Division Range Shelf ..... Received 1872 UNIVERSITY OF CALIFORNIA GIFT OF WILLIAM OILMAN THOMPSON. OXYHYDROGEN BLOW-PIPE. FOURTEEN WEEKS COURSE IN CHEMISTRY. J. DORMAN STEELE, A.M., PRINCIPAL OF ELMIRA FREE ACADEMY. "Bright and glorious is that revelation Written all over this great world of ours." LONGFELLOW. NEW YORK : PUBLISHED BY A. S. BARNES & CO., Ill &'l!3 WILLIAM STREET. 1867. f D 30 Entered according to act of Congress, in the year 1867, BY A. S. BARNES & CO., In the Clerk's Office of the District Court of the United States for the Southern District of New York. LITTLE, RENNIE & Co., GEORGE W. WOOD, STEBEOTYPEBS, PBINTEB, 430 BBOOXE STBEET, N. T. 2 DUTCH STBEET, N. T. PREFACE. IN the preparation of this little volume the author lays no claim to originality : his has been the far humbler task of endeavoring to express, in simple, interesting language, a few of the principles and practical applications of Chemistry. There is a large class of pupils in our schools who can pursue this branch only a single term, the time assigned to it in most institutions. They do not intend to become chemists, nor even professional students. If they wander through a large text-book, they become con- fused by the multiplicity of strange terms, which they cannot tarry to master, and, as the result, too often only " see men as trees walking." Attempts have been made to reach this class by omitting or dis- guising the nomenclature ; but this robs the science of its mathematical beauty and discipline, while it does not fit the student to read other chemical works or to understand their formulae. The author has tried to meet this wani by omitting thafc which is perfectly obvious to the eye that which everybody already knows that which could not be long re- tained in the memory and that which is essential 6 PREFACE. only to the chemist. He has not attempted to make a reference-book, lest the untrained mind of the learner should become clogged and wearied with a multitude of detail. He has sought to make a pleas- ant study which the pupil can master in a single term, so that all its truths may become to him "household words." Botany, Natural Philosophy, and Physiology are omitted, since they are now pur- sued as separate branches. Unusual importance is given to that practical part of chemical knowledge which concerns our every-day life, in the hope of bringing the school-room, the kitchen, the farm, and the shop in closer relationship. This work is de- signed for the instruction of youth, and for their sake clearness and simplicity have been preferred to rec- ondite accuracy. If to some young man or woman this becomes the opening door to the grander temple of Nature beyond, the author will be abundantly re- paid for all his toil. SUGGESTIONS TO TEACHERS. IT is recommended that in the use of this book the topical method of recitation should be adopted. So far as possible, the order of the subjects is uniform viz., Source, Preparation, Pro- perties, Uses, etc. The subject of each paragraph indicates a question which should draw from the pupil all the substance of what follows. At each recitation the scholar should be prepared to explain any point passed over during the term, upon its title being given by the teacher. Such reviews at eveiy recitation are of incalculable value. While some are reciting, let others write upon certain topics at the blackboard, and let the class criticise the thought, the language, the spelling, and the punctuation. Let each pupil keep a lecture-book, in which to record under each general head of the text-book all the experiments, descrip- tions, and general information given by the teacher in class. In order to accustom the scholar to the nomenclature, use the symbols constantly from the beginning : they may seem dull at first, but if every compound be thus named, a familiarity with chemical language will be induced that will be as pleasing as it will be profitable. If time will admit, hi addition, have weekly essays prepared by the class, combining information from every attainable source. ELEMENTARY CHEMISTRY. INTRODUCTION. CHEMISTRY treats of the specific properties of mat- ter and the composition of bodies. Examples : gold is yellow ; water is composed of two gases, hydrogen and oxygen. ORGANIC CHEMISTRY deals with those substances that have been produced by life. Examples : flesh, wood. INORGANIC CHEMISTRY is confined to those bodies that have not been formed by life. Examples : metals, rocks. An ELEMENT is a kind of matter which has never been separated into anything else. Examples : sil- ver, iron. There are about 65 in all, of which 52 are metals, and 13 metalloids or non-metallic substances. CHEMICAL AFFINITY is that force that causes the elements of matter to unite and form new com- pounds. It acts at distances so slight as to be in- sensible, and upon the most dissimilar substances : the more dissimilar the stronger the union. Ex- ample : a little chlorate of potassa and sulphur mixed in a mortar will not combine, but a slight pressure of the pestle will bring them within the range of at- ^raction, and they will burn with a loud explosion. 10 ELEMENTABY CHEMISTKY. Nothing in the nature or appearance of any element indicates its chemical affinity. We can only tell by trial with what it will combine. This attraction is not a mere freak of nature, but a law stamped upon mat- ter by God himself for wise and beneficent purposes. COMPOUNDS are utterly unlike their elements in all their properties. Examples : yellow sulphur and white quicksilver form red vermilion ; the inert nitrogen and the oxygen of the air constitute a cor- rosive acid aquafortis ; charcoal, hydrogen, and nitrogen produce the deadly prussic acid ; solid charcoal and sulphur make a colorless liquid ; poi- sonous and offensive chlorine combines with the brilliant metal sodium to form common salt. HEAT and LIGHT favor chemical action, and fre- quently develop an affinity where it seemed to be wanting. The former especially, by its expansive force, tends to drive the elements of a compound without the range of old attractions and within that of new ones. Examples : gun-cotton, when lying in the air, is apparently harmless, but a spark of fire will produce a brilliant flash, and it disappears as a gas : nitrate of silver turns black in the sun, by the action of the light. SOLUTION also aids in chemical change, as it destroys cohesion and leaves the atoms free to unite. Example : carbonate of soda and tartaric acid mixed in a glass will not combine, but a little water added will produce a violent effervescence. The CHEMICAL EQUIVALENT of an element is the ELEMENTAKY CHEMISTKY. 11 proportion by weight in which it unites with other elements. There is no chance-work in nature. No matter under what circumstances a compound is formed, the proportion of its elements is the same. Example : the carbonic acid produced amid the roar of a conflagration or the explosion of a volcano is iden- tical with that made in the quiet burning of a match. The ATOMIC THEOKY, which lies at the basis of chemistry, as now understood, supposes 1st. That bodies are composed of individual and unchangeable atoms. 2d. That the chemical equivalent represents the relative weight of the atoms of different kinds. 3d. That compounds are formed by the union of different kinds of atoms in the proportion of their equivalents, or multiples of their equivalents. 4th. That the chemical equivalent of a compound is equal to the sum of the chemical equivalents of its elements. NOMENCLATURE. The elements which were known anciently have retained their names. Those dis- covered more recently are named from some pecu- liarity. Examples : chlorine, from its green color ; bromine, from its bad odor. Of late the uniform termination um has been adopted. SYMBOLS. The first letter of the English name has been taken as the symbol. When that would produce confusion, the Latin name has been substi- tuted, and in some cases the second letter added. Examples : carbon and chlorine both commence with 12 ELEMENTARY CHEMISTRY. C ; so the latter takes Cl for its symbol. Silver and silicon both begin with Si, hence the former assumes Ag, from its Latin name, Argentum. If more than one equivalent of an element is used in forming a compound, this is shown by writing the number be- low the symbol. Example : O 2 indicates two equiv- alents of O. In the use of the following table, the symbol should recall, not the name of the element alone, but the relative weight of its atoms. Ex- ample : O means 8 parts of oxygen by weight. TABLE OF ELEMENTS AND EQUIVALENTS. ELEMENTS. Symbol. Equiv- alent. ELEMENTS. Symbol. Equiv alent. Aluminum, Al. 13.70 Niobium (Columbi- Antimony (Stibium), Sb. 129.00 um). Nb. 48.80 Arsenicum, Barium, As. Ba. 75.00 Nitrogen, 68.50 Norium. N. No. 14.00 Bismuth, Bi. 210.30 Osmium, Os. 99.40 Boron, Bo. 10.90 Oxygen, O. 8.00 Bromine, Br. 80.00 Palladium, Pd. 53.20 Cadmium^ Caesium, Cd. Cs. 56.00 1 Phosphorus, 123.40 ! Platinum, P. Pt. 31.00 98.60 Calcium, Carbon, Ca. C. 20.00 6.00 Potassium (Kalium), Rhodium, K. Ro. 39.00 53.20 Cerium, Ce. 46.00 Rubidium, Rb. 85.36 Chlorine, Cl. 35.50 Ruthenium, Ru. 52.11 Chromium. Cr. 26.30 Selenium, Se. 39.70 Cobalt, Co. 29.50 1 Silicon, Si. 14.00 Copper (Cuprum) Didymittm, Cu. D. 31.70 48.00 'Silver (Argentum), Sodium (Natrium), Ag. Na. 108.00 23.00 Erbium, E. Strontium, Sr. 43.80 Fluorine, F. 19.00 Sulphur, S. 16.00 Glucinum, Gl. 4.70 Tantalum, Ta. 68.80 Gold (Aurum), Au. 196.44 Tellurium, Te. 64.50 Hydrogen, H. 1.00 Terbium, Tb. Iodine, I. 127.00 Thallium, 51. Iridium, Ir. 98.60 Thorinum, Th. 59.50 Iron (Ferrum), Fe. 28.00 Tin (Stannum), Sn. 59.00 Lanthanum, La. 46.00 Titanium, Ti. 25.00 Lead (Plumbum), Pb. 103.60 Tungsten ( W o 1 - Lithium, L. 7.00 fram), W. 92.00 Magnesium, Mg. 12.16 Uranium, U. 60.00 Manganese, Mi. 27.48 Vanadium, V. 68.50 Mercury (Hydrargy- Yttrium, y. rum), Hg. 100.00 Zinc, Zn. 32.60 Molybdenum, M? 48.00 Zirconium, Zr. 22.40 Nickel, Ni. 29.501 ELEMENTARY CHEMISTBY. 13 A BINARY COMPOUND is a union of two elements, and in reading it the electro-negative is placed first and distinguished by the termination ide. Ex- amples : chlorine and sodium form chloride of sodi- um ; iodine forms iodides. In the case, however, of phosphorus, carbon, and sulphur, the termination uret is generally used. Example : iron and sulphur form sulphuret of iron. In writing the symbols the electro-positive element is placed first. An OXYD is a compound of O with an element. One equivalent of O is called the protoxyd ; two, the deutoxyd or binoxyd ; three of O to two of the other element, the sesquioxyd. Oxygen being negative to iron, when united they form an oxyd of iron, which is, therefore, written FeO ; the deutoxyd of iron is FeO 2 ; the tritoxyd of iron is FeO 3 ; the sesquioxyd, Fe 2 O a . Binary compounds are divided into three classes ACIDS, BASES, and NEUTRALS. An ACID is generally sour, and reddens blue lit- mus and green cabbage. It always unites with bases to form salts, which is the real test of an acid. Acids are of two kinds Oxacids and Hydracids ; the former contain O, the latter, H. The oxacids are named from the element with which the O unites, the termination indicating their strength ic the stronger and ous the weaker. Example : sul- phur forms two acids of different strength sulphu- ric and sulphurous. If an acid has been found containing more than the stronger, it takes the 14 ELEMENTABY CHEMISTRY. prefix per; if one having less O, the prefix hypo. Examples Chloric acid C1O 5 . Chlorous acid C1O 3 . Perchloric acid C1O 7 . Hypochlorous acid CIO. The hydracids combine the names of both ele- ments. Examples : hydrogen and chlorine form hydrochloric acid; hydrogen and sulphur make hydrosulphuric acid. A BASE is a substance that unites with an acid to form a salt. An alkali is a base that, in addition, has a soapy taste and feel, and changes red litmus to blue, and red cabbage to green. It turns the ium of its termination to a. Example : NaO is called the oxyd of sodium, and also soda. The alkalies neutralize the acids, and each restores the color re- moved by the other. SALTS are ternary compounds, being composed of three elements. They are formed by the union of an acid and a base. In naming a salt the termina- tion of the acid is changed an ic acid forming an ate compound, and an ous acid an ite compound. The equivalent of O combined in the base is omitted. Examples : NaO.SO 3 is read, sulphate of soda ; FeO.SO 3 , the sulphate of iron, and not the sulphate of the protoxyd of iron ; CaO.SO 2 , sulphite of lime. NEUTRALS have neither the properties of an acid ELEMENTAKY CHEMISTRY. 15 nor a base. Examples : NaCl, chloride of sodium ; KI, iodide of potassium. FORMULA is an algebraic statement of the symbols and relations of several compounds. The -f- sign indicates a feeble attraction or a mere mixture. The = sign indicates conversion into. The period de- notes a combination. The brackets and coefficients are used as in algebra. The following list of symbols are given for prac- tice and a thorough drill. PRINCIPAL ACIDS. Sulphuric Acid (Oil of Vitriol) 80s Nitric Acid (Aquafortis) , NOs Chloric Acid C1O 5 Phosphoric Acid POs Carbonic Acid CO2 Sulphurous Acid SO2 Nitrous Acid NO 4 Hydrochloric Acid HC1 THE ALKALIES. P otassa (Potash) KO S oda NaO A mmonia NHs L ime CaO M agnesia MgO SALTS. Sulphate of Iron (Green Vitriol) . p FeO.SOa Sulphate of Copper (Blue Vitriol) CuO . SOa Sulphate of Zinc (White Vitriol) ZnO. SOa 16 ELEMENTABY CHEMISTRY. Sulphate of Potash KO.SOs Chlorate of Potash KO.ClOs Nitrate of Soda NaO . NO 5 Nitrate of Potash (Saltpetre) KO . NO 5 Carbonate of Lime (Limestone, Chalk) CaO.CO2 Carbonate of Soda (Soda) NaO . CO 2 Bicarbonate of Potash (Saleratus) KO .2CO 2 Sulphite of Soda NaO.SO 2 Sulphide of Iron FeS % Sulphuret of Iron FeS Chloride of Sodium (common salt) NaCl Bhioxyd of Manganese MnO 2 Protoxyd of Hydrogen (water) HO juioxyd of Iron (iron-rust) Fe 2 Os MATHEMATICS OF THE LAW OF EQUIVALENTS. The beauty and simplicity of the Divine law of harmony that runs like a silken thread through all nature, giving unity and completeness everywhere, are best seen by some practical applications. It is evident, from the fourth principle of the atomic theory, that the proportion of any element in a compound is equal to its equivalent divided by the equivalent of the compound. Example: HO 1 + 8=9; hence the proportion of H in any quantity of water is , and the proportion of O is -f. Again : the propor- tion of that element or constituent in a given weight of the compound must be equal to the weight mul- tiplied by this fraction we have just named. Ex- ample : In 4 Ibs. of HO there are 4 x-J- lb. of H=$ lb., and 4xf lb. of O=- 3 /=3f Ibs. For conveni- ELEMENTARY CHEMISTRY. 17 ence we can put this thought into the following al- gebraic form, under which should be solved the ex- amples which follow, and many other similar ones, which the ingenuity of teacher and scholar will sug- gest. The book should be searched for symbols of compounds, and this part referred to throughout the study. . . ( Equivalent of the constituent Weight of one constituent=weight of given quantity -J =? .- \ Equivalent of the compound 1. In making O from chlorate of potash (KO. C1O 5 ), how much can be obtained from two pounds of the salt? 2. In making H zinc is used. How much sulphate of zinc (ZnO.SO 3 + 7HO) will be formed from 2 Ibs. of the metal? 3. How much S0 3 will be required to make 50 Ibs. sulphate of iron (FeO.SO 3 + 7HO) ? 4. The equivalent of the chloride of sodium (salt) is 58.5. In 10 Ibs. there are 6yf T Ibs. of sodium ; what is the equivalent of Cl ? 5. In 20 grains of bromide of potassium there are G^V grains of potassium ; the equivalent of potassium being 39, what is the equivalent of the bromide of potassium? 6. In 14 Ibs. of iron-rust (Fe 2 O 3 ) how much O ? 7. In 20 Ibs. of glass (NaO.SiO 2 + CaO.SiO 2 ) how many Ibs. of sand (SiG 2 ) ? 8. In a 25 Ib. sack of salt (NaCl) how many Ibs. of the metal sodium ? INORGANIC CHEMISTRY. THE METALLOIDS. OXYGEN. Symbol, O Equivalent, 8 Specific Gravity, I.I. THE name O means acid-former, and was given because it was supposed to be the essential princi- ple of all acids ; but hydrogen has since been found to possess the same property. . Source. O is the most abundant of all the ele- ments comprising | of the air, -f of the water, J of all animal bodies, and \ of the crust of the earth. Preparation. The simplest method of making O for experimental purposes is to heat a mixture of chlorate of pot- ash and black oxyd of manga- nese in a retort, and collect the gas over a pneu- matic cistern, as in the accompany- ing illustration. . OXYGEN. 19 The reaction the chemical change is as fol- lows: KO.C1O 6 KC1 6O The Cl of the chloric acid unites with the K of the potash, forming KC1, chloride of potassium ; and the 5 atoms of O in the chloric acid and the atom of O in the potash, making 6 atoms of O, pass off as a A Curious Fact. If the chlorate of potash were heated alone, when the requisite temperature was reached the gas would be liberated with very great rapidity. Sometimes, indeed, the change would be instantaneous the solid of scarcely a cubic inch becoming in the twinkling of an eye a gas of 300 cubic inches, and, with an explosion like gunpowder, rending the retort into a thousand fragments. If, however, we mix with the chlorate of potash a little black oxyd of manganese, the gas will come off quietly and safely, a bubble at a time. At the con- clusion of the process, the MnO 2 (the binoxyd, or black oxyd of manganese) will be found unchanged. The reason of this wonderful action is beyond our comprehension. It would seem that powdered glass or sand should produce the same result ; but, on trial, they fail. This influence of one body over another, by its mere presence, is called ca- talysis. 20 ELEMENTARY CHEMISTRY. Properties. O has no odor, color, or taste. It combines with every element except fluorine. From some of its compounds it can be set free by the stroke of a hammer, while from others it can be liberated only by the most powerful means. Its union with a substance is called oxydation, and the product an oxyd. It is a most powerful supporter of combustion. Example: By blowing quickly upward upon a candle extinguish the flame, and leave a glowing wick. If this be plunged into a jar of pure O, it will burst into a brilliant blaze. The experiment may be repeated many times before the gas is candle in oxygen. exhausted. Carbonic acid is formed by the combustion. Example : If a watch-spring be straightened in a spirit-lamp, and then tipped with melted sulphur, on ig- niting this and lowering it into a jar of O, the steel will crackle into a shower of fiery stars, and melted globules of oxyd of iron will fly in watch-spring in oxygen. every direction. OXYGEN. 21 Example : Ignite a bit of sulphur placed on a stand, and invert over it a jar of O : it will burn with a beau- tiful blue light, and the fumes of sulphurous acid (SO 2 ) will circle about the receiver in cu- rious concentric rings. Sulphur in oxygen. Example : Place in the bottom of a " deflagrating spoon" a little fine, dry chalk ; then wipe a bit of phosphorus very carefully and quickly between pieces of blotting- paper ; lay this upon the chalk, and, hold- ing the spoon over a large jar of O, ig- nite the phosphorus with a heated wire, and lower it steadily into the gas. The phosphorus will burst into a blinding flood of light, while dense fumes of phos phoric acid (PO 6 ) will roll down the sides of the jar. THE DESTKUCTIVE AGENT OF THE Am. is the ac- tive principle of the atmosphere. It is destructive in all its effects. Comprising one-fifth of common air, it Phogphoru8 in oxygen . The phosphoric 22 ELEMENTAKY CHEMISTRY. is all around us, and, like a lurking lion, constantly on the watch for a chance to spring upon and devour something. "We gather a basket of luscious peaches, and put them out of the way of the children ; but we cannot outreach the slyest pilferer of all the O and soon we will find the fruit covered with the prints of invisible teeth. Black spots appear, and we say they are decaying ; it is only the O feasting upon them, and in a month it will devour them, skin and all. To prevent this, we put our fruit in a glass can, heat it to expel the O, seal it up tightly, and then it is safe from this chemical plunderer. "We open the damper of the stove, and the air rushes in. The O immediately attacks the fuel. Each pair of atoms catches up an atom of C between them, and flies off into the air as carbonic acid. An animal dies. The O is on the alert ; and, the in- stant his victim expires, and sometimes a little sooner, he is so anxious to commence, he begins to remove that which will soon be an offence to all sen- sitive nostrils. We accidentally cut a finger, and soon find the unwelcome O tugging away at the quivering nerve beneath. The keen throb with which an unsuspected hollow in a tooth is revealed to us, announces the entrance of the foe at an un- guarded breach. The HO in the cistern becomes foul and putrid. We uncover it. In rushes the O, picks up every atom of impurity, and drags it to the bottom. The thick sediment we find when we clean it t e next summer, shows how faithfully it did its OXYGEN. 23 work.* We use our writing-fluid, and the words look pale and dejected. In a few hours we return, and even the letters stand out bold and clear. Noiselessly uniting with the iron of the ink, the skilful intruder has not disturbed the most delicate tracery in taking possession. The blacksmith draws a red-hot iron from his forge. The O seizes the op- portunity while the metal is glowing, and bites off great scales of the black oxyd of iron (Fe 3 O 4 ) that fly in every direction. We wipe our knives and forks, and carefully lay them away ; but if we have left on them the least particle of moisture, as HO favors chemical change, the vigilant O will find it, and, if unmolested, will never stop until it has eaten the whole of the feast we have provided. But as heat is also productive of chemical action, and the Fe is now cold, it cannot combine as vigorously as at the blacksmith's forge ; therefore, the compound is a lower one, the red oxyd of iron (Fe 2 O 3 ) or com- mon iron-rust, as we see it on stoves and other utensils. O IN THE HUMAN SYSTEM. We take the air into our lungs. Every three minutes all the blood in the system makes the tour of the body, and comes to * " As the vessel sets sail from London, the captain fills the water-casks with water from the river Thames, foul with the sewage of the city, and containing 23 different species of animalcules ; yet, in a few days, the O contained in the air dissolved by the HO, will have cleansed it, and the HO will be found sweet and wholesome during the voyage." 24 ELEMENTARY CHEMISTRY. the lungs. Now the blood is full of little iron disks, or gas-bags. These, when old, assume a tawny hue, like the decayed leaves of autumn, shrivel up and die, millions of them perishing at every breath we draw. But when young and vigorous, they take up the O and cany it to all parts of the body, deposit- ing it wherever it is needed. Here the O revels in high life. It sweeps tingling through every artery and vein, distends each capillary tube, sends the quick flush to the cheek, snatches up its portion of the food that comes out of the stomach, gnaws away at the nerves and tissues, eats up every worn- out muscle and all waste matter, until at last it comes back through the veins black and thick with the pro- ducts of its toil the cinders of the fire within us. COMBUSTION AND HEAT. All processes of fermen- tation, of decay, of putrefaction, of fire, are called, by the chemist, by one name combustion, or oxyd- ation. They are simply produced by the union of O with the substance. They differ only in the time employed in the operation. If O unites rapidly, we call it fire ; if slowly, decay. Yet the process and the products are the same. A stick of wood is burned in my stove, and another rots in the woods, and the chemical change is identical. In the com- bustion of an atom of O, a certain amount of heat is liberated. Hence, the house that decays in twenty years, gives out as much heat during that time as if it had been swept off in a fierce conflagration in as many minutes. OXYGEN. 25 THE HUMAN FUBNACE. The body is a stove in which fuel is burned, and the chemical action is pre- cisely like that in any other stove. This combustion liberates heat, and our bodies are kept warm by the constant fire within us. We thus see why we fortify ourselves against a cold day by an extra full meal. When there is plenty of fuel in our human furnaces, the O burns that ; but if there be a deficiency, the destructive O must still unite with something, so it gnaws away at our flesh ; first the fat, and the man grows poor ; then the muscles, and he grows weak ; finally the brain, and he becomes crazed. He has simply burned up, as a candle burns out to dark- ness. O PEODUCES MOTION. The action of O in the movement of the muscles is very singular. In order to move a limb, the muscle must contract. So the O unites with a part of the muscle, destroys its structure, and so shortens it. Thus every movement of a limb, every wink of the eye, even, is performed by the disintegration of the muscle used. The truth of this is shown very clearly when we remem- ber that, as soon as we begin to perform any unusual exercise, we commence breathing more rapidly, showing that we need more O to unite with the muscles to perform the work. In very violent labor, as in running, we are compelled to open our mouths, and take in great swallows of oxygen. This roaring fire within elevates the temperature of the body, and we say " we are so warm that we pant." Really it is 26 ELEMENTAEY CHEMISTEY. the reverse. The panting is the cause of our wamth. We need O, then, not only to keep us warm, but also to do all our work. Cut off its supply, and we grow cold, the heart struggles spasmodically for an in- stant, but the motive power is gone, and the wheels of life soon stand still.* THE BURNING OF THE BODY BY O. A man weighing 150 Ib. has 64 Ib. of muscle. This would be burned in about 80 days of ordinary labor. As the heart works day and night, it burns out in about a month. So that we have a literal " new heart" every thirty days. We thus dissolve, melt away in time, and only the shadow of our bodies can be called our own. They are like the flame of a lamp, which ap- pears for a long time the same, since it is " cease- lessly fed as it ceaselessly melts away." The rapidity of this change in our bodies is remarkable. Says Dr. Draper : " Let a man abstain from water and * During sleep, the organs of the body are mostly at rest, ex- cept the heart. To produce this small muscular exertion very little O is required. As our respiration is, therefore, slight, our pulse sinks, the heat of our body falls, and we need much addi- tional clothing to keep warm. Animals that hibernate show the same truth. The marmot, for instance, in summer is warm- blooded; hi the winter its pulse sinks from 140 to 4, and it becomes cold-blooded. The bear goes to his cave in the fall, fat and plump ; in the spring he conies out lean and lank. Cold-blooded animals have very inferior breathing apparatus. A snake, for example, has to swallow air by mouthfuls, as we do water. Others have no lungs at all, and breathe hi a little air through their skin, enough to barely exist. Is it strange they are cold-blooded ? OXYGEN. 27 food an hour, and the balance will prove he has be- come lighter." At night a person is not quite so tall as in the morning. A French physiologist says his son lost an inch by a single night's dancing. This action of O, so destructive wasting us away constantly from birth to death is yet essential to our existence. Why is this ? Here is the glorious paradox of life. We live only as we die. The moment we cease dying, we cease living. All our life is pro- duced by the destruction of our bodies. Hence the necessity for food to supply the constant waste of our system, and for sleep to give nature time to re- pair the losses of the day. Thus, also, we see why we feel exhausted at night and refreshed in the morning. O THE COMMON SCAVENGER. God has no idlers in his world. Each atom has its use. There is not an extra particle in the entire universe. So the O collects every waste substance, picks up every strag- gler, and returns it to the common stock, for use in nature's laboratory. In performing this task, its mission is most important and necessary. It sweet- ens water, it keeps the avenues of the body open and unclogged, it preserves the air wholesome. Oxygen is, in a word, the universal scavenger of nature. No matter can hide away from its keen eye. Every dark cellar of the city, every recess of the body, every nook and cranny of creation, finds it waiting ; and the instant an atom is exposed, the oxygen pounces upon it. A leaf falls, and the forthwith commences 28 ELEMENTARY CHEMISTRY. its destruction. A tiny twig, far out at the end of a limb, dies, and the O immediately begins its removal. A pile of decaying vegetables, a heap of rubbish, the dead body of an animal, a fallen tree, even the houses we erect for our shelter the very instant they are built, all are gnawed upon by what we call the " insatiate tooth of time." It is only the constant corrosion of this destructive agent oxygen. ACTION OF PURE O IN THE BODY. The action of undiluted oxygen on the animal system is exhilarat- ing in the highest degree. A rabbit immersed in a receiver of this gas soon feels its effect, bounds off into a delirium of excitement, and in a few hours by this quick combustion burns out its little lamp of life. Were we to breathe pure O, the fiery gas would leap through our arteries like a hungry tiger, the heart would throb against the ribs with the stroke of a trip-hammer, the veins would dilate with the increasing tide of blood, the eyes would glisten and glare : the gestures and motions would be at first quick, lively, vivacious, then hurried and restless, then eager and startling, at last furious and raving ; and if the inhalation of the gas still continued, stark insanity would end the drama of life. KESULTS IF THE AIR WERE PURE O. Were the air pure O, the fire element would run riot everywhere. Our lamps would burn with the oil they contain. Our stoves would blaze with a shower of sparks. A fire once kindled would spread with ungovernable velocity. In a conflagration, not only would the OXYGEN. 29 timber of a ho;ise burn, but the nails, the foundation, and even the very water poured upon it to extinguish the flames. OZONE. Ozone is an dttoircpic form of O i. e., a form in which the element itself is so changed as to have new properties. It is always perceived during the working of an electric machine, and is then called "the electric smell." It has also been de- tected near objects just struck by lightning. The electricity of the atmosphere is supposed to have something to do with its formation. Its test is a paper wet with a mixture of starch and iodide of potassium (KI). The ozone sets free the iodine, and that unites with the starch, forming the blue iodide of starch. Its identity with is easily shown. Ex- ample : Pour a little ether into a jar of common air, and stir in its vapor a heated glass rod. The O will be immediately changed into its allotrop- ic form ozone, which can be recognized by its pun- gent odor and the test just named. If the ozone be afterward passed Making ozone, through a red-hot tube, it will come out the original O. Ozone is much more corrosive even than oxygen. It bleaches powerfully, and is a rapid disinfectant. A piece of tainted meat plunged into a jar of ozone 30 ELEMENTARY CHEMISTRY. is instantly purified. Its abundance in the air pro- duces influenzas, diseases of the lungs, etc. ; its ab- sence, fevers, agues, etc. NITROGEN. Symbol, N .... Equivalent, 14.... Specific Gravity, 0,97. This gas is called nitrogen because it exists in nitre. Sources. Nitrogen is found largely in ammonia and nitric acid. It forms \ of dried flesh, f of the at- mosphere, and exists abundantly in mushrooms, mustard, cabbage, horse-raddish, turnips, etc. The peculiar odor of burnt hair or woollen is given by the N compounds they contain. Preparation. It is prepared by putting in the centre of a deep dish of water a little stand several inches in height, on which a bit of phosphorus may be laid and ignited. As the fumes of phosphoric acid ascend, invert a receiver over the stand. The phosphorus will consume all of the O of the air contained in the jar, leaving the N. As the Making nitrogen. water ^ tlie plate riseg) add more as needed. It should occupy ^ of the receiver. The jar will at first be filled with white fumes (PO 5 ), but the water in a few minutes will absorb these. Another Method. Nitrogen may also be pre- pared in large quantities in the manner shown in the NITROGEN. 31 illustration. At the left is a stream of water which falls through a funnel tube into a " Woulfe's bottle." The U-shaped tube is filled with bits of chloride of Making nitrogen. calcium to absorb the moisture ; and a second tube should be added, filled with pumice-stone, moistened with caustic potash, to deprive the air of its carbonic acid. The long tube is filled with copper turnings, heated by the furnace-fire. The air from the bottle is driven by the f ailing water up through the U tubes, where it loses its water and carbonic acid; thence among the red-hot copper-turnings, whicji unite with its O : after which the N, deprived of all its com- panions, bubbles up through the water into the receiver. 32 ELEMENTAKY CHEMISTRY. Properties. All descriptions of nitrogen are of a negative character. It neither burns nor permits anything else to burn. It neither supports life nor destroys it. Yet a candle will not burn in it, and a person cannot breathe it alone and live, simply be- cause it shuts off the life-giving oxygen. So will a person drown in HO, not that the water poisons him, but because it fills his lungs, and shuts out the air. N does not unite with any of the metals. The insta- bility of all its compounds is its striking peculiarity. For instance, it may be induced to join its fortune with iodine, but so gingerly, that if we even tread heavily in the room where it is kept, it will leave its partner in high dudgeon, and bound off into the air with a tremendous explosion. Uses. RELATION OF N TO ORGANIC SUBSTANCES. Four-fifths of each breath that enters our lungs is N ; yet it comes out as it went in, leaving the remaining fifth, O, to perform its wonderful mission within our bodies. One-fifth of our flesh is N, yet none of it comes from the air we breathe. We obtain all our supply from the lean meat and vegetables we eat. Plants breathe the air through the leaves their lungs ; yet they do not appropriate any of the N obtained in this way, but rely upon the ammonia and nitric acid their roots absorb from the soil. N enters the stove with the O : the latter unites with the fuel ; but the former, disdaining any such work, passes on out of the chimney. Even from a blast- furnace, where iron instantly melts like wax, the N NITROGEN. 33 * comes forth without the smell of fire upon it. So unsocial is it, that it will not affiliate directly with any organic substance. We must all, animals and plants, depend upon finding it bound hand and foot in some chemical compound, and so appropriate it to our use. But even then we hold it very loosely indeed. The tendency of flesh to decompose is mainly owing to the instability of the N in its composition. DIFFERENCE BETWEEN N AND O.* We see now how different N is from O. The one is the conservative element, the other the radical. But notice the nice planning shown in the adaptation of the two to our wants. O, alone, is too active, and must be re- strained. Were the air pure O, our life would be excited to a pitch of which we can scarcely dream, and would sweep through its feverish, burning course in a few days. Four parts of the negative N just restrain the O within governable limits, adapt it to our needs, and make it our useful servant. O AND N COMBINED. Separately, either element of the atmosphere would kill us. The fiery O and the inert N combined give us the golden mean. The O now quietly burns the fuel in our stoves and keeps us warm ; licks up the oil in our lamps and gives us light; corrodes our bodies and gives us strength; * The difference between these two gases can be best illustrated by having a jar of each, and rapidly passing a lighted candle from one to the other : you will extinguish the light hi the first, and relight the coal in the second. By dexterous management this may be repeated a dozen times. 2* ELEMENTARY CHEMISTRY. cleanses the air and keeps it fresh and invigorating ; sweetens foul water and makes it wholesome ; works all around and within us a constant miracle, yet with such delicacy and quietness that we never perceive or think of it until we see it by the eye of science. NITROUS OXYD, NO LAUGHING GAS. Preparation. This gas is made by heating nitrate of ammonia. The reaction is as follows : . NO 5 O + 2NO The atom of N and two atoms of from the nitric acid unite with the atom of N from the ammonia, forming2NO.The four atoms of H in the ammonia unite with three atoms of O in the nitric acid and the one atom of O in the ammonia, forming 4 atoms Properties. It supports combustion almost equal- ly with O, and, like it, is colorless and odorless. It NITKOUS OXYD LAUGHING GAS. 35 is soluble in HO, and liquefies at 45 9 F., with a pressure of 50 atmospheres. It has a sweet taste, and is chiefly noted for its anaesthetic properties. ACTION ON HUMAN SYSTEM. When breathed, it produces a species of intoxication. The feeling is generally one of perfect bliss and contentment. A feverish glow overspreads the body, and a thousand delightful visions pass before the mind. The cares and troubles of life " Fold their tents like the Arabs, And as quiet steal away." A wild, delicious, dreamy joy spreads through the system, and annihilates all idea of time and space. The first inhalation of the gas sometimes causes bursts of laughter, hysterical weeping, or loud, un- meaning talking. Then succeeds a glow of warmth, first felt in the extremities, followed by a prickly, be- numbed sensation, a confusion of ideas, noises in the ears (frequently compared to the vibration of an engine from one side of the head to the other), and occasionally flashes of light before the eyes. With this stage all sensation and voluntary motion cease. Without any ability to act, one is yet frequently en- tirely conscious of all that takes place. During this, the anaesthetic state, perfectly painless operations can be performed. Often the patient will awake, re- membering all that has occurred, yet having felt no pain. For scientific purposes, or for amusement, the 36 ELEMENTABY CHEMISTRY. inhalation is stopped before the anaesthetic stage is reached. One can administer the gas to himself with perfect safety after a few trials. Before inhaling, he may decide what he will do while under its influ- ence, laugh, sing, declaim, etc. ; and keeping this idea and no other upon his mind while breathing, he will find himself irresistibly impelled to perform it. If he has no especial thought in his mind, he is left to the inspiration of the moment, and may do any ab- surd thing the occasion may suggest, from holding his nose and bowing continually to the audience, to clearing the stage of its occupants. The gas does not "bring out the natural disposition of the person," as some have believed. As soon as its influence passes off, the hand seeks the forehead with return- ing consciousness, the eye resumes its natural ex- pression, the pulse sinks to a slightly quickened beat, and the dream is over. EXPLANATION. The exciting effect of this gas is due to the excessive supply of O it furnishes the sys- tem. "When the carbonic acid gas, formed by this unusual combustion, accumulates in the veins, by its narcotic influence it produces a temporary insensi- bility. Caution. The utmost care should be used in pre- paring NO. It should stand over HO at least 12 hours before inhalation, although agitation with sev- eral gallons of HO in the gas-bag is a safe precau- tion. No one should ever breathe it who is not in good health at the time, who is troubled with a rush NITRIC ACID. 37 of blood to the head, any lung or heart disease, or is of a plethoric habit. With proper caution, no ac- cident need ever occur. NITRIC ACID (AQUAFORTIS), NO 5 . This acid is found in nature, in combination with soda or potash, and is obtained in a separate state by the addition of a stronger acid, which drives off the weaker and usurps its place. Thus, taking KO.NO 5 , and adding SO 3 , the following chemical change ensues, while the acid is collected in a re- ceiver, cooled by dropping water : KO.NO 5 4- S0 3 KO.SO 3 It is formed in small quantities in the atmosphere by the union of its elements during the passage of electricity, as in a thunder-storm, and being washed to the earth by rain, is absorbed by the roots of plants. Properties. It is an intensely corrosive, poison- ous liquid. When pure, it is colorless, but as sold, Making NO 5 38 ELEMENTAKY CHEMISTRY. has commonly a golden color, from the presence of the red fumes of nitrous acid, produced by the de- composing action of the light. It has been obtained in the form of brilliant transparent crystals, but is always found dissolved in HO, sometimes of twice its own weight, never less than J. In strength, it is next to SO 3 . It stains the skin, wood, etc., a bright yellow. Uses. It gives up its O very readily, and thus corrodes any substance with which O will combine. It is employed in dyeing woollen yellow, and in sur- gery for cauterizing the flesh. It dissolves most of the metals, and in combination with HC1, forms aqua- regia, the only solvent of gold. It etches the lines in copperplate engraving, and the beautiful designs on the blades of razors, swords, and other steel utensils. The process is very simple. The surface is covered with a varnish impervious to NO 5 ; the de- sired figure is then sketched in the varnish with a needle. The NO 5 being poured on, oxydizes the metal in the delicate lines thus laid bare. ACTION ON THE METALS. If a bit of Sn be placed in NO 5 , the acid will immediately give up to it three atoms of its O, making the metal an oxyd (SnO 2 ), and reducing itself by the operation to NO 2 (nitric oxyd) ; this passes off into the air as a gas, and eagerly seizing upon two atoms of O in the air, becomes NO 4 (nitrous acid), which we readily recognize by its brilliant, red-colored fumes. If, instead of the Sn, Cu be used, the action is somewhat different. A NITKIC ACID. 39 portion of the acid unites with the Cu, forming an oxyd (CuOj ; but another portion instantly com- bines with CuO, making CuO.NO 5 . This we detect by the deep blue color it gives to the liquid. If we now evaporate the HO from this solution, we will obtain beautiful blue crystals of the salt. The experi- ment may be performed with the apparatus shown in the cut. The nitric Making NO 2 oxyd, NO 2 , caught in the receiver, will be found color- less, while, on admitting a bubble of air, blood-red fumes of NO 4 will fill the jar. AMMONIA, NH 3 . ^his gas is also called hartshorn, because in England it was formerly made from the horns of the hart. It received the name ammonia, by which it is now more generally known, from the temple of Jupiter Ammon, near which sal-ammoniac, one of its compounds, was once manufactured. The aqua-ammonia of the shops, which is merely a strong solution of the gas in HO, is obtained from the in- cidental products of the gas-works in large quanti- ties. Water absorbs from 400 to 500 times its own bulk of ammonia. "When undiluted, it will produce 40 ELEMENTARY CHEMISTRY. a blister, and should, therefore, be very much weak- ened before being tasted or touched. It is a strong alkali, and turns the vegetable blues to greens ; but owing to its volatility this change of color is only temporary. It is, therefore, sometimes termed " the volatile alkali." Its test is hydrochloric acid, HC1. Example : If we bring a stopple wet with HC1 near this gas, it will instantly reveal itself by a dense cloud of white fumes, the chloride of ammonium, sal-ammoniac, which floats in the air like smoke. The antidote of ammonia is vinegar. Its pungent odor can always be detected near decaying vegetable or animal matter. Smelling-bottles are filled with a mixture of finely powdered sal-ammoniac and lime. By this method, ammonia is also made in the arts. The process is hastened by applying heat. The re- action is as follows : NH 4 .C1 + CaO rva NH 3 + Ca.Cl + HO One atom of H of the sal-ammoniac unites with the O of the lime, forming HO. The calcium of the lime combines with the chlorine, producing chloride of calcium, and the NH 3 is set free as a gas which may be absorbed by water, as in the adjoining illus- tration, thus forming aqua-ammonia. Nascent state. If K and H, the elements of NH 3 , be mixed in a receiver, they will not unite chen> NITBIC ACID. 41 Making NH, ically, owing to the negative character of N, of which we have before spoken. "When, however, any substance is decom- posed which contains both of them, as bit- uminous coal, flesh, etc., at the very in- ,stant of their separa- tion from their com- pounds, in the first feeling of their loneli- ness, as it were, they ^1 will combine and form NH 3 . This moment, when elements are thus in the act of leaving their compounds, is called their "nascent state." CHLORIDE OF AMMONIUM, MURIATE OF AMMONIA, SAL- AMMONIAC, NH 4 C1. In the ammoniacal liquors just named, and in the distillation of horns, hoofs, horse- flesh, woollen rags, etc., carbonate of ammonia is formed. By mixing this with HC1, that acid drives off the CO 2 , and takes its place, thus producing chloride of ammonium. On evaporating the solu- tion, tough, fibrous crystals are obtained. They reveal no trace of the pungent ammonia, yet it can be easily set free, as we have already seen. Sal- ammoniac is soluble in HO ; is used in medicine, and also in soldering, the HC1 it contains dissolving the coating of the oxyd of the metal, and preserving the surfaces clear f jr the action of the solder. 142 ELEMENTARY CHEMISTRY. HYDROGEN. Symbol, H .... Equivalent, I Specific Gravity, .069. Hydrogen means literally a generator of water. Preparation. It is always obtained by the decomposition of HO, of which it forms part by weight. If we place in an evolution flask (a common junk bottle will answer) bits of zinc, and then pour through the funnel tube sulphuric acid (SO 3 ) and HO, the gas will be evolved abundantly. The reaction is as follows : Zn + SO S + HO Making hydrogen. ZnO. H The zinc decomposes the HO uniting with the O, forming ZnO, and setting free the H, which passes off as a gas. But the ZnO would soon form a coat- ing over the metal, and protect it from the HO ; this the SO 3 prevents by combining with the ZnO, form- ing ZnO.SO 3 (white vitriol), and so keeping the sur- face of the zinc bright and the action constant. The HYDROGEN. 43 black specks which appear floating about in the so- lution are charcoal from the Zn. The white vitriol which is formed soon gives the mixture a milky -white appearance. By evaporating the HO, the crystals of this salt can be obtained. Properties. H prepared in this manner has a disagreeable odor, from various impurities in the materials used. When pure, like O, it is colorless, transparent, and odorless. Its atoms are the small- est of any known element ; and in attempts made to liquefy the gas, it leaked through the pores of the thick iron cylinders in which it was compressed. It is the lightest of all bodies, being only T V as heavy as common air. It is not poisonous, although, like N, it will destroy life or combustion by shutting out the life-sustainer, O. When inhaled, it gives the voice a ludicrously shrill tone. It can be breathed for a few moments with impunity, if it be first passed through lime-water to purify it. Owing to its light- ness, it passes out of the lungs again directly. Its levity suggested its use for filling balloons, and it has been used for that purpose;* but coal gas, which contains much H, and is cheaper, is now preferred. COMBUSTION OF H. A lighted candle, plunged into * We read, in accounts of ftes at Paris, of balloons ingeniously made to represent various animals, so that aerial hunts are de- vised. The animals, however, persistently insist upon ascending with their legs up a circumstance productive of great mirth hi the crowd of spectators. 44 ELEMENTARY CHEMISTRY. an inverted jar of this gas, is extinguished, while the gas itself, takes fire, and burns with a pale blue flame. One atom of the O of the air unites with an atom of the H, and the product of the combustion is HO, which may be condensed on a cold tumbler, held over a jet of the burning gas, as in the accompanying figure. Mixed Gases. A mixture of two parts, by measure, of H, with one part of O, or five parts of common air, will ex- plode with a deafening report. The bulky gases being instantly condensed into a mere drop of HO, only y^VjF as large, a vacuum is produced, and the Candle in H. Burning H. particles of air rushing in to fill the empty space, by their collision against each other, produce the stun- ning sound. "While the detonation is so great, the force is slight, as may be shown by exploding the bubbles in the hand. The two gases may be mingled in the light proportion and kept for years, and there HYDROGEN. 45 will be no change. The atoms lie against each other quietly, " cheek-by-jowl," without any manifestation of their chemical affinity, when suddenly, at the con- tact of the merest spark of fire, they rush together with a crash of thunder, and uniting, form the bland, passive liquid water. ACTION OF PLATINUM SPONGE. A piece of platinum sponge placed in a jet of H will ignite it. This curious effect seems to be produced in the following way : The atoms of H and the O of the air are brought so closely together in its minute pores that they unite, and the heat thus produced sets fire to the gas. HYDROGEN TONES.* A singular illustration of the laws of sound can be given by simply holding a long glass tube, by means of a suitable clamp, over a minute jet of burning H. At first no effect will be produced ; but as we slowly introduce the jet further and fur- ther into the tube, a faint sound is heard, apparently * Another illustration of singing hydrogen may be represented in the following manner: Make a jar of heavy tin, in the form of a double cone, 12 inches long and 4 inches in diameter. At one apex fit a nozzle and cork, at the other, make several minute openings. Covering these openings with sealing-wax, and draw- ing the cork, fill the jar with H, and replace the cork. When ready for use, hold the jar in a vertical position, remove the wax from at least one orifice, ignite the H at that point, and draw the cork. Still hold the jar quietly, and in a minute or two the tiny jet of H will begin to sing like a swarm of musquitoes, buzzing and humming in the most aggravating way until, most unex- pectedly, the scientific music ends in a loud explosion. 46 ELEMENTARY CHEMISTRY. in the far-off distance. This gradually approaches, and finally bursts into a shrill, continuous, musical note the key-note of the heated column of air within the tube. The cause of this is thought to be Hydrogen Tones. that the flame is momentarily extinguished and re- lighted with a slight explosion, and these, rapidly repeated, produce the musical note. Indeed, these explosions may be made so slow that the quivering WATER. 47 of the flame can be seen, and the sound cease to be continuous as before. Let us now place the tube at a point where no clapping of hands or unusual sound will start it into song. Let various tones be pro- duced from a violin, and we will find the flame re- sponding only to that tone which is the key-note of the tube, or its octave. The violin player will have perfect control of this scientific music, and can start, stop, or throw it into violent convulsions, even across a large hall. Tubes of different sizes and lengths will give tones of diverse character and pitch. The waves of sound from the instrument augmenting or interfering with those in the tube will probably ac- count for these phenomena. WATER. Symbol, HO-..- Equivalent, 9-.-- Freezes at 32F Boils at 2f2F. The composition of HO is proved by analysis and synthesis i. e. t by separating the compound into its elements, and by combining the elements to produce the compound. We can analyze it in the manner already shown in preparing H, or by passing through it a galvanic current, when the O will appear in bubbles of gas at the positive pole, and the H in a similar way at the negative. In the synthetic method, we mix the two gases, and unite them as we have before by an electric spark. The blacksmith decom- poses water when he sprinkles it on the hot coals in his forge. The H burns with a blue flame, while the 48 ELEMENTARY CHEMISTKY. O increases the combustion. Thus, in a fire, if the engines throw on too little water, it will be decom- posed, and so add to the fury of the flame. To " set the North River on fire" is only a poetical exagger- ation. The quantity of electricity required to decompose a single grain of water is estimated to be equal to a powerful flash of lightning. The enormous force necessary to tear these two elements from each other shows the wonderful strength of chemical attraction. We thus see, that in a tiny drop of dew there, slum- bers the latent power of a thunderbolt. WATER IN THE ANIMAL WORLD. The abundance of water very forcibly attracts the attention. It con- stitutes four-fifths of our flesh and blood. Man has been facetiously described as 12 Ibs. of solid matter wet up in six pails of water. All plumpness of flesh, all fairness of the cheek, are given by the juices of the system. A few ounces of water causes the phys- ical difference between the round, rosy face of six- teen, and the wrinkled, withered features of three- score and ten. Our tears, poetical as they may seem to us sometimes, are only water and a pinch of salt. To supply the wants of the system each man needs about | of a ton annually. When we pass to lower orders of animals, we find this liquid still more abun- dant. Sunfishes are little more than organized water. Professor Agassiz analyzed one found off the coast of Massachusetts, which weighed 30 Ibs., and ob- tained only J an ounce of dried flesh. Indeed, WATEK. 49 naturalists state that an entire order of animals (aca- lephs), belonging to which are the jelly-fish, medusa, etc., is composed of only ten parts in a thousand of solid matter. WATER IN THE VEGETABLE WORLD. In the vege- table world we find it abundant. Wood is composed of 12 parts charcoal and 10 parts water, with a little mineral matter comprising the ashes. Bread is half water ; and of the potatoes and turnips cooked for our dinner, it comprises 75 parts of one and 90 of the other. The following table shows the proportion in common vegetables, fruits, and meats : Mutton. ., , . .71 Trout .81 Cabbage 92 Beef 74 Apples. . . . .80 Cucumbers . .97 Veal 75 Carrots . . . .83 Watermelons .98 Pork .76 Beets . . .88 In all these instances water is essential to the struc- ture and constitution of the various substances. Eemove it, and they are decomposed into entirely new compounds. WATER IN THE MINERAL WORLD. Here we find a class of bodies in which the water is chemically com- bined in definite proportions. Such are called hy- drates. In the image which the Italian pedler carries through our streets for sale, there is 1 Ib. of HO to every 4 Ibs. of plaster of Paris. One-third of the weight of the soil of our farms is this same liquid. Each pound of strong NO 5 contains 2 J oz. of water, .which, if removed, would destroy the acid 3 50 ELEMENTARY CHEMISTRY. itself. If we expel the water from oil of vitriol, it will lose its acid properties, and we can handle it with impunity. In bodies which are capable of crys- tallizing, it seems only to determine the form and general appearance, and is called " the water of crys- tallization." If we evaporate this from blue vitriol, it will lose its color and become white like flour. A few drops of HO will restore the blue. If we expel it from alum, it will puff up, and the transparent crystals will dry into an incoherent mass. Water of crystallization gives all the transparency to the opal, which else would be only common flint-stone. WATER AS A SOLVENT. Water, having no taste, color, or odor itself, is perfectly adapted to become the universal solvent, receiving instantly the charac- teristics of any substance placed in it. It becomes at pleasure sweet, sour, salt, bitter, nauseous, and even poisonous. Had water any taste, the whole science of cookery would be changed, since each substance would partake of the one universal watery flavor. PURE WATER. Bain-water, caught after the air is thoroughly cleansed by previous showers, and at a distance from the smoke of cities, is the purest nat- ural water known. This is tasteless, yet its insi- pidity makes it seem to us very ill-flavored indeed. We have become so accustomed to the taste of the impurities in hard water, that they have become to us tests of its sweetness and pleasantness. HARD WATER. As water filters down through the WATER. 51 soil into our wells, it dissolves the various mineral matters characteristic of the locality. The most common of these are lime, salt, and magnesia. The former produces a fur or coating on the bottom of our teakettles, if we live in a limestone region. When we put soap in such water, it curdles i. e., it unites with the lime, forming a new or lime soap, which is insoluble in HO. SEA- WATER. Common salt is the most abundant mineral in the ocean. Yet it contains traces of every substance soluble in water, which has been washed into the sea from the surface of the continents during all the ages of the past. Its saline constituents are now in the proportion of about a ^ oz. to a lb., which amount must be slowly increasing, as the water which evaporates from the surface is comparatively pure, containing only a mere trace of a few sub- stances, which give to the sea-breeze its peculiar bracing, tonic influence. In this way, the water of the Salt Lake has become the strongest of brine, nearly one-third of its whole weight consisting of saline matter. This condition would soon disappear if an outlet could be provided. WATER ATMOSPHERE. As the world of waters is inhabited, it has its atmosphere also.* Inasmuch as the HO dilutes the O in part, it does not need so * Fish breathe O through the fine silky filaments of their gills When a fish is drawn out of HO, these dry up, and he is unable to breathe, although he is in a more plentiful atmosphere than he is accustomed to enjoy. 52 ELEMENTAEY CHEMISTRY. much N as the common air. It is accordingly com- posed of ^ O instead of ^. The air so rich in O thus absorbed by the water gives it its life and briskness. If it be expelled by boiling, the water tastes flat and insipid. PARADOXES OF HO. " Cold contracts," is the law of physics ; but as HO cools, it obeys this principle only as far as 39 F. Then it slowly expands, cool- ing down to 32, its freezing point, when its crystals suddenly dart out at angles to each other, and thus, increasing its size -fa, it congeals to ice. By this wise exception, ice is lighter than HO, and so swims on top ; otherwise our rivers would freeze solid, killing the fish and aquatic plants. The longest summer could not melt such an immense mass of ice. But now the blanket that nature kindly weaves over the rivers and ponds keeps their finny inhabitants warm and comfortable till spring ; then she floats it south to melt under a hotter sun. Water is full of contradictory terms. We have hard water and soft water, fresh water and salt water. Water seems the most yielding of substances, yet the swimmer who falls on his face instead of striking head foremost understands the mistake, and we could drive a nail into a solid cube of steel easier than into a hollow one perfectly filled with HO. H is the lightest substance known, and O is an invisible gas ; yet they unite and form a liquid whose weight we have often experienced, and a solid which makes a pavement as hard and unyielding as granite. H burns readily and explodes WATER. 53 most fearfully, O supports combustion brilliantly yet the two combined are used to extinguish fires. USES OF WATER. The uses of water are as poetical as they are practical. Its properties, already dis- cussed in Natural Philosophy, of specific heat, of ex- panding as it solidifies, together with that we have just named of dissolving such a wide range of gases and solids, fit it for a wonderful variety of opera- tions in nature. Its office is not merely to moisten our lips on a hot day, to make a cup of strong tea, to lay the dust in the street, and to sprinkle our gar- dens. It has grander and more profound uses than any of these. Water is the common carrier of crea- tion. It dissolves the elements of the soil, and climbing as sap up through the delicate capillary pump of the plant, furnishes the leaf with the ma- terials of its growth. It flows through the body as blood, floating to every part of the system the life- sustaining O, and the food necessary for repairs and for building up the various parts of the " house we live in." It comes in the clouds as rain, bringing to us the heat of the tropics, and tempering our north- ern climate, while in spring it floats the ice of our rivers and lakes away to warmer seas to be melted. It washes down the mountain side, levelling its lofty summit and bearing mineral matter to fertilize the valley beneath. It propels water-wheels working forges and mills, and thus becomes the grand motive- power of the arts and manufactures. It flows to the sea, bearing on its bosom ships conducting the com- 54 ELEMENTARY CHEMISTRY. inerce of the world. It passes through the arid sands, and the desert forthwith buds and blossoms as the rose. It limits the bounds of fertility, decides the founding of cities, and directs the flow of trade and wealth. CARBON. Symbol, C Equivalent, 8. Carbon is one of the most abundant substances in nature, forming nearly one-half of the entire vege- table kingdom, and being a prominent constituent of limestone, corals, marble, magnesian rocks, etc. We find it in three distinct forms or allotropic con- ditions viz., the diamond, graphite, and amorphous carbon. This last term means without form or crys- tals, and includes gas-carbon, charcoal, lamp-black, coal, coke, peat, soot, bone-black and ivory-black. In each of these various substances C possesses dif- ferent properties ; yet any impurities it may contain seem entirely incidental, and not at all necessary to its new state. PROOF OP THIS ALLOTROPIC STATE. Chemists have changed most of these substances into other allo- tropic forms. Thus, common charcoal has been turned into graphite, mineral coal into gas-carbon, the diamond into coke. All of them, when heated in the open air, unite with the same quantity of O, forming precisely the same compound carbonic acid gas from which the carbon can be obtained again in the form of charcoal. CAKBON. 55 THE DIAMOND is pure carbon crystallized. It is the hardest of all known substances, scratches all other minerals and gems, and can be cut only by its own dust. It is infusible, but will burn at a high temperature. It is found in various parts of the world North Carolina, Georgia, Borneo, and Brazil. The ancient mines of Golconda, in Hindostan, are not now worked. In 1858, Brazil furnished 120,000 carats.* Diamonds are supposed to be of vegetable origin, and to have exuded, at some past time, as gum does now from cherry-trees, and then slowly crystallized. When found, they look like round pebbles, and are covered with a thin crust, which being broken reveals the brilliant gem within. They are of various colors, though often colorless and per- fectly transparent. The latter are most highly esteemed, and, from their resemblance to a drop of clear spring-water, are called diamonds of the " first water." THE DIAMOND is GROUND by means of its 6wn powder. Being fitted to the end of a stick or handle, it is pressed down firmly against the face of a rapidly revolving wheel, covered with diamond-dust and oil. This, by its friction, removes the exposed edge and forms a facet of the The briuiant The r08e ' gem. There are three forms of cutting the brilliant, * A carat is equal to 4 gr. Troy. The term is derived from the name of a bean which, when dried, was formerly used by diamond merchants in India as weights. 58 ELEMENTARY CHEMISTRY. wood, covered over with turf, so as to prevent free access of air. The volatile gases, water, etc., are driven off, and the C left behind. This forms about J of the bulk of the wood and | its weight. Char- coal for gunpowder and for medicinal purposes is pre- pared by heating willow or black alder in iron retorts. Properties. It is the most unchangeable of all the elements, so that even in the charcoal we can trace all the delicate structure of the plant of which it was made. It is insoluble in any liquid. None of the acids, except nitric, corrode it. No alkali will eat it. Neither air nor moisture affects it. Wheat has been found in the ruins of Herculaneum that was charred 1800 years ago, and yet the kernels are as perfect as if grown last harvest. The ground end of posts are rendered durable by charring. Indeed some were dug up not long since in the bed of the Thames which were placed there by the ancient Brit- ons to oppose the passage of Julius Caesar and his army. A cubic inch of fine charcoal has 100 feet of surface, so full is it of minute pores. These absorb gases by capillary attraction to an almost incredible extent. A bit of C will take up 90 times its bulk of ammonia. As the various gases and the O of the air are brought so closely together within its pores, rapid chemical changes are produced, as in the case of platinum black, of which we have already spoken. Fresh provisions are packed in C for long voyages, and hams have been thus kept sweet for years. Foul water filtered through C loses its impurities. Beer CARBON. 59 by this process parts not only with its color but with its bitter taste. Ink is robbed of its value and comes out clear and transparent as water. Deoxydizing Action of C. At a high tempera- ture the appetite of C for O is insatiable. It will take it out in the heat of a furnace from almost the stablest compounds. Upon this fact depends it use in the arts. Nearly all the ores and many of the ele- ments are locked up in the rocks with O, and C is the key expressly made by the Creator for unlocking the treasure-houses of nature for the supply of our wants. By noticing the process of preparing zinc, iron, phos- phorus, etc., we shall see the importance of this property of C. A very pretty illus- tration is shown by placing a few grains of litharge (PbO), or the oxyd of any metal, on a flat piece of Litharge on charcoah charcoal, and directing upon it the flame of a blow- pipe. The metal will immediately appear in little sparkling globules. SOOT is unburnt carbon which passes off from a lamp or fire when there is not enough O present to combine with all the C of the fuel. This, therefore, comes away in flakes, and blackens the chimney of the lamp, or lodges in the chimney of the house. After a time it gathers in sufficient quantity, and we are startled by the cry, " The chimney is on fire !" while with a great roar and flame the soot burns out. This unpleasant occurrence is much more frequent when green wood is used for fuel. The HO of the 60 ELEMENTARY CHEMISTRY. wood absorbs much of the heat of the fire, and so permits the C to pass off unconsumed. LAMPBLACK is obtained by imperfectly burning pitch or tar. The dense cloud of smoke is conducted into a chamber lined with sacking, upon which the soot collects. It is largely used in painting. It is mixed with clay to form black drawing-crayons, and with linseed oil to make printers' ink. Lampblack or charcoal has peculiar properties which fit it for printing. Nothing in nature could supply its place. No matter how finely it is pulverized, it retains its dead-black color. The minutest particle is as black as the largest mass. No chemical agents will change it. It never decays. The paper may moulder we may even burn it, and still, in the ashes, can we trace the form of the printed letter. The ancients used an ink composed of gum-water and lampblack, and man- uscripts have been exhumed from the ruins of Pom- peii^and Herculaneum which are yet perfectly legible. ANIMAL CHARCOAL, or bone-black, is made by burn- ing bones in close vessels. Mixed with oil of vitriol, it forms paste-blacking. Common vinegar filtered through it becomes the colorless white vinegar of the pickle manufacturers. It is largely used by sugar refiners. Brown sugar is dissolved in HO, and the solution filtered through animal charcoal. This re- moves all the impurities which constitute the color- ing matter. The solution is then slowly evaporated in " vacuum pans," and the sugar collects in clear white crystals. CARBON. 61 MINERAL COAL. This was formed in a former period of the world's history, called the Carboniferous Era. At that time the world was pervaded by a genial tropical climate. The air was denser and richer with vegetable food than now. The earth itself was a swamp, moist and hot, in which plants that creep at our feet to-day, or are known only as rushes or grasses, grew to the height of lofty trees, and simple ferns towered into trunks a foot and a half in diameter. These fern-forests resounded with no song of bird or hum of insect ; but a strange and grotesque vegetation flourished with more than tropical luxuriance. In these swamps accumulated a vast deposit of leaves and fallen trunks which, under the water, gradually changed to charcoal. In the process of time the earth settled at various points, and floods poured in, bringing sand, pebbles, clay, and mud, filling up all the spaces between the trees that were standing, and even the hollow trunks them- selves. The pressure of this soil and the internal heat of the earth combined to expel the gases from the vegetable deposits, and convert them into min- eral coal. "Where this process was nearly complete, anthracite coal, and where only partially finished, bituminous coal, was formed. The greater the pres- sure, the harder and purer the carbon produced ; un- less, however, the covering was not sufficiently porous to allow the gases to escape, when bituminous coal was the result. In time this section was elevated again, and another forest flourished, to be in its turn 62 ELEMENTARY CHEMISTRY. converted into coal. Each of these alternate eleva- tions and depressions produced a layer of coal or of soil. In these beds of coal we now find the trunks of trees, the outlines of trailing vines, the stems and leaves of plants as perfectly preserved as in a her- barium, so that, to the botanist, the flora of the Car- boniferous era is as complete as that of our own. COKE is the refuse of gas-works, obtained by dis- tilling off all the water, tar, and volatile gases from bituminous coal. It is burned in locomotives, blast- furnaces, etc. PEAT is an accumulation of half-decomposed veg- etable matter in swampy places. It is produced mainly by a kind of moss which gradually dies below as it grows above, and thus forms beds of great thick- ness. Sometimes, however, plants may grow in the form of a turf, and decay, thus collecting a vast amount of vegetable debris. This gradually undergoes a change, and becomes a brownish black substance, loose and friable in its texture, resembling coal, but, unlike it, containing 20 to 30 per cent, of O. These peat-beds are of vast extent. One-tenth of Ireland is covered by them. One, near the mouth of the River Loire, is said to be fifty leagues in circumfer- ence. In Massachusetts and in New York peat is becoming of commercial value, and is used as a fuel in large quantities. For this purpose it is cut out in square blocks and dried in the sun. In many beds it is first finely pulverized, then pressed into a very compact form like brick. CARBON. 63 MUCK is an impure kind of peat, not so fully car- bonized, though the term is frequently applied to any black swampy soil which contains a large quantity of decaying vegetable matter. Like charcoal, it ab- sorbs moisture and gases, and is therefore used as a fertilizer. VARIOUS FORMS AND USES OF CARBON. We have seen in what contrary forms carbon presents itself. It is soft enough for the pencil-sketch, and hard enough for the glazier's use. Black and opaque, it expresses thought on the printed page : clear and brilliant, it gleams and flashes in the diadem of a king. In lampblack it frequently takes fire spon- taneously; in graphite, it resists the heat of the fiercest flame; in the diamond, it is an insulator, while in charcoal, it is so perfect a conductor of elec- tricity, that it is packed about the foot of lightning- rods to complete the connection with the earth. We burn it in our lamps, and it gives us light ; we burn it in our stoves, and it gives us heat ; we burn it in our engines, and it gives us power ; we burn it in our bodies, and it gives us strength. As fuel, it readily unites with O, yet we spread it as stove-polish on our ironware to keep the metal from rusting. It gives firmness to the tree and consistency to our fiesh. It is the valuable element of all fuel, burning oils, and gases. Thus it supplies our wants in the most diverse manner, illustrating in every 'phase the forethought of that Being who fitted up this world as a ho ne for his children. Infinite Wisdom alone would 64 ELEMENTAKY CHEMISTBT. have stored up such supplies of fuel and light, and hidden them far under the earth away from all dan- ger of accidental combustion, or anticipated all the requirements alike of luxury and the arts. CARBONIC ACID. Symbol, C02 Equivalent, 22 ...-Specific Gravity, 1.52. Sources. It is found combined with lime, as in lime- stone, marble, chalk, and also in a large class of salts, known as the carbonates, forming nearly one-half of their weight, and almost one-seventh of the crust of the earth. It comprises y^g- part of the atmosphere. It is produced throughout nature in immense quan- tities. Wherever C burns, in fires, lights, decay, fermentation, volcanoes in a word, in all those va- rious forms of combustion of which we spoke under the subject of O, where that gas unites with C, car- bonic gas is the result. Each adult exhales about 140 gallons per day. Each bushel of charcoal, in burning, produces 2500 gallons. Preparation. For experimental purposes it is pre- pared by pouring HC1 (hydrochloric acid) on marble or chalk. The reaction is as follows : HC1 4- CaO.C0 2 CaCl + C0 2 The H of the hydrochloric acid unites with the O of the lime (CaO), forming HO. The 01 of the acid CARBONIC ACID. 65 combines with the Ca of the lime, forming chloride of calcium, while the C0 2 is driven off. It may be Making carbonic acid. collected in bottles by displacement, or as represented in the cut. Pouring CO 9 down-hill. 66 ELEMENTAEY CHEMISTRY. Test. Its test is clear lime-water. If we expose a saucer of lime-water to the air, its surface is soon covered with a thin pellicle of carbonate of lime, thus showing that there is CO 2 in the atmosphere ; or if we breathe by means of a tube through lime-water, the solution will become turbid and milky, thus prov- ing the presence of CO 2 in our breath : by breathing through the liquid a little longer it will become clear, as the carbonate of lime will dissolve in an excess of CO 2 . Properties. It is a colorless, odorless, transparent gas, with a slightly acid taste. It is a non-supporter of combustion, will run down an inclined plane, and can be poured from one dish to another, and dipped up with a bucket like water, or be weighed in a pair of scales like lead. Example : The accompanying Weighing CO 3 . cut shows a very neat way of illustrating several of these properties. For weighing, the C0 2 may be contained in a large paper box or bag, such as is used by grocers. CARBONIC ACID. 67 Poisoning by C0 2 - This gas is fatal to life. When largely diluted it acts as a narcotic, producing lan- guor, and finally insensibility and death. It accu- mulates in wells and cellars, and many persons have been poisoned by descending into such places incau- tiously. The test of lowering a lighted candle should always be employed. If that is extinguished, your life would be in danger of " go- ing out" in the same way, should you descend. The gas may be dipped out like water, or the well may be Can o d fco 2 . jar purified by lowering pans of slacked lime, or lighted coals A candle ta c a ' which, when cool, will absorb the noxious gas. The coals may be reignited, and lowered repeatedly until the result is reached. A well, in which a candle would not burn within 26 feet of the bottom, was thus purified in a single afternoon. Persons have been poisoned by burning charcoal in an open fur- nace in a closed room. In Prance, it is not unusual to commit suicide in this manner. The antidote is to bring the sufferer into the fresh air, and dash cold water upon his face. In the celebrated Grotto dd Cane, in Italy, the gas accumulates near the floor, so that a man living near amuses visitors, for a small fee, by leading his dog into the cave. He experi- ences no ill effects himself, but the dog soon falls senseless, A dash of cold water revives him, and 68 ELEMENTARY CHEMISTRY. he is ready to pick up his bone and enjoy the reward of his scientific experiment. The celebrated Upas tree of Java seems not to be altogether fabulous. The poison is not derived from the tree itself ; but is due to the fact that it is located in a deep valley about a half-mile in circumference, in which CO 2 is evolved in quantities sufficient to contaminate the entire atmosphere. The valley is said to be strewn with the bones of animals and birds which have strayed into this gaseous lake. CO 2, in Mines. Miners call CO 2 clioke-damp. It is produced by the explosion (Afire-damp (light car- buretted hydrogen) which accumulates in deep mines, and burns with a shock like gunpowder, forming dense volumes of CO 2 , which instantly destroys the lives of all who may have escaped the flames of the explosion. Where CO 2 alone is found, it is not considered as dan- gerous as the fire-damp, since it will not burn, and it is said that miners will even venture " where the air is so foul that the candles go out, and are then relighted from the flame on the wick by swinging them quickly through the air, when they burn a little while and then go out, and are relighted in the same way." CO 2 has been used for the purpose of extinguishing fires in coal-mines. In one case an English mine had burned for 20 years, consuming a seam of coal over a space of 26 acres, defying all attempts to quench it. 8,000,000 cubic feet of CO 2 were poured into it day and night for three weeks, when the mine was cooled with water ; and at last, at the close of CARBONIC AGED. 69 the month, the mine was ready for labor to be re- sumed. Absorption of C0 2 ~by Liquids. Water dissolves its own volume of CO 2 under the ordinary pressure of the atmosphere; but with increased pressure, it will absorb a much greater amount. " Soda water" is improperly named, as it contains no soda, but is simply water saturated with CO 2 in a copper receiver strong enough to resist the pressure of 10 or 12 at- mospheres. This gas gives the HO a pleasant, pun- gent, and slightly acid taste, and by its escape, when exposed to the air, produces a brisk effervescence. In beer, ginger-pop, cider, wine, etc., the CO 2 is pro- duced by the fermentation going on within. The gas escapes rapidly through cider and wine, and so pro- duces only a sparkling ; while in a thick, viscid liquid, like beer, the bubbles are partly confined, and so cause it to foam and froth. In canned fruits, catsup, etc., the souring of the vegetables produces CO 2 , which sometimes di ives out the cork or bursts the bottles with a loud report, scattering the contents far and wide. Liquid CO-2. By a pressure of 40 atmospheres, at a temperature of 32, CO 2 becomes a colorless liquid, very much like water. When this liquid is brought out into the air, it evaporates so rapidly that a por- tion is frozen into a snowy solid which burns the flesh like a red-hot iron. By means of liquid CO 2 , which has a temperature of 150 F., mercury can be frozen even in a red-hot crucible. Mixed with ether, 68 ELEMENTARY CHEMISTRY. he is ready to pick up his bone and enjoy the reward of his scientific experiment. The celebrated Upas tree of Java seems not to be altogether fabulous. The poison is not derived from the tree itself ; but is due to the fact that it is located in a deep valley about a half-mile in circumference, in which CO 2 is evolved in quantities sufficient to contaminate the entire atmosphere. The valley is said to be strewn with the bones of animals and birds which have strayed into this gaseous lake. (70 2 in Mines. Miners call C0 2 choke-damp. It is produced by the explosion of fire-damp (light car- buretted hydrogen) which accumulates in deep mines, and burns with a shock like gunpowder, forming dense volumes of CO 2 , which instantly destroys the lives of all who may have escaped the flames of the explosion. Where CO 2 alone is found, it is not considered as dan- gerous as the fire-damp, since it will not burn, and it is said that miners will even venture " where the air is so foul that the candles go out, and are then relighted from the flame on the wick by swinging them quickly through the air, when they burn a little while and then go out, and are relighted in the same way." CO 2 has been used for the purpose of extinguishing fires in coal-mines. In one case an English mine had burned for 20 years, consuming a seam of coal over a space of 26 acres, defying all attempts to quench it. 8,000,000 cubic feet of CO 2 were poured into it day and night for three weeks, when the mine was cooled with water ; and at last, at the close of CARBONIC ACID. 69 the month, the mine was ready for labor to be re- sumed. Absorption of C0 2 by Liquids. Water dissolves its own volume of CO 2 under the ordinary pressure of the atmosphere; but with increased pressure, it will absorb a much greater amount. " Soda water" is improperly named, as it contains no soda, but is simply water saturated with CO 2 in a copper receiver strong enough to resist the pressure of 10 or 12 at- mospheres. This gas gives the HO a pleasant, pun- gent, and slightly acid taste, and by its escape, when exposed to the air, produces a brisk effervescence. In beer, ginger-pop, cider, wine, etc., the CO 2 is pro- duced by the fermentation going on within. The gas escapes rapidly through cider and wine, and so pro- duces only a sparkling ; while in a thick, viscid liquid, like beer, the bubbles are partly confined, and so cause it to foam and froth. In canned fruits, catsup, etc., the souring of the vegetables produces CO 2 , which sometimes diives out the cork or bursts the bottles with a loud report, scattering the contents far and wide. Liquid CO i. By a pressure of 40 atmospheres, at a temperature of 32, CO 2 becomes a colorless liquid, very much like water. When this liquid is brought out into the air, it evaporates so rapidly that a por- tion is frozen into a snowy solid which burns the flesh like a red-hot iron. By means oi liquid CO 2 , which has a temperature of 150 F., mercury can'be frozen even in a red-hot crucible. Mixed with ether, 70 ELEMENTARY CHEMISTRY. and evaporated under the exhausted receiver of an air-pump, Professor Faraday obtained a cold of 166 below zero. Ventilation. The relation of carbonic acid to life is most important, and cannot be too often dwelt upon. We exhale constantly this poisonous gas, each person contaminating at least 10 cubic feet of air per minute. If means are not provided to furnish us fresh air constantly, we are compelled to re-breathe that which our lungs have just expelled. The lan- guor, the sleepiness we feel in a crowded assembly, is the natural effect of this narcotic poison. The idea of drinking in at every breath the exhalations that load the atmosphere of a crowded, promiscuous assembly, is disgusting as it is noxious. We shun impurity in every form; we dislike to wear the clothes of another, or to eat from the same dish; we shrink from contact with the filthy, and yet sit- ting in the same room inhale their poisonous breath. Health and cleanliness alike require that we should carefully ventilate all public buildings, our school- rooms, and our sleeping-apartments. Fresh air and good water are the cheapest luxuries of life, and alas ! too commonly the rarest. Singular Truth. It is a fact, as poetical as it is characteristic, that when the CO 2 comes forth from the lungs it is poisonous, fully charged with the seeds of disease, so that if we should re-breathe it, death would inevitably ensue ; yet as it passes out it pro- duces all the tones of the human voice, all songs, and CARBONIC ACID. 71 prayers, and social conversation. Thus the gross and deadly is by a divine simplicity made refined and spiritual, and caused to minister to our highest happiness and welfare. CARBONIC OxYD.(CO). This is a colorless, almost odorless gas. It burns with a ' pale, blue flame, ab- sorbing an atom of O from the air, and becoming CO 2 . It is seen thus burning in our coal-stoves, and at the top of tall furnace-chimneys. It is caused by an insufficient supply of O. It is a deadly poison, and escaping from coal-fires in a close room has often produced death. The offensive odor which conies out on opening the door of our coal-stoves is caused by the compounds of sulphur mixed with the CO. LIGHT CARBURETTED HYDROGEN (C 2 H 4 ). This is the gas we have already spoken of under CO 2 , as the dreaded fire-damp of miners. It is colorless, taste- less, odorless, and burns with a yellowish flame. It is formed in swamps and low marshy places by the decomposition of vegetable matter, and on stirring the mud be- neath, will be seen bub- bling up through the w r ater. It rises from Marsh-gas. the earth in great quantities at many places. At Fredonia, N. Y., it is collected and used in lighting the village. At Kanawha, Va., it is employed as fuel for evaporating the brine in the manufacture of salt. 72 ELEMENTARY CHEMISTRY. In the oil-wells of Pennsylvania, it frequently bursts forth with explosive violence, throwing the oil high into the air. HEAVY CARBURETTED HYDROGEN (C 4 H 4 ). Olefiant Gas. This is a colorless gas, with a sweet, pleasant odor, and burns with a clear white light. ILLUMINATING GAS consists principally of the two gases just named. The proportion of the latter, or olefiant gas, which gives the clearness and whiteness to the flame, determines its value. It is made by heating bituminous coal in large iron retorts until coke only is left, and all the volatile constituents are driven off.* These are very numerous. Among them are coal-tar, ammonia, carbonic acid, carbonic oxyd, nitrogen, compounds of sulphur, light and heavy carburetted hydrogen. This mixture is first cooled in the condenser, which is a series of iron tubes surrounded by cold water, in which the coal- tar is deposited, with the ammoniacal liquids. Then it is sprinkled with a spray of water, which takes out all the ammonia, and last of all passed through milk of lime, which absorbs the carbonic acid. The re- maining gases form the mixture we call " gas." This is then collected in the gasometer, the weight of which forces it through all the little gas-pipes, and up to every jet in the city. Its unpleasant odor, and the danger resulting from its escape in our rooms, are the same we have just mentioned in coal fires. CYANOGEN (Cy, NC 2 ). If we mix hides, horns, etc., * A ton of Cannel coal will yield 15,000 feet of gas. COMBUSTION. 73 with carbonate of potash and iron filings, and heat them in a close vessel, the N and C of these animal substances in their nascent state will combine, form- ing cyanogen. This unites with the iron and potas- sium, forming the beautiful yellow crystals of ferro- cyanide of potassium, or so-called yellow prussiate of potash. The compounds of cyanogen are named cyanides, and are all made from this salt. HYDROCYANIC ACID (HCy). Prussic acid, as it is commonly called, is a most fearful poison. A single drop on the tongue of a large dog is said to produce instant death. Ammonia, cautiously inhaled, is its antidote. Its bitter flavor is detected in peach blossoms, the kernels of plums or peaches, bitter almonds, and the leaves of wild cherry. FULMINIC ACID. This compound of Cy is known only as combined with the various metals forming fulminates, which are fearfully explosive. (The term fulminate is from the Latin fulmen, a thun- derbolt.) Fulminating mercury was used to fill the bombs with which the life of Napoleon III. was attempted in 1858. It is employed in making gun- caps. A drop of gum is first put in the bottom of the cap, over which is sprinkled a little fulminating mercury, and this is sometimes covered with varnish to protect it from the moisture. COMBUSTION. Combustion, in its popular sense, is the union of a substance with O, and includes all the various forms 4 74 ELEMENTAEY CHEMISTRY. of oxydation we named when treating of that gas. The amount of heat depends upon the quantity of O which enters into combination. Example : HO = 9. Hence, in 9 Ibs. of HO there are 8 Ibs. of O, and 1 Ib. of H. On the other hand, CO 2 = 22. Hence, in 22 Ibs. of carbonic acid there are 6 Ibs. of C and 16 of O ; lib. of C unites with 2| Ibs. of O. Therefore, H combines with three times as much O as C does, and so gives off three times as much heat. The intensity of the heat de- pends upon the rapidity with which the fuel unites with O. So we open the draft, or blow a fire, to fur- nish this active element of the air in greater abun- dance. The Igniting Point. Although O unites at all temperatures, yet combustion, in its popular sense, does not commence until the heat of the combustible is raised to a certain point, when we say " it has caught fire." The burning point of any substance is the temperature at which it bursts into quick com- bustion. We elevate the heat of a small portion to the point of rapid union with O, and that part in burning will give off heat enough to support the combustion of the rest. Example : In making a fire, we take a substance for kindling which unites with O at a low temperature, as paper or shavings, with which we obtain heat enough to start the combustion of something that requires a higher temperature, as chips or pine sticks, and thus gradually increase the degree of heat until we reach the igniting point of COMBUSTION. 75 coal or wood. If we pour on much coal when the fire is low, we will put it out, because the fresh fuel lowers the heat below the point of union with O, which is about 1000. CHEMISTBY OF A FIBE. All our fuel and lights, such as wood, coal, oil, tallow, etc., consist mainly of C and H, and are, therefore, called hydrocarbons. In burning, they unite with the O of the air, forming HO and CO 2 . These both pass off, the one as a vapor, the other as a gas. In a long stove-pipe, the HO is sometimes condensed, and drips down, bringing soot upon our carpets. Ashes comprise the mineral matter contained in the fuel, united with some of the CO 2 produced in the fire. When we first put fuel in the stove, the H is liberated with some C, in the form of carburetted hydrogen gas. This burns with a flame. Then, the volatile H having passed off, we have left the C, which burns as a coal merely. In maple there is much more C than in pine, so it forms a good " bed of coals." In the burning of fuel there is no annihilation ; but the HO, CO 2 , and the ashes, weigh as much as the wood and the O that combined with it. No matter how rapidly the fire burns, in the blaze of the fiercest conflagration, the elements unite in exact chemical equivalents. Carbon is most wisely fitted for fuel, since the pro- duct of its combustion is a gas. Were it not so, our fires would be choked, and before each supply of fresh fuel we would be compelled to remove the ashes that filled the stove. In the case of a 76 ELEMENTARY CHEMISTEY. candle it would be still more annoying, as the solid product would fall around our rooms in an acid shower that would corrode every thing it touched. Still another property is the infusibility of carbon. Did it melt like zinc or lead on the application of heat, how quickly in a hot fire would the coal and wood melt, and run down through the grate and out upon the floor in a liquid mass ! These properties, together with its abundance, exactly adapt it to our use. CHEMISTRY OF A CANDLE. Flame is burning gas. A candle is a small " gas-works," and its flame is the same as that of a " gas-burner." First we have a little cupful of tallow melted by the heat of the fire above. The ascending currents of cool air which supply the light with O also keep the sides of the cup hard, unless the wind blows the flame downward, when the banks break, there is a crevasse, and our candle runs down. Next, the melted tallow is carried by capillary attraction up the small tubes of the wick into the flame. There it is turned into gas by the heat. Flame is always hollow, and at the centre, Form of flame. ., i j i i < n T < near the wick, is the gas just formed. If a match be placed across a flame, it will burn off at each side in the ring of the flame, while the centre will be unblackened. The gas may be conducted out of the flame by a small pipe, and burned at a little distance from the candle. The flame is hollow COMBUSTION. 77 because there is no O at the centre. The gas floats outward from the wick. It comes in contact with the O of the air, and the H, requiring least heat to unite, burns first, forming HO. This produces heat enough to make the tiny particles of C, floating around in the flame of burning H, white-hot. They each send out a delicate wave of light, and passing on to the outer part, where there is more O, burn, forming CO 2 . The flame is blue at the bottom, because there is so much O at that point that the H and C burn together, and so give little light. The HO may be condensed on any cold sur- face. The CO 2 may be tested by passing the invisible smoke of a candle through lime-water. The wick of a candle does not burn because of the lack of O at the centre. It, however, is charred, as all the volatile gas is driven off by the heat. If a portion falls over to the outer part, where there is O, it burns as a coal. If we blow out a candle quickly, we can see the gas passing off, and can relight the candle with an ignited match held at some distance from the wick. The tapering form of the flame is due to the currents of air that sweep up from all sides toward it. The candle must be snuffed, because the long wick would cool the blaze below the igniting point of C and O, and the C would pass off unconsumed. A draught of air, or any cold substance thrust into the flame, Match in flame. 78 ELEMENTAEY CHEMISTKY. Water In a flame. produces the same result, and deposits the C as soot. Plaited wicks are sometimes used, which, being thin, fall over to the outside and burn, requir- ing no snuffing. CHEMISTRY OF A LAMP. A chimney confines the hot air and makes a draught of O through the flame. A flat wick is used, as it pre- sents more surface to the ac- tion of the O. Argand lamps are made with a hollow wick, so as to admit O into the centre of the blaze. The film which gathers on a chimney when we first light a lamp, is the HO produced in the flame, con- densed on the cold glass. A pint of oil forms a full pint of HO. Spirits of turpentine, tar, pine-wood, etc., contain an excess of C, and not enough H to heat it to the point of union with O. These, therefore, produce clouds of soot. Alcohol contains an excess of H and little C, hence it gives off great heat and but little light. Davy's Safety Lamp, used by miners, consists of an ordinary oil-lamp, surrounded by a cylin- der of fine wire-gauze. Even if the flame of the lamp is thrown against the outside, or inflam- COMBUSTION. 79 mable gases from the mine come into the inside, the wire conducts off the heat, and reduces it below the point of union with O, so no flame can pass through, and no gas on the outside ignite. Through carelessness fearful acci- dents have occurred, even since this lamp has been used. Miners become extremely negligent, and an account is given of an explosion, in which . 1in i-iiT Wire-gauze in flame. about a hundred persons were killed, caused by a lamp being hung on a nail by a hole broken through the wire-gauze. EXTINGUISHING FIRES. Blowing on a candle or lamp extinguishes it, because it lowers the heat of the flame below the point of union of C with O. Fires are put out by HO partly for the same reason, and also because it envelops the wood and shuts off the air. If a person's clothes take fire, the best pos- sible remedy is to wrap him in a blanket, carpet, coat, or even in his own garments. This smothers the fire, by shutting out the O of the air. Great care should be taken in a fire not to open the doors or windows, so as to cause a draught of air. The entire building may burst into a blaze, when the fire might have been confined for want of O, and so easily extinguished. SPONTANEOUS COMBUSTION. Sometimes chemical changes take place in combustible substances, whereby heat enough is generated to cause ignition. Lime occasionally absorbs HO, so as to set fire to 80 ELEMENTARY CHEMISTBY. wood in contact with it. Fresh-burned charcoal has the power of absorbing gases in its pores so vigorously as to become ignited. Heaps of coal often take fire from the iron pyrites contained in them being decomposed by the moisture of the air. The waste cotton used in mills for wiping oil from the machinery, is thrown into large heaps, and ab- sorbs O from the air so rapidly that it often bursts into a blaze. Instances have been given of the hu- man body itself taking fire spontaneously. Jt hap- pens most generally in the case of intemperate persons. In these instances the fire was not easily subdued nor communicated to other substances, the body having even burned to ashes while the garments were unconsumed. OX-HYDBOGEN BLOW-PIPE.* In the Compound Blow-pipe a jet of O is introduced into the centre of a jet of burning H, producing a solid flame. Inasmuch also as H unites with so much O, an im- mense heat is developed. A watch-spring will burn in it with a shower of sparks. Platinum, the most infusible of metals, requiring a temperature of 4591, or over twenty times that of boiling water, readily melts. In the common hollow flame, as we have seen, the little * See Frontispiece. COMBUSTION. 81 particles of solid C, heated by the burning H, produce the light. As there is no solid body in the Blow- pipe flame, it is scarcely luminous. If, however, we insert in it a bit of lime, a most dazzling light is pro- duced. This is called the " Drum- mond," "Lime," or "Calcium" Light, and has been seen at a dis- tance of one hundred and eight miles in broad sunlight. Mow-pipe. In the common blow- pipe, used by jewellers, a current of O from the lungs is thrown into the centre of an alcohol blaze. It is thus rendered solid and its heat cr mmon greatly increased. Near the extreme point of the flame the unconsumed gases are very hot, and com- bine readily with the O of any substance in- serted into the flame at that part, which is therefore, called the " reducing flame." Just Reducing liame. at the point of the flame, the O thrown from the lungs is highly heated, and is ready to combine with any substance, and is therefore called the " Oxydizing flame" Example : Hold a copper cent in the flame of an alcohol lamp. 4* 82 ELEMENTARY CHEMISTRY. In the " reducing flame" its rust or oxyd of copper will be all cleaned off, and the cent will shine as brightly as if just from the mint. In the " oxydizing flame" the various oxyds of cop- per will be formed over the surface, and so the most _ ,. . _ beautiful play of colors Oxydizm- flame. r J will flash from side to side as we move the cent from one part to the other. THE ATMOSPHERE. The " air we breathe" consists of N, O, CO 2 , and watery vapor. The first composes!, the second-^, the third yoV^ an ^ *he ^ as ^ a variable proportion. The N and O form so large a part, that they are con- sidered in ordinary calculation to compose the whole atmosphere. A very clear idea of the proportion of these several constituents may be formed by conceiv- ing the air, not as now dense near the surface of the earth, and gradually becoming rarified as we ascend to is extreme limit of 50 miles, but of a density throughout equal to that which it now possesses near the earth. The atmosphere would then be but about five miles high. The vapor would form a sheet of HO over the ground five inches deep, next the CO 2 a layer of 13 feet, then the N a layer of one mile, and last of all, the O a layer of four miles. ( Graham.) In this arrangement we have supposed the gases to be placed in the order of their specific gravity. The THE ATMOSPHERE. 83 atmosphere is not thus composed in fact, the various gases being equally mingled throughout, in accord- ance with a principle called the " Law of the Diffu- sion of Gases." If we throw a piece of lead into a brook, it will settle instantly to the bottom by the law of gravitation, and remain there forever by the law of inertia. But if we throw out into the atmos- phere a quantity of CO 2 , it sinks for an instant, then immediately begins to mingle with the surrounding air, and is soon entirely dissipated. Example : If we invert an open-mouthed bottle full of H over another full of CO 2 , in a few hours the H, light as it is, will have crawled down into the lower jar ; and the CO 2 , heavy as it is, will have crawled up into the upper jar ; and the gases will be found equally mixed. By this law the proportion of the elements of the at- mosphere is the same everywhere, and has not varied within historic times. Samples have been analyzed from every conceivable place, from polar and torrid regions, from prairies and mountain-tops, from bal- loons and mines, and even from bottles-full sealed up in the ruins of Herculaneum, and the result is the same. These gases do not form a chemical compound, but a mere mechanical mixture, and they are as distinct in the air as so many grains of wheat and corn mingled in a measure. Each of these has its separate use and mission. The action of O and N we have already seen. Uses of CO- 2 . This bears the same relation to vegetable that does to animal life. The leaf-*-the 84 ELEMENTABY CHEMISTRY. plant-lungs through its million of little stommata, or mouths, drinks in the CO 2 . In that minute leaf- laboratory, by the action of the sunbeam, the CO 2 is decomposed, the C being applied to build up the plant, and the O returned to the air for our use. Plants breathe out O as we breathe out CO 2 . We furnish vegetables with air for their use, and they in turn supply us. There is thus a mutual dependence between the animal and the vegetable world. Each relies upon the other. Deprived of plants we would soon exhaust the O from the air, supply its place with CO 2 , and die; while they, removed from us, would soon exhaust the CO 2 , and die as certainly. "We poison the air while they purify it. Each tiny leaf and spire of grass is thus imbibing our foul breath, and returning it to us pure and fresh.* This interchange of office is so exactly balanced, that, as we have seen, the proportion of CO 2 and of O never varies. " Two hundred million tons of coal are now annually burned, producing six hundred million tons * In connection with this subject it is well to notice that the current idea, that plants exhale CO 2 at night, is now known to be erroneous. They purify the air while the sunlight shines upon them, and hi darkness are at rest. Plants in a room are, therefore, healthy, unless they are of such varieties as emit a poisonous odor. Certainly the freshness and cheeriness given to an apartment by a stand of flowers, or even a few pots in a win- dow-bench, must delight all ; while the refining influence of the beautiful in nature would suggest the propriety of adorning our dwellings in this simple manner, did not chemistry teach its prac- tical utility as a mode of purifying the air. THE ATMOSPHERE. 85 of CO 2 . A century ago, hardly a fraction of that amount was burned, yet this enormous aggregate has not changed the proportion in the least." ( Youmans.) Use of Watery Vapor. We have already seen the uses of HO. As vapor, it is everywhere present and ready to supply the wants of animals and plants. Were the air dry, our flesh would shrivel into that of a mummy, and leaves would wither as they do in an African simoom. Hivers and streams flow to the ocean ; yet all their fountains are fed by the currents that move in the air above us. HO rises in the air as vapor, flows on to colder regions, falls as rain, dew, snow, or hail, and then working as it goes what- ever it finds to do, moistening a plant or turning a water-wheel, it finds its way back to the ocean. Thus Niagara itself must first have risen to the clouds as vapor before it can fall as a cataract. PERMANENCE OF THE ATMOSPHERE. Did the ele- ments readily unite to form nitric acid, instead of, as now, with great difficulty, and only in a thunder- storm, we would be constantly exposed to a shower of this corrosive acid that would be destructive to all vegetation, clothing, and even our bodies them- selves. O and N have never been solidified or lique- fied by the severest cold or pressure, while CO 2 re- quires a force that is never reached in nature. Watery vapor, on the contrary, is deposited as dew or rain by a slight change of temperature ; this is necessary to supply the wants of vegetation and life. But were the same true of the other constituents, 86 ELEMENTARY CHEMISTEY. they would come raining down upon us in most dis- astrous showers; and in winter we would be com- pelled to melt what air we should need, and carry a supply with us constantly. Life itself would be un- endurable under such circumstances. Again, the permanence of the air produces all the uniformity of sound. Were the proportions of the atmosphere to change, all "familiar voices" would become strange and uncouth to us, while the harmonies of music would shock us with unwonted discord. If, by some means, the air of a concert-room could be changed to H, for instance, the bass voices would become ir- resistibly comic and shrill, while the tenor would emulate railway whistles. It is pleasant to notice how each element of the air is adapted for a special work, and all fitted to the present order of nature. THE HALOIDS. Chlorine Symb-, Clj Equiv-, 35-5; Spec- Grav-, 2-47 Iodine " 1} " 126-8; " 2-47 Bromine-... Brj " -80; " (at 30), 3-18 Fluorine-.-. " Fl j " -19} " 1-31 These four elements are closely allied, and form a class of compounds known as the haloid salts, from hals, salt, because they resemble common salt. CHLORINE is named from its green color. It is chiefly found in common salt, of which it forms 60 per cent., and is made by moderately heating it with black oxyd of manganese, sulphuric acid, and water. This mixture liberates the gas in great quantities. CHLORINE. 87 It is heavier than common air, and so may be col- lected by displacement. Making Chlorine. Properties. It has a greenish-yellow color, and a peculiarly disagreeable odor. It produces a suffo- cating cough, which can be relieved by breathing ammonia or ether. Arsenic, antimony, Dutch gold- leaf, phosphorus, etc., combine with it so rapidly as to inflame ; powdered antimony producing a shower of brilliant sparks when slowly dropped into a jar of Cl. Cold water absorbs about twice its volume of the gas, which soon turns to hydro- chloric acid (HC1) in the sunlight. It has such a powerful affinity for H, that it will even attract it out of a moist organic body, and form HC1. It acts thus upon turpen- tine, depositing its C in great flakes of soot. It discharges the color of indigo, ink, wine, etc., almost instantaneously. It has no effect on printers' ink, as that contains no H. inC1 - 88 ELEMENTARY CHEMISTRY. HYDROCHLORIC ACID (HC1) Muriatic Acid. When Cl and H are mixed and ex- posed to the direct sunlight they unite with an explosion. In the arts, HC1 is prepared from sulphuric acid and com- mon salt. NaCl-hSO 3 .HO Making HC1. NaO . S0 3 + HC1 Properties. It is an irrespirable, irritating, acid gas, with an intense attraction for HO, which causes it to produce white fumes in the air. Water absorbs 480 times its bulk, forming the liquid known as "Muriatic Acid.'" It unites with the metals, and forms chlorides. When pure it is colorless, but has ordinarily a yellow tinge, due to various impurities. Its tests are ammonia, with which it forms a white cloud of sal-ammoniac fumes, and nitrate of silver, from which it precipitates chloride of silver. With NO 5 it forms aqua-regia, or royal water, so named because it dissolves gold, the " king of the metals." It sets free chlorine, which, in its nascent state, at- tacks the gold and combines with it. CHLORIDE OF LIME (Bleaching Powder}. This is prepared by passing a current of Cl over pans of CHLORINE. 89 fresh slacked lime. It is much used in bleaching and as a disinfectant. Bleaching. In domestic bleaching the cloth is first boiled with strong soap, to dissolve all the grease and wax, and then laid upon the grass, being fre- quently wet to hasten the action of the air and sun. The dew seems to have a peculiar influence, while the corrosive ozone of the atmosphere doubtless aids in the process. The H of the coloring matter unites with the O of the air or dew, forming HO, and thus destroying the coloring compound. This was essen- tially the process long pursued in Holland, where all linens were formerly carried for bleaching : hence the term " Holland linen," still in use. The HO about Haarlem was thought to have peculiar prop- erties, and no other could compete with it. Cloths sent there were kept the entire summer, and were returned in the fall. Later a similar plan was adopted in England. But the vast extent of grass- land required, the time occupied, and the temptation to theft, made the process extremely tedious and expensive. The statute laws of that time abound in penalties for cloth stealing. It is estimated that all the men, women, and children in the world could not, by the old way, bleach all the cloth that is now used. At present the cloth is well washed, and boiled in water with strong alkalies, to remove the grease, by the decomposing action of a powerful galvanic battery. By passing the current through potassa (KO), the K went to the negative pole, and the O to the positive. In the same manner he separated the metals sodium, barium, strontium, and calcium. This discovery constituted a most im- portant epoch in chemistry. K is found abundantly in nature in the various rocks which, by their decom- POTASSIUM. 105 position, furnish it to the plants, from whence we obtain our entire supply. Properties. It is a silvery-white metal, soft like wax, and light enough to float like cork. Its affinity for O is so great, that it is always kept under the surface of naphtha, which contains no O. K, when thrown on HO, decomposes it, unites with its O, forming KG, and sets free the H. The heat developed is so great, that the H catches fire and burns With SOme Volatilized K, which Potassium on water. tinges the flame with a beautiful purple tint. If the HO be first colored with red litmus, it will become blue by the alkali (KO) formed. POTASSA (KO) Potash. This is a grayish-white solid, made from KO.CO 2 by the action of lime. It is the most powerful alkali. It neutralizes the acids, and turns red litmus to blue. It is used to cauterize the flesh, and is hence commonly called " caustic potash." It dissolves the cuticle of the finger which touches it, and so has an unctuous feel, as we see in strong soap. It unites with grease, forming soap, and is extensively used for that purpose. Its affinity for HO is so great, that it is never known except as a hydrate (KO . HO). It also absorbs CO 2 from the air, and must be kept in close-stoppered bottles. It is a corrosive, deadly poison. Its test is bichloride of platinum, forming a yellow precipitate from a so- lution. CARBONATE OF POTASH (KO.C0 2 ) Pearlash. Pot- 5* 106 ELEMENTARY CHEMISTRY. ash is contained in plants, combined with various acids, such as tartaric, malic, oxalic, etc. When the wood is burned, the CO 2 of the fire drives off these acids, and combines with the KO, forming KO.CO 2 . The ashes are then leached, and the lye which is formed is evaporated until the KO.CO 2 crystallizes. Birch gives the purest potash, while the leaves fur- nish 25 times as much as the heart of a tree. Where wood is abundant, immense quantities are burned solely for the ashes. Saleratus is a bicarbonate of potash (KO.2CO 2 ), and is formed by passing a current of C0 2 through the carbonate. NITRATE or POTASH (KO.NO 5 ) Saltpetre : Nitre. This salt is found abundantly in Egypt and the East Indies, mixed with the soil. It is obtained thence by leaching. It is formed artificially by piling up great heaps of mortar, refuse of sinks, stables, etc. In about three years these are washed, and each cubic foot of the mixture will furnish four or five ounces of saltpetre. It was manufactured in the Mammoth Cave, Kentucky, during the war of 1812. It dissolves in one-third of its weight of hot water. Properties and Uses. It is cooling and an antisep- tic : hence it is used for salting meat, to which it gives a reddish tint. It parts with its O readily and burns brilliantly. Every government keeps a large supply on hand for making gunpowder, in the event of war. Gunpowder is composed of three parts char- coal, and one each of saltpetre and sulphur. Its explosive force is due to the expansive power of the SODIUM. 107 gases formed. The combustion is started by the saltpetre giving up all its O to burn the S and C. The reaction that ensues may be very simply stated as follows : KO.NO S + S 4- 30 KB + N + 3CO 2 N and CO 2 are gases, and in that great heat of nearly 2,000, high enough to melt gold or copper, the KS becomes a vapor. With the sudden increase of temperature, they expand till they occupy 2,000 times the space of the powder. The bad odor of burnt pojvder is due to the slow formation of HS in the residuum. Fireworks are composed of gun- powder ground with additional C and S, and some coloring matter. Zinc filings produce green stars, steel filings variegated ones, A little chlorate of potassa tinges the flame with crimson. Salts of copper give a blue or a green light, and camphor a pure white one. SODIUM. Symbol, Ma---- Equivalent, 23 .... Specific Gravity, 0.972. This metal is found principally in common salt. It is very like K in its appearance, properties, and reaction. When thrown on HO it rolls over its sur- face like a beautiful little silver ball : if 'the HO be heated, it bursts into a yellowish blaze. The test of 108 ELEMENTARY CHEMISTRY. all the soda salts is the yellow tint which their solu- tion in alcohol gives to the flame. CHLORIDE OF SODIUM (NaCl), common salt, is the only mineral substance which is absolutely necessary to the life alike of all human beings and the higher order of animals. Among the many cruel punish- ments inflicted in China, deprivation of salt is said to be one, causing at first a most indescribable long- ing and anxiety, and finally a painful death. Dr. Draper tells us that the salt and the HO in the stomach undergo the following reaction : NaCl + HO IXF NaO+HCl Both these are essential in forming gastric juice and bile, and to make enough of them to keep up the proper digestion of our food, requires about one- third of an ounce of NaCl. As salt is so universally necessary, it is found everywhere. Our Father, in fitting up a home for us, did not forget to provide for all our wants. The quantity of salt in the ocean is said to be equal to five times the mass of the Alps. Salt lakes are scattered here and there ; saline springs abound ; and besides these, in the earth are stored great mines, probably produced by the evaporation of salt lakes in some ancient period of the earth's history. At Cracow, Poland, is a bed twelve hun- dred miles long, twenty miles wide, and a quarter SODIUM. 109 of a mile thick. In Spain, and lately in Idaho, it has been quarried out in perfect cubes, transparent as glass, so that a person can read through a large mass. On the sea-shore it is manufactured by the evaporation of sea-water, each gallon containing about four ounces. At Syracuse, New York, near by and underneath the Onondaga Lake, is appa- rently a great basin of salt-water, separated from the fresh-water above by an impervious bed of clay. Penetrating this to a depth of about seven hundred feet, the saline water is pumped up in immense quantities. The State sells this to salt manufactur- ers, on the payment of a cent per bushel on the salt made. The HO is evaporated by heating in large iron kettles or vats, or in the sun, whence the name "solar salt." If boiled down rapidly, fine table- salt is made ; if more slowly, coarse salt, as large crystals have time to form. Frequently they assume a "hopper shape" one cube appears, then others Hopper Form. 110 ELEMENTAEY CHEMISTEY. collect at its edges, and gradually settle, until a hol- low pyramid of salt-cubes, with its apex downward, is formed. About seven million barrels are made annually at this city. Salt dissolves equally well in hot or in cold water, and a saturated solution (one containing all it will dissolve) has 37 per cent, of salt. SULPHATE OF SODA (NaO.SO 3 ), Glauber's salts, named from the discoverer, is made from common gait. NaCl + HO.SOs NaO.SO 3 + HC1 Experiment : Make a saturated solution of sulphate of soda, and with it fill a bottle. Either put in the glass stopple or cover the top with a thin layer ot oil, and let the bottle stand. The salts will remain for weeks or even months without crystallizing ; but if they be taken up, and shaken ever so little, the whole mass will instantly form into crystals, so fill- ing the bottle that not a drop of water will escape, even if it be inverted. Should there be any hesita- tion in crystallizing at the moment, drop into the bottle a minute crystal of Glauber's Salts, and the effect will instantly be seen in the darting of new crystals in every direction. CABBONATE OF SODA (NaO.CO 2 ), sal-soda, is used in immense quantities in the manufacture of glass, SODIUM. Ill soap, etc. (See Appendix, Problem 40.) It is em- ployed, like borax, to soften hard water, by com- bining with the lime and magnesia, and making insoluble carbonates, which settle to the bottom. In washing, it unites with the grease in the clothes, and forms soap. BICARBONATE OF SODA (NaO . 2 CO 2 ) is the " soda' 1 of the cook-room, and is formed, like saleratus, from its carbonate. SILICATE OF SODA AND LIME (NaO.SiO 2 4- CaO. SiO 2 ) French plate and window glass. Glass was known to the ancients. Hieroglyphics, that are as old as the sojourn of the Israelites in Egypt, repre- sent glass-blowers at work, much after the fashion of the present. In the ruins of Nineveh, articles of glass, such as vases, lenses, etc., have been discovered. Mummies, three thousand years old, are adorned with glass beads. The inventor is not known. Pliny tells us that some merchants, once encamping on the sea-shore, found in the remains of their fire bits of glass, formed from the sand and ashes of the sea-weed by the heat ; but this is impossible, as an open fire could not be sufficient to melt these materials. In the fourth century, the glass-works at Alexandria produced most exquisite ornaments, with raised figures beau- tifully cut and gilded. As late, however, as the twelfth century, a house with glass windows was esteemed something magnificent ; and we read that in 1577, during Queen Elizabeth's reign, when the 112 ELEMENTARY CHEMISTRY. Duke of Northumberland came to town to pass the winter, the windows of his castle were taken out and packed away for safe-keeping until spring. Preparation. Glass is a double silicate, being composed of silica and any two of the alkaline bases, lime, soda, potash, or magnesia. Example : Fine white sand is mixed with sal-soda and lime, and then heated in earthen pots to the most intense degree for forty-eight hours. The materials fuse and form a double silicate of soda and lime. This is common window-glass. A variation in the ma- terials used produces different kinds of glass. The only essential ingredients are sand and soda or sand and potassa. Lime hardens and gives lustre, while soda imparts a green tint. Arsenic whitens it. Oxyd of lead is used in large quantities, as high as one-half the weight, to form a soft glass, which can be ground into imitation gems, table-ware, chande- lier pendants, prisms, etc. Oxyd of iron gives an opaque green, as in common junk or green glass bottles. Boracic acid increases the refractive power for lenses in microscopes and telescopes. Bohemian glass is a silicate of potash and lime, and thus does not show the green tint of soda. Pul- verized flint was formerly used for sand, and hence the term flint-glass. COLORED GLASS. A small quantity of some metallic Oxyd, melted with the glass, gives any tint desired : AuO gives a ruby red ; MnO, an amethyst ; CuO, an azure blue; As and Sb a soft white enamel, as in SODIUM. 113 lamp-shades; SnO 2 , a hard enamel, as in watch- faces. ANNEALING GLASS. If the glass utensils were im- mediately used, they would be found extremely brit- tle, and would drop in pieces in the most unaccount- able way. The heat of the hand or a draft of cool air would sometimes crack off the thick bottom of a tumbler. They are therefore cooled very gradually for days, which allows the particles to assume their natural place, and the chemical attractions to become equalized. This principle is beautifully illustrated by the chemical toy known as the " Prince Kupert Drop." ORNAMENTAL WABE. Venetian balls or paper weights are made by arranging bits of colored glass in the form of fruits, flowers, etc., and then, inserting this ball into a hollow globe of transparent glass, still hot, the workman draws in his breath, and the pressure of the air above collapses the globe upon the colored glass, and leaves a concave surface in the top of the weight. The lens form always magni- fies the size of the figures within. TUBES AND BEADS. In making glass tubing, the workman inserts his iron blowing-tul^e into a pot of melted glass, and gathers upon the end a suitable amount : drawing this out, he blows into the tube, swelling the glass into a globular form. Another dip into the pot and another blow increase its size, until at last a second workman attaches an iron rod to the other end. The two men then separate on a 114 ELEMENTARY CHEMISTRY. rapid trot. The soft glass globe diminishes in size as it lengthens, until at last it hangs between them a glass tube of one hundred feet in length, and per- haps only a quarter of an inch in diameter. In making beads, these glass tubes are cut in small bits, and then worked about in a mixture of wet ashes and sand, until they are filled. Next they are put with loose sand into a rapidly-revolving cylinder over a hot furnace. The heat softens the glass, but the mixture within presses out the sides, and the sand grinds the edges, until at last the beads be- come round and perfect, and are taken out ready for market. AMMONIUM. AMMONIUM (NH 4 ) has never been separated, but is thought to be the base of ammonia (NH 3 ). In com- bination NH 3 combines with an atom of HO, becom- ing NH 3 . HO = NH 4 . 0. This is considered as the oxyd of the compound radical ammonium. Ex- ample : NO 5 + HO + NH 3 uniting, form NH 3 .HO. CALCIUM. 115 METALS OF THE ALKALINE EARTHS. These are Ba, Ca, and Mg, but the last two only are of general interest. CALCIUM. Symbol, Ca - -Equivalent, 20- -Specific Gravity, 1.57. This metal exists abundantly in limestone, gyp- sum, and, combined with phosphoric acid, in the bones of the body. It is commonly known only as an oxyd-lime. CaO (CAUSTIC or QUICKLIME) is obtained by heating limestone (CaO.CO 2 ) in large kilns. The CO 2 is driven off by the heat, and leaves the lime as a white solid. Properties. It is a strong alkali, and corrodes the flesh. Its test is CO 2 , producing a milky precipitate of CaO.CO 2 . It has such a strong affinity for HO, that 28 Ibs. of lime will absorb 9 Ibs. of HO, forming CaO.HO, or " slacked lime," and swelling up to three times its original size, with the evolution of much heat. It absorbs HO from the air, and then CO 2 , thus gradually becoming a carbonate of lime " air- slacked lime." It is more soluble in cold than hot water. A thin film of carbonate of lime will soon gather over a solution of lime exposed to the air. Uses. It is used in tanning leather to remove the hair. Whitewash is a " milk of lime" i f e., a mixture of CaO and HO. In mortar, lime hardens rapidly, 116 ELEMENTARY CHEMISTRY. in part by uniting with the silica of the sand to form a silicate, and also by absorbing CO 2 from the air to form carbonate of lime. In this process, the HO which the lime absorbed in slacking is given off ; this causes the dampness always seen on newly-plastered walls when the room is first warmed. For drying plastering it would be much better if the CO 2 of the fire could be sent directly into the room, as it would hasten the chemical change. " If common mortar be protected from the air it will remain without harden- ing for many years. It is stated that lime still in the condition of a hydrate has been found in the pyra- mids of Egypt. When the ruins of the old castle of Landsberg were removed, a lime-pit, that must have been in existence 300 years, was found in one of the vaults. The surface was carbonated to the depth of a few inches, but the lime below this was fresh as if just slacked, and was used in laying the foundations of the new building." (Am. Cyc.) If the lime contains a little clay, it is called water- lime, and will harden under water. Lime is valuable as a fertilizer. It acts by rapidly decomposing all vegetable matter, and thus forming ammonia for the use of plants. It also sets free the alkalies that are combined with silica in the soil, and furnishes them to the plants. It does not itself feed the plants, as almost any soil contains enough lime for that purpose. If applied to a compost heap, it will set free am- monia, which can be recognized by the odor: this is its most valuable constituent. The NH 3 can be CALCIUM. 117 saved by sprinkling the heap with very dilute SO 3 , or plaster, or by mixing it with dry muck, which will absorb the gas. If there is any copperas (produced by the oxydation of iron pyrites) in the soil, the lime will decompose it, forming gypsum and iron-rust (CaO.SO 3 + Fe 2 O 3 ), thus changing a noxious ingre- dient into an element of fertility. CABBONATE OF LIME. This includes all varieties of common limestone, chalk, marble, marl, and forms the principal part of corals, shells, and bones. Water charged with CO 2 absorbs carbonate of lime freely, which, when the gas escapes on exposure to the air, is deposited. In this manner, in limestone regions, the water trickling down into caverns has A Cave. formed " stalactites," which depend from the ceiling, and " stalagmites," that rise from the floor. These frequently assume most curious and grotesque forms, as in the Mammoth Cave. Around many springs, the water, charged with lime in solution, flows over moss or some vegetable substance, upon which the 118 ELEMENTARY CHEMISTRY. lime is deposited. The spongy stone thus formed is calcareous tufa, or "petrified moss." Whiting is a carbonate of lime, made by grinding chalk. MairUe is crystallized limestone. C/ialk or marl is a porous kind of limestone, formed from beds of shells, but not compressed as in common limestone. These minute shells may be detected by a powerful microscope, even in glazing scraped from a common visiting card. SULPHATE OF LIME (CaO.SO 3 ) Gypsum, Plaster, etc. This occurs as beautiful fibrous crystals in satin spar, as transparent plates in selenite, and as a snowy-white solid in alabaster. It is soft, and can be cut into rings, vases, etc. When heated it loses its water of crystallization, and falls into powder, called " Plaster of Paris," from its abundance near that city. Made into a paste with HO, it first swells up, and then immediately hardens into a solid mass. This property fits it for use in copying medals and statues, forming moulds, fastening metal tops on glass lamps, etc. Plaster is also used as a fertilizer. Its action is probably somewhat like that of lime, and in addition it gathers up ammonia and holds it for the plant. It is said that Franklin brought it into use by sowing it over a field of grain on the hill- side, so as to form, in gigantic letters, the sentence, " Effects of gypsum." The rapid growth produced soon brought out the words in bold relief, and decided the destiny of gypsum among farmers. Sulphite of lime (CaO.SO 2 ) should be distinguished from the sul- phate (CaO.SO 3 ). This is used for preserving cider. MAGNESIUM. 119 PHOSPHATE OF LIME is contained, as Ave have al- ready seen, in bones. If now we add to them SO 3 , it will take up a part of the lime, making sulphate of lime (plaster), and the phosphoric acid thus driven off will take refuge with the rest of the acid and share its lime, forming a s?^er-phosphate of lime. This is used very extensively as a fertilizer, and is, as we have described, a mixture of gypsum or plas- ter, lime, and phosphoric acid. The last furnishes phosphorus to the growing plant to store in its seeds. Example : Corn, wheat. Phosphate of lime and ammonia are the valuable constituents of " guano." MAGNESIUM. Symbol, Mg . Equivalent, 12 Specific Gravity, 1.7. Source. Mg is ' found in many rocks as meer- schaum, soapstone, and magnesian limestone, and is abundant also in sea-water. It gives to a stone a soapy feel. When pure, it has a silvery appearance and lustre. It is very light and tenacious as steel, while it is flexible as twine. It burns in the open air with a brilliant white light, casting dense shadows through an ordinary flame. This light possesses the actinic or chemical principle so perfectly, that it is used for taking photographs at night, views of coal- mines, interiors of dark churches, etc. It has every ray of the spectrum, and so does not, as does gas- light, change some of the colors of an object upon 120 ELEMENTARY CHEMISTRY. which it falls. Lamps for burning it are veiy exten- sively made in Boston. By means of clockwork, the metal, in the form of a narrow ribbon, is fed in front Magnesium Lamp. of a concave mirror, at the focus of which it burns. The product of the combustion of Mg is MgO, the very substance from which the metal was obtained. ALUMINUM. 121 It is probable that the process of preparation will be cheapened, so that magnesium may be furnished at a rate which will bring it within the scope of the arts. It would be invaluable for lighting stores in which fancy goods are sold, or for illuminating large halls by means of a single lamp suspended in the dome. CARBONATE OF MAGNESIA (MgO.CO 2 ). This is the " magnesia alba," or simple magnesia of the druggists. By driving off the CO 2 , calcined Mg is formed. Sul- phate of Mg (Mg.SO 3 ) is known as Epsom salts, from a celebrated spring in England in which it abounds. METALS OF THE EARTHS. These are Al, Gl, Zr, Y, Th, Er, Tb, Ce, Ln, D, In, Tl, Kb, Cs. All are extremely rare except the first. ALUMINUM. Sym., AI .... Equiv., 13-7 ....Spec. Grav., 2.5 .... Fusing Pt, 2283. This is commonly called the "clay-metal." It is named from alum, in which it occurs. It is the metallic base of all clay, argillaceous, and granite rocks. It is a bright white metal, does not oxydize in the air, nor, like silver, tarnish by HS. It gives a clear musical ring ; is lighter than glass, being only two and a half times as heavy as HO ; is duc- tile, malleable, and more tenacious than Fe. It 6 122 ELEMENTARY CHEMISTRY. dissolves in HC1 or in common vinegar, but is proof against SO 3 or NO 3 . On account of its abundance (every clay-bank is a mine of it) and useful properties, it must ultimately come into common use in the arts and domestic life. ALUMINA (A1 2 O 3 ). Pure alumina, crystallized in nature, forms valuable Oriental gems. They are variously colored by the oxyds ; blue, in the sap- phire ; green, in the emerald ; yellow, in the topaz ; red, in the ruby. Massive impure crystals, when powdered, are called emery, and are used for pol- ishing. SILICATE OF ALUMINA (A1 2 O 3 . Si0 2 ) common day. When the granite rocks decay, by the resistless and constant action of the air, rain, and frost, they crumble into clay. This gives firmness to the soil, and retains moisture, but is cold and tardy in pro- ducing vegetable growth. When free from iron, it is used for making tobacco-pipes. When colored by yellow or red oxyd of iron, it is known as ochre, and is employed in painting. Common stone and red earthen-ware are made from impure varieties of clay; porcelain and china-ware require the finest known. Fire-bricks and crucibles are made from a clay which contains much silica. Fullers' earth is a very porous kind, and by capillary attraction ab- sorbs grease and oil from cloth. Glazing. When any article of earthenware has been moulded from clay, it is then baked. The ware is now porous, and would not even hold HO. ALUMINUM. 123 A mixture of the coarse materials from Avhich glass is made is then spread over the vessel, and heatec^ till it melts and forms a per- fect glazing upon the clay. NaCl and sand form the glaz- ing on stoneware, jugs, etc. PbO makes a yellowish glaze, which is very injurious, as it will dissolve even in vinegar, and form sugar of lead, a dead- ly poison. The color of pottery- ware and brick is due to the oxyd of iron present in the -, c* . . . , - Baking Porcelain. clay. Some varieties have no iron, and so form white ware and brick. SULPHATE OF ALUMINA AND POTASH (KO.SO 3 -f A1 2 O 3 .3SO 3 + 24HO). Alum is formed by soaking clay with SO 3 , in large casks for several months, until the sulphate of alumina is formed, when potassa is added, and the whole mass becomes filled with crystals of the new salt. Instead of KO, other bases are sometimes used, and an iron, soda, or chrome alum is formed. When heated, alum loses its water of crystallization, froths up, and becomes a porous mass, known as " burnt alum." Alum is soluble in 18 parts of cold water. It is much used in dyeing. It unites with the coloring matter, and binds it to the fibres of the cloth. It is therefore called a mordant (mordeo, to bite). ALUM CRYSTALS. Beautiful octohedron crystals 124 ELEMENTARY CHEMISTBY. of alum are obtained by suspending threads in a saturated solution of this salt. In this manner alum- baskets, bouquets, etc., are made of any desired color. SPECTRUM ANALYSIS. Many of the metals named as rare have been lately discovered by what is termed Spectrum Analysis. We have already noticed that various metals impart a peculiar color to flame ; thus the soda salts give a yellow tinge, copper a green, etc. If now we look at these colored flames through a prism, we shall find the " spectrum," or bands of rainbow-colors we are familiar with, strangely ornamented with bright- tinted lines. Thus the spectrum of sodium has one bright yellow line ; silver, two green lines ; caesium, a beautiful blue line. Each metal makes a distinc- tive spectrum, even when the flame is colored by several substances at once. This method of analysis is so delicate that Y,TTB^,^FO,FF^ ^ a gramme of so- dium, or the ^o,o"oV, TOT ^ a gramme of lithium, can be detected in the flame of an alcohol lamp. For the more perfect examination of the spectra, a " spectroscope" is used. This consists of a tube with a narrow slit at one end, which lets only a single ray of colored light fall upon the prism within, and at the other a small telescope, through which one can look in upon the prism and examine the spec- trum. IBON. 125 THE HEAVY METALS. IBON. Symbol, Fe Equivalent, 28- Specific Gravity, 7.8. Iron is the symbol of civilization. Its value in the arts can be measured only by the progress of the present age. In its adaptations and employ- ments it has kept pace with scientific discoveries and improvements, so that the uses of iron may readily indicate the advancement of a nation. It is worth more to the world than all other metals combined. We could dispense with gold or silver, they largely minister to luxury and refinement, while iron repre- sents only the honest industry of labor. Its use is universal, and it is fitted alike for massive iron cables, and for screws so tiny that they can be seen only by the microscope, appearing to the naked eye like grains of black sand. " Iron vessels cross the ocean, Iron engines give them motion, Iron needles northward veering, Iron tillers vessels steering, Iron pipes our gas delivers, Iron bridges span our rivers, Iron pens are used for writing, Iron ink our thoughts inditing, Iron stoves for cooking victuals, Iron ovens, pots, and kettles, Iron horses draw our loads, Iron rails compose our roads, Iron anchors hold hi sands, 126 ELEMENTARY CHEMISTRY. Iron bolts and rods and bands, Iron houses, iron walls, Iron cannon, iron balls, Iron axes, knives, and chains, Iron augers, saws, and planes, Iron globules hi our blood,* Iron particles in food, Iron lightning-rods on spires, Iron telegraphic wires, Iron hammers, nails, and screws, Iron everything we use." Its abundance everywhere indicates how indis- pensable the Creator deemed it to the education and development of man. There is no " California" of iron. Each nation has its own supply. No other material is so enhanced by labor. A bar of Fe, worth $5, becomes worth, when made into horse- shoes, $10 ; into needles, $55 ; penknives, $3,285 ; shirt -buttons, $29,480; and in watch - springs, $240,000, or more than its weight in gold. OXYDS OF IRON. The most usual are : (1) BLACK or MAGNETIC OXYD OF IRON (Fe 3 O 4 ), as found in the loadstone, Swedish iron ore, scales which fly off in forging iron, and in the iron mountains of Missouri. It is also seen in the thin pellicles overstanding HO, producing a beautiful iridescent appearance, the color changing with the thickness of the oxyd : (2) The RED OXYD OF IRON sesquioxyd (Fe 2 O 3 ), as seen in * There is not probably enough iron in the blood of a full- grown person to make a ten-penny nail, yet it gives energy and life to the system. Iron is given in the form of a fine powder, or a citrate of iron, as a tonic, and is a powerful remedy. IBON. 127 bog-iron ore, in the beautiful radiated and fibrous specimens of brown and red hematite, in bricks and pottery- ware, and in common iron-rust. The sesqui- oxyd, when combined with HO, forms (3) HYDKATED SESQUIOXYD OF IBON (Fe 2 O 3 .HO), and has a yellow color, which is changed to red by heat, when the HO is expelled, as in burning of brick, etc. These oxyds give the yellow and black colors seen in clayey soils and on the surface of weather-beaten stones. The black gradually oxydizes into the yellow, and so a black stone forms a yellow sand or soil. Smelting of Iron Ores. Iron is not found pure, but is locked up with in an apparently useless stone. C is the key that is ready made and left for our use by the Creator. It only remains for us to apply it and turn the wards. The process adopted at the mines is very simple. A tall blast-furnace is con- structed of stone and lined with fire-brick. At the top is the door and at the bot- tom pipes for forcing in hot air, sometimes twelve thou- sand cubic feet per minute, by huge blowing-cylinders driven by steam-power. The furnace is filled with lime, _ . . A Blast-Furnace. stone, coal, and iron ore, in alternate layers, and the fire ignited. The C unites with 128 ELEMENTAEY CHEMISTBY. the O of the ore, and goes off as CO 2 . The limestone forms, with the other impurities, silica, etc., a richly- colored glassy slag, which rises to the top. The melted iron runs to the bottom, and is drawn off into channels cut in the sand on the floor of ^ie furnace. The large main one is called the soiv, and the smaller lateral ones the pigs, and hence the term pig-iron. Pr ope i ties. Iron when pure is white. As com- monly seen it has a gray tint, and is susceptible of a high polish. It is malleable and ductile. It has been beaten into leaves so thin that it has been used for writing-paper six hundred leaves being only half an inch in thickness and has been drawn into wire as fine as a hair. By constant jarring it loses its perfect crystalline structure, becoming rot- ten and brittle, so that the axles of cars, cannon, etc., are condemned after a certain time, although no flaw may appear. It is an exception to the law that " cold contracts," since at the instant of solidi- fication it expands, so as to copy exactly every line of the mould in which it is cast. This fits it per- fectly for castings. Almost the entire value of iron in the arts depends upon this fact. Otherwise we could never hammer out enough tools and machinery to keep the world at work. Was it chance or design that contrived all this nice planning so long even before man was made ? Varieties of Fe. The usual forms of iron are cast, wrought, and steel. These depend upon the quantity of C they contain. A cwt. of cast-iron has about IRON. 129 A Reverberatory Furnace. 6 Ibs. of C, a cwt. of wrought about J lb., and steel is between them in varying quantities. CAST FE is the form in which it comes from the fur- nace. It is brittle, cannot be welded, and is neither malleable nor ductile, but is adapted for castings. WROUGHT or MALLEABLE FE is made by burning out the C from cast-iron, in a current of highly-heated air, in what is called a re- verberatory furnace. The Fe is stirred up constantly, and exposed to the hot air by means of " long pud- dling-sticks," as they are termed, and then taken out .and beaten under a trip- hammer to force out all the slag, and bring the par- ticles of Fe nearer each other. It now takes on a fibrous structure, and can be welded, is malleable and ductile. It is hardened by being cooled rapidly, and softened by cooling slowly. The blacksmith tempers his work by plunging the article in cold HO. STEEL contains less C than cast and more than wrought iron. It is therefore made from the formei by taking out a part of the C, or from the latter by heating it in boxes of charcoal, and so adding C.* The value of steel depends largely upon the temper- * By what is now known extensively as " Bessemer's process of making steel," it is formed from pig-iron without the use of fuel. A current of hot air is carried up through the liquid iron, which burns out the carbon, and in its combustion* produces heat 130 ELEMENTARY CHEMISTRY. ing quality it possesses. As the metal cools, the film of oxyd on the surface gradually thickens, and so deepens in color. By watching this the workmen know when the exact degree of hardness is reached. Knives require an orange, chisels a crimson, springs and swords a blue tint. Cheap knives made of cast- iron are often covered with a superficial coating of steel. They are simply heated with charcoal a little time, so that the outside only becomes steelified, as it were. When we use such knives, we soon wear through this crust, and find cast-iron beneath, which will take no edge. Galvanized Fe. This is formed by dipping sheets of iron in melted zinc, a thin layer of which adheres to the iron and prevents oxydation. BISULPHURET OF FE (Fe 82), iron pyrites fool' s gold ; so called, because it is often mistaken by ignorant people for gold. It occurs in cubical crystals and bright shiny scales. It can be easily tested by roast- ing it on a hot shovel, when we will catch the well- known odor of the S. SULPHATE OF FE (FeO.SO 3 + 7HO) green vitriol, copperas, made at Stafford, Connecticut, from FeS2, by exposure to air and moisture. It is formed in the enough to continue the operation. When the iron is entirely decarbonized, enough iron, rich in carbon, called " spiegeleisen," or " looking-glass iron," is added to transform it into steel. At the conclusion, in less than twenty minutes commonly, the entire mass of tons weight is run out and cast into bars of the veiy best steel. This method lias revolutionized the oM modes of manufacture. ZINC. 131 same manner in the decay of rocks, containing iron pyrites, and is found in the soil Used in dyeing, making ink, and in photography. ZINC. Symb. Zn-..-Equiv. 32.5-. .-Spec. Crav. 7- --Fusing Point, 470 F. Source. Zinc, or " spelter" as it is called in com- merce, is found in ZnO, or red oxyd, in New Jersey, and as ZnS, or zinc blende, at many places. Preparation, ZnO is purified on the same prin- ciple as iron ore, by heating the powdered ore with C. The re- action is as follows : ZnO 4- Zn + CO Both these products distil as a vapor, and the Zn is condensed while GO escapes. _ Roasting Zinc Ore. Properties. Ordinary Zn is brittle, but singularly enough, when heated to 200 or 300 F., it becomes malleable, and is rolled out into the sheet Zn in use so commonly. It burns in the air with a magnificent green light, forming great flakes of ZnO, sometimes called " Philosopher's Wool." Example : On a red- hot ladle sprinkle some powdered saltpetre and Zn filings. The KO.NO 5 will furnish O, and the metal will burn with great brilliancy. When exposed to 132 ELEMENTARY CHEMISTRY. the air, Zn soon oxydizes, and the thin film of white oxyd, formed over its surface, protects it from further change. Uses. It has many economic uses, known to all. The oxyd, ZnO, is sold as zinc-white, and is much valued as a paint, since it is not deleterious to the painters, and does not blacken by HS like white- lead. The sulphate, ZnO . SO 3 (white vitriol), is a powerful emetic. T IN. Symb.Sn....Equiv. 56. ...Spec. Crav. 7.2- ...Fusing Point, 420 F. Sn is found mainly in Cornwall, England, in Jackson, New Hampshire, in slight quantities, and in Missouri. It is not ductile, but is very malleable, so that tinfoil is not more than y^Vrr of an i ncn i Q thickness. When quickly bent, it utters a shrill sound, called the " tin cry," caused by the crystals moving upon each other. The tendency of Sn to crystallize is remarkable. Example: Heat a piece of Sn till the coating begins to melt; then cool quickly and clean it in aqua-regia. The surface will be found to be covered with beautiful crystals of the metal. Ordinary tin-ware is formed by dipping sheet-iron in melted Sn, which produces an artificial coating of the latter metal. If we leave HO in a tin dish long, the yellow spots betray the presence of Fe. Tin does not oxydizo at ordinary temperatures. Sn0 2 , sold as putty poicder, and used for white COPPER. 133 enamel and for polishing glass, is formed by the action of NO 5 on Sn. Example : Pour a little dilute NO 5 on scraps of tin, and watch the evolution of nitrous acid fumes, and the formation of SnO 2 . SnS 2 is the ordinary mosaic gold used in printing the bronze letters and figures on handbills and wall-paper. Pins are made of brass wire, and then boiled with tin and cream of tartar. This gives a bright white surface to the metal. The pins are stuck in papers, as we see them, by machinery which picks them up out of a miscellaneous pile, counts them, and inserts them in the paper, com- plete for the market. The first part of the process is performed by a sort of coarse comb, which is thrust into the heap, and gathers up a pin in each of the spaces between the teeth. COPPER. Symb. Cu-..-Equiv. 31.7-.. -Spec. Crav. 8.9-... Fusing Pt. 1996 F. Sources. Found native near Lake Superior, fre- quently in masses of great size. In these mines are discovered stone hammers, the tools of a people more ancient than the Indians, who probably occu- pied this continent, and worked the mines. In the Western mounds copper instruments are found. Malachite, CuO . CO 2 , is the best known ore of copper. It is found in Siberia, and is worked into beautiful ornaments, much prized by the Russian nobles. . Properties. It is ductile, malleable,' and a cpn- 134 ELEMENTARY CHEMISTRY. ductor of electricity. Its vapor gives a characteristic and beautiful green color to flame. It is hardened by hammering, and softened by heating and plung- ing into cold HO, just the reverse of iron, which fact spoils all our good theories as to the cause in either case. In a damp atmosphere, the CO 2 unites with it, forming CuO.CO 2 , familiarly but improperly called verdigris. The true verdigris is acetate of Cu 0, and is produced when we soak pickles in brass or cop- per kettles ; the green color which results is simply this salt a deadly poison. Preserved fruits, etc., should never stand in such vessels, as the vegetable acids dissolve Cu readily. The black coating which col- lects on copper or brass kettles is the black oxyd of copper, CuO, and very poisonous. It dissolves readily in fats and oils. Such utensils should therefore be used only when perfectly bright, and then never with any fruits, sweetmeats, jellies, pickles, etc. Its sol- vent is NO 5 . Its test is NH 3 , forming in a solu- tion a pale blue precipitate, which dissolves in an excess of the reagent. SULPHATE OF COPPER (CuO.SO 3 -f 5HO) Hue vitriol is much used in dyeing, calico printing, and galvanic batteries. LEAD. Sym,, Pb...-Equiv., I03.6...-Spec. Gr., 1 1,44-... Fusing Pt.,6l2F. Sources. It is found almost pure in cubical crys- tals, but its most common ore is galeaa, a sulphuret LEAD. 135 (PbS), which is reduced by roasting in a reverbera- tory furnace. The S burns and leaves the metal. Properties. It is malleable, but contracts as it solidifies, so it cannot be used for castings. It is poi- sonous, though not immediately, as bullets have been swallowed, and then thrown off without any harm except the fright. Its effects seem to accumulate in the system, and finally to manifest themselves in some disease. Persons who use lead, as painters and plumbers, after a time suffer with colics, paraly- sis, etc. It is much used for water-pipes, and is the most convenient of any metal for that purpose. Pure water passing through the pipe will not corrode the lead, but the O of the air it contains forms an oxyd of lead which dissolves in the HO. If there are any sulphates or carbonates in the HO, these will form a coating over the lead, and protect it from further corrosion ; and as carbonate of lime is com- mon in all hard water, that is safe. If, when we ex- amine a lead pipe that is in constant use, we find it covered with a white film, that is a good sign ; but if it is bright, there is cause for alarm. Still, how- ever much may be said upon the danger, people will use lead pipes, and the following precautions should be observed : Always let the water run long enough in the morning before using, to remove all which has re- mained in tJie water-pipes during tJie night, and after the HO has been drawn off for awhile, when it is let on again, leave the faucet open until the pipe is thor- oughly washed. 136 ELEMENTARY CHEMISTRY. OXYD OF LEAD (PbO) is the well-known litharge, and is used in glass-making, in paints, and in glaz- ing earthenware, as we have elsewhere described. MINIUM, or red-lead (Pb 3 O 4 ), is used for coloring sealing-wax red, and as a paint. CARBONATE OF LEAD (PbO.CO 2 ). White-Lead. This salt is made in large quantities in the following manner. Thousands of earthen pots fitted with covers are filled with weak vinegar (acetic acid) and a small roll of lead, arranged in immense piles, and then covered with tan- bark. The acetic acid combines with the lead, but the CO 2 formed by the decom- A An earthen t p L-Acoiionead posing tan-bark creeps in under the cover, olu of driving off the acetic acid, and forming carbonate of lead. The acetic acid, thus dispossessed, attacks another portion of the lead, but is robbed again ; and so the process goes on, until at last all the lead is exhausted. White-lead is largely adulterated with sulphate of baryta heavy spar. This can be easily detected by digesting (gently heating) a little in NO 5 , or even in strong vinegar, which will form a soluble nitrate or acetate of all the lead in the paint, while the baryta will settle to the bottom as a white precipitate. ACETATE OF LEAD (PbO.A) Sugar of Lead. This salt has a sweet, pleasant taste, and has been fre- quently taken by mistake, owing to its being in such common use. It is a virulent poison. The antidote is Epsom salts, which forms an insoluble sulphate ARSENIC. 137 of lead. Water dissolves it readily. Ex. : If a piece of zinc, cut in small strips, be suspended in a bottle filled with a solution of this salt, the lead will be deposited upon it by voltaic action in beautiful metallic spangles, forming the "lead-tree." TheLeau-treo. Test of Pb. This is HS, which forms with the metal the black sulphuret of lead (PbS). A very comical illustration is as follows : Thicken a solution of PbO.A with a little gum-arabic, so as not to flow too readily from the pen, and then make the funniest drawing of which you can conceive. This, when dry, will be invisible. When it is to be used dampen the paper slightly on the wrong side, and then direct against it a jet of HS, and the picture will blacken into beauty. ARSENIC. Symbol, As Equivalent, 75- Specific Gravity, 5.8. Volatilizes without fusion at 356 F. This is a brittle, steel-gray metal, commonly sold when impure as Cobalt. If heated in the open air it gives off the odor of garlic, which is a test of As. ARSENIOUS ACID (As0 3 ). This is the well-known " ratsbane," and is sometimes sold as simply " arsenic." Preparation. It is made in Silesia, by roasting arsenical iron ore at the bottom of a tower, above which is a series of rooms through which the vapors 138 ELEMENTARY CHEMISTRY. ascend, and pass out through a chimney at the top. The As bums, forming AsO 3 , which collects as a white powder on the walls and floors of the cham- bers above. Its removal is a work of great danger. The workmen are entirely enveloped in a leathern dress and mask with glass eyes ; they breathe through a moistened sponge, thus filtering the air of the fine particles of arsenic floating through it. Yet, in spite of all these precautions, the workmen rarely live beyond forty. Properties. Arsenious acid (arsenic) is soluble in hot HO, and has a slightly sweetish taste. It is a powerful poison, doses of two or three grains being fatal, although an over-dose acts as an emetic. It is an antiseptic, and so in cases of poisoning fre- quently attracts attention by the perfect preservation of the body, even twenty or thirty years after the murder has been committed. The antidote is milk, whites of eggs, or s as ds (t 1 e later being good in almost any case of poisoning), taken immediately. The exact chemical antidote is the hydrated sequioxyd of iron, prepared by adding an ; Ikali to a solution of copperas (FeO . SO 3 ). The bulky precipitate soon reddens by the absorption of O from the air, and becomes the sesquioxyd. It must be perfectly fresh and moist to be of any value. MARSH'S TEST. There is no other poison which is so easily detected. Prepare a flask for the evolution of H. Ignite the jet of gas, and hold in the flame a cold porcelain dish. If the materials contain no AllSENIC. 139 As, it will remain untarnished. Now pour in through the funnel-tube a few drops of a solution of As (made by dissolving a little AsO 3 in HC1), and the color of the flame will be seen to change almost in- stantly, and a copious "metallic mirror" of As will be deposited on the dish. The gas formed in this experiment arsenuretted hydrogen is very poison- ous indeed, and the utmost care should be used to prevent its inhalation. In a case of poisoning, of Marsh' 3 Tept. course, the contents of the stomach would be substi- tuted for the solution of As, and many other testa besides this would be employed. "We can imagine with what care a chemist would conduct this test, and with what intense anxiety he would watch the porcelain dish as the flame played upon it, hesitating, and dreading the issue, as he felt the life of a fellow- being trembling on the result of his experiment. Arsenic-eating. It is said that the peasants in 140 ELEMENTARY CHEMISTRY. portions of Hungary are accustomed to eat As, both fasting and as a seasoning to their food. A very minute portion will warm and stimulate and aid in climbing lofty mountains. The arsenic-eaters are described as plump and rosy, and it is said that the young people resort to it as a species of cosmetic to make them more attractive. They begin with small doses, which are gradually increased ; but if the person should cease the practice at any time, all the symptoms of arsenic poisoning immediately appear. Horse-jockeys are said to feed arsenic to their horses to improve their flesh and speed. CHROMIUM. Symbol, Cr. This element is commonly known as combined with O in chromic acid, CrO 3 . The ruby owes its beautiful red to this acid. Bichromate of potassa, KO . 2CrO 3 , is a red salt, much used in the laboratory, dyeing, etc. Example : If we mix a solution of this salt and one of sugar of lead, a yellow-colored pre- cipitate will be formed, known as chrome yellow (PbO . CrO 3 ), valued in painting and dyeing. Ex. : Moisten a piece of flannel in a solution of sugar of lead (PbO. A), then in one of Glauber's Salts (NaO. SO 3 ), to change the acetate of lead to a sulphate of lead, and lastly, in one of bichromate of potash, when the cloth will be found to be dyed a per- manent yellow. MERCURY. THE NOBLE METALS. These are : Mercury, Silver, Gold, Platinum, Palladium, Iridium, Osmium, Ruthenium, Rhodium. MERCURY. Symbol, Hg---- Equivalent, 100- -Specific Gravity, 13.5. Freezes at -39 F-... Boils at 662? F. Mercury is also called quicksilver, because it runs about as if it were alive, and was supposed by the alchemists to contain silver. It was known very anciently, and the mines of Spain were worked by the Romans. Source. Cinnabar, HgS, a brilliant red ore, called also "vermilion," is the principal source of this metal. It is found native in Mexico in very small quantities, where the mines are said to have been discovered by a slave, who, in climbing a mountain, came to a very steep ascent. To aid him in sur- mounting this, he tried to draw himself up by a bush which grew in a crevice above. The shrub, however, giving way, was torn up by the roots, and a tiny stream, of what to him seemed liquid silver, trickled down upon him. Properties. Mercury emits a vapor at all temper- atures above 40 F. Its solvent is NO 5 . It is the only element, except bromine, that is fluid at ordi- nary temperatures. It forms an amalgam a union 142 ELEMENTARY CHEMISTRY. of Hg and a metal viz., gold or silver. We should therefore never touch a gold ring, for instance, to Hg, as it will cover it immediately with a thin film of this amalgam. Uses. Hg is extensively employed in the manufac- ture of thermometers, barometers, for silvering mir- rors, and extracting the precious metals from their ores. The well-known Uue-pill is Hg incorporated with chalk and flavored with liquorice. Mercurial ointment, " anguintum," is Hg and lard well rubbed together. This is chiefly employed as an unguent for domestic use, and in very populous schools. Hg is extensively employed in medicine, as calomel, Hg 2 . Cl, a subchloride of mercury. This can be dis- tinguished from any other substance for which it is liable to be mistaken, especially corrosive sublimate, from the fact that it is insoluble in HO, and perfectly tasteless. The action of Hg on the human system is too well known to need description. " In its me- tallic state, Hg has been taken with impunity in quantities of a pound weight" (Am. Cyc.}, but when finely divided, as in vapor or "blue-pill," its effects are marked. It renders the patient extremely sus- ceptible to colds, acts directly upon the liver, in- creasing the secretion of bile, and in over-doses produces " salivation." BED OXYD OF Hg, "red precipitate," is interesting, as the substance from which Priestley discovered O gas. CHLORIDE OF Hg (Hg.Cl), " corrosive sublimate," is MERCURY. 143 well known to housekeepers. It is a heavy, white solid, soluble in HO, and with a burning metallic taste. It has powerful antiseptic properties, and is used to preserve specimens in natural history. It is a deadly poison, and its antidote is white of eggs, milk, etc. Mirrors were anciently made of steel or silver, highly polished. They were very liable to rust and tarnish, and so a piece of sponge, sprinkled with pum- ice-stone, was suspended from the handle for rubbing the mirror before use. Seneca, in lamenting over the extravagance of his day among the old Romans, says : " Every young woman now-a-days must have a silver mirror." The process of silvering ordinary mirrors is as follows. Tinfoil is first spread evenly over the glass, and then the Hg is carefully poured over it. The two metals combine, forming a bright amalgam, which clings to the glass. The superfluous Hg is cautiously wiped or pressed off. When we look into a mirror we rarely realize what it has cost others to thus minister to our comfort. The workmen are short-lived. A paralysis sometimes attacks them within a few weeks after they enter the manufactory, and it is thought remarkable if a man escapes for a year or two. Its effects are similar to those we have just spoken of when treating of calo- mel ; the patient dances instead of walks, he cannot direct the motion of his arms, nor in some cases even masticate his food. 144 ELEMENTAEY CHEMISTRY. IKIDIUM. Symbol, Ir-..- Equivalent, 99 Specific Gravity, 21.15. This metal is named from Iris, the rainbow, be- cause of the beautiful color of its salts in solution. It is the heaviest of the elements, being over 21 times as heavy as water. When combined with Osmium, it makes " irodosmine," well known as the points of gold pens. PLATINUM. Symbol, Ft-.-. Equivalent, 98-6-.. . Specific Gravity, 21.5 Fusing Point, 4591 F. Source. Platinum is chiefly found in the Ural Mountains, where it occurs in alluvial deposits, in small, flattened grains. Properties. It resembles Ag in its appearance. It is the most ductile metal known, wire having been made from it so fine as to be invisible to the naked eye.* It is soluble in aqua-regia, but not in the simple acids. It does not oxydize in the air, is the most infusible of substances, and can be melted only * Wollaston's Method, as it is called, consists in covering fine platinum wire with several times its weight of silver, and then drawing this through the plates used for drawing wire until the finest hole is reached, when the wire is placed hi NO 6 , which dis- solves the Ag and leaves the Pt intact. This, in the form of the finest wire known, may be found in the solution by means of a microscope. A single ounce of Pt, it is said, will make a wire that would reach from New York to New Orleans. GOLD. 145 by the heat of the compound blow-pipe or voltaic battery. In the arts it is fused in the former man- ner. These properties fit it for use as crucibles in the laboratory, and for this purpose it is invaluable to the chemist. GOLD. Symbol, Au . . . . Equivalent, 196.4 .... Specific Gravity, 19.34. Fusing Point, 2016 F. Sources. Gold is widely diffused. It occurs some- times in cubes, in masses called nuggets, and is always native. It is found generally in small grains, or scales, scattered through the rocks. As these disintegrate by the action of the elements, the gold is gradually washed into the valleys below, and thence into the streams and rivers, where, owing to its specific gravity, it settles and collects in the mud and gravel of their beds. In this way we trace the origin of the extensive gold-plains of California. Preparation. As the metal is thus found native, the process is purely mechanical, and consists simply in washing out the dirt and gravel in wash-pans, rockers, etc., at the bottom of which the metal ac- cumulates, the only requisites being these tools and an abundance of water. In the quartz-mills the rock is thrown into great troughs of water, in which, by heavy stamps, the ore is crushed to powder. As the thin liquid mud thus formed splashes up on either side, or is conducted from the stamping-mill, it runs 7 146 ELEMENTAKY CHEMISTRY. over broad metallic tables covered with mercury. This unites with the little particles of gold as they are washed along, and forms with them an amalgam (a compound of mercury and a metal). From this the gold is easily separated by distillation, and the mercury collected to be used again. QUARTATION. Gold is sometimes alloyed with sil- ver. In that case the silver is dissolved out by NO 5 . There must be three parts of silver to one of gold, else the gold will protect all the silver from the action of the acid. If there is not so much, some is added. Properties. Pure ore is nearly as soft as lead. It is extremely malleable and ductile. Its solvent is aqua-regia. It does not oxydize at any temperature. GOLD-LEAF. The process of making gold-leaf is very simple. The metal is first rolled into thin rib- bon, and then divided into pieces one inch square. These are placed, one by one, between leaves of gold-beaters' skin and hammered until they are beaten four inches square, when they are subdivided into four pieces, each one inch square. These are hammered as before, and the process repeated until the required thinness is obtained. Symb.,Ag....Equiv. f I08-. ..Spec. Or., 10.5... -Fusing Pt., 1873" F, Sources. Silver is found throughout tie great West in a distracting variety of forms most ccm- SILVER. 147 monly, however, combined with S, as black sulphur et, AgS ; with Cl, forming horn-silver, AgCl ; with As, making ruby-silver, AgAs, and also associated with lead in ordinary galena. Preparation. 1st. The sulphuret is refined as fol- lows. The ore is crushed into fine powder and then roasted with common salt. The Cl of the salt unites with the Ag, forming chloride of silver, AgCl. This is now put into a revolving cylinder with HO, Hg, and iron-scraps. The iron takes the Cl away from the silver, and the Hg catches it up, thus forming an amalgam of Hg and Ag. From this the silver is easily obtained, as in gold-washing. 2d. From horn-silver, AgCl, the process is like the latter part of that we have just described. 3d. From lead the silver can be profitably obtained even when there is not more than ten ounces in a ton. The aUoy of the two metals is melted and then slowly cooled. Lead solidifies much sooner than silver, and by skimming out the crystals of Pb as fast as formed, they may be almost entirely separated. Cupellation. A cupel is a shallow vessel, made of bone-ashes. In this the silver, debased with lead and other impurities, is placed and exposed to a red heat, so as to melt the metals, while a current of hot air plays upon the surface. The lead A c i )Cl - oxydizes, is changed to litharge, PbO, and is ab- sorbed by the porous cupel. The mass appears soiled and tarnished, but the refiner keeps his eye 148 ELEMENTARY CHEMISTRY. upon it as the process continues, watching eagerly, until at last there is a brilliant play of colors he catches his own image in the perfect metallic mirror, and the little " button" of pure silver lies gleaming at the bottom.* This must now be immediately re- moved, or it will oxydize and waste. Cupels in Furnace. Properties. Silver is the whitest of all the metals. It is malleable and ductile. It expands at the mo- ment it solidifies, and, therefore, can be cast. It has a powerful attraction for sulphur, forming the black sulphuret of silver. The perspiration from our bodies contains more or less S, and this, as it * Malachi, ill 3. SILVER. 149 passes through our pockets, fraternizes with any sil- ver we may chance to have there. Silver spoons and door-knobs are tarnished by the minute quan- tity of HS present in the air. Those who have visited any sulphur springs know the propriety of carefully protecting their gold or silver watches, and of never carrying them to the hot baths. AgS is very easily dissolved by a little dilute ammonia (1 part of NH 3 to 10 of HO), which is therefore used for cleaning silver door-knobs. The solvent of Ag is NO 5 . The test of silver in solution is HC1, which forms a cloudy precipitate of chloride of silver, AgCl. A solution of silver coin is blue, from the copper it contains. NITRATE OF SILVER (AgO.NO 5 ). It is sold in crys- tals, and also in sticks as lunar caustic. It js used as a cautery. It stains the skin and all organic mat- ter black, owing to its decomposition by the light and the formation of oxyd of silver, AgO. A very pretty experiment, illustrating this, is performed by dropping into a test-tube of HO a few drops of nitrate of silver in solution, and then adding KO : a copious precipitate of AgO will fill the tube. At last add a little NH 3 , and it will instantly dissolve the black oxyd, and leave the solution as clear and sparkling as spring-water. The stain from nitrate of silver may be removed by a solution of cyanide of potassium. Hair-dyes and indelible inks consist mainly of this salt of silver. 150 ELEMENTARY CHEMISTRY. THE ALLOYS. These are very numerous, and many of them possess properties so different from their elements that they almost seem like new metals. Their color and hardness are changed, and sometimes the melt- ing point is below that of any one of the con- stituents. Type Meted contains 3 parts lead to 1 of antimony. Britannia consists of 100 parts tin, 8 antimony, 2 bismuth, and 2 of copper. Brass is 4 parts of copper and 3 of zinc. German Silver contains copper, zinc, and nickel (brass whitened by nickel). Soft Solder, used by tinsmiths, is made by melting lead and tin together, the orthodox proportion half and half. Before putting on the solder, they moisten the surface of the metal with HC1, which dissolves the coating of the oxyd. Hard Solder is composed of copper and zinc. Fusible Metal melts at 203, and spoons made of it will fuse in hot tea. It can be melted in a paper crucible over a candle. It consists of bismuth, lead, and tin. Yet the first metal melts at 476, the second at 600, and the third at 442. Bronze is 90 parts copper and 10 of tin. Gold is soldered with an alloy of itself and silver ; Silver, with itself and copper ; Copper, with itself and zinc : the principle being that the metal of lower fusing point causes the other to melt more easily. THE ALLOYS. 151 COIN. The precious metals, when pure, are too soft for common use. They are therefore hardened by other metals. Gold coin consists of 9 parts gold and 1 of alloy. The alloy is composed of 9 parts of copper, whitened by one of silver, so as not to darken the gold coin. Silver coin is 9 parts silver and 1 of copper. The nickel cent is 88 parts copper and 12 of nickel. The object of the copper is to make the coin larger, as it is cheaper than nickel. The term carat, applied to the precious metals, means -J f part. Therefore, gold 18 carats fine, contains Jf of gold and 2 6 of alloy. SHOT is an alloy of about 1 part arsenic to 100 of lead. The manufacture is carried on in what are called " shot-towers," some of which are two hundred and fifty feet high. The alloy is melted at the top of the building, and poured through colanders. The metal, in falling so far, breaks up into drops, which take the " spheroidal form," harden, and are caught at the bottom in a well of water, which cools the shot and also prevents their being bruised in striking. The shot are dipped out, dried, and then assorted, by sifting in a revolving cylinder, which is set slightly inclined and is perforated with holes, in- creasing in size from the top to the bottom. The shot being poured in at the top, the small ones drop through first, next the larger, and so on, till the largest reach the very bottom. Each size is received in its own box. Shot are polished by being agi- tated for several hours with black-lead, in a rapidly 152 ELEMENTARY CHEMISTRY. revolving wheel. The shot are finally tested by rolling them all down a series of inclined planes placed at a little distance from each other. The spherical shot will jump from one plane to the next, while the imperfect ones will fall short, and drop below ; or sometimes, by rolling down a single in- clined plane, the spherical ones will go to the bot- tom, while the imperfect ones roll off at the sides. OREIDE a beautiful alloy, resembling gold is made at Waterbury, Connecticut. It is a French discovery. It consists of 100 parts copper, tin 17 parts, magnesia 6 parts, sal-ammoniac 3.6 parts, lime 1.8 parts, cream of tartar 9 parts. It can be beaten into leaves, cast, chased, rolled, and stamped like gold, while none but the most experienced judges can detect the difference. ALUMINUM alloys with copper are becoming valu- able, as Al is itself better known. They are elastic, malleable, and very light. ORGANIC CHEMISTRY. INTRODUCTION. WE have thus far spoken of the various elements of matter. We have found " dead, mineral matter," as we commonly call it, all alive with desire and power. Each tiny atom has revealed to us a force that repelled it here, attracted it there, and held it to its place as with bands of iron. We have traced, through all the varied changes of matter, the workings of one law and one system, and have every- where discovered our comfort and happiness to be the final end of creation. We have found the nicest cutting and planning, whereby each element appears fitted to its place in nature, as a skilful mechanic adapts one cog to another through a great series of machinery. No particle of matter seems left to itself, but, watched by the Eternal Eye and guided by the Eternal Hand, obeys immutable law. When Christ declared the very hairs of our head to be numbered, he intimated a chemical truth, which we can now know in full to be, that the very atoms of 154 ELEMENTARY CHEMISTRY. which each hair is composed are all numbered by that same watchful Providence. We have found the elements of the growth of our bodies, but still we cannot live upon them. We need phosphorus, but we cannot eat it ; it would burn us to a coal. We need iron, but it would make a most unsavory diet. We need lime, but it would corrode our flesh. We need H, but it must be com- bined with O as HO to be of any value to us. If we were shut up in a room with all the elements of nature, we not only could not combine them so as to produce any of those organic substances necessary to our life and comfort, but we would actually die of starvation. We thus see that the mineral matter must be assimilated in some manner before we can use it to advantage. Here appears the object of the vegetable world. It turns inorganic matter into organic. The plant taking those elements which we need for our growth and for use in the arts and sciences, combines them into plant products, such as wood, starch, sugar, coal, etc. : we using these, live, grow, and develop into civilized man, fitted for all the grand achievements of life. How strange it is that we are thus dependent upon plants! We know they decompose the poisonous CO 2 , and give us our supply of the inspiring O, but that is only a part of our demands ; they furnish us with all the grand staples of commerce, of luxury- all we eat, or drink, or wear. Each tiny leaf we see, each spire of grass is thus incessantly working INTRODUCTION. 155 throughout the livelong day to meet our constant wants. The object of ORGANIC CHEMISTRY is to treat of these plant-products and the various substances de- rived from them. Organic bodies differ from inor- ganic in several points. 1st. While inorganic bodies deal with 65 elements, organic are composed principally of only four, C, H, O, N which are therefore called " ORGANOGENS" and a very little mineral matter constituting the ash. 2d. While inorganic bodies consist of only a few atoms, and are therefore very simple in their con- struction (Ex. : HO, CO 2 , KO), organic contain a large number, and are extremely complex. Ex. : Sugar =C 12 H 12 O 12 ; Oil of cedar = C^H^Oz'y Fibrine = 3d. While inorganic bodies are formed and remain fixed in one state under the influence of chemical affinity, organic grow rapidly, change constantly, and when life ceases, as rapidly decay, and are trans- formed into inorganic substances. 4th. Owing to their complex structure, and the presence in very many of the negative N, they form most unstable compounds. In this we see the reason of their rapid decay. The vital principle alone holds them together, frequently in opposition to the laws of chemical affinity ; and the instant that is removed, the tendency is to seek new affinities and form new compounds. 7* f 156 ELEMENTARY CHEMISTEY. NUMBER OF ORGANIC BODIES. This is almost end- less, and yet is constantly increasing. The labor of modern chemists is largely devoted to this subject, and the field opens and broadens with every dis- covery. The methods of classification are unsettled, and new and conflicting theories yet contend on this border-ground of chemical knowledge. Various or- ganic bodies are now formed artificially by the skill of the chemist, and many others are broken up into simpler forms. Ex. : Alcohol = water and carburet- ted hydrogen. ISOMERISM. Isomeric compounds are those that consist of the same elements in the same proportion. Ex. : Heavy carburetted hydrogen, petroleum, oil of roses, and caoutchouc, consist alike of C 4 H 4 . So that the fragrant odor of a rose, and that which comes from a petroleum lamp, contain precisely the same elements. Isomerism is supposed to be caused by a different grouping of the atoms about each other, as the same pieces upon a checker-board may be differently arranged. ALLOTROPISM. Not only may the same elements be thus differently grouped, and produce different com- pounds, as p-l-e-a may spell also 1-e-a-p, or p-e-a-1, or p-a-l-e, but also the individual elements are sus- ceptible of allotropic states ; as, for instance, the C in a compound may be in any one of its three allo- tropic forms. These two principles of isomerism and allotropism run through organic chemistry, and STARCH. 157 readily account for the inexhaustible variety of its compounds.* STARCH (C 12 H 10 Oi ). Source. Plants accumulate it in their roots Ex., Carrot, turnip : in subterranean stems Ex., Pota- toes, of which it forms 20 per cent. : in the base of leaves Ex., Onion: in the seed Ex., Corn, of which it forms 80 per cent: in the embryo Ex., Bean, pea. In all these it is stored up for the future growth of the plant or the seed. It is kept in its starch form (lest it dissolve in the first rain), and then turned to sugar only when and as the plant needs it in growing. The ac- companying figures show the form of the i ra'n of starch in a potato, as seen under the microscope, each veg tab'o having its peculiar shape, so that in this way any adulteration is easily detected. Preparation. It is .made from wheat, corn, pota- toes. The process is essentially the same in all. The potato, for example, is ground to a pulp, and Starch Grain. * See ORGANIC CHEMISTRY, in Appendix. 158 ELEMENTARY CHEMISTRY. then washed with cold water. The starch settles from this milky mass as a fine white precipitate. Properties. It is insoluble in cold water. If heated it absorbs water, swells, and the starch granules burst, forming a jelly-like liquid, used for what is known as starching. The swelling of rice, beans, etc., when cooked, is owing to this property. By heat, starch undergoes a peculiar change into a substance known as dextrine, or British gum, used for making envelopes, wall-paper, "fig-paste," and for stiffening chintzes. The test of starch is iodine, which forms in solution a beautiful blue iodide of starch. Sago is the starch from the pith of the palm-tree ; tapioca and arrow-root are made from the roots of South American marshy plants. Very many of the farinaceous preparations sold for the sick and invalid, under high-sounding names, are simply wheat or corn starch, put up in fancy papers and gilt lettering. GUM (C 12 H 10 O 10 ). This includes a variety of sub- stances which exude from the bark of trees. Ex. : Cherry, plum. Gum-arabic is derived from an Aca- cia tree. . STARCH. 159 PECTIC ACID, OR PECTINE. This is a variety of gum existing in certain fruits, as the currant, apple, etc., which forms the vegetable jelly so much used as a sweetmeat. In the fully ripened fruit, this turns to sugar, and hence, as every housewife knows, a jelly cannot be made from the fruit except at a cer- tain stage in the ripening process. CELLULOSE, LIGNINE, ETC. (Ci 2 H 10 O 10 ). Woody fibre is found in various modifications in the heart of a tree, in shells of nuts, and stones of fruits. Its cells, filled with lignin, are hard and compact ; in the sap- wood, its cells, open and full only of sap, are soft and porous; in elder-pith and cork, they are light; in flax and cotton, pliable ; in the bran of wheat and corn, very digestible. It composes the cells of ah 1 plants, giving them strength and firmness, and is found even in delicate fruits, holding their luscious juices. Secretion. All vegetation consists of these simple cells. They seem alike to the eye, yet they have a won- derful power of secretion. The cell of the sugar- maple converts the sap into sugar the milk-weed, into a milky juice the caoutchouc, into rubber ; the pie-plant manufactures oxalic acid, and the rose-petal the most delicate of perfumes. Then again they are true to themselves. There seems to be a law of God stamped on each cell, so that when we cut a tiny bud from a tree and graft it into another, it remains con- sistent with itself. It develops into a limb, and years pass by the few single cells become a myriad, yet 160 ELEMENTARY CHEMISTRY. they have changed not. The sap flows upward in the tree ; but at a certain point a hidden threshold which no human eye can discern it comes under a new and strange influence. It is here transformed, and produces fruit and flowers, in accordance with this new law. Somehow quince-juice is made into pears, locust-juice blooms out into fragrant acacias, while sweet apples and sour apples hang "cheek- by-jowl" on the same limb. Uses. These are wonderfully various. Woody fibre is woven into cloth, built into houses, -twisted into rope, twine, and thread, cut into fuel, carved into furniture. We eat it, wear it, walk on it, write on it, sit on it, print on it, pack our clothes in it, sleep in it, ride in it, and burn it. Curious Discovery. It has lately been found that, by feeding the roots of a tree with some coloring matter, the wood of the trunk may be stained to imitate any color desired. In this way, common pine or maple takes the appearance of the rarest wood mahogany, rosewood, etc. PAPER is made from rags of all kinds, straw, or indeed almost any substance containing cellular tissue. The finest writing-paper is manufactured from the best of linen rags, brought from Italy. The rags are first shredded upon scythe blades i. e., the seams are ripped open, buttons cut off, and the dust shaken out. 2d. They are steamed in a solu- tion of chloride of lime for ten or twelve hours until they are ikorougldy bleached. 3d. They are received STARCH. 161 by a machine that alternately lacerates them by a cylinder set with razor-like blades, and washes them with pure cold water for six hours, or until they are reduced to a mass resembling rice and milk. 4th. This mass receives a delicate blue tint from smalt powdered glass colored with oxyd of cobalt. 5th. It is diluted with HO to the consistency of city milk, and sifted, to strain out the waxed ends and knots of thread that cause the provoking little lumps that catch our pen when we write rapidly on poor paper. 6th. It flows over an endless or circular belt of wire- gauze, about 30 feet long, beneath which is a steam air-pump that greedily sucks down the water from the pulp, as it slowly passes along, gaining consist- ency and firmness until it comes to a part of the belt called the " dandy-roll," consisting of a cylinder, on the surface of which are wires arranged in parallel rows, or fancy letters, which print upon the moist paper any design constituting what are termed "laid," "wire-wove," or "water-marks." 7th. The paper, very soft and moist as yet, but still quite paperish in its appearance, passes between rollers that squeeze out the water; then between others which are hot and dry it, which bring it, 8th, to a vat of sizing, composed of the same material as the gelatin of calves-foot jelly, into which it plunges, and at the opposite side emerges only to come be- tween other rollers that squeeze and dry it at the end of which it passes under a cylinder, set with knives, that clip the roll into sheets of any desired size. 162 ELEMENTARY CHEMISTRY. PARCHMENT is prepared by plunging unsized paper for a few seconds in SO 3 and HO, then washing off the acid. This strengthens it in some unknown way, and entirely changes its appearance and character, so that a narrow strip will support a hundred pound weight, though before a small fraction of that would have torn it instantly. LINEN. This is made from the inner bark of flax. The plant is first pulled from the ground to preserve the entire length of the stalk ; next " rotted" by ex- posure to air and moisture, when the decayed outer bark is removed by "breaking;" then, by "hatchel- ing," the long fine fibres are divided into shreds, and laid parallel, while the tangled ones are separated as " tow." It is then bleached on the grass, which renders the gray coloring-matter soluble by boiling in lye. The whitened flax is lastly woven into cloth. COTTON consists of the beautiful hollow white hairs arranged around the seed of the cotton-plant. As it is always pure and white except Nankin cotton, which is yellow it would require no bleaching did it not become soiled in the process of spinning, etc. GUN-COTTON is prepared by dipping cellular tissue cotton, sawdust, printing-paper, etc. in strong NO 5 . It is then carefully washed and dried. It is not materially changed in appearance, although it has less strength. It sometimes takes fire at the boiling-point of HO. It explodes with much greater violence and suddenness than gunpowder, and for that reason is more liable to burst the gun. STARCH. 1(33 COLLODION is a solution of gun-cotton in sulphuric ether and alcohol. It forms a syrupy liquid, which is an excellent substitute for courtplaster. EREMACAUSIS. When wood decays slowly in the open air, the H passes off first, the proportion of C increases, the color darkens, and a black carbona- ceous mass like muck remains, called humus. This is of great value to the soil, as its pores absorb NH 3 , and by its decay furnishes that and C0 2 to the grow- ing plant. When the supply of humus is exhausted from the soil, we restore it by adding straw, etc., and by ploughing under green crops. DESTRUCTIVE DISTILLATION OF WOOD. When wood is heated to a high temperature, with no O present, or an imperfect supply, as in our stoves, it is decom- posed, the charcoal remains, while the volatile con- stituents pass over in the form of illuminating gas, HO, pyroligneous acid, and wood-tar. This latter is a thick liquid used for calking and tarring ships : on distillation it yields benzole, creosote, and paraffins. PYROLIGNEOUS ACID (wood-vinegar) is obtained by the distillation of beech-wood. It contains much creosote and acetic acid. On account of the former property it is used for curing hams in commerce, and on account of the latter, for making salts called acetates. CREOSOTE (flesh preserver) is a colorless liquid with a flavor of burnt wood. It is poisonous when taken in any quantity. It is a powerful antiseptic, and a mixture of 1 part creosote in 100 parts HO will, in a 164 ELEMENTARY -CHEMISTRY. few hours, give a ham a delicate smoky flavor and render it incapable of putrefaction. Creosote im- parts to smoke its characteristic odor, and renders it so irritating to the eyes, and also gives to it the power of curing hams, dried beef, etc. TAR is made, like charcoal, by burning heaps of wood under a covering of earth which excludes the air: an imperfect combustion ensues, the resinous matter exudes, and, trickling down to the hollow bottom, collects and runs into a reservoir. On the extensive pine-barrens of North Carolina the tar of commerce is principally produced. TURPENTINE. When tar is distilled it separates into pitch, which remains, and oil of turpentine, which passes off. The latter, redistilled, forms the rectified " spirits of turpentine." The residuum of the distil- lation is called "rosin." COAL-TAR is formed, as we have seen, in the process of making illuminating gas. This was formerly thought valueless, but is now used for a variety of purposes. As a cement for roofs, walks, and pave- ments, for oiling machinery, and preserving wood from decay, it is invaluable. On distillation it yields the following, among other products: 1st, lenzole (benzine), used as a solvent for gutta-percha, caoutchouc, wax, and for removing grease-spots. This, by distilling with NO 5 , gives nitro-benzole, which so nearly resembles the oil of bitter almonds that it is used for it in perfumery, confectionery, etc. By heating it with acetic acid and iron-lings STARCH. 165 anaUne is commonly prepared. 2d, Par&ffine, a hard, white, tasteless solid, like spermaceti. It forms beautiful candles, which look and burn like the finest of wax. 3d, Analine, from which some of the most exquisite colors of every shade are produced. Example : Mauve, magenta. When first prepared, analine was worth more than gold, and is even now expensive ; but its dyeing properties are very intense. (Who but a chemist would have searched for such brilliant colors in coal-tar !) 4th, Carbolic add, which, by heating with NO 5 , dyes a rich yellow ; it is also used as- a disinfectant. The production of dye-stuffs from coal-tar formed an era in organic chemistry, and revolutionized the whole art of dyeing and calico-printing. PETROLEUM is doubtless the product of the distil- lation of organic matter beneath the surface of the earth. It is not always connected with coal, as it is often found outside the coal-measures, as in North- western Pennsylvania and New York. The distilla- tion must have taken place at a much greater depth than that at which the oil is now found, as it would naturally rise through the fissures of the rock and gather in the cavities above. Sometimes the oil has collected on the surface of subterranean pools of salt-water, so that after a time the oil is exhausted, and salt-water only is pumped up ; or if the well strikes the lower part of the cavity, the water will first be pumped and afterward the oil. The crude oil from the well is purified by distillation. That 166 ELEMENTARY CHEMISTRY. which passes over at the lowest temperature is called naphtha : as the heat is increased, there passes over next the kerosene oil for illumination, and lastly the lubricating oil. The kerosene is deodorized and decolorized by the use of sugar of lead, SO 3 , KO, and other chemicals, which are stirred in the oil, after which it is redistilled. Bitumen or Asphaltum. Petroleum (petra, a rock, and oleum, oil) and naphtha, flowing from the ground, have formed beds of bitumen in various parts of the world. This change is caused by a gradual oxydation and hardening, as turpentine changes to rosin. On the island of Trinidad is a lake called Tar Lake. It is nearly three miles in circumference. Below it is a bed of coal, from which the oil is doubtless distilled. The bitumen from the lake is used for the same purposes as pitch, which it closely resembles. Near the shore it is hard and compact, except in hot weather, when it becomes sticky. At the centre it is soft, and fresh bitumen boils up to the surface. Asphaltum is found in im- mense quantities in California and in Canada. It is a natural cement for laying stone or brick. It was used in building the walls of Babylon, for which purpose it was gathered from the fountain of Is on the banks of the Euphrates. It was a prominent ingredient in the " Greek Fire," so much used by the nations of Eastern Europe in their naval wars, even as late as the fourteenth century. This con- sisted of bitumen, sulphur, and pitch, which was STARCH. 167 thrown through long copper tubes, from hideous figures erected on the prow of the vessel. It was said to be inextinguishable except by wine or vine- gar. Bitumen is used in making the famous prome- nades of the Boulevards in Paris. CANE-SUGAR (C 12 HnOu)* is obtained from the sap of the sugar-maple, sugar-cane, sorghum, and the juice of the beet. In making it from the sugar-cane, the canes are crushed between iron cylinders, thus expressing the juice. As it sours very soon, from the heat of the climate in which it grows, a little lime is added to neutralize the acid, and it is then evaporated to a thick jelly, and set aside to cool. The sugar crystallizes readily, forming brown sugar, which is put in perforated casks to drain. The drainings constitute molasses. Refining of Sugar. Brown sugar is refined by dis- solving it in HO, then adding albumen (whites of eggs, blood, etc.), which, on heating, coagulates and settles to the bottom with the coarser impurities. The solution is then filtered through animal charcoal, * Ex. : A very brilliant illustration of the presence of C in C, a H I1 O Il is obtained by putting on a clean white plate a mixture of finely pulverized white sugar and KO.C1O 6 . Upon adding a few drops of SO 3 , a vivid combustion will ensue. By mixing also a few iron and steel filings, and performing the experiment in a dark room, or out of doors at night, fiery rosettes will flash through a rose-colored flame, and produce a fine effect. The contrast between the white plate and mixture and the dense black carbonaceous compound covering the adjacent floor, is very strik- ing to the eye. 168 ELEMENTARY CHEMISTRY. and finally evaporated in vacuum-pans, from which the air is exhausted, so that the sugar boils at 140F., and all danger of burning is avoided. From this the sugar crystallizes, and the white sugar is set aside to drain. The drainings constitute " syrup," " sugar- house molasses," etc. BOCK CANDY is formed by suspending threads in a strong solution of sugar. It crystallizes upon the rough surface in large six-sided prisms. CONFECTIONERY is commonly supposed to be made from sugar. Alba terra (white earth) is now largely imported from Ireland for use in lozenges, candy drops, etc., enough sugar only to flavor being added. We can and should test all the candy we purchase by putting a small piece in a glass of water. What- ever settles to the bottom cannot be sugar, but is a vile adulteration. Candies also are often colored by the direst poisons, so that prudence would forbid the use of any colored candy whatsoever. The grocer or dealer is as liable to be mistaken or igno- rant in regard to the purity of his candies as we ourselves. Licorice drops are frequently only the poorest brown sugar, terra alba, and a flavoring of licorice to make the unwholesome mixture palatable. Gum-drops are generally made, not from gum-arabic, but the best kinds are composed of a species of glue manufactured out of hoofs, parings of hides, offal, etc., from the slaughter-houses. And yet, however repugnant it may appear, this glue is perfectly clean and wholesomj. Many kinds of gum-drops and STARCH. 169 lozenges are made from dextrine, terra alba, plaster of Paris, a little sugar, and some flavoring extract. CAROMEL, familiarly called burnt sugar, is formed whenever sugar is heated above 400 F., when it parts with four equivalents of water, leaving the C in excess, as when sweetmeats boil over on the stove. It is used extensively in coloring liquors. GRAPE-SUGAR (C 12 H. U O U ). This variety of sugar includes the sugar of grapes, figs, all common fruits, honey, etc., in which forms we are familiar with it. It has much less sweetness than cane-sugar. SUGAR FROM STARCH OR WOOD. Starch and woody fibre differ only from grape-sugar by four atoms of HO. By slowly heating with SO 3 , diluted largely with HO, common sawdust, paper, and old rags even, can be converted into sugar. Indeed, Profes- sor Pepper speaks of eating a fine quality of grape- sugar made out of an old flannel shirt he had out- grown. The weight of sugar exceeds that of the woody fibre used by the additional four elements of HO. This change takes place in the plant. The green fruit contains starch, which, as the fruit ripens, is turned into grape-sugar. If it over-ripens, the sweetness is lost, as the sugar is reabsorbed by the plant and converted into woody fibre again. In the sap of the sugar-maple tree there is much grape- sugar, but as the leaves start they hasten to stop this pilfering of their sweet juices by turning it into cellular tissue into the wood of the tree. The farmer knows that if he does not cut his grass at the 8 170 ELEMENTARY CHEMISTRY. proper time it will undergo this change, and become tough and tasteless and of little value to him. The starch in potatoes is turned to sugar by freezing, and so frozen potatoes taste sweet. FEKMENTATION. If a solution of starch or sugar be exposed to the air it will undergo no change, but if there be added a little ferment or yeast, flour-paste, or any albu- minous substance (i. e., one containing N), in a de- composing state, it will immediately commence breaking up into new compounds. There are two stages in this chemical change. 1st. ALCOHOLIC FERMENTATION. In this, the sugar is resolved into alcohol, water, and carbonic acid. The two former remain in the liquid, while the latter escapes in little bubbles of gas. The reaction is as follows : H u 2d. ACETOUS FERMENTATION. The second stage succeeds the first immediately, if not checked, and by absorbing oxygen from the air, the alcohol is broken up into acetic add and water. FERMENTATION. 171 C 4 H 6 O 2 4- 4 (from tlie air) C 4 H 4 O 4 + 2HO YEAST is composed of microscopic plants formed during the process of fermentation. So minute are they, that it is said a cubic inch contains 1,200,000,000 of them. In the malting of barley they spring up in great abundance, making common brewer's yeast. The yeast-cakes of the kitchen are formed by expos- ing moistened Indian meal, containing a ferment, to a moderate temperature until the gluten or albu- minous matter of the cake has undergone this alco- holic fermentation. It is then, laid aside for use. A heat of 212, or a cold of 10, will kill the yeast plant and destroy its efficiency as a ferment. MALT. In making malt, the barley is thoroughly moistened, and then spread on the floor of a dark room (malting-room), to heat and sprout. Here a curious change ensues, identical with that which takes place in every planted seed. Each one con- tains starch and a nitrogenous substance called glu- ten. The tiny plant not being able to support itself in the beginning, has here a little patrimony to start with in life, but, as the starch is insoluble in its sap, it must first be changed to sugar. We see, there- fore, the need of a ferment ; but it would not answer to store up in the seed an active ferment, as that might cause a change befcre the plant was ready to 172 ELEMENTARY CHEMISTRY. grow, and thus the plant's capital be wasted. The gluten is therefore a latent ferment, as it were. As soon as the seed is planted it absorbs moisture from the ground, is turned into diastase an active fer- ment the starch is converted into sugar, dissolved, and immediately applied to the uses of the growing plant. This change takes place in the malting-room. The barley sprouts, and a part of its starch is turned to sugar, so that it tastes quite sweet. If this germination were allowed to proceed, the little barley sprout would turn this sugar into woody fibre. To prevent this the grain is heated in a kiln until the germ is destroyed. Barley in this condition is called malt, and is then transported to the breweries. BREWING BEER. The malt is crushed and digested in water, to convert all the remaining starch into sugar. Having been boiled, to clarify it, hops and yeast are added, and fermentation immediately com- mences. Bubbles of gas rise to the top with a low hissing sound, yeast gathers into a foamy cream that comes to the surface of the tub, and the alcohol gradually accumulates in the liquid. It is now drawn off into tight casks, where it undergoes a sec- ond fermentation ; the flavor of the beer ripens, and the CO 2 collecting, gives to the liquor, when drawn, its sparkling, foamy appearance. LAGER BEER (Lagen, to lie) is so called because it is allowed to lie for months in a cool cellar, where it ripens very gradually. It is also fermented much more dowly and perfectly than ale or porter. FERMENTATION. 173 WINES are commonly made from the juice of the grape. The juice, or must, as it is called, is placed in vats in the cellar, where the low temperature pro- duces a very slow fermentation. Before the sugar is all converted into CO 2 and alcohol, the wine is bottled. The undecomposed sugar gives the flavor to sweet wines, while the CO 2 , formed afterward and dissolved in the liquid, produces the effervescence of sparkling wines. The sugar keeps the wine and rather improves its body for even a couple of centu- ries. The bouquet, or flavor of wines, is given by a very volatile liquid called cenanthic ether. It is de- veloped in its perfection by age alone, and gives the value to old wines. The acidity of wine is due to a small quantity of tartaric acid combined with KO, forming the bitartrate of potash (cream of tartar), which gradually separates and collects upon the sides and bottoms of the casks and bottles in a white incrustation. ALCOHOL IN BEER AND WINE. Alcohol is the in- toxicating principle alike of all varieties of liquors, ale, beer, wine, cider, and the domestic wines. Ale contains from five to ten per cent, of alcohol ; wine varies from five per cent, in the light Champagne to twenty-five per cent, in the strong Port, Madeira, or Sherry. ARDENT SPIRITS. When any fermented liquor is distilled, the alcohol passes over at a temperature of 173, together with some water and fragrant substances which are condensed. In this way 174 ELEMENTARY CHEMISTRY. brandy is made from wine ; rum from fermented molasses ; whiskey from fermented corn, rye, or po- tatoes ; gin from fermented barley and rye, after- ward redistilled with juniper-berries ; alcohol alone from whiskey. The percentage of alcohol in these spirituous liquors varies from fifty to seventy per cent. The accompanying cut represents an appara- tus used for this distillation. A is the boiler, B the A Still. dome, C a tube passing into S, the condenser, where it is twisted into a spiral form called the worm, in which the vapor from the boiler is condensed, and drops out at D. ALCOHOL (C 4 H 6 O 2 ) is prepared by distilling whiskey, FERMENTATION. 175 and is sometimes called spirits of wine. It boils at 173, and has never been frozen even at 166 F. It contains, when purest, ten per cent, of HO, which can be separated by adding some substance like CaCl, which has a strong affinity for HO. It is then called anhydrous or absolute alcohol. When C 4 H 6 O 2 is exposed to the air the spirit evaporates, while it also attracts moisture from the atmosphere. The chemist discovers this when he neglects to put the extinguisher on his alcohol-lamp and finds that he cannot relight it without moistening the wick with fresh alcohol. It burns without smoke and with intense heat, owing to the abundance of H and deficiency of C, and is therefore of great value in the arts. It is also of incalculable importance as a solvent in forming tinctures of many substances roots, resins, fragrant oils, etc. Effects of Alcohol. When pure it is a deadly poison. When diluted, as in the ordinary liquors, it is stimu- lative and intoxicating. Its influence is on the brain and nervous system ; deadening the natural affections, dulling the intellectual operations and moral instincts ; seeming to pervert and destroy all that is pure and holy in man, while it robs him of his highest attribute reason. It is a blight upon a family, a curse to society, and the bane of our civili- zation. In a word, alcohol makes drunkards, and a drunkard is the saddest, most shocking sight this world affords. ETHEK (CJI 5 O). Sulphuric ether is formed by the 176 ELEMENTARY CHEMISTRY. distillation of C 4 H G O 2 with SO 3 . The SO 3 simply takes an atom of HO out of the alcohol. It has a fragrant odor, boils at 96, and burns with more light and smoke but less heat than alcohol. By the action of the other acids on CiUjC^ varieties of ether are produced viz., nitric ether, carbonic ether, etc. AMYLIC ALCOHOL (fusel ail) is one of a large class of substances similar to alcohol, and thus called " the alcohols." It is formed in distilling whiskey from potatoes. It is present in common C 4 H 6 O 2 , giving that slightly unpleasant odor when it evaporates from the hand. It is extremely poisonous, and though contained in liquors in very small quantities, is said to greatly increase their destructive and in- toxicating properties. It is of interest, mainly be- cause by distilling it with different acids, various products are obtained, having the most delicate flavor and odor. Pear, apple, orange, and many other " flavoring essences" are thus prepared. Though made from the poisonous fusel oil, they are perfectly innocuous. CHLOROFORM (C 2 HC1) is made by distilling C 4 H 6 O 2 with chloride of lime. It is colorless, volatile, of a sweet taste, and should be free from any unpleas- ant odor when evaporated on the hand. It is mainly used as an anaesthetic. The value of ether and chloroform in alleviating pain, is beyond estimate. On the battle-field, in hospitals, everywhere, our soldiers have sunk into pleasant slumber, while the FERMENTATION. 177 most painful surgical operations have been per- formed. ACETIC ACID (C 4 H 4 O 4 , A). When any fermenting substance has reached the first stage the alcoholic fermentation if the process be not stopped, it passes on to the second the acetous fermentation, forming acetic acid and water. This acid is well known as common vinegar, of which it forms about five per cent. The acid of commerce is prepared by the action of SO 3 on acetate of lead (sugar of lead) PbO . A. The reaction is PbO.l + SO 3 PbO.SO 3 + A. CIDEK YINEGAE. Cider contains some nitrogenous matter, which acts as a ferment, and the vinegar of the apple is broken up into alcohol and carbonic acid. This makes what is called " old cider." By ex- posure to the air and heat, which always hastens chemical change, the alcohol passes on to the second stage, and the acetic acid formed produces the sour taste of the vinegar. " Mother" in vinegar, is a plant produced by the decomposition of the nitrogenous matter. It acts as a ferment, and frequently generates a nation of infusoria vinegar eels. Acetic acid is a solvent of albumen, gelatin, fibrin, etc. Hence it takes from meat, eggs, oysters, etc., pickled in it, their most strengthening constituents. For the 178 ELEMENTABY CHEMISTEY. same reason, vinegar is a valuable assistant in digest- ing such food. It allays thirst, and was anciently carried by the Boman soldiers in a little flask for that purpose. In the case of young ladies who use it (as well as slate-pencils), to relieve corpulency, it produces delicacy and finally consumption. Any sugar added to vinegar quickly passes to the second stage of fermentation, and increases its strength. Indeed, vinegar is sometimes made entirely from tea-leaves, which act as the ferment, and sweetened water. Vinegars of commerce are frequently sharp- ened by the addition of SO 3 and pungent spices. We can easily detect these by evaporating a half- gill in a saucer, placed over boiling water. As it boils down, add a little honey. If the grape-sugar it contains turns black, it is proof of the presence of SO 3 . As the last of the liquid evaporates, the odor of cayenne pepper, etc. (if there be any), can be readily distinguished. A new Method. The following method has lately been adopted in England. A thin liquid made from malt and HO is allowed to pass into the first stage of fermentation. A large vat is filled with short pieces of wicker-work, which are kept wet with an old vinegar wash until the surface of the wicker-work is covered with young vinegar-plants; these grow until they fill all the empty space. The weak alco- holic liquid is now permitted to trickle down through this vat full of mother, while at the same time the heat of the chemical change causes an upward cur- FERMENTATION. 179 rent of air through holes at the bottom of the vat. Before the liquid reaches the faucet below, it presses into the second stage of fermentation. QUICK VINEGAR PROCESS. Vinegar is now made on a large scale by filtering a mix- ture of alcohol and yeast through a cask filled with beech shavings soaked in vinegar. As the ferment- ing alcohol slowly trickles down, it comes in close contact with the air, absorbing O so rapidly that some- times before it reaches the bottom it becomes entirely converted into vinegar. PRESERVES frequently work, as it is called, and then sour. The bubbles of gas which rise to the surface indicate the first or alcoholic stage of fer- mentation. If neglected, this soon passes to the second. It may be checked by scalding, which de- stroys the ferment. VEGETABLE ACIDS. There are many of these found native in plants most generally, however, combined with some base. OXALIC ACID (C 4 H 6 ; O) is familiar in the sour taste of pie-plant, sorrel, etc., in which it is combined with KO, which largely neutralizes its acid properties. It is prepared by the action of NO 5 on sugar.* O * Oxalic acid is also made on a large scale from sawdust, soda, and potash. The woody fibre is resolved into oxalic acid, 180 ELEMENTARY CHEMISTRY. is a potent poison. Its antidote is a drink of pow- dered magnesia, or chalk, stirred in HO. It is a test of lime, forming a delicate white precipitate of oxalate of lime. Its solution is much used to re- move ink stains, and it is sold for this purpose under the deceptive and dangerous name of " salts of lemon." The acid unites with the iron of the ink, and the oxalate of iron thus made is easily dis- solved in HO. It should be thus washed out im- mediately, as it will corrode the cloth. The crystals of O, it should be noticed, very much resemble those of Epsom salts, and many serious mistakes have oc- curred in consequence. TARTARIC ACID (C 8 H 4 O 10 , T) exists in many fruits, principally in the grape, combined with KO as KO.2T, the bitartrate of potassa. This settles during the making of wine, as we have seen, and when puri- fied is called cream of tartar. From this T is made. It forms large, colorless crystals, of a pleasant acid taste, which are permanent in the air. Its solution gradually becomes mouldy and turns into A. Eo- clielle salt is a double tartrate of potassa and soda ; it is a purgative, and is much used in Kochelle, or S&idlitz, powders. These are combined in a blue and a white paper. The former holds 120 grains of Rochelle salt, and 40 grains of bicarbonate of soda ; which combines with the bases, forming oxalates of soda and potash. From these the acid is readily obtained. Sawdust will yield more than half its weight of crystals of this salt VEGETABLE ACIDS. 181 the latter 35 grains of tartaric acid. These are dis- solved in separate goblets. The one containing the acid is emptied into the other, when the CO 2 is set free, producing a violent effervescence and disguis- ing the taste of the medicine. Tartar emetic is a double tartrate of potassa and antimony. CITEIC ACID (citrus, lemon) is the sour principle of the citron, orange, lemon, cranberry, etc. It is com- bined with lime in the onion. MALIC ACID (medics, an apple) is found in the apple, peach, pear, plum, cherry, etc. TANNIC ACID (tannin) is found in the leaves and bark of many trees. Example : Oak, hemlock, su- mach. Nutgalls is an excrescence which forms on oak-trees \dien punctured by insects for the purpose of laying their eggs. Tea and coffee contain from 8 to 10 per cent, of tannin. It has a bitter, astrin- gent, puckering taste, is soluble in water, and har- dens all albuminous substances, such as gelatine, etc. TANNING. After the hair has been removed from the skins by milk o lime, they are soaked for days, the best kinds for months, in vats full of water and ground oak or hemlock bark (tan-bark). The tannic acid of the bark is dissolved, and entering the pores of the skin, unites with the gelatin, forming a hard insoluble compound which is the basis of leather. Leather is blackened by washing the hide on on 3 side with a solution of copperas (FeO.SO 3 ). Ths tannic acid unite . v>.th the iron, forming a tannuta 182 ELEMENTARY CHEMISTEY. of iron a real ink. In the same way drops of tea on a knife-blade stain it black. INK is made by adding a solution of nutgalls to one of copperas. The tannate of iron thus formed has a pale blue-black color, as in the best writing- inks. By exposure to the air the iron absorbs more O, and becomes changed from the protoxide to the sesquioxide, thus darkening in color until it is a deep black. Gum-arabic is added to the ink to thicken it and regulate its flow from the pen. Cloves or corrosive sublimate are used to prevent mouldi- ness. Steel pens are corroded by the free SO 3 con- tained in the ink, but gold pens are not affected by it. Experiment. The following is an instructive ex- periment, illustrating the manner of making ink, of removing stains with oxalic acid, and also the relative strength of the acids and alkalies. Take a large test-tube, and add the following reagents in solution cautiously, drop by drop, watching the re- sult and explaining the reactions : Sulphate of iron (copperas) FeO . SO 3 Tannic acid (tannin) Cs4 Has Oa4 Oxalic acid C 4 H, Carbonate of soda (sal-soda) NaO . CO a Hydrochloric acid (muriatic) HC1 Ammonia (hartsliorn) NH 3 Nitric acid (aquafortis) NO 6 Potassa (potash) KO Sulphuric acid (oil of vitriol) SO S GALLIC ACID is always a companion of tannin in OILS AND FATS. 183 the substances we have named, and is formed from it by exposure to the air. In some hair-dyes the hair is first wet with gallic acid, and then with a solution of nitrate of silver. The acid decomposes the salt, and the liberated oxyd of silver colors the hair. OILS AND FATS. The difference between oils and fats is only that of temperature; the former remain liquid at ordi- nary degrees of heat, while the latter is a solid. " A fat may be called a solid oil, and an oil a liquid fat," with equal propriety. The peculiar odor of each is due to some volatile acid. They are divided into two classes fixed oils and volatile oils. The former produce a permanent stain on paper, the latter do not. " A cork twisted into the neck of a bottle con- taining a fixed oil makes no noise ; in a volatile oil it squeaks.' THE FIXED OILS. Constitution. All fatty bodies are salts, being composed of stearin, margarin, and olein. These consist of three acids stearic, margaric, and oleic, combined with a common base, glycerin ; thus : Stearic acid, ) ( Stearin. Margaric acid, > with Glycerin (as a base), form -< Margarin. Oleic acid, ) ( Olein. 184 ELEMENTARY CHEMISTRY. The first two of these salts are solids at common temperatures, and form fats ; the latter is a liquid, and forms oils. The relative proportion of olein contained in any fatty substance determines its flu- idity. Ex. : Stearin is abundant in tallow, and mar- garin in butter, hence their comparative consistency. Lard, on the other hand, contains so much olein that it is expressed in large quantities as " lard-oil." Olive- oil contains much olein and margarin; the former remains fluid at ordinary temperatures, but the latter, in cold weather, hardens into a thick deposit, and renders the oil extremely viscid. GLYCERIN is named from its sweet taste. It is made from tallow, and is an odorless transparent syrup. It is soluble in HO and alcohol. Its healing properties are remarkable, and its use is common in dressing sores, insect bites, chapped hands, etc. When highly heated it is decomposed, and produces an acrid substance (acroleine) with which we are familiar in the disagreeable smell of a smouldering candle-wick and burning fat. By the action of NO 5 and SO 3 glycerin is con- verted into nitro-glycerin, an oil that explodes with most fearful violence by the slightest concussion, or even from unexplainable causes. It is used in blasting. LYE is a strong solution of KO, and is obtained, as we have seen, by leaching ashes. The alkali is contained in the ashes in the form of KO.CO 2 . At the bottom of the leach-tub a little lime is commonly THE FIXED OILS. 185 placed to absorb the C0 2 and leave the KO unneutral- ized by the acid, and therefore stronger. HOME-MADE SOAPS are formed by heating " lye" and " soap-grease." In this process the potassa of the lye drives off the glycerin of the grease and makes new salts which contain KO, instead of gly- cerin, as the base ; thus : Stearic acid, ) x ( Stearate of potassa. T. , / with Potassa (as a base), \ ,. Marganc " V " { Margarate of " Oleic j cbangeto (oieateof " These three salts constitute soap. The expelled gly- cerin remains floating around alone through the mass. This soap is soft because of the attraction of KO for HO. The boiling merely hastens the chemical change. It takes place more slowly in the making of " cold soap." HARD SOAP contains soda instead of KO as a base. This is not deliquescent,* and so the soap retains its solid form. Soda soap can be formed from potassa soap by the addition of common salt (NaCl). Reaction. The O of the potassa (KO) unites with the sodium (Na) of the salt (NaCl), forming soda (NaO). The chlorine (Cl) of the salt (NaCl) unites with the potassium (K) of the potassa (KO), forming chloride of potassium (KC1). The soda thus formed displaces the potassa, and makes a hard or soda * A deliquescent body is one that dissolves in HO, which it absorbs from the air. 186 ELEMENTARY CHEMISTRY. soap, while the KC1 remains dissolved in the water ; thus : Stearate of \ KO NaCl ( Stearate of soda. Margarate of v = < Margarate of soc Oleate of J NaCl . NaO ( Oleate of soda. The kind of fat used, by the amount of olein it con- tains, also determines the softness of the soap. Ex. : Tallow makes a harder soap than lard, since it has less olein. Soap has a powerful affinity for HO, and will readily absorb 50 per cent, of its weight. It is therefore noticeable that dealers commonly keep their soaps in cellars or damp places. The best old soap contains at least 20 per cent. FANCY SOAPS. Castile soap is composed of olive- oil and soda. Its mottled appearance is caused by oxyd of iron, which is stirred through it in fanciful designs while it is yet soft. Yellow soaps contain rosin in part, instead of fat, forming a rosin soap. Cocoanut-oil makes a soap which will dissolve in salt water, and is therefore used at sea. It also forms a strong lather, and is sold as " shaving-soap." Wash- ing fluids contain an unusual amount of alkali, and are therefore apt to be injurious to the cloth. Soap- balls are made by dissolving soap in a very little water, and then working it with starch to a proper consistency to be shaped into balls. White toilet- soaps are made from lard and soda. SOAP IN HARD WATER. Water containing any min- eral matter will not dissolve soap, since the lime, THE FIXED OILS. 187 magnesia, etc., displace the alkali in the soap, and form a new soap which is not soluble, but floats on top as a greasy scum. Example : A potassa soap in lime-water changes to a lime soap. Thus Stearate of ^ / Stearate of \ Mar^arate of > KO, changes to < Margarate of j- CaO. Oleate of ' ' Oleate of ) THE CLEANSING QUALITIES OF SOAP. There exudes constantly from the pores of our skin an oily per- spiration, and this, catching the floating dust, dries into a film of greasy dirt which will not dissolve in water. The alkali of soap combines with this oily substance and makes a soap of it, which is soluble. In addition to this the alkali also dis- solves thi3 cuticle of our skin, and thus produces the " soapj r feeling," as we term it, when we handle soap. SOAPSUDS consists of a thin film of soap filled with bubbles of air. It is an excellent remedy in almost all cases of poisoning, and where the exact antidote is not at hand should be taken immediately. Soap- bubbles are said to be only two-millionths of an inch in thickness. (Newton.) They are thinnest at the top, as the water runs down the sides toward the bottom constantly. These falling films of water cause the refraction of light, and a beautiful play of colors. ADULTERATION. Soap is frequently contaminated 188 ELEMENTABY CHEMISTBY. with gypsum, lime, pipe-clay, etc. These may be detected by dissolving a small piece in alcohol and noticing if there be any precipitate. CANDLES are made from tallow, stearin, paraffine, wax, spermaceti, etc. Tallow candles and their manufacture are too well known to need description. Stearin or adamantine candles are moulded like or- dinary candles. They are prepared from tallow or lard, which is first boiled with lime and so made into a soap. This soap is decomposed by sulphuric acid, which takes away the lime, forming sulphate of lime, which, being insoluble, sinks to the bottom, leaving the three acids of the fat floating upon the surface. The glycerin is also left by itself in the liquid, from whence it is removed and prepared for the market. The acids, when cool, are subjected to great pressure ; the olein flows out, leaving the stearic and margaric acids as a milk-white, odorless, tasteless solid, which is commonly called stearin, since that acid is the principal constituent. Paraf- fine candles are made from coal-oil, as we have al- ready described. Wax candles are manufactured by the following process. A large number of cotton wicks are hung upon a revolving frame with project- ing arms. The wicks are fitted at the end with metal tags to keep the wax from covering that part. As the machine slowly turns, a man, standing ready with a vessel of melted wax, carefully pours a little down each wick in succession. This process con- tinues until the candles are fed to the desired size. THE FIXED OILS. 189 They are then well rolled on a smooth stone slab, the tops cut by conical tubes, the bottoms trimmed, and they are ready for use. The large tapers burned in Catholic cathedrals are made by placing the wick on a sheet of wax, rolling it up till the right thick- ness is reached, when the candle is trimmed and polished as before. Spermaceti candles are run from the white crystal- line solid fat which is found with sperm oil in the head of the sperm whale. WAX is found in nearly all plants. It forms the shiny coating of the leaves and fruit. Example : Lemon leaf, apple. Certain plants in Japan contain so much wax that it is separated by boiling and used for making candles. Bees gather the wax for the construction of their comb partly from flowers, and a part they manufacture from the sweet juices sipped from the flowers. Yellow beeswax is bleached by exposure in thin ribbons to the air. LINSEED OIL is a drying oil, as it is termed i. e., it absorbs O from the air, and hardens by exposure. It is expressed from flaxseed, which furnishes about one-fifth of its own weight of oil. Soiled oil is made by boiling the crude oil with litharge (PbO) for several hours. The oxyd of lead combines with the gummy mucilage of the oil, which collects as a slimy sediment. Linseed oil is used in mixing paints and varnishes. Putty consists of linseed oil and chalk ( Whiting) well mixed. Printers' ink is made by burn- ing linseed oil until it becomes thick and viscid, 190 ELEMENTARY CHEMISTRY. when lampblack is stirred in, to make it of the proper consistency. COD LITER OIL is extracted from the liver of the codfish. It contains I, Br, and P, and is much used as a remedy in Consumption. CROTON OIL is made from the seeds of an Indian plant ; and is used as a powerful purgative and for causing eruptions on the skin. CASTOR OIL is extracted from the castor-oil bean. It is used as a purgative, and also in perfumery and hair-oils. SWEET-OIL, OR OLIVE-OIL, is an unctuous oil, L e., it absorbs O on exposure to the air not hardening like the drying oils, but remaining sticky, and after a time becoming rancid from the formation of dis- agreeable volatile acids. Sweet-oil is expressed from the olive fruit. In Europe it is extensive- ly used instead of^butter. It is employed as a machine-oil, although the coal-oils are now much preferred. VOLATILE OILS. The Volatile oils, unlike the Fixed, make no soaps, and dissolve readily in alcohol or ether. Their so- lution in alcohol forms an essence, hence the term " essential," by which they are frequently called. Source. They are principally of vegetable origin. They are found in the petals of a flower, as the violet ; in the seed, as caraway ; in the leaves, as mint ; in the root, as sassafras ; and sometimes VOLATILE OILS. 191 several kinds of oil are obtained from different parts of the same plant. Example : The flower, leaves, and rind of the orange-tree furnish each its own variety. The perfume of flowers is produced by these volatile oils ; but how slight a quantity is present may be inferred from the fact tha/t one hundred pounds of fresh roses will give scarcely a quarter of an ounce of Attar of Roses. Preparation. In the peppermint, the wintergreen, and many others the plant is distilled with water. The oils pass over with the steam, and are con- densed in a refrigerator connected with the " Mint Still." The oil floats on the surface of the con- densed water, and may be removed. A small por- tion, however, remains mingled with the latter, which thus acquires its pecuUar taste and odor, constituting what are termed "perfumed waters." Example : Rose-water, peppermint-water. In some flowers, as the violet, jasmin, etc., the perfume is too delicate to be collected in this manner. They are therefore laid between woollen cloths saturated with some fixed oil. This absorbs the essential oil, which is then dissolved by alcohol. Oil of lemon is ob- tained from the rind of the fruit by expression or by digesting in alcohol. Example : A good essence is made by putting bits of lemon-peel in a bottle of alcohol. COMPOSITION. CJi^ is the common symbol of a large number of these oils. Thus the oils of lemon, jumper, citron, black pepper, copaiba, bergamot, 192 ELEMENTARY CHEMISTRY. turpentine, cubebs, and oranges, are isomeric. A second class contains, besides C and H, a little O ; a third, in addition, has S. FIRST CLASS OF VOLATILE OILS. Turpentine is a type of this division. It is made by distilling pitch with HO. It is generally called spirits of turpen- tine. It is highly inflammable, and, owing to the ex- cess of C, burns with a great smoke. By the union of an atom of its H with an atom of the O of the air to form HO, it is converted into rosin. In this way, when exposed in bottles half full, the turpen- tine around the nozzle becomes first sticky and then resinous. Old oil should not be taken to remove grease spots, as, while it will remove one, it will leave another of its own. Camphene is turpentine purified by repeated distillation. Burning-fluid is a mixture of camphene and alcohol. In the heat of the burning H of the latter, the C of the former is consumed, and this produces a bright light. The tendency of camphene to smoke is thus diminished, and the illuminating power increased. By the ac- tion of HC1 on turpentine or oil of lemons an arti- ficial camphor is produced very nearly resembling our common camphor. THE SECOND CLASS includes the oils of bitter al- monds, cinnamon, peppermint, roses, lavender, etc. They are sometimes called " The Camphors," because of their general resemblance to the crystalline essence known by that name. Camphor (C 6 H 4 O 2 ) is obtained by distilling the roots and loaves of the camphor- BESINS AND BALSAMS. 193 tree of Japan in water, and condensing the vapors in rice-straw. It is purified by sublimation. When kept in a bottle, it vaporizes, and its delicate crystals collect on the side toward the light. Taken internal- ly, except in small doses, it is a virulent poison. Its solution in alcohol is called spirits of camphor. If HO be added to this, the camphor will be precipita- ted as a flour-like powder. THE THIRD CLASS contains S, and sometimes N. It includes garlic, assafcetida, hops, onions, mustard, horseradish, etc. They are known for their pun- gent taste and the disagreeable odor they often im- part to the breath. The oil of mustard is not con- tained in the seed, but is formed in it by the action of water and a latent ferment. This is the reason why mustard, when first prepared for the table, is bitter, but becomes pungent after a little time. BESINS AND BALSAMS. Kesins are formed from the essential oils by oxy- dation. Example : Turpentine^ as we have just seen, is changed to rosin, a resinous substance. If the resin is dissolved in some essential oil it is called a balsam. Example : Pitch is a true balsam, since by distillation it is separated into rosin and turpentine. 9 194 ELEMENTARY CHEMISTRY. Source. They mostly exude from incisions in trees and shrubs, in the form of a balsam, which oxydizes on exposure to the air, and becomes a resin. Example : Common plum-tree, pine-tree. Properties of Resins.-^-Thvy are translucent, brittle, insoluble in HO, but soluble in ether, alcohol, or any volatile oil, are non-conductors of electricity, and burn with much smoke. They do not decay, and, indeed, have the power of preserving other sub- stances. For this reason they were used in em- balming the bodies of the ancient Egyptians, which, after the lapse of two thousand years, are yet found dried into mummies in their mammoth tombs the Pyramids. ROSIN constitutes about 75 per cent of pitch. It is used in making soaps, to increase friction in violin bows and the cords of clock-weights, in soldering, and as a source of illuminating gas. Shoemakers' wax is made by burning rosin until partly charred. LAC exudes from the ficus-tree of the East Indies. An insect punctures the bark, and the juice flows out over the insect, which works it into cells in which to deposit its eggs. The twigs incrusted with the dried gum is called stick-lac, when removed from the wood it is seed-lac, when melted and strained, shellac. The liquefied resin is dropped upon large leaves, and so cools in broad thin pieces, as we buy it. Sealing-wax is made of shellac and turpentine ; vermilion is added to give the red color. Shellac is much used in making varnishes. * RESINS AND BALSAMS. 195 GUM BENZOIN also exudes from a tree in the East Indies. It contains benzoic acid. It is used in fumigation, in cosmetics, and on account of its fra- grant odor is burnt as incense. Ex. : Place some green sprigs under a glass receiver, and at the bot- tom a hot ^iron, on which sprinkle a little benzoic acid. It will sublime and collect in beautifully deli- cate crystals on the green leaves above, making a perfect illustration of winter frost-work. AMBER is a fossil resin which has exuded in some past age of the world's history from trees now ex- tinct. It is sometimes found containing various in- sects perfectly preserved, which were without doubt entangled in the mass while it was yet soft. These are so beautifully embalmed in this transparent glass that they give us a good idea of the insect life of that age. It is cast up by the sea, in pieces of a few ounces each, on the shores of the Baltic and off the coast of New Jersey. It is commonly translucent, and susceptible of a high polish. It is used for or- naments, mouth-pieces, necklaces, buttons, etc. It is a prominent ingredient in carriage varnish. CAOUTCHOUC or INDIA-RUBBER is a pure hydro- carbon, and may be considered as hardened illumi- nating gas. It exudes from certain trees in South America as a milky juice. The globules of rubber are suspended in it as butter is in milk. By adding ammonia the sap may be kept unchanged for months, and is sometimes exported in that form preserved in tigh f ly corked bottles. The tree, it is said, yields 196 ELEMENTARY CHEMISTRY. about a gill per day from each incision made. A little clay cup is placed underneath, from which the juice is collected and poured over clay or wooden patterns in successive layers as it dries. To hasten the process it is carried on over large open fires, the smoke of which gives to the rubber its black color ; when pure it is almost white. When nearly hard the rubber will receive any fanciful design which may be marked upon it with a pointed stick. The natives often form the clay into odd shapes as bot- tles, images, etc., and the rubber is sometimes ex- ported in these uncouth forms. The solvents of rubber are ether, naphtha, coal-oil, turpentine, ben- zole, etc. It melts, but does not become solid on cooling. It loses its elastic power when stretched for a long time, but recovers it on being heated. In the manufacture of rubber goods for suspenders, etc., the rubber thread is drawn over bobbins and left for some days until it becomes inelastic. In this state it is woven, after which a hot wheel is rolled over the cloth to restore the elasticity. VULCANIZED RUBBER is made by heating caout- chouc with a small amount of sulphur. This con- stituted Goodyear's original patent, and was dis- covered accidentally. While engaged in experi- menting upon improvements in this branch of manu- facture, he was one day talking with a friend and happened to drop a bit of sulphur in a pot of melted rubber. By one of those happy intu : tions which seem to come only to men of genius, he watched tho ORGANIC BASES. 197 result, and discovered " Vulcanized Eubber !" It is less liable to be hardened by cold or softened by heat, and admits of many uses to which common rubber would be entirely unsuited. When, in addi- tion, it is mixed with pitch and magnesia, it becomes a hard brittle solid, capable of a high polish, and is used for knife-handles, combs, and brushes. GUTTA-PERCHA resembles caoutchouc in its source, preparation, and appearance. It softens in warm water, and can then be moulded into any desired shape. When cooled it assumes its original solidity. It is extensively used in taking impressions of medals, etc. ORGANIC BASES The organic bases, or alkaloids, as they are called, are the bases of true salts found in plants. They dissolve slightly in HO, but freely in alcohol. They have a bitter taste, and rank among the most fearful poisons known. The antidote is tannin, which forms with them insoluble tannates. Any liquid contain- ing it is of value as strong green tea and should be immediately administered in a case of poisoning by any of the alkaloids. OPIUM is the dried juice of the poppy plant, which is extensively cultivated in Turkey for the sake of .this product. Workmen pass along the rows soon after 198 ELEMENTARY CHEMISTRY. the flowers have fallen off, cutting slightly each cap- sule. From this incision a milky juice exudes and collects into a little tear. In twenty-four hours these are gathered and beaten up in an earthen jar with saliva to the proper consistency, when the mass is wrapped in leaves for the market. It is afterward purified. Properties. Opium produces a powerful influence on the nervous system. It stimulates the brain and excites the imagination to a wonderful pitch of in- tensity. The dreams of the opium-eater are said to be vivid and fantastic beyond description.* The dose must be gradually increased to repeat the effect, and the result is most disastrous. The nervous system becomes deranged, and no relief can be secured save by a fresh resort to this baneful drug. Labor be- comes irksome, ordinary food distasteful, and racking pains torment the whole body. No person can be too careful in the use of a narcotic whose influence is liable to. become so destructive. OPIUM-SMOKING. In China the custom of smoking opium is fearfully prevalent. The opium is made into a thick syrup with water. A small portion is placed in the bowl of the pipe, which is held in the flame of an oil-lamp until the opium is partly vola- tilized and fully ignited. During this process, the smoker, reclining upon his side, gently inhales the fumes, and absorbs them by retaining them until they slowly pass out through the nose. Opium-shops OBGANIC BASES. 199 are said to be more numerous in China than even rice-shops. The effect is worse than that of intoxi- cating liquors, if it is possible to compare two such fearfully pernicious vices. MORPHIA. Morphine is one of the alkaloid bases of opium. It is so called from Morpheus, the god of sleep. It is a bitter, narcotic, resinous-like sub- stance. It is used principally as a sulphate of mor- phia, in doses of one-eighth to one-fourth of a grain, to alleviate pain and produce sleep. Laudanum is the tincture of opium. Paregoric is a camphorated tincture of opium, with benzoic acid and oil of anise. QUINIA. Quinine is prepared from Peruvian bark. It is employed in medicine as a tincture of Peruvian bark, or in the form of sulphate of quinia, for cases of fever and ague and all periodic diseases. NICOTINE is the active principle of the tobacco plant. It is volatile, and passes off in the smoke. A drop will kill a large dog. It probably produces the ill effects that follow the use of tobacco. STRYCHNIA. Strichnine is prepared from the nux vomica bean, obtained from a small tree in the East Indies. The "woorara," with which the South American Indians poison their arrows, is a variety of strychnine. This is so deadly that the scratch of a needle dipped in it would produce death. Strych- nine is scarcely soluble in water, but freely in the essential oils and chloroform. It is so intensely bitter that one grain will impart a flavor to twenty- 200 ELEMENTARY CHEMISTRY. five gallons of water. One-thirtieth of a grain has killed a dog in thirty seconds, while half a grain is fatal to a man. The Chromatic Test consists in placing on a clean porcelain plate a drop of the suspected liquid, a drop of SO 3 , and a crystal of bichromate of potassa. Mix the three very slowly with a clean glass rod. If there be any strychnine present, it will change the color into a beautiful violet tint, passing into a pale rose. It is, however, one of the most difficult poisons to detect. Arsenic was formerly used by the poisoner, but Marsh's test infallibly reveals its presence in the body of the victim, even after many years have elapsed. But the organic poisons are so easily acted upon by the fluids of the system, that in one case, though four grains were taken, and death ensued very quickly, yet the " chromatic test" failed to re- veal the presence of any strychnine in the stomach. However, the murderer is not to escape. This is the only poison except brucite (and that also is ex- tracted from nux vomica) that produces tetanus or lock-jaw. This symptom infallibly proves to the physician that death has been caused by strychnine. To prove this conclusively, a tiny frog is brought into the court-room and made to show the effects of the poison. So sensitive is this gentle reptile, that a few drops of oil containing only yo-o.V or ^ a g 1 *^ w ill instantly throw him into the most rigid locked-jaw, in which he is incapable of producing a single croak. COFFEINE AND THEiNE constitute the active prin- ORGANIC BASES. 201 ciple of tea and coffee, and are isomeric. They crys- tallize in beautiful white prisms of a silky lustre. In addition, tea contains from 12 to 18 per cent, of tannic acid, some 15 per cent, of gluten, which is lost in the " grounds" (unless we imitate the Japanese and eat them with the tea), and a volatile oil which gives to it its peculiar aromatic odor and taste. Coffee con- tains 14 per cent, of a fixed oil, and also an essential oil which is developed in roasting, and is remarkably volatile, so that it soon escapes unless the coffee is kept tightly covered. Tea-raising. The tea-plants are allowed to grow only about a foot and a half high, and resemble in some respects the low whortleberry bush. They are grown in rows, three to five in a hill, very much as corn is with us. The medium-sized leaves are picked by hand, the largest ones being left on the bushes to favor their growth. Each little hill or clump will furnish from three to five ounces of green leaves, or about one ounce of tea in the course of the sea- son. The leaves are first wilted in the sun, then trodden in baskets by barefooted men to break the stems, next rolled by the hands into a spiral shape, then left in a heap to heat again, and finally dried for the market. This constitutes BLACK TEA, and the color would be produced in any leaves left thus to wilt and heat in heaps in the open air. The Chinese always drink this kind of tea. They use no milk or sugar, and prepare it, not by steeping, but by pour- ing hot water on the tea and allowing it 'to stand for 202 ELEMENTABY CHEMISTRY. a few minutes. Whenever a friend calls on a China- man, common politeness requires that a cup of tea be immediately offered him. Green Tea is prepared like black, except that it is not allowed to wilt or heat, and is quickly dried over a fire. It is also very frequently, if not always, col- ored, cheap black teas and leaves of other plants being added in large quantities. In this country, damaged teas and the " grounds" left at hotels are re-rolled, highly colored, packed in old tea-chests, and sent out as new teas. Certain varieties of black tea even receive a coating of black-lead to make them shiny. There are various other alkaloids that are worthy of mention merely. Lettuce contains one similar to opium, which gives it a slight narcotic influence. Aconite is obtained from monk's-hood, veratrine from the hellebore, solanine from the henbane, pi- perine from white, black, and long peppers isomeric in white needle-shaped crystals. ORGANIC COLORING PRINCIPLES. With the exception of cochineal, all the organic coloring principles are of vegetable origin. The beautiful tints of flowers are so evanescent that they cannot be retained. Coloring matters are therefore taken of soberer hue from the interior of plants, where they are less exposed to the light. DYEING. Very few of the colors have such an ORGANIC COLORING PRINCIPLES. 203 affinity for the fibres of the cloth that they will not wash out. Such as, like indigo, will dye directly are called substantive colors. But the majority require a third substance which has an attraction for both the coloring matter and the cloth, and will hold them together. Such substances are called mordants (from mordeo, to bite), because they bite the color into the cloth. The most common mordants are alum, oxyd of tin, and copperas. In dyeing, the cloth is first dipped in a solution of the mordant, and then of the dye-stuff. Ex. : If a piece of cotton cloth be dipped in a decoction of madder, it will receive an unstable dirty red color. If, however, it be soaked first in a solution of alum and sugar of lead (PbO.A), the acetate of alumina will be formed in its fibres, and will act as a mordant. Now dip it into the same dye, and it will come out a brilliant red a " fast color." The mordant, by means of a stamp, may be applied to the cloth in the form of a pattern, and when it is afterward washed, the color will all be removed ex- cept where the mordant fixed it in the printed figure. The same dye will produce different colors by a change of mordants. Ex. : Logwood and copperas will dye black ; logwood and tin, a violet. Madder will dye in this way red, purple, yellow, orange, and brown. This principle lies at the basis of dyeing "prints." CALICO-PRINTING. A calico-printing machine is very complex. Tiie cloth passes between a series of rollers, upon which the corresponding, mordant is 204 ELEMENTAEY CHEMISTIiY. put, as ink is on type. A single machine sometimes prints from twenty sets of rollers ; yet each impres- sion follows the other so accurately, that when the cloth has passed through, the entire pattern is printed upon it with the different mordants more perfectly than any painter could do it, and so rapidly that a mile of cloth has been printed with four mordants in an hour. The cloth when it leaves the printing machine, though stamped with the mordants in the form of the figure, betrays nothing of the real design until after being dipped in the dye, which acting on the different mordants brings out the desired colors. The print is now washed, glazed, and fitted for the market. BED AND VIOLET COLORING SUBSTANCES. Madder is the root of a plant found in the East Indies. When first dug it is yellow, but by exposure to the air it absorbs O and becomes red. It is used in dyeing the brilliant Turkey-red. Cochineal is an insect that preys upon a species of cactus in Central America. It is raised in large plantations, dried between hot iron plates, and exported as an article of commerce. It yields the brightest scarlet and purple dyes. The purple of which we read in ancient writings was a secret with the Tyrians. King Huram, we learn, sent a workman to Solomon skilled in this art. The dye was obtained from a shell-fish that was found on the coast of Phoenicia. Each animal yielded a tiny drop of the precious liquid. A yard of cloth dipped twice in this costly dye was worth $150. ORGANIC COLORING PRINCIPLES. 205 Brazil-wood furnishes a red which is not very per- manent. It is used for making red ink. Experiment : Boil 2 oz. of Brazil-wood in a pint of HO for fif- teen minutes, then add a little gum-arabic and alum. BLUE COLORING SUBSTANCES. The indigo of com- merce is obtained from a bushy plant found in Asia. The juice is colorless, but by fermentation for some days, in vats of water, a yellow substance is formed, which by exposure to the air absorbs O, and changes to a deep blue. By any deoxydizing agent the color of indigo may be removed at pleasure. Example : Add to a test-tube of boiling HO, colored with a solution of indigo,* a drop of NO 5 . The blue color will instantly disappear. Litmm is obtained from certain kinds of lichens, which grow on the rocks along the coasts of France and England. The juice is colorless, like the other dye-plants, but assumes a rich purple blue by the addition of ammonia (NH 3 ). GREEN COLORING SUBSTANCE. Leaf-green, as found in plants, is a waxy substance, containing several coloring matters. It seems to lie in the cells of the leaf in minute crystals, and to be formed by the action of the sunbeam. Plants removed from a dark cellar to the open air grow green rapidly. * To make this solution, mix a little pulverized indigo into a paste with SOs. Let it stand a few days, then add HO at pleasure. 206 ELEMENTABY CHEMISTRY. ALBUMINOUS BODIES. The Albuminous bodies differ essentially from any yet named. They are far more complex in their structure, contain more nitrogen, and do not crys- tallize. The most important are Albumen, Fibrin, Casein. These are isomeric, and, when taken into the system, are all changed into albumen before leaving the stomach. When decomposed by an alkali they yield a white inodorous solid, which will act as a base and form salts. This is called "Protein" (proteuo, I am first), and these substances them- selves are termed the protein compounds. Their composition is very complex, as may be seen from the following table given by Liebig : Albumen of blood ) Albumen of flesh ( C 316 H m O 68 N a7 S a . Fibrin of flesh ) Albumen of eggs C 216 H m O C8 N 87 S,. Casein C a88 H aa8 O, N M S a . Fibrin of blood C 998 H aa8 O M N 40 S a . ALBUMEN. Sources. It exists nearly pure in the whites of eggs hence the name (albus, white) ; also in the serum the transparent part of the blood and the juices and seeds of many plants. Properties. It is soluble in cold, but insoluble in ALBUMINOUS BODIES. 207 hot HO. At a temperature of 145 F. it coagulates. This change we always see in the cooking of eggs. Alcohol, corrosive sublimate, acids, creosote, etc., have the power to coagulate albumen. In cases of poisoning by these substances it is therefore a valu- able antidote, as it wraps them up in an insoluble covering, and so protects the stomach. Albumen seems to have the properties of an acid and a base. It coagulates with an acid by uniting with it as a base. It coagulates with a salt by uniting with its base as an acid. It exists in two amorphous condi- tions as a liquid in the sap of plants, the humors of the eye, serum of blood, etc.; as a solid in the seeds of plants and the nerves and brains of ani- mals. Vegetable Albumen. If the water used in making starch from potatoes be boiled, it will become tur- bid and deposit a flaky white substance identical with the whites of eggs, and therefore named vege- table albumen. FIBRIN constitutes chiefly the fibrous portion of the muscles. If a piece of lean beef be washed in clean HO until all the red color disappears, the mass of white tissue which will remain is called fibrin. Like albumen, it exists in two forms as a liquid in the blood, and as a solid n , , ., , Fibrin, or Muscle. in flesh and the seeds 203 ELEMENTARY CHEMI8TEY. % of plants. The clotting of blood is due to the coagu- lation of the fibrin. Vegetable Fibrin Gluten. If wheat flour be made into a dough, and then kneaded in water until all the soluble portion is washed away, the tough glu- tinous mass which will remain is called gluten. It is identical in composition with fibrin, and is there- fore named vegetable fibrin. We obtain it as a gum when we chew wheat, thereby dissolving the starch. It exists most abundantly in the bran of cereal grains. Example : "Wheat. CASEIN is found in the curd of milk (whence the name, caseum, cheese), in the blood, peas, and beans. The curdling of milk is due to the coagulation of its casein. When milk sours, its lactic acid com- bines with the alkali present, and precipitates the casein, which is only soluble in HO containing some alkali. The rennet (the dried stomach of a calf), used in making cheese, acts in the same manner. Vegetable Casein. By treating peas as we do pota- toes in forming starch, and then adding a little acid to the water which is left after the starch settles, an albuminous substance is deposited, which is identical with casein, and has received the name vegetable casein. The Chinese use it largely for cheese. GELATIN. Hot water dissolves a substance from animal membranes, skin, tendons, and bones, which, on cooling, forms a yielding tremulous mass called gelatin. As calves-foot jelly, soups, etc., it is well known. As an article of food it is of very little nu- ALBUMINOUS BODIES. 209 tritive value. It may answer to dilute a stronger diet, but of itself does little to build up the body of an invalid. Beef-tea is by far more strengthening than jellies or blanc-mange. Glue is a gelatin made from bones, hoofs, horns, etc., by boiling in HO and then evaporating the solution. Isinglass is the purest gelatin, and is obtained from the air-bladders of the cod, sturgeon, and other fish. Size is gelatin prepared from the parings of parchment, the thin- nest kind of skins. It is used for sizing paper to fill up the pores and prevent the ink fr, m spreading, as it does on unsized or blotting-paper. Vegetable Gelatine is familiar to us in the form of blanc-mange and the fruit-jellies. It is nearly like starch or grape-sugar in its composition. It is called Pectine (see page 159). It is found in Ice- land moss, grapes, apples, quinces, and other fruits. MILK is a natural emulsion, composed of exceed- ingly minute globules diffused through a transparent liquid. The globules consist of a thin envelope of casein filled with butter. Being a trifle lighter than HO, they rise to the surface as cream. Churning breaks these cover- ings, and gathers the butter in- to a mass. Milk contains some sugar, and this, by the action of Milk under Microscope. the O of the air changes to lactic acid, which gives the peculiar taste to sour milk. The casein seems to act as a ferment in hastening this oxydation. In 210 ELEMENTAKY CHEMISTRY. churning, the cream always " turns," because O is rapidly absorbed as the milk is stirred, and lactic acid formed. Milk sours in the stomach by the action of the acids, which convert it into lactic acid. BONES consist of organic and mineral matter com- bined. ANALYSIS. (Berzelius.} Gelatin (Gluten) 32.17 Blood-vessels 1 . 13 Phosphate of lime 51 .04 Carbonate of lime 11 .30 Fluoride of calcium 2 . 00 Phosphate of magnesia 1.16 Chloride of sodium 1 .20 100.00 By soaking a bone in HC1 the mineral matters will all be dissolved, and the organic matter left in the original shape of the bone, but soft and pliable. If, instead, the bone be burned in the fire, the organic matter will be removed and the mineral left white and porous. The blood circulates freely through the bones, however hard they may seem to be. If a little madder be mixed with the food of pigs, it will tinge red all their bones. If the madder be given at considerable intervals, it will make streaks of white and red bone alternately. Putrefaction. Owing to the complex structure of albuminous substances, and the presence of the fickle ALBUMINOUS BODIES. 211 nitrogen, they readily oxydize and form entirely new compounds. This breaking up is called putre- faction. The P and S present in flesh especially, take up the H in hot haste, and flying off as sul- phuretted hydrogen (HS) and phosphuretted hydro- gen (PH 3 ), salute our olfactories with their well- known odors. These poisonous and offensive gases abounding near slaughter-houses and similar estab- lishments, make them so unhealthy. Any portion of an albuminous substance thus putrefying may act as a ferment. This probably explains the danger physicians incur in dissecting a dead body. The least portion of the decomposing matter enter- ing their flesh, through a scratch even, is liable to be fatal. The presence of an albuminous substance always hastens decay. The white, or sap wood, contains some N, and so this rots very quickly. Timber steeped in a solution of corrosive sublimate (kyanized) is rendered almost indestructible, because that salt coagulates the albumen. The absence of HO retards chemical change, and therefore meats, apples, etc., are preserved by drying. Salt acts somewhat in the same way by absorbing the juice of the meat, and, while it covers it as brine, wards off the attacking O ; but as it dissolves some of the salts and other valuable elements of the meat, it makes it less nutritious. 212 ELEMENTARY CHEMISTBY. DOMESTIC CHEMISTKY. In the chemistry of housekeeping there are some points not yet spoken of, and they may now be prof- itably discussed. MAKING BREAD. Flour consists of gluten, starch, and a little gum and sugar. There is also about two per cent, of ash, about one half of which is phos- phate of lime; but these mineral constituents are found mainly in the bran. In mixing the " sponge," the process is purely mechanical. The water used moistens the starch, dissolves the albumen, sugar, and gum, and causes the gluten to cohere. When the sponge is set aside in a warm place to rise (as heat favors chemical change), the yeast, yeast-cake, or emptyings, as the case may be, induces a rapid fermentation, converting the sugar into alcohol and CO 2 . This gas is diffused through the mass, and struggles to escape, but is retained by the tenacious and viscid dough, causing it to "rise." The next step includes the addition of fresh flour, and a la- borious process of " kneading." The latter, so essen- tial to good bread, diffuses the half-fermented sponge uniformly through the dough, and thus spreads the continued fermentation throughout the loaf ; it also breaks up into smaller ones the bubbles of gas en- tangled in the gluten, and thereby makes the bread DOMESTIC CHEMISTRY. 213 fine-grained. The dough is now "moulded" into loaves. When placed in the hot oven, the first effect is to increase the fermentation. Some of the starch is turned into sugar to supply material, the heat ex- pands the CO 2 , changes the alcohol to vapor and the water to steam. All these by their expansive force rapidly increase the size of the loaf. When the whole loaf has been heated to about 350 F., the fer- mentation is checked, and if the temperature of the oven is right, the cells of the bread will have suffi- cient strength to retain their form after the gas and vapors have escaped. If the heat is not sufficient, or if there is too much water in the dough, the CO 2 escapes, and the cells, not having hardened suffi- ciently, collapse, and the bread is "slack-baked." If the oven is too hot, a crust forms over the surface of the loaf, which prevents the escape of the CO 2 , so it accumulates at the centre, making the bread hollow. A part of the starch in the crust is con- verted by the heat into gum (dextrine), and if it be burnt, this is disorganized, the volatile gases driven off, and the carbon left. A shiny coat is given to the loaf ("rusk") by moistening the crust after the bread is baked, thus dissolving some of the gum, which quickly dries on returning it to the oven. Milk-emptyings is sometimes used in making bread. In this case, the mixture of flour and milk, kept at a temperature of 90, develops yeast, which produces fermentation. If the heat is over 90, the yeast plant is killed ; if lower, it is not formed. In the 214 ELEMENTARY CHEMISTRY. latter case, the milk is merely turned to lactic acid. Oftentimes, too, the side of the dish, near the fire, may be warm enough to produce yeast and to gen- erate CO 2 and alcohol, while on the opposite side lactic acid is being formed. A uniform temperature is necessary, and this can best be obtained by pla- cing the dish of emptyings in a kettle of warm water on the stove hearth, where the temperature can be kept very near the requisite 90. STALE BREAD. New bread consists of nearly one half water. In stale bread this disappears. It has, however, only combined with the solid portions chemically, and may be brought to view by heating the loaf in a close tin vessel. AERATED BREAD is not " raised" by fermentation, but by means of CO 2 , which is forced into it by great pressure. SOUR BREAD is caused by the first stage of the fermentation not being stopped soon enough, and the second stage commencing, in which acetic acid is formed. This may be neutralized by an alkali, as saleratus (KO.2CO 2 ), or soda (NaO.2CO 2 ). PAN-CAKES are raised by the addition of some fer- ment, as yeast, but the second, or acetous stage, is always reached. The " batter" now tastes sour, #nd is sweetened by saleratus or soda. The acetic acid combines with the KO (if saleratus is used), forming acetate of potassa, a neutral salt which remains, and the CO 2 bubbles up through the batter, making it "light." DOMESTIC CHEMISTRY. 215 EAISING BISCUIT. In raising biscuit or cake, soda and cream of tartar are most commonly used. The latter is a bitartrate of potassa, and the reaction is as follows : Na0.2CO 2 + K0.2T Cream of tartar is now often adulterated with plaster, lime, chalk, or flour. By dissolving in water these can be detected, as they form an insoluble precipi- tate ; but in milk, as commonly used in cooking, they are not noticed. Common "baking-powders" contain simply cream of tartar and soda. Professor Hosford's powders are scientific. They contain phosphate of lime and soda. The reaction is the same as that just described, while phosphates of lime and soda are formed, both of which are materials for bone-making. Soda and HC1 are also used in bak- ing. By heat both constituents are resolved into HO, CO 2 , and NaCl. The HO and CO 2 raise the bread, while the common salt seasons it. There is a difficulty in procuring pure acid and in mixing the ingredients in their combining proportions. Bread Dietetics. It is doubtful whether ordinary yeast-powders or cream of tartar and soda make as healthy food as the regular process of fermentation. There is frequently a portion of the powders left un- 216 ELEMENTARY CHEMISTRY. combined, and always a salt formed which may in- jure the gastric juice. Sometimes, indeed, we find biscuit and cake yellow, and even spotted with bits of saleratus ; yet such food must be " eaten to save it." A most wretched mistake ! Better throw away pans of cake and biscuit than torment Nature with such nauseous, poisonous preparations. Sal-volatile or carbonate of ammonia is often used by bakers for raising cake. This should volatilize into two gases, NH 3 and CO 2 , on the application of heat, but in prac- tice a portion is left commonly hidden in the cake to work injury to the inoffensive stomach. TOASTING BREAD. By toasting bread it becomes much more digestible, as the starch is converted largely into gum, which is soluble. The charcoal which may be formed when the heat has disorgan- ized the bread and driven off the water, also acts favorably on the stomach by absorbing in its pores noxious gases, as in " crust coffee." COOKING POTATOES. A raw potato is indigestible, but by cooking, the starch granules absorb the water of the potatoe, burst, and make it " mealy." If the potatoe contains more HO than the starch can im- bibe, it is called " watery." COOKING MEAT. All fried food is unhealthy, since the fat is partly disorganized by the heat, and there- fore becomes rancid on the stomach. Broiling and boiling are the most preferable methods of cooking. In the former no butter should be used, and the juices should not be pressed out of the meat, but the heat DOMESTIC CHEMISTRY. 217 should be intense enough to sear over the outside instantly, and prevent " dripping" on the coals. In the latter, the water should boil when the meat is put in, so as to coagulate the albumen upon the out- side, close the pores, and thus keep the juices of the meat within, otherwise it will become tough, and much also of its value will be lost. In making soup, on the contrary, as the object is to extract the juices of the meat, cold water should be used. It should be heated slowly, and boiled only for a few moments just before it is taken off from the fire. Long con- tinued boiling would coagulate that which should remain dissolved in the soup. In baking, the oven should be very hot at first, to prevent the meat from becoming dry and unsavory. When meat burns, the heat has become so intense as to disorganize the flesh, driving off the HO and volatile gases, and leaving the C. WATER IN COOKING. The solvent power of soft water is greater than that of hard water. For this reason, in making soup, tea, etc., the former should be used ; in boiling meats and cooking vegetables, where the object is not to extract the flavor or juices, the latter is preferable. Sometimes in cooking very delicate vegetables, as onions, the hardness of the water must be increased by adding salt to prevent their sweetness from dissolving. Salt is not put into vegetables, when boiling them, so much to flavor them as to preserve their aroma, which, if lost, no subse- quent salting will restore. Peas and beans will not 10 218 ELEMENTARY CHEMISTRY. cook soft in hard water, because the mineral matter hardens the casein they contain. A soup cannot be made of salt meat. QUANTITY or FOOD EEQUIRED. To repair the con- stant waste of the body, we each require about 800 Ibs. of food, 1500 of water, and 800 of oxygen per annum. A ton and a half of material is thus needed each year to preserve intact our corporeal system. We take in each day about 10 Ibs. of matter, yet may not gain an ounce in weight. This large amount passing through the mould of our body is all burned i. e., combines with O. This must be a renewed proof of the statement made under the sub- ject of oxygen, that the vital principle does not pre- vent decay, but only regulates it, and that the moment we begin to live we begin to die. THE EFFECT OF FOOD. There is an ancient saying, " Tell me what a man eats and I will tell you what he is." A man's nvnd sympathizes so intimately with his body, that through the body the soul itself may be gradually animalized by gross food. The coarse feeder and the fine feeder become as different in their feelings as they are in their food. Aninml food inflames ; vegetable, calms. The passionate re- quire a vegetable diet, while the phlegmatic may stimulate with flesh. Compare, for example, the dreamy vegetarian H:'ndoo with the fierce, meat- eating Indian. THE DIVISIO so 7 R) D. All food is divided into two . general classes" ; ext-malwng" and " muscle-' DOMESTIC CHEMISTRY. '219 making" or respiratory and nutritive. The former comprises all such articles as are burned in our cor- poreal stove, as wood is in a furnace, mainly to pro- duce heat. Example : Alcohol, starch, sugar, gum, fat, butter, etc. The latter includes such as are transformed into flesh and bone, and thus build up our bodies in some manner. Example : Lean meat, bread, milk, etc. Each of these contains a mixture of both to a certain extent, but is mainly either respiratory or nutritive. Example : Fat is deposit- ed in cells which are probably nutritive, and, on the other hand, bread contains starch, which is respira- tory. NUTRITIVE YALUE OF FOOD OF DIFFERENT KINDS. The following table, from Liebig, illustrates this sub- ject : Nutritive. Respiratory. Cows' milk 1 3. Beans 1 2.2 Peas 1 2.3 Fat mutton 1 2.7 Fat pork 1 3. Beef 1 1.7 Veal 1 .1 Wheat flour 1 4.6 Oatmeal 1 5. Rye flour 1 5.7 Barley 1 5.7 Potatoes (white) 1 8.6 Potatoes (blue) 1 11.5 Rice 1 12.3 Buckwheat 1 13. Sugar, alcohol, oil, etc., are heating and fattening. .They make no. muscle, no brain, no nervous tissue. 220 ELEMENTARY CHEMISTRY. The bran of wheat contains largely the mineral mat- ter we need for our bones and teeth and the nutri- tive food for our muscles. The whiteness of fine flour (" bolted" from its bran) is given to it by its starch. Our bones and muscles call loudly for the flour unbolted, as Nature designed it to meet our wants. Pork is only half as nutritious as beef, and is hence worth for work only half price. Besides, the hog is a filthy animal, a gross feeder, and sub- ject to so many cutaneous diseases, that he will even stop eating for the luxury of being scratched. Its flesh was doubtless never designed for Yankee any more than for Jew. The workman gains strength, not from the pork he eats, but the turnips, cabbage (in its composition so near to beefsteak), milk, eggs, and other plastic or nutritive food. CLIMATE PRESCRIBES THE KIND OF FOOD. The Es- quimaux Indian, with a climate many degrees be- low zero, needs much fire in his stove ; so he lives mainly qn fats. Tallow candles constitute his sweet- meats twelve pounds making a luxurious dessert. Dr. Kane tells us that they would steal the half-burned wicks out of his candlesticks and draw them slowly between their teeth, to secure the adhering grease. Indeed, their idea of heaven is said to be that there the righteous will live in ice-huts, and feast forever on blubber. An American living in the Arctic regions soon acquires much of an Esquimaux's love for fats and oils. Nature has providentially provided there that kind of food, and not much else. Turn now to DOMESTIC CHEMISTRY. 221 the tropics, where the temperature is so high that all one's attention is taken up in keeping cool, and we find an entire change in the diet of the inhabitants. The natives confine themselves almost entirely to vegetables, and with this watery fuel reduce the heat of their bodies to the lowest point. A MIXED DIET REQUIRED. Nature seems to pre- scribe a mixed diet, to supply both wants of the system, and has, to some extent, mixed them her- self in the various kinds of food. The Frenchman eats oil on his salad, the Yankee bakes beans with his pork, the Italian begs a bit of cheese for his maccaroni, the Irishman drinks buttermilk with his potatoes, the Hindoo pours rancid butter on his rice, while the Chinaman seasons his with pea cheese. No amount of starch or fat would support life. A man would starve on sugar or butter alone. The nitrogenous or nutritive element must be added. The season also regulates our diet. In the winter the highly respiratory buckwheat, with butter and syrup, is perfectly palatable, while in summer acid drinks, watery vegetables, and a simple unstimula- ting diet is equally enjoyed. 222 ELEMENTARY CHEMISTRY. CONCLUSION. CHEMISTRY OF THE SUNBEAM. All those various plant products of which we have spoken in Organic Chemistry, when burned, either in the body as food or in the air as fuel, give off heat. This was garnered in the plant while growing, and came from that great source of heat the sun. Thus all vegetation contains the latent heat of the sunbeam, ready to be set free upon its own oxydation. The coal even, de- rived as it is from ancient vegetation, hidden away in the earth, is thus a mine of reserved force. Those black diamonds we use as fuel become, in the eye of science, crystallized sunbeams, fagots of force, ready to impart to us at any moment the heat of some old carboniferous day. As we warm ourselves by our fires, or sit and read by our oil and gas lights, how strange the thought that their light and heat streamed down upon the earth ages ago, were ab- sorbed by those grotesque leaves of the old coal forests, and kept safely stored away by a Divine care, in order to provide for our comfort ! To carry the idea still further, we see that the present warmth of our bodies all comes from the same source the sun. It mostly fell in the sunbeams of last summer upon our gardens and fields, was preserved in the CONCLUSION. 223 potatoes, cabbage, corn, etc., we have eaten, as fuel, and to-day reappears as heat and motion. CHANGES OF MATTER. Chemical changes are taking place wherever we look on land or sea. The hard granite crumbles and moulders into dust. The stout oak takes in the air and solidifies it ; takes up the earth and vitalizes it ; changes all into its own struc- ture, and proudly stands monarch of the forest. But in time its leaves turn yellow and sere, its branches crumble, itself totters, falls, and disappears. Our own bodies seem to us comparatively stable, but, with the rock and the oak, they too pass away. All Nature is a torrent of ceaseless change. We are but parts of a grand system, and the elements we use are not our own. The water we drink and the food we eat to-day may have been used a thousand times before, and that by the vilest beggar or the dirtiest earth-worm. In Nature all is common, and no use is base. She keeps no selected elements done up in gilt papers for sensitive people. Those particles of matter we so fondly call our own, and decorate so carefully, a few months hence may have dragged boats on the canal, or waved in the meadow as grass or corn. From us they will pass on their ceaseless round to develop other forms of vegeta- tion and life, whereby the same atom may freeze on arctic snows, bleach on torrid plains, be beauty in the poet's brain, strength in the blacksmith's arm, or beef on the butcher's block. Hamlet must have been somewhat more of a chemist than a madman 224 ELEMENTARY CHEMISTEY. when lie gravely assured the king that " man may fish with the worm that hath eat of a king, and eat of the fish that hath fed of the worm." Life and death are thus, throughout Nature, commensurate with and companions of each other. Oxygen is the destroyer. It tears down every living structure, and would bring all things to rest in ashes. The sun- beam is its antagonist. It rebuilds and reinvigor- ates. THE SUN THE SOURCE OF POWER. The sun warms, enlivens, and animates the earth. In the laboratory of the leaf it works the most wonderful chemical changes. We see its handiwork in the building of the forest, the carpeting of the meadow, and the tinting of the rose. On the ladder of the sunbeam water climbs to the sky, and falls again as rain. The very thunder of Niagara is but the sudden un- bending of the spring that was first coiled by the sun in the evaporation from the ocean. Up to the sun, then, we trace all the hidden manifestations of power. Yet the force that produces such intricate and wide-extended changes is but one twenty-three hundred millionth part of the tide that flows in every direction from this great central orb. But what is our sun itself save a twinkling star beside great suns like Sirius, and Eegulus, and Procyon, whose brilliancy in the far-off regions of space drowns our little sun as the dazzling light of day does the smouldering blaze of some wandering hunter? CONCLUSION. 225 Thus have we traced some of the wonderful pro- cesses by which this world has been arranged to supply the varied wants of man. Wherever we have turned, we have found proofs of a Divine care plan- ning, conforming, and directing to one universal end, while from the commonest things and by the simplest means the grandest results have been attained. Thus does Nature attest the sublime truth of Revelation, that in all, and through all, and over all, the Lord God omnipotent reigneth. 10* APPENDIX. PEOBLEMS. MATHEMATICS OF CHEMISTRY. In solving the prob- lems given on the 17th page, some may prefer to use proportion. The following will suggest the method : The equivalent tf the given constituent : equivalent of the compound : : weight of tht> constituent : weight of the compound. Problem 1. How many Ibs, of HO are there in a cwt. ofS0 3 .2HO? Solution 2HO = 18 = equivalent of the given constituent. S0 3 . 2HO = 58 = equivalent of the compound. x = weight of the constituent. 100 Ibs. = weight of the compound. 18 : 58 : : x : 100 Ibs. x = 31^ Ibs. Prob. 2. How much sodium is there in 20 gr. of sal-soda (NaO,CO ? )? 228 ELEMENTARY CHEMISTBY. Solution Na = 23 = equivalent of the given constituent. NaO = 31 = equivalent of the compound. x = weight of the constituent. 20 gr. = weight of the compound. ' 23 : 31 :: x : 20 gr. Prob. 3. How much carbonate of lime can be formed from one drachm of C? Solution C = 6 = equivalent of the given constituent. CaO.CO 2 = 50 = " " " compound. 1 dr. = weight of the given constituent. x weight of the compound. 6 : 50 : : 1 dr. : x. x = 8| drachms. Prob. 4. How much C0 2 would be required to neutralize 2 Ibs. of potash ? Solution. First we find how much KO.CO 2 two Ibs. of KO will make, and then how much C0 2 will be contained in that amount of the salt. (1.) KO = 47 = equivalent of the constituent. KO . CO 2 = 69 = equivalent of the compound. 2 Ibs. = weight of the constituent. x = weight of the compound. 47 : 69 :: 2 Ibs. : x = Sftlbs. = weight of KO.CO,. APPENDIX. 229 (2.) CO 2 = 22 = equivalent of the constituent. KO.C0 2 * = 69 = equivalent of the compound. x = weight of the constituent. 24 = weight of the compound. 22 : 69 :: x : 2ff-lbs. The remaining problems can be used throughout the term at the discretion of the teacher, whenever the appropriate subject is under consideration in the class. Prob. 5. What weight of is contained in 60 gr. ofKO.C10 5 ? Prob. 6. How much KC1 will be formed in prepar- ing 80 gr. of O ? Prob. 7. How much H can be made from 10 Ibs. of Zn? Prob. 8. How much H can be made from 50 Ibs. of water? Prob. 9. How much saltpetre will be required to make 18 Ibs. of aquafortis ? Prob. 10. How much oil of vitriol will be required 4o decompose 6 Ibs. of saltpetre ? Prob. 11. How much HO will be decomposed by one drachm of K, and how much KO will be formed ? Prob. 12. What weight of nitrous oxyd will be formed from the decomposition of 6 oz. of nitrate of ammonia? Prob. 13. How much sal-ammoniac would be re- quired to make 2 Ibs. of NH 3 ? * Some late authorities give the equivalent of K as 39.2, which would alight! v change tlii? result. 230 ELEMENTARY CHEMISTRY. Prob. 14. How much CO 2 will be formed in the combustion of 30 gr. of CO ? Prob. 15. What weight of carbonate of soda would be required to evolve 12 Ibs. of CO 2 ? Prob. 16. What weight of bicarbonate of soda (NaO.2CO 2 , "soda") would evolve 12 Ibs. of CO 2 ? Prob. 17. What weight of C is there in a ton of CO 2 ? Prob. 18. How much O is consumed in burning a ton of C? Prob. 19. In burning a charge of 10 Ibs. of gun- powder, find the weight of the several products formed. Prob. 20. What weight of common salt would be required to form 25 Ibs. of muriatic acid (HC1) ? Prob. 21. HC1 of a specific gravity of 1.2 contains about 40 per cent, of the acid. This is very strong commercial acid. What weight of this acid could be formed by the HC1 acid gas produced in the re- action named in the preceding problem ? Prob. 22. What weight of hydriodic acid (HI) is formed from a drachm of iodine ? Prob. 23. What weight of Glauber salts can be formed from 100 Ibs. of oil of vitriol ? Prob. 24. What weight of S is there in 10 gr. of sulphide of hydrogen? Prob. 25. How much O is required to change a Ib. of SO 2 toS0 3 ? Prob. 26. How much phosphorus in 40 Ibs. of phosphate of lime? . ....- APPENDIX. 231 Prob. 27. How much P in 40 Ibs. of the super- phosphate of lime? Prob. 28. How much phosphate of lime will an oz. of P make ? Prob. 29. How many Ibs. of HO in 186 Ibs. of S0 3 .3HO? Prob. 30. How much CO 2 is formed in the com- bustion of one ton of C ? Prob. 31. What weight of S is there in a ton of iron pyrites ? Prob. 32. What weight of copperas could be made from 500 Ibs. of iron pyrites ? Prob. 33. What weight of H is there in a pound of heavy carburetted hydrogen ? Prob. 34. How much O would be required to oxyd- ize the metallic copper which could be reduced from its oxyd by passing over it, when white-hot, 20 gr. of Hgas? Prob. 35. How much O would be required to oxydize the metallic iron which could be reduced in the same manner by 10 gr. of H gas ? Prob. 36. What weight of N is there in 10 Ibs. of NH 3 .HO? Prob. 37. How much KO . C1O 5 would be required to evolve sufficient O to burn the H produced by the decomposition of 2 Ibs. of HO ? Prob. 38. How much H must be burned to pro- duce a ton of water ? Prob. 39. How much S is there in a Ib. of S0 2 ? 232 ELEMENTARY CHEMISTRY. THE ALKALIES. Problem 40. As soda is used so extensively in the arts, it is of great importance to all consumers of soap, glass, etc., that it should be manufactured as cheaply as possible. Leblanc's process of making it from common salt is now universally adopted. The operation comprises two stages : (1) Changing common salt into sulphate of soda ; and (2), the changing of this sulphate of soda into carbonate of soda. The first operation is performed in large cast-iron pans, about 12 inches deep at the centre, and 9 feet diameter. A charge of 500 Ibs. of salt is thrown into one of t,hese pans with about an equal weight of SO 3 , and heated. The sulphate of soda is formed with an evolution of HC1 fumes. These fumes are conducted into the bottom of a vertical flue, filled with pieces of coke, wet with constantly dripping water. This HO absorbs the gas, and forms a very weak muriatic add, in immense quantities. The second stage consists in grinding the Glauber salts (sulphate of soda) with an equal weight of chalk (CaO. C0 2 ), and half its weight of coal. This mixture is heated and stirred until well melted, when it is raked out to cool. This mass is called " black ash" The chemical change that has taken place is very simple; the charcoal deoxydized the salts, changing the sulphate of soda into the sulphuret of sodium. The sulphuret of sodium then reacted with APPENDIX. 233 the carbonate of lime forming the sulphuret of cal- cium and the carbonate of soda, as follows : NaS + CaO.CO 2 = CaS + NaO.CO 2 . The carbonate of soda alone being soluble in HO, is dissolved out of the black ash, and then crystal- lized, producing the soda-ash of commerce. The muriatic acid, which is an incidental product of the first stage, is used in making chloride of lime, so extensirely employed in bleaching. The sulphuret of sodium has always been a waste product ; but at the late exposition at Paris (1867), blocks of sulphur, of tons weight each, were exhibited, which had been extracted from it by a process not yet divulged. It is said that 200,000 tons of common salt are annually used in the alkali manufactories of England. Find how much "soda" is formed from 500 Ibs. of salt. Prob. 41. Find the amount of Glauber salts pro- duced in the first step, with the charge just named. Prob. 42. Find the amount of HC1 produced. Prob. 43. Find how much sulphuret of sodium is formed in the second step. Prob. 44. Find how much sulphuret of calcium is made. Prob. 45. Find how much sulphur could be saved (if none were lost) from the CaS. Prob. 46. How many Ibs. of HC1 would be required to neutralize sufficient carbonate of ammonia to form a 30 Ib. cake of sal-ammoniac (NH 4 . Cl) ? 234 ELEMENTARY CHEMISTRY. Prob. 47. How much S is there in a ton of plaster (gypsum)? Prob. 48. How much aluminum is there in a ton of clay? Prob. 49. How much K is there in 10 Ibs. of alum? Prob. 50. How much white-lead (PbO . CO 2 ) could be made from a Ib. of litharge ? Prob. 51. How many Ibs. of C would be required to reduce 40 tons of brown Hematite (2Fe 2 O 3 . 3HO) ? Prob. 52. In 60 Ibs. of heavy spar (sulphate of baryta) how much S is there ? Prob. 53. How much alum can be made from 1 cwt. of potash? THE METALLOIDS. (Page 18.) OXYGEN. In making this gas, a cop- per flask and rubber tubing should be used, as it is by far the cheapest apparatus. Great care should be a Copper retort. b A copper tube leading from it. c Tube of india-rubber to convey the gas to a gas-bag, gasometer, or pneumatic trough. d GHS-bag. Spirit-lamp. APPENDIX. 235 taken in pulverizing the KO, C1O 5 , as a pressure of more than 10 Ibs. is liable to produce an explosion. For the experiments with the watch-spring, phos- phorus, etc., common "specie jars" will be found very convenient, or, in necessity, any wide-mouthed bottles which can be obtained of a druggist. The author will be pleased to correspond with any teacher who may be desirous of information concerning the apparatus which is needed, and the simplest method of performing the various experiments. Priced lists of apparatus, chemicals, etc., can be obtained, on application, from Messrs. J. Nellegar & Co. (late Messrs. Dexter & Nellegar), Albany, N. Y. (Page 34.) NITROUS OXYD. A special apparatus is necessary both for preparing and inhaling this gas safely. This consists of a glass retort as shown in the cut a wash-bottle, and in addition a gas-bag of from 20 to 50 galls, capacity for storing the gas, and a smaller bag of from 3 to 5 galls., with a wide, wooden mouth-piece for inhalation. It is well to pass the gas through a large wash-bottle, as shown in the cut on page 41, half full of HO, thence by a rubber tube directly into the large gas-bag. Before making the gas, pour into the bag a couple of gallons of HO : by standing in the bag over this the gas will be purifi d in a few hours. When about to admin- ister the gas, let the subject grasp his nose firmly between his thumb and forefinger: then, inserting the wooden mouth-piece, be careful that he does not inhale any of the external air, but takes full, deep 236 ELEMENTARY CHEMISTKY. breaths in and out of the gas-bag. Watch the eye of xthe subject, and notice the influence of the gas. Commonly, the best effect is not reached until he begins to surge backward and forward. (Page 43.) The zinc for making hydrogen should be granulated. This is easily effected by pouring the melted metal slowly from the ladle into a basin of HO. A common junk-bottle, fitted with a cork and a glass tube, will answer for the evolution of the gas, but a " hydrogen generator," as sold by appa- ratus dealers, is much more satisfactory. In experi- Hydrogen Generator. menting with H, great care must be used not to ignite the jet of gas until all the common air has passed out of the flask ; otherwise a severe explosion will ensue. It is a safe precaution to test the gas by passing it in bubbles up through HO, and igniting them at the surface; the force of the combustion will indicate if there be any danger. It must not be kept for any great length of time in bags, as the air will gradually force itself in, and the gas will APPENDIX. 237 partly pass out by the law of diffusion, thus form- ing a mixture which it is dangerous to ignite. The adjoining illustration of a jet of burning H is a representation of what is called " The Philosopher's Lamp." In using the " mixed gases," the utmost care is requi- site. The gases may be passed into a gas-bag, made of a common bladder, furnished with a stop-cock. A clay to- bacco pipe may be attached to it by means of a bit of rubber tubing. A plate of good soapsuds makes the outfit complete. Blow the bubbles with the gases in the bag, either in the air, or on the tin plate, but be cautious not to ignite them until the stop-cock is turned, and the bag withdrawn from the dish. Pure H bubbles may be blown in the same manner : if out of doors, they will float off to a great distance. H may be better purified for inhaling, by passing it through a solution of potash, with some alcohol added to it. The action of platinum sponge is best shown by the instru- ment represented in the cut. It was formerly used by chemists as a con- venient way of obtaining a light in the laboratory. Friction matches have superseded such clumsy inventions. The experiments with the compound blowpipe, as Shown in the frontispiece, Dobereiner'e Lamp. 238 ELEMENTARY CHEMISTRY. can be given either by the use of gasometers, or, in their stead, rubber gas-bags may be substituted at a much lower price. The H gun which is simply a tin tube, closed at one end, and provided with a cork at the other, having a priming-hole at the side may be filled over the Philosopher's Lamp when not ignited. The gas is al- low'ed to pass in until the gun is about a fifth full, as nearly as one can guess. Some teachers will pre- fer to use the more exact chemical term " molecule," when speaking of a com- pound, to the word " atom," as employed in the text. Molecule means the smallest quantity of a compound that can exist by itself. Thus the exact language of such would be "An atom of H and one of O unite, and form a molecule of HO." This term can be substituted very easily by those who desire it. The author has not employed it, lest he might con- fuse some beginners by an unnecessary scientific term. (Page 47.) WATER is analyzed by the action of the galvanic current in the manner shown in the fol- lowing cut. We analyze it when we put upon our coal Gasometer. APPENDIX. fire cinders wet with HO. The HO adds to the inten- sity of the fire, and " makes it burn better," as we say. (Page 55.) THE DIAMOND. Although the diamond is simply pure carbon, yet it has never been made Analysis of water. by any chemical process. Minute diamonds, it is said, have been separated from carbon compounds by long-continued voltaic action, but they were in- visible except by a microscope. The value of the diamond varies with the market ; the general rule is as follows : a gem ready for setting, of one carat weight, is worth $40 to $60 ; beyond this size, its value increases according to the square of its weight. The Kohinoor (mountain of light) weighs 103 carats, and is valued at $10,000,000. (Page 64.) CARBONIC ACID. The experiments with this gas may be still further varied by having at the bottom of the inclined plane shown in the cut on page 65, a light model of a water-wheel. The invisible gas flowing down-hill will turn it very freely, especially if too many candles are not burn- ing at the time. Ventilation is thought by many to be perfectly pro- vided for if there be a ventilator placed at the top of the room, presenting one small opening for the egress of the bad air. To show the fallacy of this, we need only perform the experiment represented in 240 ELEMENTARY CHEMISTKY. the adjoining cut. The bottle is fitted with a tin cover, through which a tube is inserted. The jar represents a room sealed tightly on all sides against the incoming of the air, and with only one opening for ventilation. Place a lighted candle at the bot- tom, and it will soon be extinguished, no O seeming to come in to feed the flame. Place now in the tube a slide, composed of two slips of tin soldered at right angles to each other, thus dividing the tube into four longitudinal portions. The lighted candle will burn freely, and a bit of smoking paper held at the top of the tube will reveal a current passing downward through two of the openings, and a cur- rent passing outward through the opposite ones. This shows very clearly the effect of a division in the opening used for ventilation. Of course, no room can be made as nearly air-tight as the bottle, since some air will come in at the sides, around the win- APPENDIX. 241 dows, etc. ; still, this experiment illustrates the im- perfection of the ordinary ventilator. The necessity of some means of changing the air is shown by the fact, that two persons sleeping in a room 15 ft. square will vitiate the atmosphere in three hours, and so rebreathe it twice before morning, and then wonder why they wake up with a head- ache. (Page 73.) CYANOGEN. The pupil will here distinguish ferrocyanide of potassium from the ferricyanide. The latter is the red prus- siate of potash. When the yellow prussiate is added to a salt of the sesquioxyd of iron, prussian blue is formed. This is employed in water-colors and oil-paintings, and when dissolved in oxalic acid, constitutes blue ink. (Page 83.) THE LAW OF DIFFUSION may be finely illustrated by the experiment shown in the cut. The upper jar is to be filled with H, and the lower one with CO 2 . The result will be that described in the text. fPageSG.) CHLO- RINE. In the arts, and for many ex- periments, Cl is made by simply a 1'neumatic trough, d Bell glass receiver. b Retort. e Shelf in pneumatic trough. c Lamp-stand. / Spirit-lamp. 11 242 ELEMENTARY CHEMISTRY. heating, in a glass retort, black oxyd of manganese, with muriatic acid. The reaction is this : MnO 2 + 2HC1 = MnCl + 2HO + Cl. Indeed, most of the experiments in Cl may be per- formed by taking a deep glass jar, and placing at the bottom some chloride of lime. By pouring upon this a little dilute SO 3 , the Cl will soon fill the jar and dis- place the air. Phosphorus will in- flame spontaneously in CL The gas is very annoying, and the room must be thoroughly ventilated. In preparing Cl, as mentioned in the text, take four parts of common salt and mix it thoroughly with three parts of black oxyd of manganese; Phosphorus in ci. put this mixture in the retort, and pour upon it dilute SO 3 . The gas will be evolved abundantly. The reaction is as follows : MnO 2 + NaCl + 2SO 3 . HO = MnO . SO 3 + NaO . SO 3 . HO+C1. The gas should be collected over warm water, as it is largely absorbed by cold water. By passing the gas for some time through a bottle of HO, a solution will be formed which will perform all the experiments in bleaching very nicely. To illustrate this, pour some of the chlorine-water into a test-tube of HO blackened with a few drops of ink. (Page 88.) BLEACHING POWDER is considered to be a mixture of the chloride of calcium and the APPENDIX. 243 hypochlorite* of lime thus, CaCl + CaO . CIO. It is produced in great quantities in the process of making sal-soda. (Page 93.) BIBORATE OF SODA (NaO.2BO 3 +10HO) is used in soldering and in brazing, and also in "blow-pipe analysis." When borax is*' melted with oxyd of chromium, it gives an emerald green ; with oxyd of cobalt, a deep blue ; with oxyd of copper, a pale green ; with oxyd of manganese, a violet. (Page 103. ) PHOSPHIDE OF HYDROGEN is frequently made by nearly filling a retort with a strong solution a Retort filled with solution of potash, with pieces of phosphorus in it. b Rings of vapor, from the combustion of the phosphuretted hydrogen. of KO, and then adding a few drops of ether and some small bits of phosphorus. The object of the ether is to prevent the explosion of the first bubbles of gas, as they come off, in the retort. The beak of the retort should dip under HO before applying the heat. The following singular story is told of the prob- able discovery of phosphorus many years before that of Brandt, the reputed discoverer. A certain prince San Severe, at Naples, exposed some human 244 ELEMENTAEY CHEMISTRY. skulls to the action of several reagents, and then to the heat of a furnace. From the product he obtained a vapor which kindled at the approach of a light, and continued to burn aglow for months without ap- parently diminishing in weight. San Severo refused to divulge tJfe process, as he wished his family vault to be the only one to possess a "perpetual lamp" the secret of which he considered himself to have discovered. (Page 110.) SAL-SODA is sometimes called " salts of tartar," and when purified is commonly sold under that name. It is used by barbers for cleaning the head, and is a prominent constituent in many hair- washes ; 20 or 30 gr. in a gill of warm HO makes an excellent solution for such a purpose. (Page 115.) METALS OF THE ALKALINE EARTHS. These are termed alkaline because they are caustic, and earths, because they are insoluble in HO. The annexed cut shows an im- proved form of lime-kiln, in which the process is continuous. At a, Z>, c, d, are the doors for fuel, ash-pit, etc. The lime- stone is fed at the top from time to time, while the lime is taken out at / as fast as formed. Concrete is a cement of coarse gravel and water- Lime-Kiln. APPENDIX. 245 lime. It is of great durability. Whitewash is a mere " milk of lime." " Hard finish" is a kind of plaster in which gypsum is used to make the wall smooth and hard. " Ccdcimining" is a process of whitening walls with a wash of plaster of paris, or whiting. (Page 119.) PHOSPHATE OF LIME. When bones are burned, a tribasic phosphate of lime is formed thus, 3CaO.PO 5 . When this is heated with SO 3 , the change is as foUows : 3CaO . PO 5 + 2(SO 3 . HO) = CaO.PO 5 .2HO + 2(CaO.SO 3 ). This mixture is sometimes called the superphosphate of lime, al- though the term belongs properly only to the CaO . PO 3 . By filtering, the CaO.SO 3 is removed, and the superphosphate is sold as a fertilizer, or may be heated with charcoal to form P thus : 2(PO 5 .3HO) + 16C = 2P + 6H + 16CO. (Page 129.) When iron is cast in large masses, the metal has time to crystallize, and this weakens it very much. When immense cannon are cast, like the Fort Pitt gun, a stream of water is allowed to run through it to hasten the cooling process. When the melted iron is cooled in an iron mould, this chills the surface instantly, and makes it extremely hard. The product is called " chilled iron" and is used for safes and other burglar-proof instruments. (Page 133.) COPPER.- Both lead and copper are fre- quently found native, the former in Missouri and Nor- thern New York ; the latter near Lake Superior. In such cases, the extraction of the metal from the spar in which it is imbedded is very simple. The ore is 246 ELEMENTARY CHEMISTRY. ground to powder in a stamp-mill, and then, 'by re- peated washing, during which the metal sinks by its superior specific gravity, is separated from the spar, and is prepared for the furnace, where it is melted and cast into bars for the market. The ore, contain- ing oxyd, or carbonate of copper, can readily be re- duced by heating with charcoal and lime, as in the process of iron-smelting. The sulphurets, however, are reduced with much greater difficulty. They con- tain much iron pyrites, which must be removed. They are first roasted, to convert a part of the sul- phurets of copper and iron into oxyds. They are then smelted, as we have described before, and the iron mostly passes off in the slag, while the copper is reconverted into a sulplmret. This is next roasted, and lastly heated to so high a temperature, that the sulphur leaves the copper as SO 2 , while the melted metal is drawn off, ready for the market. (Page 138.) COBALT is a reddish-white metal, found in combination with arsenic. It received the name cobalus from the miners, because its ore looked so bright that they thought they would obtain some- thing valuable, but by roasting, it crumbled to ashes. They therefore thought they were mocked by the Kobolds the evil spirits of the mines. The oxyd of cobalt makes a beautiful blue glass, which, when ground fine, is called smalt . It is used for tinting paper, and by laundry women to give the finished look to cambrics, linen, etc. Its impure oxyd, called zoffer, imparts the blue color to common earthenware and APPENDIX. 247 porcelain. The chloride (CoCl) is used as a sympa- thetic ink. Letters written with a dilute solution of it are invisible when moist with the HO absorbed from the air, but on being dried at the stove, again become blue. If the paper be laid aside the writing disappears, but may be revived in the same manner. A winter landscape may be drawn with india-ink, the leaves being added with this ink. On being brought to the fire it will bloom into the foliage of summer. MANGANESE is a hard, brittle metal, resembling cast-iron in its color and texture. It takes a beau- tiful polish. Its binoxyd, the black oxyd of man- ganese, has been spoken of as used in the manufac- ture of O, Cl, etc. By fusing four parts of MnO 2 and three and a half parts of chlorate of potash with five parts of KO dissolved in a little water, a dark green mass is obtained called " chameleon mineral" If a piece of this be dropped into HO, the solution will undergo a beautiful change from green, through various shades, to purple. This is owing to the gradual formation of permanganic acid. The change may be produced instantaneously by a drop of SO 3 . NICKEL is a grayish metal. Like cobalt, it is a constituent of meteorites. It is mined in Pennsylva- nia, in large quantities, by the United States Govern- ment, for making nickel cents. Its principal use is in the alloy called German silver. The salts of nickel possess a beautiful green tint. The rare gem chryso- prase is colored with oxyd of nickel. BISMUTH is a reddish-white metal. It is known 248 ELEMENTARY CHEMISTRY. chiefly as an oxyd, in which form it is much prized as a cosmetic by those whose fading charms necessi- tate the use of pearl-powder. This should not be indulged in by ladies intending to visit chemical la- boratories, or lectures, as a few bubbles of HS es- caping into the air will change the snow-white com- plexion into a most suggestive black. ANTIMONY was discovered by Basil Valentine, a monk of Germany, in the fifteenth century. It is said, that to test its properties, he first fed it to some hogs kept at the convent, and found that they thrived upon it. He then tried it upon his fellow- monks, but perceiving that they died in consequence, he forthwith named the new metal, in honor of this fact, anti-moine (anti-monk), whence our term anti- mony is derived. Antimony is found as SbO 3 . It is a brittle bluish- white metal, with a beautiful laminated crystalline structure. It is used simply as an alloy for type- metal, Britannia-ware, etc. Its test is HS, which throws down a brilliant orange-colored precipitate. Example : Melt a small fragment before the blow- pipe, and throw the melted globule upon an inclined plane. It will instantly dart off in minute spheres, each leaving behind a long trail of smoke. (Page 149.) NITRATE OF SILVER is much used in photography. An account of the processes pur- sued in this art may be interesting to some. The daguerreotype is named from M. Daguerre, the dis- APPENDIX. 249 coverer, who received a pension of 6,000 francs per year from the French government. A plate of cop- per, plated on one side with silver, is exposed to the vapor of iodine until a compound of iodide of silver is formed upon the surface. This is extremely sen- sitive to the light, and for this reason the process is always conducted in a dark closet. The plate is then quickly carried, carefully covered, to the camera, and placed in the focus, where the rays of light from the person whose " picture is being taken" fall directly upon it. These rays decompose the iodide of silver, setting free the iodine. The amount of this change is directly proportional to the num- ber of rays that are reflected from different parts of the person to form the image in the camera. A white garment reflects all the light that falls upon it, so that part of the plate corresponding will be very much changed. A black garment reflects no light, so that part will not be changed at all. The different colors and shades reflect varying propor- tions of light, and so influence the plate correspond- ingly. When the plate is taken out of the camera, it is carefully covered again and carried quickly into the dark closet. No change can be detected by the eye ; but now expose it to the vapor of mercury, and wherever the silver has been freed from the iodine, the Hg combines with it, forming a whitish amal- gam. The picture thus evoked comes forth nearly perfect in its lights and shades, but the whole side 250 ELEMENTARY CHEMISTRY. of the plate is covered with the iodide of silver, which would blacken if we should carry it out into the light. This must, therefore, be removed, so we wash the plate with hyposulphite of soda (NaO.SO 2 ). This dissolves the iodide of silver, except where it has been fixed by the mercury, and our picture needs only washing and a little paint on the lips and cheeks to be finished. If, instead of iodine, we had used bromine, the bromide of silver thus formed would have been much more sensitive to the light, and the picture could have been taken much quicker. PHOTOGRAPHY (light-drawing) is founded essentially upon the same principles as daguerreotyping. The process varies so much with different operators that only the general outlines can be given. The details depend upon the quickness, exactness, and skill of the artist so much, that the same materials in differ- ent galleries produce vastly different photographs. So much skill has been attained in this art, that instan- taneous views are now taken by Anthony & Co., of New York. In their gallery the camera tube is closed by a slide which is drawn to its place by a heavy weight. The camera is "focused," for instance, upon a regiment of soldiers moving up Broadway, and the tube opens just as they are raising their feet for a step : before they place them on the ground the slide falls and the picture is taken they are photographed all standing on one foot, and with the other in the air. The process is as follows : The glass plate is (1) thoroughly cleansed ; (2) a small APPENDIX. 251 quantity of iodized collodion* is poured upon it, which covers the glass with a thin transparent film, when (3) it is put in the " nitrate of silver bath," t where the salt of silver in the bath is absorbed by the collodion film and changed to iodide of silver. The plate is now ready for the picture. After the sitting the plate is (4) taken, carefully protected from the light, to the operator's room. Here the picture is (5) developed by a solution of protosulphate of iron, with a little acetic acid added. (6) It is washed thoroughly ; (7) it is fixed with a solution of hyposulphite of soda ; (8) it is washed and dried, and (9) coated with amber varnish to preserve the film from accidental injury. This completes the " negative." From this the pictures are (1) "printed" by placing the negative upon a sheet of prepared paper,! and exposing it to the sun's rays. The lights and shades are now reversed, and when the colors are sufficiently deepened the picture is (2) washed, (3) toned in the " toning-bath," which contains chloride of gold, and imparts the delicate color to the photograph, (4) ivasfod, (5) fixed, by * Iodized collodion is composed of gun-cotton dissolved in alcohol and ether, iodized with iodide of ammonium and bromide of cadmium. f The nitrate of silver bath contains nitrate of silver, iodide of silver, and water. \ The paper is " sensitized" by immersing it in a solution of clilcride of sodium, and then in one of nitrate of silver, thus fill- ing the pores of the paper with the chloride of silver, which is extremely sensitive to light. - . , . . f : 252 ELEMENTARY CHEMISTRY. placing the paper in hyposulphite of soda, (6) washed, (7) dried, and (8) mounted on card-board, which completes the picture. ORGANIC CHEMISTRY. All organic substances contain carbon, and there- fore they have been defined as the " carbon com- pounds." The phenomena of Allotropism and Isomer- ism are evidence that the grouping of a compound has much to do with its peculiar properties. The recent advances of the science have developed sev- eral features worthy the attention of the student. A RADICAL is the base of a system of compounds. Example : Na forms, by union with O, the oxyd of sodium. This combines with HO, forming the hydra- ted oxyd of sodium, and this again with various acids. In this way a regular series of compounds are produced, in which Na is the starting point the root, as it were. Thus : Na Sodium. NaO Oxyd of sodium. NaO.HO Hydrated oxyd of sodium. NaO.HO.SOs Sulphate of the hydrated oxyd of sodium. NaO.HO.NOs Nitrate of the hydrated oxyd of sodium. A COMPOUND RADICAL is a compound that re- sembles an element in all its chemical behavior, and can be oxydized and transferred from one compound to another, forming chlorides, salts, etc., in the same manner as a metal, like copper or iron. Example : In the destructive distillation of C 4 H 3 O 2 .(alcohol) APPENDIX. 253 and SO 3 , the acid takes out an atom of HO, leaving C 4 H 5 O common sulphuric ether. Now, by taking an atom of O from this, there remains a colorless gas, C 4 H 5 , which has received the name Ethyl and the symbol Ae. This plays the part of an element, and being composed of two elements, is called a compound radical. It is the root of a series of compounds, thus : Ae-Ethyl (the radical) C 4 H 6 . AeO Oxyd of ethyl (ether) C 4 H 6 O. AeO.HO Hydrated oxyd of ethyl (alcohol) C 4 H 6 O.HO. AeCl-Hydrochloric ether C 4 H 6 C1. AeCy Cyanide of ethyl C 4 H 6 Cy. AeNO 5 Nitrate of the oxyd of ethyl (nitric ether).... C 4 H 6 O.NO. By this we see that ether is the oxyd of ethyl, and may be represented by the symbol AeO, while alco- hol is the hydrated oxyd of ethyl, and may be repre- sented by the corresponding symbol AeO . HO. HOMOLOGOUS bodies are those which differ from each other by the constant addition of C 2 H 2 , or its multiple. By the decomposition of common alcohol, we procure a series of alcohols, ethers, and acids, which differ from each other by constantly adding C 2 H to the preceding member of the group. Alcohols. Acids. Ethers. Methylic.. ..C 2 H 4 O a Formic .C 2 H 2 4 Methylic. ...C 2 H 3 Common . . ..C 4 H 6 O a Acetic .C 4 H 4 4 Common ...C 4 H 5 Propylic . . . C 8 H 8 O a Propionic .. C 6 H 6 4 C a H 7 Butylic.... -.C 8 H 10 O a Butylic .C 8 H 8 4 Butylic . ...C 8 H,0 Amylic.... ..C 10 H 12 O a Voleric -C 10 H ]0 4 Amylic . ...C 10 H n O C 12 H 14 O a Caproic .C 12 H 12 4 C 12 H 13 C 14 H 16 O a >AHY LOAN J'K 24^ M ftrtmt^ UNIV F * 5 * WI " ii BKrltv VB 16913