. The residual magnetism should hold them against the cores until removed. Hairpins, nails, or needles can be used instead of pens. (B) Press first one K and then the other to see whether your connections are correct. _=471. Annunciators.=_ There are many forms of annunciators in use to indicate, in a hotel for example, a certain room when a bell rings at the office. If a bell be included in the circuit between D C and A in Fig. 158, it will ring each time a key is pushed. This will call attention to the fact that some one has rung, and the annunciator will show the location of the special call. Large instruments are made with hundreds of electromagnets, each one answering to a special room. The instrument should be set, of course, after each call. A nail or screw wound with insulated wire can be used for the electromagnets of a home-made annunciator. =EXPERIMENT 199. To study the shocking effects of the "extra current."= =472. Directions.= (A) Use the two electromagnets joined to the connecting plates (Fig. 132), to generate a self-induced or extra current. Connect R of Fig. 132 with the zinc of a dry cell, and between L and the carbon of the cell place a key; in other words, join the electromagnets, cell, and key in series. Two good cells in series can be used to advantage. (B) Wet the ends of two fingers of the left hand, press one upon L and the other on R, thus making a shunt with your hand. With the right hand work the key rapidly. If the current is strong enough you should feel a slight shock in the fingers each time the circuit is broken. The extra current (§ 444) causes the shock as it shoots through the fingers. (C) If you have electric bells or telegraph sounders use them for this experiment. _=473. Induction Coils=_ are instruments for producing induced currents of high E. M. F. The apparatus shown in Fig. 141 forms a simple induction coil. The _primary_ coil is made of coarser wire and has less turns of wire than the _secondary_ coil. The current in the primary circuit is usually interrupted by an _automatic interrupter_ (Exp. 195), thus producing an alternating current in the secondary coil, the voltage of which depends upon the relative number of turns in the two coils. Induction coils are used in telephone work, for medical purposes, for X-ray work, etc., etc. (For Home-made Induction Coils see Apparatus Book, Chapter XI.) [Illustration: Fig. 159.] =474. Action of Induction Coils.= Fig. 159 shows a top view of one of the home-made induction coils described, in full, in the Apparatus Book. Wires 5 and 6 are the ends of the primary coil, while wires 7 and 8 are the terminals of the secondary coil. The battery wires should be joined to binding-posts W and X, and the handles to Y and Z. Fig. 160 shows the details of the automatic interrupter which is placed in the primary circuit. [Illustration: Fig. 160.] If the current enters at W, it will pass through the primary coil and out at X, after going through 5, R, F, S I, B, E and C. The instant the current passes, the bolt becomes magnetized; this attracts A, which pulls B away from the end of S I, thus automatically opening the circuit. B at once springs back to its former position against S I, as A is no longer attracted; the circuit being closed, the operation is rapidly repeated. (For commercial forms and uses of induction coils see "Things A Boy Should Know About Electricity.") _=475. Transformers=_, like induction coils, are instruments for changing the E. M. F. and strength of currents. There is very little loss of energy in well-made transformers. They consist of two coils of wire on the same core; in fact, an induction coil may be considered a transformer. If the secondary coil has 100 times as many turns of wire as the primary, a current with an E. M. F. of 100 volts can be taken from the secondary coil, when the E. M. F. of the current passing through the primary is 1 volt; but the _strength_ (amperes) of the secondary current will be but one-hundredth that of the primary current. By using the coil of fine wire as the primary, the E. M. F. of the current that comes from the other coil will be but one-hundredth that in the fine coil. It will have 100 times its strength, however. Continuous currents from cells or dynamos must be interrupted, as in induction coils, to be transformed from one E. M. F. to another. Transformers are now largely used in lighting and power circuits, etc. (See "Things A Boy Should Know About Electricity.") _=476. The Dynamo.=_ We saw in the Exps. of Chapter XXV. that currents of electricity can be generated in a coil of wire (closed circuit) by rapidly moving it through the field of a magnet. As shown by the experiments, this can be accomplished in many ways. The dynamo is a machine for doing this on a large scale, the coils being given a rotary motion in a very strong magnetic field; and as the number of lines of force that cut the coil is constantly changing, there is a current in the coil as long as power is applied, and this current is led from the machine by proper devices. _The dynamo is a machine for converting mechanical energy into an electric current, through electromagnetic induction._ If a loop of wire (Fig. 161) be so arranged on bearings at its ends that it can be made to revolve, a current will flow through it in one direction during one-half of the revolution, and in the opposite direction during the other half, it being insulated from all external conductors. Such a current inside of the machine would be of no value; it must be led out to external conductors. Some sort of sliding contact is necessary to connect a revolving conductor with a stationary one. [Illustration: Fig. 161.] [Illustration: Fig. 162.] Fig. 162 shows the ends of a coil joined to two rings, X, Y, which are insulated from each other, and which rotate with the coil. Two stationary pieces of carbon, A, B, called _brushes_, press against the rings, and to these are joined wires which complete the circuit, and which lead out where the current can do work. The arrows show the direction of the current during one-half of a revolution. The rings form a _collector_, and this arrangement gives an alternating current. [Illustration: Fig. 163.] In Fig. 163 the ends of the coil are joined to the two halves of a cylinder. These halves, X and Y, are insulated from each other and from the axis. The current flows from X onto the brush A, through some external circuit where it does work, and thence back through brush B onto Y. By the time that Y gets around to A the direction of the current in the loop has reversed, so that it passes towards Y; but it still enters the outside circuit through A because Y is then in contact with A. This device is called a _commutator_, and it allows a constant or direct current to leave the machine. In regular machines there are many loops of wire and several segments to the commutator. The rotating coils are wound upon an iron core, so that the lines of force, in passing from one pole to the other, will meet with as little resistance as possible. The coils, core, and commutator, taken together, are called the _armature_. The magnets which furnish the field are called the _field-magnets_. These are electromagnets, the current from the dynamo, or a part of it, being used to excite them. There are many forms of dynamos, and many ways of winding the armature and field-magnets, but space will not permit a discussion of them here. (See "Things a Boy Should Know About Electricity.") _=477. The Electric Motor.=_ Experiments have shown that motion can be produced by the electric current in many ways. The galvanoscope may be considered a tiny motor. _An electric motor is a machine for transforming electric energy into mechanical power._ While the electric motor is similar in construction to the dynamo, it is opposite to it in action. Motors receive current and produce motion. The motion is a rotary one, the power being applied to other machines by means of belts or gears. [Illustration: Fig. 164.] =EXPERIMENT 200. To study the action of the telephone.= =478. Directions.= (A) Join the ends of coil H (Fig. 164) to the astatic galvanoscope. Move magnet M back and forth in front of the soft iron core, while H is held in position. Watch the needle. Imagine that vibrations in the air caused by the voice are strong enough to give M a slight motion to and fro, and you can see how a current would be sent through the galvanoscope by speaking against M. _=479. The Telephone=_ is an instrument for reproducing sounds at a distance, and electricity is the agent by which this is generally accomplished. The part spoken to is called the _transmitter_, and the part which gives the sound out again is called the _receiver_. Sound itself does not pass over the line. Although the same apparatus may be used for both transmitter and receiver, they are generally different in construction. [Illustration: Fig. 165.] _=480. The Bell or Magneto-transmitter=_ generates its own current, and is, strictly speaking, a dynamo that is run by the voice. You have seen, by experiments, that a current can be generated in a coil of wire by moving a magnet back and forth in front of its soft iron core. In the telephone this process is reversed, soft iron in the shape of a thin disc (D, Fig. 165) being made to vibrate by the voice immediately in front of a coil having a permanent magnet, M, for a core. The soft iron diaphragm is fixed near, but it does not touch the magnet. The coil consists of many turns of fine insulated wire. The current generated is an alternating one and exceedingly feeble; in fact, it can not be detected by a galvanoscope. _=481. The Receiver=_ has the same construction as the bell transmitter, and receives the currents from the line. As the diaphragm is always attracted by the magnet, it is under a constant strain. This strain is increased when a current passes through the coil in a direction that adds strength to the magnet, and decreased when the current weakens the magnet. When the current through the coil is always in the same direction, but varies in strength, the diaphragm will vibrate on account of the varying pull upon it. [Illustration: Fig. 166.] When the current through the coil is an alternating one, the same result is obtained, as the magnet gets weaker and stronger many times per minute. Fig. 166 shows two bell instruments joined, either being used as the transmitter and the other as the receiver. _=482. The Carbon Transmitter=_ does not in itself generate a current like the magneto-transmitter; it merely produces changes in the strength of a current that flows through it, and that comes from some outside source. In Fig. 167, X and Y are two carbon buttons, X being attached to the diaphragm, D. Button Y presses gently against X. When D is caused to vibrate by the voice, X is made to press more or less against Y, and this allows more or less current to pass through the circuit, in which also is the receiver, R. This direct undulating current changes the pull upon the diaphragm of R, causing it to vibrate and reproduce the original sounds spoken into the transmitter. [Illustration: Fig. 167.] _=483. Induction Coils in Telephone Work.=_ As the resistance of telephone lines is large, a current with a fairly high E. M. F. is desired. While the current from one or two cells is sufficient to work the transmitter, it is not strong enough to force its way over a long line. To get around this difficulty an induction coil is used to transform the battery current, that flows through the transmitter and primary coil, into a current with a high E. M. F. that can go into the main line and force its way to a distant receiver. The battery current in the primary coil is undulating, but always in the same direction, the magnetic field around the core getting weaker and stronger. This causes an alternating current in the secondary coil and main line. [Illustration: Fig. 168.] Fig. 168 shows the two coils, P, S, of the induction coil. The primary, P, is joined in series with a cell and transmitter. The secondary coil, S, is joined to the receiver. One end of S can be grounded, the current completing the circuit through the earth and into the receiver through another wire entering the earth. There are many forms of transmitters. (See "Things a Boy Should Know About Electricity.") _=484. Electric Lighting and Heating.=_ Whenever resistance is offered to the electric current, heat is produced. By proper appliances, the heat of resistance can be applied just where it is needed, and many commercial processes depend upon electricity for their success. Dynamos are used to generate currents for lighting and heating purposes. There are two great systems of lighting, the one by _arc_ lamps and the other by _incandescent_ lamps. (See "Things a Boy Should Know About Electricity.") _=485. Arc Lamps=_ produce a light when a current passes from one carbon rod to the other across an air-space. As the current starts through the lamp, the ends of the carbons touch, and the imperfect contact causes resistance enough to heat the ends red-hot. They are then automatically separated, and the current passes from one to the other, causing the "arc." The resistance of the air-space is reduced by the intensely heated vapor and flying particles of carbon. _=486. The Incandescent Lamp=_ consists of a glass bulb, in which is a vacuum, and the light is caused by the passage of a current through a thin fibre of vegetable carbon, enclosed in the vacuum. The fibre would burn instantly if allowed to come in contact with the air. The fibres have a high resistance, and are easily heated to incandescence. CHAPTER XXVIII. WIRE TABLES. _Copper Wire Tables_ are very convenient, and a necessity when working electrical examples. The tables here given are taken from a dealer's catalogue, and will be found sufficiently accurate for ordinary work. _Explanation of Tables._ In the _first_ column are given the sizes of wires by numbers. The B & S or American gauge is used. In the table below is given a comparison between the B & S and the Birmingham gauges. The _second column_ gives the diameters of wires. The diameter of No. 36 wire is 5 thousandths of an inch; the diameter of No. 24 wire is a little over 20 thousandths or 2 hundredths of an inch. The _third column_ contains what is called circular mils, a mil being a thousandth of an inch. The figures in this column are obtained by squaring those in the second; thus, for No. 36 wire, 5 × 5 = 25. This column is useful when working examples where the squares of the diameters are wanted. The rest of the table explains itself. The table at the bottom gives a comparison between the fractional and decimal parts of an inch. Space can not be given here for a series of examples showing the many uses of this table. (See "Elementary Electrical Examples.") COPPER WIRE TABLES. (Based on the B. A. Unit.) =====+=======+=========+=======+===================================+ Gauge| DIAM- |Sectional|Capac- | OHMS | | ETER. | AREA | ity. | | -----+-------+---------+-------+-----------+----------+------------+ B.&S.| In | In |In Amp-| Per | Per | Per | No. |1000ths|Circular | eres. | 1,000 | Mile. | Pound. | | | Mils. | | feet. | | | -----+-------+---------+-------+-----------+----------+------------+ 0000|.460 |211600. | 312. | .04906| .25903| .000077| 000|.40964 |167805. | 262. | .06186| .32664| .00012 | 00|.3648 |133079. | 220. | .07801| .41187| .00019 | 0|.32486 |105534. | 185. | .09831| .51909| .00031 | 1|.2893 | 83694. | 156. | .12404| .65490| .00049 | 2|.25763 | 66373. | 131. | .15640| .8258 | .00078 | 3|.22942 | 52634. | 110. | .19723| 1.0414 | .00125 | 4|.20431 | 41743. | 92.3 | .24869| 1.313 | .00198 | 5|.18194 | 33102. | 77.6 | .31361| 1.655 | .00314 | 6|.16202 | 26251. | 65.2 | .39546| 2.088 | .00499 | 7|.14428 | 20817. | 54.8 | .49871| 2.633 | .00792 | 8|.12849 | 16510. | 46.1 | .6529 | 3.3 | .0125 | 9|.11443 | 13094. | 38.7 | .7892 | 4.1 | .0197 | 10|.10189 | 10382. | 32.5 | .8441 | 4.4 | .0270 | 11|.090742| 8234. | 27.3 | 1.254 | 6.4 | .0501 | 12|.080808| 6530. | 23. | 1.580 | 8.3 | .079 | 13|.071961| 5178. | 19.3 | 1.995 | 10.4 | .127 | 14|.064084| 4107. | 16.2 | 2.504 | 13.2 | .200 | 15|.057068| 3257. | 13.6 | 3.172 | 16.7 | .320 | 16|.05082 | 2583. | 11.5 | 4.001 | 23. | .512 | 17|.045257| 2048. | 9.6 | 5.04 | 26. | .811 | 18|.040303| 1624. | 8.1 | 6.36 | 33. | 1.29 | 19|.03589 | 1288. | .... | 8.25 | 43. | 2.11 | 20|.031961| 1021. | .... | 10.12 | 53. | 3.27 | 21|.028462| 810. | .... | 12.76 | 68. | 5.20 | 22|.025347| 642. | .... | 16.25 | 85. | 8.35 | 23|.022571| 509. | .... | 20.30 | 108. | 13.3 | 24|.0201 | 404. | .... | 25.60 | 135. | 20.9 | 25|.0179 | 320. | .... | 32.2 | 170. | 33.2 | 26|.01594 | 254. | .... | 40.7 | 214. | 52.9 | 27|.014195| 201. | .... | 51.3 | 270. | 84.2 | 28|.012641| 159.8 | .... | 64.8 | 343. | 134. | 29|.011257| 126.7 | .... | 81.6 | 482. | 213. | 30|.010025| 100.5 | .... | 103. | 538. | 338. | 31|.008928| 79.7 | .... | 130. | 685. | 539. | 32|.00795 | 63. | .... | 164. | 865. | 856. | 33|.00708 | 50.1 | .... | 206. |1033. | 1357. | 34|.006304| 39.74| .... | 260. |1389. | 2166. | 35|.005614| 31.5 | .... | 328. |1820. | 3521. | 36|.005 | 25. | .... | 414. |2200. | 5469. | 37|.004453| 19.8 | .... | 523. |2765. | 8742. | 38|.003965| 15.72| .... | 660. |3486. |13772. | 39|.003531| 12.47| .... | 832. |4395. |21896. | 40|.003144| 9.88| .... | 1049 |5542. |34823. | -----+-------+---------+-------+-----------+----------+------------+ =====+=======================+======================== Gauge| FEET. | POUNDS. | | -----+-----------+-----------+-----------+------------ B.&S.| Per | Per | Per | Per No. | Pound. | Ohm. |1,000 feet.| Ohm. -----+-----------+-----------+-----------+------------ 0000| 1.56122|20497.7 | 640.51 |12987. 000| 1.9687 |16255.27 | 507.95 | 8333. 00| 2.4824 |12891.37 | 402.83 | 5263. 0| 3.1303 |10223.08 | 319.45 | 3225. 1| 3.94714| 8107.49 | 253.34 | 2041. 2| 4.97722| 6429.58 | 200.91 | 1282. 3| 6.2765 | 5098.61 | 159.32 | 800. 4| 7.9141 | 4043.6 | 126.35 | 505. 5| 9.97983| 3206.61 | 100.20 | 318. 6| 12.5847 | 2542.89 | 79.462 | 200. 7| 15.8696 | 2015.51 | 63.013 | 126. 8| 20.0097 | 1599.3 | 49.976 | 80. 9| 25.229 | 1268.44 | 39.636 | 50. 10| 31.8212 | 1055.66 | 31.426 | 37. 11| 40.1202 | 797.649 | 24.924 | 20. 12| 50.5906 | 632.555 | 19.766 | 12.65 13| 63.7948 | 501.63 | 15.674 | 7.87 14| 80.4415 | 397.822 | 12.435 | 5.00 15| 101.4365 | 315.482 | 9.859 | 3.12 16| 127.12 | 250.184 | 7.819 | 1.95 17| 161.29 | 198.409 | 6.199 | 1.23 18| 203.374 | 157.35 | 4.916 | .775 19| 256.468 | 124.777 | 3.899 | .473 20| 323.399 | 98.9533 | 3.094 | .305 21| 407.815 | 78.473 | 2.452 | .192 22| 514.193 | 62.236 | 1.945 | .119 23| 648.452 | 49.3504 | 1.542 | .075 24| 817.688 | 39.1365 | 1.223 | .047 25| 1031.038 | 31.0381 | .9699 | .030 26| 1300.180 | 24.6131 | .7692 | .0187 27| 1639.49 | 19.5191 | .6099 | .0118 28| 2067.364 | 15.4793 | .4837 | .0074 29| 2606.959 | 12.2854 | .3835 | .0047 30| 3287.084 | 9.7355 | .3002 | .0029 31| 4414.49 | 7.72143| .2413 | .0018 32| 5226.915 | 6.12243| .1913 | .0011 33| 6590.41 | 4.85575| .1517 | .00076 34| 8312.8 | 3.84966| .1204 | .00046 35|10481.77 | 3.05305| .0956 | .00028 36|13214.16 | 2.4217 | .0757 | .00018 37|16659.97 | 1.92086| .06003| .00011 38|21013.25 | 1.52292| .04758| .00007 39|26496.237 | 1.20777| .03755| .00004 40|33420.63 | 0.97984| .02992| .000029 -----+-----------+-----------+-----------+------------ Comparative Table of the Fractional and Decimal Parts of an Inch. +-----------------+ | 1/64 = .015625 | | 1/32 = .031250 | | 3/64 = .046875 | | 1/16 = .062500 | | 5/64 = .078125 | | 3/32 = .093750 | | 7/64 = .109375 | | 1/8 = .125000 | | 9/64 = .140625 | | 5/32 = .156250 | | 11/64 = .171875 | | 3/16 = .187500 | | 13/64 = .203125 | | 7/32 = .218750 | | 15/64 = .234375 | | 1/4 = .250000 | | 17/64 = .265625 | | 9/32 = .281250 | | 19/64 = .296875 | | 5/16 = .312500 | | 21/64 = .328125 | | 11/32 = .343750 | | 23/64 = .359375 | | 3/8 = .375000 | | 25/64 = .390625 | | 13/32 = .406250 | | 27/64 = .421875 | | 7/16 = .437500 | | 29/64 = .453125 | | 15/32 = .468750 | | 31/64 = .484375 | | 1/2 = .500000 | +-----------------+ Comparative Table of B. and S. and B. W. Gauges in Decimal Parts of an Inch. +------------+--------------+-------------+ |Birmingham | American | No. of | |Wire Gauge. | (B. and S.) | Wire Gauge. | | | Wire Gauge. | | +------------+--------------+-------------+ | 0000 | .46 | .454 | | 000 | .40964 | .425 | | 00 | .3648 | .38 | | 0 | .32486 | .34 | | 1 | .2893 | .3 | | 2 | .25763 | .284 | | 3 | .22942 | .259 | | 4 | .20431 | .238 | | 5 | .18194 | .22 | | 6 | .16202 | .203 | | 7 | .14428 | .18 | | 8 | .12849 | .165 | | 9 | .11443 | .148 | | 10 | .10189 | .134 | | 11 | .090742 | .12 | | 12 | .080808 | .109 | | 13 | .071961 | .095 | | 14 | .064084 | .083 | | 15 | .057068 | .072 | | 16 | .05082 | .065 | | 17 | .045257 | .058 | | 18 | .040303 | .049 | | 19 | .03589 | .042 | | 20 | .031961 | .035 | | 21 | .028468 | .032 | | 22 | .025347 | .028 | | 23 | .022571 | .025 | | 24 | .0201 | .022 | | 25 | .0179 | .02 | | 26 | .01594 | .018 | | 27 | .014195 | .016 | | 28 | .012641 | .014 | | 29 | .011257 | .013 | | 30 | .010025 | .012 | | 31 | .008928 | .01 | | 32 | .00795 | .009 | | 33 | .00708 | .008 | | 34 | .006304 | .007 | | 35 | .005614 | .005 | | 36 | .005 | .004 | | 37 | .004453 | | | 38 | .003965 | | | 39 | .003531 | | | 40 | .003114 | | +------------+--------------+-------------+ LIST OF APPARATUS FOR The Study of Elementary Electricity and Magnetism by Experiment. The =100= pieces of apparatus in the following list are referred to, by number, in the experiments contained in "The Study of Elementary Electricity and Magnetism by Experiment." This list is furnished to give those who wish to make their own apparatus an idea of the approximate size, etc., of the various articles used. The author is preparing a price catalogue of the articles included in this list, and of odds and ends needed in the construction of simple, home-made apparatus. =No. 1.= A package of 25 steel sewing-needles. To be suitable for experiments in magnetism, these should be of good, hard steel, and not too thick. =No. 2.= A flat cork, about 1 in. in diameter and 3/8 in. thick. =No. 3.= A candle for annealing steel. =No. 4-15.= One dozen assorted annealed iron wires, from 1 in. to 6 in. in length. The iron should be very soft. =No. 16.= One English horseshoe magnet, 2-1/2 in. long, best quality. =No. 17.= A small box of iron filings from soft iron. =No. 18.= A compass (Fig. 5). The needle swings very freely; it is enclosed in a wooden pill box, the cover of which forms the support. =No. 19, 20.= Two soft steel wire nails, 2 in. long. =No. 21, 22.= Two pieces of spring steel, about 3 in. long and 3/8 in. wide, to be magnetized by the student and used as bar magnets. =No. 23.= An iron ring, or washer, about 7/8 in. in diameter. =No. 24.= A sifter for iron filings. This consists of a pasteboard pill box: Prick holes through the bottom with a pin. =No. 25.= A thin, flexible piece of spring steel, about 3 in. long and 1/8 in. wide. =No. 26, 27.= Two ebonite sheets (E S, Fig. 34), each 4 in. square. These are made with a special surface. They are very much better than the ordinary smooth ebonite. =No. 28.= One ebonite rod (E R, Fig. 34), 3-1/2 in. long, with special surface. =No. 29.= One ebonite rod, 1-3/4 in. long, with special surface, used to support the insulating table, No. 43 (I T, Fig. 32). =No. 30.= One piece of flannel cloth, 7 in. square. =No. 31.= Six sheets of tissue-paper, each 4 in. square. =No. 32.= A few feet of white cotton thread. =No. 33.= A few feet of black silk thread. =No. 34.= One support base (S B, Fig. 56). This is of thin wood, about 3-3/4 in. by 6-1/2 in., to one end of which is fastened a spool for holding the support rod (No. 35). =No. 35.= One support rod (S R, Fig. 56), 7 in. long and 5/16 in. in diameter. This rod has a hole in each end. The small hole is for holding the support wire (No. 36); the large hole is for the ebonite rod (No. 29). =No. 36.= One support wire (S W, Fig. 144). =No. 37.= One wire swing (W S, Fig. 29). =No. 38.= One sheet of glass, 4 in. square. =No. 39.= One bent hairpin (H P, Fig. 32). =No. 40.= Bottom of flat box (B F B, Fig. 32), 3-5/8 in. in diameter. =No. 41.= Top of flat box (T F B, Fig. 33). =No. 42.= One electrophorus cover (E C, Fig. 34), 3-5/8 in. in diameter. This has rounded edges, and a small tube is riveted into the top of it to hold the insulating handle, E R. =No. 43.= One insulating table (I T, Fig. 32). This is made the same as No. 42, and is supported by No. 29. =No. 44.= One insulated copper wire, 2-1/2 feet long. =No. 45.= One rubber band (R B, Fig. 33). =No. 46.= Six bent wire clamps (B C, Fig. 37). =No. 47.= One tin box conductor (T B, Fig. 42). This cylindrical conductor is about the size of an ordinary baking powder box. =No. 48.= One hairpin discharger for the condenser. =No. 49.= Two sheets of aluminum-leaf for the leaf electroscope (Fig. 57) and other experiments. =No. 50.= One bent wire (H P, Fig. 57) used in connection with the leaf electroscope. =No. 51.= A dry cell, ordinary size about 7 in. high and 2-1/2 in. in diameter. =No. 52.= Enough mercury to amalgamate battery zincs. A wooden pill box containing about half a thimbleful will do. =No. 53.= A coil containing 25 feet of No. 24 insulated copper wire for connections. =No. 54.= One dozen spring connectors (Fig. 61) for making connections. These are made of brass, nickel plated, and do not affect the compass-needle. =No. 55.= A telegraph key (Fig. 68) without switch. The metal straps are made of aluminum; they are 1/2 in. wide, and are fastened to a neat wooden base. =No. 56.= Three metal plates, each about 2 in. by 3/4 in., on which spring connectors (No. 54) are to be pushed in order to join two wires. =No. 57.= A current reverser (Fig. 69). The straps are made of aluminum and are fastened to a neat wooden base. =No. 58.= A galvanoscope (Fig. 72) including a degree-card (No. 99). The cardboard coil-support, C S, is 5 × 6-1/4 in., and the hole in it is 3-3/8 in. in diameter. The coil is 4-1/4 in. in diameter, made of No. 24 insulated copper wire. =No. 59.= An astatic galvanoscope (Fig. 77). The whole may be taken apart and mailed in the containing box, B, which is 4-3/8 × 3-1/8 × 1 in. The coil is made of No. 31 wire, and has a resistance of about 5 ohms. Spring connectors are used to join a wire to the apparatus by pushing the connectors into the tubular binding-posts, L and R. =No. 60-63.= Four strips of sheet zinc, 4 in. by 1/2 in., not amalgamated. =No. 64.= A carbon rod, 4 in. long (Fig. 81). =No. 65, 66.= Two glass tumblers (Fig. 81). =No. 67, 68.= Two strips of sheet copper, 4 in. by 1/2 in. (Fig. 85). =No. 69.= One galvanized iron nail. =No. 70, 71.= Two wooden cross-pieces (Fig. 85). =No. 72.= One dozen brass screws, 5/8 in. long, size No. 5, with round heads. =No. 73.= A porous cup (P C, Fig. 87) that will stand inside of the tumblers (No. 65). =No. 74.= A zinc rod, about 3/8 in. in diameter, like those used in Leclanché cells. =No. 75.= A sheet copper plate for the two-fluid cell (C, Fig. 87). This is 2 in. wide; it nearly surrounds the porous cup, and is supported upon the edge of the tumbler by a narrow strip, A, with which connections are made by spring connectors (No. 54). =No. 76.= One strip of sheet iron, 4 in. by 1/2 in. =No. 77, 78.= Two strips of sheet lead, 4 in. by 1/2 in. =No. 79.= A resistance coil (Fig. 94). The coil is made of No. 24 insulated copper wire; it has a resistance of 2 ohms (nearly) and is fastened to a cardboard base. It is so arranged that either one or two ohms can be used at will. =No. 80.= A Wheatstone's bridge (Fig. 103), including a scale (No. 100). The aluminum straps, 1, 2, 3, are fastened to a neat wooden base, 10 in. long by 2 in. wide. A No. 28 German-silver wire is used for the bridge. =No. 81.= A piece of No. 30 uncovered German-silver wire, 2.1 meters long, used for resistance (Fig. 96). =No. 82.= A piece of No. 28 uncovered German-silver wire, 2.1 meters long. =No. 83-85.= Three plate binding-posts, consisting of bent straps of sheet aluminum (X, Y, Z, Fig. 96). =No. 86.= Two ounces of copper sulphate, commonly called bluestone. The crystals may be kept in a large wooden pill box. =No. 87.= One dozen copper washers. =No. 88.= One combination rule, 1 ft. long, marked with English and metric systems. =No. 89.= A hollow coil of No. 24 insulated copper wire (Fig. 130). The spool, on which the wire is wound, has a hole for a five-sixteenths inch core. It is turned down thin, so that the wire is near the core. The coil is about 1-1/8 in. long and 1 in. in diameter. Spring connectors are joined to the ends of the coil. =No. 90.= A hollow coil of No. 25 insulated copper wire, similar to No. 89, with spring connectors attached to its ends. =No. 91.= Carbon rod for electroplating. =No. 92, 93.= Two soft iron cores, with screws (I C, Fig. 130). These cores are 5/16 in. in diameter, and have a threaded hole in one end for fastening them to No. 94. =No. 94.= A tin box with three holes punched in its top (Fig. 132). This serves as a base, as well as a yoke, for the two electromagnets, A, B, shown in plan. =No. 95.= Combination connecting plates (Fig. 132). Three aluminum straps are fastened to a wooden base. They are turned up at their ends so that spring connectors can be easily pushed upon them. =No. 96.= One long iron core (L I C, Fig. 140). This is of soft iron, 5/16 in. in diameter, and long enough to pass through both coils (No. 89, 90). =No. 97.= Bar magnet, about 4 in. long and 5/16 in. in diameter. =No. 98.= Coil of insulated wire wound on a soft iron core, to act as a primary coil for induction experiments. This coil fits inside of the hollow coils (Nos. 89, 90). =No. 99.= A printed degree-card for the galvanoscope (No. 58). This is printed on stiff cardboard, about 3 in. in diameter. =No. 100.= A printed scale for the Wheatstone's bridge (No. 80). This is printed on stiff paper. The scale is 8 in. long, and is divided into 10 large divisions, each of which is subdivided into 10 parts, thus making 100 parts in all. INDEX. Numbers refer to paragraphs. See Table of Contents for the various experiments. Abreast, arrangement of cells, 365. Accumulators. (See storage cells.) Action, local, 273. Air, as insulator, 144, _a_. Alternating currents, 443. Amalgamating, 257, 274. Amber, 107. Ammeter, 353. Ampere, the, 351, 357. Ampere's rule, 386. Annealing, 6. Annunciators, 471. Anode, 373, 378. Applications of electricity, Chap. XXVII. Arc lamp, 485. Arrangement, of cells, 363 to 368. Armature, the, 11, 78, 476. Astatic needles, 251, 253, 254; galvanoscope, 252, 256. Atmospheric electricity, Chap. XIII., 217; causes of, 221. Attraction, mutual, 111; and repulsion, laws of magnetic, 29; electric, laws of, 121. Aurora borealis, 223. Batteries, Chap. XV.; storage, 382. Bell, electric, 468. Bell telephone, 480. Bichromate cell, 289. Bound electrification, 162, 191. Breaking a magnet, 51. Bridge, Wheatstone's, 324 to 330. Brushes, 476. Buzzers, electric, 468. Cable, submarine, as condenser, 182. Capacity, inductive, 169; electrical, 176, 178. Carbon, transmitter, 482; electroscope, 114. Cathode, 373. Cell, galvanic, Chap. XV.; arrangement of, 363, 364, 365, 368; chemical action in, 270, 271; direction of current in, 268; local action in, 273; open and closed circuit, 286; polarization of, 278; poles of, 269; simple, 275; secondary, 382; single-fluid, 275; two-fluid, 281, 285; various galvanic, 286 to 291. Charge, in condenser, 195; residual of condensers, 197. Charging conductors, Chap. VIII. Chemical action, 369. Chemical effects of current, Chap. XXI. Circuit, electric, 266; divided, 293; short, 295. Coercive force, 44, 46. Coils, 390; induction, 473, 474; method of joining, 408; polarity of, 392; resistance, 309; simple resistance, 310. Commutator, 476. Compass, 26; our, 32; needle, 243, 249. Compound magnets, 73. Condensation of electrification, Chap. X., 178. Condensers, 178; action of, 186, 191; induction coil, 181; submarine cables, 182. Conductive discharge, 149, 184. Conductors, 126, 129, 133; hollow and solid, 153; and insulators, relation between, 133; and non-conductors, 312. Connections, electrical, 226 to 230. Contact breaker, Exp. 195; § 466. Convective discharge, 149. Copper sulphate solution, 283. Cores, of electromagnets, 397. Coulomb, the, 354. Current electricity, Part III. Current, 144, _a_, 264; detectors, 232, 239; direction of in cell, 268; direct and alternating, 443; extra, 444; interrupters, 466; primary and secondary, 441; measurement of, 352; reverser, 235, 237; strength of, Chap. XX., 350, 358, 362 to 365; unit of, 351. Daniell cell, 290. Declination, 84. Depolarizers, 280, 282. Detectors, current, 232, 239. Diamagnetic bodies, 15. Dielectric, 184, 191, 195. Dielectrics, 166. Dip, 86. Direct currents, 428, 443. Dischargers, 188. Discharges, kinds of, 149. Divided circuits, 293, 323. Dry cells, 288. Dynamo, 435, 476. Earth's magnetism, 83, 92, 93. Electric, bells, 468; chime, 193; circuit, 266, Chap. XVI.; current, 144, _a_, 264; density, 155; field, 156; horse-power, 355; lighting, 484; machines, static, 216; motor, 477; polarization, 159; resistance, Chap. XVIII.; wind, 155. Electricity, static, Part II.; Current, Part III.; Applications of, Chap. XXVII., 456; kinds of, 100; derivation of name, 107; Atmospheric, Chap. XIII., 217. Electrification, Chap. VI., 103, 116, 132, 134; and heat, 104; condensation of, Chap. X.; escape of, 155; free and bound, 162; induced, Chap. IX.; kinds of, 120; of earth, 222; source of in cells, 265; theories about, 145; two kinds of, 120, 211. Electrics and non-electrics, 134. Electrified bodies, 102, 107. Electrodes, 269. Electromagnetism, Chap. XXII., 383. Electromagnets, Chap. XXIII., 396; cores of, 397; horseshoe, 405. Electromotive force, 144, Chap. XVII., 296, 300, 303; measurement of, Exp. 140; of polarization, 373, 382; series, 301; unit of, 297. Electrophorus, 138; action of, 171, 172; our, 139. Electrolysis, 370. Electrolyte, 370. Electroplating, 376, 378. Electroscope, action of, 206, 208; carbon, 114; pith-ball, 200; our leaf, 201, 202. Electroscopes, Chap. XI. Electrotyping, 379. Equator of magnet, 13. Equipotential points, 326. External resistance, 307, 368. Extra current, 444; Exp. 199. Field, electric, 156; magnetic, Chap. IV., 62, 80; magnets, 476. Figures, magnetic, 64; permanent, 417. Force, 103; lines of magnetic, 64, 73, 80, 156; lines of electric, 156; lines of about a wire, 385. Franklin, Benjamin, 218. Free electrification, 162. Frictional electricity, Part II. Fulminating panes, 180. Galvanic cells, Chap. XV., 265; chemical action in, 270; various kinds of, 286 to 291. Galvanoscope, 240 to 249. Glass, as insulator, 136. Gold-leaf electroscope, 200, 209. Gravity cell, 291. Hardening steel, 8, 10. Heat, effect on resistance, 343; effect on magnet, 49. Horse-power, electric, 355. Horseshoe magnet, 11; advantages of, 82; electromagnets, 405. Hydrogen, 260, 262, 271, 278, 279, 373. Inclination of needle, 86. Induced currents, Chap. XXV.; and work, 429; and lines of force, 432, 435, 438; direction of, 439. Induced magnetism, Chap. III. Induction coils, 473; action of, 474; condensers of, 181; with telephone, 483. Induction, electromagnetic, 426; laws of, 440; static, theory of, 159; successive, 168. Inductive capacity, 169. Insulators, Chap. VII., 125. Internal resistance, 307, 314, 358, 362, 368. Iron and steel, Chap. I. Iron, hardening properties of, Exp. 4; impurities of, 1; kinds of, 2; soft, 10. Jar, Leyden, 179. Key, 233, 234. Lamp, arc, 485; incandescent, 486. Laws, of electrification, 121; of induction, 440; of magnetism, 29; of resistance, 349. Leclanché cell, 287. Leyden jar, 179. Lighting, 484, 485, 486. Lightning, 144, _a_; 218; rods, 220. Lines of force, about a wire, 385, 388; electric, 156; and induced currents, 432, 438; magnetic, 64, 73, 74, 80, 156; resistance to, 78, 397. Local action, 273. Local currents, 273. Lodestone, 93. Magnetic, bodies, 15; circuits, closed, 420; field, 62, 80; figures, permanent, 417; figures, 64, Exp. 161, 162, Exps. 168 to 171; force, lines of, 64, 80, 156; induction of the earth, 92; needle, 26; needles, balancing of, 88; needle, dip of, 86; problems, 33; saturation, 42; screens, 18; tick, Exp. 160; transparency, 18. Magnetism, Part I.; induced, Chap. III., 53; residual, 44, 53; temporary, 53; terrestrial, Chap. V.; theory of, 42; of earth, 83; laws of, 29. Magnets, bar, 21; compound, 73; effect of breaking, 51; equator of, 13, 51; experimental, 407; kinds of, 11; natural, 93; poles of, 13, 25; practical uses of, 16. Mercury, 274. Motion, production of, Chap. XXVI., 445, 452, 455. Motors, electric, 477. Mutual attractions, 111. Natural magnets, 93. Needle, astatic, 251, 253, 254; magnetic, 26, 32. Negative electrification, 120. Neutral bodies, 102. Non-conductors, 312. Non-electrics, 134. North-seeking poles, 25. Ohm, the, 308. Ohm's law, 356. One-fluid theory, 145. Open and closed circuits, 266; cells, 286. Oxygen, 372, 373, 382. Peltier effect, 424. Pith-ball electroscope, 200. Plates or elements, 267. Polarization of cells, 278; effects of, 279; electric, 159, 164; electromotive force of, 373; magnetic, 56; remedies for, 280. Poles, 13, 25, 64, 92; consequent, 39; of coils, 392; of electrodes, 269; reversal of, 35; rule for, 31. Pole pieces, 56. Positive electrification, 120. Potential, 133,144; energy, 103. Primary current, 441. Proof-plane, 209. Quantity, unit of, 354. Recorder, Exp. 197. Relay, telegraph, 462. Repulsion, laws of electrostatic, 121; laws of magnetic, 29. Residual, charge in condenser, 197; magnetism, 44; magnetism of core, Exp. 159. Resistance, coils, 309; effect of heat on, 343; electrical, Chap. XVIII., 305, 319, 321; external and internal, 307, 362, 368; internal, 314, 358; laws of, 349; to lines of force, 78; measurement of, Chap. XIX.; unit of, 308. Retentivity, 44, 46. Reverser, current, 235, 237. Rheostat, simple, 344. Saturation, magnetic, 42. Secondary cells, 382; current, 441. Self-induction, 444. Series arrangement of cells, 364. Shocks, 188. Short circuits, 295. Shunts, 293. Silk, as insulator, 136. Single-fluid cell, 275. Single needle telegraph, Exp. 194. Sounder, telegraph, 458. Spark, 144, _a_. Static electricity, Part II. Static electric machines, 216. Steel, Chap. I.; kinds of, 2; magnetism of, 42, 46, 49. St. Elmo's fire, 222. Storage cells, 382. Successive, induction, 168; condensation, 199. Sulphuric acid, 258, 262, 314. Tangent galvanometer, 352. Telegraph, line, 459, 460; relay, 462; single needle instrument, Exp. 194; sounder, 458; static, 130. Telephone, the, 479; Bell, 480; carbon transmitter, 482; with induction coils, 483; receiver, 481. Tempering steel, 8. Temporary magnetism, 53. Terrestrial magnetism, Chap. V. Thermoelectricity, Chap. XXIV., 423. Thermopile, 425; home-made, 421. Thunder, 219. Transformers, 475. Transmitters, 480, 482. Two-fluid cell, 280, 281; care of, 282; chemical action in, 285. Two-fluid theory of electrification, 146. Unit of, current strength, 351; E. M. F., 297; of power, 355; quantity, 354; resistance, 308. Variation, angle of, 84. Varieties of electricity, 100. Volt, the, 297. Voltameters, 297, 353, 380. Water, composition of, 372. Watt, the, 355. Wheatstone's bridge, 324 to 330. Wind, electric, 155. Wire tables, Chap. XXVIII. Yoke, use of, 406. Zero, potential, 144, _a_. Zinc, chemical action with, 271; with commercial, 273. Zinc plates, reasons for amalgamating, 274. Notes. Notes. ELECTRICAL BOOKS ELECTRICAL APPARATUS GAMES PUZZLES EDUCATIONAL AMUSEMENTS [Illustration] THOMAS M. ST. JOHN, Met. E. A Word to Parents About Games and Educational Amusements. Systematic play is as important as systematic work. The best games and home amusements are as valuable to a child as school-studies; in fact, they bring out and stimulate qualities in a child, which no school-study can. Fascinating home amusements are as necessary as school-books. Boys and girls like to be busy. Their amusements should be entered into as heartily, chosen as carefully, and purchased as willingly as school-books. =Games.=--JINGO and HUSTLE-BALL are good games. They are interesting and full of action. They arouse a child's common-sense. They cultivate an ability to think rapidly, judge correctly, and decide quickly. They educate the eye and hand at the same time. They are very simple, and may be played at once. =Educational Amusements.=--There is a peculiar fascination about Electricity and Magnetism, which makes these subjects appeal to every boy and girl. There is nothing better than science studies, to teach children to observe and to see what they look at; besides, it is _fun_ to experiment. "Fun With Electricity" and "Fun With Magnetism" are educational amusements. They contain fascinating experiments and are systematically arranged. Juvenile Work in Electricity. _From The Electrical Engineer, May 19, 1898._ The position that Young America is now taking in the electric and magnetic field is very clearly shown at the Electrical Show now being held at Madison Square Garden, by an exhibit of simple experimental apparatus made by young boys from the Browning School, of this city. The models shown cover every variety of apparatus that is dear to the heart of a boy, and yet, along the whole line from push-buttons to motors, one is struck by the extreme simplicity of design and the ingenious uses made of old tin tomato cans, cracker boxes, bolts, screws, wire, and the wood that a boy can get from a soap box. The apparatus in this exhibit was made by boys 13, 14 and 15 years of age, from designs made by Mr. Thomas M. St. John, of the Browning School. It clearly shows that good, practical apparatus can be made from cheap materials by an average boy. The whole exhibit is wired and in working order, and it attracts the attention of a large number of parents and boys who hover around to see, in operation, the telegraph instruments, buzzers, shocking coils, current detectors, motors, etc. Mr. St. John deserves the thanks of every boy who wants to build his own electrical apparatus for amusement or for experimental purposes, as he has made the designs extremely simple, and has kept constantly in mind the fact that the average boy has but a limited supply of pocket money, and an equally limited supply of tools. How Two Boys Made Their Own Electrical Apparatus. =CONTENTS:= _Chapter_ I. Cells and Batteries.--II. Battery Fluids and Solutions.--III. Miscellaneous Apparatus and Methods of Construction.--IV. Switches and Cut-Outs.--V. Binding-Posts and Connectors.--VI. Permanent Magnets.--VII. Magnetic Needles and Compasses.--VIII. Yokes and Armatures.--IX. Electro-Magnets.--X. Wire-Winding Apparatus.--XI. Induction Coils and Their Attachments.--XII. Contact Breakers and Current Interrupters.--XIII. Current Detectors and Galvanometers.--XIV. Telegraph Keys and Sounders.--XV. Electric Bells and Buzzers.--XVI. Commutators and Current Reversers.--XVII. Resistance Coils.--XVIII. Apparatus for Static Electricity.--XIX. Electric Motors.--XX. Odds and Ends.--XXI. Tools and Materials. "The author of this book is a teacher and writer of great ingenuity, and we imagine that the effect of such a book as this falling into Juvenile hands must be highly stimulating and beneficial. It is full of explicit details and instructions in regard to a great variety of apparatus, and the materials required are all within the compass of very modest pocket-money. Moreover, it is systematic and entirely without rhetorical frills, so that the student can go right along without being diverted from good helpful work that will lead him to build useful apparatus and make him understand what he is about. The drawings are plain and excellent. We heartily commend the book."--_Electrical Engineer._ "Those who visited the electrical exhibition last May cannot have failed to notice on the south gallery a very interesting exhibit, consisting, as it did, of electrical apparatus made by boys. The various devices there shown, comprising electro-magnets, telegraph keys and sounders, resistance coils, etc., were turned out by boys following the instructions given in the book with the above title, which is unquestionably one of the most practical little works yet written that treat of similar subjects, for with but a limited amount of mechanical knowledge, and by closely following the instructions given, almost any electrical device may be made at very small expense. That such a book fills a long-felt want may be inferred from the number of inquiries we are constantly receiving from persons desiring to make their own induction coils and other apparatus."--_Electricity._ "At the electrical show in New York last May one of the most interesting exhibits was that of simple electrical apparatus made by the boys in one of the private schools in the city. This apparatus, made by boys of thirteen to fifteen years of age, was from designs by the author of this clever little book, and it was remarkable to see what an ingenious use had been made of old tin tomato-cans, cracker-boxes, bolts, screws, wire, and wood. With these simple materials telegraph instruments, coils, buzzers, current detectors, motors, switches, armatures, and an almost endless variety of apparatus were made. In his book Mr. St. John has given directions in simple language for making and using these devices, and has illustrated these directions with admirable diagrams and cuts. The little volume is unique, and will prove exceedingly helpful to those of our young readers who are fortunate enough to possess themselves of a copy. For schools where a course of elementary science is taught, no better text-book in the first-steps in electricity is obtainable."--_The Great Round World._ Exhibit of Experimental Electrical Apparatus AT THE ELECTRICAL SHOW, MADISON SQUARE GARDEN, NEW YORK. While only 40 pieces of simple apparatus were shown in this exhibit, it gave visitors something of an idea of what young boys can do if given proper designs. [Illustration: "HOW TWO BOYS MADE THEIR OWN ELECTRICAL APPARATUS" Gives Proper Designs--Designs for over 150 Things.] JUST PUBLISHED. How Two Boys Made Their Own Electrical Apparatus. Containing complete directions for making all kinds of simple electrical apparatus for the study of elementary electricity. By PROFESSOR THOMAS M. ST. JOHN, New York City. The book measures 5 × 7-1/2 in., and is beautifully bound in cloth. It contains 141 pages and 125 illustrations. Complete directions are given for making 152 different pieces of Apparatus for the practical use of students, teachers, and others who wish to experiment. PRICE, POST-PAID, $1.00. The shocking coils, telegraph instruments, batteries, electromagnets, motors, etc., etc., are so simple in construction that any boy of average ability can make them; in fact, the illustrations have been made directly from apparatus constructed by young boys. The author has been working along this line for several years, and he has been able, _with the help of boys_, to devise a complete line of simple electrical apparatus. _THE APPARATUS IS SIMPLE because the designs and methods of construction have been worked out practically in the school-room, absolutely no machine-work being required._ _THE APPARATUS IS PRACTICAL because it has been designed for real use in the experimental study of elementary electricity._ _THE APPARATUS IS CHEAP because most of the parts can be made of old tin cans and cracker boxes, bolts, screws, wires and wood._ Address, THOMAS M. ST. JOHN, 407 West 51st Street, New York. Fun With Magnetism. BOOK AND COMPLETE OUTFIT FOR SIXTY-ONE EXPERIMENTS IN MAGNETISM.... [Illustration] Children like to do experiments; and in this way, better than in any other, _a practical knowledge of the elements of magnetism_ may be obtained. These experiments, although arranged to amuse boys and girls, have been found to be very _useful in the class-room_ to supplement the ordinary exercises given in text-books of science. To secure the best _possible quality of apparatus_, the horseshoe magnets were made at Sheffield, England, especially for these sets. They are new and strong. Other parts of the apparatus have also been selected and made with great care, to adapt them particularly to these experiments.--_From the author's preface._ =CONTENTS.=--Experiments With Horseshoe Magnet.--Experiments With Magnetized Needles.--Experiments With Needles, Corks, Wires, Nails, etc.--Experiments With Bar Magnets.--Experiments With Floating Magnets.--Miscellaneous Experiments.--Miscellaneous Illustrations showing what very small children can do with the Apparatus.--Diagrams showing how Magnetized Needles may be used by little children to make hundreds of pretty designs upon paper. =AMUSING EXPERIMENTS.=--Something for Nervous People to Try.--The Jersey Mosquito.--The Stampede.--The Runaway.--The Dog-fight.--The Whirligig.--The Naval Battle.--A String of Fish.--A Magnetic Gun.--A Top Upsidedown.--A Magnetic Windmill.--A Compass Upsidedown.--The Magnetic Acrobat.--The Busy Ant-hill.--The Magnetic Bridge.--The Merry-go-Round.--The Tight-rope Walker.--A Magnetic Motor Using Attractions and Repulsions. _The Book and Complete Outfit will be sent, Post-paid, upon receipt of 35 Cents, by_ THOMAS M. ST. JOHN, 407 W. 51st St., New York. A Few Off-Hand Statements that have been made about "Fun With Magnetism" and "Fun With Electricity" in letters of inquiry to the author. (These statements were absolutely unsolicited.) "My little boy has your 'Fun With Magnetism' and enjoys it so much that if the 'Fun With Electricity' is ready I would like to have it for him. Please let me know," etc. "I have had much fun with 'Fun With Magnetism.'" "My boy has 'Fun With Magnetism' and has enjoyed it very much and would like the other. Will you," etc. "Please let me know when 'Fun With Electricity' is upon the market, for if it is as good as this, I shall certainly want it." "I have just received 'Fun With Magnetism' and am delighted with it. Please send me 12 sets," etc. "I have 'Fun With Magnetism' and 'Fun With Electricity' and have enjoyed them very much. Please send," etc. "I am much pleased with 'Fun With Electricity' and would like to have," etc. "'Fun With Electricity' is fine and I have had lots of fun with it. Please send," etc. "Having experimented with both of your apparatus 'Fun With Magnetism' and 'Fun With Electricity,' and having found them both amusing and instructive, I wish to ask," etc. "I have purchased your outfits 'Fun With Electricity' and 'Fun With Magnetism,' and though they are designed for amusement, I find them a great help in my studies. Will you please," etc. "I have one of your outfits of 'Fun With Electricity,' and I enjoy it very much, some of the experiments being very astonishing. Will you please," etc. "I have enjoyed 'Fun With Magnetism' and 'Fun With Electricity' very much." "My little boy has your book 'Fun With Electricity,' which has given him much amusement. He would like to have," etc. "I am very much pleased with both outfits. I am very much in favor of such things for boys; it keeps them occupied with something that is both amusing and instructive. Send me," etc. Fun With Electricity. BOOK AND COMPLETE OUTFIT FOR SIXTY EXPERIMENTS IN ELECTRICITY.... [Illustration] Enough of the principles of electricity are brought out to make the book instructive as well as amusing. The experiments are systematically arranged, and make a fascinating science course. No chemicals, no danger. The book is conversational and not at all "schooly," Harry and Ned being two boys who perform the experiments and talk over the results as they go along. "The book reads like a story."--"An appropriate present for a boy or girl."--"Intelligent parents will appreciate 'Fun With Electricity.'"--"Very complete, because it contains both book and apparatus."--"There is no end to the fun which a boy or girl can have with this fascinating amusement." =THERE IS FUN IN THESE EXPERIMENTS.=--Chain Lightning.--An Electric Whirligig.--The Baby Thunderstorm.--A Race with Electricity.--An Electric Frog Pond.--An Electric Ding-Dong.--The Magic Finger.--Daddy Long-Legs.--Jumping Sally.--An Electric Kite.--Very Shocking.--Condensed Lightning.--An Electric Fly-Trap.--The Merry Pendulum.--An Electric Ferry-Boat.--A Funny Piece of Paper.--A Joke on the Family Cat.--Electricity Plays Leap-Frog.--Lightning Goes Over a Bridge.--Electricity Carries a Lantern.--And _=40 Others=_. The _=OUTFIT=_ contains 20 different articles. The _=BOOK OF INSTRUCTION=_ measures 5 × 7-1/2 inches, and has 38 illustrations, 55 pages, good paper and clear type. _The Book and Complete Outfit will be sent, by mail or express, Charges Prepaid, upon receipt of 65 Cents, by_ THOMAS M. ST. JOHN, 407 W. 51st St., New York. Fun With Puzzles. BOOK, KEY, AND COMPLETE OUTFIT FOR FOUR HUNDRED PUZZLES.... The BOOK measures 5 × 7-1/2 inches. It is well printed, nicely bound, and contains 15 chapters, 80 pages, and 128 illustrations. The KEY is illustrated. It is bound with the book, and contains the solution of every puzzle. The COMPLETE OUTFIT is placed in a neat box with the book. It consists of numbers, counters, figures, pictures, etc., for doing the puzzles. =CONTENTS=: _Chapter_ (1) Secret Writing. (2) Magic Triangles, Squares, Rectangles, Hexagons, Crosses, Circles, etc. (3) Dropped Letter and Dropped Word Puzzles. (4) Mixed Proverbs, Prose and Rhyme. (5) Word Diamonds, Squares, Triangles, and Rhomboids. (6) Numerical Enigmas. (7) Jumbled Writing and Magic Proverbs. (8) Dissected Puzzles. (9) Hidden and Concealed Words. (10) Divided Cakes, Pies, Gardens, Farms, etc. (11) Bicycle and Boat Puzzles. (12) Various Word and Letter Puzzles. (13) Puzzles with Counters. (14) Combination Puzzles. (15) Mazes and Labyrinths. "Fun With Puzzles" is a book that every boy and girl should have. It is amusing, instructive,--educational. It is just the thing to wake up boys and girls and make them think. They like it, because it is real fun. This sort of educational play should be given in every school-room and in every home. "Fun With Puzzles" will puzzle your friends, as well as yourself; it contains some real brain-splitters. Over 300 new and original puzzles are given, besides many that are hundreds of years old. =Secret Writing.= Among the many things that "F. W. P." contains, is the key to _secret writing_. It shows you a very simple way to write letters to your friends, and it is simply impossible for others to read what you have written, unless they know the secret. This, alone is a valuable thing for any boy or girl who wants to have some fun. _The Book, Key, and Complete Outfit will be sent, postpaid, upon receipt of 35 cents, by_ THOMAS M. ST. JOHN, 407 West 51st St., New York City. Fun With Soap-Bubbles. BOOK AND COMPLETE OUTFIT FOR FANCY BUBBLES AND FILMS.... [Illustration] =THE OUTFIT= contains everything necessary for thousands of beautiful bubbles and films. All highly colored articles have been carefully avoided, as cheap paints and dyes are positively dangerous in children's mouths. The outfit contains the following articles: One Book of Instructions, called "Fun With Soap-Bubbles," 1 Metal Base for Bubble Stand, 1 Wooden Rod for Bubble Stand, 8 Large Wire Rings for Bubble Stand, 1 Small Wire Ring, 3 Straws, 1 Package of Prepared Soap, 1 Bubble Pipe, 1 Water-proof Bubble Horn. The complete outfit is placed in a neat box with the book. (Extra Horns, Soap, etc., furnished at slight cost.) =CONTENTS OF BOOK.=--Twenty-one Illustrations.--Introduction.--The Colors of Soap-bubbles.--The Outfit.--Soap Mixture.--Useful Hints.--Bubbles Blown With Pipes.--Bubbles Blown With Straws.--Bubbles Blown With the Horn.--Floating Bubbles.--Baby Bubbles.--Smoke Bubbles.--Bombshell Bubbles.--Dancing Bubbles.--Bubble Games.--Supported Bubbles.--Bubble Cluster.--Suspended Bubbles.--Bubble Lamp Chimney.--Bubble Lenses.--Bubble Basket.--Bubble Bellows.--To Draw a Bubble Through a Ring.--Bubble Acorn.--Bubble Bottle.--A Bubble Within a Bubble.--Another Way.--Bubble Shade.--Bubble Hammock.--Wrestling Bubbles.--A Smoking Bubble.--Soap Films.--The Tennis Racket Film.--Fish-net Film.--Pan-shaped Film.--Bow and Arrow Film.--Bubble Dome.--Double Bubble Dome.--Pyramid Bubbles.--Turtle-back Bubbles.--Soap-bubbles and Frictional Electricity. "There is nothing more beautiful than the airy-fairy soap-bubble with its everchanging colors." _=THE BEST POSSIBLE AMUSEMENT FOR OLD AND YOUNG.=_ _The Book and Complete Outfit will be sent, POST-PAID, upon receipt of 35 cents, by_ THOMAS M. ST. JOHN, 407 West 51st St., New York City. Things A Boy Should Know About Electricity. (In Preparation.) This book explains, in simple, straightforward language, many things about electricity; things in which the American boy is intensely interested; things he wants to know; things he should know. It is free from technical language and rhetorical frills, but it tells how things work, and why they work. It is brimful of illustrations--the best that can be had--illustrations that are taken directly from apparatus and machinery, and that show what they are intended to show. This book does not contain experiments, or tell how to make apparatus; our other books do that. After explaining the simple principles of electricity, it shows how these principles are used and combined to make electricity do every-day work. The following are _Some of the Things Electricity Can Do:_ It signals without wires. It drills rock, coal, and teeth. It cures diseases and kills criminals. It protects, heats, and ventilates houses. It photographs the bones of the human body. It rings church bells and plays church organs. It lights streets, cars, boats, mines, houses, etc. It pumps water, cooks food, and fans you while eating. It runs all sorts of machinery, elevators, cars, boats, and wagons. It sends messages with the telegraph, telephone, telautograph, and search-light. It cuts cloth, irons clothes, washes dishes, blackens boots, welds metals, prints books, etc., etc. _Everyone Should Know About Electricity._ =Things A Boy Should Know About Electricity= will interest _you_. We shall be glad to send you complete information as soon as it is ready. Send us your address now. Dewey Flag Poles =ARE LITTLE MODELS OF REAL FLAG POLES....= [Illustration] They are appropriate for any occasion, and suitable for any kind of decoration. They should stand on tables, mantels, pianos, etc.; in fact, there is no better ornament for general use. "They should be in every home and in every school-room in the United States." "No toy fort complete without a Dewey Flag Pole." "The children can fasten them on the windowsill and watch them flutter by the hour." "They hoist like big flags, at half-mast, etc." "Invaluable for store-window decoration." [Illustration] PRICES SMALL SIZE: height 18 inches, fitted with United States or Cuban Silk Flag (4×6 in.) post-paid, 30c. LARGE SIZE: height 24 inches, fitted with United States Silk Flag (7 × 10 in.), post-paid, 40c. LARGE SIZE: fitted with Cuban or British Silk Flag (8×12 in.), post-paid, 50c. _DEWEY FLAG POLES are beautifully made of hard wood, and fitted with best Silk Flags_. GAMES. Hustle=Ball. A quick, sharp, decisive game that is thoroughly American. Played by means of Magic Wands, and Polished Balls of Steel. _=Needed:= "A quick eye and a nimble hand."_--_Shakespeare_. _The Rule: Just keep cool--and hustle._ Four Games with One Outfit: "Hustle Ball," "Leap-Frog," "Cross-Country Race," "Magnetic Potato-Race." The game-board is new and original, as well as the methods of playing. The game is put up in a strong box having a beautifully lithographed cover, and measures 8 × 15-1/2 inches. With the game-board are furnished, magic wands, polished steel balls, an "extra strength" horseshoe magnet, and a complete set of illustrated rules and directions for playing. "Unlike all other games." "Any one can play Hustle-Ball." "Just the thing for progressive parties." "Hustle-Ball games are intensely exciting." "No waiting for some one to play." "You win or lose a point in a few seconds." "By handicapping the best players, all games are made equally interesting and exciting." "A game for Grandparents, as well as for Grandchildren." A Brand-New Idea in Games. [Illustration] [Illustration] '_A HUSTLE FROM THE WORD GO._' _=This Exciting Game=_ will be sent, _=Charges Prepaid=_, by mail or express, upon receipt of 65 Cents. Address THOMAS M. ST. JOHN, 407 West 51st Street, New York City. JINGO THE GREAT WAR GAME Social Exciting Interesting Simple. A Thorough War Game:--Infantry Against Infantry, Cavalry Against Cavalry, Etc. Jingo is really a great war contest between England and America. Upon the game-board are 14 beautiful war scenes, each lithographed in 8 colors. American and English flags, coats of arms, cannon, torpedoes, etc., aid in making this game artistic, handsome and attractive. The following companies, ships, etc., are shown:--_American_, 12th U. S. Infantry,--6th U. S. Cavalry,--2d U. S. Light Artillery,--U. S. Mortar Battery,--U. S. Monitor "Miantonomoh,"--U. S. Ram "Katahdin,"--U. S. Battleship "Indiana,"--U. S. Torpedo Boat "Cushing,"--U. S Dynamite Cruiser "Vesuvius." _English_, 30th East Lancashire,--1st Royal Dragoons,--Royal Horse Artillery,--Royal Artillery,--H. M. S. "Thunderer,"--H. M. S. "Seagull,"--H. M. S. "Nile,"--H. M. S. "Australia,"--H. M. S. "Dart." The game board is over 16 inches square when opened. Jingo is made and finished in a manner which makes it the most beautiful, artistic, and practical game ever published. "Just what every boy likes." "A good idea well carried out." "The Game-board is a work of art." "Any child can play Jingo at once." "It is the handsomest game on the market." JINGO JUNIOR is the Greatest Game ever Invented for Little Folks. It is played upon the Jingo board with the extra ammunition furnished. These Two Great Games make a most complete and beautiful outfit for home amusement. JINGO AND JINGO JUNIOR. Two Fascinating and Entirely Different Games, Played with One Outfit, and Complete in One Box. [Illustration] _THIS HANDSOME OUTFIT_ for playing the _TWO GREAT WAR GAMES_ will be sent _CHARGES PREPAID_ upon receipt of _=$1.00=_. Address THOMAS M. ST. JOHN, 407 West 51st Street, New York City. Transcriber's Notes In the text version, Italic text is denoted by _underscores_ and bold text by =equal signs=. Obvious punctuation errors have been repaired. The book contains some inconsistent hyphenation which has been left as printed. p. xi. (TOC) "constructiou" changed to "construction" p. xiv. (TOC) "The Prodution of Motion" changed to "The Production of Motion" p. 27. para. 73. "thick permament magnets" changed to "thick permanent magnets" p. 99. para 253. "wabble" may be a typo for wobble but has been left on the off chance that this could be what was intended. p. 118. Fig 91. The final column has been scored through but appears to read "CU to ZN" p. 131. para. 324, 325. German-silver Wire, G-s W used here but previously G S W used. p. 164. para 395. "circuit in closed" changed to "circuit is closed" p. 166. para 398. "core inside of the c l" changed to "core inside of the coil" after checking original scans. p. 169-170. It appears that a word has been omitted across the page break. "The copper washer, C W, be used." has been changed to "The copper washer, C W, should be used.". (Alternative words are possible!) p. 211. No. 35. 5-16 in. changed to 5/16 in. p. 213. No. 92, 93. 5-16 in. changed to 5/16 in. p. 214. No. 96. and No. 97. 5-16 in. changed to 5/16 in. p. 216. Entry for Coulomb moved from end of "C" to above Current. 
59535	----	Project Hi-Psi BY FRANK RILEY _The aliens were conducting an experiment under laboratory conditions. So, how could they guess that their guinea pigs held the ultimate weapon?_ [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, August 1956. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] Dr. Lucifer Brill stepped briskly down the corridor of the Federal Building. The taps on his leather heels clicked a precise rhythm on the marble floor. He ignored the door that offered "Information", passed up office after office until he came to the glass paneled door which informed him that behind it functioned the Director of FBI operations in the Los Angeles area. The door was locked. Lucifer Brill rubbed the knuckles of his left hand over the bristles of his sand-colored, neatly trimmed bit of mustache. It was a gesture known to all graduate students, Department of Parapsychology, Western University, as an indication of annoyance. The possibility of this office being closed had definitely not been part of Lucifer Brill's prospectus. A movement behind the opaque glass panel caught his attention. He rattled the knob. When this produced no results, he tapped with his immaculate fingernails on the glass. A shadow moved inside the office. The lock clicked. The door opened. An overweight young woman, obviously interrupted in the act of painting a lush mouth over thin lips, glared at him through a veneer of politeness. "Yes?" "I have an appointment with the Director." Lucifer Brill's voice still carried the twang of boyhood in Chelmsford, Mass. The young woman's plucked eyebrows arched. "This office is closed. If there is an emergency, you may...." Lucifer handed her his card. The eyebrows arched still higher. "Dr. Brill! Your appointment was for 3:45!" "I am aware of that," he told her, severely, "but the other drivers were not, and there were an incredible number of them on the road. Now, if you please...." "Would you care to make another appointment for tomorrow?" "I would not. You may inform the Director that I have arrived, that I regret my tardiness and that the purpose of my visit involves a matter of extreme urgency." Lucifer hadn't raised the level of his voice, but behind the rimless spectacles, his mild blue eyes became very cold and direct. The secretary unpursed her lips and flounced toward the inner office. She was back in a moment, and said with disapproval, "This way, please--Sir." The Director greeted Lucifer Brill with a courtesy that was somewhat strained. His briefcase was on his desk. So was his hat. Lucifer went peremptorily to the point. "I must report a most serious case." From long training, the Director ignored the tone and inquired with careful politeness. "What sort of a case, Dr. Brill?" "I believe you would call it a case of kidnapping--multiple kidnapping." "Kid--kidnapping!" The Director's large hands hit the desk top with a cracking sound. His knee touched a button to flip on the tape recorder. "When?--Where?--Who?" Lucifer considered the questions, methodically organized his answers. "As to when, I would say over the last eight years." "What?" "As to where, I would say all over the United States." "Now, one moment ... please!" "As to who.... Well, that would require a rather lengthy answer." The Director's voice shook with an effort to keep calm. "Dr. Brill, I would appreciate an answer to my question." "Very well." Lucifer took a small, brown leather notebook from the inside pocket of his beautifully pressed gabardine. "It will take a little time. You see, I believe that over 3,000 persons have been kidnapped." The Director's thick neck turned prime-rib red, and swelled over the collar of his shirt. Lucifer began to read: "Anthell, Ruth ... Atwater, Horace ... Borsook, George...." "That's enough, Dr. Brill!" "Thank you. Time really is of the essence, you know. I learned this morning that two of the missing persons disappeared as recently as four days ago." The Director breathed heavily. "Just who are these people, Dr. Brill?" "They are all positives. Some of them are positive positives." The Director made a small, strangling sound. "If you don't mind, Dr. Brill--just what in the hell are positive positives?" "Oh, I'm sorry. I had presumed you were familiar with my work." "I'm a little vague about it." "I see." Lucifer's expression showed intolerance for this cultural lag, but he condescended to explain. "For several years I have been re-evaluating psi card tests at Western University, with the project goal of answering criticism that Rhine and other researchers ended scoring runs at so-called convenient points. While one cannot approach the statistical ideal of infinity in any series, it is nevertheless mathematically possible, through multitudinous repetitions...." There was an expression on the Director's face of a man trying to plod doggedly against a strong gale. "Positives ..." he reminded, a little desperately. "... to amass statistics that are conclusively beyond the bounds of chance. In this rechecking, I have received excellent cooperation from researchers at other universities, and consequently have compiled what may well be the largest list of psi cases on record, whereby...." "Positives," grated the Director. "Kidnapping ... remember, Dr. Brill...?" "... I have been able to establish categories--in my own terminology--of non-positives, positives and positive-positives. Do you follow me, Sir?" "Absolutely." The FBI Director removed sweat from his forehead with the back of his hand. "Now, shall we get on with this kidnapping...." "I am convinced that my positives and positive positives are either being kidnapped, or otherwise caused to disappear involuntarily." "3,000 of them?" "3,116." The Director, in this crisis, took refuge in routine. He picked up Lucifer's card. "Do you have any other identification with you, Dr. Brill." The routine was a mistake. Lucifer produced an expired driver's license, an unpaid gas bill, a membership card in the American Society for Psychic Research, a faculty football ticket, a credit slip from the May Company, six traffic citations.... The Director held up his hand in weary surrender. "O.K.," he said. "Tell me all about it." Lucifer told his story with an admirable lack of detail, and a certain intensity that compelled attention. At a certain phase of his project, it was necessary to start re-evaluating cases he had previously re-evaluated. That phase had been reached two months ago. He had selected five hundred names from his card file, and had sent them form letters preparatory to arranging for tests. When 480 came back marked "Address Unknown", or "No Forwarding Address", he was disturbed, but not unduly so. In an era of great population shifts, people could be lost and forgotten. He mailed out another 500 forms. Four hundred and sixty-three came back unopened. A third mailing brought similar results. Subsequent mailings added up to the startling statistic that some 3,000 people apparently had vanished. Lucifer personally checked a score of names in the greater Los Angeles area. Five could not be located; seven seemed to have moved without leaving a forwarding address; one was reported drowned in the surf off Point Fermin; six were listed with the Missing Persons Bureau. Of the latter, two had briefly made headlines. They had kissed their wives goodby, driven off to work and had never been seen again. Against his will, the FBI Director was impressed by Lucifer Brill's calm recital of these facts. "But 3,000 people," he demurred. "Isn't it simply incredible that 3,000 people could disappear without causing a commotion?" "Do you know the number of missing persons listed annually by the Los Angeles Police Department?" The Director admitted he did not. "Nearly 4,000 juveniles and adults. The number in other cities is roughly proportionate to the population ... New York, for example, had about eight...." The FBI Director made his decision. "Dr. Brill," he said, "Give me that list of names and addresses." * * * * * Within twenty-four hours, teletypes began pouring in from the District Offices of the Federal Bureau of Investigation. Individually, the reports meant nothing. Obscure people who simply were missing. Many of them were not even missed enough to be listed as missing persons. The final tabulation showed that 3,223 men and women were missing out of 4,775 people who had registered significantly above-chance in the psi re-evaluation tests conducted by Western University. Lucifer Brill pointed out something else. "The missing positives were my stronger positives. Most of those who have not disappeared were closer to borderline cases." At this point, to the infinite relief of the Los Angeles office, prime responsibility for the case shifted to Washington, D.C. A tight lid of security was clamped over the whole affair. FBI analysts went to work on the facts and figures. Mathematically, they proved that the percentage of missing psi test cases was fantastically above the probability of coincidence. One by one, the people had dropped from sight, lost in the swirling undercurrents of a vast, shifting population. A school teacher in Little Rock, a side-show freak in Chattanooga, a TV salesman in Milwaukee, an artist in Philadelphia--all had disappeared, obscurely but definitely. And the disappearances were continuing. Only two days before an inquiring FBI agent called on a pharmacist in Dubuque, the man had closed up the drugstore, started for home and had never been seen again. He was listed as an amnesia victim at the local police department. In his psi test, four years earlier, he had consistently averaged seventeen out of twenty-five calls. Remorselessly, the accrual of new facts added to the Bureau's bewilderment. One of the FBI statisticians pointed out that almost an identical number of men and women were missing: 1,596 men; 1,627 women. Another perceptive young researcher ran cards on the missing positives through an IBM machine, and came up with this statistic: The women were between the ages of 17 and 35; the men between 19 and 45. Eighty percent of both sexes were in their late twenties. When all possible data had been assembled, the FBI gingerly submitted its report to a super-secret meeting of the Central Intelligence Agency. The reaction was not flattering. Navy's slightly profane comment was that someone in the Bureau had flipped his wig. Army looked disgusted. State Department was pained. White House was silent. The Chairman smiled, and waited for someone else to laugh. No one laughed. Red-faced but unyielding, FBI insisted that its report merited serious consideration. "We've kept this thing quiet," FBI said, "but you know what the reporters could do with it." State looked less pained. Even Army and Navy gave reluctant attention. White House asked tentatively, "What about the Russian angle? If even a fraction of this nonsense we hear about psi is true, these people might serve an espionage purpose. Could Soviet agents have smuggled them out of the country?" "A few, maybe," admitted FBI. "But not 3,223. Not by any known method of transportation." "Any subversives among them?" asked Army. "One hard-shelled Commie, a few fuzzy-minded joiners ... about par for the course." "Then why in the hell is this important, anyway?" demanded Navy. A large hassle ensued, but all eventually agreed that if more than 3,000 people actually had been caused to vanish, it was at least potentially a cause for security concern. Army pointed out: "Next time, they might not waste the effort on these crackpots. They might bag some important people." White House asked: "What are we going to do about it?" There was an outburst of silence. Finally, State spoke up: "By all means, keep the matter quiet. It could be deucedly embarrassing." But something, of course, had to be done. And while something was being debated, at top level, in top secrecy, in eyes-only, Q-clearance sanctums, Lucifer Brill took matters into his own hands. He felt a compelling personal responsibility to the missing people. Their names had been compiled together in his files; he had made no effort to protect the lists. Anyone who wanted to make the attempt could have found a way to copy the cards. Lucifer also felt a sense of responsibility to science. And by science, he meant his own branch of parapsychology. All other science existed for him in a vague limbo into which no serious psychological student would venture. "Nuts and bolts," was the way Lucifer customarily dismissed the shadow-world of science outside his own laboratory. But what use was it to go on confirming and re-confirming the existence of positives and positive positives if they just up and disappeared? The answer was discouraging. So Lucifer Brill took stock of himself. He was forty-four years old. He had no dependents, and was dependent on no one. Except for chronic nearsightedness, and hay fever in the months of July and August, he was sound of limb and body. Lucifer withdrew from the bank the balance of his inheritance and life savings. He placed the money in a trust fund to be given to Western University for continuance of psi research, five years after his death or disappearance. He drew up a holographic will bequeathing and bequesting his library and papers to the University. He prepared a sealed envelope containing three hundred dollars in cash and instructions for the care of his two parrots for the balance of their natural lives. And then Lucifer Brill released to the profession the news that after testing thousands of people for the psi talent, he had finally tested himself--and had scored an average of 19 out of 25 in 4,000 PT tests, all conducted under strict laboratory conditions. Parapsychological circles reacted with an affectionate blend of awe and amusement. Fellow professors wrote him congratulatory notes, some with postscripts that jibed at him goodnaturedly. The editors of two psychic journals called to ask for articles. One Eastern university wanted to test him for PC and PK, but Lucifer stalled for time, waiting for something or someone to cause him to vanish from the face of the earth. On the evening of August 23, about eight-thirty, there was a knock on the screen door of his bachelor apartment. Lucifer called, "Come in, please," but he continued to work at a statistical tabulation. The door opened; footsteps approached his desk. "Sit down," said Lucifer. He had been expecting a summer school graduate student to come by for a book. "I'll be through with this column in just a moment." "There is no hurry, Dr. Brill." The voice was strange. It had almost a metallic ring. Lucifer's fingers turned white where they gripped the pencil. But he carefully totalled up the column and rechecked the answer, ferreting out an error in the addition of 29 plus 8. Only then did he swivel around to face the tall, thin, dark-faced stranger. Lucifer said quietly, "Good evening. I am sorry to have kept you waiting." The stranger nodded, and took a small blue phial from his pocket. Long, lean-muscled fingers squeezed the phial. Lucifer's apartment faded gently away in the sweet, cloying odor of hyacinth. * * * * * When Lucifer Brill opened his eyes, his face was half buried in a white pillow. A damp breeze blew across the back of his neck. The breeze was heavy with tropical odors. Yet there was something curious about them. Lucifer sniffed, and sniffed again. He discovered that his hay fever wasn't bothering him. Through one probing eye, Lucifer could see his glasses on a nightstand. Beyond them was a window down which drops of rain were beginning to streak. Memories of the blue phial and the strange visitor flooded back. His right arm was numb, but he decided he had been sleeping on it. He experimented with his toes and legs. They moved. His right knee bumped against an object on the other side of the bed. The object felt alien to anything in Lucifer Brill's previous experience. He pushed firmly with his knee, and felt something that was both firm and soft, yielding and unyielding, warm and slightly cold. There was a sleepy murmur of protest, and the alien object moved away. Lucifer Brill obeyed habit. He reached for his glasses. Then he raised himself on his tingling right elbow and peered cautiously toward the other side of the bed. By many standards, Lucifer could have been adjudged a brave man. But what he saw had a curiously frightening effect on him. He saw the back of a woman's head, and a tangle of dark hair, a bare, sun-brown arm, a bare shoulder. Lucifer took off his glasses, breathed upon them, polished them thoughtfully on a corner of the sheet, and looked again. The apparition was still there. Only now the head was turned. The eyes that were watching him were wide and startled. The lips moved in sort of a gasping sound. They framed the words: "Get out of my bed!" In spite of a certain paralysis, Lucifer bridled at the words. He was a rational man, and believed that words should originate in a context of rationality. "I can assure you," he stated, "that I am not voluntarily in your bed, and that I have no intention of remaining here." There was another gasping sound. The eyes widened still more. The lips exclaimed. "Dr. Brill! Dr. Lucifer Brill!" Lucifer made a sound that was as close to a gurgle as he had come since infancy. When he had collated his emotions, he asked in his customary tone, "Have we met?" The lips smiled wryly. "It looks that way." "Ah ... Yes, of course. But, I mean ... under social or professional circumstances?" "You're the odd little man who gave me those card tests in San Diego last winter." Lucifer Brill digested this information in dignified silence. He considered the woman gravely, then took the white sheet and covered her up to her chin. She gasped again. "There are certain proprieties," he reminded her severely. He considered her again, trying to place her face and its personality among the thousands of people he had psi-tested. It was what he would term a Type III face, although he had never been able to establish any defineable connection between bone structure and psi positive characteristics. This was a strong face on the pillow beside him. Strong and at the same time possessed of certain female qualities, principally in the fullness of the rather large lips and in the throat lines. The cheek bones were fairly high. The skin texture indicated a chronological age of about thirty. Having thus appraised and catalogued the woman, Lucifer asked, "May I have the privilege of making your acquaintance?" "Wh ... what?" "Your name," he said impatiently. "Do you mind telling me your name?" "Nina ... Nina Poteil. They call me Nina ... professionally." "Professionally ...." Lucifer rolled the word on his tongue as though he relished its flavor. "May I inquire as to the nature of your profession?" "You don't remember? Oh, well, I guess you'd call me a psychologist." "A psychologist!" Lucifer's eyes glowed with relief and approval. If he had to awake to find himself in these distressing circumstances, it was good to know that he was with a confrere. "Really!" he said. "I had no idea! It astonishes me that I do not remember you. What is your specialization?" "I'm called an entertainment psychologist." "How extraordinary! Where do you practice?" "At the Blue Grotto on Fifth Street. I'm billed for character readings. Cards are my medium, but I don't need them, of course." "Oh." Lucifer adjusted his glasses. He said, "Now, if you will kindly face toward the opposite wall, I will get out of this bed." As Lucifer climbed out of bed, he was painfully conscious of a short kimono that scarcely reached to his white, bony knees. Panic-stricken, he looked around for something else to wear, and found some neatly folded garments on a chair behind his side of the bed. With a shock, he realized this was exactly the way he had always left his own clothes overnight. Only these were not his own clothes. They appeared to be made of a light, semi-transparent plastic material. There was a pair of trousers that fit rather like jodhpurs, a loose, practical tunic, and boots of the same thin material. When he had dressed, he still felt like a man in a goldfish bowl. Looking out the window, he saw that they were near the center of a very large compound, comprising hundreds of small dwellings, all constructed of a slate-like grey metal. Each dwelling was surrounded with a neat area of what appeared at first glance to be a lawn. On closer observation, it was a lush, mossy growth, deep green in color. At one end of the compound was a much larger building, sprawling into many wings and substructures. Behind it rose a tremendous, yet somehow slender and graceful, silhouette of a shining projectile, aimed toward the clouds. Around the compound, at intervals of about two hundred yards, were tall guard towers. The compound itself seemed to be located in a vast, towering forest that rolled away in all directions until it disappeared in the low-hanging mists. Through a break in the clouds, Lucifer saw a giant, orange wheel, many times the size of the sun he had known all his life. "Amazing," Lucifer murmured. Averting his eyes from the bed, he walked across the room and opened a door. It led to a large, bright room, artificially lighted from a source he could not determine. At the far end of the room were a door and glass casement windows that opened on a small, mossy clearing. The forest curved in behind the clearing, and walled it off. In the room itself, a large screen occupied most of one wall. The furniture was extremely functional. Everything, even the cushions on a low couch, appeared to be made of a tinted metal. But when Lucifer touched one of the cushions, it yielded resiliently. "Amazing," he repeated. In his astonishment, Lucifer forgot himself and looked toward the bed. "Miss Poteil, have you any idea where we are?" "I woke up after you did," she reminded him. "I see." He regarded her sternly. "What is your last recollection prior to awakening?" "I don't know.... Yes, I do!" She sat up, then sank back and covered herself again as he glared disapproval. "I was in the Blue Grotto--It was getting late, and I had just left my card--like I always do--at a table where two men were drinking. One of them said, 'Sure, we want a reading.' Then I sat down, and that's all I remember." "All?" he insisted, as if questioning a reluctant student. "There was kind of a strange odor...." "I know." "You do!" She bolted upright, forgetting the sheet. She looked accusingly at him. "Naturally, I recall the same odor. How else do you suppose I happened to wake up in this bed?" "I wondered." Lucifer turned back to the window in time to see two men, in the same plastic tunic and leggings he was wearing, approaching the front of their bungalow. "We have visitors," he said. "Perhaps we shall also have some answers. While I greet them, I suggest that you make an effort to acquire some kind of apparel." * * * * * One of the visitors was a gaunt, heavy-boned man, exceedingly tall. Lucifer guessed his height at close to seven feet. The bone structure of his face was harsh and massive. His head was shaved; the flesh deeply bronzed. The second visitor was nearly as tall, but he was older, and his shoulders sagged. Bronze skin hung loosely over the bones of his face. After a cautious glance over his shoulder indicated that Nina had stepped into the semi-transparent leggings and tunic that appeared to be standard garb, Lucifer opened the door and faced the men coming up the path. The younger of the two nodded. "Good morning, Dr. Brill." His voice had the same metallic timbre that Lucifer had first heard from the tall visitor in his own study. The older man stepped close to Lucifer and gazed intently into his eyes. "He has emerged," he said. "Good. In that case, we must introduce ourselves all over again." The large man bowed slightly, then drew himself stiffly erect. "Dr. Brill, in your language, my name would approximate the phonetic sounds: Huth Glaspac. You may call me Huth. I am the Administrative Director of this project." He indicated his older companion. "This is our medical director. For simplicity, you may call him Dr. Thame." Lucifer studied them gravely. "Come in, Gentlemen," he said. Awkwardly, he went through the motions of introducing them to Nina. Dr. Thame examined Nina's eyes, and nodded. "Our laboratory calculations were correct," he pronounced in a brittle voice that reflected satisfaction. To Nina and Lucifer he explained. "Due to the differing metabolisms of your bodies, it required a rather delicate calculation to bring you both out of the drug at the same time. It was estimated to occur about four cintros ... that is, hours ... ago, during your sleep...." "Gentlemen," Lucifer interrupted impatiently, "do you mind telling us where we are and what this is all about?" Huth's massive bronze features lightened with the shadow of a smile. "It is doubtful that the answer to either question will be helpful at this time. However, in response to the first, may I inquire: Have you studied astronomy?" Lucifer drew himself up with dignity. "I am a Parapsychologist." Again there was the shadow of a smile on Huth's bronze features. "The extreme specialization of your science will never cease to amaze me. At any rate, you are on the planet Melus, one of the outer planets of the star which your Earth astronomers call Capella, and which they place in the constellation of Auriga." Lucifer blinked rapidly and rubbed the bristles of his mustache with more than ordinary vigor. Some of his colleagues at Western University had worked on rocket projects. He had always suspected they were fools; now he was sure of it. Why else would they be wasting their time with rockets, while another race was running around the universe, kidnapping positives? It was Nina who spoke up first, her dark, deep-set eyes burning with excitement. "Capella ... I know!" she exclaimed. "Sometimes I work with the medium of astrology. It doesn't mean anything, really, no more than the cards. I could do just as well without either. But the customers.... Say, unless you're not telling the truth, Mr. Huth, we're quite a ways from San Diego!" "The distance is not important," said Huth. "Melus is now your home, and will be for the rest of your lives." As the import of his words reached them, Lucifer blinked again. Nina sat down on the edge of the steel-grey couch. "For the rest of our lives," she repeated wonderingly. "That's a long time." "It is to be hoped," said Dr. Thame. Lucifer had to speak with more than usual severity in order to keep the tremor out of his voice. "I asked two questions," he reminded Huth. Huth nodded. "Your second question will be answered during your orientation period." "And how long does that last?" "It varies. For you, Dr. Brill, it could be much longer than for your wife." "My--" This time, Lucifer's dry New England twang definitely broke. "Oh, yes. We learned that by observing the rituals of your culture we can minimize emotional trauma and thereby hasten orientation." He turned to Nina. "I can assure you that the proper Earth rituals were performed in the prescribed manner. Since neither of you were married, we could dispense with the Earth divorce ritual and perform only the marriage ritual. Does that ease your mind?" She stared at him without answering. Lucifer's temper bristled. "I refuse to recognize such mockery. It is immoral, illegal and definitely unethical." Huth dismissed the matter with a slight shake of his massive head, and proceeded to explain some of the objective facts of their situation. During orientation period, they would be required to remain on their own premises, except for their educational sessions at Center. They would be taken to Center once or twice each day, depending on their progress. Food preparation was handled at the Project commissary. Huth opened a small pantry. Meals, cooked by molecular agitation in the commissary, would be delivered to the pantry via the commissary tubicular. He showed them how to turn on the visagraph screen. "This is used for communication, education and also entertainment. You will find it very pleasant to read micro-filmed books off the screen. We also have a rather complete repertory of Earth music. After orientation, you will be assigned duties, and, of course, can become acquainted with fellow members of this project." Dr. Thame added briefly that Melus had been chosen for the project because it was a hydrogen-oxygen planet similar to Earth, although almost uniformly tropical. The inner planets of the system were not inhabitable, since Capella, with three times the mass of Sol, produced one hundred times more heat. "You'll discover that members of your Project have given this planet another name," he concluded. "But don't let it disturb you." Nina spoke up suddenly. "The name is--It's Mendel's Planet!" A muscle twitched in Huth's bronze cheek. "How did you know that?" She shook her head. "I never know how. Things just come to me. Sometimes I say--said things to my customers at the Blue Grotto, and they would ask me the same thing. How do I know?" She shrugged her strong shoulders. "How does anyone know they know anything?" Huth and Dr. Thame exchanged quick glances. "Very interesting," said Huth. He moved toward the door. "We will send for you in two hours for your basic family record test." "Basic fam--." Lucifer choked on the word. He asked bleakly. "What might that be?" "It will be elementary to you, Dr. Brill. Just a basic psi-card test. We have your record, of course, but for purposes of standardization, we always start a new family's record in this manner. You undoubtedly will score rather close to your high test score on Earth." Lucifer hoped his apprehension did not show. He had not expected having to meet this challenge so soon. Nina had been pursing her lips, frowning and thoughtful. Now she asked. "Mr. Huth, how long have we, Dr. Brill and I, been here on Melus?" A hint of humor flickered in Huth's somber eyes. "Two Earth months." * * * * * For several moments after their departure, Lucifer stalked silently around the room. Nina remained on the couch. Her eyes were closed; her hands folded on her legs. There was a click in the pantry. Nina got up and looked inside. Breakfast had arrived. "We'd better eat something," she told Lucifer. "I am not hungry, Miss Poteil." She brought a plate, and stood resolutely before him. "This is going to be a hard day. You will need the food." He tried to stare her down, but couldn't. He accepted the plate, feeling like a chided school boy. Lucifer ate in silence, and when he had finished, he wandered out into the mossy patio behind the bungalow. There was a milky opaqueness, without obvious form or solidity, that walled the area off from the bungalow on either side. The rear of the patio, facing the forest, was clear, but when he walked too far in that direction, an invisible force shocked him warningly, and he leaped back. The trees were incredibly high; their canopy of branches and leaves was tightly interwoven. The rain had stopped momentarily, but water dripped unceasingly from the canopy to the mat of leaves on the forest floor. Spidery root tendrils crawled upward to mesh with tree boles and hanging vines. There was a smell of eternal dampness. Somewhere back in the shadows, an animal cried out. It sounded like a woman in pain. Lucifer shivered. He wished forlornly that he had left matters up to the FBI and the Central Intelligence Agency. He reviewed his prospects, and did not find them good. In a narrow sense, he had succeeded. He had found his positives and positive positives, but he did not yet know why they had been kidnapped. Nor was it likely that the knowledge would do him much good. He was on a strange planet, in the system of a distant star, apparently destined to spend the rest of his life with a woman who had been a nightclub fortune teller. As a doctor of parapsychology, Lucifer was appalled. As a confirmed bachelor, he was horrified. But a more immediate problem clamored for consideration. What happened to non-positives on Melus? He would soon know. The two attendants who came to take them to Center were much younger than Huth. They carried themselves with military stiffness. Nina and Lucifer were led to what vaguely resembled a motorboat, covered with a transparent bubble. The conveyance hovered in the air, about two feet above a narrow pathway that was surfaced with a dark, burnished metal. Lucifer accepted the vehicle without surprise. Physical scientists had always reminded him of boys playing with erector sets, and their accomplishments bored him. Center was a series of low slate-metal buildings scattered over several acres. Some were inter-connected; some were separated by mossy areas. The outer walls were broken by tall casement windows that extended from just above the ground to just below the eaves. As they circled among the buildings, the casement windows began to swing shut. Lucifer thought at first that this had something to do with their coming, but then he saw the thunder clouds tumbling in over the forest roof and heard the approaching rain. The hot wind swept open a gate as they were rounding one of the opaquely enclosed areas. Lucifer caught a nerve-shocking glimpse of many grotesquely malformed creatures stumbling, sprawling and hopping into the building, under the supervision of several bronzed, statuesque attendants. One creature, with a huge bulging head that flopped uncontrollably from shoulder to shoulder, was bounding along on a single leg. Its twisted features were grimacing horribly. Lucifer did not raise his eyes to Nina's face, but through the transparent sleeves of her tunic, he saw the muscles in her arms grow rigid. The conveyance stopped in front of the entrance to one of the larger buildings. An attendant met them as they stepped out of the vehicle. He led them down a long, glass-roofed corridor. The rain was now drumming dismally against the glass. A blindfolded girl of about six passed them in the corridor. She stepped politely to one side, then continued surely and unconcernedly on her way. Huth received them in a large room equipped with two rows of facing desks. "As I told you," he explained to Lucifer, "these tests will be very elementary. Together with your Earth records, they will form part of your basic family file. And," he added, harshness edging into his voice, "it will be wise for you to give us your complete cooperation." One of the attendants led Nina to a seat in front of a desk. The other attendant beckoned to Lucifer. "If you please," Lucifer said to Huth, "I would like to observe your technique. Being a professional man, you know...." Huth assented. "May I compliment you on your attitude, Dr. Brill. Such an interest can shorten your period of orientation, and it raises my already considerable expectations for you. But we do not pretend to any originality of technique." After watching the attendant run through twenty-five cards with Nina, Lucifer was quite ready to agree with Huth. The technique was crude, far below minimal laboratory standards. Nina's attention wandered about the room, but she called off the cards without hesitation. The attendant took her through three runs, checked his file record and stood up with a shrug. He said something to Huth in a language that blurred and rasped. "Dr. Brill," said Huth, "will you oblige us now?" Lucifer stepped resolutely to the desk, but the palms of his hands were moist. Over the past two decades he had taken many tests, enough to know that he could never score above chance save for an occasional run of coincidence. And this was not one of those runs. He saw it in the attendant's manner before five cards had been turned. Desperately, he fumbled ahead, guessing blindly. At the end of the first run, the attendant spoke rapidly to Huth. Lucifer saw Nina watching him with surprise. "This technique is incredible!" he snapped at Huth. "With all the distractions in this room, not to mention the emotional stress of our situation, a true score would have to depend on chance!" "That is not necessarily so," Huth answered calmly. "The stronger a psi sense may be, the more easily it is brought into use, regardless of external circumstances. You Earth scientists go to incredible lengths to test under laboratory conditions an ability that does not belong in the laboratory." "Ridiculous! Laboratory standards were necessary to prove the existence of psi." "Therefore, Earth scientists will go on proving it to each other for the next hundred years." "What are you proving by this inferior duplication of our psi tests?" Lucifer challenged, hoping to divert attention from another disastrous run of the cards. "More than you suspect, Dr. Brill. For one thing, by checking this first test with your Earth record, and later with additional tests, we can obtain an indication of your response to orientation. This could be important to you, vitally important, I might add. Now, shall we proceed." It was an order, not a question. Lucifer saw Nina nod at him, and try to smile encouragingly. This fed his anger with the fuel of humiliation. The attendant took a new deck of cards, began to turn them. Brill felt his eyes drawn again to Nina. He called out his answer, unthinkingly. "Circle ... circle ... star ... rectangle ... circle...." When the run was completed, the attendant instantly started another. A third and a fourth run, then the attendant turned to Huth with a rapid burst of language. "Excellent," said Huth. "Excellent, Dr. Brill. All you needed to do was relax! Excepting the first run, you averaged very close to your Earth score." Since awakening that morning, Lucifer had found his professional equanimity tried sorely on several occasions. But never more so than at this moment. To have scored so significantly above chance on three consecutive card runs was a greater shock than awakening to find himself with a strange wife on a strange planet. The law of probability was the unchallengeable bastion of his private world. He caught Nina's glance again. Her dark eyes were watching him in a way he could not understand. Huth said, "This has been a most satisfactory prelude to orientation. We can proceed immediately." He touched a button. In a moment, Dr. Thame entered. "You will go with Dr. Thame," Huth told Nina. "Your husband will remain here." Nina looked at Lucifer again, hesitated, then turned away without comment and followed Dr. Thame out of the room. Huth led Lucifer into a smaller office. "This procedure is somewhat unusual," Huth commented. "Ordinarily, new arrivals are assigned directly to units of the Orientation Staff. But we have special hopes and plans for both of you. In particular, Dr. Brill, you can be of great service to us." It was difficult for Lucifer to be anything but forthright, but he tried. "Psi is my work," he said. "I suppose it matters little enough where I work at it. But it would help to know the purpose of all this." "Undoubtedly. But it will not be easy for you." "I am not a child." "No, but you are an Earth scientist." Lucifer felt his anger rising again. "I'm afraid I don't follow you." "I intended no invidious comparison, Dr. Brill. But, as orientation progresses, you will better understand what I mean. Have you ever thought how your science would appear to an extra-terrestrial mind?" "The concept has never occurred to me," Lucifer snapped, thinking of the grotesque creatures running out of the rain, and the blindfolded child walking alone down the corridor. "We see your science as a great number of cubicles, all operating within one structure, with a minimum amount of inter-communication. Each cubicle is engrossed in a process of infinite abstraction from a body of potential knowledge self-doomed to be finite. It studies every new idea chiefly in terms of concepts fundamental to its own specialized body of knowledge." Huth waved a large hand to cut off a protest from Lucifer. "And what of the phenomena an individual scientist observes and evaluates? He shapes the facts into an hypothesis that may be valid only within his own cubicle. He does not venture outside. A most glaring example is that of your medical diagnostician. He uses the tools of his science brilliantly, then lays them down and becomes a therapeutic nihilist!" "Specialization has meant progress," Lucifer protested. "Progress, yes, but progress only to the frontiers of infinity. Will you dare venture into that frontier, Dr. Brill?" "Of course." "Be careful! The price of that venture is very high. Consider for a moment your Earth biologist: The very nature of the subject on which he has founded his science eventually dooms him to technological unemployment! If he follows the living cells to their ultimate sequence of interactions between ions and molecules, biology ends as it began--as applied chemistry and physics!" Lucifer shifted uneasily. "From another value judgement," Huth continued, "the orthodoxy of Earth science is a product of its fragmentation. Within each cubicle, isolated from the fertilization of new concepts, the unorthodox all too often and too soon can become rigidly orthodox. This is the circle around which each science seems forever to travel!" Lucifer felt himself being moved skillfully toward an unknown objective. It was like being a Knight on a chessboard in the hands of an expert player. Huth moved in closer to his objective. "And so it is with psi, Dr. Brill. Or so it appears to an extra-terrestrial viewpoint, which is now necessarily your own! Parapsychology had to depart from the physiology of orthodox psychology in order to get a look at itself. It became unorthodox avant guarde! It established a scientific case for psi, and for two decades thereafter established little else. What have you proved that Rhine did not prove twenty years ago?" "It is necess--" "Already we see forming a dogma of psychic research, a cult of psychologizers that may match in exclusivity the cult of physiologizers--each declining to draw upon the resources of the other! We see a tendency to look backward instead of forward, a bemusement with the historical concepts of association theories, psychon systems and continuums of cosmic consciousness--all of which suggests a turning away from the frontiers of infinity to an interminable abstraction of possibilities from your own finite knowledge. "Do you follow me, Dr. Brill?" Lucifer removed his glasses, breathed on them, polished them carefully on the sleeve of his tunic. He looked beyond Huth to the window and the steaming tropical rain. When his thoughts were composed again, he answered, "I follow you--with reservations." "Naturally. Now consider this question: Have you looked into other cubicles of science for answers to psi?" "We welcome all viewpoints." "Do you now? I wonder! From our extra-terrestrial viewpoint, it is evident that biology, chemistry and physics all have within their present finite bodies of knowledge the fragments of concepts that could propel psi, and hence all of science, into the very frontier of infinity." Huth paused, looked searchingly at Lucifer. "Dr. Brill, are you ready to share your primacy in psi research with the physicial scientist?" "The physical scientist scoffs at us." "He also is reluctant to leave his cubicle. However, by using the mathematical tools of logic to enclose psi research in a framework of anti-logic, built on the principle that man cannot know, your psychic theorist has alienated the handyman physical scientist who has so much to contribute--but who insists that man must know." Huth raised himself to his magnificent seven feet of height. "Let the thoughts germinate, Dr. Brill. This is only your first orientation session. On the whole, we have made good progress." He handed Lucifer a printed card. "This will instruct you how to tune in your visagraph to a closed circuit orientation program after the dinner hour. Do not fail to follow instructions." With the briefest of nods, Huth stalked toward the door, where he turned, as if in response to an afterthought. "Your motivations to progress in orientation will be several, Dr. Brill, but it may be well for you to know that you already have a hostage to the future success of our program." "Hostage?" "Your first child, Dr. Brill. It will be born in approximately seven Earth months, according to the calculations of Dr. Thame. "Meditate on this while you await the attendant who will return you to your quarters." * * * * * Lucifer tried to square his thin shoulders against the straight-backed chair. He ran the tips of his fingers over his upper lip, and out of the numbness that gripped his brain came a vagrant thought: His mustache really did need trimming; it wouldn't do at all to let down about such things. The door clicked open. He turned, expecting to see one of Huth's attendants, instead he faced Nina. Her cheekbones made two spots of white against her olive skin. "Hello, Lucifer," she said. Her voice was even deeper, huskier than usual. Her tone and the way she used his first name told him she knew about the child. But he pretended not to notice. He couldn't discuss the child until he had time to evaluate the meaning of it all. "Miss Poteil," he began firmly. His voice shook a little, and he started again, "Miss Poteil, I trust your first orientation session was not too unhappy an experience." Her dark eyes were thoughtful, troubled. "What is unhappiness?" She shrugged in reply to her own question. "I am never sure about crossing the line between happiness and unhappiness. Are you?" She sat down facing him. "Is your question philosophical or psychological, Miss Poteil?" She smiled faintly, and shook her head. There was silence between them. Finally she spoke again, "I saw the little girl as I came in." "The girl with the blindfold?" "Yes. She stepped right past me, and went into a room just down the corridor. The room seemed to be full of children." Lucifer stood up with sudden decision. "I believe I will try to look around." The white spots grew in her cheeks. Her full, expressive lips tightened. "Be careful, Lucifer," she said quietly. The long corridor was frighteningly deserted. With so many doors opening off it, the odds seemed overwhelming that someone would step out one of them at any moment and challenge his right to be there. Lucifer's plastic boots scraped on the metallic composition floor. A subdued tinkle of children's voices drew him to a door some thirty steps down the corridor. The door appeared to be of a glass-like material, but it was opaqued. He pushed against it, and it moved. He drew a long breath, then inched the door open. A tall, bronzed women of Huth's racial characteristics was grouping a dozen or so youngsters into an activity pattern. The children were all around five or six years old. Their fair skin and bone structure indicated they were offspring of Earth parents. The woman blindfolded one of the youngsters, a square-shouldered, blond little fellow. The she tossed a ball to one of the other boys, and gave a short command in her own language. The children scattered about the large room. The boy with the ball ran and stood against the window, which was blurred from the driving rain. After chanting what appeared to be a number count, the blindfolded boy began to move around the room. As he approached one child after another, he would hesitate while still three or four steps away, shake his head and move on to someone else. Finally, when still some ten feet from the window, he swerved abruptly toward the boy holding the ball. He ran directly to him, grabbed him by the arm, then fumbled for the ball and clutched it triumphantly. The other children broke into an excited babble, and everyone seemed to be clamoring for the next chance to be blindfolded. The woman looked disconsolately at the rain-streaked window, and began to blindfold another child. Lucifer eased the door shut. He moved on down the corridor, past room after room that seemed deserted. A tentative testing of several doors proved they were locked. Near the end of the corridor, where it turned at right angles and headed down an equally long wing of the building, Lucifer found another room that sounded occupied. Again he inched the door open. This room was occupied by smaller children, mostly of prenursery school age. They were playing a version of a game Lucifer recognized from his own childhood: Tail on the donkey. Only this donkey was a sinister looking creature with tiny ears and formidable jaws. One by one the children toddled up to pin a stubby tail on his derriere. Three of them hit the target with biological exactitude. The fourth missed badly. It was a little girl. When the others laughed, she tore off her blindfold, stamped her tiny foot. A bench sailed across the room, thudded flatly against the opposite wall. The children's derisive laugh changed to one of excitement, and the girl felt encouraged to expand her tantrum. The bench caromed from wall to wall to ceiling and off, with a crash, into a corner. The woman attendant picked up the child by the shoulders and shook her. For an instant, wild defiance flared on the childish features. Then the girl pouted, and two tears trickled down her soft cheeks. Lucifer didn't try to analyze his impressions. There would be time for that later. Now it was important only to gather as many facts as possible before he was detected. The second corridor contained many rooms. From the sound of the voices coming through the doors, and from spot-checking several rooms, Lucifer judged they were all occupied by children engaged in some form of play activity that required psionic ability. At the end of the corridor, Lucifer opened a door and found himself staring out into the rain. Urged on by a growing eagerness to learn as much as he could before he was stopped, he ducked outside and ran across a mossy stretch of courtyard toward a second building. Rain plastered his hair, and trickled down his neck, but his tunic and leggings seemed waterproof. The rain was hot and stinging, and the wind surged out of the forest with lashing force. Half-blinded, Lucifer stumbled over some unseen object. He sprawled to his knees. He got up, slipped again, and skidded into the partial shelter of a doorway. The door couldn't be moved. Lucifer moved out into the rain again, and groped his way along the side of the building. He stumbled over something else, fell heavily. A hoarse outcry, lifting above the wind and the rain, brought him to his knees. Shielding his eyes, he saw that he had stumbled over a figure huddled in a corner of the building. The figure straightened above him. Its movements were jerky, like a carpenter's rule unfolding. It was one of the grotesque, misshapen creatures Lucifer had glimpsed on first approaching Center. Through the slanting rain, Lucifer could make out a gigantic head that bulged sickeningly and was utterly devoid of hair. The head sagged forward, flopped back again until it struck the wall of the building, then snapped forward. It had two blank eyes, a flattened horror of a nose, a mouth that sagged and twitched. The mouth was trying to say something, but the words dissolved in a bubble of red saliva and a merciful wash of rain. The head flopped back and forth. The figure jerked toward Lucifer, lunged and fell on top of him. For the first time in his adult life, Lucifer lost control of himself. He screamed, and screamed again. * * * * * Hands clawed him down, smashed his face into a choking puddle of water and wet moss. The hands and arms beat against his back and ribs. Each blow was a flailing, uncoordinated effort, but the impact was crushing. Water bubbled into Lucifer's mouth and nostrils. He raised his head to breath, and a random blow smashed it back down. He gulped air and water together. He choked, strangled. And then the weight was gone from his back. The hands and arms stopped smashing against his flesh and bones. Lucifer raised himself on his elbows, retched chokingly. A powerful pair of hands picked him up and half carried him out of the rain. Someone brushed back his hair, wiped his eyes. He opened them. A tall attendant held him up. Nina dried a trickle of water from his cheek. Her dark features showed shock and concern. Huth watched him sardonically. "It was fortunate your wife sensed your danger and helped us find you," Huth said. "Your zeal for orientation is commendable, Dr. Brill, but I suggest you proceed less rigorously." Lucifer took the handkerchief from Nina, wiped his mouth. It tasted salty. He attempted to stand with some measure of dignity. "Who or what was that creature?" he demanded. "I think you have had quite enough orientation for the time being," Huth replied. The strange conveyance whisked them back to their bungalow. Lucifer soaked himself in a hot bath, and it was a long time before his trembling muscles relaxed. Dinner, via the tubicular, consisted of a meat dish, more strongly flavored than venison, two rather salty green vegetables and a flagon of warm, spicy amber liquid. They ate in silence. Soon after dinner, Huth appeared on the visagraph screen, for what he called their second orientation session. This was largely a development of the first, and so were those that followed on succeeding days. Each left Lucifer feeling more unsure of himself, tense, mentally adrift. The distance between Melus and his safe, secure little laboratory at Western University was becoming greater than could be measured in light years. Ranging from geology to biochemistry, from physio-psychical sources of neurosis to what he called the "molecular site of understanding", Huth hammered incessantly with semantics and logic against the carefully mortared bricks of Lucifer's own scientific cubicle. Sometimes he spoke with almost mystical fervor of a frontier beyond a frontier, a science beyond a science. One evening, during a visagraph session, Nina suddenly interrupted: "Your words speak about the infinite," she murmured, "but your mind does not sing with the music of infinity." Now, for the first time, Lucifer saw uncertainty on Huth's face. Uncertainty, and a look of indescribable sadness. Then the visagraphs screen went dark. Nina was on the couch beside Lucifer. Her eyes were half-closed; her strong fingers were clasped around her knees and she rocked back and forth gently. "What a strange man," she said. "What a strange and strong and lonely man. For a moment, I saw all the loneliness of the universe in his eyes...." Lucifer regarded her uneasily. "You see many things, Miss Poteil." "No, Lucifer, I see so very little. But what little I do see makes me feel like a blind person the rest of the time. Isn't it terrible to look at shadows?" "Really, Miss Poteil--" "Hush!" She put her finger to his lips. He started. "Wha--?" "Please, Lucifer--Oh, be quiet--Please!" Her breasts rose and fell sharply beneath the thin tunic. He saw the tendons stand out in her throat. Finally she whispered: "I think someone is coming to see us! Tonight. I'm not sure.... Oh, this damned blindness!" She beat her fists furiously on her knees. Lucifer tried to speak casually: "If someone comes, we'll know about it soon enough. Meanwhile, I suggest we try to get some sleep." There was a strange weariness in her as she got up from the couch and started toward the bedroom, which Lucifer had sternly assigned to her after the first morning of awakening. But after a few steps, she stopped and turned back to him. "Lucifer, they say you are the father of my baby. If that is so, I am grateful." It was the first time they had mentioned the child. Lucifer felt shocked, and very humble. This was another new feeling. He decided it would be wisest not to speak. "You are a man, Lucifer," she went on, in her husky voice. "I knew it when you tried to take that test, knowing you would fail." She brushed her lips across his forehead. "Goodnight, Lucifer. I have known many males, but very few men. There is a great difference...." He lay awake on the couch for a long time, his body aching for sleep, his mind spinning with strange thoughts, stranger concepts. He was just beginning to slip into the twilight zone between wakefulness and troubled sleep when a foreign sound in the room jarred him awake. Forcing himself to lie completely still, to continue his even breathing, he strained to catch a repetition of the sound; his eyes turned toward the rear window. The latest rain squall had swept by, and the window was now a luminous rectangle against a brilliant, star-filled sky. As his vision cleared and focused, he saw that the casement window was partly open. A fresh breeze, warm and fragrant with the odors of the rain forest, swept across the couch. Lucifer heard a definite, sharp click from the visagraph. It was as though a switch had been snapped. But there was no shadow of a physical presence in the room. The bedroom door opened suddenly. Nina stood there for an instant, silhouetted in her short, white nightgown. Then she moved quickly across the room, knelt beside his couch. Her lips, warm and dry, pressed close to his ear; her long hair tumbled over his cheek and throat. She whispered: "Can I stay here a little while?" He nodded, and felt her body crowd against him on the narrow couch. They lay there together, breathing quietly, watching the open window. And then there was a shadow there, a darker something against the darkness. Nina's body stiffened. With an unconscious gesture older than remembered time, Lucifer put his arm over her. A voice spoke out quietly from the window. "It's O.K. now, Dr. Brill." * * * * * A figure stepped through the window, stumbled over the hassock and sat on the edge of it. "You both there?" a man's voice asked, then, without waiting for an answer, continued: "... Good!.... Fetzer's my name. Albert Fetzer. Remember me, Dr. Brill?" "I regret to say--" "That's O.K. It was a long time ago--when I was GI-ing my way through electrical engineering at Western. You gave me a lot of card tests. I did pretty well, too--damm-it!" "I'm sorry." "None of us blames you anymore. We were kind of bitter at first--now we're glad you're here." "Glad?" "Sure. We've got a lot of things figured out, but there's still a lot more we don't get. You could be a big help to us." "I sincerely hope so, but--" "But, nothing, Doc. It looks like they're really giving you the orientation business--like they need you and are going all the way this time!" Lucifer's tongue felt dry, and difficult to maneuver. He was grateful that Fetzer didn't seem to expect an answer. "They've been cozy with some of us before, but always cooled off. You just play it smart, learn all you can! But be careful, or you'll end up with the _Goolies_." Fetzer listened intently, then chuckled. "I guess they're still kind of fouled up! We had to warp the force field behind your place--shorted their magnetic track, too! But before they get here there's something else I've got to warn you about--'specially you, Mrs. Brill." He hesitated. "What is it?" Nina prompted. "Well, when you think you get a message from us don't bust out with it like you did a while ago. They pick up everything you say on that damn visagraph--I had to short the magnetic track in order to get at the control wire to block it off--" "Just a moment, Albert," Lucifer interrupted. "How did you know what was said in this room?" Fetzer sounded embarrassed: "Well, it's a funny thing, Doc, but back on Earth we were all kind of ashamed of this psi thing. We tried to keep it hid from other people. Here, it's different. We're all the same way, more or less. So we try to use psi instead of hide it. Doesn't work on Huth's gang, though. They got minds like machines--It's like trying to psi into a quarter-horse motor!" There was a pounding of footsteps outside the front door. "Gotta go!" said Fetzer. He twisted lithely through the window, closed it behind him and vanished into the sultry night. Nina slipped from the couch and hurried into the bedroom. The front door banged open. The room light flared on, blinding Lucifer. Huth was there, with two of his men. The men ranged about the place with giant strides, going through the living room, the bedroom and out into the rear enclosure. One of the men worked on the visagraph, trying to light it up. He had no success. Huth stood over Lucifer's couch. "Has anyone been here?" he demanded sternly. "If there was, he was more quiet and courteous than you have been," snapped Lucifer. "Need I remind you that this has been a most exhausting day, and that to be awakened in this manner--" "Mrs. Brill received a message, and informed you of it." "Miss Poteil talks a great deal of nonsense, which you must also have overheard. However, I assure you, Sir, that I am not interested in her hallucinations, and if you are, I suggest you discuss them with her in the morning." "What happened to the visagraph." "If I knew, I wouldn't care. Your electronic gadgets impress me as being rather juvenile." Huth bowed. "Perhaps because you do not understand them, Dr. Brill." The warning in his voice was clear. He turned sharply on his heel, motioned his men out of the room and left, shutting the door quietly. * * * * * With breakfast, the tubicular delivered a metal-backed manuscript that bore the scholarly title: "Genetics and Psi, with an Evaluation of Three Case Histories as Compiled from Earth Records." Nina glanced at the title across the breakfast tray, then shifted her chair beside Lucifer's. "I'd better read that, too," she said. "Maybe it will tell us something about our own genetics experiment." Lucifer pursed his lips in disapproval at her frankness, but he held the manuscript so that both could study it. The introduction began: "After studying the incidence of psi on Earth, we felt that the genetics approach should receive considerable concentration of effort. Our chemists, biochemists and physicists are naturally continuing their experimentation, but the geneticists seem to promise the maximum results in the minimum amount of time. If psi can be explained, understood and propagated through genetics, it can no longer be mis-nomered 'extra-sensory'. It will become no more 'extra-sensory' than sense of direction, sense of time and, in the case of musical aptitude, such component primary senses as sense of absolute pitch, sense of intensity, sense of harmony, sense of rhythm and sense of tonal memory. Thousands of tests have indicated that these musical senses may have an hereditary base." "Physiologizers!" Lucifer exclaimed, contemptuously. "Let's keep our windows clean," Nina murmured. He stared at her in surprise. "My father used to say that," she explained. "He told us to keep our windows clean--so truth can look in and out." Lucifer turned back the manuscript. He felt somehow chastened. After several paragraphs of further discussion on the hereditary aspects of the various senses, even including the inheritance through a dominant gene of the ability to taste, the manuscript went into a long analysis of the family trees of Arturo Toscanini, Kirsten Flagstad and the 19th century mystic, Daniel Dunglas Home. "Please note," the manuscript emphasized, "that in all three family trees a favorable heredity and a favorable environment were perfectly blended." Nina gasped excitedly. "Oh, Lucifer--if this project can bring the right parents together...." "Human beings are not white mice!" Lucifer snapped! "They are on Mendel's Planet!" Nina seized his hand. "Think, Lucifer! Our child may be able to see things we have never dreamed of seeing! We will teach him to use his eyes from the very moment of birth--even before!" Deep anger and resentment stirred within Lucifer, but before he could answer her, a click from the visagraph screen told them they were not alone. Huth's usually calm voice betrayed his excitement. His dark eyes glowed. "Mrs. Brill--how would you propose to train a child so early?" "By encouraging him to use his own true senses rather than his superficial senses for his very first needs! My father raised all six of us and he used to say I was a good baby, because I never cried to be fed or changed. But maybe it was because he knew what I wanted and took care of me before I cried!" Huth insisted on sending for them immediately. There was a three-day-old Earth child at Center. Huth had the baby's records before him when they arrived. Nina, flushed with eagerness, asked: "How is the baby fed?" Huth consulted a chart. "Both formula and breast. But it doesn't appear that the mother will be able to nurse much longer." "When is the next feeding time?" "In approximately one hour." Huth took them to the nursery. Through the window, they could see that the baby was still asleep. The young mother was sitting up in her room. A tiny, thin-faced woman, she looked at them with alarm. "Is something wrong with my baby?" Nina knelt beside her chair. "Don't you know your baby is all right?" she asked gently. "I--I thought so. But when you all walked in like this, I wasn't sure." Lucifer didn't recognize this young woman; nor did she appear to recognize him. Her eyes, still dilated, roved apprehensively from face to face. "You're not going to do something to my baby?" Lucifer felt a great pity for this young woman, snatched away from Earth to bear a child with an unknown mate on this strange planet. "I wouldn't harm your child," Nina told her. "I'm from San Diego--how about you?" "Masselon, Ohio." "Now tell me," Nina asked, "is your baby awake yet?" The dilated eyes stared at Nina. "I'm ... I'm not sure, but I don't think so." "That's fine. Now, please don't be scared. I want to help you and your baby. Do you trust me?" The young mother studied Nina unblinkingly. After an instant of hesitation, she nodded. "Thank you. Now, are you going to feed your baby yourself this next time?" "I'll try again; but I haven't been doing so well." "Can you tell when your baby is starting to wake up?" "I thought I could the first day or so. But then I didn't try--I guess I got used to having my baby brought to me every four hours." "Is the baby usually crying when it is brought into the room?" The young mother smiled. "Oh, yes! She's got a strong, healthy cry!" "Will you try to feed her this time before she cries, when she first tells you that she is hungry?" "What--what do you mean?" Nina took the young mother's thin hand between her strong, brown fingers. "You know what I mean! Don't be afraid to use what God has given you! Let's stop talking now so you can keep your thoughts with your child!" Under the dominance of Nina's personality, the woman settled back in her chair. Outside, the first rain of the morning swept over the forest and steamed up the windows. Huth stood statuesquely by the door, arms folded. The tall nurse remained watchfully beside him. Lucifer struggled with an unaccustomed inner turmoil. Dissecting the tangle of his emotions, he was astonished to realize that his pulse was thumping with excitement. Abruptly, the young mother spoke up. "My baby is hungry. She wants to be fed." "Go feed her then!" commanded Nina. She helped the young woman from the chair. Together they led the way down the corridor. As they neared the nursery, Lucifer edged closer to them. He saw that the child was still asleep. The mother saw it, too. "But she's still asleep!" she said, bewildered. "I thought--" "Does a child have to be awake to tell of its hunger?" Nina asked gently. The young mother went ahead of them into the nursery. She took the child from the crib and cradled it in her arms. The baby stirred, grimaced. Its lips groped in small, sucking motions. The young mother hesitated, then opened her robe and brought the baby's lips to her breast. The child began to feed contentedly. At a gesture from Nina, the others left the mother and child alone in the nursery. When they were well down the corridor, Nina burst out triumphantly, "The first contact! Child has communicated to mother. Message received and answered. Child has used primary sense of communication, rather than learning to rely on secondary!" Nina squared her shoulders proudly. "My baby won't have to cry to tell me that it's hungry or cold or wet and miserable!" Lucifer's New England conscience prodded him. If indeed there was anything to this psi heredity business, then he had again hurt someone else, unknowingly, but deeply. What would Nina say and feel when she learned that he had no psi talent to pass on to their child? But this uneasy remorse conflicted with another emotion in Lucifer: The sense of excitement that he suddenly realized had been lost somewhere back in the early years of his psi testing. Somewhere, sometime along the way the sense of wonder had gone out of his work and his life. The constant repetition of the same basic testing technique had made a familiar backyard out of--what had Huth called it?--the very frontier of science. Huth was speaking to him. "What do you think now, Dr. Brill? Could it be possible after all that the unorthodoxy of Earth's parapsychology might have to be shaken from its own orthodoxy?" Lucifer frowned. "I do not want to split definitions with you. But it should be obvious to any scientific mind that Miss Poteil's experiment, although interesting, was painfully inadequate in methodology. In the first place, can we determine whether the child was communicating a need, or whether a psi-positive mother had some precognition of her child's need? In the second place, would a large number of children born of psi-positive parents react with significant difference from a similar number of children born of psi negatives?" "A flash of lightning can be duplicated in the laboratory," said Huth, "but it is still a flash of lightning. We recognize lightning, we admit its existence, but we do not wish to go on proving forever in the laboratory that lightning is in fact lightning. If some of your earlier scientists had been content to do that, your cities would still be illuminated by oil lamps." "A fallacious comparison!" "Not entirely so! I merely wished to make a point. It is all a matter of objective. You have seen how older children are developing their psi talents in our classes. Your wife may have shown us how to begin training at a much earlier age, when training is most important." "Still, I should think you would require more substantiation, some further testing, to support Miss Poteil's little experiment." "Of course. Do you have any suggestions, Dr. Brill?" Once more Lucifer found himself backed toward a corner. Only this time he did not try to escape. The challenge intrigued him, in spite of his determination not to become involved with this nonsense. A controlled experiment was quite a different thing.... "I might have," he replied, with an effort to be casual. He plucked at his mustache. "But you must grant that a valid basis for experimentation cannot be improvised on the spur of the moment." "Improvise at your leisure, Dr. Brill." Nina was sent off to continue orientation work with Dr. Thame. Lucifer was given a small cubicle near Huth's office. It consisted of little more than a desk, a stool, three bare walls and a floor to ceiling window through which an orange rim of the planet's great sun was now shining mistily. Lucifer scribbled notes, drew crude diagrams, tore them up and started all over again. Spots of color flushed his cheeks. Though he would not have made the admission, he hadn't enjoyed himself so much in fifteen years. He didn't even notice when a new squall rustled across the wet jungle, blotting out the sun and drumming against the window. Huth came in with the attendant who brought lunch. "How many children are there here now?" Lucifer asked crisply. "I believe we have about thirty under the age of nine months." "Do you have another nursery room, like the one we visited this morning?" "We have three more in the Maternity Division." Lucifer explained his immediate needs. Huth issued orders that three more babies be brought to the Maternity Division. Each was installed alone in a nursery. Two were placed in cribs, and soon fell asleep. The third, a boy of about eight months, refused to nap. He wasn't happy until allowed to crawl around the floor, exploring the strange wonders of the nursery. Lucifer made a quick procedural adjustment, and hoped the youngster would stay awake until feeding time. He tried to tell himself, whenever he thought about it, that he was doing all this only to point up the absurdity of Huth's theories. As feeding time neared, three bottles of heated formula were brought in warmers and placed at Lucifer's direction in rooms immediately adjacent to each of the nurseries. Two of the children were still asleep; the third had discovered a pack of disposable diapers and was systematically tearing it apart. Dr. Thame joined them to watch the experiment, and he brought Nina along. Her eyes sparkled with interest and understanding as she watched Lucifer's preparations. After one quick nod, he did not look her way again, and he stifled the thought that Nina would be watching the experiment with their own child in mind. One of the babies stirred in its sleep, and whimpered a little. "Normally," explained Dr. Thame, "a child of this age would awaken shortly and begin to cry." The baby squirmed again, then turned toward the room in which one of the bottles had been placed. Its tiny lips worked in a sucking motion. "How wonderful!" whispered Nina. Lucifer picked up the bottle, moved slowly into the corridor. The child appeared confused. Its eyes screwed up tightly, and its face reddened. Then it jerked its head toward the new position of the bottle and repeated the sucking motion. Nina, who had followed Lucifer, squeezed his arm in excitement. He gave her the bottle, and she hurried into the nursery to reward the child. Its lips groped eagerly for the nipple. By this time, the second child was stirring. Its reactions were much slower, and more uncertain, than those of the first baby, but they followed the same pattern. Nina went on to the third child, which had been left playing on the floor of the nursery. "Lucifer! Come quickly!" she called. The child had crept over to the wall nearest the room in which its bottle had been placed. It was pawing, bewildered, at the rough surface. Ducking below the window edge, Lucifer picked up the bottle and moved it to the other side of the room. For a moment the child looked like it was about to cry. But it hitched around on its knees, sprawled flat, raised up again and crawled across the floor. When it was midway to the other side of the nursery, Lucifer switched the bottle back to its original position. The child continued its forward progress for a few feet, faltered and stopped. Its red button of a nose wrinkled, and two big tears squeezed down its round cheeks. Nina rushed into the nursery, picked up the youngster, cooed over it and thrust the nipple of the bottle between its anxious lips. "My compliments, Dr. Brill," said Huth. "Does this begin to satisfy your laws of probability?" Lucifer was determined not to show his excitement. He shrugged. "Five thousand more tests might prove something--providing you counterposed 5,000 tests on children whose ancestry was psi negative." "We're not interested in psi negative children, Dr. Brill." Lucifer faced him squarely. "Just what are you interested in? I think we are entitled to an explanation." Huth hesitated, then nodded. "Perhaps you are." * * * * * When they were settled in Huth's office, he stood by the window and folded his huge, bronzed arms. "My home planet," he began, "is also in the system of Capella. We are an old race, but neither decadent nor degenerative. Our physical sciences--as you can judge from your presence here--are at least 500 orbits beyond the outermost probings of science on Earth." He paced across to the door, and back to the window again. "But in our obsession and fascination with the ever new horizons of physical science, we neglected that which was potentially of far greater significance. We ignored the possibilities of psionic evolution--we ignored them until it was almost too late!" "Too late," breathed Nina. "Is that why your mind feels like a machine?" Huth inclined his massive head in her direction. "That could be why, Mrs. Brill. What society--or our bodies--neglect will eventually die. It is true even of psi, Dr. Brill." "Can you be specific?" Lucifer challenged. "I can. If you had taken your eyes out of the laboratory long enough to look at your world as it is and has been, you would have learned that psi manifestations were quite customary on Earth during the 13th and 14th centuries. But your industrial age did not have much room for psionics. With Daniel Dunglas Home went the last of your great psi talents!" "Our card tests have discovered many psi positives," Lucifer interjected heatedly. "You ought to know--you have many of them here now!" "Psi positives with thwarted, arrested or frustrated talents," replied Huth. "Psi positives who wanted to be 'normal', because that is what society demanded.... Psi positives who were ashamed of their talent and quite willing to have it overlooked! Yes, we have them here ... and, what is more important, we have their less inhibited children!" "Your logic escapes me." "It wouldn't if you had emerged from your cubicle and looked around you among the physical sciences. Some of your more venturesome geneticists believe that man will soon be the master of his heredity and that the next five million years of evolution on Earth will be the controlled evolution of the human mind. That could mean controlled evolution toward psi, Dr. Brill--if Earth science can ever escape the terrible drag of orthodoxy and if the unorthodox can ever learn to avoid the trap of its own dogma." Nina had been watching Huth with the unblinking intensity that was so characteristic of her in moments of total concentration. "So we are your nursery!" she exclaimed. "We produce the plants that will bring life back to your own soil!" Huth came close to one of his rare smiles. "You have admirably reduced the milleniums and mathematics of evolution to a single sentence!" He turned to Lucifer. "Is this a laboratory big enough to challenge you?" Lucifer took refuge in a question of his own. "What about your _Goolies_?" From the shadow on Huth's face, and the faint gasp from Nina's parted lips, Lucifer knew he had made a mistake. "Where did you learn that name?" Huth asked him coldly. Lucifer was not a good liar, but he tried. "I--I don't really know. Perhaps--from one of your nurses or drivers...." "We will accept that explanation, for the moment. Later, I trust you will volunteer another." Huth's emphasis on "volunteer" was almost imperceptible, yet it had the effect of two pieces of steel striking together. "You have already met one of these--_Goolies_. Let us go and meet some more." Nina put out her hand. "Is this necessary?" Huth regarded her thoughtfully. "Yes, I believe it is. If we are going to work together, you should know everything." "And if we're not?" Lucifer snapped. Huth shrugged. "Then it won't make any difference, I assure you." Outside, the wet moss of the courtyard was springy underfoot. Lucifer flinched with the remembered horror of trying to breath through that moss and water. Nina took his hand. Her fingers were strong and warm. A tall attendant let them into the building. Lucifer looked down a long, sterile-white corridor, flanked by small, seemingly transparent doors. "The doors are transparent only from this side, and then only when subjected to the proper wave frequency to make them so," Huth explained. "Like the rooms we live in!" Nina burst out. Huth blinked, and assented, "Like the rooms you live in." Before Lucifer could assimilate this bit of information, Huth had stopped before the first door. Inside was a shrunken monstrosity of a creature. It had the torso of a grown woman, but its legs were bone thin, twisted and scarcely eighteen inches long. It was hairless; its face was one ovular blob of flesh, in which the eyes, mouth and nostrils were knife-edge slits. It seemed to be watching the rain-streaked window. There were two beings in the next room, apparently male and female. Both were naked, and seated cross-legged on a thick mat. They were playing a complicated game with marked and colored blocks. The woman's body was covered with a fine, brown hair. Her breasts were tiny for the dimensions of her body. Her head was also small out of all proportion, as was the male's. Lucifer saw that though both were eyeless they were playing their game rapidly and skillfully. Their hands were lumps of flesh, with just rudimentary fingers. "They are quite sentient," Huth observed. And he added with pride, "You would classify them as definite psi positives--altogether our most successful experiment of this type!" As they neared the next door, it suddenly became opaque. Huth led them past it without comment. Nina winced, and her fingers tightened convulsively. They were led quickly down the rest of the corridor. Some of the doors were opaque. Through others, they caught glimpses of more grotesquely distorted creatures, some asleep, some lurching or crawling about their rooms. The corridor ended in a large multi-purpose type of room in which semi-human creatures of all shapes and sizes were milling about. Huth opened the door. "Go on in," he said. It took all of Lucifer's will to control his revulsion and trembling and step through that door. Nina followed. Her fingers rigid in his hand. One of the creatures nearest them turned nimbly around on one leg and hopped closer. It reached out a long arm, touched Nina's forehead. A harsh, croaking sound came from its mouth. Nina's lips quivered, but she smiled and patted the leathery hand. Others bounded and crept around them, jibbering, feeling their faces and hair, probing at their bodies with stumps of arms or with hands that seemed all fingers. "All of these people show some traces of psi," Huth explained. Again there was quiet pride in his voice. A wracking cry came from one corner of the room. A huge shape hurtled into the group around them, knocking others out of its way. Lucifer saw the wildly flopping head, then long arms reached for him and a crushing weight bore him to the floor. There was a choking odor of hot, oily flesh. And then the weight was gone. Two attendants led the creature, still mouthing angry cries, out of the room. Huth helped Lucifer to his feet. "You must forgive Tetla. He shows up well in some basic psi tests, but certain other faculties were lost in the manipulation of his chromosomes. We never quite know what he will do." The other beings had fallen back in silence during the assault. Now they began to babble in wild disharmony, each gesticulating in its own way. Lucifer's cheeks were grey, but his lips were compressed into a thin line under the stubble of his mustache. He took Nina's arm and strode out of the room. Huth followed, without comment. Out in the corridor, Lucifer confronted him. A sweep of his arm encompassed the long corridor, the room they had just left. "This--this is a monstrous inhumanity--a terrible perversion of science!" His voice was flinty with rage. Deep within him, the conscience of his puritan ancestry was revolted. Huth raised an admonishing hand. "Don't forget your scientific training, Dr. Brill. You can't impose the value judgements of one culture upon the framework of another." "There must be certain principles basic to all cultures!" "A true Aristotelian fallacy! Form is actual reality, matter is potential reality and the form is ever in the matter! Surely, Dr. Bill, you can rise above such ontology!" "Can you justify what you have done to these people even from your own value judgement basis?" "You treat justification as a valid entity, which leads you deeper into the morass of attempting to substantialize abstracta. We do not justify, we do! Let me clarify: "With the future of our evolution in the balance, with the unbounded horizons of the universe that will be opened by psi, we have taken certain measures. Once we postulated the genetic characteristics of psi, there was no limit to possible methodology. You have seen only two of many methods we are exploring: One, of course, is the Earth project; the second is an attempt to induce psi mutations in the offspring of certain of our own people. Naturally, since the external results of such experiments are often unpleasant, we bring the newly born infants directly to our laboratory on Melus." Nina's eyes were still wide with horror. "How do you do this thing?" "Really, Mrs. Brill, it's nothing to be so shocked about. As a matter of fact, it's only a further step in what your own experimenters do by exposing Drosophilae to X-rays and plants to colchicine. We are endeavoring by many methods not only to mutate a gene by re-arranging the atoms in its molecules, but also to increase the quota of chromosomes in certain cells. The difficulty, as yet, is to single out the right string of chromosomes or to hit the right gene and influence it toward the desired psi mutation. We are still groping in the dark, simply increasing the chances that one or another gene, at random, will psi mutate." As Huth spoke, he had been leading them toward a side exit. A vehicle was waiting. Huth put his hand on Lucifer's shoulder. "We did not bring you to Melus, Dr. Brill, merely to reproduce your own psi characteristics. We feel that your background will enable you to make many notable contributions, once you become oriented. Already you have justified this feeling. Your people will do things for you and Mrs. Brill that they would not willingly do for us." "I want nothing more to do with this project." "I am sure you will recognize your present reaction as purely emotional, and come quickly to realize that here you have the answer to a true scientist's dream--a laboratory on the scale of life itself! For twenty years you have taken timid steps around the periphery of your science. Now you are at the heart of it!" * * * * * What should he think? What should he believe? What should he do? Lucifer walked slowly around the small clearing behind their quarters. He stared, for the most part unseeingly, through the force field and into the shadows of the forest. His shoulder brushed the invisible barricade, and the shock broke the rhythm of his stride. What should he believe? This question bubbled most frequently to the roiled surface of his thoughts. With belief would come the mental framework, the pattern for action. It was disturbing and confusing that credo should be so important to a scientific mind. Couldn't facts take form without credo? Did facts shape the framework, or were they molded to conform to it? Einstein made truth relative to its own framework, but which came first--the framework or the truth? And if the answer was framework, could there be truth? Perhaps the childhood riddle of the chicken and the egg could have cosmic implications. A vagrant phrase from a long-ago literature class came back to prod him now: To an egg the chicken is merely the means of producing another egg. Samuel Butler. A shaft of sunlight speared down through the whispering canopy of branches high above him. It kindled to life a spot of riotous color in the perpetual shadow world at the base of the great trees. Blossoms of delicate blue, petals flecked with orange and gold. Leaves so green they brought an ache of loneliness for a forgotten spring morning of youth. What should he believe? With sudden percipience, Lucifer knew that he had moved in the shadows for a long time. The riotous dreams of youth, the exciting sense of being a pioneer among pioneers, had become like a bit of stop-motion film. It preserved the form, without the life or action. A dream cannot be framed and kept behind glass. It cannot be static. To remain, it must change. Parapsychology had been the high road. The glorious adventure. It had made the son of a New England minister an explorer on a new frontier. But does a frontier of science have purpose other than to lead to an infinite succession of new frontiers? Had he remained too long on one frontier? The unorthodox becomes the orthodox. The theory crustifies into the dogma. The method becomes methodology. Was this forever to be the entrapment of science? There were an infinite number of exploratory possibilities on this frontier of today; and, for all their challenge, they could be a soporific. The frontier itself was finite. But what about the next frontier? And the next? And the next? Huth could be right, in this at least: Perhaps parapsychology had been too long exploring the unknown of its present frontier. Some must remain behind to develop and consolidate. But others must keep moving on! To look forever beyond the next horizon! There was the challenge. There was the dream forever bright. Lucifer thought of his crude experiment with the psi positive children, and he admitted now what he had denied at the time: Not for a decade had he been so excited by any experiment; it had brought back the wonder of the moment when an aimless undergraduate had first come upon the Rhine card tests. Lord, that was more than twenty years ago! For twenty years he had been walking in Rhine's shadow. And his personal, private dreams had never lived to see sunlight. When would science learn to use genius without being smothered by it? Freud and Einstein had left a vision to their sciences, not a citadel. They had tried to cast a light, not a shadow. Rhine had brought psi into his laboratory to demonstrate its scientific validity. Now, the physicist, the biochemist, the mathematician and, yes, the geneticist--all of them, must take this validity into their own laboratories. The parapsychologist must become the physical scientist; the physical scientist must become the parapsychologist. Only from the total crucible of science could psi emerge in a useful form. But what of Huth, and Mendel's Planet? However it had been brought together, whatever one thought of it, this living laboratory was now a fact. Psi was being mated to psi; children were being born, children with a psi potential that could be trained into a power of unknown magnitude. Huth had described it well: A laboratory on the scale of life itself! Huth knew his semantics, all right. The barbs of his words got under the skin, hooked and held fast. How pallid an Earth laboratory would seem after Mendel's Planet. The symbol cards seemed to have lost their meaning. A dozen projects clamored to reach the surface of Lucifer's thinking. Each cried out its siren challenge; each demanded experimentation. How much there was to do here on Mendel's Planet! Now, Nina was at his side, and she said gently, "It's raining again, Lucifer. Won't you come in?" The rain had returned, and the big, splashing drops hadn't fallen into his thoughts. But they were coursing in streams down his cheeks, dripping from his eyebrows. He brushed them away, and stared at the forest. The shadows had merged. The flowering beauty was like a mirage that had never been, and never could be. There was only the wash of the rain on the forest roof, the drip-drop-drip on the molding carpet of dead leaves. * * * * * Albert Fetzer came back that night. The click in the visagraph, the deeper blackness of the walls, the silent opening of the casement window--these were the now recognizable signs of his coming. Lucifer hadn't been able to sleep. Nina had already gone to bed, after pressing her lips to his cheek in a swift gesture that left him more unsettled than ever. When he realized that Fetzer was coming, Lucifer sat up on the couch and drew the sheet around his shoulders. In a moment the stocky figure squeezed through the window. "Hi, there," Fetzer called softly. "You awake, Dr. Brill?" "I haven't slept." "How'd things go today?" How had things gone? "I'm not sure," Lucifer evaded. "You got it all figured out?" "Well--not exactly." Lucifer was stunned at his own reluctance to discuss matters with Fetzer. Anything less than total frankness was a new facet of himself. It was one he didn't like. But how could he share his indecision? "We had an organization meeting after I left here last night," Fetzer said. "All the section leaders made it this time. We're set to pull the plug any time you say?" "Pull.... Oh, I hadn't realized.... What do you think you can do?" "Plenty. We've learned to short-circuit the force fields in a hurry, and we can spring over a thousand men inside of two minutes. Within five minutes more, we'd be able to hit Center and the landing field." Lucifer felt himself withdrawing even more. He could see the whole psi project swept away in turmoil. Then he thought of Huth's men, so towering in their stature, so well organized, so completely equipped by a fantastically advanced technology. The revolt would be brutally crushed. "You can't do it!" he told Fetzer. "Huh?" The stocky figure tensed. "Spell it out, Doc." "You wouldn't have a chance!" "We've got a few tricks. There's a lot of vets in this bunch." "It would be suicide." Fetzer hunched closer to the couch. "Maybe it would, maybe it wouldn't. But a man can't always stop to think of things like that. You do what you got to do." The words triggered a release, and Lucifer started to talk. With an eloquence that would have astounded his graduate students at Western University, Lucifer drew a word picture of the psi project and the theory behind it. As he talked, Nina came in quietly and sat on the couch beside him, drawing up her knees inside her short gown. Lucifer spoke of their own experiments with the babies, and of the sweep of five million years of evolution foreshortened through understanding and application of Hardy's Law. Only when he came to the radiation and chemical phases of the psi project, to the pitiable _Goolies_, did his flow of words falter. He tried to pick up quickly with analysis of what training would do for their own children. But the nagging awareness of this second dishonesty, the knowledge that Nina knew what he had done and was watching him in the darkness, broke the flow of thought and his explanation trailed off into awkward silence. Albert Fetzer didn't say anything. He squatted on his heels, a humped blur in the darkness of the room. Lucifer could feel the probe of his eyes and darting mind. "So that's it," Fetzer said at last. "We guessed some of it, but we couldn't fill in the missing pieces. You learned a lot, Doc." "There's so much I haven't yet learned." "You learned enough." "Enough for what?" "We're going to pull that plug, remember?" "No!" Lucifer stood up in his agitation. "There must be another way--a better way." "You name it." "Well--naturally I'd have to think more about it. Everything here is so new to me." Fetzer stepped closer to him. His shadow was shorter even than Lucifer's, but it bulked with unseen strength. "Anything else, Doc?" "I don't understand." "You've gone for this stuff, haven't you." Lucifer recoiled from the bluntness of the question. "I am a scientist," he replied. "Or at least I have always assumed that. These ideas are as strange to me as they are to you, but I'm trying to understand and evaluate them. Isn't that important?" "Not to me it isn't--not right now. I think the other boys will feel the same." "You don't care what all this may mean?" "Nope. Not yet, anyway. I'm not a scientist, Dr. Brill. Maybe I'm not even a very smart guy and maybe I'm just as glad of it, because my feet are on the ground and I know where I want them to go. Sure, this psi stuff could be big, mighty big. Our kids could go a long way with it. I can see that. But I'm a man, not a guinea pig. I happen to go for the woman they teamed me up with, and she feels the same way about me. That's true of most of the folks here. But we're not breeding kids for someone else. We'd rather run our own show. Guess you professors have been away from ordinary people too long to realize that. You should listen to some of our boys who fought with the underground in the last war. Makes you feel kind of good about people." "Don't you realize that Huth can destroy all of you?" "I'm not the hero type, Dr. Brill. In the war, I always kept my head down and squeezed as deep in the mud as I could. But there's some things you have to do, no matter how cold your stomach feels about it." "When do you plan to do this?" From the forest came a wild, plaintive cry. Fetzer took a quick step toward the window, then paused. "You better come with me--both of you." Lucifer drew back. "Where? Why?" "I don't like to do this, Doc. But I don't like the way you sound, either. We can't take any chances." "You don't think ..." "I don't know. I'm sorry, but I don't know enough about your kind. Hurry up, now." Lucifer still held back, but Nina stood up and moved wordlessly toward the window. Fetzer's voice toughened. "Make it easy on yourself, Doc. You're coming along, one way or the other." His legs shaking, Lucifer followed Nina through the window. * * * * * The warp in the force field was at the far corner of the enclosure. At a command from Fetzer, they dropped to their knees and crawled through. A voice whispered a challenge. Fetzer answered, and they proceeded, single file, deeper into the forest. The leader guided them with a pinpoint of light escaping from his cupped hand. They followed a winding course around the root structures of the trees. Lucifer tripped once and fell sprawling into the wet, leathery leaves. As he got up, the spider loop of a vine caught him around the throat and flipped him again. "Pick up your feet and keep your head down," Fetzer warned impatiently. Their direction took them to a shallow stream, and they splashed up the middle of it for a hundred yards. The cacophony of night sounds retreated before them, closed in behind them. The rooftop of intermeshed branches and leaves dripped endlessly. Some alien creature followed them through the branches, yapping in a strident monotone. They emerged from the stream to crawl into a semi-cave formed by the enjoining roots of two great trees. Vegetation had webbed over the roots until even the dropping of water was cut off. The light of a guttering torch showed several men waiting for them. A few carried strange weapons stolen from Huth's men. Others were armed with vicious looking clubs, and long, needle-pointed stakes. It's fantastic, thought Lucifer. Cavemen prepared to challenge a mechanized force. Cavemen forty light years from home. When they saw Nina, the men stood up, surprised, uneasy. Fetzer went into some detail on what Lucifer had told him. One of the men swore, and smashed the head of his club on the sodden floor of the cave. A balding man seated Nina on a hummock in one corner of the cave. Ignoring Lucifer, they plunged into discussion of their plans. None could see any reason for further delay. The supply ship had been gone for some time, and might return soon. Its crew would add strength to Huth's base force, which numbered around eight hundred, including nurses, doctors and various technical personnel. To Lucifer, the plan sounded bold. Pathetically bold. A sizeable group would break out of their quarters and flee into the forest, drawing a portion of Huth's men in pursuit. Another group would attack Center, making it appear that this was the chief point of concentration. After delaying as long as possible, the main force would hit the landing field and try to capture the auxiliary spaceship. The men knew they couldn't handle the ship, but their work around the field had taught them enough about it to know that its armament could give them control of the base. As Lucifer listened, a sense of familiarity kept tugging at him. It was a strange sensation that he had been through something like this before. But that was ridiculous. He'd never been any closer to military action than rejection by his draftboard, which had stupidly considered parapsychology non-essential. The feeling persisted, and suddenly he identified it: Hempstead House, New London, Conn. The stories he had been told in childhood about the underground railroad and the abolitionist meetings held by the few who believed men should be free and were willing to do something about it! The memory came to him across thirty-five years of his life, and half the span of the galaxy. It came with an impact that snapped something inside him, to bring the entity, the changing personality that was himself, into focus again. But it wasn't the same focus as before. It would never be. Yet he felt more a whole person than ever before, and within him there was a surging current that could not be held back. Hempstead House had been a verity that could not be fitted into any neat cubicle of orthodoxy. New England ministers and spinsters, businessmen and farmers--all of them motivated by a life force that couldn't be duplicated in any laboratory. The same life force was in this tree cave tonight, far away from Earth. It would go with men forever, through all space and time. It would go with Lucifer Brill, too--to the end of this experience, to whatever new frontiers of science he might live to reach. It would prevent the vision from becoming the still-life picture, the theory from crystalizing into dogma. As long as the force lived in any man, it had the potential of leading all men to freedom. Psi was an unknown part of that life force. It could not always remain in the laboratory. It must bring freedom from blindness, freedom from the cubicles that restricted each man, each science. It was a weapon ... A weapon! Good Lord, why not? Lucifer stepped into the center of the group before he knew what he was going to say. But the words came: "Wait ... there may be a better way--if you have the courage to try it!" Fetzer eyed him sceptically. "We don't have much time, Doc." "Then you must make time! It's your only chance--our only chance!" The men were silent, uncertain. "Go ahead," Fetzer said. "But make it fast." "Would you fight with a knife if you had a machine gun? Would you attack on horseback if you had a jet loaded with atom bombs?" "Keep talking," said Fetzer. "The answer is obvious. You would use the best weapon available. Yet here you sit with clubs and wooden spears, ignoring a weapon so potentially powerful that it makes our H-Bomb, or some undoubtedly greater weapon of Huth's, seem like an old crossbow!" He had their attention now. He felt the force of concentration on his words. He sensed the awareness in Nina, though her eyes were hidden in the shadows beyond the wavering circle of torchlight. "Think of what I learned from Huth--what Albert Fetzer has told you. Every person was brought here because they were psi positives, because they possessed some individual psi talent. Some of you have been ashamed of that talent. Perhaps you tried to hide it back on Earth--because it made you different from other people. But you know something about it. You may have learned more about it--even experimented with it--during your months and years on this planet. You may know what even limited talents have done in perception, clairvoyance and the moving of objects through telekinesis. "These things were done by individual people, operating, as we might say, on single generators. "But now for the first time in history we have more than three thousand psi talents grouped together in one small area. "What if all the psi power here could be focused on one objective? All the men and women of Mendel's Planet--all the children--especially the children! ... focusing their combined power! "Wouldn't that give us the force of three thousand generators--fused into one unit? Instead of moving a chair across the room, making a table jump, levitating a person--why couldn't a building be moved? A spaceship crushed? An attacking force cut down like grass under an invisible mower? "Gentlemen, is there any limit to the power of a psi focus? "If a psi focus is possible, we have our own world to win--the frontiers of infinity to explore.... "Are you willing to try?" * * * * * The silence within the tree-cave lasted for an eternity. Even the breathing of the men was hushed as each struggled with this new concept. His emotional fire spent in the greatest effort of his life, Lucifer stood limp and awkward in the center of the circle, looking around at the set faces. Their eyes were fixed on the humus beneath their crossed legs. Faintly, high above the tree-cave, the wind moaned over the forest canopy, and a new wash of rain approached. It was a cold sound, though the night was steaming hot. There was a stir in the shadows, and Nina stepped between two men to join him in the circle. Her fists were clenched. "What's the matter," she cried, "don't you have faith in yourselves? Are you afraid to fight with a new weapon?" The faces turned up toward her. "Look at that torch!" she commanded. "Now, put it out! All of us together put it out!" She turned toward the torch, which had been thrust into a fibrous root structure. She half-closed her eyes. Her lips stretched taut; her fingers knotted and unknotted in an agony of concentration. The flame flickered violently in the still air of the cave, but it did not go out. "You're not helping me!" Nina cried: "I'm not strong enough alone--none of us are! Please!" Abruptly, the torch twisted in its base, the wood snapped with the crack of a rifle shot. The tree-cave was dark. Nina's voice was spent, triumphant. "See! Now do you have faith in yourselves? Didn't you feel what Dr. Brill meant by a psi focus? Think of what it will be like to be in a focus of three thousand minds! Are you still afraid?" A man groped his way to the broken remnant of the torch. He re-lit the upper portion. "I'm thinking of my own kid," he said. "I've seen what he can do all by himself." Fetzer spoke up. "I've tried it myself. I can't do it always, but sometimes it happens. I don't know why, but it happens." One after another the men spoke out, digging into hidden memories for some personal or observed experience. "My wife was a kick," recalled a scrawny little man with a huge nose. "Not the woman I got me now, but the one I had back in Portland. She never would read no cards, but when she got mad, all hell would bust loose! Once we both got mad the same time, and you never saw so much stuff zinging around! The neighbors called the cops." They fell silent again, thinking. Nina slipped her hand into Lucifer's. It was icy cold. "You'd better sit down," he told her. She shook her head. Then Fetzer spoke up. "How could we try this thing, Doc?" It was the question Lucifer had been hoping for, and fearing. The problems ahead were piling up. He was a teacher, a scientist, not a leader. But he couldn't let his doubts show now. "We can test it tomorrow night--if you can get word to all the people by that time." "We can." Once committed, the men plunged quickly into new plans. The guard tower on the hill behind the compound was picked for the first target. Almost everyone could see it from their own quarters. And it was large enough to provide a valid test for Lucifer's psi focus theory. The searchlight that always blazed on with the coming of dusk would be the signal. "If it works," said Fetzer, "we've got to be ready to go all the way. They might not know what happened exactly, but you can be sure they'll move in and clamp down fast." It was decided that a modified version of the original attack plan would be followed if the experiment succeeded. Only this time the diversionary forces would hit the Center and the small spaceport, while the main effort would be concentrated on getting the rest of the people into a clearing just outside the compound. From there they would try to function as a psi unit. The wail of a forest animal drifted through the night. "The boys are getting ready to short the field again," Fetzer explained. "We'd better get back." He held out his hand to Lucifer. "Sorry, Doc." They made good time back to the compound, and the group split up as they approached it. Fetzer took Nina and Lucifer to their quarters and showed them how to locate the warp. "So long," he said. "Good luck to us all." Nina and Lucifer ducked through the warp, but did not go immediately inside. They watched the clouds shred apart, and the incredibly brilliant stars light up the night. "I wonder where Earth is?" Nina whispered. "We couldn't see it if we knew." "Do you think we'll ever get back, Lucifer?" "I don't know." She slipped her arm through his. "Maybe I shouldn't say this, but I have a feeling that we won't. That we will never see our own sun rise again." He was silent, feeling the weight of her words, the unknown to come, the burden of his responsibility. "It was hard for me to say that," she continued quietly. "I loved Earth. I loved its beauty and its ugliness. I loved its poor blind people. I loved them all, for I was part of them, and my eyes belonged to them. I could never hate anyone." She put her cheek against his, and her breath was warmer than the warmth of the night. Lucifer did not draw away. He asked, "Do you have a sense of what may happen tomorrow?" "Only a sense of much pain. Beyond that, I can't see. It may be just as well. Are you afraid, Lucifer?" "A little." "It is good to be a little afraid, always." "What about you--are you ever afraid, Nina?" It was the first time he had spoken the name of this strange woman who bore his child. "I am afraid, but I am at peace, too. If we do not come through this, there will be nothing more to the end of time. But if we do, we will have a child who can see, and its life will belong to us. Isn't that a wonderful thought?" Lucifer trembled under the added burden, but he thrust it from his mind, lest she perceive it there. Time enough for her to know the truth when they knew the future. "We'd better go in," he said. Her cheek turned. Her mouth found his. * * * * * When Huth called them shortly after breakfast, Lucifer was already at work in front of the visagraph screen. He held up a sheet of scribbling, and forced himself to speak with animation. "Here are some further possibilities based on our findings of yesterday. Can we work on them here today?" Huth looked interested. "Along what lines are you proceeding, Dr. Brill?" "All the primary needs and functions of a child could be related to psi, just as well as the feeding. I am intrigued by the possibility of stimulus and response in the prenatal stage. Mrs. Brill believes she has heard or read that thumb-sucking begins within the womb. Could you verify this with Dr. Thame? If it is indeed the case, the need expressed by the foetus in sucking its thumb might be answered psionically by a perceptive mother, thus strengthening the psi sense and building reliance on it at an even earlier stage of development." "Splendid, Dr. Brill!" Lucifer pointed to the stack of books beside him on the couch. "Earlier this morning, I asked for some works on the infant brain, and several books on electroencephalography were delivered by the tubicular. In scanning them, I find several items that may be fruitful for future research. For example, electrodes attached to the belly of a pregnant woman in the eighth month of gestation record an irregular pattern of delta waves. It also appears that both delta and theta are typically infantile rhythms, and that theta activity is early associated with such non-visual stimulation as pleasure, pain and frustration. The pathways on this frontier go in many directions." "Follow them where you will!" There was deep satisfaction in Huth's voice. "May I say, Dr. Brill, that I have misjudged the potential adaptability of the Earth scientific mind, when it is given proper stimulus and motivation. Your progress has been remarkable, truly remarkable! Would you be content to return to your old cubicle?" "No," Lucifer answered steadily. "I would not." The day dragged endlessly, even with the research to occupy his attention. It might have been easier if he could have talked with Nina about what lay ahead, but he dared not risk a chance word being monitored. They could only try to talk casually about themselves and the research. As the minutes crawled by, new doubts tormented him. Would Fetzer and his men be able to contact everyone? Would the people believe enough in their own power to make a serious attempt at focusing it on the guard tower? If the test failed, he had no doubts that the men would go ahead with their original plan. Nina smiled whenever their eyes met, but for all its strength her dark face showed the strain of waiting. Near the end of the day, she sat beside him, brushed her lips against the edge of his mustache, and let them creep up to his ear. "I love you," she whispered. "I want to say it now, and then think only of what we must try to do." Rain came with the first of dusk. It had been holding back since mid-day, building up rolling black thunderheads. Now it came with such fury that it blotted out the view of the compound and the guard tower. Nina looked stricken. "The signal!" she whispered. "What will we do?" Lucifer could only stare through the rain-washed window and repeat to himself the fragment of a prayer he had learned from his father. With deepening of dusk, the rain lifted a little, but they still couldn't know whether the light would be visible. A sudden gust could blot it out. Huth called on the visagraph. "I will send a car for you," he said. "I thought it might be pleasant to dine together and pass this miserable evening in stimulating conversation!" "Thank you," said Lucifer. He hoped his concern didn't show. From the corner of his eye he could see Nina by the window, straining to catch the first glimpse of the signal light. He must delay Huth in sending for them! Lucifer picked up a book. "I will bring this along," he said. "This afternoon I encountered another concept that may help...." As he had hoped, Huth could not resist the bait. "That's most interesting, Dr. Brill." "It has to do with what might be called the relationship between the anatomical maturing of the brain and the changing of rhythm patterns as the child grows older. This has not been applied to psi patterns--" "By all means, let's discuss it, Dr. Brill! Now--" "Another factor," Lucifer continued desperately, "may be the alpha rhythm patterns in a child. While these emerge very infrequently below the age of three, and do not appear with regularity until around the age of eleven, there is evidence to indicate that alpha rhythm characteristics are hereditary, and that...." As Lucifer talked, he saw that Nina's body had become rigid, that her fingers were extended and shaking, with the frenzy of a drowning person trying to reach something just beyond his grasp. "... and that environmental factors may affect the frequency of alpha rhythms during the period of childhood. For example, two uniovular twins--" A cry of pain escaped from Nina's lips. Huth showed he had heard it. "Is something wrong, Dr. Brill?" "Mrs. Brill may have fallen--I will--" And then it came, more a rending than an explosion. It was like a gigantic steel beam snapping apart from an irresistible pressure within its molecules. Their dwelling and the ground beneath it shuddered. Nina cried out again, a cry in which agony and triumph were one. Huth leaped back from the screen. A terrible rage was stamped on his bronze features. "Dr. Brill, if you are responsible for whatever has happened...." The screen went dark. Lucifer rushed to the window, tore Nina away from it. He caught a glimpse of white flames in the darkness. "Hurry! Through the warp!" he shouted. She followed woodenly, in a state of psychic shock. Her head struck the edge of the warp. Lucifer had to make her bend in order to get through. The drenching rain revived her a little. "Oh, Lucifer.... It hurt me so.... I tried so hard...." She was sobbing, and her tears became part of the rain on her cheeks. "It was like trying to swim against the tide of all the oceans in the universe. And the tide was pushing me back--and then, all of a sudden, the tide was with me--and I was tumbled and choked--in breakers as high as the stars." She pressed hard against him, her strong body contorting in a spasm that was more than muscular. Words tore themselves from lips that quivered and twisted: "Dear God! We've never lived before! A new world, and we're not strong enough to live there, Lucifer--Not strong enough yet! I can't go back to it--but I want to--I want to so much." * * * * * They skirted the compound, just within the fringe of the forest. As they ran, other shadow forms joined them in the scramble toward the meeting place. Children, awed momentarily to silence, ran nimbly ahead of their parents. A baby wailed. Seachlights probed through the rain, thrusting at the forest. Blocks of light and shadow flickered between the trees. It was like a film running wild in its projector. The light in the bow of the spaceship blazed on, and the misty twilight became a phosphorescent glow, a great dome of brilliance that arched up to the churning black clouds. A shouting came from the direction of Center. The first attack group had struck. Sounds of the second attack came from the area of the spaceship. The dome of light shimmered, then steadied, with eye-aching brightness. The second diversionary group, the one led by the little man with the huge nose, was now engaged. The clearing opened ahead. It already teemed with activity. Fetzer and his sector leaders were channeling all comers into groups of about fifty, each under one of the leaders. The groups were fanned out along the edge of the clearing, facing toward the compound. Except for the muted crying of the very young, and the low-voiced commands from the sector leaders, the groups were quiet. Fetzer ran to Lucifer. "Better stay with me. This is your show from now on! Just tell me what you want us to do, and I'll pass the signal along. My God! Did you see what happened to the guard tower?" "Some of it." "Do you think we can do anything like that again?" Lucifer looked over the nearest group. Many of the adults showed the same shock he had seen in Nina. The children were no longer so awed, and their eyes were strangely bright. "I don't know what we can do again," he answered. "And I'm not sure I want to know." The clearing filled rapidly. Each sector leader's group was separated by about ten yards from the next, and all formed an uneven, convex line some four hundred yards from end to end. "All set, Doc," said Fetzer. He fired a cylindrical weapon, and a streak of orange light curved over the compound. "That's to give our boys a chance to get back into the woods--those that still can. They'll be ready to hit again--if this other thing doesn't work." He waited for orders. Lucifer stared across the compound. The fear in his stomach made him feel like retching. These people were waiting for him to lead! Incredible. "You have to go on now," Nina said. His stomach was still sick, but he managed to smile at her. Through the slackening downpour he saw the bare walls and flat roof of Center. "The Center," he told Fetzer. Word leaped from group to group. Center. Center. Children picked it up excitedly. "Now," said Lucifer. Fetzer brought his arm down sharply. Lucifer saw the people around him pull themselves together for another effort. Nina looked faint. Nothing happened. Most of the children were bouncing with excitement. They still hadn't joined the psi focus. Lucifer ran up to a freckle-faced boy of about five. "Let's have some fun," he said. "Blow up Center just like you did the guard tower!" The words rippled from child to child, spoken and unspoken. Now it was a game instead of an awesome duty. Hey, Tommy, this is going to be neat. Blow up Center! Wow! Watch me. Aw, you aren't so hot! Quit shovin', will ya'? I can't see. Center. Blow up Center! Oh, boy! Lucifer gripped the freckled boy by the shoulders. "All right," he said, "you show them all.... Now!" The boy's eyes glowed brighter. He'd show 'em. Right here in front of Mom and Dad. You bet he would! Just watch. As child after child joined the psi focus, each grew quiet. In some deep center of his being, Lucifer had the sense of a dark, rushing wind, a nightmare sense of falling into a void, and screaming, though you knew you would never reach the bottom. Once again came that rending crack. Center disintegrated. There were no flying fragments. Just disintegration. A white light that was whiter than light. The children buzzed ecstatically. Their parents were numb and silent. Lucifer knew that if Huth still lived, he must be reorganizing his concept of what had originally happened. His reasoning would soon bring him to the truth. There was a period of quiet. It strengthened in Lucifer the belief that Huth was alive and calmly directing the operation. He found himself hoping that Huth, indeed, was alive. He had a respect for the man that bordered on a sense of kinship. The quiet was broken as Huth's men fanned in small groups through the compound. They moved with great, leaping strides. One squad probed toward the clearing. When its leader realized how many Earth people were assembled there, he signalled for a quick retreat toward the spaceship. Again there was stillness. "What now, Doc?" asked Fetzer. He looked five years older. "Shall we blast that ship before it opens up on us?" Lucifer shook his head. "I don't think it will open up--not just yet. This project means too much to Huth. He'll try to save as much of it as possible." Once more groups of Huth's men scattered through the compound. This time the groups were larger. They followed converging courses that would end at the clearing. "They're rushing us!" cried Fetzer. "Stop them!" The command leaped from sector leader to sector leader. Lucifer picked up the freckled boy so that he could see across the compound. "Now we'll have some more fun," he said. "Those men are trying to get here. Let's see if you can stop them." "Betcha we can!" Stop 'em! Stop 'em! Word of the new game spread psionically from child to child, and was repeated vocally. One tiny girl bounced up and down in glee, dancing, first on one foot and then the other, as if she were skipping rope. A shrill whistle launched the attack. Five squads converged on the clearing. The bronze faces of Huth's men were impassive. Their long legs covered nearly three yards at a stride. Each man carried a short, silver-colored tube. Once again the adults were first to project themselves into psi focus. But this time the children were not so slow to join and reinforce them. The rain had stopped. The hot, humid air was motionless. And it was a motionless wind that seemed to strike Huth's men. They were swept off their feet and spun around as if caught in a tornado. The huge leader of the squad bearing down on Lucifer's sector shot backward in a rising trajectory that cleared the compound. He screamed once. A hoarse, wild scream. The freckled boy in Lucifer's arms clapped his chubby hands. Some of Huth's men smashed into dwellings and fell in broken heaps. Others landed in open spaces and rolled like tumbleweeds. The survivors crawled or ran, screaming and sobbing, toward the spaceship. "We'd better get that ship now!" Fetzer urged. "Perhaps Huth will try to talk to us first." Five minutes passed. No sign came from Huth. "They're up to something," said Fetzer. "Let's not wait anymore." The gates of one of the administration training buildings swung open, and the _Goolies_ poured out, driven and prodded by their attendants. They came straight toward the clearing, running in weird, disjointed strides or bounding along on footless stumps of legs. Monstrous heads rolled loosely, snapping from shoulder to shoulder, from chest to back. Tiny, hairless, eyeless heads were fixed and rigid. Slack mouths gaped and drooled. Lipless mouths bared perpetual smiles. Dwarfed, naked creatures bumped against the knees of eight-foot giants. It was an unbelievable synthesis of every nightmare since time began. The freckled boy wrapped his arms around Lucifer's neck. His small body shuddered. Lucifer felt his own stomach twist with the remembered horror, but he held fast to reason. The _Goolies_ were in themselves no danger. It was only their psychological effect. Huth was shrewd. He knew well the Earth framework of prejudice. If they could break up the psi focus, his own men could crash in behind them. Confirming this line of reason, Huth's men were forming again on the outskirts of the compound. "Don't let them reach the clearing!" he told Fetzer. Fetzer waved his signal. Though shaken, the adults, too, responded to reason. They tried to focus. Children pressed against their legs, sobbing. A focus seemed to form, but weakly. It was like an exhausted, distraught athlete trying to pull himself together. The _Goolies_ faltered, appeared to lose some momentum and balance. The attendants drove them forward again. They came on as though wading against a strong current. "Don't be afraid," Lucifer told the boy. "They really can't hurt you." The small body continued to tremble. "Try to stop them ... try!" "I want my Mommy...." Nina took the boy into her own arms. She cradled his face against her breasts, pressed her lips to his cheek. "Just keep your eyes closed," she cooed gently. "Everything is all right now." She stroked the wiry red hair, and murmured. "You don't have to look to stop them, do you? Why, you can stop them any time you want to! Let's tell all the other boys and girls to keep their eyes closed--and stop those people so they can't hurt Mommy and Daddy! Here, I'll help you--we'll do it together." Nina pressed her cheek tightly to the child's, and closed her eyes. The boy stopped trembling. The _Goolies_ slowed. It became harder and harder for them to move against the invisible current. An attendant picked up one of the smaller creatures and hurled it forward. In midair, the _Goolie_ rebounded and knocked the attendant off his feet. The psi current broke loose. Clusters of bodies flew in all directions, like the exploding fragments of a grenade, crashing in and through the metal walls of the compound buildings. And then all was still, except for a few broken moans. They were the loneliest sounds Lucifer had ever heard. He saw Huth, palms outstretched, walking steadily toward the clearing. "Let him come," said Lucifer. "I will talk to him." They met about thirty yards in front of the clearing. Huth's bronze features were chiseled deep with new lines. "Dr. Brill," he said, "I am shocked and disappointed. I thought you had come to believe in this great experiment." "There is no longer a question of belief--its success to this point is very obvious." "Then why do you destroy it?" "I am trying to save it." "I don't understand," said Huth. But there was hope in his eyes. "You have learned much about Earth and its people, but there is one thing you failed to learn: Man may be blind, warped and prejudiced, but his frameworks can be changed, and he must--above all--he must control his own destiny. This law has been proved so often through our history that I am surprised you missed it." Huth bowed his head to acknowledge the rebuke. "Then what do you see in the future of this project?" "I see great problems, almost insurmountable obstacles; and the threshold of a vast unknown. I see our people slowly approaching that threshold--to find their own future." Huth looked silently over the compound, over the shell of the project to which he had dedicated his life, and not even his tremendous will could keep his shoulders from sagging. "I cannot say that I truly disagree with you, Dr. Brill. But my own culture views this project from its own framework. I, too, had to fight with prejudice to keep it going. We are a mighty race, in control of a great section of the galaxy, and I doubt that you could hold out against our full power, as you have done tonight against a fragment of it on this isolated outpost." "There seems to be a new power on this tiny planet. A power greater than any of us can yet conceive," Lucifer answered calmly. "That may be; but there is the extreme likelihood of its total destruction before you can find out how to use it. I could not prevent this destruction if I tried--once it is known what happened here tonight. My people, too, have a destiny, and they are determined to pursue it." A great rumble, a mighty rush of air, swept them off their feet. The spaceship rose in a straight vertical line and leveled off some five hundred feet above the clearing. Its prow swung toward the Earth people. A finger of blue flame probed downward. Huth heaved himself to his feet. "No! No!" he shouted. "Oh, you fools...." The blue flame broadened at its extremity, until it resembled a long, inverted funnel. When it touched the ground, it reduced to grey ash a fifty foot area of buildings and trees. There was no burning, no odor, no smoke. Just a sifting of ashes that fell like snowflakes. Huth cried out in agony at this destruction of his dream. He ran toward the path of the flame, waving his arms. In the instant before the flame reached him, Huth stood motionless, arms outstretched, face straining upward, the great muscles of his neck standing out in rigid cords. And then his statuesque body was a sifting handful of grey ash, falling gently to the damp ground. The flame leaped forward. Lucifer got to his feet. He could think only one thought: That he must try to stand upright with as much dignity as possible. He heard Nina's voice, but couldn't make out the words. They were followed by a shrill, whistling sound. Surprisingly, the sound grew fainter, like a siren fading into the distance. Lucifer realized he had closed his eyes. He opened them and saw the spaceship streaking upward. It tumbled end over end, out of control. The blue funnel of flame whipped in wild circles, hissing against the clouds. The ship disappeared momentarily behind a cloud bank, then could be seen again, glowing with an incandescent brilliance. Suddenly it burst into a shower of sparks that flared like a dying meteor, and fell away into nothingness. In the clearing behind Lucifer, children chattered gleefully. * * * * * Lucifer stood by the window and listened in silence as Albert Fetzer made his report. The Earth people had returned to their quarters. Those whose dwellings had been destroyed or badly damaged were sheltered with friends for the night. Fifty-three of Huth's men and thirty of the women had survived. A score of _Goolies_ had come crawling and whimpering out of the forest. All were put under guard in one of the training buildings. Dr. Thame, his own shoulder smashed, was helping with the injured. A twenty-four hour guard was set up to watch for return of the supply ship, or any other that might come. "What about the children?" Lucifer asked. "Mostly asleep. Some of them got a little frisky and started knocking over things--until their mothers marched them off to bed." Lucifer shivered, and he was not cold. "You'd better get some sleep," he told Fetzer. "We'll meet with the section leaders early in the morning." When Fetzer was gone, Lucifer remained by the window. Nina came out of the bedroom to join him. Together they watched the clouds close out the stars, listened to the sweep of the rising wind and the drumbeat of the returning rain. The eternal rain. "Our world," said Nina. "Our new world." Lucifer started to answer, then could not speak. The weight of his thoughts was too great a burden to ease with words. Nina put her arm around him. "A frontier must always be like this," she said. But what a frontier! There were the physical problems of existence, with Huth's administration and most of his technology gone. There was the moment when the supply ship would return, when a great fleet of ships might come to see what had happened to the project. Yet those problems seemed like foothills to the towering peaks ahead, rising in range after range, beyond the outermost perimeter of thought. As Lucifer stared into this unknown, he felt his mental stature shrivel to microscopic size. How could he, or any combination of men, offer leadership into such a future? If the project could survive against the return of Huth's people, what would keep it from disintegrating and destroying itself? How could a psi focus be channeled and used constructively? How could a professor of parapsychology, a professor who knew less about his subject than the youngest child on this planet, assail such peaks? And the children! A freckled boy whimpering in his arms. A boy with a potential power that was as yet beyond the imagination. Lucifer thought of a tiny child behind the wheel of a great diesel truck, speeding through the crowded streets of a city. Or a child toying with the fuse of a hydrogen bomb. Raise that capacity for destruction to the nth power, and then.... God! Tonight, for the first time, the children had glimpsed how great their power could be. Tomorrow they would begin to play new games. Quickly they would realize that they were stronger than their parents and other adult authorities. How could such children be controlled, educated, guided to maturity? If there were problem adolescents on Earth, what problems lay ahead with adolescents who could hotrod among the stars? "But there are more than problems," Nina said, in a hushed voice. "A frontier means so much more!" His thoughts, so recently liberated from their cubicle, drew back with conditioned reluctance, then leaped toward those towering peaks. A free thought could surmount any pinnacle, and look beyond the problems to the grandeur of the infinite. The view was of a magnitude and beauty beyond his capacity to absorb. But small, incredibly wonderful details focused before him. Now he saw knowledge and knowing from all the universe pour into this steaming jungle planet through communication channels opened by a psi focus that could leap time and space. He saw knowledge and love and understanding transmitted outward again to fall like rain wherever there was parched earth. His mind drew back from the summit. It was enough to see, for an evanescent moment of wonder, just a fragment of what lay beyond the wild mountains. It was madness to look too long. The future receded; the present returned. "I was there with you," Nina said, breathlessly. He buried his face in the softness of her hair and the warm curve of her throat and shoulder. He told her about himself, and their child. She was silent and still for a long time. "I must have known," she said. "I must have known all the time, without admitting it to myself." "I'm sorry, Nina." Her strong arm tightened around him. Her answer was steady: "We must have hope, because there is so much to learn. But if our child cannot see...." Her voice shook a little, then went on firmly, "... If our child cannot see, we must find a Braille for the psi-blind! And we will walk together ... as long as we can ... on our frontier ... of infinity." 
60614	----	RAT IN THE SKULL BY ROG PHILLIPS _Some people will be shocked by this story. Others will be deeply moved. Everyone who reads it will be talking about it. Read the first four pages: then put it down if you can._ [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, December 1958. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] Dr. Joseph MacNare was not the sort of person one would expect him to be in the light of what happened. Indeed, it is safe to say that until the summer of 1955 he was more "normal", better adjusted, than the average college professor. And we have every reason to believe that he remained so, in spite of having stepped out of his chosen field. At the age of thirty-four, he had to his credit a college textbook on advanced calculus, an introductory physics, and seventy-two papers that had appeared in various journals, copies of which were in neat order in a special section of the bookcase in his office at the university, and duplicate copies of which were in equally neat order in his office at home. None of these were in the field of psychology, the field in which he was shortly to become famous--or infamous. But anyone who studies the published writings of Dr. MacNare must inevitably conclude that he was a competent, responsible scientist, and a firm believer in institutional research, research by teams, rather than in private research and go-it-alone secrecy, the course he eventually followed. In fact, there is every reason to believe he followed this course with the greatest of reluctance, aware of its pitfalls, and that he took every precaution that was humanly possible. Certainly, on that day in late August, 1955, at the little cabin on the Russian River, a hundred miles upstate from the university, when Dr. MacNare completed his paper on _An Experimental Approach to the Psychological Phenomena of Verification_, he had no slightest thought of "going it alone." It was mid-afternoon. His wife, Alice, was dozing on the small dock that stretched out into the water, her slim figure tanned a smooth brown that was just a shade lighter than her hair. Their eight-year-old son, Paul, was fifty yards upstream playing with some other boys, their shouts the only sound except for the whisper of rushing water and the sound of wind in the trees. Dr. MacNare, in swim trunks, his lean muscular body hardly tanned at all, emerged from the cabin and came out on the dock. "Wake up, Alice," he said, nudging her with his foot. "You have a husband again." "Well, it's about time," Alice said, turning over on her back and looking up at him, smiling in answer to his happy grin. He stepped over her and went out on the diving board, leaping up and down on it, higher and higher each time, in smooth coördination, then went into a one and a half gainer, his body cutting into the water with a minimum of splash. His head broke the surface. He looked up at his wife, and laughed in the sheer pleasure of being alive. A few swift strokes brought him to the foot of the ladder. He climbed, dripping water, to the dock, then sat down by his wife. "Yep, it's done," he said. "How many days of our vacation left? Two? That's time enough for me to get a little tan. Might as well make the most of it. I'm going to be working harder this winter than I ever did in my life." "But I thought you said your paper was done!" "It is. But that's only the beginning. Instead of sending it in for publication, I'm going to submit it to the directors, with a request for facilities and personnel to conduct a line of research based on pages twenty-seven to thirty-two of the paper." "And you think they'll grant your request?" "There's no question about it," Dr. MacNare said, smiling confidently. "It's the most important line of research ever opened up to experimental psychology. They'll be forced to grant my request. It will put the university on the map!" Alice laughed, and sat up and kissed him. "Maybe they won't agree with you," she said. "Is it all right for me to read the paper?" "I wish you would," he said. "Where's that son of mine? Upstream?" He leaped to his feet and went to the diving board again. "Better walk along the bank, Joe. The stream is too swift." "Nonsense!" Dr. MacNare said. He made a long shallow dive, then began swimming in a powerful crawl that took him upstream slowly. Alice stood on the dock watching him until he was lost to sight around the bend, then went into the cabin. The completed paper lay beside the typewriter. * * * * * Alice had her doubts. "I'm not so sure the board will approve of this," she said. Dr. MacNare, somewhat exasperated, said, "What makes you think that? Pavlov experimented with his dog, physiological experiments with rats, rabbits, and other animals go on all the time. There's nothing cruel about it." "Just the same...." Alice said. So Dr. MacNare cautiously resisted the impulse to talk about his paper with his fellow professors and his most intelligent students. Instead, he merely turned his paper in to the board at the earliest opportunity and kept silent, waiting for their decision. He hadn't long to wait. On the last Friday of September he received a note requesting his presence in the board room at three o'clock on Monday. He rushed home after his last class and told Alice about it. "Let's hope their decision is favorable," she said. "It has to be," Dr. MacNare answered with conviction. He spent the week-end making plans. "They'll probably assign me a machinist and a couple of electronics experts from the hill," he told Alice. "I can use graduate students for work with the animals. I hope they give me Dr. Munitz from Psych as a consultant, because I like him much better than Veerhof. By early spring we should have things rolling." Monday at three o'clock on the dot, Dr. MacNare knocked on the door of the board room, and entered. He was not unfamiliar with it, nor with the faces around the massive walnut conference table. Always before he had known what to expect--a brief commendation for the revisions in his textbook on calculus for its fifth printing, a nice speech from the president about his good work as a prelude to a salary raise--quiet, expected things. Nothing unanticipated had ever happened here. Now, as he entered, he sensed a difference. All eyes were fixed on him, but not with admiration or friendliness. They were fixed more in the manner of a restaurateur watching the approach of a cockroach along the surface of the counter. Suddenly the room seemed hot and stuffy. The confidence in Dr. MacNare's expression evaporated. He glanced back toward the door as though wishing to escape. "So it's _you_!" the president said, setting the tone of what followed. "This is _yours_?" the president added, picking up the neatly typed manuscript, glancing at it, and dropping it back on the table as though it were something unclean. Dr. MacNare nodded, and cleared his throat nervously to say yes, but didn't get the chance. "We--all of us--are amazed and shocked," the president said. "Of course, we understand that psychology is not your field, and you probably were thinking only from the mathematical viewpoint. We are agreed on that. What you propose, though...." He shook his head slowly. "It's not only out of the question, but I'm afraid I'm going to have to request that you forget the whole thing--put this paper where no one can see it, preferably destroy it. I'm sorry, Dr. MacNare, but the university simply cannot afford to be associated with such a thing even remotely. I'll put it bluntly because I feel strongly about it, as do the other members of the Board. _If this paper is published or in any way comes to light, we will be forced to request your resignation from the faculty._" "But why?" Dr. MacNare asked in complete bewilderment. "Why?" another board member exploded, slapping the table. "It's the most inhuman thing I ever heard of, strapping a newborn animal onto some kind of frame and tying its legs to control levers, with the intention of never letting it free. The most fiendish and inhuman torture imaginable! If you didn't have such an outstanding record I would be for demanding your resignation at once." "But that's not true!" Dr. MacNare said. "It's not torture! Not in any way! Didn't you read the paper? Didn't you understand that--" "I read it," the man said. "We all read it. Every word." "Then you should have understood--" Dr. MacNare said. "We read it," the man repeated, "and we discussed some aspects of it with Dr. Veerhof without bringing your paper into it, nor your name." "Oh," Dr. MacNare said. "Veerhof...." "He says experiments, very careful experiments, have already been conducted along the lines of getting an animal to understand a symbol system and it can't be done. The nerve paths aren't there. Your line of research, besides being inhumanly cruel, would accomplish nothing." "Oh," Dr. MacNare said, his eyes flashing. "So you know all about the results of an experiment in an untried field without performing the experiments!" "According to Dr. Veerhof that field is not untried but rather well explored," the board member said. "Giving an animal the means to make vocal sounds would not enable it to form a symbol system." "I disagree," Dr. MacNare said, seething. "My studies indicate clearly--" "I think," the president said with a firmness that demanded the floor, "our position has been made very clear, Dr. MacNare. The matter is now closed. Permanently. I hope you will have the good sense, if I may use such a strong term, to forget the whole thing. For the good of your career and your very nice wife and son. That is all." He held the manuscript toward Dr. MacNare. * * * * * "I can't understand their attitude!" Dr. MacNare said to Alice when he told her about it. "Possibly I can understand it a little better than you, Joe," Alice said thoughtfully. "I had a little of what I think they feel, when I first read your paper. A--a prejudice against the idea of it, is as closely as I can describe it. Like it would be violating the order of nature, giving an animal a soul, in a way." "Then you feel as they do?" Dr. MacNare said. "I didn't say that, Joe." Alice put her arms around her husband and kissed him fiercely. "Maybe I feel just the opposite, that if there is some way to give an animal a soul, we should do it." Dr. MacNare chuckled. "It wouldn't be quite that cosmic. An animal can't be given something it doesn't have already. All that can be done is to give it the means to fully capitalize on what it has. Animals--man included--can only do by observing the results. When you move a finger, what you really do is send a neural impulse out from the brain along one particular nerve or one particular set of nerves, but you can never learn that, nor just what it is you do. All that you can know is that when you do a definite _something_ your eyes and sense of touch bring you the information that your finger moved. But if that finger were attached to a voice element that made the sound _ah_, and you could never see your finger, all you could ever know is that when you did that particular _something_ you made a certain vocal sound. Changing the resultant effect of mental commands to include things normally impossible to you may expand the potential of your mind, but it won't give you a soul if you don't have one to begin with." "You're using Veerhof's arguments on me," Alice said. "And I think we're arguing from separate definitions of a soul. I'm afraid of it, Joe. It would be a tragedy, I think, to give some animal--a rat, maybe--the soul of a poet, and then have it discover that it is only a rat." "Oh," Dr. MacNare said. "_That_ kind of soul. No, I'm not that optimistic about the results. I think we'd be lucky to get any results at all, a limited vocabulary that the animal would use meaningfully. But I do think we'd get that." "It would take a lot of time and patience." "And we'd have to keep the whole thing secret from everyone," Dr. MacNare said. "We couldn't even let Paul have an inkling of it, because he might say something to one of his playmates, and it would get back to some member of the board. How could we keep it secret from Paul?" "Paul knows he's not allowed in your study," Alice said. "We could keep everything there--and keep the door locked." "Then it's settled?" "Wasn't it, from the very beginning?" Alice put her arms around her husband and her cheek against his ear to hide her worried expression. "I love you, Joe. I'll help you in any way I can. And if we haven't enough in the savings account, there's always what Mother left me." "I hope we won't have to use any of it, sweetheart," he said. The following day Dr. MacNare was an hour and a half late coming home from the campus. He had been, he announced casually, to a pet store. "We'll have to hurry," said Alice. "Paul will be home any minute." She helped him carry the packages from the car to the study. Together they moved things around to make room for the gleaming new cages with their white rats and hamsters and guinea pigs. When it was done they stood arm in arm viewing their new possession. * * * * * To Alice MacNare, just the presence of the animals in her husband's study brought the research project into reality. As the days passed that romantic feeling became fact. "We're going to have to do together," Joe MacNare told her at the end of the first week, "what a team of a dozen specialists in separate fields should be doing. Our first job, before we can do anything else, is to study the natural movements of each species and translate them into patterns of robot directives." "Robot directives?" "I visualize it this way," Dr. MacNare said. "The animal will be strapped comfortably in a frame so that its body can't move but its legs can. Its legs will be attached to four separate, free-moving levers which make a different electrical contact for every position. Each electrical contact, or control switch, will cause the robot body to do one specific thing, such as move a leg, utter some particular sound through its voice box, or move just one finger. Can you visualize that, Alice?" Alice nodded. "Okay. Now, one leg has to be used for nothing but voice sounds. That leaves three legs for control of the movements of the robot body. In body movement there will be simultaneous movements and sequences. A simple sequence can be controlled by one leg. All movements of the robot will have to be reduced to not more than three concurrent sequences of movement of the animal's legs. Our problem, then, is to make the unlearned and the most natural movements of the legs of the animal control the robot body's movements in a functional manner." Endless hours were consumed in this initial study and mapping. Alice worked at it while her husband was at the university and Paul was at school. Dr. MacNare rushed home each day to go over what she had done and continue the work himself. He grew more and more grudging of the time his classes took. In December he finally wrote to the three technical journals that had been expecting papers from him for publication during the year that he would be too busy to do them. By January the initial phase of research was well enough along so that Dr. MacNare could begin planning the robot. For this he set up a workshop in the garage. In early February he finished what he called the "test frame." After Paul had gone to bed, Dr. MacNare brought the test frame into the study from the garage. To Alice it looked very much like the insides of a radio. She watched while he placed a husky-looking male white rat in the body harness fastened to the framework of aluminum and tied its legs to small metal rods. Nothing happened except that the rat kept trying to get free, and the small metal rods tied to its feet kept moving in pivot sockets. "Now!" Dr. MacNare said excitedly, flicking a small toggle switch on the side of the assembly. Immediately a succession of vocal sounds erupted from the speaker. They followed one another, making no sensible word. "_He's_ doing that," Dr. MacNare said triumphantly. "If we left him in that, do you think he'd eventually associate his movements with the sounds?" "It's possible. But that would be more on the order of what we do when we drive a car. To some extent a car becomes an extension of the body, but you're always aware that your hands are on the steering wheel, your foot on the gas pedal or brake. You extend your awareness consciously. You interpret a slight tremble in the steering wheel as a shimmy in the front wheels. You're oriented primarily to your body and only secondarily to the car as an extension of you." Alice closed her eyes for a moment. "Mm hm," she said. "And that's the best we could get, using a rat that knows already it's a rat." Alice stared at the struggling rat, her eyes round with comprehension, while the loudspeaker in the test frame said, "Ag-pr-ds-raf-os-dg...." Dr. MacNare shut off the sound and began freeing the rat. "By starting with a newborn animal and never letting it know what it is," he said, "we can get a complete extension of the animal into the machine, in its orientation. So complete that if you took it out of the machine after it grew up, it would have no more idea of what had happened than--than your brain if it were taken out of your head and put on a table!" "Now I'm getting that _feeling_ again, Joe," Alice said, laughing nervously. "When you said that about my brain I thought, 'Or my soul?'" Dr. MacNare put the rat back in its cage. "There might be a valid analogy there," he said slowly. "If we have a soul that survives after death, what is it like? It probably interprets its surroundings in terms of its former orientation in the body." "That's a little of what I mean," Alice said. "I can't help it, Joe. Sometimes I feel so sorry for whatever baby animal you'll eventually use, that I want to cry. I feel so sorry for it, because _we will never dare let it know what it really is_!" "That's true. Which brings up another line of research that should be the work of one expert on the team I ought to have for this. As it is, I'll turn it over to you to do while I build the robot." "What's that?" "Opiates," Dr. MacNare said. "What we want is an opiate that can be used on a small animal every few days, so that we can take it out of the robot, bathe it, and put it back again without its knowing about it. There probably is no ideal drug. We'll have to test the more promising ones." Later that night, as they lay beside each other in the silence and darkness of their bedroom, Dr. MacNare sighed deeply. "So many problems," he said. "I sometimes wonder if we can solve them all. _See_ them all...." To Alice MacNare, later, that night in early February marked the end of the first phase of research--the point where two alternative futures hung in the balance, and either could have been taken. That night she might have said, there in the darkness, "Let's drop it," and her husband might have agreed. She thought of saying it. She even opened her mouth to say it. But her husband's soft snores suddenly broke the silence of the night. The moment of return had passed. * * * * * Month followed month. To Alice it was a period of rushing from kitchen to hypodermic injections to vacuum cleaner to hypodermic injections, her key to the study in constant use. Paul, nine years old now, took to spring baseball and developed an indifference to TV, much to the relief of both his parents. In the garage workshop Dr. MacNare made parts for the robot, and kept a couple of innocent projects going which he worked on when his son Paul evinced his periodic curiosity about what was going on. Spring became summer. For six weeks Paul went to Scout camp, and during those six weeks Dr. MacNare reorganized the entire research project in line with what it would be in the fall. A decision was made to use only white rats from then on. The rest of the animals were sold to a pet store, and a system for automatically feeding, watering, and keeping the cages clean was installed in preparation for a much needed two weeks' vacation at the cabin. When the time came to go, they had to tear themselves away from their work by an effort of will--aided by the realization that they could get little done with Paul underfoot. September came all too soon. By mid-September both Dr. MacNare and his wife felt they were on the home stretch. Parts of the robot were going together and being tested, the female white rats were being bred at the rate of one a week so that when the robot was completed there would be a supply of newborn rats on hand. October came, and passed. The robot was finished, but there were minor defects in it that had to be corrected. "Adam," Dr. MacNare said one day, "will have to wear this robot all his life. It has to be just right." And with each litter of baby rats Alice said, "I wonder which one is Adam." They talked of Adam often now, speculating on what he would be like. It was almost, they decided, as though Adam were their second child. And finally, on November 2, 1956, everything was ready. Adam would be born in the next litter, due in about three days. * * * * * The amount of work that had gone into preparation for the great moment is beyond conception. Four file cabinet drawers were filled with notes. By actual measurement seventeen feet of shelf space was filled with books on the thousand and one subjects that had to be mastered. The robot itself was a masterpiece of engineering that would have done credit to the research staff of a watch manufacturer. The vernier adjustments alone, used to compensate daily for the rat's growth, had eight patentable features. And the skills that had had to be acquired! Alice, who had never before had a hypodermic syringe in her hand, could now inject a precisely measured amount of opiate into the tiny body of a baby rat with calm confidence in her skill. After such monumental preparation, the great moment itself was anticlimactic. While the mother of Adam was still preoccupied with the birth of the remainder of the brood, Adam, a pink helpless thing about the size of a little finger, was picked up and transfered to the head of the robot. His tiny feet, which he would never know existed, were fastened with gentle care to the four control rods. His tiny head was thrust into a helmet attached to a pivot-mounted optical system, ending in the lenses that served the robot for eyes. And finally a transparent plastic cover contoured to the shape of the back of a human head was fastened in place. Through it his feeble attempts at movement could be easily observed. Thus, Dr. MacNare's Adam was born into his body, and the time of the completion of his birth was one-thirty in the afternoon on the fifth day of November, 1956. In the ensuing half hour all the cages of rats were removed from the study, the floor was scrubbed, and deodorizers were sprayed, so that no slightest trace of Adam's lowly origins remained. When this was done, Dr. MacNare loaded the cages into his car and drove them to a pet store that had agreed to take them. When he returned, he joined Alice in the study, and at five minutes before four, with Alice hovering anxiously beside him, he opened the cover on Adam's chest and turned on the master switch that gave Adam complete dominion over his robot body. Adam was beautiful--and monstrous. Made of metal from the neck down, but shaped to be covered by padding and skin in human semblance. From the neck up the job was done. The face was human, masculine, handsome, much like that of a clothing store dummy except for its mobility of expression, and the incongruity of the rest of the body. The voice-control lever and contacts had been designed so that the ability to produce most sounds would have to be discovered by Adam as he gained control of his natural right front leg. Now the only sounds being uttered were _oh_, _ah_, _mm_, and _ll_, in random order. Similarly, the only movements of his arms and legs were feeble, like those of a human baby. The tremendous strength in his limbs was something he would be unable to tap fully until he had learned conscious coördination. After a while Adam became silent and without movement. Alarmed, Dr. MacNare opened the instrument panel in the abdomen. The instruments showed that Adam's pulse and respiration were normal. He had fallen asleep. Dr. MacNare and his wife stole softly from the study, and locked the door. * * * * * After a few days, with the care and feeding of Adam all that remained of the giant research project, the pace of the days shifted to that of long-range patience. "It's just like having a baby," Alice said. "You know something?" Dr. MacNare asked. "I've had to resist passing out cigars. I hate to say it, but I'm prouder of Adam than I was of Paul when he was born." "So am I, Joe," Alice said quietly. "But I'm getting a little of that scared feeling back again." "In what way?" "He watches me. Oh, I know it's natural for him to, but I do wish you had made the eyes so that his own didn't show as little dark dots in the center of the iris." "It couldn't be helped," Dr. MacNare said. "He has to be able to see, and I had to set up the system of mirrors so that the two axes of vision would be three inches apart as they are in the average human pair of eyes." "Oh, I know," said Alice. "Probably it's just something I've seized on. But when he watches me, I find myself holding my breath in fear that he can read in my expression the secret we have to keep from him, that he is a rat." "Forget it, Alice. That's outside his experience and beyond his comprehension." "I know," Alice sighed. "When he begins to show some of the signs of intelligence a baby has, I'll be able to think of him as a human being." "Sure, darling," Dr. MacNare said. "Do you think he ever will?" "That," Dr. MacNare said, "is the big question. I think he will. I think so now even more than I did at the start. Aside from eating and sleeping, he has no avenue of expression except his robot body, and _no source of reward except that of making sense--human sense_." The days passed, and became weeks, then months. During the daytime when her husband was at the university and her son was at school, Alice would spend most of her hours with Adam, forcing herself to smile at him and talk to him as she had to Paul when he was a baby. But when she watched his motions through the transparent back of his head, his leg motions remained those of attempted walking and attempted running. Then, one day when Adam was four months old, things changed--as abruptly as the turning on of a light. The unrewarding walking and running movements of Adam's little legs ceased. It was evening, and both Dr. MacNare and his wife were there. For a few seconds there was no sound or movement from the robot body. Then, quite deliberately, Adam said, "Ah." "Ah," Dr. MacNare echoed. "Mm, Mm, ah. Ma-ma." "Mm," Adam said. The silence in the study became absolute. The seconds stretched into eternities. Then-- "Mm, ah," Adam said. "Mm, ah." Alice began crying with happiness. "Mm, ah," Adam said. "Mm, ah. Ma-ma. Mamamamama." Then, as though the effort had been too much for Adam, he went to sleep. * * * * * Having achieved the impossible, Adam seemed to lose interest in it. For two days he uttered nothing more than an occasional involuntary syllable. "I would call that as much of an achievement as speech itself," Dr. MacNare said to his wife. "His right front leg has asserted its independence. If each of his other three legs can do as well, he can control the robot body." It became obvious that Adam was trying. Though the movements of his body remained non-purposive, the pauses in those movements became more and more pregnant with what was obviously mental effort. During that period there was of course room for argument and speculation about it, and even a certain amount of humor. Had Adam's right front leg, at the moment of achieving meaningful speech, suffered a nervous breakdown? What would a psychiatrist have to say about a white rat that had a nervous breakdown in its right front leg? "The worst part about it," Dr. MacNare said to his wife, "is that if he fails to make it he'll have to be killed. He can't have permanent frustration forced onto him, and, by now, returning him to his natural state would be even worse." "And he has such a stout little heart," Alice said. "Sometimes when he looks at me I'm sure he knows what is happening and he wants me to know he's trying." When they went to bed that night they were more discouraged than they had ever been. Eventually they slept. When the alarm went off, Alice slipped into her robe and went into the study first, as she always did. A moment later she was back in the bedroom, shaking her husband's shoulder. "Joe!" she whispered. "Wake up! Come into the study!" He leaped out of bed and rushed past her. She caught up with him and pulled him to a stop. "Take it easy, Joe," she said. "Don't alarm him." "Oh." Dr. MacNare relaxed. "I thought something had happened." "Something has!" They stopped in the doorway of the study. Dr. MacNare sucked in his breath sharply, but remained silent. Adam seemed oblivious of their presence. He was too interested in something else. He was interested in his hands. He was holding his hands up where he could see them, and he was moving them independently, clenching and unclenching the metal fingers with slow deliberation. Suddenly the movement stopped. He had become aware of them. Then, impossibly, unbelievably, he spoke. "Ma ma," Adam said. Then, "Pa pa." "Adam!" Alice sobbed, rushing across the study to him and sinking down beside him. Her arms went around his metal body. "Oh, Adam," she cried happily. * * * * * It was the beginning. The date of that beginning is not known. Alice MacNare believes it was early in May, but more probably it was in April. There was no time to keep notes. In fact, there was no longer a research project nor any thought of one. Instead, there was Adam, the person. At least, to Alice he became that, completely. Perhaps, also, to Dr. MacNare. Dr. MacNare quite often stood behind Adam where he could watch the rat body through the transparent skull case while Alice engaged Adam's attention. Alice did the same, at times, but she finally refused to do so any more. The sight of Adam the rat, his body held in a net attached to the frame, his head covered by the helmet, his four legs moving independently of one another with little semblance of walking or running motion nor even of coördination, but with swift darting motions and pauses pregnant with meaning, brought back to Alice the old feeling of vague fear, and a tremendous surge of pity for Adam that made her want to cry. Slowly, subtly, Adam's rat body became to Alice a pure brain, and his legs four nerve ganglia. A brain covered with short white fur; and when she took him out of his harness under opiate to bathe him, she bathed him as gently and carefully as any brain surgeon sponging a cortical surface. Once started, Adam's mental development progressed rapidly. Dr. MacNare began making notes again on June 2, 1957, just ten days before the end, and it is to these notes that we go for an insight into Adam's mind. On June 4th Dr. MacNare wrote, "I am of the opinion that Adam will never develop beyond the level of a moron, in the scale of human standards. He would probably make a good factory worker or chauffeur, in a year or two. But he is consciously aware of himself as Adam, he thinks in words and simple sentences with an accurate understanding of their meaning, and he is able to do new things from spoken instructions. There is no question, therefore, but that he has an integrated mind, entirely human in every respect." On June 7th Dr. MacNare wrote, "Something is developing which I hesitate to put down on paper--for a variety of reasons. Creating Adam was a scientific experiment, nothing more than that. Both the premises on which the project was based have been proven: that the principle of verification is the main factor in learned response, and that, given the proper conditions, some animals are capable of abstract symbol systems and therefore of thinking with words to form meaningful concepts. "Nothing more was contemplated in the experiment. I stress this because--Adam is becoming deeply religious--and before any mistaken conclusions are drawn from this I will explain what caused this development. It was an oversight of a type that is bound to happen in any complex project. "Alice's experimental data on the effects of opiates, and especially the data on increasing the dose to offset growing tolerance, were based on observation of the subject alone, without any knowledge of the mental aspects of increased tolerance--which would of course be impossible except with human subjects. "Unknown to us, Adam has been becoming partly conscious during his bath. Just conscious enough to be vaguely aware of certain sensations, and to remember them afterward. Few, if any, of these half remembered sensations are such that he can fit them into the pattern of his waking reality. "The one that has had the most pronounced influence on him is, to quote him, 'Feel clean inside. Feel good.' Quite obviously this sensation is caused by his bath. "With it is a distinct feeling of disembodiment, of being--and these are his own words--'outside my body'! This, of course, is an accurate realization, because to him the robot is his body, and he knows nothing of the existence of his actual, living, rat body. "In addition to these two effects, there is a third one. A feeling of walking, and sometimes of floating, of stumbling over things he can't see, of talking, of being talked to by disembodied voices. "The explanation of this is also obvious. When he is being bathed his legs are moved about. Any movement of a leg is to him either a spoken sound or a movement of some part of his robot body. Any movement of his right front leg, for example, tells his mind that he is making a sound. But, since his leg is not connected to the sound system of his robot body, his ears bring no physical verification of the sound. The mental anticipation of that verification then becomes a disembodied voice to him. "The end result of all this is that Adam is becoming convinced that there is a hidden side of things (which there is), and that it is supernatural (which it is, _in the framework of his orientation_). "What we are going to have to do is make sure he is completely unconscious before taking him out and bathing him. His mental health is far more important than exploring the interesting avenues opened up by this unforeseen development. "I do intend, however, to make one simple test, while he is fully awake, before dropping this avenue of investigation." Dr. MacNare does not state in his notes what this test was to be: but his wife says that it probably refers to the time when he pinched Adam's tail and Adam complained of a sudden, violent headache. This transference is the one well known to doctors. Unoriented pain in the human body manifests itself as a "headache," when the source of the pain is actually the stomach, or the liver, or any one of a hundred spots in the body. The last notes made by Dr. MacNare were those of June 11, 1957, and are unimportant except for the date. We return, therefore, to actual events, so far as they can be reconstructed. We have said little or nothing about Dr. MacNare's life at the university after embarking on the research project, nor of the social life of the MacNares. As conspirators, they had kept up their social life to avoid any possibility of the board getting curious about any radical change in Dr. MacNare's habits; but as time went on both Dr. MacNare and his wife became so engrossed in their project that only with the greatest reluctance did they go anywhere. The annual faculty party at Professor Long's on June 12th was something they could not evade. Not to have gone would have been almost tantamount to a resignation from the university. "Besides," Alice had said when they discussed the matter in May, "isn't it about time to do a little hinting that you have something up your sleeve?" "I don't know, Alice," Dr. MacNare had said. Then a smile quirked his lips and he said, "I wouldn't mind telling off Veerhof. I've never gotten over his deciding something was impossible without enough data to pass judgment." He frowned. "We are going to have to let the world know about Adam pretty soon, aren't we? That's something I haven't thought about. But not yet. Next fall will be time enough." * * * * * "Don't forget, Joe," Alice said at dinner. "Tonight's the party at Professor Long's." "How can I forget with you reminding me?" Dr. MacNare said, winking at his son. "And you, Paul," Alice said. "I don't want you leaving the house. You understand? You can watch TV, and I want you in bed by nine thirty." "Ah, Mom!" Paul protested. "Nine thirty?" He suppressed a grin. He had a party of his own planned. "And you can wipe the dishes for me. We have to be at Professor Long's by eight o'clock." "I'll help you," Dr. MacNare said. "No, you have to get ready. Besides don't you have to look up something for one of the faculty?" "I'd forgotten," said Dr. MacNare. "Thanks for reminding me." After dinner he went directly to the study. Adam was sitting on the floor playing with his wooden blocks. They were alphabet blocks, but he didn't know that yet. The summer project was going to be teaching him the alphabet. Already, though, he preferred placing them in straight rows rather than stacking them up. At seven o'clock Alice rapped on the door to the study. "Time to get dressed, Joe," she called. "You'll be all right while we're gone, Adam?" Dr. MacNare said. "I be all right, papa," Adam said. "I sleep." "That's good," Dr. MacNare said. "I'll turn out the light." At the door he waited until Adam had sat down in the chair he always slept on, and settled himself. Then he pushed the switch just to the right of the door and went out. "Hurry, dear," Alice called. "I'm hurrying," Dr. MacNare protested--and, for the first time, he forgot to lock the study door. The bathroom was next to the study, the wall between them soundproofed by a ceiling-high bookshelf in the study filled with thousands of books. On the other side was the master bedroom, with a closet with sliding panels that opened both on the bedroom and the bathroom. These sliding panels were partly open, so that Dr. MacNare and Alice could talk. "Did you lock the study door?" "Of course," Dr. MacNare said. "But I'll check before we leave." "How is Adam taking being alone tonight?" Alice called. "Okay," Dr. MacNare said. "Damn!" "What's the matter, Joe?" "I forgot to get razor blades." The conversation died down. Alice MacNare finished dressing. "Aren't you ready yet, Joe?" she called. "It's almost a quarter to eight." "Be right with you. I nicked myself shaving with an old blade. The bleeding's almost stopped now." Alice went into the living room. Paul had turned on the TV and was sprawled out on the rug. "You be sure and stay home, and be in bed by nine thirty, Paul," she said. "Promise?" "Ah, Mom," he protested. "Well, all right." Dr. MacNare came into the room, still working on his tie. A moment later they went out the front door. They had been gone less than five minutes when there was a knock. Paul jumped to his feet and opened the door. "Hi, Fred, Tony, Bill," he said. The boys, all nine years old, sprawled on the rug and watched television. It became eight o'clock, eight thirty, and finally five minutes to nine. The commercial began. "Where's your bathroom?" Tony asked. "In there," Paul said, pointing vaguely at the doorway to the hall. Tony got up off the floor and went into the hall. He saw several doors, all looking much alike. He picked one and opened it. It was dark inside. He felt along the wall for a light switch and found it. Light flooded the room. He stared at what he saw for perhaps ten seconds, then turned and ran down the hall to the living room. "Say, Paul!" he said. "You never said anything about having a real honest to gosh robot!" "What are you talking about?" Paul said. "In that room in there!" Tony said. "Come on. I'll show you!" The TV program forgotten, Paul, Fred, and Bill crowded after him. A moment later they stood in the doorway to the study, staring in awe at the strange figure of metal that sat motionless in a chair across the room. Adam, it seems certain, was asleep, and had not been wakened by this intrusion nor the turning on of the light. "Gee!" Paul said. "It belongs to Dad. We'd better get out of here." "Naw," Tony said with a feeling of proprietorship at having been the original discoverer. "Let's take a look. He'll never know about it." They crossed the room slowly, until they were close up to the robot figure, marveling at it, moving around it. "Say!" Bill whispered, pointing. "What's that in there? It looks like a white rat with its head stuck into that kind of helmet thing." They stared at it a moment. "Maybe it's dead. Let's see." "How you going to find out?" "See those hinges on the cover?" Tony said importantly. "Watch." With cautious skill he opened the transparent back half of the dome, and reached in, wrapping his fingers around the white rat. He was unable to get it loose, but he succeeded in pulling its head free of the helmet. At the same time Adam awoke. "Ouch!" Tony cried, jerking his hand away. "He bit me!" "He's alive all right," Bill said. "Look at him glare!" He prodded the body of the rat and pulled his hand away quickly as the rat lunged. "Gee, look at its eyes," Paul said nervously. "They're getting blood-shot." "Dirty old rat!" Tony said vindictively, jabbing at the rat with his finger and evading the snapping teeth. "Get its head back in there!" Paul said desperately. "I don't want papa to find out we were in here!" He reached in, driven by desperation, pressing the rat's head between his fingers and forcing it back into the tight fitting helmet. Immediately screaming sounds erupted from the lips of the robot. (It was determined by later examination that only when the rat's body was completely where it should be were the circuits operable.) "Let's get out of here!" Tony shouted, and dived for the door, thereby saving his life. "Yeah! Let's get out of here!" Fred shouted as the robot figure rose to its feet. Terror enabled him to escape. Bill and Paul delayed an instant too long. Metal fingers seized them. Bill's arm snapped halfway between shoulder and elbow. He screamed with pain and struggled to free himself. Paul was unable to scream. Metal fingers gripped his shoulder, with a metal thumb thrust deeply against his larynx, paralyzing his vocal cords. Fred and Tony had run into the front room. There they waited, ready to start running again. They could hear Bill's screams. They could hear a male voice jabbering nonsense, and finally repeating over and over again, "Oh my, oh my, oh my," in a tone all the more horrible because it portrayed no emotion whatever. Then there was silence. The silence lasted several minutes. Then Bill began to sniffle, rubbing his knuckles in his eyes. "I wanta go home," he whimpered. "Me too." They took each other's hand and tiptoed to the front door, watching the open doorway to the hall. When they reached the front door Tony opened it, and when it was open they ran, not stopping to close the door behind them. * * * * * There isn't much more to tell. It is known that Tony and Bill arrived at their respective homes, saying nothing of what had happened. Only later did they come forward and admit their share in the night's events. Joe and Alice MacNare arrived home from the party at Professor Long's at twelve thirty, finding the front door wide open, the lights on in the living room, and the television on. Sensing that something was wrong, Alice hurried to her son's room and discovered he wasn't there. While she was doing that, Joe shut the front door and turned off the television. Alice returned to the living room, eyes round with alarm, and said, "Paul's not in his room!" "Adam!" Joe croaked, and rushed into the hallway, with Alice following more slowly. She reached the open door of the study in time to see the robot figure pounce on Joe and fasten its metal fingers about his throat, crushing vertebrae and flesh alike. Oblivious to her own danger, she rushed to rescue her already dead husband, but the metal fingers were inflexible. Belatedly she abandoned the attempt and ran into the hallway to the phone. When the police arrived, they found her slumped against the wall in the hallway. She pointed toward the open doorway of the study, without speaking. The police rushed into the study. At once there came the sounds of shots. Dozens of them, it seemed. Later both policemen admitted that they lost their heads and fired until their guns were empty. But it was not yet the end of Adam. It would perhaps be impossible to conceive the full horror of his last hours, but we can at least make a guess. Asleep when the boys entered the study, he awakened to a world he had never before perceived except very vaguely and under the soporific veil of opiate. But it was a world vastly different even than that. There is no way of knowing what he saw--probably blurred ghostly figures, monstrous beyond the ability of his mind to grasp, for his eyes were adjusted only to the series of prisms and lenses that enabled him to see and coördinate the images brought to him through the eyes of the robot. He saw these impossible figures, he felt pain and torture that were not of the flesh as he knew it, but of the spirit; agony beyond agony administered by what he could only believe were fiends from some nether hell. And then, abruptly, as ten-year-old Paul shoved his head back into the helmet, the world he had come to believe was reality returned. It was as though he had returned to the body from some awful pit of hell, with the soul sickness still with him. Before him he saw four human-like figures of reality, but beings unlike the only two he had ever seen. Smaller, seeming to be a part of the unbelievable nightmare he had been in. Two of them fled, two were within his grasp. Perhaps he didn't know what he was doing when he killed Paul and Bill. It's doubtful if he had the ability to think at all then, only to tremble and struggle in his pitiful little rat body, with the automatic mechanisms of the robot acting from those frantic motions. But it is known that there were three hours between the deaths of the two boys and the entry of Dr. MacNare at twelve thirty, and during those three hours he would have had a chance to recover, and to think, and to partially rationalize the nightmare he had experienced in realms outside what to him was the world of reality. Adam must certainly have been calm enough, rational enough, to recognize Dr. MacNare when he entered the study at twelve thirty. Then why did Adam deliberately kill Joe by breaking his neck? Was it because, in that three hours, he had put together the evidence of his senses and come to the realization that he was not a man but a rat? It's not likely. It is much more likely that Adam came to some aberrated conclusion dictated by the superstitious feelings that had grown so strongly into his strange and unique existence, that dictated he must kill Joseph. For it would have been impossible for him to have realized that he was only a rat. You see, Joseph MacNare had taken great care that Adam never, in all his life, should see _another_ rat. * * * * * There remains only the end of Adam to relate. Physically it can be only anticlimactic. With his metal body out of commission from a dozen or so shots, two of which destroyed the robot extensions of his eyes, he remained helpless until the coroner carefully removed him. To the coroner he was just a white rat, and a strangely helpless one, unable to walk or stand as rats are supposed to. Also a strangely vicious one, with red little beads of eyes and lips drawn back from sharp teeth the same as some rabid wild animal. The coroner had no way of knowing that somewhere in that small, menacing form there was a noble but lost mentality that knew itself as Adam, and held thoughts of a strange and wonderful realm of peace and splendor beyond the grasp of the normal physical senses. The coroner could not know that the erratic motions of that small left front foot, if connected to the proper mechanisms, would have been audible as, perhaps, a prayer, a desperate plea to whatever lay in the Great Beyond to come down and rescue its humble creature. "Vicious little bastard," the coroner said nervously to the homicide men gathered around Dr. MacNare's desk. "Let me take care of it," said one of the detectives. "No," the coroner answered. "I'll do it." Quickly, so as not to be bitten, he picked Adam up by the tip of the tail and slammed him forcefully against the top of the desk. 
60664	----	PIPE DREAM BY FRITZ LEIBER _Simon Grue found a two-inch mermaid in his bathtub. It had arms, hips, a finny tail, and (here the real trouble began) a face that reminded him irresistibly of Grushenka Stulnikov-Gurevich...._ [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, February 1959. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] It wasn't until the mermaid turned up in his bathtub that Simon Grue seriously began to wonder what the Russians were doing on the roof next door. The old house next door together with its spacious tarpapered roof, which held a sort of pent-shack, a cylindrical old water tank, and several chicken-wire enclosures, had always been a focus of curiosity in this region of Greenwich Village, especially to whoever happened to be renting Simon's studio, the north window-cum-skylight of which looked down upon it--if you were exceptionally tall or if, like Simon, you stood halfway up a stepladder and peered. During the 1920's, old-timers told Simon, the house had been owned by a bootlegger, who had installed a costly pipe organ and used the water tank to store hooch. Later there had been a colony of shaven-headed Buddhist monks, who had strolled about the roof in their orange and yellow robes, meditating and eating raw vegetables. There had followed a _commedia dell' arte_ theatrical group, a fencing salon, a school of the organ (the bootlegger's organ was always one of the prime renting points of the house), an Arabian restaurant, several art schools and silvercraft shops of course, and an Existentialist coffee house. The last occupants had been two bony-cheeked Swedish blondes who sunbathed interminably and had built the chicken-wire enclosures to cage a large number of sinister smoke-colored dogs--Simon decided they were breeding werewolves, and one of his most successful abstractions, "Gray Hunger", had been painted to the inspiration of an eldritch howling. The dogs and their owners had departed abruptly one night in a closed van, without any of the dogs ever having been offered for sale or either of the girls having responded with anything more than a raised eyebrow to Simon's brave greetings of "Skoal!" The Russians had taken possession about six months ago--four brothers apparently, and one sister, who never stirred from the house but could occasionally be seen peering dreamily from a window. A white card with a boldly-inked "Stulnikov-Gurevich" had been thumbtacked to the peeling green-painted front door. Lafcadio Smits, the interior decorator, told Simon that the newcomers were clearly White Russians; he could tell it by their bushy beards. Lester Phlegius maintained that they were Red Russians passing as White, and talked alarmingly of spying, sabotage and suitcase bombs. Simon, who had the advantages of living on the spot and having been introduced to one of the brothers--Vasily--at a neighboring art gallery, came to believe that they were both Red and White and something more--solid, complete Slavs in any case, Double Dostoevsky Russians if one may be permitted the expression. They ordered vodka, caviar, and soda crackers by the case. They argued interminably (loudly in Russian, softly in English), they went on mysterious silent errands, they gloomed about on the roof, they made melancholy music with their deep harmonious voices and several large guitars. Once Simon though they even had the bootlegger's organ going, but there had been a bad storm at the time and he hadn't been sure. They were not quite as tight-lipped as the Swedish girls. Gradually a curt front-sidewalk acquaintance developed and Simon came to know their names. There was Vasily, of course, who wore thick glasses, the most scholarly-looking of the lot and certainly the most bibulous--Simon came to think of Vasily as the Vodka Breather. Occasionally he could be glimpsed holding Erlenmayer flasks, trays of culture dishes, and other pieces of biological equipment, or absentmindedly wiping off a glass slide with his beard. Then there was Ivan, the dourest of the four, though none of them save Vasily seemed very amiable. Simon's private names for Ivan were the Nihilist and the Bomber, since he sometimes lugged about with him a heavy globular leather case. With it and his beard--a square black one--he had more than once created a mild sensation in the narrow streets of the Village. Next there was Mikhail, who wore a large crucifix on a silver chain around his neck and looked like a more spiritual Rasputin. However, Simon thought of him less as the Religious than as the Whistler--for his inveterate habit of whistling into his straggly beard a strange tune that obeyed no common harmonic laws. Somehow Mikhail seemed to carry a chilly breeze around with him, a perpetual cold draught, so that Simon had to check himself in order not to clutch together his coat collar whenever he heard the approach of the eerie piping. Finally there was Lev, beardless, shorter by several inches, and certainly the most elusive of the brothers. He always moved at a scurry, frequently dipping his head, so that it was some time before Simon assured himself that he had the Stulnikov-Gurevich face. He did, unmistakably. Lev seemed to be away on trips a good deal. On his returns he was frequently accompanied by furtive but important-looking men--a different one on each occasion. There would be much bustle at such times--among other things, the shades would be drawn. Then in a few hours Lev would be off again, and his man-about-town companion too. And of course there was the indoors-keeping sister. Several times Simon had heard one of the brothers calling "Grushenka", so he assumed that was her name. She had the Stulnikov-Gurevich face too, though on her, almost incredibly, it was strangely attractive. She never ventured on the roof but she often sat in the pent-shack. As far as Simon could make out, she always wore some dark Victorian costume--at least it had a high neck, long sleeves, and puffed shoulders. Pale-faced in the greenish gloom, she would stare for hours out of the pent-shack's single window, though never in Simon's direction. Occasionally she would part and close her lips, but not exactly as if she were speaking, at least aloud--he thought of calling her the Bubble Blower. The effect was as odd as Mikhail's whistling but not as unpleasant. In fact, Simon found himself studying Grushenka for ridiculously long periods of time. His mild obsession began to irk him and one day he decided henceforth to stay away altogether from his north window and the stepladder. As a result he saw little of the alterations the Russians began to make on the roof at this point, though he did notice that they lugged up among other things a length of large-diameter transparent plastic piping. * * * * * So much for the Russians, now for the mermaid. Late one night Simon started to fill his bathtub with cold water to soak his brushes and rags--he was working with a kind of calcimine at the time, experimenting with portable murals painted on large plaster-faced wooden panels. Heavily laden, he got back to the bathroom just in time to shut off the water--and to see a tiny fish of some sort splashing around in it. He was not unduly surprised. Fish up to four or five inches in length were not unheard-of apparitions in the cold-water supply of the area, and this specimen looked as if it displaced no more than a teaspoon of water. He made a lucky grab and the next moment he was holding in his firmly clenched right hand the bottom half of a slim wriggling creature hardly two inches long--and now Simon was surprised indeed. To begin with, it was not greenish white nor any common fish color, but palely-pinkish, flesh-colored in fact. And it didn't seem so much a fish as a tadpole--at least its visible half had a slightly oversize head shaped like a bullet that has mushroomed a little, and two tiny writhing arms or appendages of some sort--and it felt as if it had rather large hips for a fish or even a tadpole. Equip a two-months human embryo with a finny tail, give it in addition a precocious feminine sexiness, and you'd get something of the same effect. But all that was nothing. The trouble was that it had a face--a tiny face, of course, and rather goggly-ghostly like a planarian's, but a face nevertheless, a human-looking face, and also (here was the real trouble) a face that bore a grotesque but striking resemblance to that of Grushenka Stulnikov-Gurevich. Simon's fingers tightened convulsively. Simultaneously the slippery creature gave a desperate wriggle. It shot into the air in a high curve and fell into the scant inch of space between the bathtub and the wall. The next half hour was hectic in a groveling sort of way. Retrieving anything from behind Simon's ancient claw-footed bathtub was a most difficult feat. There was barely space to get an arm under it and at one point the warping of the floor boards prevented even that. Besides, there was the host of dust-shrouded objects it had previously been too much trouble to tease out--an accumulation of decades. At first Simon tried to guide himself by the faint flopping noises along the hidden base of the wall, but these soon ceased. Being on your knees and your chest with an ear against the floor and an arm strainingly outstretched is probably not the best position to assume while weird trains of thought go hooting through your head, but sometimes it has to happen that way. First came a remembered piece of neighborhood lore that supported the possibility of a connection between the house next door and the tiny pink aquatic creature now suffering minute agonies behind the bathtub. No one knew what ancient and probably larceny-minded amateur plumber was responsible, but the old-timers assured Simon there was a link between the water supply of the Russians' house with its aerial cistern and that of the building containing Simon's studio and several smaller apartments; at any rate they maintained that there had been a time during the period when the bootlegger was storing hooch in the water tank that several neighborhood cold-water taps were dispensing a weak but nonetheless authoritative mixture of bourbon and branch water. So, thought Simon as he groped and strained, if the Russians were somehow responsible for this weird fishlet, there was no insuperable difficulty in understanding how it might have gotten here. But that was the least of Simon's preoccupations. He scrabbled wildly and unsuccessfully for several minutes, and then realizing he would never get anywhere in this unsystematic manner, he began to remove the accumulated debris piece by piece: dark cracked ends of soap, washrags dried out in tortured attitudes, innumerable dark-dyed cigarette stumps, several pocket magazines with bleached wrinkled pages, empty and near-empty medicine bottles and pill vials, rusty hairpins, bobby pins, safety pins, crumpled toothpaste tubes (and a couple for oil paint), a gray toothbrush, a fifty-cent piece and several pennies, the mummy of a mouse, a letter from Picasso, and last of all, from the dark corner behind the bathtub's inside claw, the limp pitiful thing he was seeking. It was even tinier than he'd thought. He carefully washed the dust and flug off it, but it was clearly dead and its resemblance to Grushenka Stulnikov-Gurevich had become problematical--indeed, Simon decided that someone seeing it now for the first time would think it a freak minnow or monstrous tadpole and nothing more, though mutation or disease had obviously been at work. The illusion of a miniature mermaid still existed in the tapering tail and armlike appendages, but it was faint. He tried to remember what he knew about salamanders--almost nothing, it turned out. He thought of embryos, but his mind veered away from the subject. He wandered back into the studio carrying the thing in his hand. He climbed the stepladder by the north window and studied the house next door. What windows he could see were dark. He got a very vague impression that the roof had changed. After he had strained his eyes for some time he fancied he could see a faint path of greenish luminescence streaming between the pent-shack and the water-tank, but it was very faint indeed and might only be his vision swimming. He climbed down the stepladder and stood for a moment weighing the tiny dead thing in his hand. It occurred to him that one of his friends at the university could dig up a zoologist to pass on his find. But Simon's curiosity was more artistic than scientific. In the end he twisted a bit of cellophane around the thing, placed it on the ledge of his easel and went off to bed ... and to a series of disturbingly erotic dreams. * * * * * Next day he got up late and, after breakfasting on black coffee, gloomed around the studio for a while, picking things up and putting them down. He glanced frequently at the stepladder, but resisted the temptation to climb up and have another look next door. Sighing, he thumbtacked a sheet of paper to a drawing board and half-heartedly began blocking in a female figure. It was insipid and lifeless. Stabbing irritably at the heavy curve of the figure's hip, he broke his charcoal. "Damn!" he said, glaring around the room. Abandoning all pretense, he threw the charcoal on the floor and climbed the stepladder. He pressed his nose against the glass. In daylight, the adjoining roof looked bare and grimy. There was a big transparent pipe running between the water tank and the shack, braced in two places by improvised-looking wooden scaffolding. Listening intently, Simon thought he could hear a motor going in the shack. The water looked sallow green. It reminded Simon of those futuristic algae farms where the stuff is supposed to be pumped through transparent pipes to expose it to sunlight. There seemed to be a transparent top on the water tank too--it was too high for Simon to see, but there was a gleam around the edge. Staring at the pipe again, Simon got the impression there were little things traveling in the water, but he couldn't make them out. Climbing down in some excitement, Simon got the twist of cellophane from the ledge of the easel and stared at its contents. Wild thoughts were tumbling through his head as he got back up on the stepladder. Sunlight flashed on the greenish water pipe between the tank and the shack, but after the first glance he had no eyes for it. Grushenka Stulnikov-Gurevich had her face tragically pressed to the window of the shack. She was wearing the black dress with high neck and puffed shoulders. At that moment she looked straight at him. She lifted her hands and seemed to speak imploringly. Then she slowly sank from sight as if, it horridly occurred to Simon, into quicksand. Simon sprang from his chair, heart beating wildly, and ran down the stairs to the street. Two or three passersby paused to study him as he alternately pounded the flaking green door of the Russians' house and leaned on the button. Also watching was the shirt-sleeved driver of a moving van, emblazoned "Stulnikov-Gurevich Enterprises," which almost filled the street in front of the house. The door opened narrowly. A man with a square black beard frowned out of it. He topped Simon by almost a head. "Yes?" Ivan the Bomber asked, in a deep, exasperated voice. "I must see the lady of the house immediately," Simon cried. "Your sister, I believe. She's in danger." He surged forward. The butt of the Bomber's right palm took him firmly in the chest and he staggered back. The Bomber said coldly, "My sister is--ha!--taking a bath." Simon cried, "In that case she's drowning!" and surged forward again, but the Bomber's hand stopped him short. "I'll call the police!" Simon shouted, flailing his limbs. The hand at his chest suddenly stopped pushing and began to pull. Gripped by the front of his shirt, Simon felt himself being drawn rapidly inside. "Let go! Help, a kidnapping!" he shouted to the inquisitive faces outside, before the door banged shut. "No police!" rumbled the Bomber, assisting Simon upstairs. "Now look here," Simon protested futilely. In the two-story-high living room to his right, the pipes of an organ gleamed golden from the shadows. At the second landing, a disheveled figure met them, glasses twinkling--Vasily the Vodka Breather. He spoke querulously in Russian to Ivan, who replied shortly, then Vasily turned and the three of them crowded up the narrow third flight to the pent-shack. This housed a small noisy machine, perhaps an aerator of some sort, for bubbles were streaming into the transparent pipe where it was connected to the machine; and under the pipe, sitting with an idiot smile on a chair of red plush and gilt, was a pale black-mustached man. An empty clear-glass bottle with a red and gold label lay on the floor at his feet. The opposite side of the room was hidden by a heavy plastic shower curtain. Grushenka Stulnikov-Gurevich was not in view. Ivan said something explosive, picking up the bottle and staring at it. "Vodka!" he went on. "I have told you not to mix the pipe and the vodka! Now see what you have done!" "To me it seemed hospitable," said Vasily with an apologetic gesture. "Besides, only one bottle--" Ducking under the pipe where it crossed the pent-shack, Ivan picked up the pale man and dumped him crosswise in the chair, with his patent-leather shoes sticking up on one side and his plump hands crossed over his chest. "Let him sleep. First we must take down all the apparatus, before the capitalistic police arrive. Now: what to do with this one?" He looked at Simon, and clenched one large and hairy fist. "_Nyet-nyet-nyet_," said the Vodka Breather, and went to whisper in Ivan's ear. They both stared at Simon, who felt uncomfortable and began to back toward the door; but Ivan ducked agilely under the pipe and grasped him by the arm, pulling him effortlessly toward the roof exit. "Just come this way if you please, Mr. Gru-_ay_," said Vasily, hurrying after. As they left the shack, he picked up a kitchen chair. Crossing the roof, Simon made a sudden effort and wrenched himself free. They caught him again at the edge of the roof, where he had run with nothing clearly in mind, but with his mouth open to yell. Suspended in the grip of the two Russians, with Ivan's meaty palm over his mouth, Simon had a momentary glimpse of the street below. A third bearded figure, Mikhail the Religious, was staring up at them from the sunny sidewalk. The melancholy face, the deep-socketed tormented eyes, and the narrow beard tangled with the dangling crucifix combined to give the effect of a Tolstoy novel's dust-jacket. As they hauled Simon away, he had the impression that a chilly breeze had sprung up and the street had darkened. In his ears was Mikhail's distant, oddly discordant whistling. Grunting, the two brothers set Simon down on the kitchen chair and slid him across the roof until something hard but resilient touched the top of his head. It was the plastic pipe, through which, peering upward, he could see myriads of tiny polliwog-shapes flitting back and forth. "Do us a kindness not to make noise," said Ivan, removing his palm. "My brother Vasily will now explain." He went away. * * * * * Curiosity as much as shock kept Simon in his chair. Vasily, bobbing his head and smiling, sat down tailor-fashion on the roof in front of him. "First I must tell you, Mr. Gru-_ay_, that I am specialist in biological sciences. Here you see results of my most successful experiment." He withdrew a round clear-glass bottle from his pocket and unscrewed the top. "Ah?" said Simon tentatively. "Indeed yes. In my researches, Mr. Gru-_ay_, I discovered a chemical which will inhibit growth at any level of embryonic development, producing a viable organism at that point. The basic effect of this chemical is always toward survival at whatever level of development--one cell, a blastula, a worm, a fish, a four-legger. This research, which Lysenko scoffed at when I told him of it, I had no trouble in keeping secret, though at the time I was working as the unhappy collaborator of the godless soviets. But perhaps I am being too technical?" "Not at all," Simon assured him. "Good," Vasily said with simple satisfaction and gulped at his bottle. "Meanwhile my brother Mikhail was a religious brother at a monastery near Mount Athos, my Nihilist brother Ivan was in central Europe, while my third brother Lev, who is of commercial talents, had preceded us to the New World, where we always felt it would some day be our destiny to join one another. "With the aid of brother Ivan, I and my sister Grushenka escaped from Russia. We picked up Mikhail from his monastery and proceeded here, where Lev had become a capitalist business magnate. "My brothers, Ivan especially, were interested in my research. He had a theory that we could eventually produce hosts of men in this way, whole armies and political parties, all Nihilist and all of them Stulnikov-Gureviches. I assured him that this was impossible, that I could not play Cadmus, for free-swimming forms are one thing, we have the way to feed them in the aqueous medium; but to make fully developed mammals placental nourishment is necessary--that I cannot provide. Yet to please him I begin with (pardon me!) the egg of my sister, that was as good a beginning as any and perhaps it intrigued my vanity. Ivan dreamed his dreams of a Nihilist Stulnikov-Gurevich humanity--it was harmless, as I told myself." Simon stared at him glassy-eyed. Something rather peculiar was beginning to happen inside his head--about an inch under the point where the cool water-filled plastic pipe pressed down on his scalp. Little ghostly images were darting--delightfully wispy little girl-things, smiling down at him impudently, then flirting away with a quick motion of their mermaid tails. The sky had been growing steadily darker and now there came the growl of thunder. Against the purple-gray clouds Simon could barely make out the semi-transparent shapes of the polliwogs in the pipe over his head; but the images inside his mind were growing clearer by the minute. "Ah, we have a storm," Vasily observed as the thunder growled again. "That reminds me of Mikhail, who is much influenced by our Finnish grandmother. He had the belief as a child that he could call up the winds by whistling for them--he even learned special wind musics from her. Later he became a Christian religious--there are great struggles in him. Mikhail objected to my researches when he heard I used the egg of my sister. He said we will produce millions of souls who are not baptized. I asked him how about the water they are in, he replied this is not the same thing, these little swimmers will wriggle in hell eternally. This worried him greatly. We tried to tell him I had not used the egg of my sister, only the egg of a fish. "But he did not believe this, because my sister changed greatly at the time. She no longer spoke. She put on my mother's bathing costume (we are a family people) and retired to the bathtub all day long. I accepted this--at least in the water she is not violent. Mikhail said, "See, her soul is now split into many unredeemed sub-souls, one each for the little swimmers. There is a sympathy between them--a hypnotic vibration. So long as you keep them near her, in that tank on the roof, this will be. If they were gone from there, far from there, the sub-souls would reunite and Grushenka's soul would be one again." He begged me to stop my research, to dump it in the sea, to scatter it away, but Lev and Ivan demand I keep on. Yet Mikhail warned me that works of evil end in the whirlwind. I am torn and undecided." He gulped at his vodka. Thunder growled louder. Simon was thinking, dreamily, that if the soul of Grushenka Stulnikov-Gurevich were split into thousands of sub-souls, vibrating hynotically in the nearby water tank, with at least one of them escaping as far as his bathtub, then it was no wonder if Grushenka had a strange attraction for him. "But that is not yet the worst," Vasily continued. "The hypnotic vibrations of the free-swimming ones in their multitude turn out to have a stimulating effect on any male who is near. Their sub-minds induce dreams of the piquant sort. Lev says that to make money for the work we must sell these dreams to rich men. I protest, but to no avail." "Lev is maddened for money. Now besides selling the dreams I find he plans to sell the creatures themselves, sell them one by one, but keep enough to sell the dreams too. It is a madness." The darkness had become that of night. The thunder continued to growl and now it seemed to Simon that it had music in it. Visions swam through his mind to its rhythm--hordes of swimming pygmy souls, of unborn water babies, migrations of miniature mermaids. The pipe hanging between water tank and pent-shack became in his imagination a giant umbilicus or a canal for a monstrous multiple birth. Sitting beneath it, helpless to move, he focused his attention with increasing pleasure on the active, supple, ever more human girl-bodies that swam across his mind. Now more mermaid than tadpole, with bright smiling lips and eyes, long Lorelei-hair trailing behind them, they darted and hovered caressingly. In their wide-cheeked oval faces, he discovered without shock, there was a transcendent resemblance to the features of Grushenka Stulnikov-Gurevich--a younger, milk-skinned maiden of the steppes, with challenging eyes and fingers that brushed against him with delightful shocks.... "So it is for me the great problem," Vasily's distant voice continued. "I see in my work only the pure research, the play of the mind. Lev sees money, Ivan sees dragon teeth--fodder for his political cannon--Mikhail sees unshriven souls, Grushenka sees--who knows?--madness. It is indeed one great problem." * * * * * Thunder came again, crashingly this time. The door of the pent-shack opened. Framed in it stood Ivan the Bomber. "Vasily!" he roared. "Do you know what that idiot is doing now?" As the thunder and his voice trailed off together, Simon became aware at last of the identity of the other sound, which had been growing in volume all the time. Simultaneously Vasily struggled to his feet. "The organ!" he cried. "Mikhail is _playing_ the Whirlwind Music! We must stop him!" Pausing only for a last pull at the bottle, he charged into the pent-shack, following Ivan. Wind was shaking the heavy pipe over Simon's head, tossing him back and forth in the chair. Looking with an effort toward the west, Simon saw the reason: a spinning black pencil of wind that was writing its way toward them in wreckage across the intervening roofs. The chair fell under him. Stumbling across the roof, he tugged futilely at the door to the pent-shack, then threw himself flat, clawing at the tarpaper. There was a mounting roar. The top of the water tank went spinning off like a flying saucer. Momentarily, as if it were a giant syringe, the whirlwind dipped into the tank. Simon felt himself sliding across the roof, felt his legs lifting. He fetched up against the roof's low wall and at that moment the wind let go of him and his legs touched tarpaper again. Gaining his feet numbly, Simon staggered into the leaning pent-shack. The pale man was nowhere to be seen, the plush chair empty. The curtain at the other side of the room had fallen with its rods, revealing a bathtub more antique than Simon's. In the tub, under the window, sat Grushenka. The lightning flares showed her with her chin level with the water, her eyes placidly staring, her mouth opening and closing. Simon found himself putting his arms around the black-clad figure. With a straining effort he lifted her out of the tub, water sloshing all over his legs, and half carried, half slid with her down the stairs. He fetched up panting and disheveled at the top landing, his attention riveted by the lightning-illuminated scene in the two-story-high living room below. At the far end of it a dark-robed figure crouched at the console of the mighty organ, like a giant bat at the base of the portico of a black and gold temple. In the center of the room Ivan was in the act of heaving above his head his globular leather case. Mikhail darted a look over his shoulder and sprang to one side. The projectile crashed against the organ. Mikhail picked himself up, tearing something from his neck. Ivan lunged forward with a roar. Mikhail crashed a fist against his jaw. The Bomber went down and didn't come up. Mikhail unwrapped his crucifix from his fingers and resumed playing. With a wild cry Simon heaved himself to his feet, stumbled over Grushenka's sodden garments, and pitched headlong down the stairs. When he came to, the house was empty and the Stulnikov moving van was gone. At the front door he was met by a poker-faced young man who identified himself as a member of the FBI. Simon showed him the globular case Ivan had thrown at the organ. It proved to contain a bowling ball. The young gentleman listened to his story without changing expression, thanked him warmly, and shooed him out. The Stulnikov-Gureviches disappeared for good, though not quite without a trace. Simon found this item in the next evening's paper, the first of many he accumulated yearningly in a scrapbook during the following months: MERMAID RAIN A HOAX, SCIENTIST DECLARES _Milford, Pa._--The "mermaid rain" reported here has been declared a fraud by an eminent European biologist. Vasily Stulnikov-Gurevich, formerly Professor of Genetics at Pire University, Latvia, passing through here on a cross-country trip, declared the miniature "mermaids" were "albino tadpoles, probably scattered about as a hoax by schoolboys." The professor added, "I would like to know where they got them, however. There is clear evidence of mutation, due perhaps to fallout." Dr. Stulnikov directed his party in a brief but intensive search for overlooked specimens. His charming silent sister, Grushenka Stulnikov, wearing a quaint Latvian swimming costume, explored the shallows of the Delaware. After collecting as many specimens as possible, the professor and his assistants continued their trip in their unusual camping car. Dr. Stulnikov intends to found a biological research center "in the calm and tolerant atmosphere of the West Coast," he declared. 
32492	----	ENDLESS AMUSEMENT: A COLLECTION OF NEARLY 400 ENTERTAINING EXPERIMENTS IN VARIOUS BRANCHES OF SCIENCE; INCLUDING ACOUSTICS, ELECTRICITY, MAGNETISM, ARITHMETIC, HYDRAULICS, MECHANICS, CHEMISTRY, HYDROSTATICS, OPTICS; WONDERS OF THE AIR-PUMP; ALL THE POPULAR TRICKS AND CHANGES OF THE CARDS, &c., &c. TO WHICH IS ADDED, A COMPLETE SYSTEM OF PYROTECHNY; OR, THE ART OF MAKING FIRE-WORKS. THE WHOLE SO CLEARLY EXPLAINED AS TO BE WITHIN THE REACH OF THE MOST LIMITED CAPACITY. With Illustrations. FROM THE SEVENTH LONDON EDITION. PHILADELPHIA: LEA AND BLANCHARD. 1847. CONTENTS. Page Aces, the convertible 117 Æolipiles 60 Aigrettes 185 Air-pump 77 bottles broken by 77 glass broken by 77 hand fixed by 77 water boiled by 78 bubbles, vegetable 78 electrified 98 Alarum 147 Alphabet, changes of, in square Yards 59 Apparition, armed 126 Atmosphere, to show the Pressure of 137 Aurora Borealis, electric 91 Bacchus, animated 81 Ball, electrified 97 electric 99 Balloon, artificial 81 electric 96 Cases in Fire-works 184 Balloons, Paper, to construct 42 in Fire-works, to load with Stars, Serpents, &c. 184 Balls, dancing 93 Barley, the Awn of, an Hydrometer 157 Bell, magic 79 Bladder, exploded 80 cemented 81 Blue, to change to White 35 Bodies, two inodorous, become pungent by Mixture 145 Body, combustible, to ignite by reflection 57 Bottle, magic 48 enchanted 59 Bronzing, the Art of 133 Bubble, exploding 13 Bubbles, aërial 78 Burning-glasses, account of two 32 Busts, talking 61 Butterflies, to take Impressions of on Paper 134 Cameleon Spirit 23 Camera Obscura, to construct 16 Camphor, electrified 100 Candle lighted by electricity 84 Bombs 84 Card, divining 107 numerical 108 hit upon by guess 109 found by the Point of a Sword 109 changed by Word of Command 109 in the Ring 112 in the Mirror 113 in the Opera-glass 113 discovered by the throw of a Die 115 under the Handkerchief 117 to tell that a person has touched 117 in the Pocket-book 118 in the Egg 118 discovered by the Touch or Smell 119 Cards, magnetic 71 Amusements with 101 Points on three, to name, &c. 101 to tell how many taken from a Pack 102 to name several fixed on 104 to name the Rank of, drawn from a Piquet Pack 104 to tell the Numbers of any two 105 three 106 four confederate 108 to separate the two Colours of a Pack of, at one Cut 114 metamorphosed 114 Number of, told by their Weight 116 to change, that several persons have drawn from the Pack 116 inverted 119 transmutable 119 convertible 120 Cascade, magical 50 musical 148 of fire, to represent 151 Cement, never-yielding 37 Changes on twelve Bells 58 Charcoal for Fire-works 164 Chase, magic 88 Coins, to take impressions of 44 Compositions for Fire-works, method of mixing 168 Concerto, solar 62 Cork heavier than Lead 81 Correspondence, secret 18, 25 by music 20 Coruscations, artificial 136 Cotton electrified 92 Crackers, to make 169 Cylinder, illuminated 91 Dance, magic 86 Dancer, hydraulic 49 Detonating works 190 Girdle 190 Balls 191 Tape 191 Cards 191 Dial, magnetic 71 Dodecahedron in Fire-works 187 Duplicates, ten 102 Earthquake, artificial 22, 86, 187 Eclipse of the Sun, to observe 129 Egg, to form Figures on, in Relief 35 Eggs, white of, contains an Alkali 144 Electric effects of a Russian climate 30 Electricity, experiments in 83 Resin lighted by 95 Spirits ignited by 95 Eolian Harp, to make 137 Exhalations, subaqueous 137 Explosion, brilliant, under Water 54 Explosion, magical 86 electric 98 Feather, animated 83 Feathers heavier than Lead 79 Figures, two, one blows out, and the other re-lights a Candle 39 Fire produced by the mixture of two cold Liquids 13 from Cane 136 Fire-pumps in Fire-works 186 Fire-works in miniature 27 imitative 149 Art of making 163 aquatic 192 Flash of Lightning, to resemble on entering a Room 37 Flower, to produce the Appearance of, from its Ashes 149 Flowers, restored 26 to diversify the Colours of 141 Fountain, fiery 44 globular 48 illuminated 51 which acts by the Heat of the Sun 52 magic 80 electrical 87 Fountains, Chinese, in Fire-works 187 Fruit, withered, restored 78 Fulminating Powders 33 more powerful 34 Gold 40 Mercury 54 Gas Bubbles, exploding 160 Ghastly Appearance, to give to Persons in a Room 35 Glass, so to fill with Water that it cannot be removed without spilling the whole 38 Gold Chain, old, to make look like new 43 to give Silver the Colour of 43 Guinea, penetrative 132 Gunpowder 165 exploded by reflection 125 Brimstone and Charcoal, to meal for Fire-works 165 Halo, artificial 80 Horn, to make Moulds of 134 to soften 134 Hour of the Day or Night told by a suspended Shilling 152 Hydrogen Gas, to procure 159 to fill a Bladder with 159 Illuminations, artificial 22 chemical 36 Illusion, alternate 146 Incendiary, unconscious 88 Indromacus 103 Ink, invisible 23 Gold, Silver, Yellow, Red, Green, Violet, and Grey 24, 25 secret Correspondence by Means of 25 golden 41 white 42 Iron, transformed into Copper 36 Silver 36 melted in a Moment and run into Drops 37 or Steel, to soften 135 Ivory, to cast Figures in Imitation of 134 Kings, the four inseparable 116 Kite, electric 87 Lamp to burn twelve Months without replenishing 29 Chronometer 46 Landscape, artificial 66 to draw correctly 67 Lead, metallic, produced from the Powder 141 Leech, a Prognosticator of Weather 157 Leyden Phial 94 Light, rays of 143 refraction of 144 travelling of 145 Lightning, artificial 14 its wonderful Nature 144 to guard against 153 Liquor that shines in the Dark 40 luminous 41 Luminaries, miraculous 89 Magic Lantern, Experiment with the 62 Glasses to paint 63 solar 60 Magnetism, Experiments in 70 Memory, artificial 158 Microscope, Experiment for the 145 Mirror, Magician's 124 perspective 124 distorting 126 oracular 152 Mirrors, magical 53 deforming 123 igniting 125 Money augmented by optical Illusion 15 melted in a Walnut-shell 40 Mortars, in Fire-works 184 Neptune in his Chariot 198 Number, to tell any, privately fixed on 45 without asking questions 45 divisible by 9, &c. 55 Numbers, to find the difference of two, &c. 56 Objects, three, discernible only with both Eyes 15 Oil upon Water, and Water upon Oil, curious Effects of 161 and Water, Experiments with 161 Opaque Bodies, seemingly transparent 121 Box made transparent 130 Opera-glass, diagonal 129 Oracle, inanimate 61 Orrery, magnetic 72 electrical 92, 99 Palace, enchanted 120 Parties, three magical 110 Paradox, dioptrical 127 Pass, how to make the 107 Perspective-glass, divining 111 Phantom 126 Phial of the four Elements 48 Philosophical Candle 37 Phosphorus Match Bottles 34 inflammable 53 Phosphorus, illuminated 97 Picture, magic 13 Pictures of Birds, to make, with their natural Feathers 132 Pieces, transposable 131 Plants, remarkable Properties in 138 Plaster of Paris cast, to take from a Person's Face 135 Pomatum, to make, with Wax and Water 36 Portrait, miraculous 85 Powder, which catches Fire when exposed to the Air 39 Prints, to remove Stains from 38 Prospect, boundless 57 Prospects, illuminated 68 Pyrotechny, a complete system of 163 Rain and Hail, artificial 28 Gauge, to make 142 Rainbow, artificial 60 Reflector, magnifying 16 Ring, to suspend by a Thread after the Thread has been burnt 35 on the Finger, to name, &c. 49 Roman Candles, in Fire-works 186 Rocket Stars 173 to fix one on the Top of another 174 Rockets 170 Method of rolling 170 Composition for 171 to drive 171 Decorations for 172 Caduceous 175 Honorary 175 which form an arch in rising 176 to make several rise together 176 to fix several on the same Stick 177 to fire without Sticks 178 Scrolls for 179 Stands for 179 Table 179 Water 192 Rose, changeable 41 Resin lighted by Electricity 95 Salt, exploding 127 Saltpetre for Fire-works 164 Saltpetre, to pulverize for Fire-works 164 Sealing-wax spun into Threads by Electricity 100 Sea-fight, &c. in Aquatic Fire-works 196 Serpents, for Fire-works, to make 169 Shillings, a Person having an even number of in one Hand, and an odd Number in the other, to tell in which Hand the odd or even Number is 17 Shock, inconceivable 88 Shower, mercurial 80 fiery 90 Silver-plate, to give a Lustre to 44 extracted from a gilded Ring 135 Sky-rockets 170 to fire under Water 198 Sound, travelling of 141, 142 Sparks, electric 93 in choked Cases 167 Sparrows, Experiments with 82 Spectre on the Table 64 Spider, artificial 84 Spirit, Cameleon 23 Spots in the Sun's Disk, to show 128 Spur-fire 166 Square Yards, to contain the Changes of the Alphabet 59 Squares, Magic 55 Squibs, to make 169 Stars, with Points, in Fire-works 188 Steam, Power of 31 Steel or Iron, to soften 135 Stone, floating 78 Storm at Sea, to represent by the Magic Lantern 63 Sulphur for Fire-works 163 Sun, fixed, with a transparent Face 189 Sun's Rays, Effects of, on different coloured Cloths 146 Swans and Ducks in Aquatic Fire-works 199 Tantalus, Cup of 85 Thunder, artificial 14, 15 Touch-paper, to make 167 Transcolorations, curious 29, 30 Transmutations, magical 35 Travelling of Sound 141, 142 Light 145 Tree, Silver 27 Tree, Lead 27 Iron 55 sublimated 139 Tube, Magic 123 Tulip, Experiment with 140 Vacuum, illuminated 90 Vase, Magic 110 Vessel, Magic 21 that lets Water out of the Bottom as soon as the Mouth is uncorked 39 Verse, Magic 74 Viper, Experiment with 82 Visual Nerves, singular Impression on, by a luminous Object 160 by looking through differently-coloured Glasses 161 Volcano, artificial 22 Wand, magnetic 70 mercurial 79 Watch Dial, to tell by one the Hour when a Person intends to rise 17 mysterious 70 Lamp 140 Water gilding on Silver 43 which gives Silver a Gold Colour 43 to give any Metal a Gold Colour 43, 44 Sun 50 illuminated 96 colder than Ice 127 Experiment with a Glass of 135 beautifully transparent 142 Power of 143 in Steam 158 Pressure of 143 Mass of, contained in the Sea 145 Rockets 192 Wheels, horizontal 193 Pipes in Fire-works 193 Mines 194 Fire Globes 194 Balloons, odoriferous 195 Fire Fountains 200 Weather, to foretel 140 Table 162 Wheels, self-moving 79, 94 in Fire-works 180 single vertical 180 horizontal 181 plural 182 spiral 182 Balloon 183 double spiral 183 illuminated spiral 183 Winter, changed to Spring 26 Writing, mysterious 26 illuminated 28 burnt, restored 129 in the Dark, to make luminous 139 on Glass by the Rays of the Sun 148 ENDLESS AMUSEMENT. _To produce Fire by the Mixture of two cold Liquids._ Take half a pound of pure dry nitrate, in powder; put it into a retort that is quite dry; add an equal quantity of highly rectified oil of vitriol, and, distilling the mixture in a moderate sand heat, it will produce a liquor like a yellowish fume; this, when caught in a dry receiver, is _Glauber's Spirits of Nitre_; probably the preparation, under that name, may be obtained of the chemists, which will of course save much time and trouble. You then put a drachm of distilled oil of cloves, turpentine, or carraways, in a glass vessel; and if you add an equal quantity, or rather more, of the above spirit, though both are in themselves perfectly cold, yet, on mixing them together, a great flame will arise and destroy them both, leaving only a little resinous matter at the bottom. _The Exploding Bubble._ If you take up a small quantity of melted glass with a tube, (the bowl of a common tobacco-pipe will do,) and let a drop fall into a vessel of water, it will chill and condense with a fine spiral tail, which being broken, the whole substance will burst with a loud explosion, without injury either to the party that holds it, or him that breaks it; but if the _thick_ end be struck, even with a hammer, it will not break. _The Magic Picture._ Take two level pieces of glass, (plate glass is the best,) about three inches long and four wide, exactly of the same size; lay one on the other, and leave a space between them by pasting a piece of card, or two or three small pieces of thick paper, at each corner. Join these glasses together at the edges by a composition of lime slaked by exposure to the air, and white of an egg. Cover all the edges of these glasses with parchment or bladder, except at one end, which is to be left open to admit the following composition. Dissolve, by a slow fire, six ounces of hogs'-lard, with half an ounce of white wax; to which you may add an ounce of clear linseed oil. This must be poured in a liquid state, and before a fire, between the glasses, by the space left in the sides, and which you are then to close up. Wipe the glasses clean, and hold them before the fire, to see that the composition will not run out at any part. Then fasten with gum a picture or print, painted on very thin paper, with its face to one of the glasses, and, if you like, you may fix the whole in a frame. While the mixture between the glasses is cold, the picture will be quite concealed, but become transparent when held to the fire; and, as the composition cools, it will gradually disappear. _Artificial Lightning._ Provide a tin tube that is larger at one end than it is at the other, and in which there are several holes. Fill this tube with powdered resin; and when it is shook over the flame of a torch, the reflection will produce the exact appearance of lightning. _Artificial Thunder._ Mix two drachms of the filings of iron, with one ounce of concentrated spirit of vitriol, in a strong bottle that holds about a quarter of a pint; stop it close, and in a few minutes shake the bottle; then taking out the cork, put a lighted candle near its mouth, which should be a little inclined, and you will soon observe an inflammation arise from the bottle, attended with a loud explosion. To guard against the danger of the bottle bursting, the best way would be to bury it in the ground, and apply the light to the mouth by means of a taper fastened to the end of a long stick. _Another way._ Mix three ounces of saltpetre, two ounces of salt of tartar, and two ounces of sulphur; roll the mixture up into a ball, of which take a quantity, about the size of a hazel-nut, and, placing it in a ladle or shovel over the fire, the explosion will resemble a loud clap of thunder. You will produce a much more violent commotion if you double or treble the quantity of the last experiment; suppose you put two or three ounces of the mixture into the shovel. For fear of accidents, it should not be done in the house, but by placing the shovel over a chafing-dish of very hot coals, in the open air, standing a great distance off. Common prudence will dictate the necessity of using great care in the above experiments, as an accident will soon happen if a person does not get out of the way before the composition explodes. _Money augmented by an Optical Illusion._ In a large drinking-glass of a conical shape, (small at the bottom and wide at the top,) put a shilling, and let the glass be half full of water; then place a plate on the top of it, and turn it quickly over, that the water may not escape. You will see on the plate a piece of coin of the size of half-a-crown; and a little higher up another the size of a shilling. It will add to the amusement this experiment affords, by giving the glass to any one in company, (but who, of course, has not witnessed your operations,) and, desiring him to throw away the water, but save the pieces, he will not be a little surprised at finding only one. _Three objects discernible only with both Eyes._ If you fix three pieces of paper against the wall of a room at equal distances, at the height of your eye, placing yourself directly before them, at a few yards' distance, and close your right eye, and look at them with your left, you will see only two of them, suppose the first and second; alter the position of your eye, and you will see the first and third: alter your position a second time, you will see the second and third, but never the whole three together; by which it appears, that a person who has only one eye can never see three objects placed in this position, nor all the parts of one object of the same extent, without altering his situation. _To construct the Camera Obscura._ Make a circular hole in the shutter of a window, from whence there is a prospect of some distance; in this hole place a magnifying glass, either double or single, whose focus is at the distance of five or six feet; no light must enter the room but through this glass. At a distance from it, equal to its focus, place a very white pasteboard, (what is called a Bristol board, if you can procure one large enough, will answer extremely well;) this board must be two feet and a half long, and eighteen or twenty inches high, with a black border round it: bend the length of it inward to the form of part of a circle, whose diameter is equal to double the focal distance of the glass. Fix it on a frame of the same figure, and put it on a moveable foot, that it may be easily placed at that distance from the glass, where the objects appear to the greatest perfection. When it is thus placed, all the objects in front of the window will be painted on the paper in an inverted position, with the greatest regularity, and in the most natural colours. If you place a swing looking-glass outside the window, by turning it more or less, you will have on the paper all the objects on each side the window. If, instead of placing the looking-glass outside the window, you place it in the room above the hole, (which must then be made near the top of the shutter,) you may have the representation on a paper placed horizontally on a table, and draw at your leisure all the objects reflected. Observe, the best situation is directly north; and the best time of the day is noon. _The Magnifying Reflector._ Let the rays of light that pass through the magnifying glass in the shutter be thrown on a large concave mirror, properly fixed in a frame. Then take a third strip of glass, and stick any small object on it; hold it in the intervening rays at a little more than the focal distance from the mirror, and you will see on the opposite wall, amidst the reflected rays, the image of that object, very large, and beautifully clear and bright. _To tell by a Watch Dial the Hour when a Person intends to rise._ The person is told to set the hand of his watch at any hour he pleases, which hour he tells you; and you add in your mind 12 to it. You then desire him to count privately the number of that addition on the dial, commencing at the next hour to that at which he intends to rise, and including the hour at which he has placed the hand, which will give the answer: for example. A intends to rise at 6, (this he conceals to himself;) he places the hand at 8, which he tells B, who, in his own mind, adds 12 to 8, which makes twenty. B then tells A to count twenty on the dial, beginning at the next hour to that at which he proposes to rise, which will be 5, and counting backwards, reckoning each hour as one, and including in his addition the number of the hour the hand is placed at, the addition will end at 6, which is the hour proposed; thus, The hour the hand is placed at is 8 The next hour to that which A intends to rise at is 5, which counts for 1 Count back the hours from 5, and reckon them at 1 each, there will be 11 hours, viz., 4, 3, 2, 1, 12, 11, 10, 9, 8, 7, 6 11 ---- Making 20 _A person having an even Number of Shillings in one Hand, and an odd Number in the other, to tell in which hand the odd or even Number is._ You desire the person to multiply the number in his right hand by an odd figure, and the number in his left by an even one; and tell you if the products, added together, be odd or even. If even, the even number is in the right hand; if odd, the even number is in the left. For instance, I. Number in the right In the left hand _odd_ 7 hand is _even_ 18 Multiply by 2 Multiply by 3 ---- ---- Product 14 Product 54 ---- Add the Product of the left hand 14 ---- Which produces a total of 68 II. Number in the right In the left hand _even_ 18 hand is _odd_ 7 Multiply by 2 Multiply by 3 ---- ---- Product 36 Product 21 Add the Product of the left hand 36 ---- Which produces a total of 57 _Secret Correspondence._ [Illustration: Fig. 1.] To carry on a correspondence without the possibility of the meaning of the letter being detected, in case it should be opened by any other person, has employed the ingenuity of many. No method will be found more effectual for this purpose, or more easy, than the following. Provide a piece of square card or pasteboard, and draw a circle on it, which circle is to be divided into 27 equal parts, in each of which parts must be written _one_ of the capital letters of the alphabet, and the &, as in the figure. Let the centre of this circle be blank. Then draw another circle, also divided into 27 equal parts, in each of which write one of the small letters of the alphabet, and the &. This circle must be cut round, and made exactly to fit the blank space in the centre of the large circle, and must run round a pivot or pin. The person with whom you correspond must have a similar dial, and at the beginning of your letter you must put the capital letter, and at the end the small letter, which answer to each other when you have fixed your dial. Suppose what you wish to communicate is as follows: _I am so watched I cannot see you as I promised; but I will meet you to-morrow in the park, with the letters, &c._ You begin with the letter _T_, and end with the letter _m_, which shows how you have fixed the dial, and how your correspondent must fix his, that he may decipher your letter. Then, for _I am_, you write _b uf_, and so of the rest, as follows. _T b uf lh pumrvayx b rvugghm lyy rhn ul b ikhfblyx vnm b pbee fyym rhn mh-fhkkhp bg may iukd pbma may eymmykl, tw. m._ _Another Way._ Take two pieces of card, pasteboard, or stiff paper, through which you cut long squares at different distances. One of these you keep yourself, and the other you give to your correspondent. You lay the pasteboard on a paper, and, in the spaces cut out, write what you would have understood by him only; then fill the intermediate spaces with any words that will connect the whole together, and make a different sense. When he receives it, he lays his pasteboard over the whole, and those words which are between crotchets [ ] form the intelligence you wish to communicate. For example: suppose you want to express these word, "_Don't trust Robert: I have found him a villain._" "[Don't] fail to send my books. I [trust] they will be ready when [Robert] calls on you. [I have] heard that you have [found] your dog. I call [him a villain] who stole him." You may place a pasteboard of this kind three other ways--the bottom at top--the top at bottom, or by turning it over; but in this case you must previously apprize your correspondent, or he may not be able to decipher your meaning. _Secret Correspondence by Music._ Form a circle like Fig. 2, divided into twenty-six parts, with a letter of the alphabet written in each. The interior of the circle is moveable, like that in Fig. 1, and the circumference is to be ruled like music-paper. Place in each division a note different in figure or position. [Illustration: Fig. 2.] [Illustration: Music Piece] Within the musical lines place the three keys, and on the outer circle the figures to denote time. Then get a ruled paper, and place one of the keys (suppose _ge-re-sol_) against the time 2-4ths, at the beginning of the paper, which will inform your correspondent how to place his circle. You then copy the notes that answer to the letters of the words you intend to write, in the manner expressed above. _The Magic Vessel._ On the bottom of a vessel, lay three pieces of money, the first at A, the second at B, and the third at C, Fig. 3. Then place a person at D, where he can see no farther into the vessel than E. You tell him, that by pouring water in the vessel you will make him see three different pieces of money; and bid him observe, that you do not convey any money in with the water. But be careful that you pour the water in very gently, or the pieces will move out of their places, and thereby destroy the experiment. [Illustration: Fig. 3.] When the water rises up to F, the piece at A will be visible; when it reaches G, both A and B will be visible; and when it comes up to H, all three pieces will be visible. _Artificial Earthquake and Volcano._ Grind an equal quantity of fresh iron filings with pure sulphur, till the whole be reduced to a fine powder. Be careful not to let any wet come near it. Then bury about thirty pounds of it a foot deep in the earth, and in about six or eight hours the ground will heave and swell, and shortly after send forth smoke and flames like a burning mountain. If the earth is raised in a conical shape, it will be no bad miniature resemblance of one of the burning mountains. _Artificial Illuminations._ A very pleasing exhibition may be made with very little trouble or expense, in the following manner: Provide a box, which you fit up with architectural designs cut out on pasteboard; prick small holes in those parts of the building where you wish the illuminations to appear, observing, that in proportion to the perspective, the holes are to be made smaller; and on the near objects the holes are to be made larger. Behind these designs thus perforated, you fix a lamp or candle, but in such a manner that the reflection of the light shall only shine through the holes; then placing a light of just sufficient brilliance to show the design of the buildings before it, and making a hole for the sight at the front end of the box, you will have a very tolerable representation of illuminated buildings. The best way of throwing the light in front, is to place an oiled paper before it, which will cast a mellow gleam over the scenery, and not diminish the effect of the illumination. This can be very easily planned, both not to obstruct the sight, nor be seen to disadvantage. The lights behind the picture should be very strong; and if a magnifying glass were placed in the sight hole, it would tend greatly to increase the effect. The box must be covered in, leaving an aperture for the smoke of the lights to pass through. The above exhibition can only be shown at candle-light; but there is another way, by fixing small pieces of gold on the building, instead of drilling the holes; which gives something like the appearance of illumination, but by no means equal to the foregoing experiment. N.B. It would be an improvement, if paper of various colours, rendered transparent by oil, were placed between the lights behind and the aperture in the buildings, as they would then resemble lamps of different colours. _The Cameleon Spirit._ Put into a decanter volatile spirit, in which you have dissolved copper filings, and it will produce a fine blue. If the bottle be stopped, the colour will disappear; but when unstopped, it will return. This experiment may be often repeated. _Invisible Ink._ Put litharge of lead into very strong vinegar, and let it stand twenty-four hours. Strain it off, and let it remain till quite settled; then put the liquor in a bottle. You next dissolve orpiment in quick lime water, by setting the water in the sun for two or three days, turning it five or six times a-day. Keep the bottle containing this liquor well corked, as the vapour is highly pernicious if received into the mouth. Write what you wish with a pen dipped in the first liquor; and, to make it visible, expose it to the vapour of the second liquor. If you wish them to disappear again, draw a sponge or pencil, dipped in aqua fortis, or spirit of nitre, over the paper; and if you wish them to re-appear, let the paper be quite dry, and then pass the solution of orpiment over it. _Another._ Dissolve bismuth in nitrous acid. When the writing with this fluid is exposed to the vapour of liver of sulphur, it will become quite black. _Another._ Dissolve green vitriol and a little nitrous acid in common water. Write your characters with a new pen. Next infuse small Aleppo galls, slightly bruised in water. In two or three days, pour the liquor off. By drawing a pencil dipped in this second solution over the characters written with the first, they will appear a beautiful black. _Invisible Gold Ink._ Put as much gold in as small a quantity of aqua regia as will dissolve it, and dilute it with two or three times the quantity of distilled water. Next dissolve, in a separate vessel, fine pewter in aqua regia, and when it is well impregnated, add an equal quantity of distilled water. Write your characters with the first solution: let it dry in the shade. To make them visible, draw a pencil or sponge, dipped in the second solution, over the paper, and the characters will appear of a purple colour. _Invisible Silver Ink._ Dissolve fine silver in aqua fortis; and after the dissolution, add some distilled water in the same manner as in the gold ink. What is written with the above ink will remain invisible for three or four months, if kept from the air; but may be easily read in an hour, if exposed to the fire, air, or sun. _Invisible Yellow Ink._ Steep marigold flowers seven or eight days in clear distilled vinegar. Press the flowers and strain the liquor, which is to be kept in a bottle well corked. If you would have it still more clear, add, when you use it, some pure water. To make the characters visible, which you write with this ink, pass a sponge over the paper, dipped in the following solution: Take a quantity of flowers of pansy, or the common violet, bruise them in a mortar with water, strain the liquor in a cloth, and keep it in a bottle. _Invisible Red Ink._ To the pure spirit of vitriol or nitre, add eight times as much water. Use the above solution of violets to make visible the characters written with this ink. _Invisible Green Ink._ Dissolve salt of tartar, clean and dry, in a sufficient quantity of river water. Use the violet solution to render it visible. _Another Invisible Green Ink._ Dissolve zaffre, in powder, in aqua regia, for twenty-four hours. Pour the liquor off, and the same quantity of common water, and keep it in a bottle well corked. This ink will not be visible till exposed to the fire or the sun; and will again be invisible when it becomes cold. _Invisible Violet Ink._ Express the juice of lemons, and keep it in a bottle well corked. Use the violet infusion to make the writing visible. _Invisible Grey Ink._ Mix alum with lemon-juice. The letters written with this ink will be invisible till dipped in water. * * * * * We now present our readers with a variety of amusing experiments, which may be performed by the foregoing inks; and they will, probably, suggest others equally amusing and useful. _A Secret Correspondence by means of Invisible Ink._ A person wishing to carry on a correspondence with another, and who is fearful of having his letter opened, or intercepted, can adopt the following plan: Write any unimportant matter with common ink, and let the lines be very wide apart: then between these lines write the communication you wish to make, with any of the above invisible inks you can most readily procure. Your correspondent is to be previously apprized of the method of making the characters visible: and writing in common ink will serve to lull the suspicions of those who might intercept the letter, and who, not finding any thing important in it, will either forward or keep it. In either case there can be no danger, as the writing will not be visible without the proper application. _The Mysterious Writing._ Write on a piece of paper with common ink any question; then underneath it write the answer either in invisible silver ink, or the invisible green ink, made with zaffre and aqua regia, described in pages 24 and 25. You give this paper to your friend, and tell him to place it against the wall, or on his dressing-table, keeping the door locked, that he may be sure no person has entered his room: he will next day find the answer written on it. _The Restored Flowers._ Make a bouquet of artificial flowers; the leaves should be formed of parchment. Dip the roses in the red invisible ink, the jonquilles in the yellow, the pinks in the violet, and the leaves in the green ink. They will all appear white; and you show them to the company, observing, that you will restore them to their natural colours, and desiring any person to fix any private mark on them he pleases, that he may be sure there is no deception. You then, unperceived by the company, dip them in the revivifying liquor, used to make the yellow ink visible, described in page 24, and, drawing them gently out, that the liquor may drop, and the flowers have time to acquire their colours, you present them to the company, who will see, with surprise, that they each appear in their natural colours. _Winter changed to Spring._ Take a print that represents winter, and colour those parts which should appear green, with the second green invisible ink, described in page 25; observing, of course, the usual rules of perspective, by making the near parts deeper in colour than the others. The other objects must be painted in their natural colours. Then put the print into a frame with a glass, and cover the back with a paper that is pasted only at its extremities. When this print is exposed to a moderate fire, or the warm sun, the foliage, which appeared covered with snow, will change to a pleasing green; and if a yellow tint be thrown on the lighter parts before the invisible ink is drawn over it, this green will be of different shades. When it is exposed to the cold, it will again resume its first appearance of winter. _The Silver Tree._ Dissolve an ounce of fine silver in three ounces of strong aqua fortis, in a glass bottle. When the silver is dissolved; pour the aqua fortis into another glass vessel, (a decanter will be best,) with seven or eight ounces of mercury, to which add a quart of common water; to the whole add your dissolved silver, and let it remain untouched. In a few days the mercury will appear covered with a number of little branches of a silver colour. This appearance will increase for a month or two, and will remain after the mercury is entirely dissolved. _The Lead Tree._ A more modern invention, and an easier method by far than the above, is the following: To a piece of zinc fasten a wire, crooked in the form of the worm of a still; let the other end of the worm be thrust through a cork. You then pour spring water into a phial or decanter, to which you add a small quantity of sugar of lead; thrust the zinc into the bottle, and with the cork at the end of the wire fasten it up. In a few days the tree will begin to grow, and produce a most beautiful effect. _To produce beautiful Fire-works in Miniature._ Put half a drachm of solid phosphorus into a large pint Florence flask; holding it slanting, that the phosphorus may not break the glass. Pour upon it a gill and a half of water, and place the whole over a tea-kettle lamp, or any common tin lamp, filled with spirit of wine. Light the wick, which should be almost half an inch from the flask; and as soon as the water is heated, streams of fire will issue from the water by starts, resembling sky-rockets; some particles will adhere to the sides of the glass representing stars; and will frequently display brilliant rays. These appearances will continue at times till the water begins to simmer, when immediately a curious aurora borealis begins, and gradually ascends, till it collects to a pointed flame; when it has continued half a minute, blow out the flame of the lamp, and the point that was formed will rush down, forming beautiful illuminated clouds of fire, rolling over each other for some time, which disappearing, a splendid hemisphere of stars presents itself: after waiting a minute or two, light the lamp again, and nearly the same phenomenon will be displayed as from the beginning. Let the repetition of lighting and blowing out the lamp be made for three or four times at least, that the stars may be increased. After the third or fourth time of blowing out the lamp, in a few minutes after the internal surface of the flask is dry, many of the stars will shoot with great splendour, from side to side, and some of them will fire off with brilliant rays; these appearances will continue several minutes. What remains in the flask will serve for the same experiment several times, and without adding any more water. Care should be taken, after the operation is over, to lay the flask and water in a cool, secure place. _Artificial Rain and Hail._ Make a hollow cylinder of wood; let it be very thin at the sides, about eight or ten inches wide, and two or three feet diameter. Divide its inside into five equal parts, by boards of five or six inches wide, and let there be between them and the wooden circle, a space of about one-sixth of an inch. You are to place these boards obliquely. In this cylinder put four or five pounds of shot that will easily pass through the opening. When turned upside down, the noise of the shot going through the various partitions will resemble rain; and if you put large shot, it will produce the sound of hail. _Illuminated Writing._ It is well known that if any words are written on a wall with solid phosphorus, the writing will appear as if on fire; but it is necessary to give this caution, lest accidents should occur. In using it, let a cup of water be always near you; and do not keep it more than a minute and a half in your hand, for fear the warmth of your hand should set it on fire. When you have written a few words with it, put the phosphorus into the cup of water, and let it stay a little to cool; then take it out, and write with it again. _A Lamp that will burn Twelve Months without replenishing._ Take a stick of phosphorus, and put it into a large dry phial, not corked, and it will afford a light sufficient to discern any object in a room when held near it. The phials should be kept in a cool place, where there is no great current of air, and it will continue its luminous appearance for more than twelve months. _Curious Transcolorations._ Put half a table-spoonful of syrup of violets and three table-spoonfuls of water into a glass; stir them well together with a stick, and put half the mixture into another glass. If you add a few drops of acid of vitriol into one of the glasses and stir it, it will be changed into a crimson; put a few drops of fixed alkali dissolved into the other glass, and when you stir it, it will change to green. If you drop slowly into the green liquor, from the side of the glass, a few drops of acid of vitriol, you will perceive crimson at the bottom, purple in the middle, and green at the top; and by adding a little fixed alkali dissolved, to the other glass, the same colours will appear in different order. _Another._ If you put a tea-spoonful of a liquor composed of copper infused in acid of vitriol, into a glass, and add two or three table-spoonfuls of water to it, there will be no sensible colour produced; but if you add a little volatile alkali to it, and stir it, you will perceive a very beautiful blue colour. Add a little acid of vitriol, the colour will instantly disappear upon stirring it; and by adding a little fixed alkali dissolved, it will return again. _Another._ Put half a tea-spoonful of a liquor composed of iron infused in acid of vitriol, into half a glass of water; and add a few drops of phlogisticated alkali, and a beautiful Prussian blue will appear. _Curious Account of the Electric Effects of a Russian Climate._ Mr. Æpinus in a letter to Dr. Guthrie, relates the following phenomena, which took place in Russia, when a severe frost had continued for several weeks. Mr. Æpinus was sent for to the palace to see an uncommon phenomenon. On going into the apartment of Prince Orloff, he found him at his toilet, and that every time his valet drew the comb through his hair, a strong crackling noise was heard; and on darkening the room, sparks were seen following the comb in great abundance, while the prince himself was so completely electrified, that strong sparks could be drawn from his hands and face; nay, he was even electrified when he was only powdered with a puff. A few days after, he was witness to a more striking effect of the electric state of a Russian atmosphere. The Grand Duke of Russia sent for him one evening in the twilight, and told him, that having briskly drawn a flannel cover off a green damask chair in his bed-chamber, he was astonished at the appearance of a strong bright flame that followed; but considering it as an electrical appearance, he had tried to produce a similar illumination on different pieces of furniture, and could then show him a beautiful and surprising experiment. His highness threw himself on his bed, which was covered with a damask quilt, laced with gold; and, rubbing it with his hands in all directions, the young prince, who had then reached his twelfth year, appeared swimming in fire, as at every stroke flames arose all around him, darted to the gold-laced border, ran along it, and up to that of the bed, and even to the very top. While he was showing this experiment, Prince Orloff came into the room, with a sable muff in his hand, and showed us, that by only whirling it five or six times round his head in the air, he could electrify himself so strongly, as to send out sparks from all the uncovered parts of his body. _Astonishing Power of Steam._ If you put a small quantity of water into a tea-kettle, and place it on the fire, it will disappear in a short time, having escaped in the steam. But if its escape be prevented by stopping up the spout and crevices, it will force its way by bursting the vessel in which it was confined. If the steam of boiling water be at liberty, the water never attains more than a certain degree of heat; but if confined in a close vessel, the additional fire not escaping, the power of the steam is increased, it re-acts upon the water, and raises the heat so much higher, that it would keep lead in a melting state; and so penetrating, that it would soften the marrow-bone of an ox, in a few minutes. There is an instrument contrived for the foregoing purposes, called Papin's Digester, from the name of its inventor, and from its digestive powers on substances exposed to its action. It is a very strong vessel, made of copper, fitted with a thick close cover, and fastened down by several strong screws, so as to render it steam-tight in great degrees of heat. To render it safe, while being used, there is a valve on the cover, to let out the steam, when it is too violent; this valve is kept down by a steel-yard, with a weight moveable upon it, to regulate the degrees of the steam within. The following account of an accident with one of these instruments, will give some idea of the great force of steam. Mr. Papin (the inventor) having fixed all things right, and included about a pint of water, with two ounces of marrow-bone, he placed the vessel horizontally between the bars of the grate, about half-way into the fire. In three minutes he found it raised to a great heat, and perceiving the heat in a very short time become more raging, stepped to a side-table for an iron to take the digester out of the fire, when it suddenly burst with the explosion of a musket. It was heard at a considerable distance, and actually shook the house. The bottom of the vessel that was in the fire gave way; the blast of the expanded water blew all the coals out of the fire into the room, the remainder of the vessel flew across the room, and, hitting the leaf of an oak table, an inch thick, broke it all in pieces, and rebounded half the length of the room back again. He could not perceive the least sign of water, though he looked carefully for it; the fire was quite extinguished, and every coal black in an instant. The following accident was attended with more fatal consequences. A steam-engine was repairing at Chelsea, and, as the workmen were endeavouring to discover the defect, the boiler suddenly exploded, and a cloud of steam rushing out at the fracture, struck one of the men who was near it, like a blast of lightning, and killed him in a moment; when his companions endeavoured to take off his clothes, the flesh came off with them from the bones. _Account of the Wonderful Effects of two immense Burning-Glasses._ Mr. de Tschirnhausen constructed a burning-glass, between three and four feet in diameter, and whose focus was rendered more powerful by a second one. This glass melted tiles, slates, pumice-stone, &c., in a moment; pitch, and all resins, were melted even under water; the ashes of vegetables, wood, and other matters, were converted into glass; indeed, it either melted, calcined, or dissipated into smoke, every thing applied to its focus. Mr. Parker, of Fleet-street, made a burning-glass, three feet in diameter; it was formed of flint glass, and when on its frame, exposed a surface of 2 feet 8-1/2 inches to the solar rays. It had a small glass fitted to it, to converge the rays, and heighten the effect. The experiments made by it were more powerful and accurate than those performed by any other glass. The following is a brief epitome of its astonishing power. --------------------------------------+-------+-------+ Substances melted, with their weight; |Weight | Time | and the Time in Seconds, which | in | in | they took in melting. |Grains.|Seconds| --------------------------------------+-------+-------+ Pure gold | 20 | 4 | ---- silver | 20 | 3 | ---- copper | 33 | 20 | ---- platina | 10 | 3 | Nickel | 16 | 3 | A cube of bar-iron | 10 | 12 | --------- cast-iron | 10 | 3 | --------- steel | 10 | 12 | Scoria of wrought-iron | 12 | 2 | Kearsh | 10 | 3 | Cauk, or terra ponderosa | 10 | 7 | A topaz, or chrysolite | 3 | 45 | An oriental emerald | 2 | 25 | Crystal pebble | 7 | 6 | White agate | 10 | 30 | Oriental flint | 10 | 30 | Rough cornelian | 10 | 75 | Jasper | 10 | 25 | Onyx | 10 | 20 | Garnet | 10 | 17 | White rhomboidal spar | 10 | 60 | Zeolites | 10 | 23 | Rotten-stone | 10 | 80 | Common slate | 10 | 2 | Asbestos | 10 | 10 | Common lime-stone | 10 | 55 | Pumice-stone | 10 | 24 | Lava | 10 | 7 | Volcanic clay | 10 | 60 | Cornish moor-stone | 10 | 60 | --------------------------------------+-------+-------+ _Fulminating Powder._ This powder is made by rubbing together, in a hot marble mortar, with a wooden pestle, three parts, by weight, of nitre, two of mild vegetable alkali, and one of flowers of sulphur, till the whole is accurately mixed. If a drachm of this powder be exposed to a gentle heat, in an iron ladle, till it melts, it will explode with a noise as loud as the report of a cannon. _A more powerful fulminating Powder._ The most wonderful instance of chemical detonation is formed by the combination of volatile alkali with silver. Gunpowder, or fulminating gold, are not to be compared with this invention, and the great danger attending its manufacture prevents us from giving a methodical account of its preparation to our readers, particularly as it can be purchased, properly prepared, of the chemists. The slightest agitation or friction is sufficient to cause its explosion. When it is once obtained, it can no longer be touched with safety. The falling of a few atoms of it, from a small height, produces an explosion; a drop of water falling on it has the same effect. No attempt, therefore, can be made to enclose it in a bottle, but it must be let alone in the capsule, wherein, by evaporation, it obtains this terrible property. To make this experiment with safety, no greater quantity than a grain of silver should be used; the last process of drying should be made in a metallic vessel, and the face of the operator defended by a mask with strong glass eyes. _To make the Phosphorus Match Bottles._ Nothing more is necessary for this purpose, than to drop small pieces of dry phosphorus into a common phial; gently heat it till it melts; and then turn the bottle round, that it may adhere to the sides. The phial should be closely corked; and when used, a common brimstone match is to be introduced, and rubbed against the sides of the phial: this inflames the match when it is brought out of the bottle. Though there is no danger in phosphorus, till friction, or fire, is applied, yet persons cannot be too cautious in the use of it, as instances have been known of one of these bottles catching fire in the pocket, and very much endangering the person who carried it; likewise, if carelessly used, small particles are apt to get under the nails, or on the hand; and if, by accident, they are held to the fire, or rubbed together, a flame will presently kindle. _To make a Ring suspend by a Thread, after the Thread has been burned._ Soak a piece of thread in urine, or common salt and water. Tie it to a ring, not larger than a wedding-ring. When you apply the flame of a candle to it, it will burn to ashes, but yet sustain the ring. _To form Figures in relief on an Egg._ Design on the shell any figure or ornament you please, with melted tallow, or any other fat oily substance; then immerse the egg into very strong vinegar, and let it remain till the acid has corroded that part of the shell which is not covered with the greasy matter: those parts will then appear in relief, exactly as you have drawn them. _To give a ghastly Appearance to Persons in a Room._ Dissolve salt in an infusion of saffron and spirits of wine. Dip some tow in this solution, and, having set fire to it, extinguish all other lights in the room. _To change Blue to White._ Dissolve copper filings in a phial of volatile alkali; when the phial is unstopped, the liquor will be blue; when stopped, it will be white. _Magical Transmutations._ Infuse a few shavings of logwood in common water, and when the liquor is sufficiently red, pour it into a bottle. Then take three drinking-glasses, and rinse one of them with strong vinegar; throw into the second a small quantity of pounded alum, which will not be observed if the glass has been recently washed, and leave the third without any preparation. If the red liquor in the bottle be poured into the first glass, it will appear of a straw colour; if into the second, it will pass gradually from bluish-grey to black, when stirred with a key, or any piece of iron, which has been previously dipped in strong vinegar. In the third glass, the red liquor will assume a violet tint. _To make Pomatum with Water and Wax._ Water and wax are two substances that do not naturally unite together; therefore, to those who witness the following process, without knowing the cause, it will have the appearance of marvellous. Put into a new glazed earthen pot, six ounces of river water and two ounces of white wax, in which, you must previously conceal a strong dose of salt of tartar. If the whole be then exposed to a considerable degree of heat, it will assume the consistence of pomatum, and may be used as such. _Iron transformed into Copper._ Dissolve blue vitriol in water, till the water is well impregnated with it; and immerse into the solution small plates of iron, or coarse iron filings. These will be attacked and dissolved by the acid of the vitriol, while the copper naturally contained in the vitriol will be sunk and deposited in the place of the iron dissolved. If the piece of iron be too large for dissolving, it will be so completely covered with particles of copper, as to resemble that metal itself. _Iron transformed into Silver._ Dissolve mercury in marine acid, and dip a piece of iron into it, or rub the solution over the iron, and it will assume a silver appearance. It is scarcely necessary to say, that these transmutations are only apparent, though to the credulous it would seem that they were actually transformed. _Chemical Illuminations._ Put into a middling-sized bottle, with a short wide neck, three ounces of oil or spirit of vitriol, with twelve ounces of common water, and throw into it, at different times, an ounce or two of iron filings. A violent commotion will then take place, and white vapours will arise from the mixture. If a taper be held to the mouth of the bottle, these vapours will inflame and produce a violent explosion, which may be repeated as long as the vapours continue. _The Philosophical Candle._ Provide a bladder, into the orifice of which is inserted a metal tube, some inches in length, that can be adapted to the neck of a bottle, containing the same mixture as in the last experiment. Having suffered the atmospheric air to be expelled from the bottle, by the elastic vapour produced by the solution, apply the orifice of the bladder to the mouth of the bottle, after carefully squeezing the common air out of it, (which you must not fail to do, or the bladder will violently explode.) The bladder will thus become filled with the inflammable air, which, when forced out against the flame of a candle, by pressing the sides of the bladder, will form a beautiful green flame. _To make the appearance of a Flash of Lightning, when any one enters a Room with a lighted Candle._ Dissolve camphor in spirit of wine, and deposit the vessel containing the solution in a very close room, where the spirit of wine must be made to evaporate by strong and speedy boiling. If any one then enters the room with a lighted candle, the air will inflame, while the combustion will be so sudden, and of so short a duration, as to occasion no danger. _To melt Iron in a Moment and make it run into Drops._ Bring a bar of iron to a white heat, and then apply to it a roll of sulphur. The iron will immediately melt and run into drops. This experiment should be performed over a basin of water, in which the drops that fall down will be quenched. These drops will be found reduced into a sort of cast-iron. _Never-yielding Cement._ Calcine oyster-shells, pound them, sift them through a silk sieve, and grind them on porphyry till they are reduced to the finest powder. Then take the whites of several eggs, according to the quantity of the powder; and having mixed them with the powder, form the whole into a kind of paste. With this paste join the pieces of china, or glass, and press them together for seven or eight minutes. This cement will stand both heat and water, and will never give way, even if the article should, by accident, fall to the ground. _To remove Stains and Blemishes from Prints._ Paste a piece of paper to a very smooth clear table, that the boiling water used in the operation may not require a colour which might lessen its success. Spread out the print you wish to clean upon the table, and sprinkle it with boiling water; taking care to moisten it throughout by very carefully applying a very fine sponge. After you have repeated this process five or six times, you will observe the stains or spots extend themselves; but this is only a proof that the dirt begins to be dissolved. After this preparation, lay the print smoothly and carefully into a copper or wooden vessel, larger than the size of the print. Then cover it with a boiling ley of potash, taking care to keep it hot as long as possible. After the whole is cooled, strain off the liquor, take out the print with care, spread it on a stretched cord, and when half dry, press it between leaves of white paper, to prevent wrinkles. By this process, spots and stains of any kind will be effectually removed. _To so fill a Glass with Water, that it cannot be removed without spilling the whole._ This is a mere trick, but may afford some amusement. You offer to bet any person that you will so fill a glass with water that he shall not move it off the table without spilling the whole contents. You then fill the glass, and, laying a piece of paper or thin card over the top, you dexterously turn the glass upside down on the table, and then drawing away the paper, you leave the water in the glass, with its foot upwards. It will therefore be impossible to remove the glass from the table without spilling every drop. _Two Figures, one of which blows out and the other re-lights a Candle._ Make two figures, of any shape or materials you please; insert in the mouth of one a small tube, at the end of which is a piece of phosphorus, and in the mouth of the other a tube containing at the end a few grains of gunpowder; taking care that each be retained in the tube by a piece of paper. If the second figure be applied to the flame of a taper, it will extinguish it; and the first will light it again. _A vessel that will let Water out at the Bottom, as soon as the Mouth is uncorked._ Provide a tin vessel, two or three inches in diameter, and five or six inches in height, having a mouth about three inches in width; and in the bottom several small holes, just large enough to admit a small needle. Plunge it in water with its mouth open, and when full, while it remains in the water, stop it very closely. You can play a trick with a person, by desiring him to uncork it; if he places it on his knee for that purpose, the moment it is uncorked the water will run through at the bottom, and make him completely wet. _A Powder which catches Fire when exposed to the Air._ Put three ounces of rock alum, and one ounce of honey or sugar, into a new earthen dish, glazed, and which is capable of standing a strong heat; keep the mixture over the fire, stirring it continually till it becomes very dry and hard; then remove it from the fire, and pound it to a coarse powder. Put this powder into a long-necked bottle, leaving a part of the vessel empty; and, having placed it in a crucible, fill up the crucible with fine sand, and surround it with burning coals. When the bottle has been kept at a red heat for about seven or eight minutes, and no more vapour issues from it, remove it from the fire, then stop it with a piece of cork; and, having suffered it to cool, preserve the mixture in small bottles well closed. If you unclose one of these bottles, and let fall a few grains of this powder on a bit of paper, or any other very dry substance, it will first become blue, then brown, and will at last burn the paper or other dry substance on which it has fallen. _Fulminating Gold._ Put into a small long-necked bottle, resting on a little sand, one part of fine gold filings, and three parts of aqua regia, (nitro-muriatic acid.) When the gold is dissolved, pour the solution into a glass, and add five or six times the quantity of water. Then take spirit of sal ammoniac or oil of tartar, and pour it drop by drop into the solution, until the gold is entirely precipitated to the bottom of the glass. Decant the liquor that swims at the top, by inclining the glass; and, having washed it several times in warm water, dry it at a moderate heat, placing it on paper capable of absorbing all the moisture. If a grain of this powder, put into a spoon, (it should be an iron one,) be exposed to the flame of a candle, it will explode with a very loud report. _To melt a piece of Money in a Walnut-shell, without injuring the shell._ Bend any thin coin, and put it into half a walnut-shell; place the shell on a little sand, to keep it steady. Then fill the shell with a mixture made of three parts of very dry pounded nitre, one part of flowers of sulphur, and a little saw-dust well sifted. If you then set light to the mixture, you will find, when it is melted, that the metal will also be melted at the bottom of the shell, in form of a button, which will become hard when the burning matter round it is consumed: the shell will have sustained very little injury. _A Liquid that Shines in the Dark._ Take a bit of phosphorus, about the size of a pea; break it into small parts, which you are to put into a glass half full of very pure water, and boil it in a small earthen vessel, over a very moderate fire. Have in readiness a long narrow bottle, with a well-fitted glass stopper, and immerse it, with its mouth open, into boiling water. On taking it out, empty the water, and immediately pour in the mixture in a boiling state; then put in the stopper, and cover it with mastich, to prevent the entrance of the external air. This water will shine in the dark for several months, even without being touched; and, if it be shaken in dry warm weather, brilliant flashes will be seen to rise through the middle of the water. _Luminous Liquor._ Put a little phosphorus, with essence of cloves, into a bottle, which must be kept closely stopped. Every time the bottle is unclosed, the liquor will appear luminous. This experiment must be performed in the dark. _The changeable Rose._ Take a common full-blown rose, and, having thrown a little sulphur finely pounded into a chafing-dish with coals, expose the rose to the vapour. By this process the rose will become whitish; but if it be afterwards held some time in water, it will resume its former colour. _Golden Ink._ Take some white gum arabic, reduce it to an impalpable powder, in a brass mortar; dissolve it in strong brandy, and add a little common water to render it more liquid. Provide some gold in a shell, which must be detached, in order to reduce it to a powder. When this is done, moisten it with the gummy solution, and stir the whole with a small hair-brush, or your finger; then leave it for a night, that the gold may be better dissolved. If the composition become dry during the night, dilute it with more gum water, in which a little saffron has been infused; but take care that the gold solution be sufficiently liquid to flow freely in a pen. When the writing is dry, polish it with a dry tooth. _Another way._ Reduce gum ammoniac into powder, and dissolve it in gum arabic water, to which a little garlic juice has been added. This water will not dissolve the ammonia so as to form a transparent liquid; for the result will be a milky liquor. With the liquor form your letters or ornaments on paper or vellum, with a pen or fine camels'-hair brush; then let them dry, and afterwards breathe on them some time, till they become moist; then apply a few bits of leaf gold to the letters, which you press down gently with cotton wool. When the whole is dry, brush off the superfluous gold with a large camels'-hair brush, and, to make it more brilliant, burnish with a dog's tooth. _White Ink, for Writing on black Paper._ Having carefully washed some egg-shells, remove the internal skin, and grind them on a piece of porphyry. Then put the powder into a small vessel of pure water, and when it has settled at the bottom, draw off the water, and dry the powder in the sun. This powder must be preserved in a bottle; when you want to use it, put a small quantity of gum ammoniac into distilled vinegar, and leave it to dissolve during the night. Next morning the solution will appear exceedingly white; and if you then strain it through a piece of linen cloth, and add to it the powder of egg-shells, in sufficient quantity, you will obtain a very white ink. _To construct Paper Balloons._ Take several sheets of silk paper; cut them in the shape of a spindle; or, to speak more familiarly, like the coverings of the sections of an orange; join these pieces together, into one spherical or globular body, and border the aperture with a ribbon, leaving the ends, that you may suspend them from the following lamp. Construct a small basket of very fine wire, if the balloon is small, and suspend it from the aperture, so that the smoke from the flame of a few leaves of paper, wrapped together, and dipped in oil, may heat the inside of it. Before you light this paper, suspend the balloon in such a manner, that it may, in a great measure, be exhausted of air, and as soon as it has been dilated, let it go, together with the wire basket, which will serve as ballast. _Water-Gilding upon Silver._ Take copper-flakes, on which pour strong vinegar; add alum and salt in equal quantities; set them on a fire, and when the vinegar is boiled, till it becomes one-fourth part of its original quantity, throw into it the metal you design to gild, and it will assume a copper colour. Continue boiling it, and it will change into a fine gold colour. _A Water which gives Silver a Gold Colour._ Take sulphur and nitre, of each an equal quantity; grind them together very fine, and put them into an unglazed vessel; cover and lute it well; then set it over a slow fire for 24 hours; put what remains into a strong crucible, and let it dissolve; put it into a phial, and whatever silver you anoint with it will have a gold colour. _To make an old Gold Chain appear like new._ Dissolve sal ammoniac in urine, boil the chain in it, and it will have a fine gold colour. _To give Silver the Colour of Gold._ Dissolve in common aqua fortis as much silver as you please. To eight ounces of silver, take four ounces of hepatic aloes, six ounces of turmeric, and two ounces of prepared tutty, that has been several times quenched in urine. Put these to the solution of the silver; they will dissolve, but rise up in the glass like a sponge; this glass must therefore be large, to prevent running over. Then draw it off, and you will have ten ounces of silver as yellow as gold. _A Water to give any Metal a Gold Colour._ Take fine sulphur and pulverize it; then boil some stale spring water; pour it hot upon the powder, and stir it well together; boil it again, and pour into it an ounce of dragon's blood. After it is well boiled, take it off, and filter it through a fine cloth; pour this water into a matrass, (a chemical vessel,) after you have put in what you design to colour; close it well, and boil it a third time, and the metal will be a fine gold colour. _Another way._ Take hepatic aloes, nitre, and Roman vitriol, of each equal quantities; and distil them with water, in an alembic, till all the spirits are extracted; it will at last yield a yellowish water, which will tinge any sort of metal of a gold colour. _To give Silver-plate a Lustre._ Dissolve alum in a strong ley, and scum it carefully; then mix it up with soap, and wash your silver utensils with it, using a linen rag. _The Fiery Fountain._ If twenty grains of phosphorus, cut very small, and mixed with forty grains of powder of zinc, be put into four drachms of water, and two drachms of concentrated sulphuric acid be added thereto, bubbles of inflamed phosphoretted hydrogen gas will quickly cover the whole surface of the fluid in succession, forming a real fountain of fire. _To take Impressions of Coins, Medals, &c._ Cut fish-glue, or isinglass, into small pieces, immerse it in clear water, and set it on a slow fire; when gradually dissolved, let it boil slowly, stirring it with a wooden spoon, and taking off the scum. The liquor being sufficiently adhesive, take it off the fire, let it cool a little, and then pour it on the medal or coin you wish to copy, having first rubbed the coin over with oil. Let the composition lay about the thickness of a crown-piece on the medal. Then set it in a moderate air, neither too hot nor too cold, and let it cool and dry. When it is dry, it will loosen itself; you will find the impression correct, and the finest strokes expressed with the greatest accuracy. You may give a most pleasing effect to the composition, by mixing any colour with it, red, yellow, blue, green, &c., and if you add a little parchment size to it, it will make it harder and better. This size is made by gently simmering the cuttings of clear white parchment in a pipkin, with a little water, till it becomes adhesive. _To tell a Person any Number he may privately fix on._ When the person has fixed on a number, bid him double it and add four to that doubling; then multiply the whole by 5; to the product let him add 12, and multiply the amount by 10. From the total of all this, let him deduct 320, and tell you the remainder; from which, if you cut off the two last figures, the number that remains will be what he fixed upon. For instance, Suppose the number chosen is 7 Which doubled 14 Add 4 to it, and it will make 18 Multiply 18 by 5, gives 90 To which add 12, is 102 Multiply that by 10, makes 1020 From which deducting 320, the remainder is 700 And by striking off the two ciphers, it becomes the number thought on 7 _To tell any Number a Person has fixed on, without asking him any Questions._ You tell the person to choose any number from 1 to 15; he is to add 1 to that number, and triple the amount. Then, 1. He is to take the half of that triple, and triple that half. 2. To take the half of the last triple, and triple that half. 3. To take the half of the last triple. 4. To take the half of that half. Thus, it will be seen, there are four cases where the half is to be taken; the three first are denoted by one of the eight following Latin words, each word being composed of three syllables; and those that contain the letter i refer to those cases where the half cannot be taken without a fraction; therefore, in those cases, the person who makes the deduction is to add 1 to the number divided. The fourth case shows which of the two numbers annexed to every word has been chosen; for if the fourth half can be taken without adding 1, the number chosen is in the first column; but if not, it is in the second. _The words._ _The numbers they denote._ Mi-se-ris 8 0 Ob-tin-git 1 9 Ni-mi-um 2 19 No-ta-ri 3 11 In-fer-nos 4 12 Or-di-nes 13 5 Ti-mi-di 6 14 Te-ne-ant 15 7 For example: Suppose the number chosen is 9 To which is to be added 1 ---- 10 The triple of that number is 30 The half of which is 15 The triple of that half must be 45 And the half of that[A] 23 The triple half of that half 69 The half of that[A] 35 And the half of that half[A] 18 [A] At all these stages, 1 must be added, to take the half without a fraction. While the person is performing the operation, you remark, that at the second and third stages he is obliged to add 1; and, consequently, that the word _ob-tin-git_, in the second and third syllables of which is an i, denotes that the number must be either 1 or 9; and, by observing that he cannot take the last half without adding 1, you know that it must be the number in the second column. If he makes no addition at any one of the four stages, the number he chose must be 15, as that is the only number that has not a fraction at either of the divisions. _The Lamp Chronometer._ Figure 4 represents a chamber lamp, A, consisting of a cylindrical vessel made of tin, in the shape of a candle, and is to be filled with oil. This vessel should be about three inches high and one inch diameter, placed in a stand, B. The whole apparatus, of lamp and stand, can be purchased, ready-made, at any tin-shop in London. To the stand, B, is fixed the handle C, which supports the frame D, about 12 inches high, and four inches wide. This frame is to be covered with oiled paper, and divided into 12 equal parts by horizontal lines, at the end of which are written the numbers for the hours, from 1 to 12, and between the horizontal lines, and diagonals, divided into halves, quarters, &c. On the handle C, and close to the glass, is fixed the style or hand E. [Illustration: Fig. 4.] Now, as the distance of the style from the flame of the lamp is only half an inch, then, if the distance of the frame from the style be six inches, while the float that contains the light descends by the decrease on the oil, one inch, the shadow of the style of the frame will ascend 12 inches, being its whole length, and show by its progression, the regular increase of the hours, with their several divisions. You must be careful always to burn the same oil, which must be the best; and the wick must never vary in size; if these precautions are not attended to, the dial never can be accurate. _The Phial of the Four Elements._ Take a phial, six or seven inches long, and about three quarters of an inch in diameter. In this phial put, first, glass coarsely powdered; secondly, oil of tartar per deliquum; thirdly, tincture of salt of tartar; and lastly, distilled rock oil. The glass and the various liquors being of different densities, if you shake the phial, and then let it rest a few moments, the three liquors will entirely separate, and each assume its place; thus forming no indifferent resemblance of the four elements, earth, fire, water, and air: the powdered glass (which should be of some dark colour) representing the earth; the oil of tartar, water; the tincture, air; and the rock oil, fire. _The Magic Bottle._ Take a small bottle, the neck of which is not more than the sixth of an inch in diameter. With a funnel, fill the bottle quite full of red wine, and place it in a glass vessel, similar to a show-glass, whose height exceeds that of the bottle about two inches; fill this vessel with water. The wine will shortly come out of the bottle, and rise in the form of a small column to the surface of the water; while at the same time, the water, entering the bottle, will supply the place of the wine. The reason of this is, that as water is specifically heavier than wine, it must hold the lower place, while the other rises to the top. An effect equally pleasing will be produced, if the bottle be filled with water, and the vessel with wine. _The Globular Fountain._ Make a hollow globe, of copper or lead, and of a size adapted to the quantity of water that comes from a pipe (hereafter mentioned) to which it is to be fixed, and which may be fastened to any kind of pump, provided it be so constructed, that the water shall have no other means of escape than through the pipe. Pierce a number of small holes through the globe, that all tend towards its centre, and annex it to the pipe that communicates with the pump. The water that comes from the pump, rushing with violence into the globe, will be forced out at the holes, and form a very pleasing sphere of water. _The Hydraulic Dancer._ Procure a little figure made of cork, which you may dress as your fancy dictates. In this figure place a small hollow cone made of thin leaf brass. When the figure is placed on a jet d'eau, that plays in a perpendicular direction, it will be suspended on the top of the water, and perform a great variety of amusing motions. If a hollow ball of very thin copper, of an inch diameter, be placed on a similar jet, it will remain suspended, turning round, and spreading the water all about it. _A Person having put a Ring an one of his Fingers, to name the Person, the Hand, the Finger, and the Joint on which it is placed._ Let a third person double the number of the order in which he stands who has the ring, and add 5 to that number; then multiply that sum by 5, and to the product add 10. Let him next add 1 to the last number, if the ring be on the right hand, and 2 if on the left, and multiply the whole by 10: to the product of this he must add the number of the finger, (counting the thumb as the first finger,) and multiply the whole again by 10. Let him then add the number of the joint, and, lastly, to the whole join 35. He is then to tell you the amount of the whole, from which you are to subtract 3535, and the remainder will consist of four figures; the first of which will express the rank in which the person stands, the second the hand, (number 1 signifying the right, and 2 the left,) the third number the finger, and the fourth the joint.--For example: Suppose the person who stands the third in order has put the ring upon the second joint of the thumb of his left hand; then, The double of the rank of the third person is 6 To which add 5 ____ 11 Multiply the sum by 5 ____ 55 To which add 10 And the number of the left hand 2 ____ 67 Which being multiplied by 10 ____ 670 To which add the number of the thumb 1 ____ 671 And multiply again by 10 ____ 6710 Then add the number of the joint 2 And lastly the number 35 ____ 6747 From which deducting 3535 ____ The remainder is 3212 ____ Of which, as we have said, the 3 denotes the third person, the 2 the left hand, the 1 the thumb, and the last 2 the second joint. _The Water Sun._ Provide two portions of a hollow sphere, that are very shallow; join them together in such a manner that the hollow between them be very narrow. Fix them vertically to a pipe from whence a jet proceeds. Bore a number of small holes all around that part where the two pieces are joined together. The water rushing through the holes will form a very pleasing water sun, or star. _The Magical Cascade._ Procure a tin vessel, shaped like Fig. 5, about five inches high and four in diameter, with a cover, C, closed at top. To the bottom of this vessel, let the pipe D E be soldered. This pipe is to be ten inches long, and half an inch in diameter, open at each end, and the upper end must be above the water in the vessel. To the bottom also fix five or six small tubes, F, about one-eighth of an inch in diameter. By these pipes, the water in the vessel is to run slowly out. [Illustration: Fig. 5.] Place this machine in a tin basin, G H, with a hole in the middle, about a quarter of an inch in diameter. Fix to the tube D E, any sort of ornament that will keep the machine firm on the basin, observing, that these supports are sufficiently long to leave about a quarter of an inch between the end of the tube and the orifice in the basin; and let there be a vessel under the basin to catch the water that runs out. As the small pipes discharge more water into the basin than can run out of the central orifice, the water will rise in the basin above the lower end of the pipe, and prevent the air from getting into the vessel, by which the water will cease to flow from the small pipes. But as the water continues to flow from the basin, the air will have liberty again to enter the vessel by the tube, and the water will again flow from the small pipes, and alternately stop and flow, while any water remains in the vessel. As you can guess when the pipes will flow, and when they will stop, you may so manage it, that they will appear to act by word of command. _The illuminated Fountain, that plays when the Candles are lighted, and stops when they are extinguished._ Provide two cylindrical vessels, A B and C D, as in Fig. 6. Connect them by four tubes open at each end, as H I, &c., so that the air may descend out of the higher into the lower vessel. To these tubes fix candlesticks, and to the hollow cover, E F, of the lower vessel, fit a tube, K, reaching almost to the bottom of the vessel. At G let there be an aperture with a screw, whereby water may be poured into C D, which, when filled, must be closed by the screw. [Illustration: Fig. 6.] When the candles are lighted, the air in the upper cover and contiguous pipes will be thereby rarefied, and the jet from the small tube, K, will begin to play: as the air becomes more rarefied, the force of the jet will increase, and it will continue to play till the water in the lower vessel is exhausted. As the motion of the jet is caused by the heat of the candles, when they are extinguished the fountain will stop. _A Fountain which acts by the heat of the Sun._ In the annexed engraving, Fig. 7, G N S is a thin hollow globe of copper, eighteen inches diameter, supported by a small inverted basin, placed on a stand with four legs, A B C D, which have between them, at the bottom, a basin of two feet diameter. Through the leg C passes a concealed pipe, which comes from G, the bottom of the inside of the globe. This pipe goes by H V, and joins the upright pipe _u_ I, to make a jet, as I. The short pipe, _u_ I, which goes to the bottom, has a valve at _u_, under the horizontal pipe H V, and another valve at T, above that Horizontal pipe, under the cock at K. The use of this cock is to keep the fountain from playing in the day, if you think proper. The north pole N of the globe has a screw that opens a hole, whereby water is poured into the globe. [Illustration: Fig. 7.] The machine being thus prepared, and the globe half filled with water, put it in an open place, when the heat of the sun rarefying the air as it heats the copper, the air will press strongly against the water, which, coming down the pipe, will lift up the valve at V, and shut the valve at u. The cock being opened, the water will spout out at I, and continue to play a long while, if the sun shines. _Inflammable Phosphorus._ Take the meal of flour of any vegetable, put it into an iron pan over a moderate fire, and keep it stirring with an iron spoon till it changes to a black powder; to one part of this add four parts of raw alum. Make the whole into a fine powder; put it again into the iron pan, and keep stirring it till it almost catches fire, to prevent its forming into lumps, as it is apt to do when the alum melts; in which case it must be broken again, stirred about, and accurately mixed with the flour, till it emits no more fumes, and the whole appears a fine black powder. Put this powder in a clean dry phial with a narrow neck, filling it to about one-third of the top. Then stop the mouth of the phial with loose paper, so as to let the air pass freely through it, and leave room for the fumes to come through the neck. Place the phial in a crucible, encompassed on all sides with sand, so that it may not touch any part of the crucible, but a considerable space everywhere left between. The phial must be covered up with sand, leaving only a small part bare, by which you can discern whether the powder is ignited. In this state, the crucible is to be surrounded with coals, kindled slowly till it is well heated on all sides, and then the fire is to be raised, till the crucible and every thing in it is red-hot; keep it in this state an hour; after this, the fire still burning as fiercely, close up the orifice of the phial with wax, to exclude the air. Leave it to cool, and you will find in it a black dusty coal formed of the flour and alum. Shake a small quantity of this out of the phial into the cool air, and it will immediately take fire, but will not burn any thing. Keep the bottle dry, as even the air will spoil it effectually. _The Magical Mirrors._ Make two holes in the wainscot of a room, each a foot high and ten inches wide, and about a foot distant from each other. Let these apertures be about the height of a man's head, and in each of them place a transparent glass in a frame, like a common mirror. Behind the partition, and directly facing each aperture, place two mirrors enclosed in the wainscot, in an angle of forty-five degrees.[B] These mirrors are each to be eighteen inches square: and all the space between them must be enclosed with pasteboard painted black, and well closed, that no light can enter; let there be also two curtains to cover them, which you may draw aside at pleasure. When a person looks into one of these fictitious mirrors, instead of seeing his own face he will see the object that is in front of the other; thus, if two persons stand at the same time before these mirrors, instead of each seeing himself; they will reciprocally see each other. There should be a sconce with a lighted candle, placed on each side of the two glasses in the wainscot, to enlighten the faces of the persons who look in them, or the experiment will not have so remarkable an effect. [B] That is, half-way between a line drawn perpendicularly to the ground and its surface. _To cause a brilliant Explosion under Water._ Drop a piece of phosphorus, the size of a pea, into a tumbler of hot water; and, from a bladder furnished with a stop-cock, force a stream of oxygen directly upon it. This will afford a most brilliant combustion under water. _Fulminating Mercury._ Dissolve 100 grains of mercury by heat, in an ounce and a half of nitric acid. This solution being poured cold upon two measured ounces of alcohol previously introduced into any convenient glass vessel, a moderate heat is to be applied, till effervescence is excited. A white fume then begins to appear on the surface of the liquor, and the powder will be gradually precipitated when the action ceases. The precipitate is to be immediately collected on a filter, well washed with distilled water, and cautiously dried in a heat not exceeding that of a water-bath. Washing the powder immediately is material, because it is liable to the re-action of the nitric acid; and, while any of the acid adheres to it, it is very subject to the action of light. From 100 grains of mercury, about 130 of the powder are obtained. This powder, when struck on an anvil with a hammer, explodes with a sharp stunning noise, and with such force as to indent both hammer and anvil. Three or four grains are sufficient for one experiment. _The Iron Tree._ Dissolve iron filings in aqua fortis, moderately concentrated, till the acid is saturated; then add to it gradually, a solution of fixed alkali, (commonly called oil of tartar per deliquum.) A strong effervescence will ensue, and the iron, instead of falling to the bottom of the vessel, will afterwards rise so as to cover the sides, forming a multitude of ramifications heaped one upon the other, which will sometimes pass over the edge of the vessel, and extend themselves on the outside, with all the appearance of a plant. _To make any Number divisible by Nine, by adding a Figure to it._ If (for example) the number named be 72,857, you tell the person who names it to place the number 7 between any two figures of that sum, and it will be divisible by 9; for if any number be multiplied by 9, the sum of the figures of the product will be either 9, or a number divisible by 9. _Arithmetical Squares._ An arithmetical magical square consists of numbers so disposed in parallel and equal lines, that the sum of each, taken any way of the square, amounts to the same. Any five of these sums taken in a right line make 65. You will observe that five numbers in the diagonals A to D, and B to C, of the magical square, answer to the ranks E to F, and G to H, in the natural square, and that 13 is the centre number of both squares. _A Natural Square._ _A Magical Square._ A G B A B +--+--+--+--+--+ +--+--+--+--+--+ | 1| 2| 3| 4| 5| |11|24| 7|20| 3| +--+--+--+--+--+ +--+--+--+--+--+ | 6| 7| 8| 9|10| | 4|12|25| 8|16| +--+--+--+--+--+ +--+--+--+--+--+ E |11|12|13|14|15| F |17| 5|13|21| 9| +--+--+--+--+--+ +--+--+--+--+--+ |16|17|18|19|20| |10|18| 1|14|22| +--+--+--+--+--+ +--+--+--+--+--+ |21|22|23|24|25| |23| 6|19| 2|15| +--+--+--+--+--+ +--+--+--+--+--+ C H D C D To form a magical square, first transpose the two ranks in the natural square to the diagonals of the magical square; then place the number 1 under the central number 13, and the number 2 in the next diagonal downward. The number 3 should be placed in the same diagonal line; but as there is no room in the square, you are to place it in that part it would occupy if another square were placed under this. For the same reason, the number 4, by following the diagonal direction, falling out of the square, it is to be put into the part it would hold in another square, placed by the side of this. You then proceed to numbers 5 and 6, still descending; but as the place 6 should hold is already filled, you then go back to the diagonal, and consequently place the 6 in the second place under the 5, so that there may remain an empty space between the two numbers. The same rule is to observed, whenever you find a space already filled. You proceed in this manner to fill all the empty cases in the angle where the 15 is placed: and as there is no space for the 16 in the same diagonal, descending, you must place it in the part it would hold in another square, and continue the same plan till all the spaces are filled. This method will serve equally for all sorts of arithmetical progressions composed of odd numbers; even numbers being too complicated to afford any amusement. _To find the Difference between two Numbers, the greatest of which is unknown._ Take as many nines as there are figures in the smallest number, and subtract that sum from the number of nines. Let another person add that difference to the largest number, and, taking away the first figure of the amount, add it to the last figure, and that sum will be the difference of the two numbers. For example: Robert, who is 22, tells George, who is older, that he can discover the difference of their ages; he therefore privately deducts 22 from 99, and the difference, which is 77, he tells George to add to his age, and to take away the first figure from the amount, and add it to the last figure, and that last sum will be the difference of their ages. Thus, the difference between Robert's age and 99, is 77 To which George adding his age 35 ---- The sum will be 112 ---- 12 1 ---- Then by taking away the first figure, 1, } and adding it to the last figure, 2, } 13 the sum is } Which added to Robert's age 22 ---- Gives George's age, which is 35 _The Boundless Prospect._ Take a square box, about six inches long and twelve high, or of any other proportionate dimensions. Cover the inside with four flat pieces of looking-glass placed perpendicular to the bottom of the box. Place at the bottom any objects you please, as a piece of fortification, a castle, tents, soldiers, &c. On the top, place a frame of glass shaped like the bottom of a pyramid, as in Fig. 8, and so formed as to fit on the box like a cover. The four sides of this cover are to be composed of ground glass, or covered inside with gauze, so that the light may enter, and yet the inside be invisible, except at the top, which must be covered with transparent glass: when you look through this glass, the inside will present a pleasing prospect of a boundless extent; and, if managed with care, will afford a deal of amusement. [Illustration: Fig. 8.] _To set Fire to a combustible Body by Reflection._ Place two concave mirrors at about twelve feet distance from each other, and let the axis of each be in the same line. In the focus of one of them place a live coal, and in the focus of the other some gunpowder. With a pair of strong bellows keep blowing the coal, and notwithstanding the distance between them, the powder will presently take fire. The mirror may be either made of glass, metal, or pasteboard gilt. _To find the Number of Changes that may be rung on Twelve Bells._ Multiply the numbers from 1 to 12 continually into each other, as follow: and the last product will give the number required. 1 2 -- 2 3 -- 6 4 -- 24 5 ---- 120 6 ---- 720 7 ----- 5,040 8 ------ 40,320 9 ------- 362,880 10 --------- 3,628,800 11 ---------- 39,916,800 12 ----------- 479,001,600 _To find how many square Yards it would require to write all the Changes of the Twenty-four Letters of the Alphabet, written so small, that each Letter should not occupy more than the hundredth part of a square Inch._ By adopting the plan of the preceding article, the changes of the twenty-four letters will be found to be 62,044,840,173,323,943,936,000. Now, the inches in a square yard being 1,296, that number multiplied by 100 gives 129,600, which is the number of letters each square yard will contain; therefore, if we divide the above row of figures, (the number of changes,) by 129,600, the quotient, which is 478,741,050,720,092,160, will be the number of yards required to contain the above mentioned number of changes. But as all the 24 letters are contained in every permutation, it will require a space 24 times as large, _viz._, 11,849,785,210,282,211,840. Now, as the surface of the whole globe only contains 617,197,435,008,000 square yards, it would require a surface 18,620 times as large as the earth to contain them. _The Enchanted Bottle._ Fill a glass bottle with water to the beginning of the neck; leave the neck empty, and cork it. Suspend this bottle opposite a concave mirror, and beyond its focus, that it may appear reversed. Place yourself still further distant from the bottle; and instead of the water appearing, as it really is, at the bottom of the bottle, the bottom will be empty, and the water seen at the top. If the bottle be suspended with the neck downwards, it will be reflected in its natural position, and the water at the bottom, although in reality it is inverted, and fills the neck; leaving the bottom vacant. While the bottle is in this position, uncork it, and let the water run gradually out: it will appear, that while the real bottle is emptying, the reflected one is filling. Care must be taken that the bottle is not more than half or three parts full, and that no other liquid is used but water, as in either of these cases the illusion ceases. _The Solar Magic Lantern._ Make a box, a foot high, eighteen inches wide, and about three inches deep. Two of the opposite sides of this box must be quite open, and in each of the other sides let there be a groove wide enough to admit a stiff paper or pasteboard. You fasten the box against a window, on which the sun's rays fall direct. The rest of the window should be closed up, that no light may enter. Next provide several sheets of stiff paper, blacked on one side. On these papers cut out such figures as your fancy may dictate; place them alternately in the grooves of the box, with their blacked sides towards you, and look at them through a large and clear glass prism; and if the light be strong, they will appear painted with the most lively colours. If you cut on one of these papers the form of a rainbow, about three-quarters of an inch wide, you will have a very good representation of the natural one. For greater convenience, the prism may be placed on a stand on the table, made to turn round on an axis. _The Artificial Rainbow._ Opposite a window into which the sun shines direct suspend a glass globe, filled with clean water, by means of a string that runs over a pulley, so that the sun's rays may fall on it. Then drawing the globe gradually up, you will observe, when it comes to a certain height, and by placing yourself in a proper situation, a purple colour in the glass; and by drawing it up gradually higher, the other prismatic colours, blue, green, yellow, and red, will successively appear; after which, the colours will disappear, till the globe is raised to about fifty degrees, when they will again appear, but in an inverted order, the red appearing first, and the blue or violet last; on raising the globe a little higher, they will totally vanish. _The Æolipiles._ The æolipile is a small hollow globe of brass, or other metal, in which a slender neck or pipe is inserted. This ball, when made red-hot, is cast into a vessel of water, which will rush into its cavity, then almost void of air. The ball being then set on the fire, the water, by the rarefaction of the internal air, will be forced out in steam by fits, with great violence, and with strange noise. If to the necks of two or more of these balls, there be fitted those calls that are used by fowlers and hunters, and the balls placed on the fire, the steam rushing from them will make such a horrible noise, that it will astonish any person who is ignorant of the contrivance. _The Talking Busts._ Procure two busts of plaster of Paris; place them on pedestals, on the opposite sides of the room. Let a thin tube, of an inch diameter, pass from the ear of one head through the pedestal, under the floor, and go up to the mouth of the other; taking care that the end of the tube that is next the ear of the one head, be considerably larger than that end which comes to the mouth of the other. Now, when a person speaks quite low into the ear of one bust, the sound is reverberated through the length of the tube, and will be distinctly heard by any one placing his ear to the mouth of the other. It is not necessary that the tube should come to the lips of the bust. If there be two tubes, one going to the ear, and the other to the mouth of each head, two persons may converse together, by whispers, without the knowledge of any person who may stand in the middle of the room. _The Inanimate Oracle._ Place a bust on a pedestal in the corner of a room, and let there be two tubes, as in the preceding article, one to go from the mouth, and the other from the ear, through the pedestal and the floor to an under apartment; there may be also wires, that go from the under jaw and the eyes of the bust, by which they may be easily moved. A person being placed in the room underneath, and applying his ear to one of the tubes at a signal given, will hear any question asked, and can immediately reply, by applying his mouth to the tube which communicates below, at the same time moving the eyes by the wire, to accompany his speech. _The Solar Concerto._ In a large case, similar to what is used for dials and spring clocks, the front of which, or at least the lower part, must be of glass, covered on the inside with gauze, place a barrel organ, which when wound up is prevented from playing by a catch that takes a toothed wheel at the end of the barrel. To one end of this catch join a wire, at the end of which is a flat circle of cork, of the same dimensions with the inside of a glass tube, in which it is to rise and fall. This tube must communicate with a reservoir that goes across the front part of the bottom of the case, which is to be filled with spirits, such as is used in thermometers. This case being placed in the sun, the spirits will be rarefied by the heat, and, rising in the tube, will lift up the catch or trigger, and set the organ in play; which will continue as long as it is kept in the sun; for the spirits cannot run out of the tube, that part of the catch to which the circle is fixed being prevented from rising beyond a certain point, by a check placed over it. Care must be taken to remove the machine out of the sun before the organ runs down, that its stopping may be evidently affected by the cold. In winter it will perform when placed before the fire. CURIOUS EXPERIMENTS WITH THE MAGIC LANTERN. The construction of this amusing optical machine is so well known, that to describe it would be superfluous; particularly as it can now be purchased at a very reasonable expense, at any of the opticians': but as many persons who have a taste for drawing might not be pleased with the designs to be had at the shops, or might wish to indulge their fancy in a variety of objects, which to purchase would become expensive, we here present our readers, in the first place, with the method of drawing them, which will be succeeded by a plain description of some very diverting experiments. _Of Painting the Glasses._ You first draw on a paper, the size of the glass, the subject you mean to paint; fasten this at each end of the glass with paste, or any other cement, to prevent it from slipping. Then with some very black paint mixed with varnish, draw with a fine camels'-hair pencil, very lightly, the outlines sketched on the paper, which, of course, are reflected through the glass. Some persons affirm that those outlines can be more readily traced with japan writing ink, and a common pen with a fine nib; but this, even if it succeeds in making a delicate black outline, is sure to be effaced by damp or wet. It would improve the natural resemblance, if the outlines were drawn with a strong tint of each of the natural colours of the object; but in this respect you may please your own fancy. When the outlines are dry, colour and shade your figures; but observe, to temper your colours with strong white varnish. A pleasing effect will be produced, if you leave strong lights in some parts of the drapery, &c., without any colours. The best colours for this purpose are transparent ones; opaque or mineral colours will not do. The following are in most repute. For Pink and crimson Lake or carmine. Blue Prussian blue. Green Calcined verdigris, or distilled ditto. Yellow Gamboge. _To represent a Storm at Sea._ Provide two strips of glass, whose frames are thin enough to admit both strips freely into the groove of the lantern. On one of these glasses paint the appearance of the sea from a smooth calm to a violent storm. Let these representations run gradually into each other, as in Fig. 9, and you will of course observe, that the more natural and picturesque the painting is, the more natural and pleasing will be the reflection. [Illustration: Fig. 9.] [Illustration: Fig. 10.] On the other glass, Fig. 10, paint various vessels on the ocean, observing to let that end where the storm is, appear in a state of violent commotion, and the vessels as if raised on the waves in an unsettled position, with heavy clouds about them. You then pass the glasses slowly through the groove, and when you come to that part where the storm is supposed to begin, move them gently up and down, which will give the appearance of the sea and vessels being agitated; increase the motion till they come to the height of the storm. You will thus have a very natural representation of the sea and ships in a calm and storm; and as you gradually draw the glasses back, the tempest will subside, the sky appear clear, and the vessels glide gently over the waves. By the means of two or three glasses, you may also represent a battle on land, or a naval engagement, with a variety of other pleasing experiments. _To produce the appearance of a Spectre on a Pedestal in the middle of a Table._ Enclose a small magic lantern in a box, Fig. 11, large enough to contain a small swing dressing-glass, which will reflect the light thrown on it by the lantern in such a way, that it will pass out at the aperture made at the top of the box; which aperture should be oval, and of a size adapted to the cone of light to pass through it. There should be a flap with hinges, to cover the opening, that the inside of the box may not be seen. [Illustration: Fig. 11.] There must be holes in that part of the box which is over the lantern, to let the smoke out; and over this must be placed a chafing-dish of an oblong figure, large enough to hold several lighted coals. This chafing-dish, for the better carrying on the deception, may be enclosed in a painted tin box, about a foot high, with a hole at top, and should stand on four feet, to let the smoke from the lantern escape. There must also be a glass planned to rise up and down in the groove _a b_, and so managed by a cord and pulley, _c d e f_, that it may be raised up and let down by the cord coming through the outside of the box. On this glass, the spectre, (or any other figure you please,) must be painted in a contracted or equal form, as the figure will reflect a greater length than it is drawn. When you have lighted the lamp in the lantern, and placed the mirror in a proper direction, put the box on a table, and, setting the chafing-dish in it, throw some incense, in powder, on the coals. You then open the trap door and let down the glass in the groove slowly, and when you perceive the smoke diminish, draw up the glass, that the figure may disappear, and shut the trap door. This exhibition will afford a deal of wonder; but observe, that all the lights in the room must be extinguished; and the box should be placed on a high table, that the aperture through which the light comes out may not be seen. There are many other pleasing experiments which may be made with the magic lantern, but the limits of our work will not permit us to specify them, without excluding many other equally interesting subjects of a different nature. _The Artificial Landscape._ Procure a box, as in Fig. 12, of about a foot long, eight inches wide, and six inches high, or any other dimensions you please, so they do not greatly vary from these proportions. At each of its opposite ends, on the inside of this box, place a piece of looking-glass that shall exactly fit: but at that end where the sight hole A is, scrape the quicksilver off the glass, through which the eye can view the objects. [Illustration: Fig. 12.] Cover the box with gauze, over which place a piece of transparent glass, which is to be well fastened in. Let there be two grooves at each of the places C D E F, to receive two printed scenes, as follow: On two pieces of pasteboard, let there be skilfully painted, on both sides, any subject you think proper, as woods, bowers, gardens, houses, &c.; and on two other boards, the same subjects on one side only, and cut out all the white parts: observe also, that there ought to be in one of them some object relative to the subject, placed at A, that the mirror placed at B may not reflect the hole on the opposite side. The boards painted on both sides are to slide in the grooves C D E F, and those painted on one side are to be placed against the opposite mirrors A and B; then cover the box with its transparent top. This box should be placed in a strong light, to have a good effect. When it is viewed through the sight hole, it will present an unlimited prospect of rural scenery, gradually losing itself in obscurity; and be found well worth the pains bestowed on its construction. _To draw, easily and correctly, a Landscape, or any other Object, without being obliged to observe the Rules of Perspective, and without the Aid of the Camera Obscura._ [Illustration: Fig. 13.] Procure a box of pasteboard, A B C D, Fig. 13, of about a foot and a half long, and made in the shape of a truncated pyramid, whose base, B D F G, is eight inches wide, and six inches high. Fix to the other end of it a tube of four or five inches long, and which you can draw out from the box more or less. Line the inside of the box with black paper, and place it on a leg or stand of wood, H, and on which it may be elevated or depressed by the hinge I. Take a small frame of wood, and divide it at every inch by lines of black silk drawn across it, forming forty-eight equal parts; divide these into still smaller equal parts, by lines of finer silk:[C] fix this frame at the end of B D, as the base of the pyramid. Provide a drawing-paper, divided into the same number of parts as in the frame, by lines, lightly drawn in pencil. It is not material of what size these divisions are; that will depend entirely on the size you propose to draw the objects by this instrument. Place this instrument opposite a landscape, or any other object that you want to draw, and fix the leg firmly on, or in the ground, that it may not shake; then turning it to the side you choose, raise or incline it, and put the tube further in or out, till you have gained an advantageous view of the object you intend to draw. Place your eye, E, by the instrument, which you have adjusted to the height of your eye, and, looking through the tube, carefully observe all that is contained in each division of the frame, and transpose it to the corresponding division in your paper; and if you have the least knowledge in painting or even drawing, you will make a very pleasing picture, and one in which all the objects will appear in the most exact proportion. By the same method you may draw all sorts of objects, as architecture, views, &c., and even human figures, if they remain some time in the same attitude, and are at a proper distance from the instrument. [C] The different thicknesses of the silk serve to distinguish more readily the corresponding divisions. _Illuminated Prospects._ Provide yourself with some of those prints that are commonly used in optical machines, printed on very thin white paper; taking care to make choice of such as have the greatest effect from the manner in which the objects are placed in perspective. Place one of these on the borders of a frame, and paint it carefully with the most lively colours, making use of none that are terrestrial. Observe to retouch those parts several times where the engraving is strongest,[D] then cut off the upper part or sky, and fix that on another frame. [Illustration: Fig. 14.] [Illustration: Fig. 15.] The prints being thus prepared, place them in a box, A B C D, Figs. 14 and 15, the opening to which, E F G H, should be a little less than the print. Cover this opening with a glass, and paint all the space between that and the prints, which should be about two or three inches, black. The frame that contains the sky should be about an inch behind the other. In the back part of this box, which is behind the prints, and which may be about four inches deep, place four or five small candlesticks to hold wax lights, and cover that part entirely with tin, that it may be the more luminous. When the print is placed between the wax lights and the opening in the front of the box, and there is no other light in the room, the effect will be highly pleasing; especially if the lights are at a sufficient distance from each other, and not too strong, that they may not occasion any blots in the print. Those prints that represent the rising or setting of the sun will have a very picturesque appearance. Such as represent conflagrations have also a striking effect. There should be two grooves for the print next the glass, that you may insert a second subject before you draw away the first; and that the lights in the back of the box may not be discovered. You must not, thinking to make the print more transparent, cover it with varnish; for that will prevent the gradation of the colours from being visible. The frame should enter the side of the box by a groove, that a variety of subjects may be introduced. [D] When you colour a print, place it before you, against a piece of glass, in a position nearly erect, that it may be enlightened by the sun. You may also colour both sides of the print. EXPERIMENTS IN MAGNETISM. _The Magnetic Wand._ Bore a hole three-tenths of an inch in diameter, through a round stick of wood; or get a hollow cane about eight inches long, and half an inch thick. Provide a small steel rod, and let it be very strongly impregnated with a good magnet: this rod is to be put in the hole you have bored through the wand, and closed at each end by two small ends of ivory that screw on, different in their shapes, that you may better distinguish the poles of the magnetic bar. When you present the north pole of this wand to the south[E] pole of a magnetic needle, suspended on a pivot, or to a light body swimming on the surface of the water, (in which you have placed a magnetic bar,) that body will approach the wand, and present that end which contains the south end of the bar: but if you present the north or south end of the wand to the north or south end of the needle, it will recede from it. [E] For the more clearly explaining this, it is to be observed, that the two ends of a magnet are called its poles. When placed on a pivot, in just equilibrium, that end which turns to the north is called the north pole, and the other end the south pole. _The Mysterious Watch._ You desire any person to lend you his watch, and ask him if it will go when laid on the table. He will, no doubt, say it will; in which case, you place it over the end of the magnet, and it will presently stop. You then mark the precise spot where you placed the watch, and, moving the point of the magnet, you give the watch to another person, and desire him to make the experiment; in which he not succeeding, you give it to a third (at the same time replacing the magnet) and he will immediately perform it. This experiment cannot be effected, unless you use a very strongly impregnated magnetic bar, (which may be purchased at the opticians',) and the balance of the watch must be of steel, which may be easily ascertained by previously opening it, and looking at the works. _The Magnetic Dial._ Procure a circle of wood or ivory, about 5 or 6 inches diameter, which must turn quite free on a stand with a circular border; on the ivory or wood circle fix a pasteboard, on which you place, in proper divisions, the hours, as on a dial. There must be a small groove in the circular frame, to receive the pasteboard circle; and observe, that the dial must be made to turn so free, that it may go round without moving the circular border in which it is placed. Between the pasteboard circle and the bottom of the frame, place a small artificial magnet, that has a hole in its middle. On the outside of the frame, place a small pin, which serves to show when the magnetic needle is to stop. This needle must turn quite free on its pivot, and its two sides should be in exact equilibrium. Then provide a small bag, with five or six divisions, like a lady's work-bag, but smaller. In one of these divisions put small square pieces of pasteboard, on which are written the numbers from 1 to 12. In each of the other divisions put twelve or more similar pieces, observing that all the pieces in each division must be marked with the same number. The needle being placed upon its pivot, and turned quickly about, it will necessarily stop at that point where the north end of the magnetic bar is placed, and which you previously know, by the situation of the small pin in the circular border. You then present to any person that division of the bag which contains the several pieces on which is written the number opposite to the north end of the bar, and tell him to draw any one he pleases. Then placing the needle on the pivot, you turn it quickly about, and it must necessarily stop at that particular number. _The Magnetic Cards._ Draw a pasteboard circle; you then provide yourself with two needles, similar to those used in the foregoing experiment, (which you must distinguish by some private mark,) with their opposite points touched with the magnet. When you place that needle whose pointed end is touched, on the pivot described in the centre of the circle, it will stop on one of the four pips, against which you have placed the pin in the frame; then take the needle off, and, placing the other, it will stop on the opposite point. Having matters thus arranged, desire a person to draw a card from a piquet pack, offering that card against which you have placed the pin of the dial, which you may easily do, by having a card a little longer than the rest. If he should not draw it the first time, as he probably may not, you must make some excuse for shuffling them again, such as letting the cards fall, as if by accident, or some other manoeuvre, until he fix on the card. You then tell him to keep it close, and not let it be seen. Then give him one of the two needles, and desire him to place it on the pivot, and turn it round, when it will stop at the colour of the card he chose; then taking that needle off, and exchanging it, unperceived, for the other, give it to a second person, telling him to do the same, and it will stop at the name of the identical card the first person chose. _The Magnetic Orrery._ Construct a round box, Fig. 16, about eight inches diameter, and half an inch deep. On the bottom fix a circular pasteboard drawn like the figure. You are likewise to have another pasteboard, drawn exactly the same, which must turn freely in the box, by means of an axis placed on a pivot, one end of which is to be fixed in the centre of the circle. On each of the seven smaller circles on the pasteboard, which you have fixed at the bottom of the box, place a magnetic bar, two inches long, in the same direction with the diameters of those circles, and their poles, in the situations expressed in the figure. There must be an index like the hour hand of a dial, fixed on the axis of the central circle, by which the pasteboard circle in the box may be turned about; also a needle (forming in the figure the other hand) that will turn freely on the axis, without moving the circular pasteboard. In each of the places where the word _question_ is, write a different question; and in each of the seven circles where the planetary signs are, write two answers to each question; observing, that there must only be seven words in each question: for instance, In division No. 1, of the circle G, which stands opposite question No. 1, write the first word of the first answer. In the division No. 2, of the next circle, write the second word; and so on to the last, which will be in the seventh division of the seventh circle. [Illustration: Fig. 16.] In the eighth division of the first circle, write the first word of the second answer; in the ninth, the second word of the same answer; and so on to the fourteenth division of the seventh circle, which must contain the last word of that answer. The same must be done for all the seven questions, and to each of these must be assigned two answers, the words of which are to be dispersed through the seven circles. At the centre of each of these circles place a pivot, and have two sets of magnetic needles like the hands of a watch, the pointed end of one set being north, and the other south. Now, the index of the central circle being directed to any one of the questions, if you place one of the two magnetic needles on each of the seven lesser circles, they will fix themselves according to the directions of the bars on the corresponding circles at the bottom of the box, and consequently point to the seven words that compose the answer. If you place one of the other needles on each circle, it will point to the words that are diametrically opposite to those of the first answer, the north pole being in the place of the south pole of the other. You therefore present this orrery to any person, and desire him to choose one of the questions there written. You then set the index of the central circle to that question; and, putting one of the needles on each of the seven circles, you turn it about, and when they all settle, the seven words they point to compose the answer. The moveable needle, whose point in the figure stands at September, is to place against the names of the months; and when the party has fixed upon a question, you place that needle against the month in which he was born, which will make the ceremony appear a sort of magic divination. The planetary signs are merely intended to aid this deception, and give it the appearance of astrology. _The Magic Verse._ The eight words which compose this Latin verse, "_Tot sunt tibi dote, quot coeli sidera, virgo,_"[F] being privately placed in any one of the different combinations of which they are susceptible, and which are 40,320 in number, to tell the order in which they are placed. [F] "Thy charms, O, Virgin! are as numerous as the stars of heaven." Provide a box that shuts with hinges, and is eight inches long, three wide, and half an inch deep, Fig. 17. Have eight pieces of wood, about one-third of an inch thick, two inches long, and one and a half wide, which will therefore, when placed close together, exactly fill the box. In each of these pieces or tablets place a magnetic bar, with their poles, as is expressed in Fig. 18. The bars being covered over, write on each of the tablets, in the order they then stand, one of the words of the foregoing Latin verse. [Illustration: Fig. 17.] [Illustration: Fig. 18.] [Illustration: Fig. 19.] On a very thin board of the same dimensions with the box, draw the eight circles, Fig. 19, A B C D E F G H, whose centres should be exactly over those of the eight tablets in the box, when the board is placed upon it. Divide each of those circles into eight parts, as in the figure, and in each of those divisions write one of the words of the Latin verse, and in the precise order expressed in the plate, so that when the board is placed over the box, the eight touched needles placed at the centre of the circles may be regulated by the poles of the bars in the box, and consequently the word that the needle points to in the circle will be the same with that inscribed on the tablet. Cover the board with a glass, to prevent the needles from rising off their pivots, as is done in the sea-compass. Over the board place four plates of glass, I L M N, Fig. 17, which will give the machine the figure of a truncated pyramid, of eight inches high. Cover it with a glass, or rather a board, in which are placed two lenses, O, of eight inches focus, and distant from each other about half an inch. Line the four plates of glass that compose the sides with very thin paper, that will admit the light, and at the same time prevent the company from seeing the circles on the board. These preparations being made, you give the box to any one, and tell him to place the tablets, on which the words are written privately, in what position he thinks proper, then to close the box, and, if he please, to wrap it up in paper, seal it, and give it to you. Then placing the board with the pyramid upon it, you immediately tell him the order in which the tablets are placed, by reading the words to which the needles on the circles point. INTERESTING EXPERIMENTS WITH THE AIR-PUMP. We shall not occupy the time of our readers by describing the form and nature of the air-pump; since those persons whose circumstances will enable them to have it, can purchase it properly made at an optician's, at less expense, and with far less trouble, than they can construct, or cause it to be constructed, themselves. _Bottles broken by Air._ Take a square bottle of thin glass, and of any size. Apply it to the hole of the air-pump, and exhaust the air. The bottle will sustain the weight of the external air as long as it is able, but at length it will suddenly burst into very small particles, and with a loud explosion. An opposite effect will be produced, if the mouth of a bottle be sealed so close that no air can escape; then place it in the receiver, and exhaust the air from its surface. The air which is confined within the bottle, when the external air is drawn off, will act so powerfully as to break the bottle into pieces. _Glass broken by Air._ Lay a square of glass on the top of an open receiver, and exhaust the air. The weight of the external air will press on the glass, and smash it to atoms. _The Hand fixed by Air._ If a person hold his hand on an open receiver, and the air be exhausted, it will be fixed as if pressed by a weight of sixty pounds. _Water boiled by Air._ Take water made so warm that you can just bear your hand in it, but that has not been boiled; put it under the receiver, and exhaust the air. Bubbles of air will soon be seen to rise, at first very small, but presently become larger, and will be at last so great, and rise with such rapidity, as to give the water the appearance of boiling. This will continue till the air is let into the receiver, when it will instantly cease. _Aërial Bubbles._ Take a stone, or any heavy substance, and putting it in a large glass with water, place it in the receiver. The air being exhausted, the spring of that which is in the pores of the solid body, by expanding the particles, will make them rise on its surface in numberless globules, which resemble the pearly drops of dew on the tops of the grass. The effect ceases when the air is let into the receiver. _The floating Stone._ To a piece of cork tie a small stone that will just sink it; and, putting it in a vessel of water, place it under the receiver. Then exhausting the receiver, the bubbles of air will expand from its pores, and, adhering to its surface, will render it, together with the stone, lighter than water, and consequently they will rise to the surface, and float. _Withered Fruit restored._ Take a shrivelled apple, and, placing it under the receiver, exhaust the air. The apple will immediately be plumped up, and look as fresh as when first gathered: for this reason, that the pressure of the external air being taken off, the air in the apple extends it, so much indeed that it will sometimes burst. If the air be let into the receiver, the apple will be restored to its pristine shrivelled state. _Vegetable Air-Bubbles._ Put a small branch of the tree with its leaves, or part of a small plant, in a vessel of water, and, placing the vessel in the receiver, exhaust the air. When the pressure of the external air is taken off, the spring of that contained in the air-vessels of the plant, by expanding the particles, will make them rise from the orifices of all the vessels for a long time together, and produce a most beautiful appearance. _The Mercurial Wand._ Take a piece of stick, cut it even at each end with a penknife, and immerse it in a vessel of mercury. When the air is pumped out of the receiver, it will at the same time come out of the pores of the wood, through the mercury, as will be visible at each end of the stick. When the air is again let into the receiver, it falls on the surface of the mercury, and forces it into the pores of the wood, to possess the place of the air. When the rod is taken out, it will be found considerably heavier than before, and that it has changed its colour, being now all over of a bluish hue. If cut transversely, the quicksilver will be seen to glitter in every part of it. _The Magic Bell._ Fix a small bell to the wire that goes through the top of the receiver. If you shake the wire, the bell will ring while the air is in the receiver; but when the air is drawn off, the sound will by degrees become faint, till at last not the least noise can be heard. As you let the air in again, the sound returns. _Feathers heavier than Lead._ At one end of a fine balance, hang a piece of lead, and at the other as many feathers as will poise it; then place the balance in the receiver. As the air is exhausted, the feathers will appear to overweigh the lead, and when all the air is drawn off, the feathers will preponderate, and the lead ascend. _The self-moving Wheel._ Take a circle of tin, about ten inches in diameter, or of any other size that will go into the receiver, and to its circumference fix a number of tin vanes, each about an inch square. Let this wheel be placed between two upright pieces on an axis, whose extremities are quite small, so that the wheel may turn in a vertical position with the least possible force. Place the wheel and axis in the receiver, and exhaust the air. Let there be a small pipe with a cock; one end of the pipe to be outside the top of the receiver, and the other to come directly over the vanes of the wheel. When the air is exhausted, turn the cock, and a current will rush against the vanes of the wheel, and set it in motion, which will increase, till the receiver is filled with air. _The Artificial Halo._ Place a candle on one side of the receiver, and let the spectator place himself at a distance from the other side. Directly the air begins to be exhausted, the light of the candle will be refracted in circles of various colours. _The Mercurial Shower._ Cement a piece of wood into the lower part of the neck of an open receiver, and pour mercury over it. After a few strokes of the pump, the pressure of the air on the mercury will force it through the pores of the wood in the form of a beautiful shower. If you take care that the receiver is clear and free from spots or dust, and it is dry weather, it will appear like a fiery shower, when exhibited in a dark room. _Magic Fountain._ Take a tall glass tube, hermetically sealed both at top and bottom, by means of a brass cap screwed on to a stop-cock, and place it on the plate of the pump. When the air is exhausted, turn the cock, take the tube off the plate, and plunge it into a basin of mercury or water. Then the cock being again turned, the fluid, by the pressure of the air, will play upon the tube in the form of a beautiful fountain. _The Exploded Bladder._ Take a glass pipe open at both ends, to one of which tie fast a wet bladder, and let it dry. Then place it on the plate of the pump. While the air presses the bladder equally on both sides, it will lie even and straight; but as soon as the air is exhausted, it will press inwards, and be quite concave on the upper side. In proportion as the air is exhausted, the bladder will become more stretched; it will soon yield to the incumbent pressure, and burst with a loud explosion. To make this experiment more easy, one part of the bladder should be scraped with a knife, and some of its external fibres taken off. _The Cemented Bladder._ Tie the neck of the bladder to a stop-cock, which is to be screwed to the plate of the pump, and the air exhausted from the bladder; then turn the stop-cock, to prevent the re-entrance of the air, and unscrew the whole from the pump. The bladder will be transformed into two flat skins, so closely applied together, that the strongest man cannot raise them half an inch from each other; for an ordinary-sized bladder, of six inches across the widest part, will have one side pressed upon the other with a force equal to 396 pounds' weight. _Cork heavier than Lead._ Let a large piece of cork be pendent from one end of a balance beam, and a small piece of lead from the other; the lead should rather preponderate. If this apparatus be placed under a receiver on the pump, you will find that when the air is exhausted, the lead, which seemed the heaviest body, will ascend, and the cork outweigh the lead. Restore the air, and the effect will cease. This phenomenon is only on account of the difference of the size in the two objects. The lead, which owes its heaviness to the operation of the air, yields to a lighter because a larger substance when deprived of its assistance. _The animated Bacchus._ Construct a figure of Bacchus, seated on a cask; let his belly be formed by a bladder, and let a tube proceed from his mouth to the cask. Fill this tube with coloured water or wine, then place the whole under the receiver. Exhaust the air, and the liquor will be thrown up into his mouth. While he is drinking, his belly will expand. _The Artificial Balloon._ Take a bladder containing only a small quantity of air, and a piece of lead to it, sufficient to sink it, if immersed in water. Put this apparatus into a jar of water, and place the whole under a receiver. Then exhaust the air, and the bladder will expand, become a balloon lighter than the fluid in which it floats, and ascend, carrying the weight with it. _Curious Experiments with a Viper._ Many natural philosophers, in their eagerness to display the powers of science, have overlooked one of the first duties of life, humanity; and, with this view, have tortured and killed many harmless animals, to exemplify the amazing effects of the air-pump. We, however, will not stain the pages of this little work by recommending any such species of cruelty, which in many instances can merely gratify curiosity; but as our readers might like to read the effect on animals, we extract from the learned Boyle an account of his experiment with a viper. He took a newly-caught viper, and, shutting it up in a small receiver, extracted the air. At first, upon the air being drawn away, the viper began to swell; a short time after it gasped and opened its jaws; it then resumed its former lankness, and began to move up and down within the receiver, as if to seek for air. After a while, it foamed a little, leaving the foam sticking to the inside of the glass; soon after, the body and neck became prodigiously swelled, and a blister appeared on its back. Within an hour and a half from the time the receiver was exhausted, the distended viper moved, being yet alive, though its jaws remained quite stretched; its black tongue reached beyond the mouth, which had also become black in the inside: in this situation it continued for three hours; but on the air being re-admitted, the viper's mouth was presently closed, and soon after opened again; and these motions continued some time, as if there were still some remains of life. It is thus with animals of every kind; even minute microscopical insects cannot live without air. _Experiments with Sparrows._ Count Morozzo placed successively several full-grown sparrows under a glass receiver, inverted over water. It was filled with atmospheric air, and afterwards with vital air. He found, First.--That in _atmospheric_ air, HOURS MIN. The first sparrow lived 3 0 The second sparrow lived 0 3 The third sparrow lived 0 1 The water rose in the vessels eight lines during the life of the first; four during the life of the second; and the third produced no absorption. Second.--In _vital_ air or _oxygen_, HOURS MIN. The first sparrow lived 5 23 The second 2 10 The third 1 30 The fourth 1 10 The fifth 0 30 The sixth 0 47 The seventh 0 27 The eighth 0 30 The ninth 0 22 The tenth 0 21 The above experiments elicit the following conclusions:--1. That an animal will live longer in vital than in atmospheric air.--2. That one animal can live in air, in which another has died.--3. That, independently of air, some respect must be had to the constitution of the animal; for the sixth lived 47 minutes, the fifth only thirty.--4. That there is either an absorption of air, or the production of a new kind of air, which is absorbed by the water as it rises. AMUSING EXPERIMENTS IN ELECTRICITY. _The Animated Feather._ Electrify a smooth glass tube with a rubber, and hold a small feather at a short distance from it. The feather will instantly fly to the tube, and adhere to it for a short time; it will then fly off, and the tube can never be brought close to the feather till it has touched the side of the room, or some other body that communicates with the ground. If, therefore, you take care to keep the tube between the feather and the side of the room, you may drive it round to all parts of the room without touching it; and, what is very remarkable, the same side of the feather will be constantly opposite the tube. While the feather is flying before the smooth tube, it will be immediately attracted by an excited rough tube or a stick of wax, and fly continually from one tube to the other, till the electricity of both is discharged. _The Candle lighted by Electricity._ Charge a small coated phial, whose knob is bent outwards so as to hang a little over the body of the phial; then wrap some loose cotton over the extremity of a long brass pin or wire, so as to stick moderately fast to its substance. Next roll this extremity of the pin, which is wrapped up in cotton, in some fine powdered resin; then apply the extremity of the pin or wire to the external coating of the charged phial, and bring, as quickly as possible, the other extremity, that is wrapped round with cotton, to the knob; the powdered resin takes fire, and communicates its flame to the cotton, and both together burn long enough to light a candle. Dipping the cotton in oil of turpentine will do as well, if you use a larger sized jar. _Candle Bombs._ Procure some small glass bubbles, having a neck about an inch long, with very slender bores, by means of which a small quantity of water is to be introduced into them, and the orifice afterwards closed up. This stalk being put through the wick of a burning candle, the flame boils the water into a steam, and the glass is broken with a loud explosion. _The Artificial Spider._ Cut a piece of burnt cork, about the size of a pea, into the shape of a spider; make its legs of linen thread, and put a grain or two of lead in it to give it more weight. Suspend it by a fine line of silk between an electrified arch and an excited stick of wax; and it will jump continually from one body to the other, moving its legs at the same time, as if animated, to the great surprise of the unconscious spectator. _The Miraculous Portrait._ Get a large print (suppose of the king) with a frame and glass. Cut the print out at about two inches from the frame all round; then with thin paste fix the border that is left on the inside of the glass, pressing it smooth and close; fill up the vacancy, by covering the glass well with leaf-gold or thin tin-foil, so that it may lie close. Cover likewise the inner edge of the bottom part of the back of the frame with the same tin-foil, and make a communication between that and the tin-foil in the middle of the glass; then put in the board, and that side is finished. Next turn up the glass, and cover the fore-side with tin-foil, exactly over that on the back part; and when it is dry, paste over it the panel of the print that was cut out, observing to bring the corresponding parts of the border and panel together, so that the picture will appear as at first, only part of it behind the glass, and part before. Lastly, hold the print horizontally by the top, and place a little moveable gilt crown on the king's head. Now, if the tin-foil on both sides of the glass be moderately electrified, and another person take hold of the bottom of the frame with one hand, so that his fingers touch the tin-foil, and with the other hand attempt to take off the crown, he will receive a very smart blow, and fail in the attempt. The operator, who holds the frame by the upper end, where there is no tin-foil, feels nothing of the shock, and can touch the face of the king without danger, which he pretends is a test of his loyalty. _The Cup of Tantalus._ You place a cup of any sort of metal on a stool of baked wood or a cake of wax. Fill it to the brim with any liquor; let it communicate with the branch by a small chain; and when it is moderately electrified, desire a person to taste the liquor, without touching the cup with his hands, and he will instantly receive a shock on his lips. The motion of the wheel being stopped, you taste the liquor yourself, and desire the rest of the company to do so; you then give your operator (who is concealed in an adjoining room) the signal, and he again charges the cup; you desire the same person to taste the liquor a second time, and he will receive a second shock. _Magical Explosion._ Make up some gunpowder, in the form of a small cartridge, in each end of which put a blunt wire, so that the ends inside of the cartridge be about half an inch off each other; then join the chain that proceeds from one side of the electrifying battery, to the wire at the other end, the shock will instantly pass through the powder, and set it on fire. _Artificial Earthquake._ In the middle of a large basin of water, lay a round wet board. On the board place any kind of building, made of pasteboard, of separate pieces, and not fastened together. Then, fixing a wire that communicates with the two chains of the electrifying battery, so that it may pass over the board and the surface of the water, upon making the explosion, the water will become agitated as in an earthquake, and the board, moving up and down, will overturn the structure, while the cause of the commotion is totally concealed. _The Magic Dance._ From the middle of the brass arch suspend three small bells. The two outer bells hang by chains, and the middle one by a silk string, while a chain connects it with the floor. Two small knobs of brass, which serve as clappers, hang by silk strings, one between each two bells. Therefore, when the two outer bells communicating with the conductor are electrified, they will attract the clappers and be struck by them. The clappers being thus loaded with electricity, will be repelled, and fly to discharge themselves upon the middle bell, after which they will be again attracted by the outer bells; and thus, by striking the bells alternately, the ringing may be continued as long as the operator pleases. You next suspend a plate of metal from the same part of the arch to which the bells are connected; then, at the distance of a few inches from the arch, and exactly under it, place a metal stand _of the same size_. On the stand place several figures of men, animals, or what you please, cut in paper, and pretty sharply pointed at each extremity. When the plate that hangs from the arch is electrified, the figures will dance with astonishing rapidity, and the bells will keep ringing, to the no small entertainment of the spectators. _The Electrical Fountain._ Suspend a vessel of water from the middle of the brass arch, and place in the vessel a small tube. The water will be one continued stream; and if the electrification be strong, a number of streams will issue, in form of a cone, the top of which will be at the extremity of the tube. This experiment may be stopped and renewed almost instantly, as if at the word of command. _The Electric Kite._ Make a small cross of two light strips of cedar, the arms so long as to reach to the four corners of a large thin silk handkerchief, when extended; tie the corners of the handkerchief to the extremities of the cross; and you have the body of the kite, which being properly accommodated with a tail, loop, and string, will rise in the air like those made of paper; but this being silk, it is more adapted to bear the wet and wind of a thunder gust, without tearing. To the top of the upright stick of the cross is to be fixed a very sharp-pointed wire, rising a foot or more above the wood. To the end of the twine is to be tied a silk ribbon, and where the silk and twine join, a key may be fastened. This kite is to be raised when a thunder-storm appears to be coming on; and the person who holds the string must stand within a door or window, or under some cover, so that the silk ribbon may not be wet; and care must be taken that the twine do not touch the frame of the door or window. As soon as any of the thunder clouds come over the kite, the pointed wire will draw the electric fire from them, and the kite, with all the twine, will be electrified, while the loose filaments of the twine will stand out every way, and be attracted by an approaching finger. When the rain has wetted the kite and twine, so that it can conduct the electric fire freely, you will find it stream out plentifully from the key, on the approach of your knuckle. At this key an electric phial may be charged; and from electric fire thus obtained, spirits may be kindled, and all the other electric experiments performed which are usually done by the help of a rubbed glass or tube; and thereby the identity of the electric matter with that of lightning completely demonstrated. _The Magic Chase._ On the top of a finely-pointed wire, rising perpendicularly from the conductor, let another wire, sharpened at each end, be made to move freely, as on a centre. If it be well balanced, and the points bent horizontally, in opposite directions, it will, when electrified, turn very swiftly round, by the re-action of the air against the current which flows from off the points. These points may be nearly concealed, and the figures of men and horses, with hounds, and a hare, stag, or fox, may be placed upon the wires, so as to turn round with them, when they appear as if in pursuit. The chase may be diversified, and a greater variety of figures upon them, by increasing the number of wires proceeding from the same centre. _The Unconscious Incendiary._ Let a person stand upon a stool made of baked wood, or upon a cake of wax, and hold a chain which communicates with the branch. On turning the wheel he will become electrified; his whole body forming part of the prime conductor; and he will emit sparks whenever he is touched by a person standing on the floor. If the electrified person put his finger, or a rod of iron, into a dish containing warm spirits of wine, it will be immediately in a blaze; and if there be a wick or thread in the spirit, that communicates with a train of gunpowder, he may be made to blow up a magazine, or set a city on fire, with a piece of cold iron, and at the same time be ignorant of the mischief he is doing. _The Inconceivable Shock._ Put in a person's hand a wire that is fixed on to the hook that comes from the chain, which communicates with one side of the battery, and in his other hand put a small wire with a hook at the end of it, which you direct him to fix on to a hook which comes from the other chain. On attempting to do this, he will instantly receive a shock from his body, without being able to guess the cause. Care should be taken that the shock be not too strong; and regard should be had to the constitution and disposition of the party, as a shock that would hardly affect one person, might be productive of very serious consequences to another. Much entertainment may be derived from concealing the chain that communicates with that which proceeds from the outside of the battery, under a carpet, and placing the wire that communicates with the chain from the inside, in such a manner that a person may put his hand on it without suspicion, at the same time that his feet are upon the other wire. The whole company may be made to partake of the shock, by joining hands, and forming a circle. The experiment may also be varied if they tread upon each other's toes, or lay their hands upon each other's heads. It might happen, by the latter method, that the whole company would be struck to the ground; but it will be productive of no danger, and very little inconvenience; on the contrary, it has happened that they have neither heard nor felt the shock. * * * * * To exhibit the five following amusements in electricity, the room in which they are performed must be darkened. _The Miraculous Luminaries._ You must previously prepare the following phosphorus: Calcine common oyster-shells, by burning them in the fire for half an hour; then reduce them to powder; of the clearest of which take three parts, and of flowers of sulphur one part; put the mixture into a crucible, about an inch and a half deep. Let it burn in a strong fire for rather better than an hour; and when it is cool, turn it out and break it in pieces; and, taking those pieces into a dark place, scrape off the parts that shine brightest, which, if good, will be a white powder. Then construct a circular board, of three or four feet diameter, on the centre of which draw in gum-water, or any adhesive liquid, a half-moon, of three or four inches diameter, and a number of stars round it, at different distances, and of various magnitudes. Strew the phosphorus over the figures, to the thickness of about a quarter of an inch, laying one coat over the other. Place this board behind a curtain; and when you draw the curtain up or back, discharge one electrifying jar or phial over each figure, at the distance of about an inch, and they will become illuminated, exhibiting a very striking resemblance of the moon and stars; and will continue to shine for about half an hour, their splendour becoming gradually more faint. _The Fiery Shower._ On the plate put a number of any kind of seeds, grains of sand, or brass dust. The conductor being strongly electrified, those light particles will be attracted and repelled by the plate suspended from the conductor, with amazing rapidity, so as to exhibit a perfect fiery shower. Another way is by a sponge that has been soaked in water. When this sponge is first hung to the conductor, the water will drop from it very slowly; but when it is electrified, the drops will fall very fast, and appear like small globes of fire, illuminating the basin into which they fall. _The Illuminated Vacuum._ Take a tall receiver that is very dry, and fix through the top of it, with cement, a blunt wire; then exhaust the receiver, and present the knob of the wire to the conductor, and every spark will pass through the vacuum in a broad stream of light, visible through the whole length of the receiver, let it be as tall as it will. This generally divides into a variety of beautiful rivulets, which are continually changing their course, uniting and dividing again in the most pleasing manner. If a jar be discharged through this vacuum, it presents the appearance of a very dense body of fire, darting directly through the centre of the vacuum, without touching the sides; whereas, when a single spark passes through, it generally goes more or less to the side, and a finger placed on the outside of the glass will draw it wherever a person pleases. If the vessel be grasped by both hands, every spark is felt like the pulsation of a large artery; and all the fire makes towards the hands. This pulsation is even felt at some distance from the receiver, and a light is seen between the hand and the glass. All this while, the pointed wire is supposed to be electrified positively; if it be electrified negatively, the appearance is astonishingly different; instead of streams of fire, nothing is seen but one uniform luminous appearance, like a white cloud, or the _milky way_ in a clear star-light night. It seldom reaches the whole length of the vessel, but generally appears only at the end of the wire, like a lucid ball. If a small phial be inserted in the neck of a small receiver, so that the external surface of the glass be exposed to the vacuum, it will produce a very beautiful appearance. The phial must be coated on the inside; and while it is charging, at every spark taken from the conductor into the inside, a flash of light is seen to dart at the same time from every part of the external surface of the phial, so as to quite fill the receiver. Upon making the discharge, the light is seen to run in a much closer body, the whole coming out at once. _The Illuminated Cylinder._ Provide a glass cylinder, three feet long, and three inches diameter; near the bottom of it fix a brass plate, and have another brass plate, so contrived that you may let it down the cylinder, and bring it as near the first plate as you desire. Let this cylinder be exhausted and insulated, and when the upper part is electrified, the electric matter will pass from one plate to the other, when they are at the greatest distance from each other that the cylinder will admit. The brass plate at the bottom of the cylinder will also be as strongly electrified as if it were connected by a wire to the prime conductor. The electric matter, as it passes through this vacuum, presents a most brilliant spectacle, exhibiting sparkling flashes of fire the whole length of the tube, and of a bright silver hue, representing the most lively exhalations of the aurora borealis. _The Electric Aurora Borealis._ Make a Torricellian vacuum[G] in a glass tube, about three feet long, and hermetically sealed.[H] Let one end of this tube be held in the hand, and the other applied to the conductor; and immediately the whole tube will be illuminated from one end; and when taken from the conductor will continue luminous, without interruption, for a considerable time, very often about a quarter of an hour. If, after this, it be drawn through the hand either way, the light will be uncommonly brilliant, and, without the least interruption, from one end to the other, even to its whole length. After this operation, which discharges it in a great measure, it will still flash at intervals, though it be held only at the extremity, and quite still; but if it be grasped by the other hand at the same time, in a different place, strong flashes of light will dart from one end to the other. This will continue for twenty-four hours, and often longer, without any fresh excitation. Small and long glass tubes, exhausted of air, and bent in many irregular crooks and angles, will, when properly electrified, exhibit a very beautiful representation of vivid flashes of lightning. [G] A Torricellian vacuum is made by filling a tube with pure mercury and then inverting it, in the same manner as in making a barometer; for as the mercury runs out, all the space above will be a true vacuum. [H] A glass is hermetically sealed by holding the end of it in the flame of a candle, till it begin to melt, and then twisting it together with a pair of pincers. _The Electrical Orrery._ By the motion of circulating points, we may in some measure imitate the revolutions of the heavenly bodies, forming what is called the _Electrical Orrery_. Let a single wire, with the extremities pointed and turned, be nicely balanced on a point; fix a small glass ball over its centre to represent the sun. At one extremity of the wire, let a small wire be soldered perpendicularly, and on this balance another small wire with its ends pointed and turned, and having a small pith ball in its centre, to represent the earth, and a smaller ball of the same kind at one of the angles, for the moon. Let the whole be supported upon a glass pillar, and be conducted by a chain proceeding from the prime conductor to the wire supporting the glass ball. Now, when the machine is put in motion, the wires will turn round, so that the ball representing the earth will move round the central ball, and the little ball at the angle of the smaller wire will at the same time revolve about the earth. _The Electrified Cotton._ Take a small lock of cotton, extended in every direction as much as can conveniently be done, and by a linen thread about five or six inches long, or by a thread drawn out of the same cotton, tie it to the end of the prime conductor; then set the machine in motion, and the lock of cotton, on being electrified, will immediately swell, by repelling its filaments from one another, and will stretch itself towards the nearest conductor. In this situation let the cylinder be kept in motion, and present the end of your finger, or the knob of a wire, towards the lock of cotton, which will then immediately move towards the finger, and endeavour to touch it; but take with the other hand a pointed needle, and present its point towards the cotton, a little above the end of the finger, and the cotton will be observed immediately to shrink upwards, and move towards the prime conductor. Remove the needle, and the cotton will come again towards the finger. Present the needle, and the cotton will shrink again. _The Electric Sparks._ When the prime conductor is situated in its proper place, and electrified by whirling the cylinder, if a metallic wire, with a ball at its extremity, or the knuckle or a finger be presented to the prime conductor, a spark will be seen to issue between them, which will be more vivid, and will be attended with a greater or less explosion, according as the ball is larger. The strongest and most vivid sparks are drawn from that end or side of the prime conductor which is farthest from the cylinder. The sparks have the same appearance whether they be taken from the positive or negative conductor; they sometimes appear like a long line of fire reaching from the prime conductor to the opposed body, and often (particularly when the spark is long, and different conducting substances in the line of its direction) it will have the appearance of being bent to sharp angles in different places, exactly resembling a flash of lightning. The figure of a spark varies with the superficial dimensions of the part from which it is taken. If it be drawn from a ball of two or three inches in diameter, it will have the appearance of a straight line; but if the ball from which it is drawn be much smaller, as half an inch in diameter, it will assume the zig-zag appearance above mentioned. _Dancing Balls._ Take a common tumbler or glass jar, and having placed a brass ball in one of the holes of the prime conductor, set the machine in motion, and let the balls touch the inside of the tumbler; while the ball touches only one point, no more of the surface of the glass will be electrified, but by moving the tumblers about, so as to make the ball touch many points successively, all the points will be electrified, as will appear by turning down the tumbler over a number of pith or cork balls placed on a table. These balls will immediately begin to fly about. _The Leyden Phial._ When a nail or piece of thick brass wire, &c., is put into a small apothecary's phial, and electrified, remarkable effects follow; but the phial must be very dry or warm. Rub it once beforehand with your finger, on which put some pounded chalk. If a little mercury, or a few drops of spirit of wine, be put into it, the experiment succeeds the better. As soon as this phial and nail are removed from the electrifying glass, or the prime conductor, to which it has been exposed, is taken away, it throws out a stream of flame so long, that with this burning-machine in your hand, you may take about sixty steps in walking about your room. When it is electrified strongly, you may take it into another room, and there fire spirits of wine with it. If, while it is electrifying, you put your finger, or a piece of gold which you hold in your hand, to the nail, you receive a shock which stuns your arms and shoulders. A tin tube, or a man placed upon electrics, is electrified much stronger by these means than in the common way. When you present this phial and nail it to a tin tube, fifteen feet long, nothing but experience can make a person believe how strongly it is electrified. Two thin glasses have been broken by the shock of it. It appears extraordinary, that when this phial and nail are in contact with their conducting or non-conducting matter, the strong shock does not follow. _The Self-moving Wheel._ The self-moving wheel is made of a thin round plate of window-glass, seventeen inches in diameter, well gilt on both sides, to within two inches of the circumference. Two small hemispheres of wood are then fixed with cement, to the middle of the upper and under sides, centrally opposite, and in each of them a thick strong wire, eight or ten inches long, making together the axis of the wheel. It turns horizontally on a point at the lower end of its axis, which rests on a bit of brass, cemented within a glass salt-cellar. The upper end of its axis passes through a hole in a thin brass plate, cemented to a long and strong piece of glass, which keeps it six or eight inches distant from any non-electric, and has a small ball of wax or metal on its top. In a circle on the table which supports the wheel, are fixed twelve small pillars of glass, at about eleven inches distance, with a thimble on the top of each. On the edge of the wheel is a small leaden bullet, communicating by a wire with the upper surface of the wheel; and about six inches from it is another bullet, communicating, in like manner, with the under surface. When the wheel is to be charged by the upper surface, a communication must be made from the under surface with the table. When it is well charged it begins to move. The bullet nearest to a pillar moves towards the thimble on that pillar, and, passing by, electrifies it, and then pushes itself from it. The succeeding bullet, which communicates with the other surface of the glass, more strongly attracts that thimble, on account of its being electrified before by the other bullet; and thus the wheel increases its motion, till the resistance of the air regulates it. It will go half an hour, and make, one minute with another, twenty turns in a minute, which is six hundred turns in the whole, the bullet of the upper surface giving in each turn twelve sparks to the thimbles, which make seven thousand two hundred sparks, and the bullet of the under surface receiving as many from the thimble, these bullets moving in the time nearly two thousand five hundred feet. The thimbles should be well fixed, and in so exact a circle, that the bullets may pass within a very small distance of each of them. If instead of two bullets you put eight, four communicating with the upper surface, and four with the under surface, placed alternately, (which eight, at about six inches distance, complete the circumference,) the force and swiftness will be greatly increased, the wheel making fifty turns in a minute; but then it will not continue moving so long. _Resin ignited by Electricity._ Wrap some cotton wool, containing as much powdered resin as it will hold, about one of the knobs of a discharging-rod. Then having charged a Leyden jar, apply the naked knob of the rod to the external coating, and the knob enveloped by the cotton to the ball of the wire. The act of discharging the jar will set fire to the resin. A piece of phosphorus or camphor wrapped in cotton wool, and used in the same way, will be much more easily inflamed. _Spirits ignited by Electricity._ Hang a small ball with a stem to the prime conductor, so that the ball may project below the conductor. Then warm a little ardent spirit, by holding it a short time over a candle in a metallic spoon; hold the spoon about an inch below the ball, and set the machine in motion. A spark will soon issue from the ball and set fire to the spirits. This experiment may be varied different ways, and may be rendered very agreeable to a company of spectators. A person, for instance, standing upon an electric stool, and communicating with the prime conductor, may hold the spoon with the spirits in his hand, and another person, standing upon the floor, may set the spirits on fire, by bringing his finger within a small distance of it. Instead of his finger he may fire the spirits with a piece of ice, when the experiment will seem much more surprising. If the spoon be held by the person standing upon the floor, and the insulated person bring some conducting substance over the surface of the spirit, the experiment succeeds as well. _The Electric Balloon._ Two balloons, made of the allantoides of a calf, are to be filled with hydrogen gas, of which each contains about two cubic feet. To each of these is to be suspended, by a silken thread about eight feet long, such a weight as is just sufficient to prevent it from rising higher in the air; they are connected, the one with the positive, the other with the negative conductor, by small wires about 30 feet in length; and being kept nearly 20 feet asunder, are placed as far from the machine as the length of the wires will admit. On being electrified, these balloons will rise up in the air as high as the wire will allow, attracting each other, and uniting as it were into one cloud, gently descending. _The Illuminated Water._ Connect one end of a chain with the outside of a charged phial, and let the other end lie on the table. Place the end of another piece of chain at the distance of about a quarter of an inch from the former; and set a glass decanter of water on these separated ends. On making the discharge, the water will appear perfectly luminous. The electric spark may be rendered visible in water, in the following manner:--Take a glass tube of about half an inch in diameter, and six inches long; fill it with water, and to each extremity of the tube adapt a cork, which may confine the water; through each cork insert a blunt wire, so that the extremities of the wires within the tube may be very near one another; then, on connecting one of these wires with the coating of a small charged phial, and touching the other wire with the knob of it, the shock will pass through the wires, and cause a vivid spark to appear within their extremities within the tube. The charge in this experiment must be very weak, or there will be danger of bursting the tube. _The Electrified Ball._ Place an ivory ball on the prime conductor of the machine, and take a strong spark, or send the charge of a Leyden phial through its centre, and the ball will appear perfectly luminous; but if the charge be not sent through the centre, it will pass over the surface of the ball and singe it. A spark made to pass through a ball of box-wood, not only illuminates the whole, but makes it appear of a beautiful crimson, or rather a fine scarlet colour. _Illuminated Phosphorus._ Put some of Canton's phosphorus into a clear glass phial, and stop it with a glass stopper, or a cork and sealing-wax. If this wire be kept in a darkened room (which for this experiment must be very dark) it will give no light; but let two or three strong sparks be drawn from the prime conductor, when the phial is kept about two inches distant from the sparks, so that it may be exposed to that light, and this phial will receive the light and afterwards will appear illuminated for a considerable time. This powder may be stuck upon a board by means of the white of an egg, so as to represent figures of planets, letters, or any thing else, at the pleasure of the operator, and these figures may be illuminated in the dark, in the same manner as the above described phial. A beautiful method of expressing geometrical figures with the above powder, is to bend small glass tubes, of about the tenth part of an inch diameter, in the shape of the figure desired, and then to fill them with the phosphoric powder. These may be illuminated in the manner described; and they are not so subject to be spoiled, as the figures represented upon the board frequently are. _The Luminous Writing._ Small pieces of tin-foil may be stuck on a flat piece of glass, so as to represent various fanciful figures. Upon the same principle is the word LIGHT produced, in luminous characters. It is formed by the small separations of the tin-foil pasted on a piece of glass fixed in a frame of baked wood. To use this, the frame must be held in the hand, and the ball presented to the conductor. The spark will then be exhibited in the intervals composing the word, from whence it passes to the hook, and thence to the ground by a chain. The brilliancy of this is equal to that of the spiral tubes. _The Electric Explosion._ Take a card, a quire of paper, or the cover of a book; and keep it close to the outside coating of a charged jar: put one knob of the discharging-rod upon the card, quire of paper, &c., so that, between the knob and coating of the jar, the thickness of that card or quire of paper only is interposed; lastly, by bringing the other knob of the discharged rod near the knob of the jar, make the discharge, and the electric spark will pierce a hole (or perhaps several) quite through the card or quire of paper. This hole has a bur raised on each side, except the card, &c., be pressed hard between the discharging-rod and the jar. If this experiment be made with two cards instead of one, which, however, must be kept very little distant from one another, each of the cards, after the explosion, will be found pierced with one or more holes, and each hole will have burs on both surfaces of each card. The hole, or holes, are larger or smaller, according as the card, &c., is more damp or more dry. It is remarkable, that if the nostrils are presented to it, they will be affected with a sulphurous, or rather a phosphoric smell, just like that produced by an excited electric. If, instead of paper, a very thin plate of glass, resin, sealing-wax, or the like, be interposed between the knob of the discharging-rod and the outside coating of the jar, on making the discharge, this will be broken in several pieces. _Electrified Air._ Fix two or three pointed needles into the prime conductor of an electrical machine, and set the glass in motion so as to keep the prime conductor electrified for several minutes. If now, an electometer be brought within the air that is contiguous to the prime conductor, it will exhibit signs of electricity, and this air will continue electrified for some time, even after the machine has been removed into another room. The air, in this case, is electrified positively; it maybe negatively electrified by fixing the needles in the negative conductor while insulated, and making a communication between the prime conductor and the table, by means of a chain or other conducting substance. The air of a room may be electrified in another way. Charge a large jar, and insulate it; then connect two or more sharp-pointed wires or needles, with the knob of the jar, and connect the outside coating of the jar with the table. If the jar be charged positively, the air of the room will soon become positively electrified likewise; but if the jar be charged negatively, the electricity communicated by it to the air will also become negative. A charged jar being held in one hand, and the flame of an insulated candle held in the other being brought near the knob of the jar, will also produce the same effect. _Another Electric Orrery._ (See page 92.) From the prime conductor of an electric machine suspend six concentric hoops of metal at different distances from each other, in such a manner as to represent in some measure the proportional distances of the planets. Under these, and at a distance of about half an inch, place a metallic plate, and upon this plate, within each of the hoops, a glass bubble blown very thin and light. On electrifying the hoops, the bubbles will be immediately attracted by them, and will continue to move round the hoops as long as the electrification continues. If the electricity be very strong, the bubbles will frequently be driven off, run hither and thither on the plate, making a variety of surprising motions round their axis; after which they will return to the hoop, and circulate as before; and if the room be darkened, they will all appear beautifully illuminated with electric light. _The Electric Ball._ Provide a ball of cork about three-quarters of an inch in diameter, hollowed out in the internal part by cutting it in two hemispheres, scooping out the inside, and then joining them together with paste. Having attached this to a silk thread between three and four feet in length, suspend it in such a manner that it may just touch the knob of an electric jar, the outside of which communicates with the ground. On the first contact it will be repelled to a considerable distance, and after making several vibrations, will remain stationary; but if a candle be placed at some distance behind it, so that the ball may be between it and the bottle, the ball will instantly begin to move, and will turn round the knob of the jar, moving in a kind of ellipsis as long as there is any electricity in the bottle. This experiment is very striking, though the motions are far from being regular; but it is remarkable that they always affect the elliptical rather than the circular form. _To spin Sealing-wax into Threads by Electricity._ Stick a small piece of sealing-wax on the end of a wire, and set fire to it. Then put an electrical machine in motion, and present the wax just blown out at the distance of some inches from the prime conductor. A number of extremely fine filaments will immediately dart from the sealing-wax to the conductor, on which they will be condensed into a kind of net-work resembling wool. If the wire with the sealing-wax be stuck into one of the holes of the conductor, and a piece of paper be presented at a moderate distance from the wax, just after it has been ignited, on setting the machine in motion, a net-work of wax will be formed on the paper. The same effect, but in a slighter degree, will be produced, if the paper be briskly rubbed with a piece of elastic gum, and the melting sealing-wax be held pretty near the paper immediately after rubbing. If the paper thus painted, as it were, with sealing-wax be gently warmed by holding the back of it to the fire, the wax will adhere to it, and the result of the experiment will thus be rendered permanent. _The Electrified Camphor._ A beautiful experiment of the same nature is made with camphor. A spoon holding a piece of lighted camphor is made to communicate with an electrified body, as the prime conductor of a machine; while the conductor continues electrified by keeping the machine in motion, the camphor will throw out ramifications, and appear to shoot like a vegetable. AMUSEMENTS WITH CARDS. Many of the following recreations are performed by arithmetical calculations, and may therefore be considered as connected with science; but as it has been the aim of this work to unite amusement with instruction, some experiments on this subject are introduced, the performance of which depends on dexterity of hand. As this is only to be acquired by practice, and, after all, is merely a mechanical operation, the study of it will produce little useful knowledge, though it may afford much entertainment; but as it must be gratifying to know the method by which they are performed by those persons skilled in such manoeuvres, who publicly exhibit them to the astonishment of the spectator, they are presented to our readers, that when they recognize them at any of these exhibitions, their eyes may not be in danger of deceiving their judgment. _To tell the Number of Points on Three Cards, placed under Three different Parcels of Cards._ You first premise that the ace counts for eleven; the court cards ten each; and the others according to the number of their pips. You then propose to any person in company to choose three cards, and to place over each as many as will make the number of the points of that card, fifteen; take the remaining cards, and, under the appearance of looking for a particular card, count how many there are, and by adding sixteen to that number, you will have the amount of the pips on the three cards. For example: Suppose a person choose a seven, a ten, and an ace; then over the seven he must place eight cards; over the ten, five cards; and over the ace, four cards. In this instance there will remain twelve cards; to which if you add sixteen it will make twenty-eight, which is the amount of the pips on the three cards. _The Ten Duplicates._ Select any twenty cards; let any person shuffle them; lay them by pairs on the board, without looking at them. You next desire several persons, (as many persons as there are pairs on the table,) each to look at different pairs and remember what cards compose them. You then take up all the cards in the order they lay, and replace them with their faces uppermost on the table, according to the order of the letters in the following words: M U T U S 1 2 3 4 5 D E D I T 6 7 8 9 10 N O M E N 11 12 13 14 15 C O C I S 16 17 18 19 20 (These words convey no meaning.)--You will observe, that they contain ten letters repeated, or two of each sort. You therefore ask each person which row or rows the cards he looked at are in; if he say the first, you know they must be the second and fourth, there being two letters of a sort (two U's) in that row; if he say the second and fourth, they must be the ninth and nineteenth, (two I's,) and so of the rest. This amusement, which is very simple, and requires very little practice, will be found to excite, in those who are unacquainted with the key, the greatest astonishment. The readiest way is to have a fac-simile of the key drawn on a card, to which you refer. _To tell how many Cards a Person takes out of a Pack, and to specify each Card._ To perform this, you must so dispose a PIQUET pack of cards, that you can easily remember the order in which they are placed. Suppose, for instance, they are placed according to the words in the following line, _Seven Aces, Eight Kings, Nine Queens, and Ten Knaves;_ and that every card be of a different suite, following each other in this order: spades, clubs, hearts, and diamonds. Then the eight first cards will be the seven of spades, ace of clubs, eight of hearts, king of diamonds, nine of spades, queen of clubs, ten of hearts, and knave of diamonds, and so of the rest. You show that the cards are placed promiscuously, and you offer them with their backs upward to any one, that he may draw what quantity he pleases; you then dexterously look at the card that precedes and that which follows those he has taken. When he has carefully counted the cards, which is not to be done in your presence, (and, in order to give you time for recollection, you tell him to do it twice over, that he may be certain,) you then take them from him, mix them with the pack, shuffle, and tell him to shuffle. During all this time you recollect, by the foregoing line, all the cards he took out; and as you lay them down, one by one, you name each card. Unless a person has a most excellent memory, he had better not attempt the performance of the above amusement, as the least forgetfulness will spoil the whole, and make the operator appear ridiculous. _A Hundred different Names being written on the Cards, to tell the particular Name any Person thought of._ Write on ten cards a hundred different names, observing that the last name on each card begins with one of the letters in the word INDROMACUS, which letters, in the order they stand, answer the numbers 1 to 10, thus: I N D R O M A C U S 1 2 3 4 5 6 7 8 9 10 On ten other cards write the same names, with this restriction, that the first name on every card must be taken from the first of the other cards, whose last name begins with I; the second name must be taken from that whose last name begins with N; and so of the rest. Then let any person choose a card out of the first ten, and after he has fixed on a name, give it to you again, when you carefully note the last name, by which you know the number of that card. You then take the other ten cards, and, after shuffling them, show them to the person, and ask if he sees the name he chose, and when he answers in the affirmative, you look to that name which is the same in number from the top with the number of the card he took from the other parcel, and that will be the name he fixed on. Instead of ten cards there may be twenty to each parcel, by adding duplicates to each card; which will make it appear more mysterious, and will not at all embarrass it, as you have only to remember the last name on each card. Instead of names you may write questions on one of the parcels, and answers on the other. _Several different Cards being fixed on by different Persons, to name that on which each Person fixed._ There must be as many different cards shown to _each person_, as there are cards to choose; so that, if there are three persons, you must show three cards to each person, telling the first to retain _one_ in his memory. You then lay those three cards down, and show three others to the second person, and three others to the third. Next take up the first person's cards, and lay them down separately, one by one, with their faces upwards; place the second person's cards over the first, and the third over the second's, so that there will be one card in each parcel belonging to each person. You then ask each of them in which parcel his card is, and by the answer you immediately know which card it is; for the first person's will always be the first, the second person's the second, and the third person's the third in that parcel where each says his card is. This amusement may be performed with a single person, by letting him fix on three, four, or more cards. In this case you must show him as many parcels as he is to choose cards, and every parcel must consist of that number, out of which he is to fix on one; and you then proceed as before, he telling you the parcel that contains each of his cards. _To name the Rank of a Card that a Person has drawn from a Piquet Pack._ The rank of a card means whether it be an ace, king, queen, &c. You therefore first fix a certain number to each card; thus you call the king four, the queen three, the knave two, the ace one, and the others according to the number of their pips. You then shuffle the cards, and let a person draw any one of them; then turning up the remaining cards, you add the number of the first to that of the second, the second to the third, and so on, till it amounts to ten, which you then reject, and begin again; or if it be more, reject the ten, and carry the remainder to the next card, and so on to the last; and to the last amount add four, and subtract that sum from ten, if it be less, or from twenty, if it be more than ten, and the remainder will be the number of the card that was drawn; as for example, if the remainder be two, the card drawn was a knave; if three, a queen, and so on. _To tell the Amount of the Numbers of any two Cards drawn from a common Pack._ Each court card in this amusement counts for ten, and the other cards according to the number of their pips. Let the person who draws the cards add as many more cards to each of those he has drawn as will make each of their numbers twenty-five. Then take the remaining cards in your hand, and, seeming to search for some card among them, tell them over to yourself, and their number will be the amount of the two cards drawn. For example.--Suppose the person has drawn a ten and a seven, then he must add fifteen cards to the first, to make the number twenty-five, and eighteen to the last, for the same reason; now fifteen and eighteen make thirty-three, and the two cards themselves make thirty-five, which deducted from fifty-two, leave seventeen, which must be the number of the remaining cards, and also of the two cards drawn. You may perform this amusement without touching the cards, thus: Let the person who has drawn the two cards deduct the number of each of them from twenty-six, which is half the number of the pack, and after adding the remainders together, let him tell you the amount, which you privately deduct from fifty-two, the total number of all the cards, and the remainder will be the amount of the two cards. _Example._--Suppose the two cards to be as before, ten and seven; then the person deducting ten from twenty-six, there remain sixteen, and deducting seven from twenty-six, there remain nineteen; these two remainders added together make thirty-five, which you subtract from fifty-two; and there must remain seventeen for the amount of the two cards, as before. _To tell the Amount of the Numbers of any Three Cards that a Person shall draw from the Pack._ After the person has drawn his three cards, draw one yourself and lay it aside, for it is necessary that the number of the remaining cards be divisible by three, which they will not be in a pack of fifty-two cards, if only three be drawn. The card you draw, you may call the confederate, and pretend it is by the aid of that card you discover the amount of the others. Then tell the party to add as many more to each of his cards as will make its number sixteen, which is the third part of the remaining forty-eight cards; therefore, suppose he has drawn a ten, a seven, and a six; then, to the first he must add six cards, to the second nine, and to the third ten, which together make twenty-five, and the four cards drawn being added to them make twenty-nine. You then take the remaining cards, and, telling them over, as in the last amusement, you find their number to be twenty-three, the amount of the three cards the person drew. This amusement may also be performed without touching the cards, thus:--When the party has drawn his three cards, and you have drawn one, let him deduct the number of each of the cards he has drawn from seventeen, which is one-third of the pack after you have drawn your card; and let him tell you the amount of the several remainders, to which you privately add one to the card you drew, and, deducting that amount from fifty-two, (the whole number of the cards,) the remainder will be the amount of the three cards drawn. _Example._--Suppose the three cards to be ten, seven, and six, as before; then, each of those numbers subtracted from seventeen, the remainders will be respectively, seven, ten, and eleven, which, added together, make twenty-eight, to which the single card you drew being reckoned as one, and added, makes twenty-nine; and that number deducted from fifty-two, leaves twenty-three, which is the amount of the three cards the party drew. * * * * * The following amusements principally depend on dexterity of hand; and, as what is termed _making the pass_, will be necessary to be acquired, to enable the operator to perform many of them, we subjoin the following explanation of this term: _How to make the Pass._--Hold the pack of cards in your right hand, so that the palm of your hand may be under the cards: place the thumb of that hand on one side of the pack; the first, second, and third fingers on the other side, and your little finger between those cards that are to be brought to the top, and the rest of the pack. Then place your left hand over the cards in such a manner that the thumb may be at C, the fore-finger at A, and the other fingers at B, as in the following figure: +----------------+ +----------------+ | _Bottom._ | | _Top._ | | | | | | 2 | | | | | | | | _Thumb._ | | | | 3 | | | | 4 | | | | | | | | | | | |_Little Finger._| | | +----------------+ +----------------+ C The hands and the two parts of the cards being thus disposed, you draw off the lower cards, confined by the little finger and the other parts of the right hand, and place them, with an imperceptible motion, on the top of the pack. But before you attempt any of the tricks that depend on _making the pass_, you must have great practice, and be able to perform it so dexterously and expeditiously, that the eye cannot detect the movement of the hand; or you may, instead of deceiving others, expose yourself. _The Long Card._--Another stratagem, connected with the performance of many of the following tricks, is what is termed the _Long Card_; that is, a card, either a trifle longer or wider than the other cards, not perceptible to the eye of the spectator, but easily to be distinguished by the touch of the operator. _The Divining Card._ Provide a pack in which there is a long card; open it at that part where the long card is, and present the pack to a person in such a manner that he will naturally draw that card. You then tell him to put it into any part of the pack, and shuffle the cards. You take the pack, and offer the same card in like manner to a second or third person, taking care that they do not stand near enough to see the card each other draws. You then draw several cards yourself, among which is the long card, and ask each of the parties if his card be among those cards, and he will naturally say _yes_, as they have all drawn the same card. You then shuffle all the cards together, and, cutting them at the long card, you hold it before the first person, so that the others may not see it, and tell him that is his card. You then put it in the pack, shuffle it, cut it again at the same card, and hold it to the second person. You can perform this recreation without the long card, in the following manner: Let a person draw any card, and replace it in the pack. You then _make the pass_, (see p. 107,) and bring that card to the top of the pack, and shuffle them, without losing sight of that card. You then offer that card to a second person, that he may draw it, and put it in the middle of the pack. You _make the pass_, and shuffle the cards a second time in the same manner, and offer the card to a third person, and so again to a fourth or fifth. _The Four Confederate Cards._ A person draws four cards from the pack, and you tell him to remember one of them. He then returns them to the pack, and you dexterously place two under and two on the top of the pack. Under the bottom ones you place four cards of any sort, and then, taking eight or ten from the bottom cards, you spread them on the table, and ask the person if the card he fixed on be among them. If he say _no_, you are sure it is one of the two cards on the top. You then pass those two cards to the bottom and, drawing off the lowest of them, you ask if that is not his card. If he again say _no_, you take up that card, and bid him draw his card from the bottom of the pack. If, on the contrary, he say his cards _are_ among those you _first_ drew from the bottom, you must dexterously take up the four cards you put under them, and, placing those on the top, let the other two be the bottom cards of the pack, which you are to draw in the manner before described. _The Numerical Cards._ Let the long card be the sixteenth in the pack of piquet cards. Take ten or twelve cards from the top of the pack, and, spreading them on the table, desire a person to think on any one of them, and to observe the number it is from the first card. Make the pass at the long card, which will then be at the bottom. Then ask the party the number his card was at, and, counting to yourself from that number to sixteen, turn the cards up, one by one, from the bottom. Then stop at the seventeenth card, and ask the person if he has seen his card, when he will say _no_. You then ask him how many more cards you shall draw before his card appears; and when he has named the number, you draw the card aside with your finger, turn up the number of cards he proposed, and throw down the card he fixed on. _The Card found out by the Point of the Sword._ When a card has been drawn, you place it under the long card, and by shuffling them dexterously, you bring it to the top of the pack. Then lay or throw the pack on the ground, observing where the top card lies. A handkerchief is then bound round your eyes, which ought to be done by a confederate, in such a way that you can see the ground. A sword is put into your hand, with which you touch several of the cards, as if in doubt, but never losing sight of the top card, in which at last you fix the point of the sword, and present it to the party who drew it. _The Card hit upon by the Guess._ Spread part of the pack before a person, in such way that only one court card is visible; and so arrange it, that it shall appear the most prominent and striking card. You desire him to think on one; and observe if he fix his eye on the court card. When he tells you he has determined on one, shuffle the cards, and, turning them up one by one, when you come to the court card tell him that is the one. If he does not seem to fix his eye on the court card, you should not hazard the experiment; but frame an excuse for performing some other amusement; neither should it be attempted with those who are conversant with these sort of deceptions. _The Card changed by Word of Command._ You must have two cards of the same sort in the pack, (say the king of spades.) Place one next the bottom card, (say seven of hearts,) and the other at top. Shuffle the cards without displacing those three, and show a person that the bottom card is the seven of hearts. This card you dexterously slip aside with your finger, which you have previously wetted, and, taking the king of spades from the bottom, which the person supposes to be the seven of hearts, lay it on the table, telling him to cover it with his hand. Shuffle the cards again, without displacing the first and last card, and, shifting the other king of spades from the top to the bottom, show it to another person. You then draw that privately away, and, taking the bottom card, which will then be the seven of hearts, you lay that on the table, and tell the second person (who believes it to be the king of spades) to cover it with his hand. You then command the cards to change places; and when the two parties take off their hands and turn up the cards, they will see, to their great astonishment, that your commands are obeyed. _The Three Magical Parties._ Offer the long card to a person, that he may draw it, and replace it in any part of the pack he pleases. _Make the pass_, and bring that card to the top. Next divide the pack in three parcels, putting the long card in the middle heap. You then ask the person which of the three heaps his card shall be in. He will, probably, say the middle; in which case you immediately show it to him. But if he say either of the others, you take all the cards in your hand, placing the parcel he has named over the other two, and observing to put your little finger between that and the middle heap, at the top of which is the card he drew. You then ask at what number in that heap he will have his card appear. If, for example, he say the sixth, you tell down five cards from the top of the pack, and then, dexterously making the pass, you bring the long card to the top, and tell it down as the sixth. _The Magic Vase._ Construct a vase of wood, or pasteboard, see Fig. 20. On the inside let there be five divisions; two of them, _c d_, to be large enough to admit a pack of cards each; and the other three, _e f g_, only large enough to contain a single card. Place this vase on a bracket, L, which is fastened to the partition M. Fix a silken thread at H, the other end of which passes down the division _d_, and, over the pulley I, runs along the bracket L, and goes out behind the partition M. [Illustration: Fig. 20.] Take three cards from the piquet pack, and place one of them in each of the divisions _e f g_, making the silk thread or line go under each of them. In the division _c_ put the remainder of the pack. You then get another pack of cards, at the top of which are to be three cards, the same as those in the three small divisions: and, making the pass, bring them to the middle of the pack. Let them be drawn by three persons; let them shuffle all the cards; after which place the pack in the division _d_, and tell the parties that the cards they drew will rise at their command, separately, from the vase. A confederate behind the partition then gently drawing the line, the three cards will then gradually appear from the vase; then taking the cards from _c_, you show that those three are gone from the pack. The vase must be placed so high that the company cannot see the inside. _The Divining Perspective Glass._ Procure a small perspective-glass, wide enough, where the object-glass is placed, to hold the following table: +-------+--------+--------+ | 1,131 | 10,132 | 19,133 | | 2,231 | 11,232 | 20,233 | | 3,331 | 12,332 | 21,333 | +-------+--------+--------+ | 4,121 | 13,122 | 22,123 | | 5,221 | 14,222 | 23,223 | | 6,321 | 15,322 | 24,323 | +-------+--------+--------+ | 7,111 | 16,112 | 25,113 | | 8,211 | 17,212 | 26,213 | | 9,311 | 18,312 | 27,313 | +-------+--------+--------+ Take a pack of twenty-seven cards; give them to a person, bid him fix, on one, shuffle them, and return them to you. Arrange the twenty-seven cards in three parcels, by laying one down, alternately, on each parcel; but before you lay each card down, show it to the person, without seeing it yourself. When you have completed the three parcels, ask him at what number, from one to twenty-seven, he will have his card appear, and in which heap it then is. You then look at the heap through your glass; and if the first of the three numbers, which stands against the number it is to appear at, be one, put that heap at top; if the number be at two, put it in the middle; and if it be three, put it at the bottom. Next divide the cards into three heaps, in the same manner, a second and third time, and his card will be at the number he chose. _Example._--Suppose the person wishes his card to be the twentieth from the top; and the first time of making the heaps, he says it is in the third heap; you then look at the table in the perspective, and you see that the first figure is two; you, therefore, put that heap in the middle of the pack. The second and third times, you in like manner put the heap in which he says it is, at bottom; the number each time being three. Then looking at the pack with your glass, as if to discover which the card was, you lay the cards down, one by one, and the twentieth will be the card fixed on. _The Card in the Ring._ Get a ring, made of any metal, in which is set a large transparent stone or piece of glass, to the bottom of which is fastened a small piece of black silk; under the silk is to be the figure of a small card; and the silk must be so constructed that it may be either drawn aside or spread, by turning the stone round. You then cause a person to draw the same sort of card as that at the bottom of the ring; and tell him to burn it in the candle. Now, the ring being so constructed that the silk conceals the card underneath it, you first show him the ring, that he may see it is not there, and tell him you will make it appear; then rubbing the ashes of the card on the ring, you manage to turn the stone or glass dexterously round, and exhibit to him the small card at the bottom. _The Card in the Mirror._ Provide a mirror, either round or oval, the frame of which must be at least as wide as a card, and the glass must be wider than the distance between the frame, by at least the width of a card. The glass in the middle must be made to move in two grooves, and so much of the quicksilver must be scraped off, as is equal to the size of a common card. You then paste over the part where the quicksilver is rubbed off, a piece of pasteboard, on which is a cord, that must exactly fit the space, which must at first be placed behind the frame. Fix this mirror against a partition, through which two strings are to go, by which an assistant in an adjoining room can easily move the glass in the grooves, and make the card appear or disappear at pleasure. Or it may be done without an assistant, if a table be placed against the partition, and a string from the glass be made to pass through a leg of it, and communicate with a small trigger, which you may easily push down with your foot, and at the same time wiping the glass with your handkerchief, under the pretence that the card may appear more conspicuous; which will also serve most effectually to disguise the operation. Having every thing thus arranged, you contrive to make a person draw the same sort of card as that fixed to the mirror; if you do not succeed in this with a stranger, make some pretence for shuffling the cards again, and present the pack to a confederate, who, of course, will draw the card you wish, and who is to show it to two or three persons next to him, under the pretence that it might slip his memory. This card you place in the middle of the pack, then _make the pass_, and bring it to the bottom. Direct the person to look for his card in the mirror, which the confederate behind the partition is to draw slowly forward; or if you perform the operation yourself, press the trigger with your foot, and the card will appear as if placed between the glass and the quicksilver. While the glass is drawing forward, you slide off the card from the bottom of the pack, and convey it away. _The Card in the Opera Glass._ Procure an opera-glass, two inches and a half long; the tube to be made of ivory, so thin that it may appear transparent. Place it in a magnifying glass, of such a power, and at such a distance, that a card, three-quarters of an inch long, may appear like a common-sized card. At the bottom of the tube lay a circle of black pasteboard, to which fasten a small card, with the pips, or figures, on both sides, and in such a manner, that by turning the table, either side of the glass may be visible. You then offer two cards to two persons, similar to the double card in the glass. You put them in the pack again, or convey them to your pocket; and after a few flourishing motions you tell the persons you have conveyed their cards into the glass; then you show each person his card in the glass, by turning it in the proper position. You may easily induce the parties to draw the two cards you wish, by placing them first on the top of the pack, and then, by making the pass, bringing them to the middle. When you can make the pass in a dexterous manner, it is preferable to the long card, which obliges the operator to change the pack frequently, as, if the same card is always drawn, it may excite suspicion. _To separate the two Colours of a Pack of Cards by one Cut._ To perform this amusement, all the cards of one colour must be cut something narrower at one end than the other. You show the cards, and give them to any one, that he may shuffle them; then holding them between your hands, one hand being at each extremity, with one motion you separate the hearts and diamonds from the spades and clubs. _The Metamorphosed Cards._ In the middle of a pack place a card that is something wider than the rest, which we will suppose to be the knave of spades, under which place the seven of diamonds, and under that the ten of clubs. On the top of the pack put cards similar to these, and others on which are painted different objects, _viz._: First card A bird Second A seven of diamonds Third A flower Fourth Another seven of diamonds Fifth A bird Sixth A ten of clubs Seventh A flower Eighth Another ten of clubs; then seven or eight indifferent cards, the knave of spades, which is the wide card, the seven of diamonds, the ten of clubs, and the rest any indifferent cards. Two persons are to draw the two cards that are under the wide card, which are the seven of diamonds and the ten of clubs. You take the pack in your left hand, and open it at the wide end, as you open a book, and tell the person who drew the seven of diamonds to place it in that opening. You then blow on the cards, and, without closing them, instantly bring the card which is at top, and on which a bird is painted, over that seven of diamonds. To do this dexterously, you must wet the middle finger of your left hand, with which you are to bring the card to the middle of the pack. You then bid the person look at his card, and when he has remarked the change, to place it where it was before. Then blow on the cards a second time, and, bringing the seven of diamonds, which is at the top of the pack, to the opening, you bid him look at his card again, when he will see it is that which he drew. You may do the same with all the other painted cards, either with the same person, or with him who drew the ten of clubs. The whole artifice consists in bringing the card at the top of the pack to the opening in the middle, by the wet finger, which requires no great practice. Observe, not to let the pack go out of your hands. _To discover the Card which is drawn, by the Throw of a Die._ Prepare a pack of cards, in which there are only six sorts of cards. Dispose these cards in such manner that each of the six different cards shall follow each other, and let the last of each suite be a long card. The cards being thus disposed, it follows, that if you divide them into six parcels, by cutting at each of the long cards, those parcels will all consist of similar cards. Let a person draw a card from the pack, and let him replace it in the parcel from whence it was drawn, by dexterously offering that part. Cut the cards several times, so that a long card be always at bottom. Divide the cards in this manner into six heaps, and giving a die to the person who drew the card, tell him that the point he throws shall indicate the parcel in which is the card he drew; then take up the parcel and show him the card. _To tell the Number of the Cards by their Weight._ Take a parcel of cards, suppose forty, among which insert two long cards; let the first be, for example, the fifteenth, and the other the twenty-sixth from the top. Seem to shuffle the cards, and then cutting them at the first long card, poise those you have cut off in your left hand, and say, "There should be here fifteen cards." Cut them again at the second long card, and say, "There are here only eleven cards." Then poising the remainder, you say, "Here are fourteen cards." _The Four Inseparable Kings._ Take the four kings, and behind the last of them place two other cards, so that they may not be seen. Then spread open the four kings to the company, and put the six cards at the bottom of the pack. Draw one of the kings, and put it at the top of the pack. Draw one of the two cards at the bottom, and put it towards the middle. Draw the other, and put it at some distance from the last, and then show that there remains a king at bottom. Then let any one cut the cards, and as there remains three kings at bottom, they will then be altogether in the middle of the pack. _To change the Cards which several Persons have drawn from the Pack._ On the top of the pack put any card you please--suppose the queen of clubs; make the pass, bring that card to the middle of the pack, and offer it to a person to draw. Then, by cutting the cards, bring the queen again to the middle of the pack. Make the pass a second time, bring it to the top, and shuffle the cards without displacing those on the top. Make the pass a third time, bring it to the middle of the pack and offer it to a second person to draw, who must be at a proper distance from the first person, that he may not perceive it is the same card. After the like manner let five persons draw the same card. Shuffle the pack without losing sight of the queen of clubs, and, laying down four other cards with the queen, ask each person if he see his card there? They will all reply, "Yes," as they all drew the queen of clubs. Place four of those cards on the pack, and, drawing the queen privately away, you approach the first person, and showing him that card, so that the others cannot see it, ask if that be his card; then patting it on the top of the pack, blow on it, or give it a stroke with your hand, and show it in the same manner to the second person, and so of the rest. _The Card discovered under the Handkerchief._ Let a person draw any card from the rest, and put it in the middle of the pack; you make the pass at that place, and the card will consequently be at top; then placing the pack on the table, cover it with a handkerchief; and, putting your hand under it, take off the top card, and after seeming to search among the cards for some time, draw it out. This amusement may be performed by putting the cards in another person's pocket, after the pass is made. Several cards may also be drawn and placed together in the middle of the pack, and the pass then made. _The Convertible Aces._ On the ace of spades fix, with soap, a heart, and on the ace of hearts a spade, in such a manner that they will easily slip off. Show these two aces to the company; then, taking the ace of spades, you desire a person to put his foot upon it, and as you place it on the ground, draw away the spade. In like manner you place the seeming ace of hearts under the foot of another person. You then command the two cards to change their places; and that they obey your command, the two persons, on taking up their cards, will have ocular demonstration. A deception similar to this is sometimes practised with one card, suppose the ace of spades, over which a heart is pasted lightly. After showing a person the card, you let him hold one end of it, and you hold the other, and while you amuse him with discourse, you slide off the heart. Then laying the card on the table, you bid him cover it with his hand; you then knock under the table, and command the heart to turn into the ace of spades. _To tell the Card that a Person has touched with his Finger._ This amusement is to be performed by confederacy. You previously agree with your confederate on certain signs, by which he is to denote the suite, and the particular card of each suite; thus: if he touch the first button of his coat, it signifies an ace; if the second, a king, &c.; and then again, if he take out his handkerchief, it denotes the suite to be hearts; if he take snuff, diamonds, &c. These preliminaries being settled, you give the pack to a person who is near your confederate, and tell him to separate any one card from the rest, while you are absent, and draw his finger once over it. He is then to return you the pack, and while you are shuffling the cards, you carefully note the signals made by your confederate; then turning the cards over one by one, you directly fix on the card he touched. _The Card in the Pocket-book._ A confederate is previously to know the card you have taken from the pack, and put into your pocket-book. You then present the pack to him, and desire him to fix on a card, (which we will suppose to be the queen of diamonds,) and place the pack on the table. You then ask him the name of the card, and when he says the queen of diamonds, you ask him if he be not mistaken, and if he be sure that the card is in the pack: when he replies in the affirmative, you say, "It might be there when you looked over the cards, but I believe it is now in my pocket;" then desire a third person to put his hand in your pocket, and take out your book, and when it is opened the card will appear. _The Card in the Egg._ Take a card, the same as your long card, and, rolling it up very close, put it in an egg, by making a hole as small as possible, and which you are to fill up carefully with white wax. You then offer the long card to be drawn, and when it is replaced in the pack, you shuffle the cards several times, giving the egg to the person who drew the card, and while he is breaking it, you privately withdraw the long card, that it may appear, upon examining the cards, to have gone from the pack into the egg. This may be rendered more surprising by having several eggs, in each of which is placed a card of the same sort, and then giving the person the liberty to choose which egg he thinks fit. This deception may be still further diversified, by having, as most public performers have, a confederate, who is previously to know the egg in which the card is placed; for you may then break the other eggs, and show that the only one that contains a card is that in which you directed it to be. _The Card discovered by the Touch or Smell._ You offer the long card, or any other that you know, and as the person who has drawn it holds it in his hand, you pretend to feel the pips or figure on the under side, by your fore-finger; or you sagaciously smell to it, and then pronounce what card it is. If it be the long card, you may give the pack to the person who drew it, and leave him at liberty either to replace it or not. Then taking the pack, you feel immediately whether it be there or not, and, shuffling the cards in a careless manner, without looking at them, you pronounce accordingly. _The Inverted Cards._ Prepare a pack of cards, by cutting one end of them about one-tenth of an inch narrower than the other; then offer the pack to any one, that he may draw a card; place the pack on the table, and observe carefully if he turn the card while he is looking at it; if he do not, when you take the pack from the table, you offer the other end of it for him to insert that card; but if he turn the card, you then offer him the same end of the pack. You afterwards offer the cards to a second or third person, for them to draw or replace a card in the same manner. You then let any one shuffle the cards, and, taking them again into your own hand, as you turn them up one by one, you easily perceive by the touch which are those cards that have been inverted, and, laying the first of them down on the table, you ask the person if that card be his; and if he say _no_, you ask the same of the second person; and if he say _no_, you tell the third person it is his card; and so of the second or third cards. You shall lay the pack on the table after each person has drawn his card, and turn it dexterously in taking it up, when it is to be turned, that the experiment may not appear to depend on the cards being inverted. _The Transmuted Cards._ In a common pack of cards let the ace of hearts and nine of spades be something larger than the rest. With the juice of lemon draw over the ace of hearts a spade, large enough to cover it entirely, and on each side draw four other spades. Present the pack to two persons, so adroitly, that one of them shall draw the ace of hearts, and the other the nine of spades, and tell him who draws the latter, to burn it on a chafing-dish. You then take the ashes of that card, put them into a small metal box, and give it to him that has the ace of hearts, that he may himself put that card into the box and fasten it. Then put the box for a short time on the chafing-dish, and let the person who put the card in it take it off, and take out the card, which he will see is changed into the nine of spades. _The Convertible Cards._ To perform this amusement you must observe, that there are several letters which may be changed into others, without any appearance of the alteration, as the _a_ into _d_, the _c_ into _a_, _e_, _d_, _g_, _o_, or _q_; the _i_ into _b_, _d_, or _l_; the _l_ into _t_; the _o_ into _a_, _d_, _g_, or _q_; the _v_ into _y_, &c. Take a parcel of cards, suppose twenty, and on one of them write with juice of lemon or onion, or vitriol and water, the word law, (these letters should not be joined;) and on the other, with the same ink, the words _old woman_; then holding them to the fire, they both become visible. Now, you will observe, that by altering the _a_ in the word _law_ into _d_, and adding _o_ before the _l_, and _oman_ after the _w_, it becomes _old woman_. Therefore you make those alterations with the invisible ink, and let it remain so. On the rest of the cards you write any words you think fit. Present the cards in such manner to two persons, that one of them shall draw the word _law_, and the other the words _old woman_. You then tell the person who drew the word _law_, that it shall disappear, and the words on the other card shall be written in its place; and, that you may not change the cards, desire each of the parties to write his name on his card. Then putting the cards together, and holding them before the fire, as if to dry the names just written, the word _law_ will presently change into _old woman_. _The Enchanted Palace._ On the six-sided plane A B C D E F, Fig. 21, draw six semi-diameters; and on each of these place perpendicularly two plane mirrors, which must join exactly at the centre, and which, placed back to back, must be as thin as possible. Decorate the exterior boundary of this piece, (which is at the extremity of the angles of the hexagon,) with six columns, that at the same time serve to support the mirrors by grooves formed on their inner sides. Add to these columns their entablatures, and cover the edifice in whatever manner you please. In each one of these six triangular spaces, contained between two mirrors, place little figures of pasteboard, in relief, representing such subjects, as, when seen in an hexagonal form, will produce an agreeable effect. To these add small figures of enamel, and take particular care to conceal by some object that has no relation to the subject, the place where the mirrors join, which, as before observed, all meet in the common centre. [Illustration: Fig. 21.] When you look into any one of the six openings of this palace, the objects there contained, being reflected six times, will seem entirely to fill up the whole of the building. This illusion will appear very remarkable, especially if the objects chosen are properly adapted to the effect which the mirrors are intended to produce. If you place between two of these mirrors part of a fortification, as a curtain, and two demi-bastions, you will see an entire citadel with six bastions; or if you place part of a ball-room, ornamented with chandeliers and figures, all these objects being here multiplied, will afford a very pleasing prospect. _Opaque Bodies seemingly Transparent._ Within the case A B C D, place four mirrors O P Q R, Fig. 22, so disposed, that they may each make an angle of 45 degrees, that is, that they may be half-way inclined from the perpendicular, as in the figure. In each of the two extremities A B, make a circular overture; in one of which fix the tube G L, in the other the tube M F, and observe, that in each of these is to be inserted another tube, as H and I. [_Observe._ These four tubes must terminate in the substance of the case, and not enter the inside, that they may not hinder the effect of the mirrors. The four-fold reflection of the rays of light from the mirrors, darkens in some degree the brightness of the object; some light is also lost by the magnifying power of the perspective. If, therefore, instead of the object-glass at G, and concave eye-glass at F, plain glasses were substituted, the magnifying power of the perspective will be taken away, and the object appear brighter.] [Illustration: Fig. 22.] Furnish the first of these tubes with an object-glass at G, and a concave eye-glass at F. You are to observe, that in regulating the focus of these glasses with regard to the length of the tube, you are to suppose it equal to the line G, or visual pointed ray, which entering at the aperture G is reflected by the four mirrors, and goes out at the other aperture F, where the eye-glass is placed. Put any glass you please into the two ends of the moveable tubes H and L; and lastly, place the machine on stand E, moveable at the point S, that it may be elevated or lowered at pleasure. When the eye is placed at F, and you look through the tube, the rays of light that proceed from the object T, passing through the glass G, are successively reflected by the mirrors O P Q and R to the eye at F, and there point the object T in its proper situation, and these rays appear to proceed directly from that object. The two moveable tubes H and I, at the extremity of which a glass is placed, serve only to disguise the illusion, for they have no communication with the interior of the machine. This instrument being moveable on the stand E, may be directed to any object; and if furnished with proper glasses, will answer the purpose of common perspective. The two moveable tubes, H and I, being brought together, the machine is directed towards any object; and, desiring a person to look at the end F, you ask him if he sees that object distinctly. You then separate the two moveable tubes, and, leaving space between them sufficiently wide to place your hand or any other solid body, you tell him that the machine has the power of making objects visible through the most opaque body; and as a proof, you desire him to look at the same object, when to his great surprise he will see it as distinctly as if no solid body interposed. This experiment is the more extraordinary as it is very difficult to conceive how the effect is produced; the two arms of the case appearing to be made for the purpose of supporting the perspective-glass; and to whatever object it be directed, the effect is still the same. _The Deforming Mirrors._ If a person look in a concave mirror placed perpendicularly to another, (that is, supposing one mirror to be laid on the floor, and the other attached to the ceiling,) his face will appear entirely deformed. If the mirror be a little inclined, so as to make an angle of 80 degrees, (that is, one-ninth part from the perpendicular,) he will then see all the parts of his face, except the nose and forehead. If it be inclined to 60 degrees; (that is, one-third part,) he will appear with three noses and six eyes: in short, the apparent deformity will vary at each degree of inclination, and when the glass comes to 45 degrees, (that is, half-way down,) the face will vanish. If, instead of placing the two mirrors in this situation, they are so disposed that their junction may be vertical, then different inclinations will produce other effects, as the situation of the object relative is quite different. _The Magic Tube._ Procure a small tube of glass, whose canal is extremely narrow, and open at both ends; let one end of it be plunged in water, and the water within the tube will rise to a considerable height above the external surface: or if two or more tubes be immersed in the same fluid, the one with a narrow canal, and the other wider, the water will ascend higher in the former than the latter. _The Magician's Mirror._ Construct a box of wood, of a cubical shape, A B C D, Fig. 23, of about fifteen inches every way. Let it be fixed to the pedestal P, at the usual height of a man's head. In each side of this box let there be an opening, of an oval form, ten inches high, and seven wide. In this box place two mirrors, A D, with their backs against each other. Let them cross the box in a diagonal line, and in a vertical position. Decorate the openings in the side of this box with four oval frames and transparent glasses, and cover each with a curtain so contrived as all to draw up together. [Illustration: Fig. 23.] Place four persons in front of the four sides, and at equal distances from the box, and then draw them up that they may see themselves in the mirrors, when each of them, instead of his own figure, will see that of the person next to him, but who will appear to him to be placed on the opposite side. Their confusion will be the greater, as it will be very difficult, if not impossible, for them to discover the mirrors concealed in the box. The reason of this phenomenon is evident; for though the rays of light may be turned aside by a mirror, yet they always _appear_ to proceed in right lines. _The Perspective Mirror._ Provide a box, A B C D, Fig. 24, of about two feet long, 15 inches wide, and 12 inches high. At the end A C, place the concave mirror, the focus of whose parallel rays is 18 inches from the reflecting surface. At I L place a pasteboard, blacked, in which a hole is cut, sufficiently large to see on the mirror H the object placed at B E F D. Cover the top of the box, from A to I, close, that the mirror H may be entirely darkened. The other part, I B, must be covered with glass, under which is placed a gauze, or oiled paper, to prevent the inside from being seen. Make an aperture at G, near the top of the side E B, beneath which, on the inside, place in succession, paintings of vistas, landscapes, figures, &c., so that they may be in front of the mirror H. Let the box be placed that the objects may be strongly illuminated by the sun, or by wax-lights placed under the enclosed part of the box A I. By this simple construction, the objects placed at G D will be thrown into their natural perspective, and if the subjects be properly chosen and well executed, the appearance will be both wonderful and pleasing. [Illustration: Fig. 24.] _Gunpowder Exploded by Reflection._ Place two concave mirrors at about 12 or 15 feet distance from each other, and let the axis of each be in the same line. In the focus of one of them place a live coal, and in the focus of the other place some gunpowder. With a pair of double bellows, which make a continual blast, keep constantly blowing the coal, and notwithstanding the distance between them, the powder will presently take fire. _The Igniting Mirrors._ The rays of a luminous body placed in the focus of concave mirror, being reflected in parallel lines, and a second mirror being placed diametrically opposite to the first, will set fire to a combustible body, by collecting those rays in the focus. _The Armed Apparition._ If a person with a drawn sword place himself before a large concave mirror, but further from it than its focus, he will see an inverted image of himself in the air, between him and the mirror, of a less size than himself. If he steadily present the sword towards the centre of the mirror, an image of the sword will come out from it, point to point, as if to fence with him; and by his pushing the sword nearer, the image will appear to come nearer to him, and almost to touch his breast. If the mirror be turned 45 degrees, or one-eighth round, the reflected image will go out perpendicularly to the direction of the sword presented, and apparently come to another person placed in the direction of the motion of the image, who, if he be unacquainted with the experiment, and does not see the original sword, will be much surprised and alarmed. _The Phantom._ You inform a person that at a certain hour, and in a certain place, he shall see the apparition of a deceased friend, (whose portrait you possess.) In order to produce this phantom, there must be a door which opens into an apartment to which there is a considerable descent. Under that door you are to place the portrait, which must be inverted and strongly illuminated, that it may be brightly reflected by the mirror, which must be large and well polished. Then having introduced the incredulous spectator at another door, and placed him in the proper point of view, you suddenly throw open the door, when to his great surprise he will view the apparition of his friend. _The Distorting Mirror._ Opticians sometimes grind a glass mirror concave in one direction only, or longitudinally; it is in fact a concave portion of a cylinder, the breadth of which may be considered that of the mirror. A person looking at his face in this mirror, in the direction of its concavity, will see it curiously distorted in a very lengthened appearance; and by turning the cylindrical mirror a quarter round, his visage will appear distorted another way, by an apparent increase in width only. If in a very near situation before it, you put your finger on the right hand side of your nose, it will appear the same in the mirror; but if in a distant situation, somewhat beyond the centre of concavity, you again look at your face in the mirror, your finger will appear to be removed to the other side of your nose. _Water colder than Ice._ Put a lump of ice into an equal quantity of water, heated to 176 degrees, the result will be, that the fluid will be no hotter than water just beginning to freeze; but if a little sea salt be added to the water, and it be heated only to 166 or 170, a fluid will be produced _colder than the ice was at first_. _Exploding Salt._ If a small quantity of powdered charcoal and hyper-oxymuriate of potash be rubbed together in a mortar, an explosion will be produced, and the charcoal inflamed. Three parts of this salt, and one of sulphur, rubbed together in a mortar, produce a violent detonation. If struck with a hammer on an anvil, there is an explosion like the report of a pistol. When concentrated sulphuric acid is poured upon this salt, there is a considerable explosion; it is thrown about to a great distance, sometimes with a red flame; and there is exhaled a brown vapour, accompanied with a strong odour. _Dioptrical Paradox._ Construct a machine similar to that in Fig. 25. Its effect will be, that a print, or an ornamented drawing, with any object, such as an ace of diamonds, &c. in the centre F, will be seen as an ace of clubs when placed in the machine, and viewed through a single plane glass only, contained in the tube E. The glass in the tube F, which produces this surprising change, is somewhat on the principle of the common multiplying glass, as represented at G, which, by the number of its inclined surfaces, and from the refractive power of the rays proceeding from the objects placed before it shows it in a multiplied state. The only difference is, that the sides of this glass are flat, and diverge upwards from the base to a point in the axis of the glass like a cone; it has six sides, and each side, from its angular position to the eye, has the property of refracting from the border of the print F, such a portion of it (designedly placed there) as will make a part in the composition of the figure to be represented; for the hexagonal and conical figure of this glass prevents any part of the ace of diamonds being seen; consequently the ace of clubs being previously and mechanically drawn in the circle of refraction in six different parts of the border, at 1, 2, 3, 4, 5, 6, and artfully disguised in the ornamental border, by blending them with it, the glass in the tube at E will change the appearance of the ace of diamonds, F, into the ace of clubs, G. In the same manner many other prints undergo similar changes, according to the will of an ingenious draughtsman who may design them. The figure of the glass is shown at H. [Illustration: Fig. 25.] _To show the Spots in the Sun's Disk by its Image in the Camera Obscura._ Put the object-glass of a ten or twelve feet telescope into the scioptric ball, and turn it about till it be directly opposite the sun. Then place the pasteboard mentioned in page 16, in the focus of the lens, and you will see a clear bright image of the sun, about an inch diameter, in which the spots on the sun's surface will be exactly described. As this image is too bright to be seen with pleasure by the naked eye, you may view it through a lens whose focus is at six or eight inches distance, which, while it prevents the light from being offensive, will, by magnifying both the image and the spot, make them appear to greater advantage. _The Diagonal Opera Glass._ By the diagonal position of a plane mirror, a curious opera-glass is constructed, by which any person may be viewed in a theatre or public company without knowing it. It consists only in placing a concave glass near the plane mirror, in the end of a short round tube, and a convex glass in a hole in the side of the tube, then holding the end of the tube with the glass to the eye, all objects next to the hole in the side will be reflected so as to appear in a direct line forward, or in a position at right angles to the person's situation who is looked at. Plane glasses, instead of a convex and concave, may be used; in this case the size of the object will not be increased, but it will appear brighter. _To observe an Eclipse of the Sun, without Injury to the Eye._ Take a burning-glass, or spectacle-glass, that magnifies very much; hold it before a book or pasteboard, twice the distance of its focus, and you will see the round body of the sun, and the manner in which the moon passes between the glass and the sun, during the whole eclipse. _The Burnt Writing restored._ Cover the outside of a small memorandum book with black paper, and in one of its inside covers make a flap, to open secretly, and observe there must be nothing over the flap but the black paper that covers the book. Mix soot with black or brown soap, with which rub the side of the black paper next the flap; then wipe it clean, that a white paper pressed against it will not receive any mark. Provide a black-lead pencil that will not mark without pressing hard on the paper. Have likewise a small box, about the size of a memorandum book, and that opens on both sides, but on one of them by a private method. Give a person a pencil and a slip of thin paper, on which he is to write what he thinks proper; you present him the memorandum book at the same time, that he may not write on the bare paper. You tell him to keep what he writes to himself, and direct him to burn it on the iron plate laid on a chafing-dish of coals, and give you the ashes. You then go into another room to fetch your magic box, before described, and take with you the memorandum book. Having previously placed a paper under the flap in the cover of the book, when he presses hard with the pencil, to write on his paper, every stroke, by means of the stuff rubbed on the black paper, will appear on that under the flap. You therefore take it out, and put it into one side of the box. You then return to the other room, and taking a slip of black paper, you put it into the other side of the box, strewing the ashes of the burnt paper over it. Then shaking the box for a few moments, and at the same time turning it dexterously over, you open the other side, and show the person the paper you first put in, the writing on which he will readily acknowledge to be his. If there be a press or cupboard that communicates with the next room, you need only put the book in the press, and your assistant will open it, and put the paper in the box, which you presently after take out, and perform the rest of the amusement as before. There may likewise be a flap on the other cover of the book; and you may rub the paper against that with red lead. In this case you give the person the choice of writing either with a black or red pencil; and present him the proper side of the book accordingly. _The Opaque Box made Transparent._ Make a box three or four inches long, and two or three wide, and have a sort of perspective-glass, the bottom of which is the same size with the box, and slides out, that you may privately place a paper on it. The sides of this perspective are to be of glass, covered on the inside with fine paper. Let a person write on a slip of paper, putting your memorandum book under it, as in the last amusement; then give him the little box, and let him put what he has written into it. In the mean time you put the memorandum book into the press, where the perspective is already placed. Your assistant then takes the paper out of the book, and puts it at the bottom of the perspective; which you presently take out of the press, and direct the person to put the little box that contains the paper under it. You then look in at the top of the perspective, and feigning to see through the top of the box, you read what is written on the paper at the bottom of the perspective. With this perspective box you may perform another amusement, which is, by having in a bag twelve or more ivory counters, numbered, which you show to the company, that they may see all the numbers are different. You tell a person to draw any one of them, and keep it close in his hand. You then put the bag in the press, when your assistant examines the counters, and sees which is wanting, and puts another of the same number at the bottom of the perspective, which you then take out, and placing the person's hand close to it, look in at the top, and pretending to see through his hand, you name the number on the counter in it. _The Transposable Pieces._ Take two guineas and two shillings, and grind part of them away, on one side only, so that they may be but half the common thickness; and observe, that they must be quite thin at the edge; then rivet a guinea and a shilling together. Lay one of these double pieces, with the shilling upwards, on the palm of your hand, at the bottom of your three first fingers, and lay the other piece with the guinea upwards in the like manner, in the other hand. Let the company take notice in which hand is the guinea, and in which is the shilling. Then as you shut your hands, you naturally turn the pieces over, and when you open them again, the shilling and the guinea will appear to have changed their places. _The Penetrative Guinea._ Provide a large tin box, of the size of a large snuff-box, and in this place eight other boxes, which will go easily into each other, and let the least of them be of a size to hold a guinea. Each of these boxes should shut with a hinge, and to the least of them there must be a small lock, that is fastened with a spring, but cannot be opened without a key;--observe, that all these boxes must shut so freely, that they may be all closed at once. Place these boxes in each other, with their tops open, in the drawer of the table on which you make your experiments; or, if you please, in your pocket, in such a manner that they cannot be displaced. Then ask a person to lend you a new guinea, and desire him to mark it, that it may not be changed. You take this piece in one hand, and in the other you have another of the same appearance, and putting your hand into the drawer, you slip the piece that is marked into the least box, and shutting them all at once, you take them out; then showing the piece you have in your hand, and which the company suppose to be the same that was marked, you pretend to make it pass through the box, and dexterously convey it away. You then present the box, for the spectators do not yet know there are more than one, to any person in company, who, when he opens it, finds another, and another, till he comes to the last, but that he cannot open without the key, which you then give him, and retiring to a distant part of the room, you tell him to take out the guinea himself, and see if it be that which he marked. This amusement may be made more surprising, by putting the key into the snuff-box of one of the company, which you may do by asking him for a pinch of snuff, and at the same time conceal the key, which must be very small, among the snuff; and when the person, who is to open the box, asks for the key, you tell him that one of the company has it in his snuff-box. This part of the amusement may likewise be performed by means of a confederate. _To make Pictures of Birds with their Natural Feathers._ First take thin board or panel, of deal or wainscot, well seasoned, that it may not shrink; then paste white paper smoothly on it, and let it dry; if the colour of the wood show through, paste a second paper over it. When the paper is dry, get ready any bird that you would represent, and draw the outline as exact as you can on the papered panel. You then paint the ground-work, stump of a tree, the bill and legs, their proper colour, with water-colours, leaving the body to be covered with its own natural feathers. In the space you have left for the body, you lay on very thick gum-water, letting each coat dry before you lay on another, and so continuing until the gum is as thick as a shilling. Then take the feathers off the bird; and, as you proceed, draw a camels'-hair pencil, dipped in gum-water, over the coat of gum that you have laid on the paper, that it may more readily adhere. As you strip the bird, you must fix the feathers in their proper places on the board, and you shave the shafts or stems of the larger feathers, that they may lie flat. The most ready way to perform the operation, is to provide yourself with a pair of steel pliars to take up and lay on the feathers with. You should prepare some small leaden weights to lay on the feathers, that they may more readily adhere to, and lie flat on, the gum. The part where the eye is must be supplied by a small piece of paper, coloured and shaped like one; or you may, probably, be able to get a glass bead that will answer the purpose better. In order that the feathers may lie smooth and regular, when the whole is perfectly dry, lay a book, or a flat board, with a weight on it. _The Art of Bronzing._ Bronzing is that process by which figures of plaster-of-paris, wood, &c. are made to have the appearance of copper or brass. The method is as follows: Dissolve copper filings in aqua fortis. When the copper has impregnated the acid, pour off the solution, and put into it some pieces of iron, or iron filings. The effect of this will be to sink the powder to the bottom of the acid. Pour off the liquor, and wash the powder in successive quantities of fresh water. When the powder is dry, it is to be rubbed on the figure with a soft cloth, or piece of leather; but observe, that previously to the application of the bronze powder, a dark blackish sort of green is first to be laid on the figure: and if you wish the powder to adhere stronger, mix it with gum-water, lay it on like paint, with a camels'-hair brush, or previously trace the parts to be bronzed with gold size, and when nearly dry, rub the powder over it. _Method of taking the Impression of Butterflies on Paper._ Clip the wings off the butterfly, lay them on clean, in the form of a butterfly when flying. Spread some thick clean gum-water on another piece of paper, press it on the wings, and it will take them up; lay a piece of white paper over it, and rub it gently with your finger, or the smooth handle of a knife. The bodies are to be drawn in the space which you leave between the wings. _To soften Horn._ To one pound of wood-ashes, add two pounds of quick lime; put them into a quart of water. Let the whole boil till reduced to one-third. Then dip a feather in, and if, on drawing it out, the plume should come off, it is a proof that it is boiled enough; if not, let it boil a little longer. When it is settled, filter it off, and in the liquor thus strained put in shavings of horn. Let them soak for three days; and, first anointing your hands with oil, work the horn into a mass, and print or mould it into any shape you please. _To make Moulds of Horn._ If you wish to take the impression of any coin, medal, &c., previously anoint it with oil; then lay the horn shavings over it in its softened state. When dry, the impression will be sunk into the horn; and this will serve as a mould to re-produce, either by plaster-of-paris, putty and glue, or isinglass and ground egg-shells, the exact resemblance of the coin or medal. _To cast Figures in Imitation of Ivory._ Make isinglass and strong brandy into a paste, with powder of egg-shells, very finely ground. You may give it what colour you please; but cast it warm into your mould, which you previously oil over. Leave the figure in the mould till dry, and you will find, on taking it out, that it bears a very strong resemblance to ivory. _To extract the Silver out of a Ring that is thick gilded, so that the Gold may remain entire._ Take a silver ring that is thick gilded. Make a little hole through the gold into the silver; then put the ring into aqua fortis, in a warm place: it will dissolve the silver, and the gold will remain whole. _To soften Iron or Steel._ Either of the following simple methods will make iron or steel as soft as lead: 1. Anoint it all over with tallow; temper it in a gentle charcoal fire, and let it cool of itself. 2. Take a little clay, cover your iron with it, temper it in a charcoal fire. 3. When the iron or steel is red-hot, strew hellebore on it. 4. Quench the iron or steel in the juice or water of common beans. _To take a Plaster-of-Paris Cast from a Person's Face._ The person must lie on his back, and his hair be tied behind. Into each nostril put a conical piece of paper, open at each end to allow of breathing. The face is to be lightly oiled over, and the plaster being properly prepared is to be poured over the face, (taking care that the eyes are shut,) till it is a quarter of an inch thick. In a few minutes the plaster may be removed. In this a mould is to be formed, from which a second cast is to be taken, that will furnish casts exactly like the original. _Curious Experiment with a Glass of Water._ Saturate a certain quantity of water in a moderate heat, with three ounces of sugar; and when it will no longer receive that, there is still room in it for two ounces of salt of tartar, and after that for an ounce and a drachm of green vitriol, nearly six drachms of nitre, the same of sal-ammoniac, two drachms and a scruple of alum, and a drachm and half of borax. _To make Artificial Coruscations._ There is a method of producing artificial coruscations, or sparkling fiery meteors, which will be visible, not only in the dark but at noon-day, and that from two liquors actually cold. The method is this:--Fifteen grains of solid phosphorus are to be melted in about a drachm of water: when this is cold, pour upon it two ounces of oil of vitriol; let these be shaken together in a large phial, and they will at first heat, and afterwards will throw up fiery balls in great number, which will adhere like so many stars to the sides of the glass, and continue burning a considerable time; after this, if a small quantity of oil of turpentine be poured in without shaking the phial, the mixture will of itself take fire, and burn very furiously. The vessels should be large and open at the top. _Another Method._ Artificial coruscations may also be produced by means of oil of vitriol and iron, in the following manner:--Take a glass vessel capable of holding three quarts: put into this three ounces of oil of vitriol, and twelve ounces of water, then warming the mixture a little, throw in at several times two ounces, or more, of clear iron filings: upon this, an ebullition and white vapours will arise; then present a lighted candle to the mouth of the vessel, and the vapour will take fire, and afford a bright fulmination or flash; like lightning. Applying the candle in this manner several times, the effect will always be the same; and sometimes the fire will fill the whole body of the glass, and even circulate to the bottom of the liquor; at others, it will only reach a little down its neck. The great caution to be used in making this experiment, is the making the vapour of a proper heat; for if made too cold few vapours will arise; and, if made too hot, they will arise too fast, and will only take fire in the neck of the glass, without any remarkable coruscation. _To produce Fire from Cane._ The Chinese rattans, which are used, when split, for making cane chairs, will, when dry, if struck against each other, give fire; and are used accordingly in some places, in lieu of flint and steel. _To make an Eolian Harp._ This instrument may be made by almost any carpenter: it consists of a long narrow box of very thin deal, about five or six inches deep, with a circle in the middle of the upper side, of an inch and a half in diameter, in which are to be drilled small holes. On this side, seven, ten, or more strings, of very fine gut, are stretched over bridges at each end, like the bridges of a fiddle, and screwed up or relaxed with screw pins. The strings must be all tuned to one and the same note, and the instrument be placed in some current of air, where the wind can pass over its strings with freedom. A window, of which the width is exactly equal to the length of the harp, with the sash just raised to give the air admission, is a proper situation. When the air blows upon these strings, with different degrees of force, it will excite different tones of sounds; sometimes the blast brings out all the tones in full concert, and sometimes it sinks them to the softest murmurs. _To show the Pressure of the Atmosphere._ Invert a tall glass or jar in a dish of water, and place a lighted taper under it: as the taper consumes the air in the jar its pressure becomes less on the water immediately under the jar; while the pressure of the atmosphere on the water _without_ the circle of the jar remaining the same, part of the water in the dish will be forced up into the jar, to supply the place of the air which the taper has consumed. Nothing but the pressure of the atmosphere could thus cause part of the water to rise within the jar, above its own level. _Subaqueous Exhalation._ Pour a little clear water into a small glass tumbler, and put one or two small pieces of phosphoret of lime into it. In a short time, flashes of fire will dart from the surface of the water, and terminate in ringlets of smoke, which will ascend in regular succession. _Remarkable Properties in certain Plants._ Plants, when forced from their natural position, are endowed with a power to restore themselves. A hop-plant, twisting round a stick, directs its course from south to west, as the sun does. Untwist it, and tie it in the opposite direction, it dies. Leave it loose in the wrong direction, it recovers its natural direction in a single night. Twist a branch of a tree so as to invert its leaves, and fix it in that position; if left in any degree loose, it untwists itself gradually, till the leaves be restored to their natural position. What better can an animal do for its welfare? A root of a tree meeting with a ditch in its progress, is laid open to the air; what follows? It alters its course like a rational being, dips into the ground, surrounds the ditch, rises on the opposite side of its wonted distance from the surface, and then proceeds in its original direction. Lay a wet sponge near a root exposed to the air; the root will direct its course to the sponge; change the place of the sponge, the root varies its direction. Thrust a pole into the ground at a moderate distance from a climbing plant; the plant directs its course to the pole, lays hold of it, and rises on its natural height. A honeysuckle proceeds in its course, till it be too long for supporting its weight, and then strengthens itself by shooting into a spiral. If it meet with another plant of the same kind, they coalesce for mutual support; the one screwing to the right, the other to the left. If a honeysuckle twig meet with a dead branch, it screws from the right to the left. The claspers of briony shoot into the spiral, and lay hold of whatever comes in their way, for support. If, after completing a spiral of three rounds, they meet with nothing, they try again, by altering their course. _Flowers curiously affected by the Sun and the Weather._ The petals of many flowers expand in the sun, but contract all night, or on the approach of rain; after the seeds are fecundated the petals no longer contract. All the trefoil may serve as a barometer to the husbandman; they always contract their leaves on an impending storm. _Easy Method of obtaining Flowers of different Colours from the same Stem._ Scoop out the pith from a small twig of elder, and having split it lengthwise, fill each of the parts with small seeds that produce flowers of different colours, but that blossom nearly at the same time. Surround them with earth; and then tying together the two bits of wood, plant the whole in a pot filled with earth, properly prepared. _A Luminous Bottle, which will show the Hour on a Watch in the Dark._ Throw a bit of phosphorus, of the size of a pea, into a long glass phial, and pour boiling oil carefully over it, till the phial is one-third filled. The phial must be carefully corked, and when used should be unstopped, to admit the external air, and closed again. The empty space of the phial will then appear luminous, and give as much light as an ordinary lamp. Each time that the light disappears, on removing the stopper it will instantly re-appear. In cold weather the bottle should be warmed in the hands before the stopper is removed. A phial thus prepared may be used every night for six months. _To make Luminous Writing in the Dark._ Fix a small piece of solid phosphorus in a quill, and write with it upon paper; if the paper be carried into a dark room, the writing will appear beautifully luminous. _The Sublimated Tree._ Into a large glass jar inverted upon a flat brick tile, and containing near its top a branch of fresh rosemary, or any other such shrub, moistened with water, introduce a flat thick piece of heated iron, on which place some gum benzoin, in gross powder. The benzoin, in consequence of the heat, will be separated, and ascend in white fumes, which will at length condense, and form a most beautiful appearance upon the leaves of the vegetable. _Easy and curious Methods of foretelling Rainy or Fine Weather._ If a line be made of good whipcord, that is well dried, and a plummet affixed to the end of it, and then hung against a wainscot, and a line drawn under it, exactly where the plummet reaches, in very moderate weather it will be found to rise above it before rain, and to sink below when the weather is likely to become fair. But the best instrument of all, is a good pair of scales, in one of which let there be a brass weight of a pound, and in the other a pound of salt, or of saltpetre, well dried; a stand being placed under the scale, so as to hinder it falling too low. When it is inclined to rain, the salt will swell, and sink the scale: when the weather is growing fair, the brass weight will regain its ascendancy. _Contrivance for a Watch Lamp, perfectly safe, which will show the Hour of the Night, without any trouble, to a person lying in Bed._ It consists of a stand, with three claws, the pillar of which is made hollow, for the purpose of receiving a water candlestick of an inch diameter. On the top of the pillar, by means of two hinges and a bolt, is fixed on a small proportionate table, a box of six sides, lined with brass, tin, or any shining metal, nine inches deep, and six inches in diameter. In the centre of one of these sides is fixed a lens, double convex, of at least three inches and a half diameter. The centre of the side directly opposite to the lens is perforated so as to receive the dial-plate of the watch, the body of which is confined on the outside, by means of a hollow slide. When the box is lighted by a common watch-light, the figures are magnified nearly to the size of those of an ordinary clock. _Curious Experiment with a Tulip._ The bulb of a tulip in every respect resembles buds, except in their being produced under ground, and include the leaves and flower in miniature, which are to be expanded in the ensuing spring. By cautiously cutting in the early spring, through the concentric coats of a tulip root, longitudinally from the top to the base, and taking them off successively, the whole flower of the next summer's tulip is beautifully seen by the naked eye, with its petals, pistal, and stamina. _The Travelling of Sound experimentally proved._ There is probably no substance which is not in some measure a conductor of sound; but sound is much enfeebled by passing from one medium to another. If a man, stopping one of his ears with his finger, stop the other also by pressing it against the end of a long stick, and a watch be applied to the opposite end of the stick, or a piece of timber, be it ever so long, the beating of the watch will be distinctly heard; whereas, in the usual way, it can scarcely be heard at the distance of fifteen or eighteen feet. The same effect will take place if he stops both his ears with his hands, and rest his teeth, his temple, or the gristly part of one of his ears against the end of a stick. Instead of a watch, a gentle scratch may be made at one end of a pole or rod, and the person who keeps his ear in close contact with the other end of the pole, will hear it very plainly. Thus, persons who are dull of hearing, may, by applying their teeth to some part of a harpsichord, or other sounding body, hear the sound much better than otherwise. If a person tie a strip of flannel about a yard long, round a poker, then press with his thumbs and fingers the ends of the flannel into his ears, while he swings the poker against an iron fender, he will hear a sound very like that of a large church bell. _To produce Metallic Lead from the Powder._ Take one ounce of red lead, and half a drachm of charcoal in powder, incorporate them well in a mortar, and then fill the bowl of a tobacco-pipe with the mixture. Submit it to an intense heat, in a common fire, and when melted, pour it out upon a slab, and the result will be metallic lead completely revived. _To diversify the Colours of Flowers._ Fill a vessel of what size or shape you please, with good rich earth, which has been dried and sifted in the sun, then plant in the same a slip or branch of a plant bearing a white flower, (for such only can be tinged,) and use no other water to water it with, but such as is tinged with red, if you desire red flowers; with blue, if blue flowers, &c. With this coloured water, water the plant twice a day, morning and evening, and remove it into the house at night, so that it drink not of the morning or evening dew for three weeks. You will then experience, that it will produce flowers, not altogether tinctured with that colour wherewith you watered it, but partly with that, and partly with the natural. _How far Sound travels in a Minute._ However it may be with regard to the theories of sound, experience has taught us, that it travels at about the rate of 1142 feet in a second, or nearly thirteen miles in a minute. The method of calculating its progress is easily made known: when a gun is discharged at a distance, we see the fire long before we hear the sound; if, then, we know the distance of the place, and know the time of the interval between our first seeing the fire, and then hearing the report, this will show us exactly the time the sound has been travelling to us. For instance, if the gun be discharged a mile off, the moment the flash is seen I take a watch and count the seconds till I hear the sound; the number of seconds is the time the sound has been travelling a mile. _Easy Method of making a Rain Gauge._ A very simple rain gauge, and one which will answer all practical purposes, consists of a copper funnel the area of whose opening is exactly ten square inches: this funnel is fixed in a bottle, and the quantity of rain caught is ascertained by multiplying the weight in ounces by 173, which gives the depth in inches and parts of an inch. In fixing these gauges, care must be taken that the rain may have free access to them: hence the tops of buildings are usually the best places. When the quantities of rain collected in them at different places are compared, the instruments ought to be fixed at the same heights above the ground at both places, because at different heights the quantities are always different, even at the same place. _To make beautiful Transparent coloured Water._ The following liquors, which are coloured, being mixed, produce colours very different from their own. The yellow tincture of saffron, and the red tincture of roses, when mixed, produce a green. Blue tincture of violets, and brown spirit of sulphur, produce a crimson. Red tincture of roses, and brown spirits of hartshorn, make a blue. Blue tincture of violets, and blue solution of copper, give a violet colour. Blue tincture of cyanus, and blue spirit of sal-ammoniac coloured, make green. Blue solution of Hungarian vitriol, and brown ley of potash, make yellow. Blue solution of Hungarian vitriol, and red tincture of roses, make black; and blue tincture of cyanus, and green solution of copper, produce red. _Curious Experiment on Rays of Light._ That the rays of light flow in all directions from different bodies, without interrupting one another, is plain from the following experiment:--Make a little hole in a thin plate of metal, and set the plate upright on a table, facing a row of lighted candles standing near together; then place a sheet of paper or pasteboard at a little distance from the other side of the plate; and the rays of all the candles, flowing through the hole, will form as many specks of light on the paper as there are candles before the plate; each speck as distinct and large as if there were only one candle to cast one speck; which shows that the rays do not obstruct each other in their motions, although they all cross in the same hole. _The Power of Water._ Let a strong small iron tube of twenty feet in height be inserted into the bung-hole of a cask, and the aperture round so strongly closed, that it shall be water-tight; pour water into the cask till it is full, through the pipe; also continue filling the pipe till the cask bursts, which will be when the water is within a foot of the top of the tube. In this experiment the water, on bursting the vessel, will fly about with considerable violence. _The Pressure of Water._ The pressure of water may be known to every one who will only take the trouble to look at the cock of a water-butt when turned: if the tub or cistern be full, the water runs with much greater velocity through the cock, and a vessel will be filled from it in a shorter time than when it is only half-full, although the cock, in both cases, is equally replete with the fluid during the time the vessel is filling. From this also is understood, how a hole or leak, near the keel of a ship, admits the water much quicker, and with greater violence, than one of the same size near what the mariners call the water's edge. _Refraction of Light._ In the middle of an empty basin put a piece of money, and then retire from it till the edge of the basin hides the piece from your sight: then keep your head steady, let another person fill the basin gently with water; as the water rises in the basin the money will come in view; and when of a sufficient height in the basin, the whole of the piece will be in sight. _Wonderful Nature of Lightning._ If two persons, standing in a room, looking different ways, and a loud clap of thunder, accompanied with zigzag lightning, happen, they will both distinctly see the flash at the same time; not only the illumination, but the very form of the lightning itself, and every angle it makes in its course will be as distinctly perceptible, as though they had both looked directly at the cloud from whence it proceeded. If a person happened at that time to be looking on a book, or other object, which he held in his hand, he would distinctly see the form of the lightning between him and the object at which he looked. This property seems peculiar to lightning, as it does not apply to any other kind of fire whatever. _To show that the White of Eggs contains an Alkali._ Add to a wine-glass half full of tincture of red cabbage a small quantity of the white of an egg, either in a liquid state or rendered concrete by boiling. The tincture will lose its blue colour and become changed to green, because the white of the egg contains soda. _Two Inodorous Bodies become very Pungent and Odorous by Mixture._ When equal parts of muriate of ammonia and unslaked lime, both substances destitute of odour, are intimately blended together in a mortar, a very pungent gas (ammonia) becomes evolved. _Interesting Experiment for the Microscope._ The embryo grain of wheat, at the time of blossoming, being carefully taken out of the husk, will be found to have a small downy tuft at its extremity, which, when viewed in a microscope, greatly resembles the branches of thorn, spreading archwise, in opposite directions. By expanding a few of the grains, and selecting the most perfect, a very pretty microscopic object will be obtained for preservation. _The Travelling of Light._ Light travels at the rate of a hundred and fifty thousand miles in a single second; and it is seven minutes in passing from the sun to the earth, which is nearly a distance of seventy millions of miles. Such is the rapidity with which these rays dart themselves forward that a journey they thus perform in less than eight minutes, a ball from the mouth of a cannon would not complete in several weeks! But the minuteness of the particles of light are still several degrees beyond their velocity; and they are therefore harmless, because so very small. A ray of light is nothing more than a constant stream of minute parts, still flowing from the luminary, so inconceivably little, that a candle in a single second of time, has been said to diffuse several hundreds of millions more particles of light, than there could be grains in the whole earth, if it were entirely one heap of sand. The sun furnishes them, and the stars also, without appearing in the least to consume, by granting us the supply. Its light is diffused in a wide sphere, and seems inexhaustible. _Calculation of the Mass of Water contained in the Sea._ If we would have an idea of the enormous quantity of water which the sea contains, let us suppose a common and general depth of the ocean; by computing it at only 200 fathoms, or the tenth part of a mile, we shall see that there is sufficient water to cover the whole globe to the height of 503 feet of water; and if we were to reduce this water into one mass, we should find that it forms a globe of more than sixty thousand miles diameter. _Different Degrees of Heat imbibed from the Sun's Rays by Cloths of different Colours._ Walk but a quarter of an hour in your garden, when the sun shines, with a part of your dress white, and a part black; then apply your hand to them alternately, and you will find a very great difference in their warmth. The black will be quite hot to the touch, and the white still cool. Try to fire paper with a burning-glass; if it be white, you will not easily burn it; but if you bring the focus to a black spot, or upon letters, written or printed, the paper will immediately be on fire under the letters. Thus, fullers and dyers find black cloths, of equal thickness with white ones, and hung out equally wet, dry in the sun much sooner than the white, being more readily heated by the sun's rays. It is the same before a fire, the heat of which sooner penetrates black stockings than white ones, and so is apt sooner to burn a man's shins. Also beer much sooner warms in a black mug set before the fire than a white one, or in a bright silver tankard. Take a number of little square pieces of cloth from a tailor's pattern card, of various colours; say black, deep blue, lighter blue, green, purple, red, yellow, white, and other colours, or shades of colours; lay them all out upon the snow in a bright sun-shiny morning; in a few hours, the black being warmed most by the sun will be sunk so low as to be below the stroke of the sun's rays; the dark blue almost as low; the lighter blue not quite so much as the dark; the other colours less, as they are lighter; and the quite white remain on the surface of the snow, as it will not have entered it at all. _Alternate Illusion._ With a convex lens of about an inch focus, look attentively at a silver seal, on which a cipher is engraved. It will at first appear cut in, as to the naked eye; but if you continue to observe it some time, without changing your situation, it will seem to be in relief, and the lights and shades will appear the same as they did before. If you regard it with the same attention still longer, it will again appear to be engraved: and so on alternately. If you look off the seal for a few moments, when you view it again, instead of seeing it, as at first, engraved, it will appear in relief. If, while you are turned towards the light, you suddenly incline the seal, while you continue to regard it, those parts that seemed to be engraved will immediately appear in relief: and if, when you are regarding these seemingly prominent parts, you turn yourself so that the light may fall on the right hand, you will see the shadows on the same side from whence the light comes, which will appear not a little extraordinary. In like manner the shadows will appear on the left, if the light fall on that side. If instead of a seal you look at a piece of money, these alterations will not be visible, in whatever situation you place yourself. _Alarum._ Against the wall of a room, near the ceiling, fix a wheel of twelve or eighteen inches diameter; on the rim of which place a number of bells in tune, and, if you please, of different sizes. To the axis of this wheel there should be fixed a fly to regulate its motion; and round the circumference there must be wound a rope, to the end of which is hung a weight. Near to the wheel let a stand be fixed, on which is an upright piece that holds a balance or moveable lever, on one end of which rests the weight just mentioned; and to the other end must hang an inverted hollow cone, or funnel, the aperture of which is very small. This cone must be graduated on the inside, that the sand put in may answer to the number of hours it is to run. Against the upright piece, on the side next the cone, there must be fixed a check, to prevent it from descending. This stand, together with the wheel, may be enclosed in a case, and so contrived, as to be moved from one room to another with very little trouble. It is evident, from the construction of this machine, that when a certain quantity of the sand is run out, the weight will descend, and put the wheel in motion, which motion will continue till the weight comes to the ground. If the wheel be required to continue longer in motion, two or more pulleys may be added, over which the rope may run. _Musical Cascade._ Where there is a natural cascade, near the lower stream, but not in it, let there be placed a large wheel, equal to the breadth of the cascade: the diameter of this wheel, for about a foot from each end, must be much less than that of the middle part; and all the water from the cascade must be made to fall on the ends. The water that falls on the wheel may pass through pipes, so that part of it may be made occasionally to pass over or fall short of the wheel, as you would have the time of the music quicker or slower. The remaining part of the wheel, which is to be kept free from the water, must consist of bars, on which are placed stops that strike against the bells: these stops must likewise be moveable. It is evident from the construction of this machine, that the water falling on the floats at the end of the wheel, will make the stops, which are adapted to different tunes, strike the notes of those tunes on the respective bells. Two or three sets of bells may here be placed on the same line, when the cascade is sufficiently wide. Where there is not a natural cascade, one may be artificially constructed, by raising part of the ground, wherever there is a descent of water; whether it be a stream that supplies a reservoir or fountain, or serves domestic uses; or if it be refuse water that has already served some other purpose. _Writing on Glass by the Rays of the Sun._ Dissolve chalk in aqua fortis, to the consistence of milk, and add to that a strong solution of silver. Keep this liquor in a glass decanter well stopped. Then cut out from a paper the letters you would have appear, and paste the paper on the decanter, which you are to place in the sun, in such a manner that its rays may pass through the spaces cut out of the paper, and fall on the surface of the liquor. The part of the glass through which the rays pass will turn black, and that under the paper will remain white. You must observe not to move the bottle during the time of the operation. _To produce the Appearance of a Flower from its Ashes._ Make a tin box, with a cover that takes off. Let this box be supported by a pedestal of the same metal, and on which there is a little door. In the front of this box is to be a glass. In a groove, at a small distance from this glass, place a double glass, made in the same manner as described in p. 13, (_Magic Picture._) Between the front and back glasses place a small upright tin tube, supported by a cross piece. Let there be also a small chafing-dish placed in the pedestal. The box is to be opened behind. You privately place a flower in the tin tube, but not so near the front glass as to be in the least degree visible, and presenting one that resembles it to any person, desire him to burn it on the coals in a chafing-dish. You then strew some powder over the coals, which may be supposed to aid the ashes in producing the flower; and put the chafing-dish in the pedestal under the box. As the heat by degrees melts the composition between the glasses, the flower will gradually appear, but when the chafing-dish is taken away, and the powder of the ashes is supposed to be removed, the flower soon disappears. You may present several flowers, and let the person choose any one of them. In this case, while he is burning the flower, you fetch the box from another apartment, and at the same time put in a corresponding flower, which will make the experiment still more surprising. _Imitative Fire-works._ Take a paper that is blacked on both sides, or instead of black, the paper may be coloured on each side with a deep blue, which will be still better for such as are to be seen through transparent papers. It must be of a proper size for the figure you intend to exhibit. In this paper cut out with a penknife several spaces, and with a piercer make a number of holes, rather long than round, and at no regular distance from each other. To represent revolving pyramids and globes, the paper must be cut through with a penknife, and the space cut out between each spiral should be three or four times as wide as the spirals themselves. You must observe to cut them so that the pyramid or globe may appear to turn on its axis. The columns that are represented in pieces of architecture, or in jets of fire, must be cut in the same manner, if they are to be represented as turning on their axis. In like manner may be exhibited a great variety of ornaments, ciphers, and medallions, which, when properly coloured, cannot fail of producing the most pleasing effect. There should not be a very great diversity of colours, as they would not produce the most agreeable appearance. When these pieces are drawn on a large scale, the architecture or ornaments may be shaded; and, to represent different shades, pieces of coloured paper must be pasted over each other, which will produce an effect that would not be expected from transparent paintings. Five or six pieces of paper pasted over each other will be sufficient to represent the strongest shades. To give these pieces the different motions they require, you must first consider the nature of each piece; if, for example, you have cut out the figure of the sun, or of a star, you must construct a wire wheel of the same diameter with these pieces; over this wheel you paste a very thin paper, on which is drawn, with black ink, the spiral figure. The wheel thus prepared, is to be placed behind the sun or star, in such a manner that its axis may be exactly opposite the centre of either of these figures. This wheel may be turned by any method you think proper. Now, the wheel being placed directly behind the sun, for example, and very near to it, is to be turned regularly round, and strongly illuminated by candles placed behind it. The lines that form the spiral will then appear, through the spaces cut out from the sun, to proceed from its centre to its circumference, and will resemble sparks of fire that incessantly succeed each other. The same effect will be produced by the star or by any other figure where the fire is not to appear as proceeding from the circumference of the centre. These two pieces, as well as those that follow, may be of any size, provided you observe the proportion between the parts of the figure and the spiral, which must be wider in larger figures than in small. If the sun, for example, have from six to twelve inches diameter, the width of the strokes that form the spiral need not be more than one-twentieth part of an inch, and the spaces between them, that form transparent parts, about two-tenths of an inch. If the sun be two feet diameter, the strokes should be one-eighth of an inch, and the space between, one quarter of an inch; and if the figure be six feet diameter, the strokes should be one quarter of an inch and the spaces five-twelfths of an inch. These pieces have a pleasing effect, when represented of a small size, but the deception is more striking when they are of large dimensions. It will be proper to place those pieces, when of a small size, in a box quite closed on every side, that none of the light may be diffused in the chamber: for which purpose it will be convenient to have a tin door behind the box, to which the candlesticks may be soldered, and the candles more easily lighted. The several figures cut out should be placed in frames, that they may be put, alternately, in a groove in the forepart of the box; or there may be two grooves, that the second piece may be put in before the first is taken out. The wheel must be carefully concealed from the eye of the spectator. Where there is an opportunity of representing these artificial fires by a hole in the partition, they will doubtless have a much more striking effect, as the spectator cannot then conjecture by what means they are produced. It is easy to conceive that by extending this method, wheels may be constructed with three or four spirals, to which may be given different directions. It is manifest also that, on the same principle, a great variety of transparent figures may be contrived, and which may be all placed before the spiral lines. _To represent Cascades of Fire._ In cutting out cascades, you must take care to preserve a natural inequality in the parts cut out; for if, to save time, you should make all the holes with the same pointed tool, the uniformity of the parts will not fail to produce a disagreeable effect. As these cascades are very pleasing when well executed, so they are highly disgusting when imperfect. These are the most difficult pieces to cut out. To produce the apparent motion of these cascades, instead of drawing a spiral, you must have a slip of strong paper, of such length as you judge convenient. In this paper there must be a greater number of holes near each other, and made with pointed tools of different dimensions. At each end of the paper, a part of the same size with the cascade must be left uncut; and towards those parts the holes must be made at a greater distance from each other. When the cascade that is cut out is placed before the scroll of paper just mentioned, and it is entirely wound upon the roller, the part of the paper that is then between being quite opaque, no part of the cascade will be visible; but as the winch is gently turned, and regularly round, the transparent part of the paper will give to the cascade the appearance of fire that descends in the same direction; and the illusion will be so strong, that the spectators will think they see a cascade of fire; especially if the figure be judiciously cut out. _The Oracular Mirror._ Provide a round mirror of about three inches in diameter and whose frame is an inch wide. Line the under part of the frame, in which holes are to be cut, with very thin glass; behind this glass let a mirror of about two inches diameter be placed, which is to be moveable, so that by inclining the frame to either side, part of the mirror will be visible behind the glass on that side. Then take Spanish chalk, or cypress vitriol, of which you make a pencil, and with this you may write on a glass, and rub it off with a cloth, and by breathing on the glass, the writing will appear and disappear several times. With this pencil write on one side of the mirror, before it is put in the frame, the word _yes_, and on the other side, _no_; and wipe them off with a cloth. You propose to a person to ask any question of this mirror that can be answered by the words _yes_ or _no_. Then turning the glass to one side, and putting your mouth close to it, as if to repeat the question softly, you breathe on it, and the word yes or no will immediately appear. This mirror will serve for many other agreeable amusements. _The Hour of the Day or Night told by a suspended Shilling._ However improbable the following experiment may appear, it has been proved by repeated trials: Sling a shilling or sixpence at the end of a piece of thread by means of a loop. Then resting your elbow on a table, hold the other end of the thread betwixt your fore-finger and thumb, observing to let it pass across the ball of the thumb, and thus suspend the shilling into an empty goblet. Observe, your hand must be perfectly steady; and if you find it difficult to keep it in an immoveable posture, it is useless to attempt the experiment. Premising, however, that the shilling is properly suspended, you will observe, that when it has recovered its equilibrium, it will for a moment be stationary: it will then of its own accord, and without the least agency from the person holding it, assume the action of a pendulum, vibrating from side to side of the glass, and, after a few seconds, will strike the hour nearest to the time of day; for instance, if the time be twenty-five minutes past six, it will strike six; if thirty-five minutes past six, it will strike seven; and so on of any other hour. It is necessary to observe, that the thread should lie over the pulse of the thumb, and this may in some measure account for the _vibration_ of the shilling; but to what cause its striking the precise hour is to be traced, remains unexplained; for it is no less astonishing than true, that when it has struck the proper number, its vibration ceases, it acquires a kind of rotatory motion, and at last becomes stationary, as before. _Of Lightning, and the best Method of guarding against its mischievous Effects._ Experiments made in electricity first gave philosophers a suspicion, that the matter of lightning was the same with the electric matter. Experiments afterwards made on lightning obtained from the clouds by pointed rods, received into bottles, and subjected to every trial, have since proved this suspicion to be perfectly well founded; and that, whatever properties we find in electricity, are also the properties of lightning. This matter of lightning, or of electricity, is an extreme subtle fluid, penetrating other bodies, and subsisting in them, equally diffused. When, by any operation of art or nature, there happens to be a greater proportion of this fluid in one body than in another, the body which has most will communicate to that which has least, till the proportion becomes equal, provided the distance between them be not too great; or, if it be too great, till there be proper conductors to convey it from one to the other. If the communication be through the air, without any conductor, a bright light is seen between the bodies, and a sound is heard. In small experiments, we call this light and sound the electric spark and snap; but in the great operations of nature, the light is what we call _lightning_, and the sound (produced at the same time, though generally arriving later at our ears than the light does in our eyes) is, with its echoes, called _thunder_. If the communication of this fluid be by a conductor, it may be without either light or sound, the subtle fluid passing in the substance of the conductor. If the conductor be good, and of sufficient bigness, the fluid passes through it without hurting it. If otherwise, it is damaged or destroyed. All metals, and water, are good conductors. Other bodies may become conductors by having some quantity of water in them, as wood and other materials used in building, but not having much water in them, are not good conductors, and therefore are often damaged in the operation. Glass, wax, silk, wool, hair, feathers, and even wood perfectly dry, are non-conductors: that is, they resist instead of facilitating the passage of this subtle fluid. When this fluid has an opportunity of passing through two conductors, one good and sufficient, as of metal, the other not so good, it passes in the best, and will follow in any direction. The distance at which a body charged with this fluid will discharge itself suddenly, striking through the air into another body that is not charged, or not so highly charged, is different according to the quantity of the fluid, the dimensions and form of the bodies themselves, and the state of the air between them. This distance, whatever it happens to be between any two bodies, is called their striking _distance_, as, till they come within that distance of each other, no stroke will be made. The clouds have often more of this fluid in proportion than the earth: in which case, as soon as they come near enough, (that is, within the striking distance,) or meet with a conductor, the fluid quits them and strikes into the earth. A cloud fully charged with this fluid, if so high as to be beyond the striking distance from the earth, passes quietly without making noise or giving light, unless it meet with other clouds that have less. Tall trees and lofty buildings, as the towers and spires of churches, become sometimes conductors between the clouds and the earth; but, not being good ones, that is, not conveying the fluid freely, they are often damaged. Buildings that have their roofs covered with lead, or other metal, and spouts of metal continued from the roof into the ground to carry off the water, are never hurt by lightning, as, whenever it falls on such a building, it passes in the metals and not in the walls. When other buildings happen to be within the striking distance from such clouds, the fluid passes in the walls, whether of wood, brick, or stone, quitting the wall only when it can find better conductors near them, as metal rods, bolts, and hinges of windows or doors, gilding on wainscot, or frames of pictures, the silvering on the backs of looking-glasses, the wires for bells, and the bodies of animals, so containing watery fluids. And in passing through the house it follows the direction of these conductors, taking as many in its way as can assist in its passage, whether in a straight or crooked line, leaping from one to the other, if not far distant from each other, only rending the wall in the spaces where these partial good conductors are too distant from each other. An iron rod being placed on the outside of a building, from the highest part continued down into the moist earth, in any direction, straight or crooked, following the form of the roof or other parts of the building, will receive the lightning at its upper end, attracting it so as to prevent its striking any other part; and, affording it a good conveyance into the earth, will prevent its damaging any part of the building. A small quantity of metal is found able to conduct a quantity of this fluid. A wire no higher than a goose-quill has been known to conduct (with safety to the building, as far as the wire was continued) a quantity of lightning that did prodigious damage both above and below it; and probably larger rods are not necessary, though it is common in America to make them of half an inch, some three-quarters, or an inch, diameter. The rod may be fastened to the wall, chimney, &c., with staples of iron. The lightning will not leave the rod (a good conductor) to pass into the wall (a bad conductor) through those staples. It would rather, if any were in the wall, pass out of it into the rod, to get more readily by that conductor into the earth. If the building be very large and extensive, two or more rods may be placed in different parts, for greater security. Small ragged parts of clouds, suspended in the air between the great body of clouds and the earth, (like leaf gold in electrical experiments,) often serve as partial conductors for the lightning, which proceeds from one of them to another, and by their help comes within the striking distance to the earth or a building. It therefore strikes, through those conductors, a building that would otherwise be out of the striking distance. Long sharp points communicating with the earth, and presented to such parts of clouds, drawing silently from them the fluid they are charged with, they are then attracted to the cloud, and may leave the distance so great as to be beyond the reach of striking. It is therefore that we elevate the upper end of the rod, six or eight feet above the highest part of the building, tapering it gradually to a fine sharp point, which is gilt, to prevent its rusting. Thus the pointed rod either presents a stroke from the cloud, or if a stroke be made, conducts it to the earth, with safety to the building. The lower end of the rod should enter the earth so deep as to come at the moist part, perhaps two or three feet; and if bent when under the surface, so as to go in a horizontal line six or eight feet from the wall, and then bent again downwards three or four feet, it will prevent damage to any of the stones of the foundation. A person apprehensive of danger from lightning, happening during the time of thunder to be in a house not so secured, will do well to avoid sitting near the chimney, near a looking-glass, or any gilt pictures or wainscot; the safest place is in the middle of the room, (so it be not under a metal lustre suspended by a chain,) sitting in one chair and laying the feet up in another. It is still safer to bring two or three mattresses or beds into the middle of the room, and, folding them up double, place the chair upon them; for they, not being so good conductors as the walls, the lightning will not choose an interrupted course through the air of the room and the bedding, when it can go through a continued better conductor, the wall. But where it can be had, a hammock or swinging-bed, suspended by silk cords equally distant from the walls on every side, and from the ceiling and floor above and below, affords the safest situation a person can have in any room whatever; and what, indeed, may be deemed quite free from danger of any stroke by lightning. _The Leech, a Prognosticator of the Weather._ Confine a leech in a large phial, three parts filled with rain water, regularly changed twice a week, and placed on a window frame, fronting the north. In fair and frosty weather it lies motionless, and rolled up in a spiral form, at the bottom of the glass: but prior to rain or snow, it creeps up to the top, where if the rain will be heavy and of some continuance, it remains a considerable time; if trifling, it quickly descends. Should the rain or snow be accompanied with wind, it darts about its habitation with amazing celerity, and seldom ceases until it begins to blow hard. If a storm of thunder or lightning be approaching, it is exceedingly agitated, and expresses its feelings in violent convulsive starts, at the top of the glass. It is remarkable that however fine and serene the weather may be, and not the least indication to change, either from the sky, the barometer, or any other cause whatsoever, yet, if the animal ever shift its position, or move in a desultory manner, so certain will the coincident results occur, within thirty-six hours, frequently within twenty-four, and sometimes in twelve; though its motions chiefly depend on the fall and duration of the wet, and the strength of the wind. _The Awn of Barley an Hydrometer._ The awn of barley is furnished with stiff points, which, like the teeth of a saw, are all turned towards the point of it; as this long awn lies upon the ground, it extends itself in the moist air of night, and pushes forward the barley-corn, which it adheres to in the day; it shortens as it dries; and, as these points prevent it from receding, it draws up its pointed end, and thus, creeping like a worm, will travel many feet from the parent stem. That very ingenious mechanic philosopher, Mr. Edgworth, once made on this principle a wooden automaton: its back consisted of soft fir-wood, about an inch square, and four feet long, made of pieces cut the cross-way in respect to the fibres of the wood, and glued together; it had two feet before, and two behind, which supported the back horizontally, but were placed with their extremities, which were armed with sharp points of iron, bending backwards. Hence, in moist weather, the back lengthened, and the two foremost feet were pushed forwards; in dry weather the hinder feet were drawn after, as the obliquity of the points of the feet prevented it from receding. _The Power of Water when reduced to Vapour by Heat._ Whatever force water may have while its parts remain together, is nothing, if compared to the almost incredible power with which its parts are endued, when they are reduced to vapour by heat. Those steams which we see rising from the surface of boiling water, and which to us appear feeble, yet, if properly conducted, acquire immense force. In the same manner as gunpowder has but small effect, if suffered to expand at large, so the steam issuing from water is impotent, where it is permitted to evaporate into the air; but where confined in a narrow compass, as, for instance, where it rises in an iron tube shut up on every side, it there exerts all the wonders of its strength. _Muschenbrook_ has proved by experiment, that the force of gunpowder is feeble when compared to that of rising steam. A hundred and forty pounds of gunpowder blew up a weight of thirty thousand pounds: but, on the other hand, a hundred and forty pounds of water, converted by heat into steam, lifted a weight of seventy-seven thousand pounds; and would lift a much greater, if there were means of giving the steam more heat with safety; for the hotter the steam the greater is its force. _Artificial Memory._ In travelling along a road, the sight of the more remarkable scenes we meet with, frequently puts us in mind of the subjects we were thinking or talking of when we last saw them. Such facts, which were perfectly familiar, even to the vulgar, might very naturally suggest the possibility of assisting the memory, by establishing a connexion between the ideas we wish to remember, and certain sensible objects, which have been found from experience to make a permanent impression on the mind. It was said, that a person contrived a method of committing to memory the sermons which he was accustomed to hear, by fixing his attention, during the different heads of the discourse, on different compartments of the roof of the church, in such a manner as, that when he afterwards saw the roof, or remembered the order in which its compartments were disposed, he recollected the method which the preacher had observed in treating his subject. This contrivance was perfectly analogous to the topical memory of the ancients; an art which, whatever be the opinion we entertain of its use, is certainly entitled, in a high degree, to the praise of ingenuity. Suppose you fix in your memory the different apartments in some very large building, and that you had accustomed yourself to think of these apartments always in the same invariable order. Suppose further, that, in preparing yourself for a public discourse, in which you had occasion to treat of a great variety of particulars, you were anxious to fix in your memory the order you proposed to observe in the communication of your ideas. It is evident, that by a proper division of your subject into heads, and by connecting each head with a particular apartment, (which you could easily do, by conceiving yourself to be sitting in the apartment while you were studying the part of your discourse you mean to connect with it,) the habitual order in which these apartments occurred to your thoughts, would present to you in the proper arrangement, and without any effort on your part, the ideas of which you were to treat. It is also obvious, that very little practice would enable you to avail yourself of this contrivance, without any embarrassment or distraction of your attention. _To procure Hydrogen Gas._ Provide a phial with a cork stopper, through which is thrust a piece of tobacco-pipe. Into the phial put a few pieces of zinc, or small iron nails; on this pour a mixture, of equal parts of sulphuric acid (oil of vitriol) and water, previously mixed in a tea-cup, to prevent accidents. Replace the cork stopper, with a piece of tobacco-pipe in it; the hydrogen gas will then be liberated through the pipe into a small steam. Apply the flame of a candle or taper to this steam, and it will immediately take fire, and burn with a clear flame until all the hydrogen in the phial be exhausted. In this experiment the zinc or iron, by the action of the acid, becomes oxygenized, and is dissolved, thus taking the oxygen from the sulphuric acid and water; the hydrogen (the other constituent part of the water) is thereby liberated, and ascends. _To fill a Bladder with Hydrogen Gas._ Apply a bladder, previously wetted and compressed, in order to squeeze out all the common air, to the piece of tobacco-pipe inserted in the cork stopper of the phial, (as described in the experiment above.) The bladder will thus be filled with hydrogen gas. _Exploding Gas Bubbles._ Adapt the end of a common tobacco-pipe to a bladder filled with hydrogen gas, and dip the bowl of the pipe into soap-suds, prepared as if for blowing up soap bubbles; squeeze out small portions of gas from the bladder into the soap-suds, and the bubbles will ascend into the air with very great rapidity, until they are out of sight. If a lighted taper or candle be applied to the bubbles as they ascend from the bowl of the pipe, they will explode with a loud noise. _Another Method._ Put a small quantity of phosphorus and some potash, dissolved in water, into a retort; apply the flame of a candle or lamp to the bottom of the retort, until the contents boil. The phosphuretted hydrogen gas will then rise, and may be collected in receivers. But it, instead of receiving the gas into a jar, you let it simply ascend into water, the bubbles of gas will then explode in succession, as they reach the surface of the water, and a beautiful white smoke will be formed, which rises slowly and majestically to the ceiling. If bits of phosphorus are kept some hours in hydrogen gas, phosphorized hydrogen gas is produced: and if bubbles of this gas are thrown up into the receiver of an air-pump, previously filled with oxygen gas, a brilliant bluish flame will immediately fill the jar. _Singular Impression on the visual Nerves by a Luminous Object._ If, while sitting in a room, you look earnestly at the middle of a window, a little while, when the day is bright, and then shut your eyes, the figure of the window will still remain in your eye, and so distinct that you may count the panes. A remarkable circumstance attending this experiment is, that the impression of forms is better retained than that of colours; for, after the eyes are shut, when you first discern the image of the window, the panes appear dark, and the cross-bars of the sashes, with the window frames and walls, appear white and bright; but if you still add to the darkness of the eyes, by covering them with your hand, the reverse instantly takes place--the panes appear luminous, and the cross-bars dark; and by removing the hand, they are again reversed. _Curious Effects of Oil upon Water, and Water upon Oil._ Fasten a piece of pack-thread round a tumbler, with strings of the same from each side, meeting above it in a knot at about a foot distance from the top of the tumbler. Then putting in as much water as will fill about one-third part of the tumbler, lift it up by the knot, and swing it to and fro in the air; the water will keep its place as steadily in the glass as if it were ice. But pour gently in upon the water about as much oil, and then again swing it in the air as before, the tranquillity before possessed by the water will be transferred to the surface of the oil, and the water under it will be violently agitated. _Another curious Experiment with Oil and Water._ Drop a small quantity of oil into water agitated by the wind; it will immediately spread itself with surprising swiftness upon the surface, and the oil, though scarcely more than a tea-spoonful, will produce an instant calm over a space several yards square. It should be done on the windward side of the pond or river, and you will observe it extend to the size of nearly half an acre, making it appear as smooth as a looking-glass. One remarkable circumstance in this experiment is the sudden, wide, and forcible spreading of a drop of oil on the surface of the water; for if a drop of oil be put upon a highly polished marble table, or a looking-glass, laid horizontally, the drop remains in its place, spreading very little, but when dropped on water it spreads instantly many feet round, becoming so thin as to produce the prismatic colours for a considerable space, and beyond them so much thinner as to be invisible, except in its effect in smoothing the waves at a much greater distance. It seems as if a repulsion of its particles took place as soon as it touched the water, and so strong as to act on other bodies swimming on the surface, as straw, leaves, chips, &c., forcing them to recede every way from the drop, as from a centre, leaving a large clear space. _Remarkable Effects on the visual Nerves, by looking through differently-coloured Glasses._ After looking through green spectacles, the white paper of a book will, on first taking them off, appear to have a blush of red; and after looking through red glasses, a greenish cast. This seems to intimate a relation between green and red, not yet explained. _Weather Table._ --------------------+---------------------+------------------------ NEW AND FULL MOON. | SUMMER. | WINTER. --------------------+---------------------+------------------------ If the new or full | | moon enters into | | the first or last | | quarter of the | | hour of 12 at noon | Very rainy | Snow and rain. | | If between the | | hours of | | (P.M.) 2 and 4 | Changeable | Fair and mild. 4 and 6 | Fair | Fair. 6 and 8 | { Fair, if wind | { Fair and frosty, if | { at N.W. | { wind at N. or N.E. | { Rainy, if wind | { Rain or snow, if S. | { at S. or S.W. | { or S.W. 8 and 10 | Ditto | Ditto. 10 | Fair | Fair and frosty. (A.M.) 2 | Ditto | { Hard frost, unless | | { wind S.S.W. 2 and 4 | Cold, with frequent | | showers | 4 and 6 | Rain | Ditto, ditto. 6 and 8 | Wind and Rain | Stormy weather. 8 and 10 | Changeable | { Cold and rain, if | | { wind N.; snow if E. 10 and 12 | Frequent showers | Cold, with high wind. --------------------+---------------------+----------------------- A COMPLETE SYSTEM OF PYROTECHNY; OR THE ART OF MAKING FIRE-WORKS. In the art of making fire-works, great attention must be paid to the well-mixing of the materials--without which all labour is thrown away; to the purity of the articles; and to the proper quantities of each. Sulphur, to be good, must be of a high colour, and crack and bounce when held in the hand. For small fire-works, such as may be bought in the flour will be found quite good enough, but for the larger kinds, the lump brimstone ground is preferable. _Benzoin_ is used in fire-works, more for its pleasant scent than any material use for the purposes of fire. It may be procured at the chemists, ready for use. The oil is also used in wet composition, for stars, &c. _Of Sulphur, or Brimstone._ Sulphur is by nature the food of fire, and one of the principal ingredients in gunpowder, and in almost all compositions of fire-works; therefore, great care ought to be taken of its being good, and brought to the highest perfection. Now, to know when the sulphur is good, you are to observe that it be of a high yellow; and if, when held in one's hand, it crackles and bounces, it is a sign that it is fresh and good: but as the method of reducing brimstone to a powder is very troublesome, it is better to buy the flour ready made, which is done in large quantities, and in great perfection; but when a great quantity of fire-works is to be made, it is best to use the lump brimstone ground, in the same manner as gunpowder. _Of Saltpetre._ Saltpetre being the principal ingredient in fire-works, and a volatile body by reason of its aqueous and aërial parts, is easily rarefied by fire; but not so soon when foul and gross, as when purified from its gross and earthy parts, which greatly retard its velocity; therefore, when any quantity of fire-works is intended to be made, it would be necessary first to examine the saltpetre; for if it be not well cleansed from all impurities, and of a good sort, your works will not have their proper effect. _To pulverize Saltpetre._ Take a copper kettle, the bottom being spherical, and put into it fourteen pounds of refined saltpetre, with two quarts or five pints of clean water; then put the kettle on a slow fire, and when the saltpetre is dissolved, if any impurities arise, skim them off, and keep constantly stirring it with two large spatulas, till all the water exhales; and when done enough, it will appear like white sand, and as fine as flour; but if it should boil too fast, take the kettle off the fire, and set it on some wet sand, which will prevent the nitre from sticking to the kettle. When you have pulverized a quantity of saltpetre, be careful to keep it in a dry place. _To prepare Charcoal for Fire-works._ Charcoal is a preservative, by which the saltpetre and brimstone are made into gunpowder, by preventing the sulphur from suffocating the strong and windy exhalation of the nitre. There are several sorts of wood made use of for this purpose; some prefer hazel, others willow, and others alder. The method of burning the wood is this: cut it in pieces of two or three feet long, then slit each piece in four parts; scale off the bark and hard knots, and dry them in the sun, or in an oven; then make in the earth a square hole, and line it with bricks, in which lay the wood crossing one another, and set it on fire; when thoroughly lighted, and in a flame, cover the whole with boards, and fling earth over them close, to prevent the air from getting in, yet so as not to fall among the charcoal; and when it has lain thus for twenty-four hours, take out the coals and lay them in a dry place for use. It is to be observed, that charcoal for fire-works must always be soft and well burnt, which may be bought ready done. _Of Gunpowder, &c._ Gunpowder being a principal ingredient in fire-works, it will not be improper to give a short definition of its strange explosive force, and cause of action, which, according to Dr. Shaw's opinion of the chemical cause of the explosive force of gunpowder, is as follows:--"Each grain of gunpowder consisting of a certain proportion of sulphur, nitre, and coal, the coal presently taking fire, upon contact of the smallest spark; at which time both the sulphur and the nitre immediately melt, and by means of the coal interposed between them, burst into flame; which spreading from grain to grain, propagates the same effect almost instantaneously, whence the whole mass of powder comes to be fired; and as nitre contains a large proportion both of air and water, which are now violently rarefied by the heat, a kind of fiery explosive blast is thus produced, wherein the nitre seems, by its aqueous and aërial parts, to act as bellows to the other inflammable bodies (sulphur and coal) to blow them into a flame, and carry off their whole substance in smoke and vapour." _How to meal Gunpowder, Brimstone, and Charcoal._ There have been many methods used to grind these ingredients to a powder for fire-works, such as large mortars and pestles made of ebony, and other hard woods; but none of these methods have proved so effectual and speedy as the last invention, that of the mealing table. This table is made of elm, with a rim round its edge four or five inches high; and at the narrow end is a slider which runs in a groove and forms part of the rim; so that when you have taken out of the table as much powder as you conveniently can, with a copper shovel, you may sweep all clean out at the slider. When you are going to meal a quantity of powder, observe not to put too much on the table at once; but when you have put in a good proportion, take a muller and rub it therewith till all the grains are broken; sift it in a lawn sieve, that has a receiver and top to it; and that which does not pass through the sieve, return again to the table and grind it more, till you have brought it all fine enough to go through the sieve. Brimstone and charcoal are ground in the same manner as gunpowder, only the muller must be made of ebony, for these ingredients being harder than powder, would stick in the grain of the elm and be very difficult to grind; and as the brimstone is apt to stick and clog to the table, it would be best to keep one for that purpose only, by which means you will always have your brimstone clean and well ground. _Spur Fire._ This fire is the most beautiful of any composition yet known. As it requires great trouble to bring it to perfection, particular care must be paid to the following instructions. They are made generally in cases about six inches long, but not driven very hard. CHARGE. lb. oz. CHARGE. lb. oz. Saltpetre 4 0 } { Saltpetre 1 0 Sulphur 2 0 } or { Sulphur 0 8 Lamp-black 1 8 } { Lamp-black 4 quarts. This composition is very difficult to mix. The saltpetre and brimstone must be first sifted together, and then put into a marble mortar, and the lamp-black with them, which you work down by degrees with a wooden pestle, till all the ingredients appear of one colour, which will be something greyish, but very near black; then drive a little into a case for trial, and fire it in a dark place; and if the sparks, which are called stars or pinks, come out in clusters, and afterwards spread well without any other sparks, it is a sign of its being good, otherwise, not; for if any drossy sparks appear, and the stars not full, it is then not mixed enough; but if the pinks are very small, and soon break, it is a sign that you have rubbed it too much. This mixture, when rubbed too much, will be too fierce, and hardly show any stars; and, on the contrary, when not mixed enough, will be too weak, and throw out an obscure smoke, and lumps of dross, without any stars. The reason of this charge being called the spur fire is, because the sparks it yields have a great resemblance to the rowel of a spur, from whence it takes its name. As the beauty of this composition cannot be seen at so great a distance as brilliant fire, it has a better effect in a room than in the open air, and may be fired in a chamber without any danger; it is of so innocent a nature, that, although an improper phrase, it may be called a cold fire; and so extraordinary is the fire produced from this composition, that, if well made, the sparks will not burn a handkerchief when held in the midst of them; you may hold them in your hand while burning, with as much safety as a candle; and if you put your hand within a foot of the case, you will feel the sparks fall like drops of rain. _To make Touch Paper._ Dissolve in some spirits of wine or vinegar, a little saltpetre; then take some purple or blue paper, wet it with the above liquor, and when dry it will be fit for use. When you paste this paper on any of your works, take care that the paste does not touch that part which is to burn. The method of using this paper is, by cutting it into slips, long enough to go once round the mouth of the serpent, cracker, &c. When you paste on these slips, leave a little, above the mouth of the case, not pasted; then prime the case with meal-powder (see p. 165) and twist the paper to a point. _Of such Ingredients as show themselves in Sparks, when rammed into choked Cases._ The set colours of fire produced by sparks are divided into four sorts, viz., the black, white, grey, and red; the black charges are composed of two ingredients, which are meal-powder and charcoal; the white of three, viz., saltpetre, sulphur, and charcoal; the grey of four, viz., meal-powder, saltpetre, brimstone, and charcoal; and the red of three, viz., meal-powder, charcoal, and saw-dust. There are, besides these four regular or set charges, two others which are distinguished by the names of compound and brilliant charges; the compound charge being made of many ingredients, such as meal-powder, saltpetre, brimstone, charcoal, saw-dust, sea-coal, antimony, glass-dust, brass-dust, steel-filings, cast-iron, tanners' dust, &c., or any thing that will yield sparks; all which must be managed with discretion. The brilliant fires are composed of meal-powder, saltpetre, brimstone, and steel-dust; or with meal-powder, and steel-filings only. _Of the Method of mixing Compositions._ The performance of the principal part of fire-works depends much on the compositions being well mixed; therefore, great care ought to be taken in this part of the work, particularly in the composition for sky-rockets. When you have four or five pounds of ingredients to mix, which is a sufficient quantity at a time, (for a larger proportion will not do so well,) first put the different ingredients together, then work them about with your hands, till you think they are pretty well incorporated: after which, put them into a lawn sieve with a receiver and top to it; and if, after it is sifted, any should remain that will not pass through the sieve, grind it again till fine enough; and if it be twice sifted it will not be amiss; but the compositions for wheels and common works are not so material, nor need be so fine. But in all fixed works, from which the fire is to play regular, the ingredients must be very fine, and great care taken in mixing them well together: and observe, that, in all compositions wherein are steel or iron filings, the hands must not touch; nor will any works which have iron or steel in their charge, keep long in damp weather, without being properly prepared, according to the following directions:-- It may sometimes happen, that fire-works may be required to be kept a long time, or sent abroad; neither of which could be done with brilliant fires, if made with filings unprepared; for this reason, that the saltpetre being of a damp nature, it causes the iron to rust, the natural consequence of which is, that when the works are fired, there will appear but very few brilliant sparks, but instead of them a number of red and drossy sparks; and besides, the charge will be so much weakened, that if this should happen to wheels, the fire will not be strong enough to force them round; to prevent such accidents, prepare your filings after the following manner:--Melt in a glazed earthen pan some brimstone over a slow fire, and when melted, throw in some filings, which keep stirring about till they are covered with brimstone; this you must do while it is on the fire; then take it off, and stir it very quick till cold, when you must roll it on a board with a wooden roller, till you have broken it as fine as corn powder; after which, sift from it as much of the brimstone as you can. There is another method of preparing filings, so as to keep two or three months in winter; this may be done by rubbing them between the strongest sort of brown paper, which has been previously moistened with linseed oil. N.B. If the brimstone should take fire, you may put it out, by covering the pan close at top. It is not of much consequence what quantity of brimstone you use, provided there is enough to give each grain of iron a coat; but as much as will cover the bottom of a pan of about one foot diameter, will do for five or six pounds of filings. Cast-iron for gerbes will be preserved by the above method. _To make Crackers._ Cut some stout cartridge-paper into pieces three inches and a half broad, and one foot long; one edge of each of these pieces fold down lengthwise about three-quarters of an inch broad; then fold the double edge down a quarter of an inch, and turn the single edge back half over the double fold; open it, and lay all along the channel, which is formed by the foldings of the paper, some meal-powder; then fold it over and over till all the paper is doubled up, rubbing it down every turn; this being done, bend it backwards and forwards, two inches and a half or thereabouts, at a time, as often as the paper will allow; hold all these folds flat and close, and with a small pinching cord, give one turn round the middle of the cracker, and pinch it close; bind it with packthread, as tight as you can; then in the place where it was pinched, prime one end, and cap it with touch-paper. When these crackers are fired, they will give a report at every turn of the paper; if you would have a great number of bounces, you must cut the paper longer, or join them after they are made; but if they are made very long before they are pinched, you must have a piece of wood with a groove in it, deep enough to let in half the cracker; this will hold it straight while it is pinching. _To make Squibs and Serpents._ First make the cases, of about six inches in length, by rolling slips of stout cartridge-paper three times round a roller, and pasting the last fold; tying it near the bottom as tight as possible, and making it air-tight at the end, by sealing-wax. Then take of gunpowder half a pound, charcoal one ounce, brimstone one ounce, and steel-filings half an ounce, (or in like proportion,) grind them with a muller, or pound them in a mortar. Your cases being dry and ready, first put a thimble-full of your powder, and ram it hard down with a ruler; then fill the case to the top with the aforesaid mixture, ramming it hard down in the course of filling, two or three times; when this is done point with touch-paper, which should be pasted on that part which touches the case, otherwise it is liable to drop off. _Sky-Rockets._ Rockets being of the fire-works most in use, we shall give them the preference in description. As the performance of rockets depends much upon their moulds, they should be made according to the following proportions:--Taking the diameter of the orifice, its height should be equal to six diameters and two-thirds: the choke, one diameter and one-third of this model, will serve for every rocket from 4 oz. to 6 lb.--For instance:--suppose the diameter of a rocket of 1 lb. be 1-1/2 inch, then its length being 6 diameters and two-thirds, the length of the case must be 10-1/3 inches, and the choke 2-1/4 inches. Your rammer must have a collar of brass, to prevent the wood from splitting. _Method of rolling Rocket Cases._--The cases must be made of the strongest cartridge-paper, and rolled dry. The case of a middling-sized rocket will take up paper of four or five sheets thick; having cut your papers to a proper size, and the last sheet with a slope at one end, fold down one end, and lay your former on the double edge, and when you have rolled on the paper within two or three turns, lay the next sheet on that part which is loose, and roll it all on. Then, in order to roll the case as hard as possible, place it on a table, and with a smooth board roll it for some time forwards on the table, till it becomes quite hard and firm. This must be done with every sheet. You have next to choke the case; for which purpose draw your former a little distance from the bottom, then, with a cord, once round the case, pull it rather easy at first, and harder, till you have closed the end. To make it easy, you may dip the ends of the inner sheets in water before rolling, then bind it with small twine. Having thus pinched and tied the case so as not to give way, put it into the mould without its foot, and with a mallet drive the former hard on the end-piece, which will force the neck close and smooth. This done, cut the case to its proper length, allowing from the neck to the edge of the mouth half a diameter, which is equal to the height of the nipple; then take out the former, and drive the case over the piercer with a long rammer, and the vent will be of a proper size. Having formed your cases, we will now proceed to the description of the ingredients necessary for the rocket. _Of mixing the Composition._--The performance of the principal part of fire-works depends much on the compositions being well mixed; therefore, great care must be taken in this part of the work, particularly for the composition for sky-rockets. When you have four or five pounds of ingredients to mix, which is a sufficient quantity at a time, (for a large proportion will not do so well,) first put the different ingredients together, then work them about with your hands, till you think they are pretty well incorporated; after which, put them into a lawn sieve with a receiver and top to it; and if, after it is sifted, any remains that will not pass through the sieve, grind it again till it is fine enough; and if it be twice sifted it will not be amiss; but the compositions for wheels and common works are not so material, nor need be so fine. But in all fixed works, from which the fire is to play regular, the ingredients must be very fine, and great care taken in mixing them well together; and observe, that in all compositions wherein are iron filings, the hand must not touch them; nor will any works which have iron or steel in their charge keep long in damp weather. _To drive or ram Rockets._--Rockets are filled hollow, otherwise they would not ascend, and there is not a part that requires greater attention than this stage of the process. One blow more or less with the mallet will spoil the ascent. The charge of rockets must always be driven above the piercer, and on it must be rammed a thin head of clay; through the middle of which bore a small hole to the composition, that when the charge is burnt to the top, it may communicate its fire through the hole to the stars in the head. To a rocket of four ounces, give to each ladle-full of charge 16 strokes; to a rocket of 1 lb., 28; to a 2-pounder, 36; to a 4-pounder, 42; and to a 6-pounder, 56; but rockets of a larger sort cannot be driven well by hand, but must be rammed with a machine made in the same manner as those for driving piles. The method of ramming wheel cases, or any other sort in which the charge is driven solid, is the same as sky-rockets. When you load the heads of your rockets with stars, rains, serpents, crackers, scrolls, or any thing else, according to your fancy, remember always to put a ladle-full of meal-powder into each head, which will be enough to burst the head and disperse the stars, or whatever it contains. _Decorations for Sky-rockets._--Sky-rockets may be decorated according to fancy. Some are headed with stars of different sorts, such as tailed, brilliant, white, blue, and yellow stars, &c. Some with gold and silver rains; others with serpents, crackers, fire-scrolls, and marrons; and some with small rockets and other devices, as the maker pleases. LENGTH OF ROCKET-STICKS. For rockets of 6 lb. 0 oz. the stick must be 14 ft. 10 in. long 4 0 12 10 2 0 9 4 1 0 8 2 0 8 6 6 0 4 5 3 Having your sticks ready, cut on one of the flat sides at the top a groove the length of the rocket, and as broad as the stick will allow; then on the opposite flat side cut two notches, for the cord which ties on the rocket to lie in; one of these notches must be near the top of the stick, and the other facing the neck of the rocket; the distance between these notches may be easily known, for the top of the stick should always touch the head of the rocket. When your rockets and sticks are ready, lay the rockets in the grooves in the sticks, and tie them on. We will now proceed to the charge for sky-rockets. ROCKETS OF FOUR OUNCES. lb. oz. Meal-powder 1 4 Saltpetre 0 4 Charcoal 0 2 ROCKETS OF EIGHT OUNCES. lb. oz. Meal-powder 1 0 Saltpetre 0 4 Brimstone 0 3 Charcoal 0 1-1/2 ONE POUND. lb. oz. Meal-powder 2 0 Saltpetre 0 8 Brimstone 0 4 Charcoal 0 2 Steel-filings 0 1-1/2 SKY-ROCKETS IN GENERAL. lb. oz. Saltpetre 4 0 Brimstone 1-1/2 0 Charcoal 1 12 Meal-powder 0 2 LARGE SKY-ROCKETS. lb. oz. Saltpetre 4 0 Meal-powder 1 0 Brimstone 1 0 ROCKETS OF A MIDDLING SIZE. lb. oz. Meal-powder 1 0 Charcoal 1 0 Saltpetre 3 0 Sulphur 2 0 ROCKET STARS. WHITE STARS. lb. oz. Meal-powder 0 4 Saltpetre 0 12 Sulphur vivum 0 6 Oil of spike 0 2 Camphor 0 5 BLUE STARS. lb. oz. Meal-powder 0 8 Saltpetre 0 4 Sulphur 0 2 Spirits of wine 0 2 Oil of Spike 0 2 VARIEGATED STARS. lb. oz. Meal-powder 0 3-1/2 Saltpetre 0 4 Sulphur vivum 0 2 Camphor 0 2 BRILLIANT STARS. lb. oz. Saltpetre 0 8-1/2 Sulphur 0 1-1/2 Meal-powder 0 0-3/4 Worked up with spirits of wine only. COMMON STARS. lb. oz. Saltpetre 1 0 Brimstone 0 4 Antimony 0 4-3/4 Isinglass 0 0-1/2 Camphor 0 0-1/4 Spirits of wine 0 0-1/4 TAILED STARS. lb. oz. Meal-powder 0 2 Brimstone 0 2 Saltpetre 0 2 Charcoal (coarsely ground) 0 0-3/4 STARS OF A FINE COLOUR. lb. oz. Sulphur 0 1 Meal-powder 0 1 Saltpetre 0 1 Camphor 0 0-1/4 Oil of turpentine 0 0-1/4 RAINS. GOLD RAIN FOR SKY-ROCKETS. lb. oz. Saltpetre 0 8 Brimstone 0 2 Glass-dust 0 1 Antimony 0 0-3/4 Brass-dust 0 0-1/4 Saw-dust 0 0-1/4 SILVER RAIN. lb. oz. Saltpetre 0 8 Brimstone 0 2 Charcoal 0 4 Steel-dust 0 0-1/4 _To fix one Rocket on the top of another._--When sky-rockets are fixed one on the top of another, they are called _towering rockets_, on account of their mounting so very high. Towering rockets are made after this manner: Fix on a pound rocket a head without a collar; then take a four-ounce rocket, which may be headed or bounced, and rub the mouth of it with meal-powder wetted with spirit of wine: this done, put it in the head of a large rocket with its mouth downwards; but before it is put in, stick a bit of quick-match in the hole of the clay of the pound rocket, which match should be long enough to go a little way up the bore of the small rocket, to fire it when the large rocket is burnt out. As the four-ounce rocket is too small to fill the head of the other, roll round it as much tow as will make it stand upright in the centre of the head: the rocket being thus fixed, paste a single paper round the opening of the top of the head of the large rocket. The large rocket must have only half a diameter of charge rammed above the piercer; for, if filled to the usual height, it would turn before the small one takes fire, and entirely destroy the intended effect: when one rocket is headed with another, there will be no occasion for any blowing powder; for the force with which it goes off will be sufficient to disengage it from the head of the first fired rocket. The sticks for these rockets must be a little longer than for those headed with stars, rains, &c. _Caduceous Rockets._--They are such as, in rising, form two spiral lines, by reason of their being placed obliquely, one opposite to the other; and their counterpoise in the centre, which causes them to rise in a vertical direction. Rockets for this purpose must have their ends choked close, without either head or bounce; for a weight at the top would be a great obstruction to their mounting. No caduceous rockets ascend so high as single, because of their serpentine motion, and likewise the resistance of air, which is much greater than two rockets of the same size would meet with if fired singly. The sticks for this purpose must have all their sides equal, and the sides should be equal to the breadth of a stick proper for a sky-rocket of the same weight as those you intend to use, and made to taper downwards as usual, long enough to balance them, one length of a rocket from the cross stick, which must be placed from the large stick six diameters of one of the rockets, and its length seven diameters; so that each rocket, when tied on, may form, with the large stick, an angle of 60 degrees. In tying on the rockets, place their heads on the opposite side of the cross stick; then carry a leader from the mouth of one into that of the other. When these rockets are to be fired, suspend them between two hooks, or nails, then burn the leader through the middle, and both will take fire at the same time. Rockets of 1 lb. are a good size for this use. _Honorary Rockets._--These are the same as sky-rockets, except that they carry no head nor report, but are closed at top, on which is fixed a cone; then on the case, close to the top of the stick, is tied on a two-ounce case, about five or six inches long, filled with a strong charge, and pinched close at both ends; then in the reverse side, at each end, bore a hole in the same manner as in tourbillons, to be presently described; from each hole carry a leader into the top of the rocket. When the rocket is fired, and arrived to its proper height, it will give fire to the case at top; which will cause both rocket and stick to spin very fast in their return, and represent a worm of fire descending to the ground. There is another method of placing the small case, which is by letting the stick rise a little above the top of the rocket, and tying the case to it, so as to rest on the rocket: these rockets have no cones. A third method by which they are managed is this: in the top of a rocket fix a piece of wood, in which drive a small iron spindle; then make a hole in the middle of the small case, through which is put the spindle; then fix on the top of it a nut, to keep the case from falling off; when this is done, the case will turn very fast, without the rocket: but this method does not answer so well as either of the former. _To make a Rocket form an Arch in rising._--Having some rockets made, headed according to fancy, and tied on their sticks, get some sheet tin, and cut it into round pieces about three or four inches diameter; then on the stick of each rocket, under the mouth of the case, fix one of these pieces of tin 16 inches from the rocket's neck, and support it by a wooden bracket, as strong as possible: the use of this is, that when the rocket is ascending, the fire may play with greater force on the tin, which will divide the tail in such a manner that it will form an arch as it mounts, and will have a very good effect when well managed; if there is a short piece of port fire, of a strong charge, tied to the end of the stick, it will make a great addition; but this must be lighted before the rocket is fired. _To make several Rockets rise together._--Take six, or any number of sky-rockets, of any size; then cut some strong packthread into pieces of three or four yards long, and tie each end of these pieces to a rocket in this manner: Having tied one end of the packthread round the body of one rocket, and the other end to another, take a second piece of packthread, and make one end of it fast to one of the rockets already tied, and the other end to a third rocket, so that all the rockets, except the two on the outside, will be fastened to the two pieces of packthread: the length of thread from one rocket to the other may be what the maker pleases; but the rockets must be all of a size, and their heads filled with the same weight of stars, rains, &c. Having thus done, fix in the mouth of each rocket a leader of the same length; and when about to fire them, hang them almost close; then tie the ends of the leaders together, and prime them; this prime being fired, all the rockets will mount at the same time, and divide as far as the strings will allow; and this division they keep, provided they are all rammed alike, and well made. They are sometimes called chained rockets. _To fix several Rockets to the same Stick._--Two, three, or six sky-rockets, fixed on one stick, and fired together, make a grand and beautiful appearance; for the tails of all will seem but as one of an immense size, and the breaking of so many heads at once will resemble the bursting of an air-balloon. The management of this device requires a skilful hand; but if the following instructions be well observed, even by those who have not made a great progress in this art, there will be no doubt of the rockets having the desired effect. Rockets for this purpose must be made with the greatest exactness, all rammed by the same hand, in the same mould, and filled with the same proportion of composition: and after they are filled and headed, must all be of the same weight. The stick must also be well made (and proportioned) to the following directions; first, supposing the rockets to be half-pounders, whose sticks are six feet six inches long, then if two, three, or six of these are to be fixed on one stick, let the length of it be nine feet nine inches; then cut the top of it into as many sides as there are rockets, and let the length of each side be equal to the length of one of the rockets without its head; and in each side cut a groove (as usual;) then from the grooves plane it round, down to the bottom, where its thickness must be equal to half the top of the round part. As their thickness cannot be exactly ascertained, we shall give a rule, which generally answers for any number of rockets above two; the rule is this: that the stick at top must be thick enough, when the grooves are cut, for all the rockets to lie, without pressing each other, though as near as possible. When only two rockets are to be fixed on one stick, let the length of the stick be the last given proportion, but shaped after the common method, and the breadth and thickness double the usual dimensions. The point of poise must be in the usual place (let the number of rockets be what it will;) if sticks made by the above directions should be too heavy, plane them thinner; and if too light, make them thicker; but always make them of the same length. When more than two rockets are tied on one stick, there will be some danger of their flying up without the stick, unless the following precaution is taken: For cases being placed on all sides, there can be no notches for the cord which ties on the rockets to lie in: therefore, instead of notches, drive a small nail in each side of the stick, between the necks of the cases, and let the cord, which goes round their necks, be brought close under the nails; by this means the rockets will be as secure as when tied on singly. The rockets being thus fixed, carry a quick-match, without a pipe, from the mouth of one rocket to the other; this match being lighted will give fire to all at once. Though the directions already given may be sufficient for these rockets, we shall here add an improvement on a very essential part of this device, which is, that of hanging the rockets to be fired; for before the following method was contrived, many attempts proved unsuccessful. Instead, therefore, of the old and common manner of hanging them on nails or hooks, make use of the following contrivance: Have a ring made of strong iron wire, large enough for the stick to go in as far as the mouths of the rockets; then have another ring supported by a small iron, at some distance from the post or stand to which it is fixed; then have another ring fit to receive and guide the small end of the stick. Rockets thus suspended will have nothing to obstruct their fire; but when they are hung on nails or hooks, in such a manner that some of their mouths or against or upon a rail, there can be no certainty of their rising in a vertical direction. _To fire Rockets without Sticks._--You must have a stand, of a block of wood, a foot diameter, and make the bottom flat, so that it may stand steady: in the centre of the top of this block draw a circle two inches and a half diameter, and divide the circumference of it into three equal parts; then take three pieces of thick iron wire, each about three feet long, and drive them into the block, one at each point made on the circle; when these wires are driven in deep enough to hold them fast and upright, so that the distance from one to the other is the same at top as at bottom, the stand is complete. The stand being thus made, prepare the rockets thus: Take some common sky-rockets of any size, and head them as you please; then get some balls of lead, and tie to each a small wire two or two feet and a half long, and the other end of each wire tie to the neck of a rocket. These balls answer the purpose of sticks, when made of a proper weight, which is about two-thirds the weight of the rocket; but when they are of a proper size, they will balance the rocket in the same manner as a stick, at the usual point of poise. To fire these, hand them one at a time, between the tops of the wires, letting their heads rest on the point of the wires, and the balls hang down between them: if the wires should be too wide for the rockets, press them together till they fit; and if too close, force them open; the wires for this purpose must be softened, so as not to have any spring, or they will not keep their position when pressed close or opened. _Scrolls for Rockets._--Cases for scrolls should be made four or five inches in length, and their interior diameters three-eighths of an inch: one end of these cases must be pinched quite close before beginning to fill; and when filled, close the other end; then in the opposite sides make a small hole at each end, to the composition, as in tourbillons, and prime them with wet meal-powder. You may put in the head of the rocket as many of these cases as it will contain: being fired, they turn very quick in the air, and form a scroll or spiral line. They are generally filled with a strong charge, as that of serpents or brilliant fire. _Stands for Rockets._--Care must be taken, in placing the rockets, when they are to be fired, to give them a vertical direction at their first setting out; which may be managed thus: Have two rails of wood, of any length, supported at each end by a perpendicular leg, so that the rails may be horizontal, and let the distance from one to the other be almost equal to the length of the sticks of the rockets intended to be fired; then in the front of the top rail drive square hooks at eight inches distance, with their points turned sidewise, so that when the rockets are hung on them, the points will be before the sticks, and keep them from falling or being blown off by the wind; in the front of the rail at bottom must be staples, driven perpendicularly under the hooks at top; through these staples put the small ends of the rocket-sticks. Rockets are fired by applying a lighted port-fire to their mouths. _Table-Rockets._--Table-rockets are designed merely to show the truth of driving, and the judgment of a fire-worker; they having no other effect, when fired, than spinning round in the same place where they began, till they are burnt out, and showing nothing more than a horizontal circle of fire. The method of making these rockets is thus:--Have a cone turned out of hard wood two inches and a half in diameter, and as much high; round the base of it drive a line; on this line fix four spokes, each two inches long, so as to stand one opposite the other; then fill four nine-inch one-pound cases with any strong composition, within two inches of the top: these cases are made like tourbillons, and must be rammed with the greatest exactness. The rockets being filled, fix their open ends on the short spokes; then in the side of each case bore a hole near the clay; all these holes, or vents, must be so made that the fire of each case may act the same way; from these vents carry leaders to the top of the cone, and tie them together. When the rockets are to be fired, set them on a smooth table, and light the leaders in the middle, and all the cases will fire together and spin on the point of the cone. These rockets may be made to rise like tourbillons, by making the cases shorter, and boring four holes in the under side of each at equal distances; this being done they are called _double tourbillons_. _Note._--All the vents in the under side of the cases must be lighted at once, and the sharp point of the cone cut off; at which place make it spherical. WHEELS. Wheel-cases are made to any length; which must always depend on the size of the wheel, but must not exceed the length of each angle. Charge for wheel-cases, from 2 oz. to 4 lb. lb. oz. Meal-powder 4 0 Saltpetre 1 0 Brimstone 0 8 Charcoal 0 4 The filings in this composition may be varied by using a portion of sea-coal, glass-dust, saw-dust, &c., or a combination of the whole. SLOW FIRE FOR WHEELS. lb. oz. Saltpetre 0 4 Brimstone 0 2 Meal-powder 0 1-1/2 or, 1 oz. of brimstone may be used with 1 oz. of antimony. DEAD FIRE FOR WHEELS. oz. dr. Saltpetre 4-1/4 0 Brimstone 0-1/4 0 Lapis-caliminaris 0 2 Antimony 0 2 _Single Vertical Wheels._--There are different sorts of vertical wheels; some having their fells of a circular form, others of an hexagonal, octagonal, or decagonal form, or of any number of sides, according to the length of the cases you design for the wheel; the spokes being fixed in the nave, nail slips of tin, with their edges turned up so as to form grooves for the cases to lie in; form the end of one spoke to that of another; then tie the cases in the grooves head to tail, in the same manner as those on the horizontal water-wheel; so that the cases, successively taking fire from one another, will keep the wheel in an equal rotation. Two of these wheels are very often fired together, one on each side of a building, and both lighted at the same time, and all the cases filled alike, to make them keep time together; as they will, if made by the following directions: In all the cases of both wheels, except the first, on each wheel drive two or three ladlesful of slow fire, in any part of the case; but be careful to ram the same quantity in each case; and in the end of one of the cases, on each wheel, you may ram one ladleful of dead-fire composition, which must be very lightly driven; you may also make many changes of fire by this method. Let the hole in the nave of the wheel be lined with brass, and made to turn on a smooth iron spindle. On the end of this spindle let there be a nut, to screw off and on; when you have put the wheel on the spindle, screw on the nut, which will keep the wheel from flying off. Let the mouth of the first case be a little raised. Vertical wheels are made from ten inches to three feet diameter, and the size of the cases must differ accordingly; four-ounce cases will do for wheels of 14 or 16 inches diameter, which is the proportion generally used. The best wood for wheels of all sorts is a light and dry beech. _Horizontal Wheels._--They are best when their fells are made circular; in the middle of the top of the nave must be a pintle, turned out of the same piece as the nave, two inches long, and equal in diameter to the bore of one of the cases of the wheel; there must be a hole bored up the centre of the nave, within half an inch of the top of the pintle. The wheel being made; nail at the end of each spoke (of which there should be six or eight) a piece of wood, with a groove cut in it to receive the case. Fix these pieces in such a manner that half the cases may incline upwards and half downwards, and that, when they are tied on, their heads and tails may come very nearly together: from the tail of one case to the mouth of the other carry a leader, which should be secured with pasted paper. Besides these pipes, it will be necessary to put a little meal-powder within the pasted paper, to blow off the pipe, that there may be no obstruction to the fire from the cases. By means of these pipes the cases will successively take fire, burning one upwards and the other downwards. On the pintle fix a case of the same sort as those on the wheel; this case must be fired by a leader from the mouth of the last case on the wheel, which case must play downwards: instead of a common case in the middle, you may put a case of Chinese fire, long enough to burn as long as two or three of the cases on the wheel. Horizontal wheels are often fired two at a time, and made to keep time like vertical wheels, only they are made without any slow or dead fire; 10 or 12 inches will be enough for the diameter of wheels with six spokes. _Spiral Wheels._--They are only double horizontal wheels, and made thus: the nave must be about six inches long, and rather thicker than the single sort; instead of the pintle at top, make a hole for the case to be fixed in, and two sets of spokes, one set near the top of the nave, and the other near the bottom. At the end of each spoke cut a groove wherein you tie the cases, there being no fell: the spokes should not be more than two inches and a half long from the naves, so that the wheel may not be more than eight or nine inches diameter; the cases are placed in such a manner, that those at top play down, and those at bottom play up; but let the third or fourth case play horizontally. The case in the middle may begin with any of the others; six spokes will be enough for each set, so that the wheel may consist of 12 cases, besides that on the top: the cases six inches each. _Plural Wheels._--Plural wheels are made to turn horizontally, and to consist of three sets of spokes, placed six at top, six at bottom, and four in the middle; which last must be a little shorter than the rest: let the diameter of the wheel be 10 inches: the cases must be tied on the ends of the spokes in grooves cut on purpose, or on pieces of wood nailed on the ends of the spokes, with grooves cut in them as usual: in clothing these wheels, make the upper set of cases play obliquely downwards, the bottom set obliquely upwards, and the middle set horizontally. In placing the leaders, they must be managed so that the cases may burn thus, viz., first up, then down, then horizontal, and so on with the rest. But another change may be made, by driving in the end of the eighth case two or three ladlesful of slow fire, to burn till the wheel has stopped its course; then let the other cases be fixed the contrary way, which will make the wheel run back again; for the case at top you may put a small gerbe; and let the cases on the spokes be short, and filled with a strong brilliant charge. _Illuminated Spiral Wheel._--First have a circular horizontal wheel made two feet diameter, with a hole quite through the nave; then take three thin pieces of deal, three feet long each, and three-fourths of an inch broad each: nail one end of each of these pieces to the fell of the wheel, at an equal distance from one another, and the other end nail to a block with a hole in its bottom, which must be perpendicular to that in the block of the wheel, but not so large. The wheel being thus made, have a loop planed down very thin and flat; then nail one end of it into the fell of the wheel, and wind it round the three sticks in a spiral line from the wheel to the block at top; on the top of this block fix a case of Chinese fire; on the wheel you may place any number of cases, which must incline downwards, and burn two at a time. If the wheel should consist of ten cases, you may let the illuminations and Chinese fire begin with the second cases. The spindle for this wheel must be a little longer than the cone, and made very smooth at top, on which the upper block is to turn, and the whole weight of the wheel to rest. _Double Spiral Wheels._--For these wheels, the block or nave must be as long as the height of the worms, or spiral lines, but must be made very thin, and as light as possible. In this block must be fixed several spokes, which must diminish in length, from the wheel to the top, so as not to exceed the surface of a cone of the same height. To the ends of these spokes nail the worms, which must cross each other several times: close these worms with illuminations, the same as those on the single wheels; but the horizontal wheel you may clothe as you like. At the top of the worm place a case of spur-fire, or an amber light. _Balloon Wheels._--They are made to turn horizontally: they must be made two feet diameter, without any spokes, and very strong, with any number of sides. On the top of a wheel range and fix in pots, three inches diameter and seven inches high each, as many of these as there are cases on the wheel: near the bottom of each pot make a small vent; into each of these vents carry a leader from the tail of each case; load some of the pots with stars, and some with serpents, crackers, &c. As the wheels turn, the pots will successively be fired, and throw into the air a great variety of fires. BALLOON CASES. You must have an oval former, turned of smooth wood; then paste a quantity of brown or cartridge-paper, and let it lie till the paste has soaked all through; this done, rub the former with soap or grease, to prevent the paper from sticking to it; then lay the paper on in small slips, till you have made it one-third of the thickness of the shell intended. Having thus done, set it to dry; and when dry, cut it round the middle, leaving about one inch not cut, which will make the halves join much better than if quite separated. When you have some ready to join, place the halves even together, and let that dry; then lay on paper all over as before, everywhere equal. When the shell is thoroughly dry, burn a vent at top with a square iron. Shells that are designed for stars only, may be made quite round, and the thinner they are at the opening the better; for if they are too strong, the stars are apt to break at the bursting of the shell. Balloons must always be made to go easy into the mortars. MORTARS. These mortars must be made of pasteboard, with a small copper chamber at bottom, in which the powder is to be placed, on which the balloon is to be put. In the centre of the bottom of this chamber make a small hole a little down the foot: the hole must be met by another of the same size as the foot. Then putting a quick-match, or touch-string, of touch-paper, into the hole, your mortar will be ready to be fired. _To load Air Balloons with Stars, Serpents, &c., &c._--When you fill your shells, you must first put in the serpents, rains, &c., or whatever they are composed of, then the blowing powder; but the shells must not be quite filled. All those things must be put in at the fuse-hole, but marrons being too large to go in at the fuse-hole, must be put in before the inside shall be joined. When the shells are loaded, glue and drive in the fuses very tight. The number and quantities of each article for the different shells are as follows: BALLOONS ILLUMINATED. oz. Meal-powder 1 Corn-powder 0-1/2 Powder for the mortar 2 1 oz. driven or rolled stars, or as many as will fill the shell. BALLOONS OR SERPENTS. oz. Meal-powder 1 Corn-powder 1 Powder for the mortar 2-1/2 _Aigrettes._ Mortars to throw aigrettes are generally made of pasteboard, of the same thickness as balloon mortars, and two diameters and a half long in the inside from the top of the foot: the foot must be made of elm without a chamber, but flat at top, and in the same proportions as those for balloon mortars; these mortars must also be bound round with a cord: sometimes eight or nine of these mortars, of about three or four inches diameter, are bound all together, so as to appear but one; but when they are made for this purpose, the bottom of the foot must be of the same diameter as the mortars, and only half a diameter high. The mortars being bound well together, fix them on a heavy solid block of wood. To load these mortars, first put on the inside bottom of each a piece of paper, and on it spread one ounce and a half of meal and corn-powder mixed; then tie the serpents up in parcels with quick-match, and put them in the mortar with their mouths downwards; but take care the parcels do not fit too tight in the mortars, and that all the serpents have been well primed with powder wetted with spirit of wine. On the top of the serpents in each mortar lay some paper or tow; then carry a leader from one mortar to the other all round, and then from all the outside mortars into that in the middle: these leaders must be put between the cases and the sides of the mortar, down to the powder at bottom: in the centre of the middle mortar fix a fire-pump, or brilliant fountain, which must be open at bottom, and long enough to project out of the mouth of the mortar; then paste papers on the tops of all the mortars. Mortars thus prepared are called a _nest of serpents_. When these mortars are to be fired, light the fire-pump, which when consumed will communicate to all the mortars at once by means of the leaders. For mortars of 8, 9, or 10 inches diameter, the serpents should be made in one and two-ounce cases, six or seven inches long, and fired by a leader brought out of the mouth of the mortar, and turned down on the outside, and the end of it covered with paper, to prevent the sparks of the other works from setting it on fire. For a six-inch mortar, let the quantity of powder for firing be two ounces; for an eight-inch, two ounces and three-quarters; and for a ten-inch, three ounces and three-quarters. Care must be taken in these, as well as small mortars, not to put in the serpents too tight, for fear of bursting the mortars. These mortars may be loaded with stars, crackers, &c. If the mortars, when loaded, are sent to any distance, or liable to be much moved, the firing powder should be secured from getting amongst the serpents, which would endanger the mortars, as well as hurt their performance. To prevent this, load the mortars thus: First put in the firing powder, and spread it equally about; then cut a round piece of blue touch-paper, equal to the exterior diameter of the mortar, and draw on it a circle equal to the interior diameter of the mortar, and notch it all round as far as that circle: then paste that part which is notched, and put it down the mortar close to the powder, and stick the pasted edge to the mortar: this will keep the powder always smooth at bottom, so that it may be moved or carried anywhere without receiving damage. The large single mortars are called _pots des aigrettes_. FIRE-PUMPS, OR ROMAN CANDLES. Cases for fire-pumps are made like those for tourbillons; only they are pasted instead of being rolled dry. Having rolled and dried your cases fill them: first put in a little meal-powder and then a star, on which ram, lightly, a ladle or two of composition, then a little meal-powder, and on that a star; then again composition, and so on till you have filled the case. Stars for fire-pumps should not be round, but must be made either square, or flat and circular with a hole through the middle: the quantity of powder for throwing the stars must increase as you come near the top of the case; for, if much powder be put at the bottom, it will burst the case. The stars must differ in size in this manner: let the star which you put in first be a little less than the bore of the case; but let the next star be a little larger, and the third star a little larger than the second, and so on: let them increase in diameter till within two of the top of the case, which two must fit in tight. As the loading of fire-pumps is somewhat difficult, it will be necessary to make two or three trials before you depend on their performance. When you fill a number of pumps, take care not to put in each an equal quantity of charge between the stars, so that when they are fired they may not throw up too many stars together. Cases for fire-pumps should be made very strong, and rolled on 4 or 8-ounce formers, 10 or 12 inches long each. CHARGE. lb. oz. lb. oz. Saltpetre 5 0 Saltpetre 5 0 Brimstone 1 0 Brimstone 2 0 Meal-powder 1-1/2 0 Meal-powder 1 8 Glass-dust 1 0 Glass-dust 1 8 AN ARTIFICIAL EARTHQUAKE. Mix the following ingredients to a paste, with water; bury it in the ground, and in a few hours the earth will break open in several places: lb. oz. Sulphur 4 0 Steel-dust 4 0 _Chinese Fountains._ To make a Chinese fountain, you must have a perpendicular piece of wood, seven feet long, and two inches and a half square. Sixteen inches from the top, fix on the front a cross piece one inch thick, and two and a half broad, with the broad side upwards; below this, fix three more pieces of the same width and thickness, at sixteen inches from each other; let the bottom rail be five feet long, and the others of such a length as to allow the fire-pumps to stand in the middle of the intervals of each other. The pyramid being thus made, fix in the holes made in the bottom rail five fire-pumps, at equal distances; on the second rail, place four pumps; on the third, three; on the fourth, two; and on the top of the post, one; but place them all to incline a little forward, that, when they throw out the stars, they may not strike against the cross-rails. Having fixed your fire-pumps, clothe them with leaders, so that they may all be fired together. _The Dodecahedron,_ So called because it nearly represents a twelve-sided figure, is made thus: First have a ball turned out of some hard wood, 14 inches diameter; divide its surface into 14 equal parts, from which bore holes one inch and a half diameter, perpendicular to the centre, so that they may all meet in the middle: then let there be turned in the inside of each hole a female screw; and to all the holes but one must be made a round spoke five feet long, with four inches of the screw at one end to fit the holes; then in the screw-end of all the spokes bore a hole five inches long, which must be bored slanting, so as to come out at one side, a little above the screw; from which cut a small groove along the spoke within six inches of the other end, where make another hole through to the other side of the spoke. In this end fix a spindle, on which put a small wheel of three or four sides, each side six or seven inches long; these sides must have grooves cut in them large enough to receive a two or four-ounce case. When these wheels are clothed, put them on the spindles, and at the end of each spindle put a nut, to keep the wheel from falling off. The wheels being thus fixed, carry a pipe from the mouth of the first case on each wheel, through the hole in the side of the spoke, and from thence along the groove, and through the other hole, so as to hang out at the screw-end about an inch. The spokes being all prepared in this manner, you must have a post, on which you intend to fire the work, with an iron screw in the top of it, to fit one of the holes in the ball: on the screw fix the ball; then in the top hole of the ball put a little meal-powder and some loose quick-match: then screw in all the spokes; and in one side of the ball bore a hole, in which put a leader, and secure it at the end, and the work will be ready to be fired. By the leader the powder and match in the centre is fired, which will light the match at the ends of the spokes all at once, whereby all the wheels will be lighted at once. There may be an addition to this piece, by fixing a small globe on each wheel, or one on the top wheel only. A grey charge will be proper for the wheel-cases. _Stars with Points._ These stars are made of different sizes, according to the work for which they are intended; they are made with cases from one ounce to one pound, but in general with four-ounce cases, four or five inches long: the case must be rolled with paste, and twice as thick as that of a rocket of the same bore. Having rolled a case, pinch one end of it quite close; then drive in half a diameter of clay; and when the case is dry, fill it with composition two or three inches to the length of the cases with which it is to burn: at top of the charge drive some clay; as the ends of these cases are seldom pinched, they would be liable to take fire. Having filled a case, divide the circumference of it at the pinched end close to the clay, into five equal parts; then bore five holes with a gimblet about the size of the neck of a common four-ounce case, into the composition; from one hole to the other carry a quick-match, and secure it with paper: this paper must be put on in the manner of that on the end of wheel-cases, so that the hollow part, which projects from the end of the case, may serve to receive a leader from any other work, to give fire to the points of the stars. These stars may be made with any number of points. _Fixed Sun with a transparent Face._ To make a sun of the best kind, there should be two rows of cases, which should show a double glory, and make the rays strong and full. The frame or sun-wheel must be made thus: have a circular flat nave made very strong, 12 inches diameter; to this fix six strong flat spokes; on the front of these fix a circular fell, five feet diameter; within which, fix another fell, the length of one of the sun-cases less in diameter; within this fix a third fell, whose diameter must be less than the second by the length of one case and one-third. The wheel being made, divide the fells into so many equal parts as there are to be cases, (which may be done from 24 to 44:) at each division fix a flat iron staple: these staples must be made to fit the cases, to hold them fast on the wheel; let the staples be so placed, that one row of cases may lie in the middle of the intervals of the other. In the centre of the block of the sun drive a spindle, on which put a small hexagonal wheel, whose cases must be filled with the same charge as the cases of the sun; two cases of this wheel must burn at a time, and begin with those on the fells. Having fixed on all the cases, carry pipes of communication from one to the other, and from one side of the sun to the wheel in the middle, and from thence to the other side of the sun. These leaders will hold the wheel steady while the sun is fixing up, and will also be a sure method of lighting both cases of the wheel together. A sun thus made is called a _brilliant sun_, because the wood-work is entirely covered with fire from the wheel in the middle, so that there appears nothing but sparks of brilliant fire; but if you would have a transparent face in the centre, you must have one made of pasteboard of any size. The method of making a face is, by cutting out the eyes, nose, and mouth, for the sparks of the wheel to appear through; but instead of this face, you may have one painted on oil paper, or Persian silk, strained tight on a hoop; which hoop must be supported by three or four pieces of wire at six inches distance from the wheel in the centre, so that the light of it may illuminate the face. By this method may be shown, in the front of the sun, VIVAT REGINA, cut in pasteboard, or Apollo, painted in silk; but, for a small collection, a sun with a single glory and a wheel in front will be most suitable. Half-pound cases, filled ten inches with composition, will be a good size for a sun of five feet diameter; but, if larger, the cases must be greater in proportion. DETONATING WORKS. WATERLOO CRACKERS. Take a slip of cartridge-paper, about three-quarters of an inch in width, paste and double it; let it remain till dry, and cut it into two equal parts in length, (No. 1 and 2,) according to the following pattern: +-----------------+---+-------+--------+ | No. 1. Glass. | S | Glass.| No. 2. | +-----------------+---+-------+--------+ Take some of the glass composition, and lay it across the paper as in the pattern, and put about a quarter of a grain of fulminating silver in the place marked S, and while the glass composition is moist, put the paper marked No. 2, over the farthest row of glass. Over all, paste twice over the part that covers the silver a piece of paper; let it dry, and when you wish to explode it, take hold of the two ends and pull them sharply from each other, and it will produce a loud report. DETONATING GIRDLE. Procure a piece of girth from 12 to 18 inches in length. Double it, and fold it down about 1-1/2 inch, similar to the fold of a letter, and then turn back one end of the girth, and it will form two compartments. Then take some gum and dissolve it in water; boil it till it is quite melted, and very thick; add coarse powdered glass, sufficient to make it into a very thick paste; place two upright rows of the glass composition in the inside of one of the folds, about as wide as the thickness of a lath, and as high as a half-crown laid flat; and when they are dry, sew the first fold together on the edge, and then the second at the opposite end, so that one end may be open. Then, in the centre of the two rows, put about a grain of fulminating silver, and paste a piece of cotton or silk over it. Make a hole at each end of the girdle, and hang it to a hook in the door-post, and the other hook on the door, observing to place the silk part so that it may come against the edge of the door when opened, which will cause a report as loud as a small cannon. The fulminating silver may be purchased at any of the operating chemists. DETONATING BALLS. Procure some glass globes, between the size of a pea and a small marble, in which there must be a small hole; put into it half a grain of fulminating silver. Paste a piece of paper carefully over the ball to prevent the silver from escaping. When you wish to explode one put it on the ground, and tread hard upon it, and it will go off with a loud noise. These balls may be made productive of much amusement in company, by placing a chair lightly on them; for whoever sits down upon them will cause them to explode. These globes may be procured at the barometer-makers. THE DETONATING TAPE. Is made of binding, about three-eighths of an inch in width. Observe the same directions as given for the girdle; you may either explode it yourself, by taking hold of each end, and rolling the ends from each other sharply, or give one end to another, and pull together. DETONATING CARDS. Take a piece of card about three-fourths of an inch in breadth and 12 in length; slit it at one end, and place in the opening a quarter of a grain of fulminating silver; close the edges down with a little paste, and when dry you may use it by lighting the end in a candle. Having given the method by which these loud reports are produced, we shall mention some other effects to be produced by the silver, capable of affording much amusement. For instance, by placing about a quarter of a grain of the silver in the midst of some tobacco in a pipe, or between the leaves of a cigar, and closing the end again, to prevent the powder from falling out; when lighted, it causes a loud explosion; for heat, as well as friction, will equally do. Or, take one-third of the grain of fulminating silver; fold it up in a small piece of paper, and wrap it up in another piece, and paste it round a pin. These pins stuck in the wick of a candle make a very loud noise. Fulminating silver may be also used in the following manner:--Put half a grain in a piece of glass-paper, and enclose it in a piece of foil; put it then at the bottom or side of a drawer, and on opening or shutting it, it will immediately go off. Put a quarter of a grain of fulminating silver into a piece of paper, and place in the snuffers when quite cold; when the candle is snuffed, it will go off. AQUATIC FIRE-WORKS. Works that sport in the water are much esteemed by most admirers of fire-works, particularly water-rockets; and as they seem of a very extraordinary nature to those who are unacquainted with this art, they merit a particular explanation. _Water-Rockets._ They may be made from four ounces to two pounds. If larger, they are too heavy; so that it will be difficult to make them keep above water without a cork float, which must be tied to the neck of the case; but the rockets will not dive so well with as without floats. Cases for these are made in the same manner and proportion as sky-rockets, only a little thicker of paper. When you fill those which are driven solid, put in first one ladleful of slow fire, then two of the proper charge, and on that one or two ladles of sinking charge, then the proper charge, then the sinking charge again, and so on, till you have filled the case within three diameters; then drive on the composition one ladleful of clay; through which make a small hole to the charge; then fill the case, within half a diameter, with corn-powder, on which turn down two or three rounds of the case in the inside; then pinch and tie the end very tight; having filled the rockets, (according to the above directions,) dip their ends in melted resin or sealing-wax, or else secure them well with grease. When you fire those rockets, throw in six or eight at a time; but, if you would have them all sink, or swim, at the same time, you must fill them with an equal quantity of composition, and fire them together. _Pipes of Communication for Water._ They may be used under water, but must be a little thicker in the paper than those for land. Having rolled a sufficient number of pipes, and kept them till dry, wash them over with drying oil, and set them to dry; but when you oil them, leave about an inch and a half at each end dry, for joints; as, if they were oiled all over, when you come to join them, the paste will not stick where the paper is greasy: after the leaders are joined, and the paste dry, oil the joints. These pipes will lie many hours under water, without receiving any damage. _Horizontal Water-Wheels._ To make horizontal wheels for the water, first get a large wooden bowl without a handle; then have an eight-sided wheel, made of a flat board 18 inches diameter, so that the length of each side may nearly be seven inches: in all the sides cut a groove for the cases to lie in. This wheel being made, nail it on the top of the bowl; then take four eight-ounce cases, filled with a proper charge, each about six inches in length. Now, to clothe the wheel with these cases, get some whitish-brown paper, and cut it into slips; being pasted all over on one side, take one of the cases, and roll one of the slips of paper about an inch and a half on its end, so that there will remain about two inches and a half of the paper hollow from the end of the case: tie this case on one of the sides of the wheel, near the corners of which must be holes bored, through which put the packthread to tie the cases: having tied on the first case at the neck and end, put a little meal-powder in the hollow paper; then paste a slip of paper on the end of another case, the head of which put into the hollow paper on the first, allowing a sufficient distance from the tail of one to the head of the other, for the pasted paper to bend without tearing: tie on the second case as you did the first, and so on with the rest, except the last, which must be closed at the end, unless it is to communicate to any thing on the top of the wheel, such as fire-pumps or brilliant fires, fixed in holes cut in the wheel, and fired by the last or second case, as the fancy directs: six, eight, or any number, may be placed on the top of the wheel, provided they are not too heavy for the bowl. Before trying on the cases, cut the upper part of all their ends, except the last, a little shelving, that the fire from one may play over the other, without being obstructed by the case. Wheel-cases have no clay driven in their ends, nor pinched, but are always left open, only the last, or those which are not to lead fire, which must be well secured. _Water-Mines._ For water-mines you must have a bowl with a wheel on it, made in the same manner as the water-wheel; only in its middle there must be a hole, of the same diameter as that of the intended mine. These mines are tin pots, with strong bottoms, and a little more than two diameters in length: the mine must be fixed in the hole in the wheel, with its bottom resting on the bowl; then loaded with serpents, crackers, stars, small water-rockets, &c., in the same manner as pots of aigrettes; but in their centre fix a case of Chinese fire, or a small gerbe, which must be lighted at the beginning of the last case on the wheel. These wheels are to be clothed as usual. _Fire Globes for the Water._ Bowls for water-globes must be very large, and the wheels on them of ten sides: on each side nail a piece of wood four inches long; and on the outside of each piece cut a groove, wide enough to receive about one-fourth of the thickness of a four-ounce case: these pieces of wood must be nailed in the middle of each face of the wheel, and fixed in an oblique direction, so that the fire from the cases may incline upwards: the wheel being thus prepared, tie in each groove a four-ounce case filled with a grey charge; then carry a leader from the tail of one case to the mouth of the other. Globes for these wheels are made of two in hoops, with their edges outwards, fixed one within the other, at right angles. The diameter of these hoops must be rather less than that of the wheel. Having made the globe, drive in the centre of the wheel an iron spindle which must stand perpendicular, and its length be four or six inches more than the diameter of the globe. The spindle serves for an axis, on which is fixed the globe, which must stand four or six inches from the wheel; round one side of each hoop must be soldered little bits of tin, two inches and a half distance from each other; which pieces must be two inches in length each, and only fastened at one end, the other ends being left loose, to turn round the small port-fires, and hold them on: these port-fires must be made of such a length as will last out the cases on the wheel. There need not be any port-fires at the bottom of the globe within four inches of the spindle, as they would have no effect but to burn the wheel: all the port-fires must be placed perpendicularly from the centre of the globe, with their mouths outwards, and must be clothed with leaders, so as all to take fire with the second case of the wheel; and the cases must burn two at a time, one opposite the other. When two cases of a wheel begin together, two will end together; therefore the two opposite end cases must have their ends pinched and secured from fire. The method of firing such wheels is, by carrying a leader from the mouth of one of the first cases to that of the other; and the leader being burnt through the middle, will give fire to both at the same time. _Odoriferous Water-Balloons._ They are made in the same manner as air-balloons, but very thin of paper, and in diameter one inch and three-fourths, with a vent of half an inch diameter. The shells being made, and quite dry, fill them with any of the following compositions, which must be rammed in tight: these balloons must be fired at the vent, and put into a bowl of water. Odoriferous works are generally fired in rooms. _Composition I._ Saltpetre two ounces, flour of sulphur one ounce, camphor half an ounce, yellow amber half an ounce, charcoal-dust three-fourths of an ounce, salt of Benzoin half an ounce, all powdered very fine and well mixed. II. Saltpetre twelve ounces, meal-powder three ounces, frankincense one ounce, myrrh half an ounce, camphor half an ounce, charcoal three ounces, all moistened with the oil of spike. III. Saltpetre two ounces, sulphur half an ounce, antimony half an ounce, amber half an ounce, cedar raspings one-fourth of an ounce, all mixed with the oil of roses and a few drops of bergamot. IV. Saltpetre four ounces, sulphur one ounce, saw-dust of juniper half an ounce, saw-dust of cypress one ounce, camphor one-fourth of an ounce, myrrh two drachms, dried rosemary one-fourth of an ounce, all moistened a little with the oil of roses. N.B. Water-rockets may be made with any of the above compositions, with a little alteration, to make them weaker or stronger, according to the size of the cases. _A Sea-fight with small Ships and a Fire-ship._ Having procured four or five small ships, of two or three feet in length, make a number of small reports, which are to serve for guns. Of these range as many as you please on each side of the upper decks; then at the head and stern of each ship fix a two-ounce case, eight inches long, filled with a slow port-fire composition; but take care to place it in such a manner that the fire may fall in the water, and not burn the rigging; in these cases bore holes at unequal distances from one another, but make as many in each case as half the number of reports, so that one case may fire the guns on one side, and the other those on the opposite. The method of firing the guns is, by carrying a leader from the holes in the cases to the reports on the decks; you must make these leaders very small, and be careful in calculating the burning of the slow fire in the regulating cases, that more than two guns be not fired at a time. When you would have a broadside given, let a leader be carried to a cracker placed on the outside of the ship; which cracker must be tied loose, or the reports will be too slow: in all the ships put artificial guns at the port-holes. Reports for these and similar occasions are made by filling small cartridges with grained powder, pinching them close at each end, and, when used, boring a hole in the side, to which is placed a match or leader for firing them. Having filled and bored holes in two port-fires, for regulating the guns in one ship, make all the rest exactly the same; then, when you begin the engagement, light one ship first, and set it a sailing, and so on with the rest, sending them out singly, which will make them fire regularly, at different times, without confusion; for the time between the firing of each gun will be equal to that of lighting the slow fires. The fire-ship may be of any size, and need not be very good, for it is always lost in the action. To prepare a ship for this purpose, make a port-fire equal in size with those in the other ships, and place it at the stern; in every port place a larger port-fire, filled with a very strong composition, and painted in imitation of a gun, and let them all be fired at once by a leader from the slow fire, within two or three diameters of its bottom; all along both sides, on the top of the upper deck, lay star-composition about half an inch thick and one broad, which must be wetted with thin size, then primed with meal-powder, and secured from fire by pasting paper over it; in the place where you lay this composition, drive some little tacks with flat heads, to hold it fast to the deck; this must be fired just after the sham guns, and when burning will show a flame all round the ship: at the head take up the decks, and put in a tin mortar loaded with crackers, which mortar must be fired by a pipe from the end of the slow fire: the firing of this mortar will sink the ship, and make a pretty conclusion. The regulating port-fire of this ship must be lighted at the same time with the first fighting ship. Having prepared all the ships for fighting, we shall next proceed with the management of them when on the water. At one end of the pond, just under the surface of the water, fit two running blocks, at what distance you choose the ships should fight; and at the other end of the pond, opposite to each of these blocks, under the water, fix a double block; then on the land, by each of the double blocks, place two small windlasses; round one of them turn one end of a small cord, and put the other end through one of the blocks; then carry it through the single one at the opposite end of the pond, and bring it back through the double block again, and round the other windlass: to this cord, near the double block, tie as many small strings as half the number of the ships, at any distance; but these strings must not be more than two feet long each: make fast the loose end of each to a ship, just under her bowsprit; for if tied to the keel, or too near the water, it will overset the ship. Half the ships being thus prepared, near the other double block fix two more windlasses, to which fasten a cord, and to it tie the other half of the ships as before: when you fire the ships, pull in the cord with one of the windlasses, to get all the ships together; and when you have set fire to the first, turn that windlass which draws them out, and so on with the rest, till they are all out in the middle of the pond; then, by turning the other windlass, you will draw them back again; by which method you may make them change sides, and tack about backwards and forwards at pleasure. For the fire-ship fix the blocks and windlasses between the others, so that when she sails out she will be between the other ships: you must not let this ship advance till the guns at her ports take fire. _To fire Sky-Rockets under Water._ You must have stands made as usual, only the rails must be placed flat instead of edgewise, and have holes in them for the rocket-sticks to go through; for if they were hung upon hooks, the motion of the water would throw them off: the stands being made, if the pond be deep enough, sink them at the sides so deep, that, when the rockets are in, their heads may just appear above the surface of the water; to the mouth of each rocket fix a leader, which put through the hole with a stick; then a little above the water must be a board, supported by the stand, and placed along one side of the rockets; then the ends of the leaders are turned up through holes made in this board, exactly opposite the rockets. By this means you may fire them singly or all at once. Rockets may be fired by this method in the middle of a pond, by a Neptune, a swan, a water-wheel, or any thing else you choose. _Neptune in his Chariot._ To represent Neptune in his chariot, you must have a Neptune (made of wood, or basket-work) as big as life, fixed on a float large enough to bear his weight; on which must be two horses' heads and necks, so as to seem swimming. For the wheels of the chariot, there must be two vertical wheels of black fire, and on Neptune's head a horizontal wheel of brilliant fire, with all its cases, to play upwards. When this wheel is made, cover it with paper or pasteboard, cut and painted like Neptune's coronet; then let the trident be made without prongs, but instead of them, fix three cases of a weak grey charge, and on each horse's head put an eight-ounce case of brilliant fire, and on the mouth of each fix a short case, of the same diameter, filled with the white flame composition enough to last out all the cases on the wheels: these short cases must be open at bottom, that they may light the brilliant fires; for the horses' eyes put small port-fires, and in each nostril put a small case half filled with grey charge, and the rest with port-fire composition. If Neptune is to give fire to any building on the water, at his first setting out, the wheels of the chariot, and that on his head, with the white flame on the horses' heads, and the port-fires in their eyes and nostrils, must all be lighted at once; then from the bottom of the white flames carry a leader to the trident. As Neptune is to advance by the help of a block and cord, you must manage it so as not to let him turn about, till the brilliant fires on the horses and the trident begin; for it is by the fire from the horses (which plays almost upright,) that the building, or work, is lighted, which must be thus prepared. From the mouth of the case which is to be first fired, hang some loose quick-match to receive the fire from the horses. When Neptune is only to be shown by himself, without setting fire to any other works, let the white flames on the horses be very short, and not to last longer than one case of each wheel, and let two cases of each wheel burn at a time. _Swans and Ducks in Water._ If you would have swans or ducks discharge rockets into the water, they must be made hollow, and of paper, and filled with small water-rockets, with some blowing powder to throw them out; but if this is not done, they may be made of wood, which will last many times. Having made and painted some swans, fix them on floats; then in the places where their eyes should be, bore holes two inches deep, inclining downwards, and wide enough to receive a small port-fire; the port-fire cases for this purpose must be made of brass, two inches long, and filled with a slow bright charge. In the middle of one of these cases make a little hole; then put the port-fire in the eye-hole of the swan, leaving about half an inch to project out; and in the other eye put another port-fire, with a hole made in it: then in the neck of the swan, within two inches of one of the eyes, bore a hole slantwise, to meet that in the port-fire; in this hole put a leader, and carry it to a water-rocket, that must be fixed under the tail with its mouth upwards. On the top of the head place two one-ounce cases, four inches long each, driven with brilliant fire; one of these cases must incline forwards, and the other backwards: these must be lighted at the same time as the water-rocket; to do which, bore a hole between them in the top of the swan's head, down to the hole in the port-fire, to which carry a leader: if the swan is filled with rockets, they must be fired by a pipe from the end of the water-rocket under the tail. When you set the swan a swimming, light the two eyes. _Water Fire-Fountains._ To make a fire-fountain for the water, first have a float made of wood, three feet diameter; then in the middle fix a round perpendicular post, four feet high, and two inches diameter; round this post fix three circular wheels made of thin wood, without any spokes. The largest of these wheels must be placed within two or three inches of the float, and must be nearly of the same diameter. The second wheel must be two feet two inches diameter, and fixed at two feet distance from the first. The third wheel must be one foot four inches diameter, and fixed within six inches of the top of the post: the wheels being fixed, take 18 four or eight-ounce cases of brilliant fire, and place them round the first wheel with their mouths outwards, and inclining downwards; on the second wheel place 13 cases of the same, and in the same manner as those on the first; on the third, place eight more of these cases, in the same manner as before, and on the top of the post fix a gerbe; then clothe all the cases with leaders, so that both they and the gerbe may take fire at the same time. Before firing this work, try it in the water, to see whether the float is properly made, so as to keep the fountain upright. THE END. MISCELLANEOUS WORKS IN VARIOUS DEPARTMENTS OF LITERATURE, PUBLISHED BY LEA AND BLANCHARD. ACTON'S MODERN COOKERY, with cuts, 12mo, cloth. 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Together with numerous works in all departments of Medical Science, Catalogues of which can be had on application. * * * * * THE AMERICAN ENCYCLOPÆDIA. BROUGHT UP TO 1847. THE ENCYCLOPÆDIA AMERICANA: A POPULAR DICTIONARY OF ARTS, SCIENCES, LITERATURE, HISTORY, POLITICS, AND BIOGRAPHY, IN FOURTEEN LARGE OCTAVO VOLUMES OF OVER SIX HUNDRED DOUBLE COLUMNED PAGES EACH. For sale very low, in various styles of binding. Some years having elapsed since the original thirteen volumes of the ENCYCLOPÆDIA AMERICANA were published, to bring it up to the present day, with the history of that period, at the request of numerous subscribers, the publishers have just issued a SUPPLEMENTARY VOLUME (THE FOURTEENTH), BRINGING THE WORK UP TO THE YEAR 1847. EDITED BY HENRY VETHAKE, LL.D. Vice-Provost and Professor of Mathematics in the University of Pennsylvania, Author of "A Treatise on Political Economy." In one large octavo volume of over 650 double columned pages. The numerous subscribers who have been waiting the completion of this volume can now perfect their sets, and all who want A REGISTER OF THE EVENTS OF THE LAST FIFTEEN YEARS, FOR THE WHOLE WORLD, can obtain this volume separately: price Two Dollars uncut in cloth, or Two Dollars and Fifty cents in leather, to match the styles in which the publishers have been selling sets. Subscribers in the large cities can be supplied on application at any of the principal bookstores; and persons residing in the country can have their sets matched by sending a volume in charge of friends visiting the city. "This volume is worth owning by itself, as a most convenient and reliable compend of recent History, Biography, Statistics, &c., &c. The entire work forms the cheapest and probably now the most desirable Encyclopædia published for popular use."--_New York Tribune._ "The Conversations Lexicon (Encyclopædia Americana) has become a household book in all the intelligent families in America, and is undoubtedly the best depository of biographical, historical, geographical, and political information of that kind which discriminating readers require."--_Silliman's Journal._ "This volume of the Encyclopædia is a Westminster Abbey of American reputation. What names are on the roll since 1833!"--_N. Y. Literary World._ "The work to which this volume forms a supplement, is one of the most important contributions that has ever been made to the literature of our country. Besides condensing into a comparatively narrow compass, the substance of larger works of the same kind which had preceded it, it contains a vast amount of information that is not elsewhere to be found, and is distinguished, not less for its admirable arrangement, than for the variety of subjects of which it treats. The present volume, which is edited by one of the most distinguished scholars of our country, is worthy to follow in the train of those which have preceded it. It is a remarkably felicitous condensation of the more recent improvements in science and the arts, besides forming a very important addition to the department of Biography, the general progress of society, &c., &c."--_Albany Argus._ * * * * * CAMPBELL'S LORD CHANCELLORS. NOW COMPLETE. LIVES OF THE LORD CHANCELLORS AND KEEPERS OF THE GREAT SEAL OF ENGLAND. FROM THE EARLIEST TIMES TO THE REIGN OF KING GEORGE IV., BY JOHN LORD CAMPBELL, A.M., F.R.S.E. Now complete in seven handsome crown octavo volumes. _Bringing the work to the death of Lord Eldon, 1838._ "The volumes teem with exciting incidents, abound in portraits, sketches, and anecdotes, and are at once interesting and instructive. The work is not only historical and biographical, but it is anecdotical and philosophical. Many of the chapters embody thrilling incidents, while as a whole, the publication may be regarded as of a high intellectual order."--_Inquirer._ * * * * * MURRAY'S ENCYCLOPÆDIA OF GEOGRAPHY. THE ENCYCLOPÆDIA OF GEOGRAPHY, COMPRISING A COMPLETE DESCRIPTION OF THE EARTH, PHYSICAL, STATISTICAL, CIVIL, AND POLITICAL. EXHIBITING ITS RELATION TO THE HEAVENLY BODIES, ITS PHYSICAL STRUCTURE, THE NATURAL HISTORY OF EACH COUNTRY, AND THE INDUSTRY, COMMERCE, POLITICAL INSTITUTIONS, AND CIVIL AND SOCIAL STATE OF ALL NATIONS. BY HUGH MURRAY, F.R.S.E., &c. Assisted in Botany by Professor HOOKER--Zoology, &c., by W. W. SWAINSON--Astronomy &c., by Professor WALLACE--Geology, &c., by Professor JAMESON. REVISED, WITH ADDITIONS, BY THOMAS G. BRADFORD. THE WHOLE BROUGHT UP, BY A SUPPLEMENT, TO 1843. _In three large octavo volumes,_ VARIOUS STYLES OF BINDING. This great work, furnished at a remarkably cheap rate, contains about NINETEEN HUNDRED LARGE IMPERIAL PAGES, and is illustrated by EIGHTY-TWO SMALL MAPS, and a colored MAP OF THE UNITED STATES, after Tanner's, together with about ELEVEN HUNDRED WOOD-CUTS, executed in the best style. * * * * * SCHOOL BOOKS. BIRD'S NATURAL PHILOSOPHY. NOW READY. ELEMENTS OF NATURAL PHILOSOPHY, BEING AN EXPERIMENTAL INTRODUCTION TO THE PHYSICAL SCIENCES. ILLUSTRATED WITH OVER THREE HUNDRED WOOD-CUTS. BY GOLDING BIRD, M.D., Assistant Physician to Guy's Hospital. FROM THE THIRD LONDON EDITION. In one neat volume. "By the appearance of Dr. Bird's work, the student has now all that he can desire in one neat, concise, and well-digested volume. The elements of natural philosophy are explained in very simple language, and illustrated by numerous wood-cuts."--_Medical Gazette._ "A volume of useful and beautiful instruction for the young."--_Literary Gazette._ "We should like to know that Dr. Bird's book was associated with every boys' and girls' school throughout the kingdom."--_Medical Gazette._ "This work marks an advance which has long been wanting in our system of instruction. Mr. Bird has succeeded in producing an elementary work of great merit."--_Athenæum._ * * * * * HERSCHELL'S ASTRONOMY. A TREATISE ON ASTRONOMY, BY SIR JOHN F. W. HERSCHELL, F. R. S., &c. WITH NUMEROUS PLATES AND WOOD-CUTS. A NEW EDITION, WITH A PREFACE AND A SERIES OF QUESTIONS, BY S. C. WALKER. In one volume, 12mo. * * * * * BREWSTER'S OPTICS. ELEMENTS OF OPTICS, BY SIR DAVID BREWSTER. WITH NOTES AND ADDITIONS, BY A. D. BACHE, LL.D. Superintendent of the Coast Survey, &c. In one volume, 12mo., with numerous wood-cuts. * * * * * MULLER'S PHYSICS AND METEOROLOGY. NOW READY. PRINCIPLES OF PHYSICS AND METEOROLOGY, BY J. MULLER, Professor of Physics at the University of Freiburg. ILLUSTRATED WITH NEARLY FIVE HUNDRED AND FIFTY ENGRAVINGS ON WOOD, AND TWO COLORED PLATES. In one octavo volume. TRANSLATOR'S PREFACE. In laying the following pages before the public, it seems necessary to state that the design of them is to render more easily accessible a greater portion of the general principles of Physics and Meteorology than is usually to be obtained, without the sacrifice of a greater amount of time and labour than most persons can afford, or are willing to make. The subjects of which this volume treats are very numerous--more numerous, in fact, than at first sight it would seem possible to embrace in so small a compass. The Author has, however, by a system of the most judicious selection and condensation, been enabled to introduce all the most important facts and theories relating to Statics, Hydrostatics, Dynamics, Hydrodynamics, Pneumatics, the Laws of the Motions of Waves in general, Sound, the Theory of Musical Notes, the Voice and Hearing, Geometrical and Physical Optics, Magnetism, Electricity and Galvanism, in all their subdivisions, Heat and Meteorology, within the space of an ordinary middle-sized volume. Of the manner in which the translator has executed his task, it behoves him to say nothing; he has attempted nothing more than a plain, and nearly literal version of the original. He cannot, however, conclude this brief introductory note without directing the attention of his Readers to the splendid manner in which the Publishers have illustrated this volume. _August, 1847._ "The Physics of Muller is a work, superb, complete, unique: the greatest want known to English Science could not have been better supplied. The work is of surpassing interest. The value of this contribution to the scientific records of this country may be duly estimated by the fact, that the cost of the original drawings and engravings alone has exceeded the sum of 2000£."--_Lancet_, March, 1847. "The plan adopted by Muller is simple; it reminds us of the excellent and popular treatise published many years since by Dr. Arnott, but it takes a much wider range of subjects. Like it, all the necessary explanations are given in clear and concise language, without more than an occasional reference to mathematics; and the treatise is most abundantly illustrated with well-executed wood engravings. "The author has actually contrived to comprise in about five hundred pages, including the space occupied by illustrations, Mechanics, the Laws of Motion, Acoustics, Light, Magnetism, Electricity, Galvanism, Electro-Magnetism, Heat, and Meteorology. "Medical practitioners and students, even if they have the means to procure, have certainly not the time to study an elaborate treatise in every branch of science: and the question therefore is, simply, whether they are to remain wholly ignorant of such subjects, or to make a profitable use of the labours of those who have the happy art of saying or suggesting much in a small space. "From our examination of this volume, we do not hesitate to recommend it to our readers as a useful book on a most interesting branch of science. We may remark, that the translation is so well executed, that we think the translator is doing himself injustice by concealing his name."--_London Medical Gazette_, August, 1847. * * * * * GRAHAM'S CHEMISTRY. NEARLY READY. ELEMENTS OF CHEMISTRY, INCLUDING THE APPLICATIONS OF THE SCIENCE IN THE ARTS. BY T. GRAHAM, F. R. S., &c. SECOND AMERICAN, FROM THE SECOND LONDON EDITION. EDITED AND REVISED BY ROBERT BRIDGES, M.D., Professor of Chemistry in the Franklin Medical College, Philadelphia. In one large octavo volume, with numerous wood-engravings. This edition will be found enlarged and improved, so as to be fully brought up to a level with the science of the day. * * * * * ARNOTT'S PHYSICS. ELEMENTS OF PHYSICS; OR, NATURAL PHILOSOPHY, GENERAL AND MEDICAL. WRITTEN FOR UNIVERSAL USE, IN PLAIN, OR NON-TECHNICAL LANGUAGE. BY NIELL ARNOTT, M.D. A NEW EDITION, BY ISAAC HAYS, M.D. Complete in one octavo volume, with nearly two hundred wood-cuts. This standard work has been long and favourably known as one of the best popular expositions of the interesting science it treats of. It is extensively used in many of the first seminaries. * * * * * ELEMENTARY CHEMISTRY, THEORETICAL AND PRACTICAL, BY GEORGE FOWNES, Ph.D., Chemical Lecturer in the Middlesex Hospital Medical School, &c., &c. WITH NUMEROUS ILLUSTRATIONS. EDITED, WITH ADDITIONS, BY ROBERT BRIDGES, M.D., Professor of General and Pharmaceutical Chemistry in the Philadelphia College of Pharmacy, &c., &c. SECOND AMERICAN EDITION. In one large duodecimo volume, sheep, or extra cloth, with nearly two hundred wood-cuts. The character of this work is such as to recommend it to all colleges and academies in want of a text-book. It is fully brought up to the day, containing all the late views and discoveries that have so entirely changed the face of the science, and it is completely illustrated with very numerous wood engravings, explanatory of all the different processes and forms of apparatus. Though strictly scientific, it is written with great clearness and simplicity of style, rendering it easy to be comprehended by those who are commencing the study. It may be had well bound in leather, or neatly done up in strong cloth. Its low price places it within the reach of all. _Extract of a letter from Professor Millington, of William and Mary College, Va._ "I have perused the book with much pleasure, and find it a most admirable work; and, to my mind, such a one as is just now much needed in schools and colleges. * * * All the books I have met with on chemistry are either too puerile or too erudite, and I confess Dr. Fownes' book seems to be the happiest medium I have seen, and admirably suited to fill up the hiatus." Though this work has been so recently published, it has already been adopted as a text-book by a large number of the higher schools and colleges throughout the country, and many of the Medical Institutions. As a work for the upper classes in academies and the junior students of colleges, there has been but one opinion expressed concerning it, and it may now be considered as THE TEXT-BOOK for the Chemical Student. * * * * * POPULAR SCIENCE. KIRBY AND SPENCE'S ENTOMOLOGY, FOR POPULAR USE. AN INTRODUCTION TO ENTOMOLOGY, OR, ELEMENTS OF THE NATURAL HISTORY OF INSECTS; COMPRISING AN ACCOUNT OF NOXIOUS AND USEFUL INSECTS, OF THEIR METAMORPHOSES, FOOD, STRATAGEMS, HABITATIONS, SOCIETIES, MOTIONS, NOISES, HYBERNATION, INSTINCT, &c., &c. With Plates, Plain or Colored. BY W. KIRBY, M.A., F.R.S., AND W. SPENCE, ESQ., F.R.S. FROM THE SIXTH LONDON EDITION, WHICH WAS CORRECTED AND MUCH ENLARGED. In one large octavo volume, extra cloth. "We have been greatly interested in running over the pages of this treatise. There is scarcely, in the wide range of natural science, a more interesting or instructive study than that of insects, or one that is calculated to excite more curiosity or wonder. "The popular form of letters is adopted by the authors in imparting a knowledge of the subject, which renders the work peculiarly fitted for our district school libraries, which are open to all ages and classes."--_Hunt's Merchants' Magazine._ * * * * * JOHNSON AND LANDRETH ON FRUIT, KITCHEN, AND FLOWER GARDENING. A DICTIONARY OF MODERN GARDENING, BY GEORGE WILLIAM JOHNSON, ESQ. Author of the "Principles of Practical Gardening," "The Gardener's Almanac," &c. WITH ONE HUNDRED AND EIGHTY WOOD-CUTS. EDITED, WITH NUMEROUS ADDITIONS, BY DAVID LANDRETH, OF PHILADELPHIA. In one large royal duodecimo volume, extra cloth, of nearly Six Hundred and Fifty double columned Pages. This edition has been greatly altered from the original. Many articles of little interest to Americans have been curtailed or wholly omitted, and much new matter, with numerous illustrations, added, especially with respect to the varieties of fruit which experience has shown to be peculiarly adapted to our climate. Still, the editor admits that he has only followed in the path so admirably marked out by Mr. Johnson, to whom the chief merit of the work belongs. It has been an object with the editor and publishers to increase its popular character, thereby adapting it to the larger class of horticultural readers in this country, and they trust it will prove what they have desired it to be, an Encyclopædia of Gardening, if not of Rural Affairs, so condensed and at such a price as to be within reach of nearly all whom those subjects interest. * * * * * GRAHAME'S COLONIAL HISTORY. HISTORY OF THE UNITED STATES. FROM THE PLANTATION OF THE BRITISH COLONIES TILL THEIR ASSUMPTION OF INDEPENDENCE. SECOND AMERICAN EDITION, ENLARGED AND AMENDED, WITH A MEMOIR BY PRESIDENT QUINCY. IN TWO LARGE OCTAVO VOLUMES, EXTRA CLOTH, WITH A PORTRAIT. This work having assumed the position of a standard history of this country, the publishers have been induced to issue an edition in smaller size and at a less cost, that its circulation may be commensurate with its merits. It is now considered as the most impartial and trustworthy history that has yet appeared. A few copies of the edition in four volumes, on extra fine thick paper, price eight dollars, may still be had by gentlemen desirous of procuring a beautiful work for their libraries. * * * * * ANSTED'S ANCIENT WORLD. JUST ISSUED. THE ANCIENT WORLD, OR, PICTURESQUE SKETCHES OF CREATION, BY D. T. ANSTED, M. A., F.R.S, F.G.S., &c. PROFESSOR OF GEOLOGY, IN KING'S COLLEGE, LONDON. In one very neat volume, fine extra cloth, with about One Hundred and Fifty Illustrations. The object of this work is to present to the general reader the chief results of Geological investigation in a simple and comprehensive manner. The author has avoided all minute details of geological formations and particular observations, and has endeavoured as far as possible to present striking views of the wonderful results of the science, divested of its mere technicalities. The work is printed in a handsome manner, with numerous illustrations, and forms a neat volume for the centre table. "As a resume of what is at present known on the subject of fossil remains, it is worthy to be a companion to the author's 'Descriptive Geology,' a work of which we have spoken in the highest terms. This volume is illustrated in the style of all Van Voorst's Natural History works, and that is sufficient recommendation. Our extracts will convey a notion of the style of the work, which is, like all that Professor Ansted has written, clear and pointed.--_Athenæum._ * * * * * CHEMISTRY OF THE FOUR SEASONS, SPRING, SUMMER, AUTUMN, AND WINTER. AN ESSAY, PRINCIPALLY CONCERNING NATURAL PHENOMENA, ADMITTING OF INTERPRETATION BY CHEMICAL SCIENCE, AND ILLUSTRATING PASSAGES OF SCRIPTURE. BY THOMAS GRIFFITHS, Professor of Chemistry in the Medical College of St. Bartholomew's Hospital, &c. In one large royal 12mo. volume, with many Wood-Cuts, extra cloth. "Chemistry is assuredly one of the most useful and interesting of the natural sciences. Chemical changes meet us at every step, and during every season, the winds and the rain, the heat and the frosts, each have their peculiar and appropriate phenomena. And those who have hitherto remained insensible to these changes and unmoved amid such remarkable, and often startling results, will lose their apathy upon reading the Chemistry of the 'Four Seasons,' and be prepared to enjoy the highest intellectual pleasures. Conceived in a happy spirit, and written with taste and elegance, the essay of Mr. Griffiths cannot fail to receive the admiration of cultivated minds; and those who have looked less carefully into nature's beauties, will find themselves led on step by step, until they realize a new intellectual being. Such works, we believe, exert a happy influence over society, and hence we hope that the present one may be extensively read."--_The Western Lancet._ * * * * * PHILOSOPHY IN SPORT, MADE SCIENCE IN EARNEST; BEING AN ATTEMPT TO ILLUSTRATE THE FIRST PRINCIPLES OF NATURAL PHILOSOPHY, BY THE AID OF THE POPULAR TOYS AND SPORTS OF YOUTH. FROM THE SIXTH AND GREATLY IMPROVED LONDON EDITION. In one very neat royal 18mo. volume, with nearly one hundred illustrations on wood. Fine extra crimson cloth. "Messrs. Lea & Blanchard have issued, in a beautiful manner, a handsome book, called 'Philosophy in Sport, made Science in Earnest.' This is an admirable attempt to illustrate the first principles of Natural Philosophy, by the aid of the popular toys and sports of youth. Useful information is conveyed in an easy, graceful, yet dignified manner, and rendered easy to the simplest understanding. The book is an admirable one, and must meet with universal favour."--_N. Y. Evening Mirror._ * * * * * ENDLESS AMUSEMENT. JUST ISSUED. ENDLESS AMUSEMENT, A COLLECTION OF NEARLY FOUR HUNDRED ENTERTAINING EXPERIMENTS IN VARIOUS BRANCHES OF SCIENCE, INCLUDING ACOUSTICS, ARITHMETIC, CHEMISTRY, ELECTRICITY, HYDRAULICS, HYDROSTATICS, MAGNETISM, MECHANICS, OPTICS, WONDERS OF THE AIR PUMP, ALL THE POPULAR TRICKS AND CHANGES OF THE CARDS, &c., &c. TO WHICH IS ADDED, A COMPLETE SYSTEM OF PYROTECHNY, OR THE ART OF MAKING FIRE-WORKS: THE WHOLE SO CLEARLY EXPLAINED AS TO BE WITHIN REACH OF THE MOST LIMITED CAPACITY. WITH ILLUSTRATIONS. FROM THE SEVENTH LONDON EDITION. In one neat royal 18mo. volume, fine extra crimson cloth. "It contains everything that can please the grave or the gay. It is 'endless amusement,' and the publishers might have added, instruction. What a help to a dull gathering, or what an able adjunct to a children's party! It may be introduced to the scientific or to the family circle, and to each it will give instruction and pleasure. It is filled with illustrations. We shall give extracts from it occasionally."--_Lady's Book._ * * * * * SOMERVILLE'S PHYSICAL GEOGRAPHY. PHYSICAL GEOGRAPHY. BY MARY SOMERVILLE. AUTHOR OF "CONNECTION OF THE PHYSICAL SCIENCES," ETC. _In one neat royal 12mo. volume, extra cloth._ CONTENTS.--Geology--Form of the Great Continent--Highlands of the Great Continent--Mountain Systems of the Great Continent--Africa--American Continent--Low Lands of South America--Central America--North America--Greenland--Australia--The Ocean--Springs--European Rivers--African Rivers--Asiatic Rivers--River Systems of North America--Rivers of South America--Lakes--The Atmosphere--Vegetation--Vegetation of the Great Continent--Flora of Tropical Asia--African Flora--Australian Flora--American Vegetation--Distribution of Insects--Distribution of Fishes--Distribution of Reptiles--Distribution of Birds--Distribution of Mammalia--Distribution, Conditions and Future Prospects of the Human Race. While reading this work we could not help thinking how interesting, as well as useful, geography as a branch of education might be made in our schools. In many of them, however, this is not accomplished. It is to be hoped that this defect will be remedied; and that in all our educational institutions Geography will soon be taught in the proper way. Mrs. Somerville's work may, in this respect, be pointed to as a model.--_Tait's Edinburgh Magazine_, September, 1848. * * * * * READINGS FOR THE YOUNG. FROM THE WORKS OF SIR WALTER SCOTT. _In two very handsome 18mo. volumes, with beautiful plates, done up in crimson extra cloth._ Messrs. Lea & Blanchard deserve the thanks of all the little people in the land for these delightful volumes, which are as agreeable to read as they are attractive in appearance.--_N. Y. Literary World._ * * * * * TALES AND STORIES FROM HISTORY. BY AGNES STRICKLAND, AUTHOR OF "LIVES OF THE QUEENS OF ENGLAND," ETC. _In one handsome royal 18mo. volume, crimson extra cloth, with illustrations._ In these pretty tales from the legendary and authentic history of England and Continental Europe, Miss Strickland has hit a happy mean in presenting to the mind of youth, fact in its most fascinating, and fiction in its least objectionable garb. It is a little work which will be dog's eared, and pored over with absorbing interest by the school-boy.--_Balt. Patriot._ * * * * * The above works will be found admirable reading books for schools.--Lea & Blanchard also publish the following, which are suitable to advanced classes. A POPULAR TREATISE ON VEGETABLE PHYSIOLOGY. By W. B. Carpenter, M. D. In one royal 12mo. volume, with wood-cuts. THE ANCIENT WORLD; OR, PICTURESQUE SKETCHES OF CREATION. By D. T. Ansted, M. A., F. R. S., F. G. S. In one royal 12mo. volume, with 150 wood-cuts. THE CHEMISTRY OF THE FOUR SEASONS, SPRING, SUMMER, AUTUMN AND WINTER; an Essay principally concerning Natural Phenomena admitting of interpretation by Chemical Science, and illustrating passages of Scripture. By Thomas Griffiths. In one large royal 12mo. volume, with 60 wood-cuts. * * * * * BOY'S TREASURY OF SPORTS. THE BOY'S TREASURY OF SPORTS, PASTIMES AND RECREATIONS. WITH FOUR HUNDRED ILLUSTRATIONS. BY SAMUEL WILLIAMS. IS NOW READY. In one very neat volume, bound in extra crimson cloth; handsomely printed and illustrated with engravings in the first style of art, and containing about six hundred and fifty articles. A present for all seasons. PREFACE. This Illustrated Manual of "Sports, Pastimes, and Recreations," has been prepared with especial regard to the Health, Exercise, and Rational Enjoyment of the young readers to whom it is addressed. Every variety of commendable Recreation will be found in the following pages. First, you have the little Toys of the Nursery; the Tops and Marbles of the Play-ground; and the Balls of the Play-room, or the smooth Lawn. Then, you have a number of Pastimes that serve to gladden the fireside; to light up many faces right joyfully, and make the parlour re-echo with mirth. Next, come the Exercising Sports of the Field, the Green, and the Play-ground; followed by the noble and truly English game of Cricket. Gymnastics are next admitted; then, the delightful recreation of Swimming; and the healthful sport of Skating. Archery, once the pride of England, is then detailed; and very properly followed by Instructions in the graceful accomplishment of Fencing, and the manly and enlivening exercise of Riding. Angling, the pastime of childhood, boyhood, manhood, and old age, is next described; and by attention to the instructions here laid down, the lad with a stick and a string may soon become an expert Angler. Keeping Animals is a favourite pursuit of boyhood. Accordingly, we have described how to rear the Rabbit, the Squirrel, the Dormouse, the Guinea Pig, the Pigeon, and the Silkworm. A long chapter is adapted to the rearing of Song Birds; the several varieties of which, and their respective cages, are next described. And here we may hint, that kindness to Animals invariably denotes an excellent disposition: for, to pet a little creature one hour, and to treat it harshly the next, marks a capricious if not a cruel temper. Humanity is a jewel, which every boy should be proud to wear in his breast. We now approach the more sedate amusements--as Draughts and Chess: two of the noblest exercises of the ingenuity of the human mind. Dominoes and Bagatelle follow. With a knowledge of these four games, who would pass a dull hour in the dreariest day of winter; or who would sit idly by the fire? Amusements in Arithmetic, harmless Legerdemain, or sleight-of-hand, and Tricks with Cards, will delight many a family circle, when the business of the day is over, and the book is laid aside. Although the present volume is a book of amusements, Science has not been excluded from its pages. And why should it be? when Science is as entertaining as a fairy tale. The changes we read of in little nursery-books are not more amusing than the changes in Chemistry, Optics, Electricity, Magnetism, &c. By understanding these, you may almost become a little Magician. Toy Balloons and Paper Fireworks, (or Fireworks _without_ Fire,) come next. Then follow Instructions for Modelling in Card-Board; so that you may build for yourself a palace or a carriage, and, in short, make for yourself a little paper world. Puzzles and Paradoxes, Enigmas and Riddles, and Talking with the Fingers, next make up plenty of exercise for "Guess," and "Guess again." And as you have the "Keys" in your own hand, you may keep your friends in suspense, and make yourself as mysterious as the Sphynx. A chapter of Miscellanies--useful and amusing secrets--winds up the volume. The "Treasury" contains upwards of four hundred Engravings; so that it is not only a collection of "secrets worth knowing," but it is a book of pictures, as full of prints as a Christmas pudding is of plums. It may be as well to mention that the "Treasury" holds many new games that have never before been printed in a book of this kind. The old games have been described afresh. Thus it is, altogether, a new book. And now we take leave, wishing you many hours, and days, and weeks of enjoyment over these pages; and we hope that you may be as happy as this book is brimful of amusement. TRANSCRIBER'S NOTES 1. Passages in italics are surrounded by _underscores_. 2. Images have been moved from the middle of a paragraph to the closest paragraph break. 3. The words coeli, manoeuvre and manoeuvres uses an "oe" ligature in the original. 4. The fractional numbers are represented by a hyphen and a forward slash. For example, 3-1/2 represents three and a half. 5. The following misprints have been corrected: "umlimited" corrected to "unlimited" (page 67) "immerged" corrected to "immersed" (page 124) "shil ing" corrected to "shilling" (page 133) "where-ever" corrected to "wherever" (page 148) "sttll" corrected to "still" (page 149) "mattrasses" corrected to "mattresses" (page 156) 6. Other than the corrections listed above, printer's inconsistencies in spelling, punctuation, and hyphenation, have been retained. 
60862	----	Thirty Degrees Cattywonkus By JAMES BELL _It doesn't take a heap of leaving to make any house a nightmare. One vanishing door will do nastily._ [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, May 1960. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] It was a tremendous house. And they were newlyweds. And were still a mite flighty. And for a while that accounted for the whole thing. At the moment, it seemed to Ernie Lane that in a house which even the real estate agent said had "either" eleven or twelve rooms, it was quite conceivable that he and Melinee had overlooked that extra room. After all, they had only been living at 1312 Cedar Lane for four days and had hardly had time to make a complete survey of the place. Now it was quite different. For Ernie Lane had stopped walking hurriedly past that extra door, had stopped giving it only casual curiosity, had even stopped wondering afterward. This night he had come home a bit tired, gone directly to greet his loving wife, and then decided to put a stop to the gnawing question. While Melinee fried the chicken, Ernie walked carefully and wordlessly to the dim hallway. He went past the staircase, past the telephone, to the darkest spot between the living room and the study. He stood for a strange moment--there was no extra door. He felt the refinished wall, his fingertips searching for hidden panels. There was none. "Supper's ready," Melinee called. "Ernie?" But it had been there last night, the night before, the night before that, and the very first night the real estate agent brought them over. In fact, he recalled, that was the reason the agent had been uncertain about the number of rooms. And why had he passed it off as a joke, simply turning from the extra door without opening it? Ernie felt again. It was ceasing to be a joke. He was not a man of hallucinations. He was not a victim of superstition, fear or near-sightedness. He only wanted to know why he saw a door one day and didn't see it the next. He called a comforting word to his wife, then reached for the telephone book. He found the name of Hartley and Hartley, Real Estate. PLaza 0-6633. Without any undue commotion, he dialed. In a moment, a woman's voice at the other end seemed to barge into his life. "Special operator. Number, please?" "PLaza 0-6633." "Sorry, sir, we have no such number--" Ernie let a disgruntled voice thunder into the phone: "Then what the heck is Hartley and Hartley Realty doing with it?" A pause. Then she replied, "Sir, we have no Hartley and Hartley--" "Don't be silly," he said. "I just found it in the phone book." She answered, "We have a Hartfield and Hatley, Realtors, Inc., sir, but no Hartley and Hartley. Their number is in the directory." Melinee was standing behind him. "Who are you calling?" He was shaken, but he managed to appear calm as he hung up. He even relaxed against the wall. "I was trying to get the real estate agent on the phone--these lights ought to be brighter--and I thought he could refer us to his electrician." "His what?" Melinee asked. "Elec--" He halted. "Never mind, honey. I'm beat--rough day. I need fried chicken." He hugged his trim, prim wife and they walked toward the kitchen arm in arm. But it was not until they settled at the table that he saw, under the bright electric light, that her hair was red, not blonde, and he immediately felt he'd been gypped. Her smirky little voice added to the shock. "Darling, don't call me Melinee when my name is Marsha. It just isn't done." * * * * * On purpose, Ernie spent an uneventful evening, arose the next morning, ignored his wife's red hair, conveniently forgot her name, avoided even checking to see if the door was there, and saved up a sneer for the telephone. During the day, his business life was perfect. He got the Jenkins account, lunched with the boss, and was asked to serve on the membership committee in the Chamber of Commerce drive. However, during the afternoon he developed a terrific headache and excused himself from the office long enough to see the company physician. The thin, foxy doctor handed him a pill and a glass of water. After Ernie had swallowed the pill politely, the physician leaned forward and gazed at his eyes and forehead. "Tell me, Lane--you're a newlywed, aren't you?" Ernie nodded. "Then why the worried frown? You seem to be carrying the Rock of Gibraltar on your shoulders. Is your job too much for you?" "Of course not," Ernie said, smiling. "I told you I had a headache." "Perhaps," the doctor said, smiling back. "You seemed to have been in something of a prepossessed state when you came in. I was just curious." Ernie laughed it off and at the doctor's request lay on a cot for a period of ten minutes. When he returned to the office, there was a request that he call a "Marsha." The sudden venomous thoughts of the evening before spun before his eyes. What the devil was going on with the woman? The new name, the new hair-do, the new smirk in her voice--that wasn't the woman he married. He grabbed the phone and called home. Twenty rings. No answer. It was a quarter of four when the switchboard notified him that his wife was on the line. "Hello, Ernie? This is Melinee. I'm at the Lee Hat Shop. Can you meet me in half an hour? I want to do some shopping and I thought we'd have supper and maybe see a movie." Melinee? It was all like a breath of spring. Away from that house, she was a different person. Happily, he agreed to buying her a new hat, supper and a ticket to Loew's State. For Melinee, anything. For Marsha, nothing. And when they met, surely enough her hair was blonde again and the smirk in her voice was gone. She was his bride, and he forgot whatever the past, present or future might hold. The future, however, was not long coming. After the movie, they returned home and were about to settle down when, passing along the hallway, Ernie looked over his shoulder and saw the extra door. Quickly, he reached past Melinee and grasped the knob with his hand. "Ernie, what on _Earth_!" She startled him. He laughed, and they went in to bed. It was around one A.M. when Ernie decided he would not be able to put off any longer the chore of exploring that hall door. It plainly had not been there the night before; it plainly was there tonight. He tiptoed softly from bed and left the room. Melinee did not even stir. He closed the door lightly and cat-footed his way through the darkness to the wall switch at the foot of the stairs. Stealthily looking all about him, as if someone or something might suddenly try to stop him, Ernie sneaked up on the door. He grabbed the knob with both hands, turned it briskly and the door swung open. The pale green wall of the hallway confronted him. It was as if the door were merely hinged onto the wall. No opening whatever. * * * * * He tapped it with his knuckles. Then he examined the door. It was a French style thing extending from floor to ceiling with contrasting green slats. Identical with those appearing all along the hallways, most of them closet doors. Just for the heck of it, he thought he would drag out a hammer and uncork the screws holding the false door--carry it to some conspicuous place and observe as it went through its next disappearing act. But as he turned to head for the tool cabinet, Ernie heard the din of distant shouting--as if a room-full of men were playing cards. And yet not so distant. For a moment the world became silent. Ernie pressed an ear against the wall behind the false doorway. It seemed to be coming from inside, and there were only a few words of any audible clarity. "Maximum--not much longer--and logarithms--" Ernie tried the adjacent door. It opened into a small storage room, unlighted. He felt around the wall paneling, but no switch. Gauging the dimensions, it seemed to him that the storage room practically accounted for all the space behind the hall. If the fake door opened onto a room, it could only be this room, and there was nothing here. He listened. No sound inside the confines of the room. But the moment he returned, pressed his ear against the outer wall, Ernie heard them shouting again. It was as if the wall were twelve inches thick--as if he were not hearing anything at all--and yet hearing. The thought struck him--there was a laundry chute opening from the second floor to the storage room. Provided they wanted to install a chute. Meanwhile, the agent had told him, it would remain just a hole in the floor. He and Melinee had not made any plans for developing the second floor. It was evident that his mother would one day have to live with them, and her own invalid sister, in time. And then whatever children there might be. But so far he and Melinee had actually made only one trip up there with the agent. In fact, there was no electrical connection to the upstairs whatever. Ernie remembered the layout, however, and made his way up the stairs that creaked in defiance of the agent's compliments. When he reached the top in the pitch blackness, he felt for the wall. A strange coldness not at all common to the summer season moved out along the hallway. It seemed to hover around him, curious of the intruder. Imagination. He walked on, an inch at a time, for he remembered a small table about half way along. But he never felt the table. Ernie reached the end of the hall before he was sure--and where had the table gone? He returned along the opposite wall until he felt the small square paneling. Then a brass knob. He pulled it open, half expecting the end of the world. And at that point, a bluish haze filled with gaseous, luminous smoke rose out and blinded him. When the obnoxious odor of the smoke was gone, he took a deep breath and stuck his head in again. Directly below him sat three men, fat and jovial, shaking their pipes at one another. There was a row of red and white lighted tubes, not unlike fluorescents, a mahoganylike counter that might pass for a bar, and a row of bottles against a mirror. * * * * * The dimensions immediately struck Ernie as all wrong. It was far bigger than the hall closet where it was supposed to be. In fact, the portion he saw seemed to be the focal point of a large dance hall or bar room. But the most obvious quality of the scene was the tilted floor. The whole thing seemed to be about thirty degrees lopsided. Ernie could go immediately back to bed and tell of his dream tomorrow, or he could make things worse by yelling at the men below. * * * * * It wasn't necessary to yell. As if they had seen him through the tops of their balding heads, they motioned to the bartender, then pointed squarely at his vantage point. Ernie felt the quavering impulse to run, and yet even in a nightmare you try desperately to learn the ending. The man in the white coat set the ladder firmly against the floor so that the top ended in the slightest kind of tilt near the chute door. It was not Ernie's intention to crawl through the door, but the way the man motioned, and the way the men turned briefly and waved, simply as if they might be old acquaintances waiting for him in a hotel lobby--it was, to say the very least, overwhelming. There was a fragrance, an allure about the room. It smelled of apples and tobacco and brought nostalgic thoughts of college days and--and faint wisps of the past that were not nostalgic. He thought of Melinee. He really ought to tell her about this. The chalky finger motioning at him, the unconcerned old men on the sofa--and the table. It was the antique table, missing from the upstairs hall, that lured him in. There it sat against the far wall. He grabbed a jutting two-by-four and twisted his body through the opening. The ladder must have been shoved to one side, or perhaps it was the claustrophobic effect of going through the small opening--anyway, something. It turned his mind, his body, wrong-side out. Like the squeezing out of a wet mop by a steamroller. At the foot of the ladder, the man in the bartender's jacket led him to the three men. One of them, exceptionally fat, jovial, excused himself politely and took Ernie aside. "You look pale, Ernie," he said. "Having trouble?" Groggily, Ernie looked about him. "It's this room. It's lopsided. I think a good thirty degrees cattywonkus." The man doused a cigar and a quick frown crossed his brow. "Good point. Very good point. Come with me, Ernie." Ernie looked; the other men paid him no mind. The little man waddled through a maze of foundation columns, as if the whole world were suspended above them. He walked behind the bar to a small glass-encased desk, U-shaped and covered with dials all reading A-B-C-D. "Kronkite!" the man called. A whirring inside the room shut off. A man with goggles and a metal halo stuck his head out the door. "Kronkite, Ernie here says we are thirty degrees off. Can you shift the equilibrium? Frankly, I hadn't noticed it." * * * * * With a silent nod, the man named Kronkite shut the transparent door, turned three knobs, a bell clanged and the floor of the whole affair sank some thirty degrees on one side, rose thirty on the other. Then the whirring in the chamber resumed and Ernie was led back to the bar. "Have yourself a drink, man," his host coaxed. "I don't need one," Ernie said. "Listen, before we go on, just one question--" The man smiled pleasantly. "Where the heck am I? And what is this going on in my basement?" The smile continued. It was maddening. "Well?" said Ernie. "You are here," the man finally said. "And don't be silly, Ernie. Your house has no basement." Ernie turned to the bartender. "I think I _will_ have a drink." "Make it a triple," the little man called, and the bartender smiled as if his face hurt. There was a pained expression on Ernie. He sank his head into his arms. "Cheer up," the man said. "It isn't worth all that." "What isn't?" "Be happy, man." "I'll be happy when I get out of here, but I'll be hilarious when I find out the score--and I plan to be hilarious before I get happy. Is that clear?" "You talk as if you had been drinking already, man. Snap out of it. I like men with clear heads." It was not only a delaying tactic, Ernie thought; it was plainly a case of nerve-busting. They were going to force it out of him. He had already conceded they were not a gang of thieves using his basement for a hideaway; they were not digging a secret tunnel for the Defense Department. "You like men with clear heads? What am I, some sort of recruit?" "Now!" the man exclaimed, suddenly thrust into a new frame of mind. "We are now on the same plane. You _are_ a recruit and we can understand each other now." "So where is this?" "This is your house, of course, but we're not quite there yet. We're in what you would call--oh, another dimension." Ernie reached for the drink and sniffed it. Its smell fitted the situation. "And what does that mean?" "Oh, you and I have lived in the same vicinity all our lives, even crossed each other's paths, but we are in different dimensions--different worlds in the same place." "You mean like Mars and Earth?" "I mean like Mars _in_ Earth, or vice versa," the man answered. Ernie jumped up and started for the ladder. "I'm getting out of here--" "Don't be a fool! Climb that ladder and you'll butt your skull in!" "I came through the hatch. I'll leave through the hatch." "But we've shifted thirty degrees. You told us to. Now the top of the ladder is thirty degrees away from the door of the laundry chute, which is quite impossible to reach, my friend, because there is perhaps dirt and a foundation and everything else in the way. We'd have to tear out our own structure and gouge into yours. This we cannot do. Too expensive." * * * * * Ernie had heard enough. He climbed the ladder to the top, butted his head and climbed down. "Okay. You win. What's the score?" "You and Marsha," the man said. "Melinee," Ernie corrected. "Melinee in your dimension, Marsha in ours. You and she exist in our dimension as well. Same types, same characteristics inwardly. But not the same outwardly. Different hair, different name--your own features were to be slightly different here." Ernie sat down on the sofa beside the two old men. He buried his head. "This is the other dimension? Then where is the other me?" "Oh, no," his host said. "This is not 'the other' dimension. This is the _experimental_ dimension. _You_ are from the second. What we are both in is a third realm sponsored by the government--the federal government of The Unison States. Congrice sponsored this scientific investigation, provided we could accomplish it before the session ends." The first desire to laugh at the stupidity of the nightmare grappled with Ernie. But when he looked at that ladder and remembered the bump on his head, he knew this was not the time or place for a nightmare. The man went on, "So we talked Senatore Jumphries into wielding his might in committee, the committee on extra-dimensional perception talked to the President Eisenhoovelt, he addressed the Congrice, and by the single vote of Demorep Martini, this thing was financed for short duration." Ernie opened his eyes and looked beyond the bar and the experimental lab. It was like the inside of a giant ship in space or a vessel plowing the Pacific. It spread into distant chasms of darkness. "Our object, of course, is to start out the new dimension with an Adam and Eve," the host said. Ernie sneered. "You think you can start a new world!" "Oh, we've begun it. And we chose your home because here you are two young newlyweds just starting out in life, not too concerned that the future holds nothing more for you than junior assistant to the vice president--ever! Here you have more chance for development, advancement and enjoyment. We have effected changes--your Melinee, for example. You and Marsha will run this dimension. You and she will--" "We will not, and I'm going to Melinee now. Let me out of here." The man politely hid a laugh. "Dear sir, I assure you there is no way out of the dimension. You are trapped. You must remain now, regardless, and conduct our experiment for us." "You got through to our world to find out about us," Ernie said. "How can you keep me here?" "But we entered your world from our own dimension. Our people pass back and forth all the time, unknown to your people. But from this special contraption which Congrice has rigged up for us, there is no immediate escape." Ernie got mad. "Then what the devil are these people doing here?" "Sh," the man said, "those are our Congrice observers." He seemed extremely disturbed. "Don't let them know how you feel. They get angry at people who take them on wild-goose chases." * * * * * There was a sudden feeling of hope that Ernie held a monkey wrench in his hand. First, he would find out all about the thing, then he would raise hail Columbia to the two Congrice observers and get them to thumbs-down the experiment. Then, if there was an ounce of humaneness in them, they would free him. "Okay, I'll calm down. But let me know the rest. When will I see Melinee?" "Marsha," the man said firmly, "will be along shortly. We must first lift the initial dimension prototype to the exact level of your house. Every coordinate must match each stick of furniture in your own dimension. Then we can begin working outward--" "Working outward?" "From your house. It is to be the beginning of this--er--civilization you and Marsha are to create. You will observe in each direction there is still darkness? When we have manipulated the realm into the exact position of the ground floor of your house, we will install a series of transitional burnouts. These will break down molecular resistance which our more powerful equipment creates on solid portions of your house. Everything will fit into place, and you and Marsha will report to us regularly." Ernie was fuming. "Then we are your prisoners?" "Oh, but you'll enjoy every minute of it! We created the origin, the nucleus, in the home of some newlywed in your dimension for the mere purpose of convenience of adaptability. We will bring in teams who will plant ersatz crops, trees, cut streams, create weather--put life into the whole place. With your dimension's home and our dimension's scientific advantages, you can have full reign of populating a wonderful new world." Ernie was madder than he had ever remembered. "And if I refuse?" "You can't refuse. Marsha will be here momentarily; we have been experimenting with her changes in hair, mood, expression--we hypnotized her on occasions. The extra door in the hallways? Sooner or later she will see it, wonder as you did and open it. This time we will have the magnetic field force turned on. You see, Ernie, you came in the wrong way and--" and here he paused abruptly--"quite a problem has been posed." "I'll say it has!" "Yes. You see, you were supposed to come through the door, and you still will, for there was a technical miscalculation in our instruments which, while allowing you to enter this new dimension, also did not allow you to enter. You yourself suggested we correct by thirty whole degrees. Well, we are not set up for more than one field force entrance per person. The Congrice didn't allot us that much money." Ernie's eyes grew wild and bright. "So, technically, I'm not even here?" "Technically, your other self is still up by the laundry chute looking in or going back to bed, or whatever." He scratched his balding head. "Really an unfortunate event. For when the other you enters our hallway door, we shall have to do away with one of you. It would not only frighten Marsha, but the federal government would accuse us of waste, corruption and heaven knows what else." The wildness in Ernie's eyes turned into a gleam. "You mean your government just wouldn't understand?" "Right," the man said unhappily. "There's more politics in science than you'd ever believe possible." "Mister, I think I have a solution." "You _have_?" * * * * * Ernie walked to the bar, grabbed an armful of magnums, then walked to the plastic experimental table, flung open the door, slung bottle after bottle at the instruments, caused three small explosions, a sputtering red fire, a terrible burst of black smoke and a sudden explosion that turned the whole new dimension--such as it was--into a white blinding sun. When the nausea left, he saw the bodies lying on a green grassy area in what seemed to be Washington, D. C. He made his way in torn pajamas to Unison Station, paid a man to go out and buy him a second-hand suit by giving up his gold wedding band, then found the Senatoreale Office Building, located the office of the Senatore of Iowaki, as he had planned to do, and asked for permission to enter the "other" dimension to take home movies. The senatore asked him the name of his home town, accused him of lisping it, handed him a year's free pass to Other World and a two-year pass to the Senatoreale in session. Ernie, following instructions on the card, walked to a little white building near the Washingable Monument, stepped inside, handed a man his Other World card, then walked through a door, felt sick at his stomach, came out to the streetcar line to Melinee and home. When he got there, it was almost daylight, and the front door was locked. He climbed through an upstairs window, looked through the laundry chute, saw nothing and returned to his bed. Melinee was still sleeping soundly. He wrestled with his pillow a while. Then the alarm went off. The rest was simple. At breakfast he told her he was taking the day off. "Darling, why on Earth?" "We're moving," he said. "But _why_?" "There was an explosion in the night. I think it was gas escaping." "We might have died!" she cried. Ernie closed his eyes. "Go look in the hall, dear, and tell me what you see." When she returned, she was in a quandary. "Well?" he asked. "Did you see that crazy extra door blown off the wall?" "No, Ernie, but there's a man at the door in pajamas like yours who claims he's been following you." Ernie squinted. "Who is he?" "He says his name is Irvin--" "Irvin?" Ernie barked. "--and, dear, he's the spitting image of you." 
61228	----	THE BIG HEADACHE BY JIM HARMON What's the principal cause of headaches? Why, having a head, of course! [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, September 1962. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] I "Do you think we'll have to use force on Macklin to get him to cooperate in the experiment?" Ferris asked eagerly. "How are you going to go about forcing him, Doctor?" Mitchell inquired. "He outweighs you by fifty pounds and you needn't look to _me_ for help against that repatriated fullback." Ferris fingered the collar of his starched lab smock. "Guess I got carried away for a moment. But Macklin is exactly what we need for a quick, dramatic test. We've had it if he turns us down." "I know," Mitchell said, exhaling deeply. "Somehow the men with the money just can't seem to understand basic research. Who would have financed a study of cyclic periods of the hedgehog? Yet the information gained from that study is vital in cancer research." "When we prove our results that should be of enough practical value for anyone. But those crummy trustees didn't even leave us enough for a field test." Ferris scrubbed his thin hand over the bony ridge of his forehead. "I've been worrying so much about this I've got the ancestor of all headaches." Mitchell's blue eyes narrowed and his boyish face took on an expression of demonic intensity. "Ferris, would you consider--?" "No!" the smaller man yelled. "You can't expect me to violate professional ethics and test my own discovery on myself." "_Our_ discovery," Mitchell said politely. "That's what I meant to say. But I'm not sure it would be completely ethical with even a discovery partly mine." "You're right. Besides who cares if you or I are cured of headaches? Our reputations don't go outside our own fields," Mitchell said. "But now Macklin--" Elliot Macklin had inherited the reputation of the late Albert Einstein in the popular mind. He was the man people thought of when the word "mathematician" or even "scientist" was mentioned. No one knew whether his Theory of Spatium was correct or not because no one had yet been able to frame an argument with it. Macklin was in his early fifties but looked in his late thirties, with the build of a football player. The government took up a lot of his time using him as the symbol of the Ideal Scientist to help recruit Science and Engineering Cadets. For the past seven years Macklin--who _was_ the Advanced Studies Department of Firestone University--had been involved in devising a faster-than-light drive to help the Army reach Pluto and eventually the nearer stars. Mitchell had overheard two coeds talking and so knew that the project was nearing completion. If so, it was a case of _Ad astra per aspirin_. The only thing that could delay the project was Macklin's health. Despite his impressive body, some years before he had suffered a mild stroke ... or at least a vascular spasm of a cerebral artery. It was known that he suffered from the vilest variety of migraine. A cycle of the headaches had caused him to be absent from his classes for several weeks, and there were an unusual number of military uniforms seen around the campus. * * * * * Ferris paced off the tidy measurements of the office outside the laboratory in the biology building. Mitchell sat slumped in the chair behind the blond imitation wood desk, watching him disinterestedly. "Do you suppose the Great Man will actually show up?" Ferris demanded, pausing in mid-stride. "I imagine he will," Mitchell said. "Macklin's always seemed a decent enough fellow when I've had lunch with him or seen him at the trustees meetings." "He's always treated me like dirt," Ferris said heatedly. "Everyone on this campus treats biologists like dirt. Sometimes I want to bash in their smug faces." Sometimes, Mitchell reflected, Ferris displayed a certain lack of scientific detachment. There came a discreet knock on the door. "Please come in," Mitchell said. Elliot Macklin entered in a cloud of pipe smoke and a tweed jacket. He looked more than a little like a postgraduate student, and Mitchell suspected that that was his intention. He shook hands warmly with Mitchell. "Good of you to ask me over, Steven." Macklin threw a big arm across Ferris' shoulders. "How have you been, Harold?" Ferris' face flickered between pink and white. "Fine, thank you, doctor." Macklin dropped on the edge of the desk and adjusted his pipe. "Now what's this about you wanting my help on something? And please keep the explanation simple. Biology isn't my field, you know." Mitchell moved around the desk casually. "Actually, Doctor, we haven't the right to ask this of a man of your importance. There may be an element of risk." The mathematician clamped onto his pipe and showed his teeth. "Now you have me intrigued. What is it all about?" "Doctor, we understand you have severe headaches," Mitchell said. Macklin nodded. "That's right, Steven. Migraine." "That must be terrible," Ferris said. "All your fine reputation and lavish salary can't be much consolation when that ripping, tearing agony begins, can it?" "No, Harold, it isn't," Macklin admitted. "What does your project have to do with my headaches?" "Doctor," Mitchell said, "what would you say the most common complaint of man is?" "I would have said the common cold," Macklin replied, "but I suppose from what you have said you mean headaches." * * * * * "Headaches," Mitchell agreed. "Everybody has them at some time in his life. Some people have them every day. Some are driven to suicide by their headaches." "Yes," Macklin said. "But think," Ferris interjected, "what a boon it would be if everyone could be cured of headaches _forever_ by one simple injection." "I don't suppose the manufacturers of aspirin would like you. But it would please about everybody else." "Aspirins would still be used to reduce fever and relieve muscular pains," Mitchell said. "I see. Are you two saying you _have_ such a shot? Can you cure headaches?" "We think we can," Ferris said. "How can you have a specific for a number of different causes?" Macklin asked. "I know that much about the subject." "There _are_ a number of different causes for headaches--nervous strain, fatigue, physical diseases from kidney complaints to tumors, over-indulgence--but there is one _effect_ of all of this, the one real cause of headaches," Mitchell announced. "We have definitely established this for this first time," Ferris added. "That's fine," Macklin said, sucking on his pipe. "And this effect that produces headaches is?" "The pressure effect caused by pituitrin in the brain," Mitchell said eagerly. "That is, the constriction of blood vessels in the telencephalon section of the frontal lobes. It's caused by an over-production of the pituitary gland. We have artificially bred a virus that feeds on pituitrin." "That may mean the end of headaches, but I would think it would mean the end of the race as well," Macklin said. "In certain areas it is valuable to have a constriction of blood vessels." "The virus," Ferris explained, "can easily be localized and stabilized. A colony of virus in the brain cells will relax the cerebral vessels--and only the cerebral vessels--so that the cerebrospinal fluid doesn't create pressure in the cavities of the brain." The mathematician took the pipe out of his mouth. "If this really works, I could stop using that damned gynergen, couldn't I? The stuff makes me violently sick to my stomach. But it's better than the migraine. How should I go about removing my curse?" He reinserted the pipe. "I assure you, you can forget ergotamine tartrate," Ferris said. "Our discovery will work." * * * * * "Will work," Macklin said thoughtfully. "The operative word. It _hasn't_ worked then?" "Certainly it has," Ferris said. "On rats, on chimps...." "But not on humans?" Macklin asked. "Not yet," Mitchell admitted. "Well," Macklin said. "Well." He thumped pipe ashes out into his palm. "Certainly you can get volunteers. Convicts. Conscientious objectors from the Army." "We want you," Ferris told him. Macklin coughed. "I don't want to overestimate my value but the government wouldn't like it very well if I died in the middle of this project. My wife would like it even less." Ferris turned his back on the mathematician. Mitchell could see him mouthing the word _yellow_. "Doctor," Mitchell said quickly, "I know it's a tremendous favor to ask of a man of your position. But you can understand our problem. Unless we can produce quick, conclusive and dramatic proof of our studies we can get no more financial backing. We _should_ run a large-scale field test. But we haven't the time or money for that. We can cure the headaches of one person and that's the limit of our resources." "I'm tempted," Macklin said hesitantly, "but the answer is go. I mean '_no_'. I'd like to help you out, but I'm afraid I owe too much to others to take the rest--the risk, I mean." Macklin ran the back of his knuckles across his forehead. "I really would like to take you up on it. When I start making slips like that it means another attack of migraine. The drilling, grinding pain through my temples and around my eyeballs. The flashes of light, the rioting pools of color playing on the back of my lids. Ugh." Ferris smiled. "Gynergen makes you sick, does it, doctor? Produces nausea, eh? The pain of that turns you almost wrong side out, doesn't it? You aren't much better off with it than without, are you? I've heard some say they preferred the migraine." Macklin carefully arranged his pipe along with the tools he used to tend it in a worn leather case. "Tell me," he said, "what is the worst that could happen to me?" "Low blood pressure," Ferris said. "That's not so bad," Macklin said. "How low can it get?" "When your heart stops, your blood pressure goes to its lowest point," Mitchell said. A dew of perspiration had bloomed on Macklin's forehead. "Is there much risk of that?" "Practically none," Mitchell said. "We have to give you the worst possibilities. _All_ our test animals survived and seem perfectly happy and contented. As I said, the virus is self-stabilizing. Ferris and I are confident that there is no danger.... But we may be wrong." Macklin held his head in both hands. "Why did you two select _me_?" "You're an important man, doctor," Ferris said. "Nobody would care if Mitchell or I cured ourselves of headaches--they might not even believe us if we said we did. But the proper authorities will believe a man of your reputation. Besides, neither of us has a record of chronic migraine. You do." "Yes, I do," Macklin said. "Very well. Go ahead. Give me your injection." Mitchell cleared his throat. "Are you positive, doctor?" he asked uncertainly. "Perhaps you would like a few days to think it over." "No! I'm ready. Go ahead, right now." "There's a simple release," Ferris said smoothly. Macklin groped in his pocket for a pen. II "Ferris!" Mitchell yelled, slamming the laboratory door behind him. "Right here," the small man said briskly. He was sitting at a work table, penciling notes. "I've been expecting you." "Doctor--Harold--you shouldn't have given this story to the newspapers," Mitchell said. He tapped the back of his hand against the folded paper. "On the contrary, I should and I did," Ferris answered. "We wanted something dramatic to show to the trustees and here it is." "Yes, we wanted to show our proof to the trustees--but not broadcast unverified results to the press. It's too early for that!" "Don't be so stuffy and conservative, Mitchell! Macklin's cured, isn't he? By established periodic cycle he should be suffering hell right now, shouldn't he? But thanks to our treatment he is perfectly happy, with no unfortunate side effects such as gynergen produces." "It's a significant test case, yes. But not enough to go to the newspapers with. If it wasn't enough to go to the press with, it wasn't enough to try and breach the trustees with. Don't you see? The public will hand down a ukase demanding our virus, just as they demanded the Salk vaccine and the Grennell serum." "But--" The shrill call of the telephone interrupted Mitchell's objections. Ferris excused himself and crossed to the instrument. He answered it and listened for a moment, his face growing impatient. "It's Macklin's wife," Ferris said. "Do you want to talk to her? I'm no good with hysterical women." "Hysterical?" Mitchell muttered in alarm and went to the phone. "Hello?" Mitchell said reluctantly. "Mrs. Macklin?" "You are the other one," the clear feminine voice said. "Your name is Mitchell." She couldn't have sounded calmer or more self-possessed, Mitchell thought. "That's right, Mrs. Macklin. I'm Dr. Steven Mitchell, Dr. Ferris's associate." "Do you have a license to dispense narcotics?" "What do you mean by that, Mrs. Macklin," Mitchell said sharply. "I used to be a nurse, Dr. Mitchell. I know you've given my husband heroin." "That's absurd. What makes you think a thing like that?" "The--trance he's in now." "Now, Mrs. Macklin. Neither Dr. Ferris or myself have been near your husband for a full day. The effects of a narcotic would have worn off by this time." "Most known narcotics," she admitted, "but evidently you have discovered something new. Is it so expensive to refine you and Ferris have to recruit new customers to keep yourselves supplied?" "Mrs. Macklin! I think I had better talk to you later when you are calmer." Mitchell dropped the receiver heavily. "What could be wrong with Macklin?" he asked without removing his hand from the telephone. Ferris frowned, making quotation marks above his nose. "Let's have a look at the test animals." Together they marched over to the cages and peered through the honeycomb pattern of the wire. The test chimp, Dean, was sitting peacefully in a corner scratching under his arms with the back of his knuckles. Jerry, their control in the experiment, who was practically Dean's twin except that he had received no injection of the E-M Virus, was stomping up and down punching his fingers through the wire, worrying the lock on the cage. "Jerry _is_ a great deal more active than Dean," Mitchell said. "Yes, but Dean isn't sick. He just doesn't seem to have as much nervous energy to burn up. Nothing wrong with his thyroid either." They went to the smaller cages. They found the situation with the rats, Bud and Lou, much the same. "I don't know. Maybe they just have tired blood," Mitchell ventured. "Iron deficiency anemia?" "Never mind, doctor. It was a form of humor. I think we had better see exactly what is wrong with Elliot Macklin." "There's nothing wrong with him," Ferris snapped. "He's probably just trying to get us in trouble, the ingrate!" * * * * * Macklin's traditional ranch house was small but attractive in aqua-tinted aluminum. Under Mitchell's thumb the bell chimbed _dum-de-de-dum-dum-dum_. As they waited Mitchell glanced at Ferris. He seemed completely undisturbed, perhaps slightly curious. The door unlatched and swung back. "Mrs. Macklin," Mitchell said quickly, "I'm sure we can help if there is anything wrong with your husband. This is Dr. Ferris. I am Dr. Mitchell." "You had certainly _better_ help him, gentlemen." She stood out of the doorway for them to pass. Mrs. Macklin was an attractive brunette in her late thirties. She wore an expensive yellow dress. And she had a sharp-cornered jawline. The Army officer came out into the hall to meet them. "You are the gentlemen who gave Dr. Macklin the unauthorized injection," he said. It wasn't a question. "I don't like that 'unauthorized'," Ferris snapped. The colonel--Mitchell spotted the eagles on his green tunic--lifted a heavy eyebrow. "No? Are you medical doctors? Are you authorized to treat illnesses?" "We weren't treating an illness," Mitchell said. "We were discovering a method of treatment. What concern is it of yours?" The colonel smiled thinly. "Dr. Macklin is my concern. And everything that happens to him. The Army doesn't like what you have done to him." Mitchell wondered desperately just what they had done to the man. "Can we see him?" Mitchell asked. "Why not? You can't do much worse than murder him now. That might be just as well. We have laws to cover that." The colonel led them into the comfortable, over-feminine living room. Macklin sat in an easy chair draped in embroidery, smoking. Mitchell suddenly realized Macklin used a pipe as a form of masculine protest to his home surroundings. On the coffee table in front of Macklin were some odd-shaped building blocks such as were used in nursery schools. A second uniformed man--another colonel but with the snake-entwined staff of the medical corps in his insignia--was kneeling at the table on the marble-effect carpet. The Army physician stood up and brushed his knees, undusted from the scrupulously clean rug. "What's wrong with him, Sidney?" the other officer asked the doctor. "Not a thing," Sidney said. "He's the healthiest, happiest, most well-adjusted man I've ever examined, Carson." "But--" Colonel Carson protested. "Oh, he's changed all right," the Army doctor answered. "He's not the same man as he used to be." "How is he different?" Mitchell demanded. The medic examined Mitchell and Ferris critically before answering. "He used to be a mathematical genius." "And now?" Mitchell said impatiently. "Now he is a moron," the medic said. III Mitchell tried to stop Colonel Sidney as he went past, but the doctor mumbled he had a report to make. Mitchell and Ferris stared at Colonel Carson and Macklin and at each other. "What did he mean, Macklin is an idiot?" Mitchell asked. "Not an idiot," Colonel Carson corrected primly. "Dr. Macklin is a moron. He's legally responsible, but he's extremely stupid." "I'm not so dumb," Macklin said defensively. "I beg your pardon, sir," Carson said. "I didn't intend any offense. But according to all the standard intelligence tests we have given you, your clinical intelligence quotient is that of a moron." "That's just on book learning," Macklin said. "There's a lot you learn in life that you don't get out of books, son." "I'm confident that's true, sir," Colonel Carson said. He turned to the two biologists. "Perhaps we had better speak outside." "But--" Mitchell said, impatient to examine Macklin for himself. "Very well. Let's step into the hall." Ferris followed them docilely. "What have you done to him?" the colonel asked straightforwardly. "We merely cured him of his headaches," Mitchell said. "How?" Mitchell did his best to explain the F-M Virus. "You mean," the Army officer said levelly "you have infected him with some kind of a disease to rot his brain?" "No, no! Could I talk to the other man, the doctor? Maybe I can make him understand." "All I want to know is why Elliot Macklin has been made as simple as if he had been kicked in the head by a mule," Colonel Carson said. "I think I can explain," Ferris interrupted. "You can?" Mitchell said. Ferris nodded. "We made a slight miscalculation. It appears as if the virus colony overcontrols the supply of posterior pituitary extract in the cerebrum. It isn't more than necessary to stop headaches. But that necessary amount of control to stop pain is too much to allow the brain cells to function properly." "Why won't they function?" Carson roared. "They don't get enough food--blood, oxygen, hemoglobin," Ferris explained. "The cerebral vessels don't contract enough to pump the blood through the brain as fast and as hard as is needed. The brain cells remain sluggish, dormant. Perhaps decaying." The colonel yelled. Mitchell groaned. He was abruptly sure Ferris was correct. * * * * * The colonel drew himself to attention, fists trembling at his sides. "I'll see you hung for treason! Don't you know what Elliot Macklin means to us? Do you want those filthy Luxemburgians to reach Pluto before we do? Macklin's formula is essential to the FTL engine. You might just as well have blown up Washington, D.C. Better! The capital is replaceable. But the chances of an Elliot Macklin are very nearly once in a human race." "Just a moment," Mitchell interrupted, "we can cure Macklin." "You _can_?" Carson said. For a moment Mitchell thought the man was going to clasp his hands and sink to his knees. "Certainly. We have learned to stabilize the virus colonies. We have antitoxin to combat the virus. We had always thought of it as a beneficial parasite, but we can wipe it out if necessary." "Good!" Carson clasped his hands and gave at least slightly at the knees. "Just you wait a second now, boys," Elliot Macklin said. He was leaning in the doorway, holding his pipe. "I've been listening to what you've been saying and I don't like it." "What do you mean you don't like it?" Carson demanded. He added, "Sir?" "I figure you mean to put me back like I used to be." "Yes, doctor," Mitchell said eagerly, "just as you used to be." "_With_ my headaches, like before?" Mitchell coughed into his fist for an instant, to give him time to frame an answer. "Unfortunately, yes. Apparently if your mind functions properly once again you will have the headaches again. Our research is a dismal failure." "I wouldn't go that far," Ferris remarked cheerfully. Mitchell was about to ask his associate what he meant when he saw Macklin slowly shaking his head. "No, sir!" the mathematician said. "I shall not go back to my original state. I can remember what it was like. Always worrying, worrying, worrying." "You mean wondering," Mitchell said. Macklin nodded. "Troubled, anyway. Disturbed by every little thing. How high was up, which infinity was bigger than what infinity--say, what was an infinity anyway? All that sort of schoolboy things. It's peaceful this way. My head doesn't hurt. I've got a good-looking wife and all the money I need. I've got it made. Why worry?" Colonel Carson opened his mouth, then closed it. "That's right, Colonel. There's no use in arguing with him," Mitchell said. "It's not his decision to make," the colonel said. "He's an idiot now." "No, Colonel. As you said, he's a moron. He seems an idiot compared to his former level of intelligence but he's legally responsible. There are millions of morons running around loose in the United States. They can get married, own property, vote, even hold office. Many of them do. You can't force him into being cured.... At least, I don't _think_ you can." "No, I can't. This is hardly a totalitarian state." The colonel looked momentarily glum that it wasn't. Mitchell looked back at Macklin. "Where did his wife get to, Colonel? I don't think that even previously he made too many personal decisions for himself. Perhaps she could influence him." "Maybe," the colonel said. "Let's find her." * * * * * They found Mrs. Macklin in the dining room, her face at the picture window an attractive silhouette. She turned as the men approached. "Mrs. Macklin," the colonel began, "these gentlemen believe they can cure your husband of his present condition." "Really?" she said. "Did you speak to Elliot about that?" "Y-yes," Colonel Carson said, "but he's not himself. He refused the treatment. He wants to remain in his state of lower intelligence." She nodded. "If those are his wishes, I can't go against them." "But Mrs. Macklin!" Mitchell protested. "You will have to get a court order overruling your husband's wishes." She smoothed an eyebrow with the third finger of her right hand. "That was my original thought. But I've redecided." "Redecided!" Carson burst out almost hysterically. "Yes. I can't go against Elliot's wishes. It would be monstrous to put him back where he would suffer the hell of those headaches once again, where he never had a moment's peace from worry and pressure. He's happy now. Like a child, but happy." "Mrs. Macklin," the Army man said levelly, "if you don't help us restore your husband's mind we will be forced to get a court order declaring him incompetent." "But he is not! Legally, I mean," the woman stormed. "Maybe not. It's a borderline case. But I think any court would give us the edge where restoring the mind of Elliot Macklin was concerned. Once he's certified incompetent, authorities can rule whether Mitchell and Ferris' antitoxin treatment is the best method of restoring Dr. Macklin to sanity." "I doubt very much if the court would rule in that manner," she said. The colonel looked smug. "Why not?" "Because, Colonel, the matter of my husband's health, his very life, is involved." "There is some degree of risk in shock treatments, too. But--" "It isn't quite the same, Colonel. Elliot Macklin has a history of vascular spasm, a mild pseudostroke some years ago. Now you want to give those cerebral arteries back the ability to constrict. To paralyze. To kill. No court would give you that authority." "I suppose there's some chance of that. But without the treatment there is _no_ chance of your husband regaining his right senses, Mrs. Macklin," Mitchell interjected. Her mouth grew petulant. "I don't care. I would rather have a live husband than a dead genius. I can take care of him this way, make him comfortable...." Carson opened his mouth and closed his fist, then relaxed. Mitchell led him back into the hall. "I'm no psychiatrist," Mitchell said, "but I think she wants Macklin stupid. Prefers it that way. She's always dominated his personal life, and now she can dominate him completely." "What is she? A monster?" the Army officer muttered. "No," Mitchell said. "She's an intelligent woman unconsciously jealous of her husband's genius." "Maybe," Carson said. "I don't know. I don't know what the hell to tell the Pentagon. I think I'll go out and get drunk." "I'll go with you," Ferris said. Mitchell glanced sharply at the little biologist. Carson squinted. "Any particular reason, doctor?" "To celebrate," Ferris said. The colonel shrugged. "That's as good a reason as any." On the street, Mitchell watched the two men go off together in bewilderment. IV Macklin was playing jacks. He didn't have a head on his shoulders and he was squatting on a great curving surface that was Spacetime, and his jacks were Earth and Pluto and the rest of the planets. And for a ball he was using a head. Not his head. Mitchell's. Both heads were initialed "M" so it was all the same. Mitchell forced himself to awaken, with some initial difficulty. He lay there, blinking the sleep out of his eyes, listening to his heart race, and then convulsively snatched the telephone receiver from the nightstand. He stabbed out a number with a vicious index finger. After a time there came a dull click and a sleepy answer. "Hello?" Elliot Macklin said. Mitchell smiled to himself. He was in luck; Macklin had answered the phone instead of his wife. "Can you speak freely, doctor?" Mitchell asked. "Of course," the mathematician said. "I can talk fine." "I mean, are you alone?" "Oh, you want to know if my wife is around. No, she's asleep. That Army doctor, Colonel Sidney, he gave her a sedative. I wouldn't let him give me anything, though." "Good boy," the biologist said. "Listen, doctor--Elliot--El, old son. I'm not against you like all the others. I don't want to make you go back to all that worrying and thinking and headaches. You believe me, don't you?" There was a slight hesitation. "Sure," Macklin said, "if you say so. Why shouldn't I believe you?" "But there was a hesitation there, El. You worried for just a second if I could have some reason for not telling you the truth." "I suppose so," Macklin said humbly. "You've found yourself worrying--thinking--about a lot of other problems since we left you, haven't you? Maybe not the same kind of scientific problem. But more personal ones, ones you didn't used to have time to think about." "If you say so." "Now, you know it's so. But how would you like to get rid of those worries just as you got rid of the others?" Mitchell asked. "I guess I'd like that," the mathematician replied. "Then come on over to my laboratory. You remember where it's at, don't you?" "No, I--yes, I guess I do. But how do I know you won't try to put me back where I was instead of helping me more?" "I couldn't do that against your wishes. That would be illegal!" "If you say so. But I don't guess I can come anyway. The Army is watching me pretty close." "That's alright," Mitchell said quickly. "You can bring along Colonel Carson." "But he won't like you fixing me up more." "But he can't stop me! Not if you want me to do it. Now listen to me--I want you to come right on over here, El." "If you say so," Macklin said uncertainly. * * * * * Mitchell opened the door on the first knock. Macklin stood in the doorway, looking uncertain and ill at ease. Carson stood behind his left shoulder, looking actively belligerent. "Come in," Mitchell said. "I have the injection ready for you, Doctor." "Now you aren't going to 'cure' me?" Macklin said in concern. "This is just going to help ease my mind?" "Of course," the biologist said soothingly. Colonel Carson lunged forward, mouth opening ominously. Mitchell winked at him broadly. Carson stopped in confusion and studied Mitchell's face. He essayed a second wink. Carson relaxed. Mitchell picked up the hypo of colorless carrier fluid from the interestingly stained work table. "One thing first, Dr. Macklin. I'll have to have your signed release for this treatment. It specifies that your intelligence will probably be affected in this effort to keep your head from troubling you. Carson can witness it." "Sure," Macklin said. "I guess that's okay. If you say so." The colonel grinned, his face hot and shiny. "I'm sure it will be fine, Doctor." Macklin looked at the officer with almost a trace of suspicion, then accepted the sheet of typescript and the ballpoint pen from Mitchell. Laboriously he affixed his signature. Mitchell had the mathematician take a seat and pressed the needle directly into the neck area. "Ouch!" Macklin said. Mitchell stood back and exhaled. "It should take effect shortly," the biologist said. "Good," Carson said.... The cylinders of the electric clock said 4:35:00 A.M. Macklin was playing with his hands and their shadows in front of his face. "How long will this stage last, Dr. Mitchell?" Colonel Carson said in concern. "Indefinitely. This is the last stage. The circulatory system of his brain has been relaxed to the point where he has about the I.Q. of a turnip." Carson steeled himself. "_So_, doctor! You're nothing but a dirty Lux!" "No, Colonel. I've never even seen Luxemburg. My reason for doing this to Dr. Macklin were entirely patriotic ... or, at least, sympathetic." "Tell that to the hangman! I'll see you tried for treason." "Look at him, Colonel. He is certainly no longer legally responsible. He has the strength of a grown man and the intellect of an amoeba. It would be impossible to keep him alive either under sedation or in a padded cell. Even if Mrs. Macklin still refuses her consent--and I don't think she will when she sees him in this bad a state--you can go over her head and get permission for Ferris and myself to administer our antitoxin to destroy the pituitrin-absorbing virus colony in his cerebrum." Carson looked dazed. "I--I'll call her." * * * * * Mitchell greeted the orangish sunrise with a feeling of defeat. He turned from the window to face the instruments of his laboratory. Mrs. Macklin had come. Numbly she signed the release allowing the restorative treatment. By the time she, Carson and the mathematician left, Macklin had been able to say "mama" and--embarrassingly--"papa" to him. Mitchell was confident he would regain his full senses and that the brain cells had only become passive, and had not decayed. But still it was only the wiping out of one horrendous mistake. Months and months of work wasted. The door banged open and a small man entered with a long, slender brown paper bag and proceeding on an aeronautical search pattern. "Dr. Ferris!" Mitchell said. "You mustn't take it so hard. I tried to get in touch with you. But at least I have been able to administer the antitoxin to Dr. Macklin." "Who gives a damn about that egghead?" Ferris said, placing the paperbag upright on the work table. "Don't you understand, man? We're rich! Where are the glasses?" "Rich?" Mitchell said. "Doctor, would you like me to help you over to your own quarters?" "Relax, Mitchell. I'm not _that_ drunk. I know what I'm talking about. I tell you the F-M Virus is going to make us rich! Powerful! Men like Elliot Macklin will be insignificant beside us." He knew that Ferris was in sober earnest. "What do you mean, Doctor?" Ferris turned, his thin face lit up with a flush of pleasure. "Mitchell, we have something to make people permanently stupid! People can stop thinking temporarily by using alcohol or narcotics or watching television. But we--only you and I--have something to let them stop thinking permanently. And we'll make them pay for it--for the shot and the rent on the condition. Who _wants_ to think? A handful of people. Who _has_ to think to do routine paperwork or push a button or pull a lever? A bunch of happy, content morons can do all of that. We'll return man to his natural, pre-evolutionary state of stupidity. As for those of us who _don't_ take the treatment, we have it made! Made!" Mitchell stared at him. "Don't you get it, Mitchell?" Ferris roared. "_We have the ultimate tranquilizer!_" Mitchell thought of the world after the F-M Virus had been given it. He thought: In his condition, if I shoved Ferris so that his head cracked into the corner of the table, no one could prove anything. I could destroy our records.... No, it wasn't any good. Some other researcher somewhere else was bound to isolate the F-M Virus. None of it was any good. He groped blindly towards the door. He had to get out, get to a drugstore, buy some aspirins. His head was killing him. 
61367	----	ANOTHER EARTH BY DAVID EVANS & AL LANDAU Whatever it was that had happened in the test, it badly needed a good explanation. [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, May 1963. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] I Lieutenant Colonel Philip Snow, Flight Surgeon, USAF, and Test Director of the Aero-Medical Laboratory, was pacing the study floor in his quarters, asking himself for the dozenth time in the past half-hour: What had happened to Richardson during the test that afternoon? He was no stranger to problems. He had been living with them for the past few years, and they had been problems the like of which had never before challenged the ingenuity of man. For he was the head of a small community of men, scientists like himself--medical specialists of all kinds, psychologists, electronic technicians, physicists, pressure engineers, mathematicians and so on, each one of them an acknowledged expert in his particular field--who had worked together with one end in view: to send a man into space and bring him back safely to Earth again. To put it more excitingly: to enable man to take his first step toward the conquest of the universe. The result of their labors to date was the Capsule, a bottle-shaped contraption which occupied the center of the laboratory floor. It wasn't very big; just big enough to contain a man enclosed in a spacesuit, lying on a couch surrounded by instruments. But there wasn't a square inch of the capsule itself, the spacesuit, and the instruments which hadn't presented innumerable problems, the solving of which had been the result of endless research and theorizing and testing. And in the same way, and almost to the same extent, there wasn't a square inch of the man, too, which didn't present problems, all of which must be solved before he could be sent into space. And so, in test after test, one of the chosen astronauts had lain on the couch in the capsule, wired through his spacesuit to the dozens of dials and graph recorders on the consoles at which sat the watching specialists. It seemed there was nothing that could happen inside his body that they could not know about. They could read every flexing of his muscles, every heartbeat, every tiny shifting of temperature, every reaction of his blood and of his complicated nervous system. On the encephalograph, they could even detect reactions in the mass of gray matter which was his brain, any sign of tension there, and above all, any symptom of that strange phenomenon of which so little was yet known, and which was called the "breakoff"--the eerie sensation of complete isolation from Earth, the trancelike apathy and indifference to survival that can attack not only high-flying pilots, but deep-sea divers, "the rapture of the depths," and sometimes it was accompanied by hallucinations in which strange forms and sounds were seen and heard. * * * * * In the case of Lieutenant Hamilton Richardson, USN, there had been no mysterious troubles of this kind--in fact, no troubles of any kind at all. Aged thirty-six, he had been one of the first of the astronauts to volunteer. He had passed with flying colors every one of the grueling preliminary tests, mental and physical, and as far as could be judged by science, he had seemed to be the perfect specimen, mentally and physically, for the job. In the many tests made with him inside the capsule, nothing had gone wrong with him. There had been no signs of fatigue or failure of any kind. Had Snow been asked who, in his opinion, would be the first man--or, at any rate, the first American--to go into deep space, he would unhesitatingly have nominated Richardson. That is to say, until that afternoon when the thing had happened. It had been a long test, one made for the first time. The object of it was to find out how the spacesuit, which was sealed off from the rest of the capsule, would stand up if something happened to the capsule itself. If, for instance, in its headlong flight through space, something struck it, something, maybe, no bigger than a small pebble. The odds were that in collision with even so small a meteor, the shell of the capsule would be punctured, and within a minute or less, the atmospheric pressure inside it, fixed at about five thousand feet above sea level, would be reduced to zero. In other words, the capsule would become a vacuum in which nothing on Earth could live. The astronaut would then have to depend upon his spacesuit which, being pressurized, and being really a capsule within a capsule, with its own supply of oxygen, would be the one hope of survival. That day, the test had consisted of the "puncturing" of the capsule. At a given signal, the pressure inside it had been reduced to that of fifty miles above the Earth's surface--in other words, to zero--by pumping out the air inside it. Richardson, the ace of the astronauts, had been chosen for this important test. It had gone well. With the other scientists at their dials, Snow, seated at the big console of literally dozens of dials, the only one to be connected with Richardson by sound and speech, had given the signal. In a minute, the capsule had become a vacuum fifty miles above the surface of the Earth, outside its envelope of atmosphere. Richardson's voice, reading his instruments, acknowledging Snow's instructions, answering his questions, had come through as normal and as calm as ever. Snow had felt a rising excitement as the test proceeded. And then, without warning, the thing had happened. Richardson's voice had stopped in the middle of an instrument reading, as if it had suddenly been cut off. A few seconds later, it had resumed. But when it did so, the voice was uttering a stream of unintelligible sounds in a low, lilting chant. Snow had listened incredulously for perhaps thirty seconds, at the end of which the sounds had suddenly ceased. Immediately, Snow had given instructions for the normal pressure inside the capsule to be restored. Almost as he had done so, Richardson's voice, once again normal, had resumed the reading of the instruments, taking up from where it had left off a minute before. Acting on a sudden impulse. Snow had decided to say nothing over the wire to Richardson at the time. He had continued his conversation with the astronaut, telling him they were "bringing him down" and asking the usual questions until the test ended. * * * * * When, with the others, he had stood around watching while Richardson was helped out of his spacesuit, he had carefully watched their faces, looking for some sign of doubt or puzzlement. But he saw none. On the contrary, they all seemed triumphantly satisfied. Even Richardson had shown no sign that anything unusual had occurred. He had been his usual cheerful self, seeming not even slightly fatigued by the long test. Being the only one who had been in contact with Richardson, Snow had suddenly found himself wondering if he really had heard those sounds, if, maybe, he had been the victim of a hallucination. This was why he had said nothing about it at the time. He had just asked, as casually as he could, if any of them had anything they wanted to bring up immediately. They had shaken their heads, beaming their satisfaction, and he had dismissed them all, saying that in view of the length of the test they might all call it a day, and postponing the usual interrogation until the morrow. Then he had hurried back to his quarters, bringing with him the recording machine on which, as was the practice, his conversation with Richardson during the test had been recorded. Controlling his impatience with difficulty, he had rewound the tape on the machine and played it back, the tension rising within him as he listened. There had been no hallucination. He heard Richardson's voice reading the instrument, the sudden cut-off in the middle of it, the short silence, then the voice uttering the strange sounds in a low-pitched chant with a gentle rise and fall to it. Three times he had played it back, and now it seemed to him that these were not just disconnected sounds. They appeared to have a cadence, a phrasing which indicated that they belonged to a language of some sort. Snow was no linguist. He had less than a fair conversational knowledge of French and German, and a scholar's acquaintance with Latin, but he had travelled very extensively in his time and had been accustomed to hear many languages spoken. He was quite sure he had never heard anything even remotely resembling these sounds. Certainly Richardson was no linguist either. He was third-generation American from British stock, and all he knew about languages was what he had learned in school. * * * * * Then where had those sounds come from? Were they a language, and if so, what did they mean? How could this happen to a man like Richardson without his knowing about it? Did it mean that here was, after all, something strange about him which the man himself might not even know about, and which might mean that he was not fit for the project? This last question worried Snow more than the others. He went to the telephone on his desk and dialed the Richardson bungalow. The voice of Richardson's pretty wife answered him. "Yes? Sandra Richardson here." "Hello, Sandra. Phil Snow calling. Is Ham there?" "He's in the shower singing his head off. Shall I get him?" "No, it isn't important. I just wanted to ask him again if he feels all right after the test. It was rather a long one, and I wondered if he might feel tired, or...." "Tired? He seems even more full of pep than usual. Was the test so very long, then?" "Yes, it was. That's why I called and--just to tell him it was a success. I haven't checked all the reports yet, but it looks good. And you say he's as usual?" "Yes. Why? There wasn't anything...?" "No, no, nothing at all. Just as I said. I'll be seeing you." He rang off, hoping that nothing he had said was now making Sandra Richardson suspicious, and resumed his pacing up and down the floor. Now another question came into his mind. The same test would be run several times again before final conclusions could be made. Should he wait for them to see if this thing happened again before starting anything with Richardson and his colleagues? But even as he asked himself the question, he knew the answer. If this never again happened in any future test, the fact would remain that it had happened once and could not be forgotten or brushed aside. It must be cleared up. Something had happened to Richardson's mind. He decided to take Abe Franstein, his head psychologist, into his confidence. As he dialed Franstein's bungalow, he recalled with a sense of comfort that the brilliant little man was not only a world authority in his particular subject, but that he was said to be able to read, write, and converse in a staggering number of languages, some of them obscure Oriental dialects. When Franstein answered the call, Snow asked him to drop in for coffee after dinner. II "Well, I must say," said Franstein as they sipped their coffee, "yours is the first glum face I've seen around here since that test this afternoon. Here we are, within sight of our goal at last, and look at you! Weren't you satisfied?" "Before I go into that," Snow replied, "there are a few things I want to ask you." "About the test?" "In a way, but principally about Richardson. Have you ever had any reason to suspect that there is anything unusual about him?" "In what way?" "In your line." Franstein produced an enormous meerschaum pipe and proceeded to fill it from an untidy plastic pouch as he replied. "Yes, there is. One very unusual thing." "There is?" "He's got a very rare type of mind. It's probably perfectly balanced." The little man lit his pipe and continued: "The vast majority of us have some sort of imbalance, mentally. He hasn't. When I say imbalance, I mean the sort of thing that makes for genius, a phenomenal memory, an outstanding, effortless talent, amnesia, any form of insanity, or even something like a violent temper. Anything, so to speak, overemphasized." "Is it physical? I mean, does it have anything to do with the size or weight of the brain, or anything like that?" "You can take the brain of a genius and that of an ordinary person of average intelligence, and find them exactly the same in measurements and tissue condition. The popular conception of the genius as a man with a bulging forehead is so much nonsense. Plenty of lunatics and retarded individuals have bulging foreheads." "Then what does it have to do with?" "Ah! That's the big question. Nobody knows. You can take two men, equal physically in every respect, equal in upbringing, education, health, and with the same sized brain. One of them might turn out to be a genius, the other an average individual, and nobody knows what makes the difference. Nobody knows what makes an infant prodigy, or what it is which enables a child of two to read easily, or a kid of five or six to play some instrument as if he'd been at it for years or compose symphonies, or master advanced mathematics. Same answer. Nobody knows. It's got nothing to do with heredity. So few geniuses have had genius offspring that they form exceptions to the rule. Again, why does an infant prodigy sometimes lose his gift or talent entirely as he grows older? We don't know. All we know is that the gift or talent is there, but where it comes from, or why it is in one brain and not in another, we don't know. But surely you don't have to have me to tell you all this, Phil? What's on your mind?" "Listen to this," Snow said, and went to the tape recorder. * * * * * He rewound the tape to its beginning, depressed the switch marked _Play_, and presently they heard the two voices, Snow's and Richardson's. "Now!" said Snow as the point on the tape approached. There came the sudden stopping of Richardson's voice in the middle of an instrument reading, the short silence, then Richardson's voice chanting the strange sounds. Franstein took his pipe from between his teeth and his mouth fell open as he listened. The sounds ceased and Richardson's voice resumed the instrument reading at the point at which it had left off. "That's all," said Snow, and switched off the machine. Franstein put his pipe back into his mouth. "Is this the recording of this afternoon's test?" "Yes. What d'you make of it?" "Let's hear it again." Snow played back the recording a second and a third time, and then said: "Well?" Franstein went to the table and helped himself to more coffee before replying. "It's a new one on me," he said presently. "I've got about a thousand recordings of languages and dialects from all over the world, and not one of them is anything like that." "You think it is a language, not just sounds?" "That we've got to find out, but I'd say, offhand, it's a primitive form of a language of some sort." "Then how the devil does it come out of a man like Richardson who's never spoken anything but English--nor his forebears, for that matter?" Franstein shrugged his shoulders. "How does great music come out of a child of six, and so on? Same question, same answer. Nobody knows. Have you spoken to Richardson about it?" "No. I rang his bungalow just before dinner and spoke to Sandra. Richardson was in the shower, and she said he was feeling fine. I didn't tell her about this, of course." "Then it couldn't have been some sort of mediumistic trance. They usually feel the effects of that sooner or later." "You're not suggesting spiritualism, are you?" and in Snow's voice was a note of amusement. "Don't laugh at it. If it's never been proved, neither has it been disproved." And that touched off a discussion which went on for two hours. It covered many theories, many beliefs and faiths, all of which Franstein spoke learnedly and with great respect. He talked of reincarnation, spiritualism, the mystery of time, and in this last connection, he paused in the middle of what he was saying and asked: "If this--" and he waved a hand toward the machine--"is a language, and I'm pretty sure it is, how can we be sure that it is a language of the past? Why shouldn't it be one belonging to the future? All languages change with time. We'd probably find it very difficult to understand the English spoken ten centuries ago. What if this is the English that is going to be spoken a thousand years hence?" * * * * * To all of which Snow listened with the skepticism of the exact scientist, and Franstein, quick to notice this, went on: "You think yourselves clever, you exact scientists, and so you are. You can do a lot of things. You can split the atom, measure the stars, estimate the life expectancy of the sun; you have conquered distance, you have surrounded us with miracles like radio, television, invisible rays and all the rest of it. Presently, you will conquer space and colonize the planets, and so it will go until it will seem to you that you will know everything. And you will too, except for one thing--the one final mystery, the last secret of the universe--MAN. And that means you and me, and any human being from a bum of Skid Row to the President. Man is the eternal unknown quantity, and you've never had a more clear demonstration of this than what happened to Richardson this afternoon. Oh, I know what you've found out. You know all about man, his insides, his glands, muscles, nerves, brain, and so on. You can even display him on a table as a bucket of water and little piles of salts and minerals, and you can point to them and say: 'That is what man is made of.' Only the other day I was reading about some scientist who thinks he's on the verge of producing a cell of life in a test tube. You may even do that, and you may find out one day how to put the water and the salts and the minerals together again and make a man. I've always thought the Frankenstein story was a bit of inspired prophecy. But you still won't be able to explain why great music can come from a child of six, or what happened to Richardson this afternoon." He lit his big pipe, which had gone out, and through the puffs asked: "And what do you propose to do about Richardson?" "Run the test again tomorrow with him and see if this happens again, and then decide," replied Snow. "But even if nothing happens tomorrow, you can't ignore this." "That's true. We've got to get to the bottom of it, and that's where you come in. You're the expert on this sort of thing." Franstein looked at his watch. "Let's sleep on it and see what happens tomorrow, eh?" He was on his way to the door when the telephone bell rang. Snow picked up the receiver, and he heard him say: "Sandra?... _What?_... I'll be right over. I've got Abe Franstein with me. I'll bring him with me. Don't worry dear." Snow hung up. "Something's happened to Richardson," he said. "He's gone into a deep sleep and won't wake, and he's talking to himself in some funny language. Let's go." Snow rummaged in a drawer of his desk and found a stethoscope. III Five minutes later, they were standing with pretty Sandra Richardson at the foot of the bed on which Richardson, clad in his pajamas, sprawled on his back. He was in a deep sleep and from his mouth came a low chanting. Franstein and Snow glanced at each other as they recognized the sounds. Snow tried to wake the astronaut, gently at first, then less so, but it had no effect. He used his stethoscope on heart and lungs, drew back an eyelid and examined the eye beneath, felt the brow. "When did this happen?" he asked the anxious Sandra. "About fifteen, maybe twenty minutes ago," she replied. "We came in here and undressed and I used the bathroom first. When I came out, I found him like this." "How's he been all the evening?" "Fine, just as I told you when you rang. Tom and Betty Moreland came for dinner and we played canasta. Is he all right?" "As far as I can see, yes. Heart, lungs, eyes all right, no fever. I guess we'll just have to wait till he wakes." They went into the sitting room and Sandra left them to make coffee. "He's living through something," Franstein said. "Pity you haven't got the recorder here." "I thought the same. I'll get it." Snow left and Franstein wandered back into the bedroom and leaned over Richardson. Now he was sure this was a language and that the sleeper was conversing with someone in his sleep. The expressions changed on Richardson's face rapidly as they do on the face of anyone during a conversation. At one moment he laughed as he said something, then became serious as he said something else. Sandra came into the bedroom and joined Franstein at the bedside. "He's never been like this before," she said worriedly. "Doesn't he ever talk in his sleep?" "He never even snores. When we were first married, he slept so quietly that I thought he'd stopped breathing, but I'd only have to touch him or whisper to him and he'd wake in an instant. What does this mean?" "We'll find out, never fear." They went back into the sitting room as they heard Snow return. He was carrying the recording machine, and seeing the question in Sandra's eyes as she saw it, he said reassuringly: "We're going to make a recording of what Ham's saying. We'll soon find out what this is all about." He busied himself changing the tapes on the machine, taking the new one from his pocket, and fumbled the job in his haste. He had plugged in the microphone and was unwinding the long chord when they heard Richardson's voice call out from the next room: "Sandra!" and a moment later, Richardson appeared in the open doorway, staring at them in astonishment. "Abe! Phil! When did you come here?" "About half an hour ago," Snow replied. * * * * * Richardson passed a hand over his eyes. "I must have fallen asleep," he said. "You did, darling, and I couldn't wake you," Sandra said. "So I called Phil." "You couldn't wake me?" "No, and you were talking away in your sleep. You had me worried." "Why?" Sandra, at a loss, looked at Franstein and he answered for her. "You were dreaming, Ham," he said. Richardson thought for a moment before replying. "Now that you mention it, I was. But what's so extraordinary about that? Why are you all looking at me as if I'd suddenly grown horns? "D'you remember what the dream was about?" Franstein asked. "Vaguely. Yes, I do. It was just a dream. Why is it so important?" He sat down in a deep chair and looked around at them. "What is all this?" he said. "I fall asleep for half an hour, have a silly dream, and wake up to find you here looking as if something big has happened." "Something has happened, Ham," said Franstein. "Something we don't understand." Richardson started up in his seat. "Take it easy, there's nothing to worry about. We'll get to the bottom of it." He turned to Snow. "I think I know the way out of this. Play the recording for Ham to hear." Snow hesitated for a moment. "All right, if you think so," he said, and busied himself with the recorder, replacing the used tape on the spool. Sandra perched herself on the arm of her husband's chair and put an arm about his shoulders. They waited while Snow linked up the end of the tape to the other spool. He pressed the _Play_ switch, and presently there came the voices of Snow and Richardson. "That's this afternoon's test," Richardson said. Franstein nodded, and they continued to listen. Then came the chanting sounds, and when he heard them, Richardson's expression changed to one of amazement. Snow switched off the machine. "What was that?" Richardson asked. "We hoped you'd be able to tell us," Franstein replied. "I? What should I know about it?" "That was your voice, Ham. Nobody's touched the tape, and I heard it during the test." "But this is crazy. How could I make a noise like that without knowing anything about it? Why, I remember every second of that test, and I know I didn't do anything like that." He jumped to his feet and began to walk up and down the room, his hands pressed to his head. "I said take it easy, Ham," Franstein said. Richardson pulled up short in his pacing and turned to the little man. "How can I take it easy? I spend six hours in the capsule in a difficult test, remember every bit of it, come out of it feeling not even tired, and now you tell me that in the middle of it I had some sort of a blackout and made funny noises. That can only mean that there's something wrong with me, and you don't have to tell me what that means. I don't qualify, after all. Is that what you came here to tell me?" * * * * * Franstein's voice was as quiet as before. "It doesn't mean anything of the sort. If there'd been a blackout or if something else had happened to your brain, it would have shown up on the encephalograph, and nothing showed. I didn't know about this until I heard the recording, and we weren't going to say anything about it until we'd run the test a second time. Then Sandra called us to say she couldn't wake you and that you were talking in your sleep, and we came over to find you in a sleep as deep as a coma and obviously dreaming." "And what's that got to do with the test?" "You were making the same sort of sounds in your sleep as you did in the test, and I'm sure they add up to a language of some sort." "_What?_ You mean to say that was a language? For Pete's sake, I've never spoken anything but English all my life. I can't." "We know that." Richardson turned to his wife. "Is this true?" he asked her tensely. "Was I making noises like that in my sleep?" She nodded miserably. He threw up his hands. "Okay," he said, "you're three to one. The ace astronaut turns out to be some sort of nut who talks monkey language in his sleep, and when he's awake too, without knowing it." He went to the deep chair and slumped down into it. "What do we do now? Go into analysis again? Start all over?" He laughed shortly and bitterly, and added: "Or do I resign from the project?" "Listen, Ham," Franstein said. "We're up against something new, something I don't understand, and whatever happens, we've got to try and find out what it is, for your sake as well as for the project's. Let's relax and start with the dream. Tell us what you remember of it." Richardson took time to calm down before he spoke. "It was just a dream," he began presently. "There was a big spaceship and a lot of people standing about." "Where was this?" "Where? I don't know. On Earth, I suppose. Open place, you know, only...." He paused before going on. "Only it wasn't standing up on end like a rocket. It was lying on its side, and we were loading it." "Who were 'we'?" "My father and my two brothers. And that shows how silly the dream was because I haven't got any brothers or father. My father in the dream wasn't anything like my own. He was just an old man, and he told us where to stow the crates." "What was in the crates?" "In the crates?" Richardson looked up. "Let me see now. Oh, yes, they were full of the seeds of plants and eggs and sperm of animals--sort of the beginnings of things." "And where was the ship going to?" * * * * * Again, Richardson concentrated before replying. "To another Earth," he said. "That's right. The old guy, our father, said that this one was going to be destroyed by some disaster, and the people standing about were laughing and jeering and saying the old man was crazy." "Do you know what sort of disaster was going to happen?" asked Franstein. Richardson looked at him and suddenly a smile formed on his face. "Now I know where that dream came from," he said. "Remember that book _On The Beach_? The story about how everyone on Earth was wiped out by nuclear fallout? That's it! I remember wondering when I read it if some of us would be able to go to another planet before anything like that happened here, and I remember thinking, too, that we'd probably take things like seeds and so on with us, and even the ova of animals, and that by then we'd probably know how to preserve them--freeze them or something of the sort." "We can do that now," Snow said. "Well, there it is, then," said Richardson, smiling again. "There's the explanation." "It explains the dream all right," agreed Snow, "but what about the sounds? Particularly those you made in the capsule?" "Lord, yes!" said Richardson, and the smile left his face. "I'd forgotten about those. That puts us back to where we came in, doesn't it?" "I'm not so sure," said Franstein. He got to his feet and, in his turn, prowled up and down the room, deep in thought. The others waited for him to go on, and presently he turned to them, a glint of excitement in his eyes. "I think we're onto something," he said. "Those sounds are obviously a part of your dream, Ham, including the ones you made in the capsule, and only you know what they mean." "But I don't even remember making them!" "No, but your mind does. If we can unlock your mind, we can find the secret, and there's a way in which it can be done. Hypnosis." "Hypnosis?" The others spoke at once. Franstein nodded. "I've got to put you into a hypnotic trance, Ham, and we'll play that recording back to you and I think--only think, remember--that you're going to be able to tell us what they mean. Any objection, Phil?" "You're the expert." "How about you, Ham?" "I'll do anything to clear up this business." He jumped to his feet. "Let's get on with it now. What do I do? Shall I lie down on the sofa?" "I didn't know you are a hypnotist too, Abe," said Snow. "I'm not surprised, though. I might have known." Franstein took no notice of this. He stepped up to Richardson and looked up at him, holding out one hand which the other, wonderingly, took. "The big thing is confidence, Ham," he said, looking up earnestly. "Complete confidence. You have that in me?" Richardson looked down on the little man and nodded his head. "Sure," he said. "I've always had that in you, Abe." Franstein continued to hold the other's hand. "That's fine," he said. "All you have to do is to relax and trust in me. Just relax completely. Just let yourself go--eh?" * * * * * Richardson's head nodded again, and for a moment Franstein, still holding the hand continued to look up into Richardson's face above him. Then he released the hand and said: "Now you can lie down on the couch if you like." Richardson went to the couch and stretched himself out on it. "I've heard a lot about this," Sandra said, "but I've never seen it done." Franstein smiled at her. "You've just seen it done, my dear," he said, and as she stared back at him in astonishment, added: "He's a very good subject. Now, when that machine is ready...." "If I'm right in what I think," Franstein said a few minutes later to Snow, who stood by the table on which now rested the recorder, and to Sandra who was at the head of the couch looking down on her husband who lay there, his eyes half-closed, "you're going to hear something very surprising. Please don't make a sound." They nodded their heads, and Franstein seated himself on the edge of the couch, leaned over Richardson, and spoke softly: "You hear me, Ham?" "Yes, I hear you." "Then listen." Franstein turned and nodded to Snow. The machine was switched on and there came, clearly, the chanted sounds of the test. They finished and the machine was switched off. "You heard, Ham?" "Yes, I heard." "You made those sounds that we just heard." "Yes." "Can you repeat them?" "Yes." "Then do so." And now the strange low chanting sounds streamed from Richardson's lips. Sandra put her hands to her mouth to stifle a gasp. Snow stepped to her side, his face tense. The sounds ceased and Franstein, his eyes alight with excitement, said softly: "Tell us, to whom are you speaking?" "To my sons." "Tell us in English what you are saying to them." There was a silence. Franstein repeated his command, and Richardson spoke again, this time in his normal voice. "_And God saw the earth, and behold it was corrupt; for all flesh had corrupted their way upon the earth. And God said to Noah, I have determined to make an end of all flesh; for the earth is filled with violence through them; behold I will destroy them with the earth. Make yourself an ark ... and you shall come into the ark, you, your sons, your wife, and your sons' wives with you. And of every living thing of all flesh you shall bring two of every sort into the ark to keep them alive with you, they shall be male and female.... Also take with you every sort of food that is eaten and store it up.... And Noah did all that the Lord had commanded him._..." The voice tapered off into silence, and Sandra, her eyes wide with fear and amazement whispered: "That's the story of the Flood and he told it as if he was there. What does it mean?" Franstein silenced her with a gesture and bent over Richardson whose eyes were closed. "Ham," he said, a note of insistence in his voice, "you hear me? Answer!" The eyes half opened. "Yes, I hear you." "Tell me, where did you go in the ark?" "To a place of many waters ... many waters, and we rested on them until they went down." Now the voice was fading. "Where was it? Tell me, where was it?" The reply came in almost a whisper. "I don't know. It was another earth ... another earth...." The eyes closed again, the breathing became deeper, but the lips still moved, and through them, barely heard in the tense silence, came again the low, chanting sounds. Then they, too, died away to silence, the lips ceased to move, and Richardson slept.