Oak Street ^ JMBOLDT LIBRARY. no.82 UNCLASSIFIED , $1,50 a year (12 numbers). Entered at the A r ew York Post Office as Second-Class Mail Matter. ILLUSIONS OF THE SENSES : AND OTHER ESSAYS. BY RICHARD A. PROCTOR. ft$U*A New Volume of the HUMBOLDT LIBBAR Y is now ready , comprising Nos, 71— SO inclusive. Price , cloth, $1,75, THE CELEBRATED PIANOS. SOHMER PIANOS. ABE AT PBESENT THE MOST POPULAR AND PREFERRED BY THE LEADING ARTISTS. Musical authorities and critics prefer the 66 SOHJIER ” Pianos, and they are purchased by those possessing refined musical taste and appreciating the richest quality of tone and the highest perfection generally in a Piano. THE SOHMER PIANOS ARE USED IN THE FOLLOWING INSTITUTIONS: N. Y. College of Music; Vogt’s Conservatory of Music ; Villa Maria Convent, Montreal; Villa de Sales Convent, Long Island ; N. Y. Normal Conservatory of Music ; Philadelphia Conservatory of Music, and most all the leading first-class theatres in NEW YORK AND BROOKLYN. Received First Prize at Centennial Exhibition, Philadelphia, 1876. Received First Prize at Exhibition, Montreal, Canada, 1881 and 1882. SOHMER & C O., MANUFACTURERS OF GRAND, SQUARE AND UPRIGHT PIANOFORTES. Warerooms, 149, 151, 153 & 155 East 14th Street, N. T. S. FITZGERALD, PUBLISHER, 108 CHAMBERS STREET, ,\ ! EW YORK. ABANDON PHYSIC! GLUTEN SUPPOSITORIES CURE CONSTIPATION AND PILES. m. cnflw^r from Ponstmation and Piles should test the GLUTEN SUPPOSITORIES which* cure mosifas^ by' INCREASING THE NUTRITION OF THE PARTS, thus inducing desire and 8tre i) g R h A ni W Thompson, °N ortham pt on , Mass., says: * I have tested the Gluten Suppositories, and consider them valuable, as, indeed, I expected from the excellence of then theoiy. C ° nf I)iL r WM. r ToD HELMUTH declares the G!uten Suppositories to be “ the best remedy for constipa ti°n wWo^Ihave > everprm!ribed.ep > s OSayI o, JO ur Oluten Suppositories: God bless the ma»»ho. thiented tljem^a L. Rj^lky. BuHHigori^Vt.00^ Oompai)y . Gluten Suppositories, as they have KtfSSSSd substantia! relief through the use of the Gluten Suppositories -Cyrus Bradbury, Hope 4ale fe*0 Cents by Mail. Circulars Free. HEALTH FOOD CO., 4th Avenue and 10th St., N. Y, JOURNAL of MICROSCOPY AND NATURAL SCIENCE Is published quarterly in London, on the first days of January, April, July and October. The Journal contains 64 pages of letterpress, octavo size, with woodcuts- and numerous full-page lithograph plates. While Microscopy occupies the most prominent place, the Journal always contains valuable articles on several branches of Natural Science as Botany, Entomology, Geology, Photography, etc. Subscription price $1.75 per year. The Journal and the Humboldt Library for one year only $ 3 . 00 . Agent for the United States : J. FITZGERALD, 108 Chambers Street, New York. TWO VALUABLE WORKS ON MUSIC. By ISAAC L. RICE, LL.B., Lecturer in Columbia College , New York. I. What is Music? Price, cloth, 50 cents; paper 25 cents. Evening Post , N. Y.— “ Cannot fail to fascinate those who are fond of music, or of contemplating the laws which in the works of nature are seen in full operation.” II. How the Geometrical Lines Have their Counterparts in IV^tsic. Price, paper, 12 cents. Evening Ma^- N. Y “ Manifests subtle thought and a keen perception of the deep foundation on which music rests.” As these works ari6 not for sale by the book trade, orders should be sent direct to J. FITZGERALD, I 108 Chambers Street, N. Y. \VV ILLUSIONS OF THE SENSES: AND OTHER ESSAYS. By RICHARD A. PROCTOR. ILLUSIONS OF THE SENSES. Professor Le Conte of the Cali- , fornia University has recently pub- - - lished in the North American Review ' an interesting paper on the Evidence of the Senses, in which he shows that ; on the one hand the senses often \ afford most incorrect information j> while on the other the powers of such ? scientific instruments as give exact r ' information would be utterly unsuit- able substitutes for our less exact senses. Sight tells us that an object - is flat when it is round, touch that an object is double when it is single, hearing that sounds come from close by when they really reach us from a great distance ; but on the other hand to have eyes with telescopic power, or fingers as sensitive as a chemist’s balance, or ears with the sound-gathering qualities of the micro- phone, would unfit us for the kind of life we have to lead upon this work-a- day world of ours. I propose now to discuss the ques- tion dealt with by Le Conte, with special reference to the liability of our senses to various forms of error. Taste and smell need not here occupy our attention. They are less used than the other senses in scientific re- search ; and so far as the purposes to which they are chiefly directed are concerned they are in the main trust- \ worthy. They may deceive us by presenting as pleasant what is really deleterious, but once experience has determined the qualities and effects of substances having such and such taste or odor, we are not Often de- ceived in identifying those substances thereafter. The sense of touch is commonly understood as including the sense of heat-effects. But here, as Reid long since pointed out, our division of the senses is unsound. Undoubtedly the sense of touch is entirely distinct from the sense of heat, — though we may be said to feel in both cases, The error probably arose from the circumstance that the same organs seem employed in noting the effects of contact and the effects of heat. I touch a surface to see if it is hard or soft, rough or smooth, just as I touch a surface to see if it is hot or cold ; moreover there is no part of the body which is sensible to the effects of contact which is not also sensible to the effects of heat and cold. But we recognize a marked difference be- tween the sense of touch when the tip of the tongue is employed for the moment as the organ of touch, and the sense of taste ; yet the difference between taste and touch is not more marked than the difference between heat and touch. Therefore in dealing with errors 2 ILLUSIONS OF THE SENSES : affecting the evidence given by the sense of touch, I consider only those really relating to the effects of con- tact, dealing separately with those re- lating to the effects of heat and cold. Aristotle long since pointed out how the sense of touch may be de- ceived when the organs of touch are employed in some unaccustomed manner. It was he who first men- tioned, if he did not invent, the ex- periment of rolling a pea between the tips of the first and second fingers, after the second finger has been crossed over the first. This experi- ment is instructive as showing how much of the significance of the teach- ings of our senses may be due to the effect of long-continued training. Every time we touch with the finger- tips an object of known shape, we are in reality teaching our fingers that Such and such impressions have such and such a meaning. When two fin- gers are crossed, the finger-tips re- ceive different impressions from those which they receive in their normal position, and we naturally misinter- pret the meaning of the impressions so received. Thus if I touch with my first and second fingers the sides of a space shaped thus w, the out- sides of the fingers come in contact with the curved surface, whereas the insides of the fingers feel such a sur- face as this, — ^ : so soon as the fingers are crossed these effects are reversed ; the outsides of the fingers are brought together by the crossing and touch a surface shaped thus^, telling us apparently that it is really a surface shaped thus ^ that we are touching. To test this apply the crossed fingers to a surface shaped /-v-s, so that the fingers touch the convex curves near their place of meeting; now we find that we no longer seem to be touching two curves, but one. It must be admitted, however, that this experiment is less striking than the other ; the informa- tion conveyed by the finger-tips in- stead of seeming definitely and de- cidedly incorrect, appears but vaguely erroneous. Let us try a few other experiments with crossed fingers. Take a pen- holder or pencil, and with first and second fingers crossed slide the fin- ger-tips along the pencil or holder. If the eyes are closed the fingers seem to tell us emphatically hai we are feeling two parallel rods. Yet u. the eyes are directed to the finger- tips the illusion disappears. This is not, however, because the eyec assure us that there is but one pen or pencil ; it is because the eyes show us that the fingers are crossed. To show that mere knowledge will not save us from the illusion, feel with the crossed fingers the tip of the nose. We know certainly that we have but a single nose-tip ; yet the absurd and illusory feeling that we have two noses is inv mediately produced. The illusion is strengthened if the crossed finger-tip*' are caused to slide along the ridge of the nose. Very curious illusions are produced if the crossed finger-tips are carried along either lip, or between the lips, or along the bone ridge below either eye or along the ridge above the eye, or round the ear, and so forth. But in my own case, the oddest illusion of all is obtained by crossing the forefinger behind the little finger, (both being bent some- what toward the palm, so that the second or third fingers are behind them) and then feeling with these crossed fingers the tip of the nose; for now, not only does the nose ap- pear double, but one ?iose appears to be longer than the other. One can easily understand why this is. Under ordinary conditions the first and little fingers cannot at the same moment feel two bodies which are equidistant from the observer, — or let us say from the palm. If, for instance, we place the forefinger tip on the end of a white note on the piano, the little finger tip can only rest on the end of another white note by bending the hand : we can, however, touch an end of a black note with the forefinger tip while the third finger tip touches the end of a black note, without bending the hand. The lesson taught, then, AND OTHER ESSAYS. 3 by constant experience (unnoticed through its very familiarity) is that two bodies so felt extend to different distances. But in the experiment with crossed forefinger and little fin- ger, the finger-tips touch at the same moment the same nose-tip, which appears double because touched by the outside edges of the fingers, and the two noses appear of unequal length because it seems as though the little finger touched one while the forefinger touches the other, each of them at the tip. Other singular effects may be pro- duced by crossing the fingers, varying the combinations. If the forefinger and second finger of the left hand be crossed as well as those of the right, and a small object be held between the crossed pair of each hand, the most incorrect ideas of the shape of the object are given. I have just tried the experiment, for instance, on a small box of pen-nibs, holding two opposite corners, one between the crossed finger-tips of the right hand, the other between those of the left hand ; it was impossible to realize that the object thus held had any reg- ularity of shape at all. Another experiment on the sense of touch depends on the circumstance that usually the outsides of the hands are so placed that if both touch two surfaces at the same time those sur- faces are not in the same direction. Of course the two hands can be placed side by side with their backs uppermost and a flat surface may so touch both ; but usually the palms are toward each other, and this is es- pecially the case when both hands are used in holding anything. Place the hands together, palm to palm, then cross the arms so that the hands are back to back ; if now a book is held between the backs of the hands its edge appears bent. The force of this illusion is different with different per- sons ; but let not those who are not affected by it rejoice as being less easily deceived than their fellows ; for, as Sir David Brewster remarks in speaking of an illusion affecting sight. it often happens that the most observ- ant are those most completely de- ceived by such illusions. There is another curious illusion of touch which appears to depend on the teaching which the hands and arms have had (unconsciously) in estimat- ing the dimensions of bodies held in the normal way, in front of the body. Suppose a book lying on a table be- fore you, the back of the book being toward the right. Take hold of it by the nearest right-hand corner (that is, holding it by the end of the back nearest to you) and pass it over the right shoulder so that the face which had been uppermost lies against the back of the right shoulder in a nearly vertical position. Now pass the left hand round behind you under the left shoulder-blade till you can grasp with it the edges of the leaves. You will now find that though you know from the feel of the edges that your left hand holds a side several inches from the back held by the right hand, that side of the book appears to be a con- tinuation of the back of the book, — so far as direction [is concerned. The explanation appears to be simply this : — When an object like a book is held in front of the chest, the right hand holding one side, the left hand reaches the opposite side without effort or stretching ; while with a slight amount of stretching the side held by the right hand can be reached ; now when the book is held behind the back in the way described above, an effort is required to reach with the left hand the side opposite that held by the right, hence the same effect is produced on the mind as when in the normal way of holding objects of the kind the left hand is stretched over to the right hand’s side of the object ; thus instead of the left hand touching the side opposite that held by the right, it appears to touch the same side. So much for illusions affecting touch. Or rather, these afford suffi- cient evidence that the sense of touch may be readily deceived. But in reality, scarcely a day passes without 4 ILLUSIONS OF THE SENSES: our noticing, if we are at all observ- ant, illusions “affecting this sense. If we observe the circumstances under which such illusions occur we gener- ally find that they arise when some organ of touch is used in a novel or unusual way. But in the. majority of cases arising in ordinary life the sense of touch acts in combination with either the sense of sight or the sense of hearing, and consequently the illu- sions arising are not such simple ex- amples of errors in the evidence afforded by the sense of touch as those considered above. The sense of heat is in like man- ner usually associated with the sense of sight, so that illusions affecting it are either corrected or modified by visual impressions. Yet there are cases where this sense is deceived when acting alone. For instance, there is the well known experiment in which after one hand has been placed for a time in water as hot as can be borne, and the other in ice- cold water, both hands are plunged simultaneously into tepid water. Im- mediately the hand which had been in very hot water recognizes a com- fortable sense of coolness, and as it were pronounces the water cold ; the other hand as quickly recognizes a comfortable sense of warmth and pronounces the self-same water hot. Here even sight will not correct the Illusion. We see as plainly as possi- ble that both hands are in the same basin, yet one hand seems to be in warm water, the other in cold. I find a singular effect produced if while the attention is strongly di- rected to the circumstance that both hands are in the same water, the hands are freely moved about in the water. For it seems then as though there were currents of hot and cold water in the same basin, moving so as to follow or rather to accompany the hands. Without making definite experi- ment in this way, we can easily in the ordinary experiences of life, rec- ognize the readiness of the heat sense to be deceived. Thus we come out of a warm room into the hall out- side and find the air there pleasantly cool. We then, perhaps, see a friend home through the cold night air and presently return to the same hall. But now, coming into it from the cold outer air, we find it pleasantly warm. Professor Le Conte remarks that “ during the Arctic voyages made by Parry, Franklin, Ross, Kane, Nares, and others, it was found that a zero temperature seemed quite mild after the thermometer had been twenty or thirty degrees below that point.” But, although in California temper- atures of twenty or thirty degrees below zero may not be common, an American has no occasion to leave the United States, or even the mid- dle states, to experience the illusion in question. I have repeatedly walked . along the streets of New York with the temperature a degree or two below zero, without wearing an overcoat or feeling the want of one, when such a temperature has followed a few days of much colder weather. And conversely, even as I write I am feeling unpleasantly cold at Columbia, South Carolina, with the temperature only just below zero (and the air still), simply be- cause I have been enjoying during the last few days in Charleston, S. C., a soft and balmy warmth resembling that of a June day in England. Again, in caverns like the Mam- moth Cave, Kentucky, or Kent’s Hole in Devonshire, there is in sum- mer always a sense of coldness and in winter always a sense of heat, yet in reality the thermometer shows that, as might be expected, the air is somewhat warmer within such caves in summer than it is in winter. Here, then the illusion is not only incor- rect but the very contrary of the truth ; the air seems colder when it is really warmer and warmer when it is really colder. Because the range of temperature is much less within the cave than in the open air, we are de- ceived into ike idea that the tempera- ture really ranges the reverse way from that in which it actually varies. AND OTHER ESSAYS. D A muic subtle illusion relating to heat is that arising from difference in the conducting power of various substances with which the skin is brought into contact. Thus if we plunge into water of the' very same temperature, when tested by the ther- mometer, as the surrounding air, both being really cooler than the body, the water seems cold, because being a better conductor than air, it immediately begins to carry off more of the body’s warmth. On the con- trary, the self-same substance — water — not only feels hot but is unbear- ably hot when at a temperature far below that of the surrounding air in a Turkish bath. It is to be noticed that in this case the sense of heat while in one respect leading to an erroneous idea, in an- other and a much more important point gives correct information. If one were to trust the teachings of the thermometer, and infer that one might as well remain in water as in air seeing that the water and the air are of the same temperature, one would make a serious mistake, and suffer a good deal of harm through the rapid abstraction of warmth from the body. The heat sense, by telling us wrongly that the water is colder than the air, conveys at least the much more important information that we are losing heat while in the water, — and therefore saves us from the danger of getting unduly chilled, as we might if we trusted to the ther- mometer alone. In the reverse case, the sense of heat acts even more di- rectly and emphatically for our bene- fit. I remember a case in point which occurred at the Hummums. Some one who had heard that the tem- perature of water in the hot rooms is always much lower than the tem- perature of the air, but had not considered the matter with actual reference to the requirements of the human body, supposed that he would gain decidedly in comfort if instead of sitting on the non-conducting felt or flannel of the seats, he were to substitute a roll of towels well soaked in water. He found as a matter of fact that the arrangement thus sug- gested by the thermometer was very far from being welcomed by the nerves of touch, — whose repugnance to the arrangement was indeed most emphatic. It is hardly necessary to say, per- haps, that the whole question of clothing, especially for young people, depends on the relation between the conducting powers of various sub- stances used for clothing. In this matter the sense of heat gives more trustworthy information than the thermometer, clothes which seem to be of the same temperature if tested by the thermometer affording very different degrees of protection against the loss or the too rapid ac- cession of heat. In passing, I may note here an important consideration as to the clothing proper for children. In their case as in the case of grown folk the sense of heat gives the best information as to what is really de- sirable in the way of clothing. But grown people are apt to forget the experiences of their childhood, and to decide what is best for children from their own ideas as to what ought to be best. A child complains of cold or of heat sooner than a grown per- son ; but much less attention is paid to the complaints of children on such matters than to our own slightest sug- gestions of personal discomfort. And children are much less carefully guarded against heat and cold than grown persons guard themselves. The idea seems to be that children can stand any changes of tempera- ture ; though, oddly enough, children’s own idea (which is really not very far from the truth) that they can stand anything in the way of rich and indi- gestible eating, is not much considered by older persons. Now, when a child shows by its words or actions that it suffers sooner from changes of tem- perature than grown people do, it in reality expresses its sense of an im- portant truth. A child cools and 6 ILLUSIONS OF THE SENSES : warms more quick-ly than a man ; for precisely the same reason that a small cinder cools more quickly than a large one, or that a small fire burns out more quickly than a large furnace. Compare the case of a child three feet high with that of a man six feet high. Neglecting slight differences of build, the man is about eight times as large as the child, or contains eight times as much matter. But the sur- face of the man is not eight times as large as the surface of the child ; it is only four times as large. Thus sup- posing the man and the child to come out of a warm room into the cold outer air, being both at the same tem- perature, the man has eight times as much heat to part with as the child has ; but he only parts with four times as much heat, moment by moment, if he and the child are similarly clothed. Thus the child’s loss of heat, moment by moment, though only one-fourth of the man’s loss of heat, bears twice as great a ratio to the child’s total supply of heat. The child will cool as much in one minute as the man cools in two minutes, or in half-an-hour as the man cools in an hour. If the weather out- side is so cold that the man would suffer serious injury to his health after an hour’s exposure to it, the child will suffer at least an equal injury in half- an-hour. In reality, of course, the child will suffer a greater injury ; be- cause apart from his more rapid loss of heat, the child’s flesh is more ten- der and necessarily suffers more from a given loss of temperature. Similar remarks apply to increase of heat, which may be just as mischievous as access of cold. Yet we are too apt to clothe children with total disregard to the circumstances that they require to be protected much more carefully than their elders against rapid changes of temperature. Apart from all ques- tions of propriety, a man would not care even on a fairly warm spring day to go about with his arms and legs bare for any length of time ; for he would feel uncomfortably cool : chil- dren suffer twice as much on such a day from undue exposure to the air ; yet many foolish folk think nothing of exposing the delicate limbs of children to the cold of winter without protec- tion. They imagine that the numb- ness and insensibility which really indicate the mischievous effects of the cold, and may permanently affect the the child’s constitution, are signs of hardening ; and because only the hardier survive this cruel treatment they imagine that those hardy sur- vivors owe the strength which enabled them to survive, to the harsh exposures by which that strength was danger- ously taxed and perhaps in large measure sapped. It is, however, the sense of sight which has most thoroughly deceived the student of science, almost justify- ing Professor Le Conte’s statement that no evidence is more misleading and fallacious than the evidence of the senses. So far from seeing being believing, one recognizes that often we see an object wrongly tinted, wrongly illuminated, wrongly shaped, besides that fault of wrong apparent size which we might expect to recog- nize in the case of a sense like sight (which gives no direct evidence as to distance). Taking this last defect of sight-evi- dence first, we note that the eye-sight cannot really be said to delude us when it seems to tell us that — for ex- ample — the moon is as large as the sun. All that sight really tells us is that the sun and the moon occupy fields of view of the same apparent size. This, of course, is correct in- formation as far as it goes, and the sense of sight cannot go further. But the sense of sight conveys false ideas to the mind, sometimes even about ap- parent size. Perhaps the most remarkable case of the kind — at any rate the most fa- miliar — is the apparent increase of the sun and moon in size as they approach the horizon. Singularly enough, Professor Le Conte does not regard this as an optical illusion ; “ the visual angle being in both cases precisely the same, the size of the im- age on the retina must have been the AND OTHER ESSAYS. 7 same.” But one might with equal reason say that none of the illusions relating to touch or heat are really il- lusions, seeing that the actual effects produced on the nerves of touch cor- respond with the actual shapes or temperatures of the objects felt. In every case of sense illusion the nerves give correct information, it is the in- terpretation of the information which is incorrect. The apparent largeness of the moon near the horizon is of course a real il- lusion. It is often elaborately ex- plained as due to the magnifying power of the layers of air through which the moon is viewed. In the “ Wide Wide World ” the overwhelm- ingly wise John Marchmont explains the matter thus to Ellen Montgomery (I hope my recollection of the names is trustworthy, but the book came out a long while ago, and I have not seen it since its first appearance). But the moon is not magnified at all in that sense. She does not occupy a larger space in the visual field. Nay she looks rather smaller when near the horizon, being then nearly 4,000 miles nearer to us than when overhead. It is easy to show this ; and in passing I cannot too earnestly recommend those who wish to form correct ideas about the apparent sizes, shapes, posi- tions, and movements of the heavenly bodies, to test such matters in simple ways such as I am about to suggest in the moon’s case. Cut out in card a circle exactly half an inch in diame- ter, leaving a projecting piece of card outside some part of the rim. Then take a straight rod about 54 inches long, and with a tack through the pro- jecting piece fasten the disc at one end of the rod, so that the whole disc is visible from the other end. Now it will be found that if the rod be di- rected toward the moon, the disc of card at the end furthest from the eye, will just hide the moon from an eye placed at the nearest end. Whether the moon is high up in the sky or close to the horizon the same thing hap- pens. The moon looks just as large high up as she does low down, on any given night. Of course, as the moon’s path round the earth is not quite cir- cular there is a change in the moon’s apparent size in the course of each lunar month, — a change which the method of measurement just described will serve very well — rough though it is — to indicate. Just as the sun va- ries in apparent diameter as the year progresses, his diameter on January 1, bearing to his diameter on July 1 the ratio 31 to 30, so the moon varies as the month progresses, and in greater degree. But look at the moon from one end of the rod when she is rising and you will find the card disc at the other end cover her either exactly or very nearly, and when she is at her highest on the same night you will find her as exactly or as nearly cov- ered by the card disc the rod being directed in the same way toward her, and the disc viewed by an eye placed at the other end of the rod. Here then is an optical illusion by which the idea is conveyed that the moon is larger when low down than she is when high above the horizon, though in reality occupying as large (nay, even a slightly larger) portion of the visual field. It is the same with the sun, and the same also with any one of the familiar star groups which pass from close by the horizon to a great distance above it. How is this deception to be explained ? The increase of the moon’s size near the horizon has been attributed to the circumstance that when she is low down we can compare her appar- ent size with that of known objects near the horizon, and seeing that she looks larger than many objects which are known to be really large, as trees, houses, and so forth, we can judge that she is larger than we had (uncon- sciously) supposed her to be when high up. But I cannot see that there is any force in this explanation. It is true that if the moon when low down is looked at through a tube of any sort, hiding surrounding objects, she no longer appears so large. But this does not prove that the surrounding objects make her look larger, other 8 ILLUSIONS OF THE SENSES: relations besides those depending on the appearance of surrounding ob- jects are concealed by the tube ; and amongst them that which is, I take it, the true explanation of the moon’s apparent increase of size. The fact is that the increase in the apparent size of the moon and other celestial objects as they draw nearer to the horizon is connected with a much wider illusion affecting the ap- parent dome-shape of the sky over our heads. Of course when we look at a cloud- laden sky we perceive at once that our range of view is not limited by the interior of a hemispherical surface. The region above our heads seems shaped like the interior of a very much flattened dome, the horizon being much farther away than the sky di- rectly overhead. When the sky is clear the dome above us seems more arched, but it never appears like a true hemisphere. Probably to ordi- nary eye-sight the star-strewn sky on a clear night appears shaped as though the part directly overhead were at only about one-quarter the distance of the part near the horizon. But of course the range of the moon’s path around any observer on earth is such that her distance varies very slightly, as if in fact she. always moved on the inner surface of a sphere having the observer at its center. To one then who entertains unconsciously the er- roneous notion that the sky is arched over the earth, in such sort that the region overhead lies at about a fourth the distance of the horizon, the expec- tation unconsciously arises that when the moon is close to the horizon she will present a smaller disc than when she is high up in the sky. As a mat- ter of fact, she looks about as large (not quite, but very nearly), that is, she subtends the same visual angle ; but the effect of her looking so much larger than had been unconsciously ex- pected, is to suggest that she is really larger than when high above the hori- zon. We apply to her the same un- conscious reasoning by which we rec- ognize that a tree on the horizon which subtends the same apparent angle as a tree close by is much the larger of the two. Having in reality no means of estimating the real size of the moon, we make its apparent po- sition guide us to an idea of its size, and as it seems — being near the hori- zon — much . farther away than when high, yet looks no smaller, we judge it to be really larger. I had a singular example recently of the effect of position in forcing an illusory idea on the mind, even when the truth was well and even familiarly known. I was in the streets of Charleston (South Carolina) engaged in conversation, but my eyes directed toward the upper ridge of a project- ing balcony. While I talked, I saw what looked like a bird’s head rising just beyond the ridge, and in a moment or two there was the creat- ure, a tiny but very oddly shaped bird apparently fluttering above the balcony. It looked no larger than a humming-bird. Now I knew at once that I was not looking at a bird, be- cause I could see that the object had a pendent waving tail such as no bird ever had. I knew as well that it was not a small bird close by, but a Chi- nese kite at a considerable distance, as I knew that it was day; yet be- cause my mind had started with the wrong idea that the object was just above the balcony, I could not for several seconds shake off the absurd impression that there was a miniature bird-kite fluttering above a straight stone ridge where assuredly was no string attached to it. I take it that the deception by which, against my own knowledge, I was for awhile made to imagine the kite much smaller than it really was, because it seemed much nearer than such an object is usually seen, was precisely akin to the illusion by which, against our own knowledge we are led to imagine the moon much enlarged near the horizon because it there seems much farther away than as seen high up toward the zenith. The illusion as to the shape of the heavens around us and the sky above AND OTHER ESSAYS. us (not the same thing be it noticed) is one which deceives us all the time, — at least I have never met with any- one who has been able to correct either form of illusion. We conceive the heavenly bodies overhead to be nearer to us than those near the hori- zon, the heavenly concave being pre- sented as somewhat flattened over- head : and on the other hand a cloud- covered sky appears arched overhead instead of having a flat horizontal sur- face. Do what we will we cannot force the mind to feel either that the stars overhead are no nearer than those by the horizon, or that the clouds near the horizon are as much farther away than those overhead, as they really are. The clouds low down seem somewhat farther away than those above our heads, — perhaps four or five times farther : but in reality they are usually twenty or thirty t’imes farther from us. But the mind refuses to present to us the much greater dis- tance of those low-lying clouds. It may be said, indeed, that the mind is unable to conceive a spherical sur- face, either convex or concave, beyond a certain size, which differs probably in the case of each person, differs cer- tainly as life advances, and is far short of the dimensions of any one of the celestial globes, except possibly the moons of Mars. It maybe that if living in Fear or Terror (as the attend- ants on Mars have been called) we might recognize the rotundity of the surface of our home, seeing that prob- ably neither of these moons has a diameter of more than twenty miles. But it is certain that no one can ap- preciate the rotundity of our earth, in such sort that not merely the circum- stance that the globe is rotund is recognized, but the dimensions of the globe of which the region we see at any moment is a part. The best proof of this is found in the fact that the earth’s surface appears concave so soon as we see any very large extent of it. As seen from a balloon, for in- stance, the earth seems like a gigantic basin, the mind not being able to take in the real truth that the earth is too large for the horizon to dip recogniza- bly even when the eye is two or three miles above the earth’s surface. If one could pass away from the earth to distances so great that she would be visible as a globe, we should still be unable to form any idea of her size, — just as now the sun, moon, planets, and stars tell the eye nothing of their real dimensions. A curious question here suggests itself : — Supposing one could pass away from the earth’s surface steadily till she appeared like a globe, what would be the changes her aspect would undergo ? She would certainly appear concave until a great height had been attained ; and as certainly she would eventually appear a globe as the sun and moon do : but in what way, I wonder, would the apparently concave surface pass to a manifestly convex surface ? Would this happen gradu- ally, or would the conviction suddenly force itself on the mind that the sur- face which had appeared concave was really convex? There is a familiar illusion which illustrates such a change as this, and seems to suggest that the change of appearance would be sud- den. If you look through a lens, in- verting the object seen, at a convex surface, it appears to be concave (a coin under the same conditions, ap- pears to have all the parts which "are really in relief depressed) because the mind recognizes the evidence given by the shadows without being con- scious that this evidence has been in- verted by the action of the lens. Now if, while the convex surface thus ap- pears concave you introduce into the field of view some object which shows which way the shadows really fall — as an upright pin, or the like — you find the seeming concavity at once changed to convexity, the mind being unable to note how the change takes place, so rapid is it. Possibly this would be the way in which the seem- ing concavity of the earth would change to convexity, as we passed away to the distances at which the earth would appear like a celestial orb. 10 ILLUSIONS OF THE SENSES: Illusions affecting our ideas about the apparent brightness of objects are even more deceptive than those affect- ing form. The French astronomer Chacornac wrote an article once in explanation of the superior brightness of the discs of Jupiter and Saturn near the edge. The explanation was in- genious, and would have perhaps thrown light on the nature and con- dition of the giant planets, if it had only chanced that the superior bright- ness which he explained had a real existence. As a matter of fact, how- ever, so far are the parts of Jupiter and Saturn near the edge of their discs from being brighter than the parts near the middle that the precise reverse is the case, and in quite a marked degree. I was first led to observe this by theoretical considera- tions, which seemed to suggest that the light from the parts of Jupiter near the edge ought to be very much less than the light from the middle of the planet’s disc. It so chanced that just as I had satisfactorily reasoned this out, I came across Chacornac’s article explaining why the edge is so much and so obviously brighter than the middle. This led me to inquire whether the case really was as he supposed or not. Now, to those who have paid attention to the phenomena of Jupiter’s satellites, many circum- stances are knowrn which show that the edge of Jupiter’s disc must be darker than the middle. For exam- ple, a satellite looks light when near the edge, dark when on the middle of the disc ; or else (which proves the same thing) a satellite is scarcely vis- ible near the edge, being so nearly of the same lustre as the planet, but as it passes on to the brighter central parts of the disc it becomes a dark spot, sometimes even looking as dark as its own shadow close alongside. All this in reality proves that the edge is darker than the middle of the disc ; yet it looks decidedly brighter. I suggested, therefore, to a friend who was making experiments on the lumi- nosity of various celestial bodies, that he should test this matter by deter- mining whether the parts of Jupiter’s disc near the edge or the parts near the middle remained longest visible when the light of the planet was grad- ually extinguished by means of a neu- tral-tinted darkening glass (graduated from almost complete transparency at one hand to almost complete opacity at the other). The result was deci- sive, and exactly contrary to the evi- dence of the eyes. The parts which to the eye seemed so obviously the brightest were the first to yield to the absorption of the light, the parts which looked least bright remained visible longest. Of course, the illusion is easily explained. By contrast with the black background of the sky the parts near the edge of Jupiter and Saturn look brighter than they really are. A noteworthy illusion was passingly indicated in what I have just de- scribed. I have said that a satellite sometimes looks as dark as its shadow close alongside. Now the shadows of the satellites look black ; but the satellite itself cannot be black. We see then that the appearance of black- ness does not necessarily imply real blackness. So the spots on the sun look black near the middle of the umbra ; yet they cannot be really black there ; and indeed when examined so that the effect of contrast is avoided they are found to emit a considerable amount of light. Another case of illusion may be noticed in total eclipses of the sun. Here the body of the moon looks black ; yet in reality it is lit up at least twelve times as brightly as a landscape under full moonlight, for the earth is at the time of solar eclipse shining full upon the half of the moon turned earthwards, and her disc is 13^ times as large as the moon’s appears to us. To my mind, one of ttfe best proofs of the brightness of the solar corona, is found in the seeming blackness of the moon’s disc during total solar eclipse. But the seeming whiteness of the moon’s disc when she is full is quite as much an illusion as its seeming blackness when she is between the AND OTHER ESSAYS. 11 sun and us. For the moon is not really white. She is much more nearly black. Regarding ioo as rep- resenting perfect whiteness, the aver- age tint of the moon's surface would be represented by only 17. Probably the darker portions, which, when she is full look only slightly less white than the rest, are as dark as our por- phyries and syenites. Another remarkable illusion affect- ing brightness is that which has de- ceived several students of the moon in the case of the floor of the lunar crater, Plato. This broad expanse •seems to grow darker as the sun rises higher above its level ; but this is a pure illusion, due to the gradual dim- inution of the black shadows of the surrounding mountains. By contrast with these shadows the floor looks lighter than it really is ; as they dimin- ish it seems to grow darker ; when they disappear altogether it looks darkest ; and as they gradually grow larger in the afternoon and evening of the long lunar day there, the floor seems to get light again. As a matter of fact the floor gets brighter as the sun rises higher above its level, and darkens again as the sun gradually nears the horizon of Plato. The illusions affecting motion are too remarkable and too numerous to be dealt with properly in the small space remaining to me here. I may, perhaps, consider them hereafter in a separate short essay. ANIMALS OF THE PRESENT AND THE PAST. Mr. Grant Allen (for to his facile pen the article on “ Big Animals,” in a recent number of the Cornhill Mag- azine may safely be attributed), has done good service in showing how unfounded are two very prevalent ideas respecting the past of this earth on which we live — viz., first, the idea that the various races of animals which appear in the geologic record all ex- isted at some remote time (“ in those days,” meaning some imaginary epoch specially belonging to geological science) ; and secondly, the idea that in past ages the animals existing on the earth were very much larger than those now known. As regards the first idea, relating to geological time, the Pleistocene age is really as yesterday in the past history of our earth, and the Pliocene as the day before yesterday. The mammoth in the northern hemisphere, and the moa in the southern, are creatures of yesterday, while the mastodon, on the same time scale, can be set no further back than the last generation or so. On the other hand, the “ monstrous ” marine saurians of the Jurassic era are of remote antiquity. Mr. Allen expresses the relation, in point of time, neatly, when he says that “ to compare the relative lapses of time with human chronology, the mastodon stands to our own fauna as Beau Brummel stands to the modern masher, while the saurians stand to it as the Egyptian and Assyrian warriors stand to Lord Wolseley and the fol- lowers of the Mahdi.” In fact, the mind, as regards its power of dealing with time-intervals, is lost in the pres- ence of the vastness of the era to which our own period belongs as com- pared with the minute span over which history extends its survey — is lost, yet once more, in comparing even with the vastness of the glacial period the seemingly immeasurable duration of the Pliocene and its still longer predecessor the Miocene, and, endeavoring to look beyond these in- to still remoter depths of past time, is simply appalled. The Eocene was so long-lasting, that the sequent eras, which with it make up the Tertiary period, seem by comparison as seconds compared with hours. But the whole duration of the Tertiary period is in- significant compared with the incon- ceivable length of the Secondary pe- riod, while the Secondary period, in turn, is short compared with the Pri- mary period, and even this tells us only of the close of a yet more tre- mendous time-interval, during which U, OF ILL US. 12 ILLUSIONS OF THE SENSES : no trace was left of the earth’s prog- ress to the world form, any more than the sea leaves any. record of the prog- ress of the storms which sweep over its vast surface. Truly it is amazing to consider now, when these vast periods of time have taken their place among the recognized and assured teachings of the great earth volume, that but half a century or so ago a struggle was still maintained to reduce our estimate of the earth’s past existence to a few thousands of years, while multitudes of well-meaning persons imagined that an eternity of future happiness or misery depended on each man’s re- jection or acceptance of the doc- trine which God’s work, the earth, assuredly teaches. Yet, strangely enough, the school of those who maintained that hopeless struggle is not ashamed even now to denounce the followers of the scientific school for accepting the obvious meaning of these new pages of that great vol- ume which have since been turned over. With regard to the dimensions of the modern inhabitants of the earth, we must remember that to every era of the earth’s history a special kind of development has been specially appropriate. It is certain that the great land monsters of the Jurassic age could not exist now. For while their numbers must have always been limited, even when surrounding con- ditions favored their existence, the powers of the human race at the present time would be fatal to the existence of these unwieldy monsters. The monstrous eft, which of old was lord and master of earth, might main- tain, at least for awhile, the position of lord and monarch still, were it not for man. But with man in the arena against the Atlantosaurus, one or other would have to give way, and it would not be man. The mammals of the Pliocene age were not so much greater than their modern represent- atives that we need consider them specially. And assuredly when we turn to the sea-monsters of our own time we need not fear comparison with even the mightiest monsters of past geological ages. The Rorqual attains sometimes to a length of fully one hundred feet, the razor-back whale sometimes measures seventy feet, and there are other cetaceans not much inferior in size. As to the dimensions of sharks, some doubt appears to exist. Considering the nature of the creature, and that men have never found it desirable to hunt for sharks as they have for w r hales (possibly if they had they would have made but unsatisfactory progress in the art of shark-hunting), it would be absurd to suppose that we have be- come acquainted even with the larg- est existing varieties, far less wfith the largest individual specimens. To give an idea of the state of things in regard to sharks, I may record an experience of my own. In the voy- age from Auckland, N. Z., to Hono- lulu, the City of Sydney was tempo- rarily disabled by the breaking of a crank-pin. Up to the day when this accident occurred, not one among the crew or passengers had seen a single shark of any kind, though the passengers certainly passed a good half of their time looking at the waters around them. But scarcely had we been at rest a quarter of an hour before the sea all around our disabled ship was literally swarming with sharks. When I learn, there- fore, that the naturalists of the Chal- lenger expedition have dredged up in numbers from the ooze of the Pacific shark teeth five inches long by four wide, which would indicate that the sharks to which these teeth belonged were a hundred feet long, I feel no doubt that sharks of these dimen- sions are still in existence. Dr. Gunter, of the British Museum, writes, it is true, that “ as we have no record of living individuals of that bulk, the gigantic species to which the teeth belonged must probably have become extinct within a com- paratively recent period.” And Mr. Grant Allen speaks of him as a very cautious naturalist for thus avoid- AND OTHER ESSAYS. 13 ing the natural conclusion that the species is not extinct at all. But to my mind it savors of much greater daring to imagine the extinction than the existence of these gigantic carchar- odons. We know of nothing which could probably have led to the ex- tinction of monsters such as these, which would have all their own way among the denizens of the great deep. Man has not sought their destruction as he has sought the destruction of species of whales which nevertheless still exist; they cannot have been attacked and destroyed by other species of fish, or even conceivably deprived of the means of living by more active and predaceous creatures. That they should die out, then, seems altogether unlikely ; whereas it is altogether natural that they should remain unknown amid the depths of the mighty ocean, for they would keep to the great deep, avoiding even an approach to shallows, nor would they be apt to show where the smaller and more numerous orders of sharks are seen. Albeit I may remark that Mr. Allen seems to me mistaken in as- suming that the monstrous sharks to whom these teeth belonged were as large as any sea creatures of re- mote geological eras. I have in my possession shark’s teeth collected in the neighborhood of Charleston, S. C., which are 5)4 in. long by 4)4 in. broad, and in the Museum of Charles- ton they have shark’s teeth much larger even than that. The largest calamaries of the pres- ent time are certainly larger than any of those whose remains exist as fos- sils. A cuttle thrown up on the shore of Newfoundland was 80 ft. long. On the whole, it may be doubted whether at any time in the past his- tory of the earth the average size of the ten largest creatures by sea and land exceeded the average size of the ten largest species existing at the present day . — Newcastle Weekly Chronicle. LIFE IN OTHER WORLDS. So far back as 1869, I had begun to regard doubtfully the theory that all the planets are the abode of life. The careful study of the planets Jupi- ter and Saturn had shown that any such theory regarding these planets is altogether untenable. The great dif- ference between them and the mem- bers of the smaller planetary family of which our earth is the chief, suggest- ed that in truth the major planets be- long to another order of orbs alto- gether, and that we have as much or as little reason for comparing them to the sun as for comparing them to the earth on which we live. Never- theless, in the case of Venus and Mars, the features of resemblance to our earth predominate over those of dissimilarity ; and it was natural that, while rejecting the theory of life in Jupiter or Saturn as opposed to all the available evidence, I should still consider the theory of life in Mars or Venus as at least plausible. Ideas on such subjects are not less tenacious than theories on matters more strictly scientific. Not only so, but the bearing of newly-recognized facts on long-entertained theories is not at once recognized even by those most careful to square their opin- ions according to the evidence they are acquainted with. Again and again it has happened that students of science (in which term I include the leaders of scientific opinions) have been found recording and explaining in one chapter some newly-recognized fact, while in another chapter they have described with approval some old theory, in total forgetfulness of the fact that with the new discovery the old theory has become altogether un- tenable. Sometimes the incongruity is not recognized until it has been pointed out by others. Sometimes so thoroughly do our prepossessions become “ bone of our bone and flesh of our flesh ’’that even the clearest reasoning does not prevent the stu- dent of science from combining the 14 ILLUSIONS OF THE SENSES: acceptance of a newly-discovered fact 1 with continued belief in a theory which that fact entirely disproves. Let the matter be explained as it may, it was only gradually that both the Brewsterian and Whewellite theories of life in other worlds gave place in my mind to a theory in one sense intermediate to them, in another sense opposed to both, which seems to ac- cord better than either with what we know about our own earth, about the other members of the solar system, and about other suns which people space. What I now propose to do is to present this theory as specially il- lustrated by the two planets which now adorn our skies at night, and by the ruddy but at present invisible Mars. But it may be asked at the outset, whether the question of life in other worlds is worthy of the attention thus directed to it. Seeing that we have not and can never have positive knowledge on the subject, is it to be regarded as, in the scientific sense, worthy of discussion at all ? Can the astronomer or the geologist, the phys- icist or the biologist, know more on this subject than those who have no special knowledge of astronomy, or geology, or physics, or biology ? The astronomer can say how large such and such a planet is, its average density, the length of its day and its year, the light-reflecting qualities of its surface, even (with the physicists’ aid) the nature of the atmosphere sur- rounding it, and so on ; the geologists can tell much about the past history of our own earth, whence we may in- fer the variations of condition which other earths in the universe probably undergo ; the physicist, besides aid- ing the astronomer in his inquiries into the condition of other orbs, can determine somewhat respecting the physical requirements of living creat- ures ; and the biologist can show how the races inhabiting our earth have gradually become modified in accord- ance with the varying conditions sur- rounding them, how certain ill-adapt- ed races have died out while well- 1 adapted races have thriven and multi- plied, and how matters have so pro- ceeded that during the whole time since life began upon our earth there has been no danger of the disappear- ance of any of the leading orders of living creatures. But no astronomer, or geologist, or physicist, or biologist, can tell us anything certain about life in other worlds. If a man pos- sessed the fullest knowledge of all the leading branches of scientific re- search, he would remain perfectly ignorant of the actual state of affairs in the planets even of our own system. His ideas about other worlds must still be speculative ; and the most igno- rant can speculate on such matters as freely as the most learned. Indeed, the ignorant can speculate a great deal more freely. And it is here, pre- cisely, that knowledge has the ad- vantage. The student of science feels that in such matters he must be guided by the analogies which have been already brought to his knowl- edge. If he rejects the Brewsterian or the Whewellite theory, it is not be- cause either theory is a mere specu- lation for which he feels free to sub- stitute a speculation of his own ; but because, on a careful consideration of the facts, he finds that the analo- gies on which both theories were based were either insufficient, or were not correctly dealt with, and that other analogies, or these when rightly viewed, point to a different conclu- sion as more probable. Nor need we be concerned by the consideration that there can be no scientific value in any conclusion to which we may be led on the subject of life in other worlds, even though our method of reasoning be so far scien- tific that the argument from analogy is correctiy dealt with. If we look closely into the matter, we shall find that as respects the great purposes for which science is studied, it is as instructive to think over the question of life in other worlds as to reason about matters which are commonly regarded as purely scientific. It is scientific to infer from observations. AND OTHER ESSAYS. 15 of a planet that it has such and such a diameter, or such and such a mass ; and thence to infer that its surface contains so many millions of square miles, its volumes so many millions of cubic miles, its mass so many billions or trillions of tons ; yet these facts are not impressive in themselves. It is only when we consider them in connection with what we know about our own earth that they acquire mean- ing, or, at least, that they have any real interest for us. For then alone do we recognize their bearing on the great problem which underlies all science, — the question of the mean- ing of the wonderful machinery at work around us ; machinery of which we are ourselves a portion.* In suggesting views respecting Jupi- ter and Mars unlike those which have been commonly received with favor, it is not by a»y means my purpose, as the reader might anticipate, to de- part from the usual course, of judging the unknown by the known. Al- though that course is fraught with difficulties, and has often led the student of science astray, it is in such inquiries as the present the proper, one may almost say the only, course. The exception I take to the ordinary views is not based on the fact that too much reliance has been placed on the argument from analogy, but that the argument has been incorrectly * It has often seemed to us that a descrip- tion, by the close observer Dickens, of the fancies of a brain distempered by fever, cor- responds with feelings which the student of science is apt to experience as the sense of the awful mystery of the universe impresses itself on his soul : — “ The time seemed inter- minable. I compounded impossible exist- ences with my own identity. ... I was as a steel beam of a vast engine, clashing and whirling over a gulf, and yet I implored in my own person to have the engine stopped, and my part in it hammered off.” Of all the wonders that the student of science deals with, of all the mysteries that perplex him, is there aught more wonderful, more perplexing than the thought that he, a part of the mighty machinery of the universe, should anxiously inquire into its nature and motions, should seek to interpret the design of its Maker, and should be concerned as to his own share in the working of the mysterious mechanism ? employed. A just use of the argu- ment leads to conclusions very differ- ent from those commonly accepted, but not less different from that theory of the universe to which Whewell seems to have felt himself driven by his recognition of the illogical nature of the ordinary theory respecting the plurality of worlds. Let us consider what the argument from analogy really teaches us in this case. The just use of the argument from analogy requires that we should form our opinion respecting the other plan- ets, chiefly by considering the lessons taught us by our own earth, the only planet we are acquainted with. In- deed, it has been thus that the belief in many inhabited worlds has been supported ; so that if we employ the evidence given by our own earth, we cannot be said to adopt a novel method of reasoning, though we may be led to novel conclusions. The fact that the earth is inhabited, affords, of course, an argument in favor of the theory that the other planets are also inhabited. In other words a certain degree of probability is given to this theory. But we must look somewhat more closely into the matter to ascertain what the probabil- ity may amount to. For there are all orders of probability, from certainty down to a degree of probability so low that it approaches closely to that extremest form of improbability, which we call impossibility. It is well at once to take this logical basis ; for there are few mistakes more mischiev- ous than the supposition that a theory supported by certain evidence derives from that evidence a probability equal to that of the evidence itself. It is absolutely certain that the one planet we know is inhabited ; but it by no means follows certainly that planets like the earth support life, still less that planets unlike the earth do so, and least of all that every planet is now the abode of life. A higher degree of probability in favor of the theory that there are many inhabited worlds arises from a 16 ILLUSIONS OF THE SENSES: consideration of the manner in which life exists on the earth. If one could judge of a purpose (according to our way of thinking) in all that is going on around us, our earth might teach us to regard the support of life as Nature’s great purpose. Earth, water, and air alike teem with life. No peculiarities of life seem able to banish life. As I have said else- where, “ in the bitter cold within the Arctic regions, with their strange al- ternations of long summer days and long winter nights, their frozen seas, perennial ice, and scanty vegetation, life flourishes in a hundred different forms. On the other hand, the torrid zone, with its blazing heat, its long- continued droughts, its strange ab- sence of true seasonal changes, and its trying alternations of oppressive calms and fiercely-raging hurricanes, nourishes even more numerous and varied forms of life than the great temperate zones. Around mountain summits as in the depths of the most secluded valleys, in mid-ocean as in the arid desert, in the air as beneath the surface of the earth, we find a myriad forms of life.” Nor is the scene changed when, with the mind’s eye, we contemplate the earth during past ages of her history, even to the most remote stage of her existence as a planet fit to be the abode of life. Whenever there was life at all, there was abundant life. For, though no traces remain of a million forms of life which co-existed with the few forms recognized as belonging to this or that geologic era, yet we can infer from the forms of which traces re- main that others must have been present which have left no trace of their existence. The skeletons of mighty carnivora assure us that mul- titudes of creatures existed on which those monsters fed. The great sea- creatures whose remains have been found, attest the existence of many races of small fish. The mighty Pterodactyl did not range through desert aerial regions, for he could exist only where many orders of aerial creatures also existed. Of minute creatures inhabiting the water we have records in the strata formed as generation after generation sank to the sea bottom after death, whereas the correspondingly minute inhabitants of the land and of the air have left no trace of their existence ; yet we can feel no reasonable doubt that in every geologic age, forms of minute life were as rich in air and on the land as in the sea, or as they now are in all three. Of insect life all but a few traces have passed away, though occasionally, by some rare accident, even so delicate a structure as a butterfly’s wing has left its rec- ord, not only attesting the existence of hosts of insects, but showing that delicate flowers, with all the charms of sweet perfume and variegated color, existed in those times as in ours. It is no mere speculation, then, but the direct and unquestionable teaching of geology, that throughout the whole time represented by the fossiliferous rocks, life of all kinds was most abundant on our earth. And while we thus recognize throughout our earth’s history as a planet, Nature’s apparent purpose of providing infinitely varied forms of life at all times and under the most varied conditions, we also perceive that Nature possesses a power of modifying the different types in ac- cordance with the varying conditions under which they subsist. Without entering here into the vexed question of the actual extent to which the principle of selection operates, we must admit that it does operate largely, and that it must necessarily cause gradual change of every type of living creature toward the most suit- able form. This particular operation of Nature must certainly be regarded as an apparent carrying out of the purpose attributed to her, — by our manner of speaking when we say that Nature’s one great object is the sup- port of life. If types were unchange- able, life would come to an end upon a globe whose condition is not only not unchangeable, but changes largely in the course of long periods of time. AND OTHER ESSAYS. 17 But types of life . change, or can ! change when required, at least as j quickly as the surrounding conditions — save in the case of certain catastro- phes, which, however, never affect any considerable proportion of the earth’s surface. Nor is it easy to assign any limits , to this power of adaptation, though we can scarcely doubt that limits vxist. | The earth may so change in the course of hundreds of thousands of years to come that none of the chief forms of life, animal or vegetable, at present existing, could live even for a single year under the changed con- ditions of those distant times, while yet the descendants of creatures now living (including man) may be as well fitted to the circumstances around them as the most favored races of our own time. Still there / must be a limit beyond which the I change of the earth’s condition, / whether through the cooling of her \ own globe or the diminution of the sun’s heat, will be such that no con- ceivable modification of the types of life now existing could render life possible. It must net be forgotten that Nature’s power of adaptation is known to be finite in many cases, and therefore must be presumed to be finite in all cases. The very process of selection by which adaptation is se- cured implies the continual failure of preceding adaptations. The struggle for life involves the repeated victory of death. The individuals which perish in the struggle (that is, which perish untimely) far outnumber those which survive. And what is true of individuals is true of types. Nature is as wasteful of types as she is of life — So careful of the type ; but no, From scarped cliff and quarried stone She cries “ a thousand types are gone ; I care for nothing, all shall go.” This is, in truth, what we must be- lieve, if, reasoning by analogy, we pass but one step higher in the scheme of creation. We know that Nature, wasteful of individual life, is equally wasteful of types of life. Must we not infer that she is no less wasteful of those aggregations of types which constitute the populations of worlds ? Watching her operations a few brief minutes, we might (setting experience aside) suppose her careful of individual life. Watching during a few generations, we should pro- nounce her careful of the type, though careless of individual life. But we perceive, when we extend the range of time through which we look, that she is careless no less of the type than of life. Why should this exten- sion of the range of view be the last we should permit ourselves ? If we pronounce Nature careful of the plane- tary populations, though careless of the types of life which make up such populations, we are simply declining to take a further step in the course pointed out for us by the teachings of analogy. Let us go over the ground afresh. Individual creatures, even the most favored, perish after a time, though the balance may long oscillate be- tween life and death. Weak, at first, each creature which is to live grows at length to its full strength, not with- out vicissitudes which threaten its ex- istence. As its life progresses the struggle continues. At one time the causes tending to decay seem to pre- vail a while ; at another, those which restore the vital powers. Disease is resisted again and again ; at first easily, gradually with greater diffi- culty, until at length death wins the day. So it is with types or orders of living creatures. A favored type, weak at first, begins after a while to thrive, and eventually attains its full- est development. But from time to time the type is threatened by dan- gers. Surrounding conditions be- come less favorable. It ceases to thrive, or, perhaps, passes through successive alternations of decay and restoration. At length the time comes when the struggle for existence ! can manifestly have but one end ; and then, though the type may linger long before it actually disappears, its 18 ILLUSIONS OF THE SENSES: disappearance is only a question of time. Now, it is true that each type thus flourishing for a while springs from other types which have disap- peared. The favored types of our age are but varieties of past types. Yet this does not show that types will continue to succeed each other in endless succession. For, if we con- sider the matter rightly, we perceive that the analogue of this circumstance is, in the case of individual life, the succession of living creatures genera- tion after generation. And as we know that each family, however large, dies out in the long run unless re- cruited from without, so we are to infer that the various types peopling this earth, since they cannot be re- cruited from without, must at length die out, though to our conceptions the time necessary for this process may appear infinite. To the student of science who rec- ognizes the true meaning of the doc- trine that force can be neither anni- hilated nor created, it will indeed ap- pear manifest that life must eventu- ally perish from the face of the earth ; for he perceives that the earth pos- sesses now a certain fund or store of force in her inherent heat, which is continually though slowly passing away. The sun also, which is a store-house whence certain forms of force are distributed to the earth, has only a finite amount of energy (though probably the inhabitants of the earth are less directly concerned in this than in the finiteness of terrestrial forces). Life of all kinds on the earth depends on both these stores of force, and when either store is ex- hausted life must disappear from the earth. But each store is in its nature limited, and must one day, therefore, be exhausted. We have also only to consider that life on the earth necessarily had a beginning to infer that it must neces- sarily have an end. Clearest evi- dence shows how our earth was once “ a fluid haze of light,” and how for countless aeons afterwards her globe was instinct with fiery heat, amidst which no form of life could be con- ceived to exist, after the manner of life known to us, though the germs of life may have been present “ in the midst of the fire.” Then followed ages in which the earth’s glowing crust was drenched by showers of muriatic, nitric, and sulphuric acid, not only intensely hot, but fiercely burning through their chemical activ- ity. Only after periods infinite to our conceptions could life such as we know it, or even in the remotest de- gree like what is now known to us, have begun to exist upon the earth. The reader, doubtless, perceives whither these considerations tend, and how they bear in an especial manner on the opinion we are to form respecting such planets as Jupiter and Saturn on the one hand and Mars on the other. We see our earth passing through a vast period, from its first existence as a separate member of the solar system, to the time when life appeared upon its surface : then began a comparatively short period, now in progress, during which the earth has been and will be the abode of life ; and after that must follow a period infinite to our conceptions when the cold and inert globe of the earth will circle as lifelessly round the sun as the moon now does. We may, if we please, infer this from analogy, seeing that the duration of life is always infinitely small by com- parison with the duration of the region where life appears ; so that, by anal- ogy, the duration of life on the earth would be infinitely short compared with the duration of the earth itself. But we are brought to the same con- clusion independently of analogy, per- ceiving that the fire of the earth’s youth and the deathly cold of her old age must alike be infinite in duration compared with her period of vital life- preserving warmth. And what is true of the earth is true of every mem- ber of the solar system, major planet, minor planet, asteroid, or satellite ; probably of every orb in space, from AND OTHER ESSAYS. 19 the minutest meteorite, to suns ex- ceeding our sun a thousandfold in volume. If we had any reason to suppose that all the planets sprang simultane- ously into being, that each stage of each planet’s existence synchronized with the same stage for every other planet, and that life appeared and disappeared at corresponding stages in the existence of every planet, we should be compelled to accept the theory that at this moment every planet is the abode of life. Not only, however, have we no reason to sup- pose that any one of these conditions exists (and not one but all these con- ditions must exist before that theory can be accepted), but we have the strongest possible evidence, short of actual demonstration, that the births of the different planets occurred at widely remote periods, and that the several stages of the different planets’ growth differed enormously in dura- tion ; while analogy, the only avail- able evidence on the third point, as- sures us that little resemblance can be supposed to exist between the con- ditions and requirements of life in different members of the solar sys- tem. On any reasonable hypothesis of the evolution of the solar system, the eight primary planets must have be- gun to exist as independent bodies at very different periods. If we adopt Laplace’s theory of the gradual con- traction of a mighty nebula, then we should infer that the planets were formed in the order of their distances from the sun, the remoter planets be- ing those formed first. And accord- ing to the conditions of Laplace’s hypothesis, the interval separating the formation of one planet from that of its next neighbor on either side must have been of enormous duration. If we prefer the theory of the gradual growth of each planet by processes of accretion, we should infer perhaps that the larger planets took longest in growing to maturity, or preferably that (according to the doctrine of probabilities) a process which for the whole system must have been of in- conceivably enormous length, and in which the formation of one planet was in no sort connected with the formation of any other, could not have resulted in bringing any two planets to maturity at the same or nearly the same time, save by so im- probable a combination of fortuitous circumstances as may justly be con- sidered impossible. If we consider that the solar system was evolved by a combination of both processes (the most probable theory of the three in my opinion), we must still conclude that the epochs of the formation of the different planets were separated by time-intervals so enormous that the duration of life upon our earth is, by comparison, as a mere second compared with a thousand years. Again, if we compare any two mem- bers of the solar system, except, per- haps Venus and the Earth, we cannot doubt that the duration of any given stage of the existence of one must be very different from that of the cor- responding stage in the other. If we compare, for instance, Mars with the Earth, or the Earth with Jupiter, and still more, if we compare Mars with Jupiter, we cannot doubt that the smaller orb of each pair must pass much more rapidly through the differ- ent stages of its existence than the larger. The laws of physics assure us of this, apart from all evidence af- forded by actual observation ; but the results of observation confirm the theoretical conclusions deduced from physical laws. We cannot, indeed, study Mars in such sort as to ascer- tain his actual physical condition. We know that his surface is divided into lands and seas, and that he possesses an atmosphere; we know that the vapor of water is at times present in this atmosphere ; we can see that snows gather over his polar regions in winter and diminish in summer : but we cannot certainly de- termine whether his oceans are like our own, or for the most part frozen ; the whitish light which spreads at times over land or sea may be due to 20 ILLUSIONS OF THE SENSES: clouds or to light snow-falls, for aught that observation shows us ; the at- mosphere may be as dense as our own or exceedingly rare ; the polar regions of the planet may resemble the earth’s polar regions, or may be whitened by snows relatively quite insignificant in quantity. In fine, so far as observation extends, the physi- cal condition of Mars may closely re- semble that of the earth, or be utterly dissimilar. But we have indirect ob- servational means of determining the probable condition of a planet smaller than the earth, and presumably older — that is, at a later stage of its exist- ence. For the moon is such a planet, and the telescope shows us that the moon in her decrepitude is oceanless, and'is either wholly without atmosphere or possesses an atmosphere of exceed- ing tenuity. Hence we infer that Mars, which, as an exterior planet, and much smaller than the earth, is prob- ably at a far later stage of its exist- ence, has passed far on its way to- ward the same state of decrepitude as the moon. As to Jupiter, though he is so much farther from us than Mars, we have direct observational evidence, because of the vast scale on which all the processes in progress on his mighty globe are taking place. We see that his whole surface is en- wrapped in cloud-layers of enormous depth, and undergoing changes which imply an intense activity (or, in other words, an intense heat) throughout his whole mass. We recognize in the planet’s appearance the signs of as near an approach to the conditions of the earth when as yet the greater part of her mass was vaporous, as is consistent with the vast difference necessarily existing between two orbs containing such unequal quantities of matter. Mars, on the one hand, differs from the earth in being a far older planet — probably, as respects the actual time which has elapsed since the planet was formed, and certainly as respects the stage of its career which it has now reached. Jupiter, on the other hand, differs from the earth in being a far younger planet — not in years perhaps, but in condition. As to the actual age of Jupiter we cannot form so probable an opinion as in the case of Mars. Mars being an ex- terior planet, must have begun to be formed long before the earth and being a much smaller planet, was probably a shorter time in attaining its mature growth. On both accounts, therefore, he would be much older than the earth in years ; while, as we have seen, his relative smallness would cause the successive stages of his career subsequent to his existence as an independent and mature planet to be much shorter. Jupiter, being exterior to Mars, presumably began to be formed millions of centuries be fore that planet, but his bulk and mass so enormously exceed those of Mars, that his growth must have re- quired a far longer time ; so that it is not at all certain that even in point of years Jupiter (dating from his ma- turity) may not be the youngest mem- ber of the solar system. But even if not, it is practically certain that, as regards development, Jupiter is far younger than any member of the solar system, save perhaps his brother-giant Saturn, whose greater antiquity and inferior mass (both sug- gesting a later stage of development) may have been counterbalanced by a comparative sluggishness of growth in the outer parts of the solar do- main. It is manifest from observed facts, in the case of Jupiter, that he is as yet far removed from the life-bearing stage of planetary existence, and theoretical considerations point to the same conclusion. In the case of Mars, theoretical considerations ren- der it extremely probable that he has long since passed the life-bearing stage, and observed facts, though, they do not afford strong evidence in favor of this conclusion, suggest noth- ing which, rightly considered, is op- posed to it. It "is true that, as we have shown in former essays on this planet, Mars presents many features of resemblance to our earth. This AND OTHER ESSAYS. 21 planet rotates in a period not differ- ing much from our day; his year does not exceed ours so greatly as to sug- gest relations unpleasantly affecting living creatures ; it has been shown that there are oceans on Mars, though it is not quite so clear that they are not for the most part frozen ; he has an atmosphere, and the vapor of water is at times present in that at- mosphere as in ours ; clouds form there ; snow falls, and perhaps rain from time to time ; ice and snow gather at the poles in winter, and are partially melted in summer ; the land surface must necessarily be uneven, seeing that the very existence of con- tinents and oceans implies that once, at any rate, the globe of Mars was subjected to forces resembling those which have produced the ir- regularities of the earth’s surface ; glacial action must still be going on there, even if there is no rain-fall, and therefore no denuding action cor- responding to that which results from the fall of rain on our terrestrial con- tinents. But it is a mistake (and a mistake too commonly made) to sup- pose that the continuance of those natural processes which are advanta- geous to living creatures, implies the existence of such creatures. The as- sumption is that the beneficent proc- esses of nature are never wasted according to our conceptions. Yet we see over and over again in nature not merely what resembles waste, what in fact is waste according to our ideas, but an enormous excess of wasted over utilized processes. The sun pours forth on all sides the sup- plies of light and heat which, where received as on our earth, sustain vegetable and animal life; but the portion received by our earth is less than the 2000 millionth, the portion received by all the planets less than the 230 millionth part, of the total force thus continually expended. And this is typical of nature’s opera- tions everywhere. The earth on which we live illustrates the truth as clearly as the sun. We are apt to say that it teems with life, forgetting that the region occupied by living creatures of all orders is a mere shell, while the whole interior mass of the earth, far larger in volume, and un- dergoing far more active processes of change — teeming, in fact, with energy — contains no living creature, or at least can only be supposed to contain living creatures by imagining condi- tions of life utterly different from those we are familiar with. The mere continuance, therefore, on Mars of processes which on the earth we associate with the existence of life, in reality proves nothing as to the continued existence of life on Mars. The surface of the moon, for example, must undergo disturbances, — mighty throes, as the great wave of sun-distributed heat circles round her orb once in each lunation, — yet few suppose that there is life, or has been for untold ages, on the once teeming surface of our companion planet. The formation of Mars as a planet must so long have preceded that of our earth, his original heat must have been so much less, his small globe must have parted with such heat as it once had so much more rapidly, Mars lies so much farther from the sun than our earth does, his atmosphere is so much rarer, his supply of water (the temperature-conserving element) is relatively as well as absolutely so much smaller, that his surface must be utterly unfit to support life in the remotest degree resembling the forms of life known on earth (save, of course, those lower forms which from the out- set we have left out of consideration). Yet at one time, a period infinitely re- mote according to our conceptions of time, the globe of Mars must have re- sembled our earth’s in warmth, and in being disturbed by the internal forces which cause that continual re- modeling of a planet’s surface with- out which life must soon pass away. Again, in that remote period the sun himself was appreciably younger; for we must remember that although, measured by ordinary time-intervals, the sun seems to give forth an unvary- ing supply of heat day by day, a real 22 ILLUSIONS OF THE SENSES : process of exhaustion is in progress there also. At one time there must have existed on Mars as near an ap- proach to the present condition of our earth, or rather to her general condi- tion during this life-supporting era of her existence, as is consistent with the difference in the surface gravity of the planets, and with other differences inherent as it were in their nature. Since Mars must also have passed through the fiery stage of planetary life, and through that intermediate period when, as it would seem, life springs spontaneously into being under the operation of natural laws not as yet understood by us, we can- not doubt that when his globe was thus fit for the support of life, life ex- isted upon it. Thus for a season, — enormously long compared with our ordinary time-measures, but very short compared with the life-support- ing era, of our earth’s career, — Mars was a world like our own, filled with various forms of life. Doubtless, these forms changed as the conditions around them changed, advancing or retrograding as the conditions were favorable or the reverse, perhaps de- veloping into forms corresponding to the various races of men in possession of reasoning powers, but possibly only attaining to the lower attributes of consciousness when the development of life on Mars was at its highest, thenceforth passing by slow degrees into lower types as the old age of Mars approached, and finally perish- ing as cold and death seized the planet for their prey. In the case of Jupiter, we are guided by observed facts to the con- clusion that ages must elapse before life can be possible. Theory tells us that this mighty planet, exceeding the earth three hundred times in mass, and containing five-sevenths of the mass of the whole system of bodies traveling around the sun, must still retain a large portion of its original heat, even if we suppose its giant orb took no longer in fashioning than the small globe of our earth. Theory tells us, moreover, that so vast a globe could not possibly have so small a density (less than one fourth the earth’s) under the mighty compressing force of its own gravity, unless some still more potent cause were at work to resist that tremendous compression — and this force can be looked for nowhere but in the intense heat of the planet’s whole mass. But observation shows us also that Jupiter is thus heated. For we see that the planet is surrounded by great cloud-belts such as our own sun would be incom- petent to raise, — far more so the small sun which would be seen in the skies of Jupiter if already a firmament had been set “in the midst of the waters.” We see that these belts undergo marvelous changes of shape and color, implying the action of ex- ceeding energetic forces. We know from observation that the region in which the cloud-bands form is exceed- ingly deep, even if the innermost re- gion to which the telescope penetrates is the true surface of the planet — while there is reason for doubting whether there may not be cloud-layer within cloud-layer, to a depth of many thousand miles, — or even whether the planet has any real surface at all. And, knowing from the study of the earth’s crust that for long ages the whole mass of our globe was in a state of fiery heat, while a yet longer period preceded this when the earth’s globe was vaporous, we infer from anal- ogy that Jupiter is passing, though far more slowly, through stages of his existence corresponding with ter- restrial eras long anterior to the ap- pearance of life upon the scene. We must, then, in the case of Jupi- ter, look to a far distant future for the period of the planet’s existence as a life-sustainer. The intense heat of the planet must in course of time be gradually radiated away into space, until at length the time will come when life will be possible. Then, doubtless, will follow a period (far longer than the life-sustaining portion of the earth’s existence) during which Jupiter will in his turn be the abode of life. It may be that before then AND OTHER ESSAYS. 23 the sun will have lost so large a pro- portion of heat that life in Jupiter will be mainly sustained by the planet’s inherent heat. But; more probably the changes in the sun’s heat take place far more slowly than the changes in the condition of any planet, even the largest. Possibly, even, the epoch when Jupiter will be a fit abode for life, will be so remote that the sun’s fires will have been recruited by the indrawing of the interior family of planets. For it must be remem- bered that the periods we have to deal with in considering the cooling of such an orb as Jupiter are so enor- mous, that not merely the ordinary time-measures, but even the vast pe- riods dealt with by geologists must be insignificant by comparison. Yonder is Jupiter still enwrapped in clouds of vapor raised by his internal heat, still seething, as it were, in his prime- val fires, though the earth has passed through all the first stages of her ex- istence, and has even long since passed the time of her maturity as a life-sustaining globe. It is no mere fancy to say that all the eras of Jupi- ter’s existence must be far longer than the corresponding terrestrial eras, since we actually see Jupiter in that early stage of his existence and know that the earth has passed through many stages toward the final eras of decay and death. It is, indeed impossible to form any opinion as to the probable condition of the sun or of the solar system when Jupiter shall become fit to support life, seeing that, for aught we know, far higher cycles than those measured by the planetary motions may be passed ere that time arrives. The sun may not be a solitary star but a member of a star-system, and before Jupiter has cooled down to the life-sustaining condition, the sun’s relation to other suns of his own system may have altered mate- rially, although no perceptible changes have occurred during the relatively minute period (a trifle of four thou- sand years or so) since astronomy began. In considering the case of Mars, I suggested the possibility that owing to the relative shortness of that planet’s life-sustaining era, the de- velopment of the higher forms of life may have been less complete than on our earth thus far (still less than the development of those forms on the earth in the coming ages). We may well believe that during the long pe- riod of Jupiter’s existence as a life- supporting planet, creatures far higher in the scale of being than any that have inhabited, or may hereafter in- habit, the earth, will be brought into existence. As the rule of nature on earth has been to advance from sim- ple to more complex forms, from lower types to higher, so (following the argument from analogy) we must suppose the law of nature to be else- where. And time being a necessary element in any process of natural de- velopment, it follows that where na- ture is allowed a longer time to ope- rate, higher forms, nobler types, will be developed. If this be so, then in Jupiter, the prince of planets, higher forms of animated conscious being will doubtless be developed than in any other planet. We need not, in- deed, point out that the supposition on which this conclusion rests is merely speculative, and that now, when the laws of natural develop- ment have so recently begun to ,be recognized and are still so imperfectly known, the argument from analogy is (in this particular case) necessarily weak. Nevertheless, analogy points in the direction we have indicated, and it is well to look outward and on- ward in that direction, even though the objects within the view are too remote for us to perceive their real forms. But, limiting our conclusions to those which may be justly inferred from known facts, let us inquire how the subject of life in other worlds presents itself when dealt with ac- cording to the relations above con- sidered. It is manifest at once that whether our new ideas respecting the present condition of Mars or Jupiter be cor- rect or not, the general argument de- 24 ILLUSIONS OF THE SENSES : ducible from the analogy of our own earth remains unaffected. If Mars and Jupiter be at this moment in- habited by living creatures, it can only be because these orbs happen to be passing through the life-supporting period of their existence. We have shown that there is strong reason for believing this not to be the case ; but if it is the case, this can only be re- garded as a strange chance. For we have learned from the study of our earth, that the life-supporting era of a planet is short compared with the duration of the planet’s existence. It follows that any time selected at ran- dom in the history of a planet is far more likely to belong to one or other of the two lifeless eras, one preceding, the other following the life-support- ing era, than to belong to this short era itself. And this present time is time selected at random with refer- ence to any other orb in the universe than our own earth. We are so apt to measure all the operations of na- ture by our own conceptions of them, as well in space as in time, that as the solar system presents itself (even now) as the center of the universe, so this present time, the era of our own life, or of our nation’s life, or of the life of man, or of the existence of or- ganic beings on the earth, or (passing yet a grade - higher) the era of our earth’s existence as a planet, presents itself to us as the central era of all time. But what has been shown to be false with respect to space is equally false with respect to time. Men of old thought that the petty re- gion in which they lived was the cen- ter of the universe. After this was shown to be false by Copernicus, Kepler, and Newton, men clung in turn to the conception that the solar system is central within the universe. The elder Herschel showed that this conception also is false. Even he, however, assigned to the sun a posi- tion whence the galaxy might be measured. But it begins to be rec- ognized that this is not so. Nay, not only is the sun no suitable center whence to measure the stellar system, but the stellar system is for us im- measurable. The galaxy has no cen- ter and no limits ; or rather we may say of it what Blaise Pascal said of the universe of space — its center is everywhere and its circumference no- where. The whole progress of mod- ern science tends to show that we must similarly extend our estimate of time. In former ages each genera- tion was apt to regard its own era as critical in the earth’s history ; that is, according to their ideas, in the his- tory of the universe itself. Gradually men perceived that no generation of men, no nation, no group of nations, occupies a critical or central position in the history of even the human race upon earth, far less in the history of organic life. We may now pass a step higher, and, contemplating the infinity of time, admit that the whole duration of this earth’s existence is but as a single pulsation in the mighty life of the universe. Nay, the duration of the solar system is scarcely more. Countless other such systems have passed through all their stages, and have died out, untold ages before the sun and his family began to be formed out of their mighty nebula ; countless others will come into being after the life has de- parted from our system. Nor need we stop at solar systems, since within the infinite universe, without begin- ning and without end, not suns only but systems of suns, galaxies of such systems, to higher and higher orders endlessly, have long since passed through all the stages of their exist- ence as systems, or have all those stages yet to pass through. In the presence of time-intervals thus seen to be at once infinitely great and infi- nitely little — infinitely great compared with the duration of our earth, infi- nitely f little by comparison with the eternities amidst which they are lost — what reason can we have when viewing any orb in space from our little earth, for saying now is the time when that orb is, like our earth, the abode of life ? Why should life on that orb synchro- nize with life on the earth ? Are not. AND OTHER ESSAYS. 25 - on the contrary, the chances infinitely great against such a coincidence ? If, as Helmholtz has well said, the dura- tion of life on our earth is but the mi- nutest “ ripple in the infinite ocean of time,” and the duration of life on any other planet of like minuteness, what reason can we have for supposing that those remote, minute, and no way associated waves of life must needs be abreast of each other on the infinite ocean whose surface they scarcely ripple ? But let us consider the conse- quences to which we are thus led. Apart from theoretical considerations or observed facts, it is antecedently improbable that any planet selected at random, whether planet of our own system, or planet attending on another sun than ours, is at this present time the abode of life. The degree of im- probability corresponds to the pro- portion between the duration of life on a planet, and the duration of the planet’s independent existence. We may compare this proportion to that existing between the average life-time of a man and the duration of the hu- man race. If one person were to select at ran- dom the period of a man’s life, whether in historic, prehistoric, or future time, and another were to select an epoch equally at random, save only that it fell somewhere within the period of the duration of the human race, we know how exceedingly minute would be the probability that the epoch se- lected by the second person would fall within the period selected by the first. Correspondingly minute is the a priori probability that at this pres- ent epoch any planet selected at random is the abode of life. This is not a mere speculation, but an abso- lute certainty, if we admit as certain the fact, which few now question, that the period during which organic existence is possible on any planet is altogether minute compared with the duration of that planet’s exist- ence. The same relation is probably true when we pass to higher systems. Regarding the suns we call “ the stars ” as members of a siderial sys- tem of unknown extent (one of in- numerable systems of the same order), the chance that any sun selected at random is, like our own sun at the present time, attended by a planetary system in one member of which at least life exists, is exceedingly small, if, as is probable, the life-supporting era of a solar system’s existence is very short compared with the inde- pendent existence of the system. If the disproportion is of the same order as in the case of a single planet, the probability is of the same order of minuteness. In other words, if we select any star at random, it is as un- likely that the system attending on that sun is at present in the life-bear- ing stage as a system, as it is that any planet selected at random is at pres- ent in the life-bearing stage as a planet. This conclusion, indeed, may be regarded as scarcely less cer- tain than the former, seeing that we as little doubt the relative vastness of the periods of our sun’s existence before and after his existence as a supporter of life, as we doubt the relative vast- ness of the periods before and after the life-supporting era of any given planet. There is, however, one ele- ment of doubt in the case of the star. The very fact of the star’s ^existence as a steady source of light and heat implies that the star is in a stage re- sembling that through which our own sun is now passing. It may be, for instance, that the prior stages of solar life are indicated by some degree of nebulosity, and the later stages by irregular variations, or by such rapid dying out in brightness as has been observed in many stars. Yet a sun must be very nebulous indeed — that is, must be at a very early stage in its history — for astronomers to be able to detect its nebulosity ; and, again, a sun must long have ceased to be a life-supporter before any signs of decadence measurable at our remote station, and with our in- significant available time-intervals for comparison, are manifested. 26 ILLUSIONS OF THE SENSES: As to higher orders than systems of suns we cannot speculate, because we have no means of determining the nature of such orders. For in- stance, the arrangement and motions of the only system of suns we know of, the galaxy, are utterly unlike the arrangements and motions of the only system of planets we know of. Quite possibly systems of sun-sys- tems are unlike either galaxies or solar systems in arrangement and motions. But if, by some wonderful extension of our perceptive powers, we could recognize the countless millions of systems of galaxies doubt- less existing in infinite space, with- out, however, being able to ascertain whether the stage through which any one of those systems was passing corre- sponded to the stage through which our galaxy is at present passing, the probability of life existing anywhere within the limits of a galaxy so se- lected at random would be of the same order as the probability that life exists either in a planet taken at ran- dom, or in a solar system taken at random. For though the number of suns is enormously increased, and still more the number of subordinate orbs like planets (in posse or in esse), the magnitude of the time-intervals concerned is correspondingly in- creased. One chance out of a thou- sand is as good as a thousand chances out of a million, or as a million out of a thousand millions. Whether we turn our thoughts to planet, sun, or galaxy, the law of Nature (recognized as universal within the domain as yet examined), that the duration of life in the individual is indefinitely short compared with the duration of the type to which the individual be- longs, assures us, or at least renders it highly probable, that in any mem- ber of any of these orders taken at ramdom, it is more probable that life is wanting than that life exists at this present time. Nevertheless, it is at least as probable that every member of every order — planet, sun, galaxy, and so onward to higher and higher orders endlessly — has been, is now , or will hereafter be, life- supporting “ after its kind In what degree life-supporting worlds, or suns, or systems are at this or any other epoch surpassed in number by those which as yet fulfill no such functions or have long since ceased to fulfill them, it would only be possible to pronounce if we could determine the average degree in which the life-sustaining era of given orbs or systems is surpassed in length by the preceding and following stages. The life-sustaining orbs or systems may be surpassed many thousandfold or many millionfold in number by those as yet lifeless or long since dead, or the disproportion may be much less or much greater. As yet we only know that it must be very great indeed. But at first sight the views here ad- vanced may appear as repugnant to our ordinary ideas as Whewell’s belief that perhaps our earth is the only in- habited orb in the universe. Millions of uninhabited worlds for each orb which sustains life ! surely that im- plies incredible waste ! If not waste of matter, since according to the the- ory every orb sustains life in its turn, yet still a fearful waste of time. To this it may be replied, first, that we must take facts as we find them. And secondly, whether space or matter or time or energy appear to be wasted, we must consider that, after all, space and matter and time and energy are necessarily infinite, so that the portion utilized (according to our conceptions) being a finite portion of the infinite is itself also in- finite. Speaking, however, on the subject we are upon, if one only of each million of the orbs in the uni- verse is inhabited, the number of in- habited orbs is nevertheless infinite. Moreover, it must be remembered that our knowledge is far too imper- fect for us to be able to assert confi- dently that space, time, matter, and force, though not utilized according to our conceptions, are therefore neces- sarily wasted. To the ignorant sav- age, grain which is planted in a field AND OTHER ESSAYS. 27 instead of being used for food, seems wasted, the wide field seems wasted, the time wasted during which the grain is growing and ripening into harvest ; but wiser men know that what looks like waste is in reality economy. In like manner the sun’s rays poured on all sides into space so that his circling family receives but the 230 millionth portion, seem, to our imperfect conceptions, almost wholly wasted ; but, if our knowledge were increased, we should perhaps form a far different opinion. So it may well be with the questions which per- plex us when we contemplate the short duration of the life-sustaining condition of each world and sun and galaxy compared with the whole exist- ence of these several orders. The arrangement which seems so wasteful of space and time and matter and force, may in reality involve the most perfect possible use and employment of every portion of space, every in- stant of time, every particle of matter, >every form of force. EARTHQUAKES. It is related in the Timceus of Plato that the ancient Egyptians held the world to be liable to occasional widely-extended catastrophes, by which the gods checked the evil pro- pensities of men, and cleansed the earth from guilt. Conflagrations, deluges and earthquakes were the instruments of the wrath of the offended gods. After each catastro- phe mankind were innocent and happy, but from this state of virtue they gradually fell away, until their accumulated offences called for new judgments. Then the gods took counsel together, and unable to bear with the multiplied iniquities of the human race, swept them from the earth in some great cataclysm, or sent a devouring flame to consume them, or shook the solid earth until hills and mountains fell upon and crushed the inhabitants of the whole world. One can understand how the con- fused records of great catastrophes, in which all, or nearly all, the inhabi- tants of wide districts were destroyed, led in the course of time to the forma- tion of such views as Plato has de- scribed. And, indeed, it is not in one nation alone that we find theories of this sort prevalent. In the Institute of Menu the Hindoos are taught that at the end of each of those cycles of ages which are termed the “ days of. Brahma,” all forms of life are de- stroyed from the earth by a great conflagration, followed by a deluge which inundates heaven itself. The mythical legends of the Chinese refer to similar views, which appear also in the Babylonian and Persian cosmog- onies. The Chaldeans taught that when the planets are all conjoined in Capricorn the earth will be over- whelmed by a flood, and that when a conjunction of this sort takes place in Cancer the earth will be destroyed by fire. In the present age when the net- work of telegraphy brings all parts of the earth into close intercommunica- tion, we are not likely to trace, even in the most widespread disasters, the approaching destruction of our globe. The same day which brings the intel- ligence of some desolating catastro- phe brings evidence also that the devastation is but local. We are seldom informed of simultaneous, or nearly simultaneous, events happening in widely-separated regions of the earth’s surface. Accordingly, we are seldom led to dread the occurrence of any widely-devastating series of catastrophes. We have heard a great deal lately of certain speculations — recently ven- tilated by an American philosopher — which threaten the earth with com- plete annihilation. According to these views there is one great danger to which we are at all times liable — the risk, namely, that some large volcanic vent should be formed be- neath the bosom of ocean. Through 28 ILLUSIONS OF THE SENSES: this vent the sea would rush into the interior of the earth, and being forth- with converted into steam by the intense subterranean heat, would rend the massive shell on which we live into a thousand fragments. Whether it is possible or not that such an event as this should take place, I shall not here stay to inquire. Let it suffice that the risk — if there be any — is no greater now than it has been any time during thousands of past years. But certainly, if there is any source from which the inhabitants of the earth may reasonably dread the oc- currences of widely devastating catas- trophes, it is from earthquakes. It is related that for full six months after the great earthquake of Lisbon, Dr. Johnson refused to believe in the occurrence of so terrible a catastro- phe. “ He spoke half jestingly,” Macaulay thought — it is not easy to see on what grounds. To us it seems far more probable that Johnson heard with natural wonder and awe of the destructive effects of this fearful con- vulsion ; and that for awhile he could scarcely believe that the extent of the disaster had not been exaggerated. It would be well if, indeed, the powers of earthquakes were less tre- mendous than they have been repeat- edly shown to be. “ There is,” says Humboldt, “ no other outward mani- festation of force known to us — the murderous inventions of our own race included — through which, in the brief period of a few seconds or minutes, a larger number of human beings have been destroyed than by earthquakes.” Lightning and storm, war and plague, are but weak and inefficient agents of destruction in comparison with the earth’s internal forces. And as earthquakes surpass all other phenomena as agents of sudden destruction, so the impression which they produce on those who for the first time experience their effects is peculiarly and indescribably awful. Men of reputed courage speak of a feeling of “intolerable dread” pro- duced by the shocks of an earthquake, “ even when unaccompanied by sub- terranean noises.” The impression is not that of simple fear but a feeling of absolute pain. The reason seems for awhile to have lost the power of separating real from imaginary causes of terror. The lower animals, also, are thrown into a state of terror and distress. “ Swine and dogs,” says Humboldt, “ are particularly affected by the phenomenon of earthquakes.” And he adds that “ the very crocodiles of the Orinoco, otherwise as dumb as our little lizards, leave the shaken bed of the stream and run bellowing into the woods.” Humboldt’s explanation of the pe- culiar sensations of alarm and awe produced by an earthquake upon those who for the first time experi- ence the effects of the phenomenon is in all probability the correct one. “The impression here is not,” he says, “the consequence of the recol- lection of destructive catastrophes presented to our imagination by nar- ratives of historical events ; what seizes us so wonderfully is the dis- abuse of that innate faith in the fixity of the solid and sure-set foundations of the earth. From early childhood we are habituated to the contrast between the mobile element water and the immobility of the soil on which we stand. All the evidences of our senses have confirmed this belief. But when suddenly the ground begins to rock beneath us, the feeling of an unknown mysterious power in nature coming into operation and shaking the solid globe arises in the mind. The illusion of the whole of our earlier life is annihilated in an instant.” Use habituates the mind to the shocks of earthquake. Humboldt found himself able after awhile to give a close and philosophic scrutiny to the circumstances attending the phe- nomenon which had at first impressed him so Startlingly. And he tells us that the inhabitants of Peru think scarcely more of a moderate shock of earthquake than is thought of a hail- storm in the temperate zone. AND OTHER ESSAYS. 29 Yet the annals of earthquakes are sufficient to give rise to a feeling of dread, founded, not merely on the novelty of the event, but on a knowl- edge of the powers of the earth’s internal heavings. The narratives of some of the great earthquakes afford fearful evidence on this point. In the first shock of the great earthquake of Lisbon (November, 1755) the city was shaken to its foun- dations. The houses were swung to and fro so violently that the upper stories fell at once, causing a terrible loss of life. Thousands rushed to the great square in front of St. Paul’s Church, to escape the reach of the tottering ruins. It was the festival of All Saints, and all the churches had been crowded with worshippers. But when the terrified inhabitants reached the square, they found that the great church of St. Paul’s was already in ruins, and the immense multitude which had thronged its sacred pre- cincts were involved in its destruction. Such of the congregations of the different churches as had escaped rushed to the banks of the Tagus for safety. There were to be seen priests in their -sacerdotal vestments, and an immense crowd of people of all ranks and ages, praying to Heaven for mercy. As they prayed there came the second shock, scarcely less terrible than the first. The church on the top of St. Catherine’s Hill was rocked to and fro till it fell, crushing in its fall a great multitude which had sought that height for safety. But a far more terrible catastrophe was at hand. As the banks of the river sounded with the Miserere of the terrified supplicants who had crowded thither for safety, there was seen to pass over the wide expanse of the stream (here four miles broad) a strange heaving swell, though no wind stirred the air. The waters seemed to be drawn away to meet a vast wave which was now first observed to be bearing down upon the devoted crowd. They strove to fly, but the wave swept too rapidly onwards. The whole multitude was overwhelmed in a moment. A magnificent quay, lately built at a great expense, was engulfed with all who had crowded on it for refuge. Numberless vessels, also, which were anchored on the river and were now full of terrified people — seeking on an unstable ele- ment the security which the solid earth denied them — were sucked down by the tremendous wave, and not a trace of them was ever afterwards seen. A third shock followed, and again the river was swept by a gigantic wave. So violently was the river moved that vessels which had been riding at an- chor in deep water were flung upon the dry ground. Other shocks and other inroads of the river-water fol- lowed, each working fresh destruction, insomuch that many began to believe that “ the city of Lisbon was doomed to be entirely swept away from the face of the earth. ” It would be out of place to describe here at length how fire and pestilence came successively to complete the des- olation begun by the earthquake’s ravages. The terrible story has been narrated elsewhere. But what re- mains to be mentioned gives us start- ling evidence of the terrible energy of the earth’s subterranean forces : — The mountains Arrabida, Estrella, Julio, Marvan, and Cintra, some of the largest in Portugal, were shaken from their very foundations, they opened at their summits, and huge masses were flung into the neighboring valleys. Flames and smoke were emitted from the openings. But much farther away the effects of the great convulsions were experienced. It has been com- puted, says Humboldt, that a portion of the earth’s surface four times greater than the whole extent of Europe was simultaneously shaken. On the coast of Sweden and on the shores of the Baltic, far away across the Atlantic to the Antigua Islands, at Barbadoes and Martinique, and still further off in the great Canadian lakes, the movement was sensibly felt. Avast wave of inky blackness swept over the West Indian seas, rising twenty feet above the level of the highest tides. In Algeria the 30 ILLUSIONS OF THE SENSES : earth was as violently shaken as in Portugal, and eight leagues from Mo- rocco a village with 8000 inhabitants was swallowed up. The shocks felt at sea were so vio- lent that the captains who experienced them thought their ships had struck the solid ground. A ship 120 miles to the west of St. Vincent was so vio- lently shaken that the men were thrown half a yard perpendicularly upwards from the deck. Lakes and rivers in England were strangely agitated. The water in Loch Lomond suddenly rose against the banks without appar- ent cause, and then as suddenly sub- sided — the vibration of the earth’s surface having traveled from Lisbon to Scotland at the rate of twenty miles a minute ! It has been calculated that in Lis- bon alone 60,000 persons perished within the brief space of six minutes. But there have been other earthquakes in which even this terrible destruction of life has been surpassed. In 1603, 100,000 persons fell victims to the great Sicilian earthquake, and upwards of 300,000 persons are supposed to have perished in the great earthquakes which desolated Antioch in the sixth and seventh centuries. It has been estimated that within the last 4,000 years five or six millions of human be- ings have perished through the effects of earthquakes. It is related that in the great earth- quake of 1747 all the inhabitants of the town of Callao were destroyed, save one. The man who escaped, standing on a fort which overlooked the harbor, saw the sea retire to a dis- tance and then return like a vast moun- tain in height. “He heard a cry of Miserere rise from all parts of the city,” and in a moment all was silent — where the town had once flourished there was a wide sea. But the same wave which overwhelmed the town drove past him a small boat, into which he flung himself, and so was saved.* * It must be remarked, however, that Sir Charles Lyell estimates the number of the saved at 200, “ of whom twenty-two were OUR DUAL BRAIN. In a recent lecture at the Royal In- stitution, Mr. Horsley offered evi- dence (which seems to me not very strong) against the theory of the dual- ity of the mind. A person who, be- ing already fairly well able to draw with either hand separately, attempts to draw simultaneously two different forms, however simple, with both hands, is tolerably sure to fail. Mr. Horsley appears to think that failure always results. When the effort is made, he says, “ There is a very def- inite sensation in the mind of a con- flict that is going on in the cortex of the brain. The idea of the circle al- ternates with that of the triangle, and the result of this confusion in the in- tellectual and sensorial portions of the brain is that both motor areas, though remembering, as it were, the determination of the experimenter to draw distinct figures, produce a like confused effect, namely, a circular tri- angle and a triangular circle.” Mr. Horsley adds that if the draw- ing is commenced immediately at the sound of a signal (as should always be done in such experiments), it will be found that the triangle predomi- nates, while, on the other hand, if the two figures are not commenced simul- taneously, the one last begun will ap- pear most distinctly in the fused re- sult, in fact, will very markedly pre- dominate. He reasons upon this as follows : — “ The idea of a triangle and circle having been presented to the: intellect of the sensory centers, the voluntary effort to reproduce them is. determined upon : now if we had a dual mind, and if each hemisphere was capable of acting per se f then we should have each intellectual area, sending a message to its own motor area, with the result that the two fig- ures would be distinct and correct, not fused.” To this experimental evidence and to its interpretation two different an- saved on a small fragment of the fort of Vera Cruz, which remained as the only memorial of the town after this dreadful inundation.” AND OTHER ESSAYS. 31 swers can be given. In the first place, it does not always happen that the at- tempt to draw two different objects simultaneously fails in the alleged manner. Setting on one side as prob- ably exaggerated the story that Sir Edwin Landseer drew on one occa- sion a deer’s head with one hand, while he was drawing a landscape with the other, I may cite from my own experience a case which entirely invalidates Mr. Horsley’s evidence. My friend, Professor Edwin Morse, of Salem, Mass., could draw simulta- neously, and that, too, before an au- dience, two different objects with either hand. Or, he would draw an object with one hand, and at the same time write the names of the parts of the object with the other. With prac- tice much skill may be acquired in this ambidextrous work. Here is a simple experiment to show the effect of practice. Try for the first time to write a word of so many letters while you spell aloud, letter by letter, another word contain- ing the same number of letters. At first you are almost sure (perhaps quite sure) to fail. But after a few trials what had seemed impossible be- comes feasible, and presently it be- comes quite easy. Then, even if it were proved that we cannot do two different things at once (apart from cases where either or both is done automatically), this would no more prove that the brain is not dual than our inability to use the two eyes simultaneously to do differ- ent work would prove that we have not dual vision. As a matter of fact we are able to prove very easily that vision is double, by alternately closing and opening either eye. We cannot make any cor- responding experiment with the brain. We do not know even that, when we are trying to do simultaneously two different things the two different sides of the brain are called into action. We have positively no means of de- termining whether one side, or the other side, or both sides of the brain shall be used, or of knowing whether they are used. Even in those cases where marked alternations of charac- ter, accompanied or preceded by marked cerebral phenomena, show unmistakably that two different parts of the brain may alternate in the reg- ulation of actions and even of char- acter, the person thus dually minded and charactered is perfectly power- less as to the particular mental side of him which shall come uppermost (or act alone)* He often does not even know that he is passing or has passed from one state to the other. Since, however, we are absolutely certain that each eye does its work,, while we are absolutely unable to make them work separately yet sim- ultaneously — to make one eye work at long range, for example, and the other at short range, the argument used by Mr. Horsley in regard to the brain is altogether without force. If any one could make his two eyes, work separately, I should be the one to do it, for my left eye is perma- nently limited to work at short focal distances, while the right eye has the usual range. Yet, not only am I powerless to make my two eyes work separately and simultaneously, but I am very seldom conscious of the fact that the left eye is in reality present- ing to the brain (so to speak) a very different picture from that which is presented by the right eye. I remained unconscious of the dif- ference between the focal lengths of my two eyes, marked though it is (in- somuch, that for ordinary distances my left eye is almost blind), till I was about twenty ; at least I know it must have been more than twenty-six years ago that I detected the peculiarity. I was in church one Sunday evening, listening or not listening to a rather dreary sermon, in which a person whom I had reason for regarding little was enjoining duties which I had long learned to regard a great deal ; and being naturally inattentive to him, I attended to other things. Now, there were in front of me two bright lights, and I noticed to the right of them two blurred lights, looking as large as. 32 ILLUSIONS OF THE SENSES: the moon, where assuredly no lights were. I looked at another group of lights, three of them — and lo, to the right of them also, a group of three, similarly arranged, blurred lights. I closed my left eye, and could see only the bright lights ; I closed my right eye and could see only the blurred lights. That was all my left eye could do in the way of showing those lights. Thus, for the first time in my life, I learned that so far as distant ob- jects were concerned I was almost blind of one eye. But I soon found that my left eye was by no means blind for near objects ; on the con- trary, it was and is very keen for them. Yet I cannot make my eyes, different though they thus are, work separately, except in an imperfect sort of way, akin to the way in which, in Mr. Horsley’s experiment, one hand makes a circular triangle while the other makes a triangular circle. I am well assured my vision is double, as- all men are; nay, in my case vision is even of two kinds with the two eyes : yet I have precisely the sort of evidence respecting my two eyes which Mr. Horsley regards as evi- dence of unity. Mr. Horsley cites a singular illus- tration of the duality of the mind, of which, however, he endeavors to dis- pose. The case is so remarkable, and, just now when all sorts of foolish superstitions are as rife as ever, so in- structive, that I give its details here pretty nearly in full, as recorded by Prof. Ball, of Paris. He tells us that a young man, a patient of his, one morning heard himself addressed by name, and yet could see no one. He replied to this invisible, and in reality imaginary, interlocutor ; and a con- versation followed, in the course of which the ghostly visitor informed him that he — the visitor — rejoiced in the name of Gabbage. After this, he was often favored with visits from M. Gabbage. Unfortunately, the sugges- tions of M. Gabbage were generally open to objection. At one time M. Gabbage urged the patient to give an overdose of chlorodyne to a friend’s child ; at another, his idea was that the young man would do well to jump out of a second-floor window. Prof. Ball thought — naturally enough — that the young man needed watching. It was presently found that the patient was suffering from one-sided hallucination ; that is to say, a strong but false impression, af- fecting one side only of the brain, ap- peared to come from some external cause, the healthy side rejecting the evidence as false. (Without doubt many superstitions, many false relig- ious beliefs, and also many crimes, have been suggested in this way.) Mr. Horsley finds nothing in this or similar cases to suggest the duality of the brain ; but I take it that the evidence is precisely analogous to that which showed me not only the duality but the diversity of my own visual powers. Usually, of course, the two sides of the brain would give the same sort of evidence respecting external objects ; just as — usually — the two eyes do : but in certain cases one side of the brain is defective or peculiar in some way or other, and so gives evidence which the better and sounder side rejects ; just as in my case one eye gave evidence of large diffuse lights where I knew, from the sound evidence of my better eye, that small bright flames were burning. The analogy seems as perfect as it can be ; and the necessary conclusion is that the brain’s action, in ordinary cases, is as essentially dual as the ac- tion of the eyes in vision. A NEW STAR IN A STAR CLOUD. The discovery of a new star in the midst of the Great Nebula in Androm- eda must be regarded as one of the most remarkable astronomical events of the age. It is true that great changes have ere now been recognized in stars lying within nebulous clouds. The star Eta Argfis for example, which lies in the midst of that wonderful AND OTHER ESSAYS. 33 mass of luminous gas called the Key- hole Nebula in Argo, has changed so marvelously in luster since it was first catalogued as a fourth magnitude star as to present a case correspond- ing so far as the star is concerned with the sudden appearance of the new star in the Andromeda Nebula. For Eta Argus sank from the fourth magnitude to the sixth, then rose rap- idly to the second, and after remain- ing for some time at that magnitude increased almost suddenly in splendor until it rivaled Canopus and was sur- passed only by Sirius. Undoubtedly to an observer set at such a distance that Eta Argus when thus resplendent would have appeared only as an eighth magnitude star, like the new star in Andromeda, Eta with its pres- ent light of a sixth magnitude star would be altogether invisible. So that viewed from that imagined dis- tance Eta Argus when it rose to its greatest splendor would have appeared as a new star, and as it faded out of view would come to be regarded as having been but a temporary star. Again, the star which appeared in Cygnus in 1876 must be regarded as a star which had suddenly shone out in a nebula, although no nebula had been known where the star appeared. For when that star had disappeared there still remained a blue planetary nebula in the place which the star had occupied. And this nebula was and is so faint that one can readily understand it having escaped notice before. No one, I imagine, can doubt that the nebula which is seen there now existed there before the star ap- peared. The stars in the great Fish-mouth Nebula in Orion exhibit also a certain degree of variability, which, though not so striking as the appearance of “new stars,” is in reality a phenome- non of the same sort. For every so- called “new star” may be regarded as a variable of an unusually irregular kind. But in all these cases the star which shone with variable luster, or which for a time appeared as a new star, has been in the midst of a gaseous nebula. The great nebula in Andromeda has always been regarded as a stellar neb- ula, although it has never been resolved into stars. Under spectroscopic ex- amination it presents the rainbow- tinted streak crossed by absorption lines which indicates the existence of glowing solid or liquid or highly com- pressed vaporous matter shining through absorptive vapors. I remem- ber Dr. Huggins describing the spec- trum of this object to me, during a visit which I paid to his observatory in 1866 ; and he then said that the spectrum differed only from that of a star, in being rather sharply cut off at the red end, as if through the action of vaporous envelopes more powerfully absorptive of red light than the vapors around our sun and most other stars. In a rather carelessly-written para- graph in the Times of Saturday last,* manifestly by a person not well ac- quainted with astronomical facts, the new star is spoken of as if it gave support to Laplace’s nebular theory. In reality the appearance of the star is most strongly opposed to that the- ory, for the simple reason that all the processes involved in Laplace’s nebu- lar theory are slowly-acting ones, while the appearance of a new star where a star had not before been visible, sig- nifies events of a catastrophic nature. Moreover the theory of Laplace, in the form in which it was presented, cannot be maintained by any one ac- quainted with the laws of physics. A vast disc of gaseous matter, extending beyond the orbit of Neptune, but con- taining no more matter than there is in the whole solar system would not have the slightest cohesion among its various parts. To conceive of it as rotating like a single mass is to im- agine the impossible. One may say indeed of Laplace’s nebular hypothe- sis — which was very properly regarded by himself as but a guess — that as- tronomers suppose it physically pos- sible and physicists suppose it astro- * This article was first published Sept, n, 1885. 34 ILLUSIONS OF THE SENSES : nomically possible : but no one who combines a knowledge of both astron- omy and physics can accept it in the wide generality of its original form. What the new star really does throw light upon, and light of a very clear and unmistakable sort, is not the the- ory of the solar system, but the theory of the stellar system — that grand gath- ering of stars, star clusters, star-clouds, and star-streams, which we call the galaxy. If there was one member of the family of nebulae which was still sup- posed to remain possibly an external galaxy, after all the evidence which had been collected to show that neb- ulae belong to our own galaxy, it was the great nebula in Andromeda, — the transcendently beautiful queen of the nebulae as the old astronomers enthu- siastically called it. Mr. Herbert Spencer observed as far back as 1859 or i860, in his fine essays on the Neb- ular Hypothesis in the Westminster Review, that the theory according to which numbers of the resolvable neb- ulae are external star systems is abso- lutely untenable. He pointed to this fatal objection, that Sir William Her- schel’s most powerful telescopes failed to resolve the remoter portions even of our own galaxy. How then could they — or indeed in many cases much weaker telescopes — by any possibility resolve galaxies lying far beyond its limits. A resolvable nebula which has an apparent greatest diameter of a quarter of a degree of arc, would be a very large one indeed ; yet even one of that apparent size must lie at a dis- tance exceeding its own diameter about 230 times, and exceeding there- fore (supposing that nebula a galaxy like our own in size) the distance of the outskirts of our galaxy from us, more than 450 times. This would correspond to a diminution in the lus- ter of individual stars more than 200,- 000 times. Now Herschel had to withdraw from the survey of the re- motest parts of our galaxy, or at any rate the least resolvable parts (for my own interpretation of their irresolva- bility does not assume great distance 1 as a necessary point), satisfied, as he said, that those depths are unfathom- able. Irresolvable nebulosity foiled his most powerful telescopes, within the limits of our own stellar domain. How preposterous, then, when consid- ered a little, the belief that the same telescope which failed to resolve the outskirts of our own galaxy, can bring into view individual stars having less than the 200,000th part of the light of those remoter suns of our stellar system. Mr. Herbert Spencer pointed out another fatal objection, in Sir W. Her- schel’s own account of the arrange- ment of the stellar and nebular group- ings. For Herschel said that when- ever he found his star gauges running poor, he would call out to his elder sister, Miss Caroline Herschel, who acted as his assistant, “ Prepare to write, nebulae are about to appear.” This peculiarity of arrangement by which nebulae fit in where stars are sparsely strewn, and vice versa , must be regarded as proof positive of the association between nebulae and stars. Nebulae must belong, then, to our gal- axy. I myself collected some forty pieces of evidence as to the structure of our galaxy, by which, as I believe, the old- fashioned theory (in favor of which not a single direct argument has ever been adduced) was shown to be ab- solutely untenable. I may remark in passing that I propose to publish in the first monthly number of the new series of Knowledge a letter which I addressed to Sir John Herschel in 1870, wherein the greater number of the arguments on which the objections to the old theory are based were briefly indicated. In the second num- ber of that series I propose to publish his singularly interesting reply to that communication. I feel that the time has come to make known precisely how that great astronomer viewed the questionings then being addressed to the theory with which — not quite cor- rectly — his own name and his father’s have been associated. But while Mr. Spencer’s objections AND OTHER ESSAYS. (of themselves) sufficed to demonstrate the utterly untenable nature of the theory of galaxies of stars external to our own stellar system ; and my own more labored gathering of evidence on the subject should have left no doubt, even in the minds of those least ready to recognize the force of reason- ing in such matters, the great nebula in Andromeda was in some degree outside our evidence. The Andromeda nebula is not gas- eous but manifestly stellar ; yet it has not been resolved into stars. Nor had it been possible to show how far the nebula was from resolvability. Some, using very powerful telescopes on the nebula, supposed they had come very near to resolving it into discrete stars ; but they could not feel sure on such a point. For anything yet shown, telescopes a thousand times more powerful than the great Rosse telescope (imagined for the moment as perfect in defining power) might have failed to resolve the Andromeda nebula into stars. Therefore Mr. Herbert Spencer’s first objection, fatal against all re- solved or partly-resolvable nebulae, had no fatal force (it had considerable force however) against the Andromeda nebula. Of course the other objection had no force at all if this nebula is once regarded as exceptional. Among all my own objections against the theory of external galaxies, few had much force against the Queen of the Nebulae, and certainly none were ab- solutely decisive against this great ag- glomeration of unquestionably stellar material being an external galaxy. Now, however, it need hardly be said, the question is disposed of. A star-cloud cannot possibly be an ex- ternal galaxy resembling our sun if there can appear in it suddenly a star where no star had before been seen. Were the Andromeda nebula such a galaxy the change which has recently taken place in it (or to speak more precisely, the change of which the light-brought news has recently reached us) would correspond to such a change in our galaxy as would alter 35 its whole character. A star millions of times larger than any orb in our galaxy would have to be present in it — to begin with — and then after being so dull as to give no more light than an ordinary sun — would have to blaze out suddenly with hundreds of thou- sands of times as much light even as the splendid Sirius pours forth, to pro- duce such a change of aspect in our galaxy, supposed to be seen from the distance of the Andromeda nebula, as has actually taken place in that star- cloud. The theory that the star-clouds, or any of them, are external galaxies has received a death-blow. This is not saying it was not dead before. The blow may be such a one as Falstaff gave the dead Percy : but no one can mistake its force. With this new wound the theory has no longer even the semblance of life, and will possi- bly disappear ere long from those cemeteries for defunct theories, the text-books ! MONSTER SEA-SERPENTS. I have been gratified and rather amused to find a short article, which I contributed more than a year since to The Newcastle Weekly Chronicle on the subject of a marine monster seen near Panama, appearing in the very valuable report of Professor Spencer F. Baird, United States Commissioner of Fish and Fisheries. A genial arti- cle in the New York Tribune for J an- uary 4, 1885, presents my recognition of this marine monster and defence of the sea-serpent as a tardy admission on the part of science that there may be more things in sea and land than had been dreamt of in an unphilo- sophical philosophy. But so far as I am concerned there has been no “ ridicule, followed by denial, then by doubt, and lastly by partial accept- ance.” I have always been a be- liever in the sea-serpent of Capt. McQuhae, of the Dcedalus. I was a very young lad when his report of the 36 ILLUSIONS OF THE SENSES : strange encounter first appeared ; but it seemed to me then, and it seems to me still, that the sea captain had much the best of the discussion with the representatives of science. There was that cautious naturalist and palaeon- tologist, Richard Owen, so anxious to disprove the sea-serpent that he pict- ured to himself the captain and officers of a British frigate frightened out of their wits, and out of one at least of their senses, by the sight of a sea-ele- phant (as he tried to make out) rather far away from its native abode, and urging its course as fast as possible homeward. Captain McQuhae, in a report to the Admiralty, says that he and his officers saw a long-necked sea monster traveling swiftly in the teeth of a ten-knot breeze on the surface of the sea, so quickly that he could see the waves frothing against the creature’s chest. It passed so near that he could have distinctly seen the features of a man at the distance. He and his officers had a good view of the creature. (For a wonder, they were not possessed by the customary desire to shoot it, a desire which speaks as honorably of the human race as the saying of the North Country miner immortalized by Leech, who, seeing a stranger, thought it due welcome to “ ’eave 5 arf a brick at un.”) They rejected the sea-elephant with derision, as en- tirely inconsistent with what they had clearly seen ; while the idea of their being frightened — well, Americans in old times tackled a few of our British frigates with greater or less success, but they did not find our seamen quite so timorous as to be likely to tremble in their shoes at the sight even of an extra large sea-elephant. Yet Prof. Owen persisted in his belief that the Dcedalus sea-serpent story was not worthier of credence than a story about ghosts. That particular ghost he thought he had laid. Since then all sorts of explanations of sea-serpent stories have been ad- vanced. Because one captain has mistaken a lot of floating sea-wreck .half a mile away for a sea monster, therefore the story of a sea creature seen swiftly advancing against wind and sea, at a distance of less than 200 yards, meant nothing^more than mis- understood sea-weed. Another mis- takes a flight of birds in the distance or a shoal of porpoises, or even a range of hills beyond the horizon, for some sea-sepentine monster, and forthwith other accounts, however manifestly inconsistent with such explanations, are regarded as ex- plained away. Then, worst of all, some idiot invents a sea-serpent to beguile his time and find occupation for his shallow pate, and so soon as the story is shown to be only a story, men of sense and standing, as incapa- ble of the idiocy of inventing sea- monsters as I am of inventing a planet, are supposed to have amused their leisure by sending grave reports of non-existent sea-monsters to men under whom they (the seamen, not the sea-monsters) held office, or by taking oath before magistrates that they had seen sea creatures which they had invented, and by parallel absurdities. All this has been done m the case of the sea-serpent, as something akin to it was long since done in the case of the cameleopard, and later in the case of the gorilla. Much earlier Herodotus had been called the Father of Lies instead of the Father of His- tory, because of wonders related by him which have since been shown to be facts. The poor (in intellect and veracity) are always with us ; and they can never admit that anything exists outside what they know, or understand how any traveler in little known regions can fail to lie lustily when he comes home again. Among the creatures thus specially ridiculed the monster earth-worm described by Rapp, some forty years ago, was spe- cially ridiculed, and those who believed in it, or declined utterly to reject it, were sneered at just as those who recognize the reasonableness of the sea-serpent are laughed at now. Rapp said he had seen in South Africa a monstrous earth-worm, sev- AND OTHER ESSAYS. 37 eral feet in length. One of these he described as 6 ft. 2 in. long, and pro- portionately thick. The measurement was regarded as not worthier of credence than Gulliver’s precise state- ments of the height of Lilliputian and Brobdingnagian animals. The ab- surdity and impossibility of the thing was abundantly proved. A worm of the ordinary kind averages, let us say, 6 in. in length. Here, if this lying traveler was to be believed, was an animal more than twelve times as long, and therefore some 1,800 times as large. Now, the ordinary boa- constrictor is about eighteen feet long. Multiply his length by twelve, and we get a serpent of 216 feet in length. Credat judceus , &c. Rapp was demonstrably a vendor of lies — so, at least, said the young buccaneers of the press. Well, there is now in the Zoological Gardens in London a living specimen of the species de- scribed by Rapp. It is not one of the largest. Indeed, these creatures are hard to catch and keep alive ; and probably the biggest are the most difficult to secure. They are de- scribed as “ fairly abundant in the neighborhood of Port Elizabeth and other parts of Cape Colony,” but they keep out of sight unless heavy rains drive them out of their holes, when hundreds of them can be seen crawl- ing about, but they usually perish soon after thus visiting the surface. The specimen at the Zoological Gar- dens is about five feet long, however, so that it is quite a good-sized worm. Here, then, is a case where a creature, the description of which excited as much ridicule as that of the sea-ser- pent, is found not only to exist in large numbers, but to be amenable to the customary treatment extended by our kindly race to the inferior races : we have captured a specimen and keep it on show. Yet those who formerly laughed at the earth-worm laugh now about the fancied sea-serpent. They laugh so consumedly, and make so much noise over it — the laughter of such folk being “as the crackling of thorns under a pot ” — that, as my friend Mr. W. Mattieu Williams points out, and as I can confirm, “ much valuable evidence concerning the sea-serpent is suppressed by the flippant sneering of the class of writers who require no other qualification than ignorance of the subject on which they write. Scores, perhaps hundreds, of trust- worthy mariners of all ranks, in both the naval and mercantile services, have seen what they believe to be such a creature, but they refuse to publish any account of their observa- tions, knowing they will be insulted, and publicly gibbeted as fools and liars if they do.” The foolish laughed in the same way over the kraken, as you point out, and the monster they rejected as impossible has been killed and meas- ured. Whether the sea-serpent, or any creature whose prey is chiefly sought at a considerable distance below the surface, will ever be cap- tured or killed is very doubtful. But their existence ought never to have been regarded as doubtful after the evidence gathered in Massachusetts in 1817, and the report of the captain of the Dcedalus. There are probably several varieties of sea-creatures which look like serpents, and among these varieties some may quite proba- bly be really serpentine. But some of the supposed sea-serpents must have really propelled themselves otherwise than as serpentine sea- creatures do. For they moved rap- idly along the surface without percep- tible undulations, and nothing but concealed paddles could have urged them on in this way. In my article on “ Strange Sea- Creatures,” which appeared eleven years ago in The Gentleinciri s Magazi?ie, several singu- lar inhabitants of the sea — and in particular a monstrous skate seen in the East Indies — are described, and evidence given to show that even among comparatively familiar species, new varieties are from time to time being discovered. Thus, though no sea-serpent so large as the Sea Orm or Sea Worm, described by Bishop 38 ILLUSIONS OF THE SENSES: Pontoppidan as six hundred feet in length, have as yet been seen, it does not follow that none such exist, albeit, I cannot doubt that the good Bishop’s accounts are very largely exaggerated. He was not quite so foolish as the modern critic, who, though he per- haps has never left his native town, undertakes to contradict men who describe what they have seen. But I fear he erred as far in the opposite direction. The boa-constrictor and the condor have been described in such terms by comparatively modern travelers (as Humboldt has shown) as would suggest creatures akin to the serpent which went for Sindbad, and the roc which also adorns Sind- bad’s narrative and appears elsewhere in tales of the East. But to exagger- ate is one thing, to invent is another. The man who is foolish enough to lie about his traveling experiences is not capable of inventing a new animal worth five minutes’ consideration ; but, on the other hand, the man who, being sensible, is honest and truthful, is yet very apt to err in the way of unintentional exaggeration. I think poor Capt. Drevar’s narrative of a long-necked sea monster which cap- tured in its folds and took down a sperm whale was a little exaggerated, though he and his mates swore to the truth of the story before a magistrate, and he himself was most unfairly punished by his employers for telling what he had seen — he was, in fact, ruined for life. (“I would not tell about it,” said an old salt to Capt. Drevar, “ if I saw five hundred sea- sarpints.”) But I no more believed that these men would have invented such an animal if they could, or could have invented it if they would, than I believe that an utterly ignorant man could have devised the famous Lunar Hoax — the clever story respecting a powerful telescope showing living creatures in the moon. Yet that story did not, as was alleged, take in Arago ; no one acquainted with opti- cal laws could have been deceived by it for an instant. To imagine that sailors could accomplish the far more difficult feat of inventing a new kind of animal, without immediately expos- ing their ignorance to every one acquainted with the laws of compara- tive anatomy, is to imagine the impos- sible. THE ORIGIN OF COMETS. Encke’s comet has returned to our neighborhood, and is now (February, 1885) under observation. Yet to all ordinary appearance our skies are un- changed. Those who associate the re- turn of a comet with the appearance of an awe-inspiring object, with long, sword-like tail brandished athwart the heavens, like those comets which have in past and recent ages terrified the nations, are disappointed when they hear that the comet of which the papers speak, and which Professor Young re-discovered a few days ago, and our telescopists are carefully ob- serving, is one which cannot even be seen without telescopic aid. Yet to the student of astronomy the tri- umph is greater when one small comet is caught in the toils of mathe- matical analysis, and detected as it advances along its return track, than when the most glorious new comet blazes in our skies, and by rapid changes of position and of form at- tracts the admiring attention of all men. I propose to make the return of Encke’s comet — the comet of shortest period known — the text for some re- marks about the theories of comets more or less in vogue among astron- omers, and especially those theories which relate to the origin of these bodies, or at least their introduction into our solar system. It may be remembered that at the last meeting of the American Associ- ation for the Advancement of Science, Professor Young touched on what he called the received theory of the ori- gin of comets, and what he admitted was a valid objection of mine against that theory. AND OTHER ESSAYS. 39 What Professor Young calls the re- ceived theory is, I take it, neither a theory nor generally received — it only comes in company with a received theory. Schiaparelli, the ingenious chief of the observatory of Milan, threw out, in 1866, the idea that the bodies which produce the star-showers of Aug. 10 and 11 (the Tears of St. Laivrence they were fancifully called in old times) are attendants on the Comet of 1862. When he had shown, which was an easy thing to do, that the apparent movements of those falling stars on the stellar heav- ens accord with the theory that they are moving in parallel tracks, touch- ing (at any rate) the orbit of that com- et at the place where it crosses the earth’s track (a point passed by the earth on or about Aug. 10-11), it was felt that he had done something in support of his hypothesis. But when Professor Adams had shown, which was by no means an easy thing to do, that the bodies producing the display of November meteors travel in the very track of the comet of 1866 (known as Tempel’s), astronomers saw that Schiaparelli’s case was proved. It passed thenceforward from the condition of a mere specula- tion to that of a received theory. This is the received theory about comets and meteors which every as- tronomer who can understand the evi- dence accepts without hesitation — Me- teors are bodies which travel on the tracks of comets. More than that has not yet been shown, and more than that is certainly not received by as- tronomers as a body. But Schiaparelli suggested more. He threw out a speculation concern- ing the origin of comets based on his established theory as to the connec- tion between comets and meteors. This speculation would explain, if es- tablished, the way in which meteors travel on the tracks of comets. It ran as follows : — Amidst the interstel- lar depths are flights and clouds of meteoric bodies, which from time to time are drawn out of those depths by the attractive influence of the sun. Were the sun alone in the universe they would be drawn toward him, sweep around him in greater or less proximity to his surface according to the course on which they chanced to be drawn, and so pass out again to the depths from which they came. But as the sun has a family of attend- ant planets and some of these are somewhat stalwart fellows, many of the meteor-flights drawn sunwards are so acted upon by the disturbing influence of Jupiter, or Saturn, or Uranus, or Neptune, or mayhap some outer and still unknown members of the family of giant planets, that they are deflected from their course and thenceforward travel on a closed path — elliptic, of course — around the sun. The place where the deflection took place remains thenceforward a part of the comet’s path, which therefore seems to associate itself with the path of the deflecting planet, in such sort that, though the sun is the chief ruler of the comet, the planet which intro- duced it into the solar system retains a sort of secondary influence over the comet’s movements. Should the comet chance to revisit the scene of deflection when the planet is passing the same place, potent disturbing in- fluences may be exerted on the comet, which may even send it wandering yet once more into the domain of in- terstellar space whence, according to this speculation, it was drawn. Now, I pointed out more than eleven years since that this part of Schiaparelli’s imaginings is entirely without foundation in known facts. We may guess that the interstellar depths are a sort of breeding-place for comets and meteor systems, — though why they should be so not even Schiaparelli has ventured a sug- gestion. We may imagine that in the interstellar depths there still remain the scattered fragments of such ma- terials as, when gathered in, had formed our solar system with all its worlds ; though why any such frag- ments should remain there , instead of responding to the influences which brought their fellows to the neighbor. 40 ILLUSIONS OF THE SENSES : hood of our system, would remain still unexplained. Only five or six millions of years would be required to draw in matter to the sun from half the distance separating him from his nearest neighbor among the stars, and our earth’s crust tells us of tens of millions of years already passed since the sun had gathered in his mass so as to shine as a sun upon the earth. But we may concede for a moment the possibility of the wander- ing meteor flights of interstellar space imagined by Schiaparelli. How are we thereby helped to an interpreta- tion of the origin of meteor systems now in attendance on the sun? Not a whit, seeing that we have only suc- ceeded in replacing one difficulty by another still greater. If we suppose the meteor streams to have come into the interstellar depths from beyond, that is from the domain of some star, we have re- moved our difficulty only a step, and not a step bringing us any nearer a solution. That other star is a sun like ours, and if a meteor system came from it to us, we have the same difficulty in understanding how the meteor system came to be in the neighborhood of that sun as we have in understanding it as belonging for a while to our own sun. One may compare this attempt at a solution of a really serious difficulty to Sir William Thompson’s well-known at- tempt to explain the origin of life in our planet. This he did by surmis- ing that millions of years ago another planet was the abode of life, that that planet came unfortunately into collis- ion with another or burst, and that some of the fragments after flitting from sun to sun a few times chanced in their passage through our solar system to encounter our earth, where, falling on good soil, the germs brought forth abundant life : development did all the rest. That planet may have inherited the germs of life from an- other which had burst or collided a few millions of years before, and so on ; we may in fact adopt a theory of planetary life akin to the theory of in- dividual life — omne vivum ex ovo— and say every live planet received its life from a planet which was full of life, but burst up. Schiaparelli’s cometic speculation asserts in like manner that every meteoric system or comet now associated with the sun came here athwart the star depths from another sun with which, millions of years ago, it was in like manner as* sociated. All this, however, is not scientific theorizing but speculation. There is no evidence in support of Schiapa- relli’s supposition. If it were estab- lished we should be as far off as ever from knowing the real origin of comets. But lastly, there happens to be demonstrative evidence against the theory : — Take the November meteors, whose path crosses that of Uranus so close- ly as to show that Uranus was the planet which introduced this partic- ular meteor system, if the theory has in it any truth at all. The Novem- ber meteors, and of course Tempel’s comet, in whose track they travel, cross the path of Uranus now with a velocity of 1% miles per second. A meteor coming to our sun from inter- stellar space would cross the track of Uranus, if it chanced to come in the right direction, with a velocity of nearly 6 miles per second. Uranus, then, to do what certainly has been done if Schiaparelli’s idea is right, must have abstracted a velocity of 4 y2 miles per second from every one of a flight of meteors traveling past it. Now it may be barely possible (I doubt if it is, but the calculations necessary are too abstruse to be en- tered on save for a very special pur- pose) for Uranus to abstract so great a velocity from a body traveling past him. If Uranus drew a body to him- self from interstellar space, no other member of the solar system, not even the sun, interfering, he could give to the approaching body a velocity of 1^/2 miles per second ; but he could not give any thing like this velocity to a body rushing along by him with sun-imparted velocities, and therefore AND OTHER ESSAYS. 41 exposed for a shorter time to his in- fluence. Moreover, in any passage by Uranus some part of the velocity abstracted or added in one part of the passage would be restored or taken aWay again in the remaining part. At the utmost, Uranus might abstract from a single meteor some 4 miles per second of its velocity of 6 miles per second. But Uranus could not possibly produce the same effects on the members of a flight of meteors, however closely we may con- ceive them to be set. Some would have their velocities much less effec- tively reduced. And the deflections of direction would be also altogether different. Nothing could save a me- teor-flight from being dispersed along widely divergent paths if it came near enough to Uranus to have the motion of any of its members sufficiently af- fected to make them travel hencefor- ward in such an orbit as is actually pursued by the November meteors, which all travel along the same path. This which is true of one meteor system or comet is true of all. Un- der no conceivable conditions could a meteor-flight be introduced into our solar system as Schiaparelli imagined. Hence a different theory of the ori- gin of the families of comets asso- ciated with the giant planets must be adopted. We must in some way ad- mit that every comet was once in the neighborhood of one of the giant planets in the form of a closely-set flight of meteors. This being so, the natural explanation is that each comet started from a planet, — by a process akin to volcanic ejection, or in some such way. Now, on the one hand the sun does eject bodies from his in- terior, in mighty eruptions which have been actually watched ; and the plan- ets when in the sunlike state may well be believed to have done like- wise ; and on the other hand there is evidence to show that even our small earth once possessed the power of ejecting meteoric bodies from her in- terior (Prof. Ball considers that some meteor-flights still in existence were earth-born). On the whole, then, the view seems suggested that comets like Encke’s were ejected from the interior of the planet on which they are still found to be dependent. CONTENTS. Illusions of the Senses Animals of the Present and the Past Life in Other Worlds Earthquakes Our Dual Brain A New Star in a Star Cloud Monster Sea-Serpents The Origin of Comets PAGE? I II 13 27 3 2 35 3 & CATALOGUE OF THE HUMBOLDT LIBRARY. N. B. The price of each number is 15 cents, except as otherwise stated. The Catalogue price includes postage. The Library is published 1 monthly. Price to subscribers $1.50 per pear, or 12 numbers. Any number in the catalogue sent post-free on receipt of the price. Fractional parts of a dollar may be sent in the form of postage stamps. J. FITZ&Ef&ALD, PUBLI8MER, 108 Chambers Street, Ne w 'York. No. 1. higlit Science for Leisure Hours : A series of Familiar Essays on Scien- tific Subjects. By Richard A. Proctor, F.R.A.S. Contents (in part) The Earth a Magnet ; the Secret of the North Pole ; Our Chief Timepiece Losing Time ; Tornadoes ; Influence of Marriage on the Death Rate ; Squaring the Circle ; the Use- fulness of Earthquakes ; the Forcing Power of Rain, etc., etc. No. 2. Tlie Forms of Water in Clouds and Rivers, Ice and Glaciers. By John Tyndall, LL.D., F.R.S. (illustrated). Contents (in part) : — Oceanic Distillation ; Archi- tecture of Snow ; The Motion of Glaciers ; Icicles ; Erratic Blocks; Tropical Rains; Atomic Poles; Birth of a Crevasse ; Moraine Ridges, etc., etc., etc. No. 3. Physics and Politics:— An Appli- cation of the Principles of Natural Selection and Heredity to Political Society. By Walter Bage- hot, Author of “ The English Constitution,” etc. Contents . — The Preliminary Age ; the Use of Conflict ; Nation Making ; the Age of Discussion ; Verifiable Progress Politically Considered. No. 4. Evidence as to Man’s Place in Nature. By Thomas Huxley, F.R.S. (illus- trated). Contents The Natural History of the Manlike Apes ; The Relations of Man to the Lower Ani- mals ; Fossil Remains of Man. No. 5. Education: Intellectual, Moral and Physical. By Herbert Spencer. Contents What Knowledge is of Most Worth ? Intellectual Education ; Moral Education; Physi- cal Education. No. 6. Town Geology. By the Rev. Charles Kingsley, F.R.S., Canon of Chester. Contents: — The Soil of the Field; the Pebbles in the Street ; the Stones in the Wall ; the Coal in the Fire ; the Lime in the Mortar ; the Slates on the Roof. No. 7. The Conservation of Energy. By Balfour Stewart, F.R.S. (illustrated). Contents : — What is Energy ? Mechanical En- ergy and its Change into Heat ; The Forces and Energies of Nature; Transmutations of Energy; the Dissipation of Energy ; the Position of Life ; Correlation of Nervous and Mental Forces. No. 8. Tlie Study of Languages brought back to its true Principles. By C. Marcel. Contents : — Subdivision and Order of Study ; the Art of Reading ; the Art of Hearing ; the Art of Speaking ; the Art of Writing ; Mental Culture ; Routine. No. 9. Tlie Data of Etliics. By Herbert Spencer. Contents : — Conduct in General ; Evolution of Conduct; Good and Bad Conduct; Ways of Judg- i ing Conduct ; The Physical View ; The Biological View ; the Psychological View ; the Sociological View ; Criticisms and Explanations ; Relativity of Pains and Pleasures ; Egoism vs. Altruism ; Al- truism vs. Egoism; Trial and Compromise; Con- ciliation ; Absolute Ethics and Relative Ethics ; the Scope of Ethics. No. 10. Tlie Theory of Sound in its Rela- tion to Music. By Prof. Pietro Blaserna, of the Royal University of Rome (illustrated). Contents (in part) ; — Periodic Movements, vibra- tion ; Transmission of- Sound; Characteristics of Sound, and difference between musical sound and noise ; Discords ; Quality or timbre of musical sounds ; Italian and German music, etc., etc. Nos. 11 and 12. Tlie Naturalist on tlie Stiver Amazons :— A Record of Adventures, Habits of Animals, Sketches of Brazilian and Indian Life, and Aspects of Nature under the. Equator, during eleven years of Travel. By Henry Walter Bates, F.R.S. *** One of the most charming books of travel in our language. No. 13. Mind and Body: The Theories of their Relation. By Alexander Bain, LL.D., Professor of Logic in the University of Aber* deen. Contents : — The Question Stated ; Connection of Mind and Body ; the Connection viewed as corre- spondence or concomitant variation ; General Laws of Alliance of Mind and Body: the Feelings and will ; the Intellect ; How are Mind and Body United ? History of the Theories of the Soul. No. 14. Tlie Wonders of the Heavens. By Camille Flammarion (illustrated). Contents (in part) The Heavens ; the Milky Way ; Double, Multiple and Colored Suns ; the Planets ; the Earth ; Plurality of Inhabited Worlds * Infinite Space; Constellations; The Sun ; Comets; the Moon, etc., etc. No. 15. longevity : the Means of Prolong- ing Life after the Middle Age. By John Gard- ner, M. D. Contents (in part) : — Is the Duration of Life in any way within our power? Physiology of Ad- vanced Age ; Heredity ; Established Facts regard- ing Longevity, etc., etc. No. 16. On the Origin of Species ; or the Causes of the Phenomena of Organic Nature : A Course of Six Lectures. By Thomas H. Hux- ley, F.R.S. Contents :— Present Condition of Organic Nature ; Past Condition of Organic Nature ; Origination of Organic Beings ; Perpetuation of Living Beings ; Conditions of Existence ; A Critical Examination of Mr. Darwin’s Great Work, No. 17. Progress: its haw and Cause; with other disquisitions. By Herbert Spencer. Contents : — Progress ; the Physiology of Laugh- ter : Origin and Functions of Music ; the Develop- ment Hypothesis ; the Social Organism ; the Use of Anthropomorphism. No. 18. Lessons in Electricity. By John Tyndall, F.R.S. (illustrated). Contents (in part) : — The Art of Experiment ; Electric Induction ; Lichtenberg’s Figures ; Elec- trics and Non-Electrics ; the Leyden Jar ; Physio- logical Effect of the Electric Discharge ; Atmos- pheric Electricity, etc., etc. No. 19. Familiar Essays on Scientific Subjects. By Richard A. Proctor, F.R.A.S. Contents Oxygen in the Sun ; Sun-spot, Storm and Famine ; New ways of Measuring the Sun’s Distance ; Drifting Light-waves ; The new Star which faded into Star-mist ; Star-grouping. No. 20. The Romance of Astronomy. By R. Kalley Miller, M.A. Contents ' The Planets ; Astrology ; The Moon ; the Sun ; the Comets ; Laplace’s Nebular Hypoth- esis ; the Stars ; the Nebulae ; Appendix. No. 21. On the Physical Basis of Life. With other Essays. By Thomas H. Hux- ley, F.R.S. Contents : — Physical Basis of Life ; Scientific Aspects of Positivism ; A Piece of Chalk ; Geolog- ical Contemporaneity ; A Liberal Education and where to find it. No. 22. Seeing and Thinking. By Prof. William Kingdon Clifford, F.R.S. (illustrated). Contents : — The Eye and the Brain ; the Eye and Seeing ; the Brain and Thinking ; On Boundaries in General. No. 23. Scientific Sophisms:— A Review of Current Theories concerning Atoms, Apes and Men. By Samuel Wainright, D.D. Contents .-—The Right of Search ; Evolution : A Puerile Hypothesis ; Scientific Levity ; a House of Cards ; Sophisms ; Protoplasm ; the Three Begin- nings ; the Three Barriers ; Atoms ; Apes ; Men ; Anima Mundi. No. 24. Popular Scientific ILectures. By Prof. H. Helmholtz (illustrated). Contents : — The Relation of Optics to Painting, i. Form. 2 . Shade. 3 . Color. 4 . Harmony of Color ; the Origin of the Planetary System ; Thought in Medicine ; Academic Freedom in Ger- man Universities. No. 25. The Origin of Nations Com- prising two divisions, viz.: — “ Early Civiliza- tions,” and “Ethnic Affinities.” By George Rawlinson, M.A., Camden Professor of Ancient History in Oxford University, England. Contents : — Early Civilizations Introduction ; Antiquity of Civilization in England ; Antiquity of Civilization at Babylon : Phoenician Civilization ; Civilizations of Phrygia, Lydia, the Troas, Assyria, Media, India, etc.; Civilization of 'the British Celts ; Civilization of the Etruscans ; Results of jthe In- quiry. Ethnic Affinities ; — Chief Japhetic Races ; Subdivisions of the Japhetic Races ; Chief Hametic Races: Subdivisions of Cush ; Subdivisions of Miz- raim and Canaan ; the Semitic Races ; Subdivis- ions of the Semitic Races. No. 26. The Evolutionist at Earge. By Grant Allen. Contents (in part) : — Microscopic Brains ; Slugs and Snails ; Butterfly Psychology ; In Summer Fields; Speckled Trout; Origin of Walnuts ; Dogs and Masters, etc., etc. No. 27. The History of Eandholding in England. By Joseph Fisher, F.R.H.S. Contents (in part) : — The Aborigines ; the Scan- dinavians ; the Plantagenets ; the Stuarts ; the Ro- mans ; the Normans; the Tudors; the House of Brunswick ; Land and Labor, etc., etc. No. 28. Fashion in Deformity, as Illus- trated in the Customs of Barbarous and Civil- ized Races. By William Henry Flower, F.R.S. (illustrated). To which is added : — Manners and Fashion. By Herbert Spencer. Contents (in part): — Fashions in Coiffure ; Tat- tooing; Deforming the Teeth ; Deforming the Feet ; Eradicating the Eyebrows ; Ornaments for the Nose, Ears, Lips ; Compressing the Skull ; Effects of Tight Lacing, etc., etc. No. 29. Facts and Fictions of Zoology. By Andrew Wilson, Ph.D. (illustrated). Contents Zoological Myths ; the Sea Serpents of Science ; Some Animal Architects ; Parasites and Their Development ; What I saw in an Ant’s Nest. Nos. 30 and 31. On the Study o£ Words. By Richard Chenevix Trench, D.D. Contents :— Introduction ; the Poetry in Words ; the Morality in Words ; the History in Words ; the Rise of New Words ; the Distinction of Words ; the Schoolmaster’s use of Words. No. 32. Hereditary Traits, and other Essays. By Richard A. Proctor, F.R.A.S. Contents :— Hereditary Traits ; Artificial Som- nambulism ; Bodily Illness as a Mental Stimulant ; Dual Consciousness. No. 33. Vignettes from Nature. By Grant Allen. Contents (in part) :— Fallow Deer ; the Heron’s Haunt ; Wild Thyme ; the Fall of the Leaf ; the Hedgehog’s Hole ; Seaside Weeds ; the Donkey’s Ancestors. No. 34. Tlie Philosophy of Style. By Herbert Spencer. To which is added :— The Mother Tongue. By Alexander Bain, LL.D. Contents: — The Principle of Economy applied to words; Effect of Figurative Language Ex- plained ; Arrangement of Minor Images in build- ing up a thought ; The Superiority of Poetry to Prose explained ; Causes of Force in Language which depend upon Economy of the Mental Sensi- bilities ; the Mother Tongue. No. 35. Oriental Religions. Edited by Rev. John Caird, D.D., President of the Uni- versity of Glasgow. Contents : — Brahmanism ; Buddhism ; Confu- cianism ; Zoroaster and the Zend Avesta. No. 36. Iiectures on Evolution, with a« Appendix on the Study of Riology. By Thomas H. Huxley, F.R.S. (illustrated). Contents : — The Three Hypotheses respecting the History of Nature ; the Hypothesis of Evolu- tion — the Neutral and Favorable Evidence ; the Demonstrative Evidence of Evolution ; the Study of Biology. No. 37. Six Lectures on Light. By John Tyndall, F.R.S. (illustrated). Contents : — Introductory ; Origin of Physical Theories ; Relation of Theories to Experience ; Chromatic Phenomena produced by Crystals ; Range of Vision and Range of Radiation ; Spec- trum Analysis. Nos. 38 and 39. Geological Sketches at Home and Abroad \ in two Parts, each complete in itself. By Archibald Geikie, F.R.S. Contents : Part I : — My first Geological Excur- sion ; “ The Old Man of Hoy ” ; the Baron’s Stone of Killochan ; the Colliers of Carrick ; Among the Volcanoes of Central France ; the Old Glaciers of Norway and Scotland ; Rock-Weathering meas- ured by Decay of Tombstones. Part II : A Frag- ment of Primeval Europe ; In Wyoming ; The Geysers of the Yellowstone ; the Lava fields of Northwestern Europe ; the Scottish School of Geology ; Geographical Evolution ; the Geologi- cal influences which have affected the course of British History. No. 40. The Scientific Evidence of Or- ganic Evolution. By George J. Romanes, F.R.S. Contents (in part) : — The Argument from Classi- fication — from Morphology or Structure — from Geology— from Geographical Distribution— from Embryology, etc., etc. No. 41. Current Discussions in Sci- ence. By W. M. Williams, F.C.S. Contents (in part) : The Fuel of the Sun ; Ori- gin of Lunar Volcanoes ; Aerial Exploration of the Arctic Regions ; The Air of Stove-heated Rooms, etc., etc. No. 42. History of the Science of Poli- tics. By Frederick Pollock. Contents: The Place of Politics in Human Knowledge ; The Classic Period — Pericles— Soc- rates — Plato— Aristotle, etc.; the Medieval Period — the Papacy and the Empire ; Beginning of the Modern Period — Machiavelli — Hobbes ; the Mod- ern Period — Locke — Hooker— Blackstone — Hume— Montesquieu — Burke ; the Present Century — Ben- tham — Austin — Kant — Savigny — Herbert Spencer. No. 43. Darwin and Humboldt, their Lives and Works Contains a series oS notices of Darwin, by Huxley, Romanes, Geikia, Thiselton Dyer ; also the late Prof. Agassiz’s Centennial Address on the Life and Work of Alexander von Humboldt. Nos. 44 and 45. The Dawn of History : an introduction to Pre-Historic Study. Edited by C. h. Keary, M.A., of the British Museum. In two Parts. Contents of Part I : Earliest Traces of Man ; the Second Stone Age ; the Growth of Languages ; Families of Languages ; the Nations of the Old World; Early Social Life ; the Village Community. Contents of Part II: Religion; Aryan Religion; the Other World ; Mythologies and Folk Tales ; Picture Writing ; Phonetic Writing ; Conclusion. No. 46. The Diseases of Memory. By Th. Ribot. (Translated from the French by J. Fitzgerald.) Contents Memory as a Biological Fact ; Gen- eral Amnesia ; Partial Amnesia ; Exaltation of Memory, or Hypermnesia ; Conclusion. No. 47. The Childhood of Religions. By Edward Clodd, F.R.A.S. Contents (in part) Legends of the Past about Creation ; Creation as told by Science ; Legends of the Past about Mankind ; Ancient and Modern Hindu Religions, etc., etc. No. 48. Life in Nature. By James Hinton, Author of “ Man and his Dwelling Place.” Contents (in part). — Function,* Living Forms; Is Life Universal ? Nutrition ; Nature and Man ; the Life of Man, etc., etc. No. 49. The Sun:— its Constitution; its Phe- nomena ; its Condition. By Nathan T. Carr, LL.D., Judge of the Ninth Judicial Circuit of Indiana. Contents (in part) : — The Sun’s Atmosphere ; the Chromosphere ; the Photosphere ; Production of the Sun’s Spots ; the Question of the Extinction of the Sun, etc., etc. Nos. 50 and 51. Money and the Mech- anism of Exchange. By Prof. W. Stan- ley Jevons, F.R.S. Contents (in part) : — The Functions of Money ; Early History of Money ; the Metals as Money ; Principles of Circulation ; Promissory Notes ; the Banking System ; the Clearing House ; Quantity of Money needed by a Nation, etc., etc. No. 52. The Diseases of the Will. By Th. Ribot. (Translated from the French by J. Fitzgerald.) Contents : — The Question Stated ; Impairment of the Will — Lack of Impulsion — Excess of Impul- sion ; Impairment of Voluntary attention ; Caprice ; Extinction of the Will ; Conclusion. No. 53. Animal Automatism, and Other Essays. By Prof. T. H. Huxley, F.R.S. Contents : — Animal Automatism ; Science and Culture ; Elementary Instruction in Physiology ; the Border Territory between Animals and Plants ; Universities, Actual and Ideal. No. 54. The Birth and Growth of Myth. By Edward Clodd, F.R.A.S. Contents (in part) : — Nature as viewed by Primi- tive Man ; Sun and Moon in Mythology ; the Hindu Sun and Cloud Myth ; Demonology ; Beast Fables ; Totemism, etc., etc. No. 55. The Scientific Basis of Morals, and Other Essays. By William Kingdon Clifford, F.R.S. Contents Scientific Basis of Morals ; Right and Wrong; the Ethics of Belief; the Ethics of Re- ligion. Nos. 56 and 57. Illusions: A Psy- chological Study. By James Sully. Contents : — The Study of Illusion ; Classification of Illusions ; Illusions of Perception ; Dreams ; Illusions of Introspection ; Other Quasi-Presenta- tive Illusions ; Illusions of Memory ; Illusions of Belief. Nos. 58 and 59 (two double numbers, 30 cents each). The Origin of Species. By Charles Darwin. *** This is Darwin’s famous work complete, with index and glossary. No. 60. The Childhood of the World. By Edward Clodd, F.R.A.S. Contents (in part) Man’s First Wants, Man’s First Tools, Fire, Dwellings, Use of Metals ; Lan- guage, Writing, Counting, Myths about Sun and Moon, Stars, Eclipses ; Ideas about the Soul, Be- lief in Witchcraft, Fetichism, Idolatry, etc., etc. No. 61. Miscellaneous Essays. By Rich- ard A. Proctor. Contents: — Strange Coincidences; Coincidences and Superstitions ; Gambling Superstitions ; Learning Languages ; Strange Sea-Creatures ; the Origin of Whales ; Prayer and Weather. No. 62 (Double number, 30 cents). The Re- ligions of the Ancient World. Contents : — Religions of the Ancient Egyptians, ancient Iranians, Assyrians, Babylonians, ancient Sanskritic Indians, Phoenicians, Carthaginians, Etruscans, ancient Greeks and ancient Romans. No. 63. Progressive Morality. By Thomas Fowler, F.S.A., President of Corpus Christi College, Oxford. Contents: — The Sanctions of Conduct; the Moral Sanction, or Moral Sentiment ; Analysis and Formation of the Moral Sentiment ; the Moral Test ; Examples of the practical applications oi the Moral Test. No. 64. The Distribution of Life. By Alferd Russel Wallace and W. T. Thiselton Dyer. Contents (in part) :— Geographical Distributfbn of Land Animals ; Distribution of Marine Ani- mals ; Relations of Marine with Terrestrial Zoolog- ical Regions; Distribution of Vegetable Life; Northern, Southern, Tropical Flora, etc., etc. No. 65. Conditions ct Mental Devel- opment, and Other Essays. By William Kingdon Clifford, F.R.S. Contents :— Conditions of Mental Development ; Aims and Instruments of Scientific Thought ; Atoms ; The First and the Last Catastrophe. No. 66. Technical Education, and other Essays. By Thomas H. Huxley, F.R.S. Contents: — Technical Education; The Connec- tion of the Biological Sciences with Medicine; Joseph Priestley ; On Sensation and the Unity of Structure of the Sensiferous Organs ; On Certain Errors respecting the Structure of the Heart at- tributed to Aristotle. No. 67. The Black Death $ An account of the Great Pestilence of the 14 th Century. By J. F. C. Hecker, M.D. Contents : — General Observations ; the Disease ; Causes — Spread, Mortality ; Moral Effects ; Physi- cians ; Appendix. No. 68 (Special Number, 10 cents). Three Essays, viz.: Laws, and the Order of their Discovery ; Origin of Animal Worship ; Politi- cal Fetichism. By Herbert Spencer. No. 69 (Double Number, 30 cents). Fetich- ism : A Contribution to Anthropology and the History of Religion. By Fritz Schultze, Ph.D. Translated from the German by J. Fitzgerald, M.A. Contents ;— The Mind of the Savage ; Relation between the Savage Mind and its Object ; Fetich- ism as a Religion ; Various Objects of Fetich Wor- ship;— The Highest Grade of Fetichism; Aim of Fetichism. Catalogue of the Humboldt Library (CONTINUED). No. 70. Essays, Speculative and Practical. By Herbert Spencer. Contents: — Specialized Administration; “The Collective Wisdom;” Morals and Moral Sentiments; Reasons for Dissenting from the Phi- losophy of Comte; What is Electricity? No. 71. Anthropology. By Daniel Wilson, LL. D. Contents: — Scope of the Science; Man’s Place in Nature; Origin of Man; Races of Mankind; Antiquity of Man; Language; Development of Civilization. No. 72. The Dancing Mania of the Middle Ages. By J. F. C. Hecker, M. D. Contents (in part): — The Dancing Mania in Germany and the Nether- lands; The Dancing Mania in Italy; The Dancing Mania in Abyssinia. No. 73. Evolution in History, Language, and Science. Lectures delivered at the London Crystal Palace School of Art>, Science, and Literature. Contents: — The Principle of Causal Evolution; Scientific Study of Geography; Hereditary Tendencies; Vicissitudes of the English Lan- guage. Nos. 74, 75, 76, 77. The Descent of Man, and Se- lection in Relation to Sex. By Charles Darwin. *** Price, Parts 74, 75, 76, fifteen cents each; No. 77 (double num- ber), thirty cents; the entire work, seventy-five cents. No. 78. Historical Sketch of the Distribution of Land in England. By Prof. Wm. Lloyd Birkbeck, Cam- bridge University. (Ready Feb. 25, 1886.) Valuable Books For Sale by the Publisher of THE HUMBOLDT LIBRARY. DICK'S containing 6,422 practical receipts, embracing valuable information in the Arts, Professions, Trades, Manufactures, including Medicine, Phar- macy, and Domestic Economy. Profusely illustrated; 607 Royal Octavo pages. Price, Cloth, $5.00; Sheep, $6.00. DICAN'S MASONIC RITUAL AND MONITOR. or Guide to the three Symbolic Degrees of the Ancient York Kite, En- tered Apprentice, Fellow Craft, Master Mason, etc. Price, Cloth, $2.50; Leather Tucks (pocket-book style). Gilt edges, $3.00. Allyn’s Ritual of Freemasonry, containing a Complete Key to the Several Degrees, Illustrated with Thirty Copper-plate Engravings. To which is added a Key to the Phi Beta Kappa, Orange, and Odd Fellows’ Societies. Price, Cloth, $5.00. Lester’s “Look to the East,” containing the Complete Work of the Entered Apprentice, Fellow Craft, and Master Mason’s Degrees, with the Ceremonies, Lectures, etc. Price, Cloth, $2.00; Leather Tucks (pocket-book style), Gilt Edges, $2.50. LANDER’S Revised Work on Odd-Fellowship. Price, Paper, 25 cents. The above works sent, post free, on receipt of Price. J. FITZGERALD, 108 Chambers Street, New York. THE CHANDOS CLASSICS OF GENERAL LITERATURE. Bound in cloth, gilt, only 80 cents per vol. Sent to any address post free, on receipt of the price by J. FITZGERALD, 108 Chambers Street, N. Y. ' 10 , 11 . 12 , 13. 14. 15 . 16. 18, 19. 20 . 21 . 22 . 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 45. 46, 47. 48, Shakspeare (Complete Works of). Byron. Scott. Arabian NIglits (The) Entertain- ments. A new edition, revised for Home Reading. By Geo. Fyler Townsend, M.A. Eliza Cook’s Poems. Legendary Ballads of England and Scotland. Burns. Johnson’s Lives of the most Emi- nent English Poets, with sketch of the author’s life by Sir Walter Scott. Bante (The Vision of). Translated by Rev. H. F. Cary, A.M. Moore’s Poetical Works. Dr. Syntax’s Three Tours, with Col- ored illustrations. Butler’s Hudibras. Cowper’s Poetical Works. Milton’s Poetical Works. Wordsworth’s Poetical Works. England : Its Constitutional His- tory. Edward I. to Henry VII., by Hen- ry Hallam. History of the Saracens. By Edward Gibbon and Simon Ockley. Spanish Ballads. Translated by J. G. Lockhart, and The Chronicle of the Cid, by Robt. Southey. Robinson Crusoe. Original illustra- tions by Ernest Griset. Swiss Family Robinson. Beautiful- ly and fully illustrated. Mrs. Hemans’ Poetical Works. Grimm’s Fairy Tales. Andersen’s (Hans) Fairy Tales. Lives of Eminent Novelists and Dramatists. By Sir Walter Scott. Essays on Chivalry, Romance and the Drama. By Sir Walter Scott, Shelley’s Poetical Works. Campbell’s Poetical Works. Beats’ Poetical Works. Coleridge’s Poetical Works. Pope’s Iliad of Homer. Illustrated with Flaxman’s designs. Pope’s Odyssey of Homer. Illustrat- ed with Flaxman’s designs. Hood’s Poetical Works. Representative Actors. By W. Clark Russell. - England. (Romance of History.) France. Ditto. Italy. Ditto. Spain. Ditto. India. Ditto. Romantic Tales founded on historical facts in the history of these countries. German Literature (Beauties of). Don Quixote De La Mancha (Ad- ventures of). Eastern Tales. In the vein of the Ara- bian Nights — suitable for the youug. Book of Authors. A collection of criti- cisms, personal descriptions, etc., referring to English men of literature in every age. By W. Clark Russell. Pope’s Poetical Works. Mackay’s (Charles) Poetical Works. Goldsmith’s Poems, Dramas, and the Vicar of Wakefield. The Koran-The Alkoran of Mo- hammed. Translated by George Sale. 49 0 Oxenford’s French Songs, including Costello’s Lays of the Troubadours. 50. Gil Bias (The Adventures of), with notes and illustrations. 52. Virgil (Dry den’s) (The Works of '. 53. Bunyan’s Holy Afar. Illustrated. 54. Dodd’s Beauties of Shakspeare. 55. Romance of London. Historic sketch- es, remarkable duels, notorious highway- men, rogueries, crimes and punishments, etc. By John Timbs, F.S.A. 56. Romance of London. Supernatural stories, sights and shows, strange adven- tures, and remarkable persons. By John Times, F.S.A. 57. A Century of Anecdote. A Collection of the best modern anecdotes of Men of Letters, Law and Lawyers, Eccentric Per- sons, etc. By John Timbs, F.S.A. 58. Walton and Cotton’s Angler. A new edition, with notes and illustrations. 59. Herbert’s (George) Works. In Prose and Verse. 60. Heber’s (Bishop) Poetical Works. 61 . Half-Hours with the Best Authors 62. Ditto. ** 63. Ditto. *** 64. Ditto. **** A compendium of choice Readings, show- ing style of all noted writers, prose and poetical, with brief biographical and critical notices of the authors. By Chas. Knight. Freely Illustrated, forming a treasury of literature for all readers. 65. Bunyan’s Pilgrim’s Progress. A clear and large type edition, with notes and illustrations. 66. Fugitive Poetry of the Last Three Centuries. A valuable collection of an- onymous poetry, sacred and secular, and Translations gathered from many sources. Compiled and edited by J. C. Hutchieson. 67. Pepys’ Diary. Edited by Richard Lord Brabrooke. 68. Evelyn’s Diary. Edited by William Bray, Esq. 69. Townsend’s Every-Day Book of Modern Literature.* 70. Townsend’s Every-Day Book of Modern Literature.** A series of short readings from the best authors. 71. Montgomery (James) (Poems of. 72. Spenser’s Faery Queen. A version of the great Elizabethan Poet's Masterpiece in modern English. With Memoir, notes and glossary. 73. Natural History of Selborne (The) and Naturalist’s Calendar. By Rev. Gilbert White, A.M. Beautifully and fully illustrated. 74. Keble’s Christian Year. 75. Lamb’s (Charles) Poems and Es- says. With choice illustrations, head and tail pieces, etc. 76. Roseoe’s Italian Novelists. 77. Roscoe’s German Novelists. 78. Roscoe’s Spanish Novelists. Choice stories and selections from the great novelists of these countries, translated with critical and biographical notices by Thomas Roscoe. *** And 20 other Volumes. Complete Catalogue sent free to any address. V Humboldt Library Catalogue. Price : Single Number ........ 15 Cents . Per Year ( 12 Numbers ) . $1*50. By Prof. T. H. Huxley. No. 4. Man’s Place in Nature. (Illustrated.) 16. The Origin of Species. 21. The Physical Basis of Life, etc. 36 4 Lectures on Evolution. (Illustrated.) 53* Animal Automatism, etc. 66. Technical Education, etc. By Prof. Geo. Rawlinson. 25. The Origin of Nations. 62. Religions of the Ancient World. (Doubl No., 30 cts.) By Herbert Spencer. 5. Education, Intellectual, Moral, etc. 9. The Data of Ethics. 17. Progress, its Law and Cause, etc. 34. The Philosophy of Style. By Th. Ribot. 46. The Diseases of Memory. 52. The Diseases of the Will. By Charles Darwin. 58. \ The Origin of Species. (Two Double 59. ) Nos., 30 cents each.) By Various Authors. 3. Physics and Politics. Walter Bagehot. 6. Town Geology. Chas. Kingsley. 7. The Conservation of Energy (Illustrated). Balfour Stewart. S. The Study of Languages. C. Marcel. 1 : 0 . Sound and Music (Illustrated). P. Blas- erna. 11. ) The Naturalist on the River Amazons. 12. ) Henry Walter Bates. 13. Mind and Body. Alex. Bain. M- Wonders of the Pleavens (Illustrated). Camille Flammarion. 15. Longevity: Means of Prolonging Life af- ter Middle Age. John Gardner, M.D. 20. Romance of Astronomy. R. K. Miller. 23. Scientific Sophisms. S. Wainwright. 24. Scientific Lectures (Illustrated). Prof. Helmholtz. 27. Landholding in England, /jos. Fisher. 28. Fashion in Deformity (Illustrated). W. H. Flower. 29. Facts and Fictions of Zoology (Illustr.). A. Wilson. 30. ] The Study of Words. Richard Che- 31. S nevix Trench. By William Kingdon Clifford. No. 22. Seeing and Thinking. 55. The Scientific Basis of Morals, etc. 65. Conditions of Mental Development, etc By Edward Clodd. 47. . The Chiklhood of Religions. 54. The Birth and Growth of Myth. 60. The Childhood of the World. By Grant Allen. k 6. The Evolutionist at Large. Vignettes from Nature. v — " j / By Richard A. Proctor. 1. Light Science for Leisure Hours. 19. Familiar Scientific Essays. 32. Hereditary Traits, etc. 61. Miscellaneous Essays. By Prof. John Tyndall. 1 2. The Forms of Water. (Illustrated.) ?8. Lessons in Electricity. (Illustrated.) 37. Six Lecturesfion Light. (Illustrated.) By Various Authors. 35. Oriental Religions. John Caird, and others. 38. ) Geological Sketches. Archibald 39. J Geikie. 40. Evidence of Organic Evolution. G. J. Romanes 41. Current Discussions in Science. W. M. Williams. 42. The Science of Politics. Fred. Pollock. 43. Darwin and Humboldt, Huxley, Agas- siz, and others. V 44. ) The Dawn of History, Edited by C. F. 45. J Keary, British Museum. 48. Life in Nature (Illustrated). Jas. Hinton. 49. The Sun. Judge N. T. Garr, Columbus, Ind. 50. ) Money and the Mechanism of Exchange 51 . 5 W. Stanley Jevons. 56. [illusions: A Psychological Study. 57. \ James Sully. 03. Progressive Morality. T. Fowler, Pres- sident Corpus Christi Coll., Oxford Univ. 64. The Distribution of Life. A.\ Russel Wallace and W. T. ThiseltoW Dyer. 67. The Black Death : the Great Pestilence of the 14th Century. J. F. C. Hecker, (Ready April io, 1885.) 3 0112 105256983 CROSBY’S VITALIZED PHOSPHIT COMPOSED CF THE NERVE-GIVING PRINCIPLES OF THE OX BRAIN AND THE EMBRYO OF THE WHEAT AND OM This is a standard preparation all physicians who treat nervous or mental disorders. It is not a secfPPthe formula is on every label. Its careful chemical composition has b&en superintended for twelve years by a Professor of Materia Medica, and its correct analysis vouched for by a Pro- fessor of Chemistry. Physicians alone have prescribed over a million bot- tles, curing nervous derangements and debility. It aids in the bodily, and wonderfully in the mental, growth of children It cures fretfulness and sleeplessness. By its special tonic effect upon the nerves, and its vitalizing influence on the blood of young persons, it brightens the eyes and gives good color to the lips ; it ensures a soft, smooth skin, glossy hair and handsome nails, so that these become an inheritance in later years. It feeds the brain and thus strengthens the intellect, so that study and deep mental application may be a pleasure, not a toil. It is used as a special brain tonic by all the best minds of this and othei countries. It strengthens the powers of digestion, is a positive cure for night- sweats, and prevents consumption. “ It amplifies bodily and mental powers to the present generation an ; ‘ proves the -survival of the fittest,’ to the next.” “There is no c*her Vital Phosphite ; none that is extracted from living vegetable and animal tissues.” Send for Circular. F. CROSBY CO., 56 West 25TH Street, New York.