The chemist. Volume 1, 1824
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m> t ©ijtmtst << - Search, undismayed, the dark profound Where Nature works in secret; trace the forms Of atoms, moving with incessant change Their elemental round; behold the seeds Of being, and the energy of life, Kindling the mass with ever-active dame ; — Then say if nought in these external scenes Can move thy wonder?- — ” No. XXVI.] SATURDAY, SEPTEMBER 4, 1824. [Price 3d. J.  the comparative Value of Oil and Coal Gas . . ih. denied . . . 412 Dictionary of Chemistry . 415 To form Water . . 408 Potatoes a Substitute for Soap .... 416 LANA’S BALLOON. balloons. If you think it worth To the Editor of the Chemist. inserting in your miscellany, with Mr. Editor, — In looking over the illustrative drawing, it is at some old books a few days ago, your service. I found the following little account Yours, obediently, of a very early attempt to construct Black Letter. 20 402 THE CHEMIST. “ Lana was an Italian Jesuit, living, we believe, m the north of Italy, and in 1670 published a book at Brescia, under the title Prodromo dell Arte Maestra , in which he describes, or rather dreams of a boat, having a ball of copper, twenty fdet in diameter, the substance of which was to be l-08th of a line thick, fixed at to each corner. His boat was have a mast and sail, but how she was to be raised does not ap¬ pear, for his scheme of exhausting the air of the balls would not an¬ swer the purpose. Gallien, who published, in 1755, L’Art de Navi- ger dans les Airs , seems to have dreamt more scientifically than Lana, for he proposed to construct a machine of linen, covered with wax and tar, the belly of which was to be filled with air lighter than the atmosphere. From such imperfect beginnings did the pre¬ sent science and art of aerostation arise/' CHEMISTRY AS A SCIENCE. Art. XXIV. It is an old maxim of an old system of philosophy, that bodies cannot act where they are not. So far was this maxim once carried, that it was supposed absolute con¬ tact was necessary for one sub¬ stance to have any effect on ano¬ ther. The error of this maxim, thus generally expressed, is ob¬ vious from magnetic attraction, and from gravity, by virtue of which, among numerous other ef¬ fects, the far distant moon causes the Hood and ebb of the tides of our ocean. This error is further obvious, from the well-known ex¬ periment of Sir Isaac Newrton, who found that it required a very con¬ siderable fame to bring two pieces of glass within a certain distance of each other, and that no force he could apply would bring them in contact, for before they absolutely touched each other, they were shi¬ vered to pieces. Thus we should rather be inclined to suppose that the reverse of this maxim is cor¬ rect, and that we ought to say all bodies possess a mutual power of alfecting each other at a distance, or their inlluence extends where they are not. It is probable, how¬ ever, that this old maxim has still a very considerable inlluence ; and even those philosophers who deny it when thus stated, seem to adopt it as the principle of their logic. Thus, in the first example wre quoted, the magnetic influence operating at a distance lias been explained by the intervention of a fluid, and there have been nume¬ rous attempts to account for the laws of gravity, by referring it to some clastic ether. We believe the same error has had consider¬ able influence on most of the theo¬ ries of light. There being a diffi¬ culty in explaining how men see, it was supposed that a subtle fluid was dispersed from every point of luminous bodies, bearing with it their form and features, and en¬ tering the eye, imprinted their re¬ presentation on the retina, caus¬ ing in us sensations of sight. — Admitting all this, though there are some facts which cannot be explained by this theory, such as seeing objects single with both our eyes, and the image being inverted on the retina, while the sensation is the right side upwards, if we may so express it; still, as the image goes no further than the re¬ tina, and there is no vision without the optic nerve and the brain, it must be supposed that the action of light proceeds to the latter, and there is as great a difficulty to get over at the end of the supposition as before it was made. Conceiving, therefore, that nothing is gained by supposing vision to be produced by a substance entering the eye, or by the undulations of a fluid, the theoiy of some philosophers, we shall, under this division of the subject, merely state such facts con- cerningriglit as' have any connexion with chemistry, without at all en- tering into any discussions as to what causes sensations of sight, and whether it is a distinct sub¬ stance, or whether there is some generally diffused ether, the vibra¬ tions of which produce vision, THE CHEMIST. 403 while some other motions of itpro- du ee gravity, electricity, and all other phenomena. No definition can, in our view cf the matter, be given of light; what the term stands for in ordinary language is known to every man; and the wisest philosopher may confuse the reader by explana¬ tions, but cannot make him more sensible of what light is, than by referring him to his own know¬ ledge. Every person not blind knows what is meant by the light of the sun, the light of a candle, or of any other burning body. Within any distance that we are capable of measuring on the earth, there is no perceptible interval be¬ tween the moment of illuminating an object and that object being perceived. Thus in the experi¬ ments frequently made on the ve¬ locity of sound, it is assumed that the perception of the flash of a gun is visible at the same moment to a man at a distance of ten miles as to him who fires the piece. From some astronomical observations, however, it has been concluded that an interval elapses between the rising of the sun and the per¬ ception of that rising on the earth. Roemer, a Danish philosopher, was the first person who calculated, by some observations on the satellites of Jupiter, that light traverses a distance equal to one half of the earth's orbit in about eight mi¬ nutes, or that it moves at the rate of 200,000 miles in a second. His calculations have been strengthen¬ ed by observations on what is called the aberration of the light of the fixed stars, and it is now a generally received opinion that light travels with this velocity, or requires a certain time to move through a certain space. As, how¬ ever, time is itself measured by the motions of the heavenly bodies, it is possible that what is called the aberration of light, or its velo¬ city, is produced by some un¬ calculated motion of the planetary system. We give no opinion on so abstruse and conjectural a point of philosophy, but merely hint at the fact of time itself being measured by the motions of the planetary system as possibly serving to ex¬ plain the astronomical phenomena mentioned, without assuming that light is a substance projected from certain bodies with indefinite de¬ grees of velocity. In most systems, however, light is described not only as the cause of vision, but as moving with almost measureless rapidity, and as being endowed with a power of repulsion among its own particles. A great number of appearances are explained by the refraction of light. Every body knows that when an oar or stick is partly plunged into water, it does not appear straight, as when wholly out of the water, but broken. This effect, as well as several others, is said to be caused by the refraction of light. The general fact is, that when transparent mediums of dif¬ ferent density intervene between the seen body and the eye, that body is not seen in its proper place. As far as the sun is concerned, this effect is only observed when its rays pass obliquely from one me¬ dium to another of different den¬ sity ; and when they pass, into a denser medium, they are refracted towards, and into a rarer, from the perpendicular. The variation of the rays from the rectilineal path is always proportional to the obliquity with which they strike the re¬ fracting surface, so that the sine of the angle of refraction is always in the same propor¬ tion to the angle of incidence. In general the degree of refraction is proportional also to the density of the medium; hut combustible or inflammable bodies are observed to occasion a greater deviation than others in proportion to their density. A knowledge of this fact led the illustrious Newton to con¬ jecture, long before the diamond was burned and water decomposed, that they both contained a com¬ bustible material. The law that the degree of refraction is in pro¬ portion to the density of bodies, though long very generally accre¬ dited, has lately been shown, by Messrs. Arago and Petit, not to hold in all cases. When liquid 2 D 2 404 TI1E CHEMIST. bodies are converted into gases, their retractive power diminishes in a greater proportion than their density. Thus the refractive power of sulphuretof carbon, while liquid, as compared to that of air, is more than 3, while its refractive power, when in a state of vapour, is only 2. Advantage has been taken of the refractive power of different substances to judge of their purity. Dr. Wollaston lias invented an in¬ strument for measuring the refrac¬ tion of different substances, which has an index, so that the degrees are read off at once. It is, for ex¬ ample, stated, that the refractive power of genuine oil of cloves is 1.585, while it is found in com¬ merce only 1.498, in consequence of its having been adulterated with some less refractive oil. In consequence too of the refractive pow er of different substances be¬ ing a constant quantity, and in some measure an indication of their purity, tables are in general given, in chemical books, of the degree in which it is possessed by different substances. We do not think it necessary to give these tables, but shall content ourselves with ob¬ serving, that no substance is equal to hydrogen in refractive power ; it surpasses all other gases, and indeed all other known bodies. This principle exists in great abun¬ dance in oils, resins, and gums, united to charcoal and oxygen ; and it seems to be supposed, with good reason, that the refractive power of the element exists still in the compound. The chemical pro¬ perties of hydrogen, as well as of most other elementary bodies, are so modified by a union with other substances, that very often in the compound no trace can be found of the properties of either. But it seems different as to light ; and the refractive power of two elements when combined seems equal to their refractive power when by themselves. Carburet of sulphur exceeds all fluid bodies in refrac¬ tive powers, surpassing even flint glass, topaz, aud tourmaline. Of solids, the diamond, realgar, and chromate of lead possess the great¬ est refracting powers. The phenomena of the prism, and probably of colours in general, seem to be occasioned by the re¬ fractive powers of different sub¬ stances. If a ray of light, admitted through a small hole of a window- shutter into a darkened room, be made to pass through a triangular prism and received on a sheet of white paper, the image or spectrum is found to be oblong, terminated with semicircular arches, and to consist of several colours. They are the following, and are arranged in the following order : red, orange, yellow, green, blue, indigo, and violet. If the whole spectrum be divided into 860 parts, the red, it was ascertained by New'ton, would occupy 45, the orange 27, the yel¬ low 48, the green 60, the blue 60, the indigo 40, and the violet 80. This effect is supposed to be a proof that light consists of seven distinct rays, each of which is more or less refracted than every other by the prism. As a further proof of this, it is observed, that if the rays separated by a prism be con¬ centred on one spot by a lens, they will reproduce colourless light. This property of the different rays, to be more or less refracted, is called their refrangibility ; and the red rays are least refrangible, the violet the most. The separation of a ray or beam of light into these different coloured rays, is undoubt¬ edly a curious fact, more especially as each one of them has different characteristics and powers. Thus, according to Dr. HerschelPs ex¬ periments, the illuminating powrer of the light green ray in the centre is greater than that of any other ray, and much greater than the illu¬ minating power of the rays at either end of the spectrum. Thus, also, according to the experiments of the same philosopher, confirmed by the experiments of Sir IT. Ehgel- field and M. Berard, each of the rays possesses a different healing power, the violet ray heating the least, and the red the most; while there was an unilluminated point beyond the spectrum, where the heating effect was almost equal to that of the red ray. Thus also THE CHEMIST, 405 light has the property of deoxi¬ dizing substances, and it is found that the red ray deoxidizes least, and the violet most; and that even beyond the violet the deoxidizing effect is perceptible where there is no visible light. We are indebted for a knowledge of this effect to Hr. Wollaston, and his observa¬ tions have been confirmed by M. Berard. He exposed different sub¬ stances to each ray, and found that the chemical intensity, for this is a chemical phenomenon, was great¬ est at the violet end of the spec¬ trum, and extended a little beyond it. Light, therefore, which appears on first inspection to be so simple, is found, when examined according to this theory, to consist of seven distinct substances, each of which possesses some properties to dis¬ tinguish it from every other. In¬ dependent, then, of light producing vision, it produces heat, and it de¬ oxidizes bodies. The other pro¬ perties attributed to light, we shall describe in another Paper. CHEMICAL SOCIETY. We understand, from a copy of the regulations of this Society hav¬ ing been obligingly forwarded to us, that it was finally constituted on August 12th, and a set of rules agreed to. The Society is to con¬ sist of both ordinary and honorary members ; to be governed by a president, a council, and other officers, who are to be annually elecied ; is to meet once a fort¬ night, and to have an nnnual meet¬ ing. The subscription, we observe, is to be, “ at the entrance of each ordinary member, one guinea, and also the further sum of one guinea half yearly, to commence the se¬ cond quarter day from the date of his entrance.” “ The object of the Society is the study of chemistry in all its branches,” “ The lec¬ ture-room and library of the So¬ ciety are to be open from nine in the morning until ten in the even¬ ing, except Saturdays, when it is closed at three o’clock.” “ The ordinary meetings of the Society are to be occupied by the delivery of lectures in various branches of chemistry, by the reading of me¬ moirs, by the performance of ex¬ periments, or by the discussion of any subjects connected with che¬ mistry, as the council may direct and approve of.” Visitors are to be admitted to the meetings, but must receive permission from the president to speak on any of the subjects discussed by the Society. We have not learned what num¬ ber of members have joined the Society ; but its object is so laud¬ able, that we have no doubt it will be both numerous and respectable. We repeat our wishes for its wel¬ fare, and our offer to promote its objects by any means in our power. ON THE COMPARATIVE VA¬ LUE OF OIL AND COAL GAS. , ( Abridged from the Edinburgh Philo - sophical Journal.) The author of this Paper, Dr. Fyfe, who is Lecturer on Chemis¬ try at the School of Arts in Edin¬ burgh, begins by stating, although much apprehension was excited on the first introduction of gas lighting, by the necessary large collections of an explosive gas, that only one gas holder has been blown up since the practice was generally introduced ; and this took place at Manchester in the infancy of the art, and was occasioned by a work¬ man applying a lighted candle to the part whence gas was issuing and mixing with atmospheric air. A few accidents have occurred by the gas escaping from the pipes, but these have also in general been owing to carelessness. Shops and apartments are not close enough to keep the gas confined ; and even if they were, the quantity which can escape is too trifling, compared to the quantity of air in the apart¬ ment, to occasion any mischief. Coal gas is most explosive when mixed with about five parts of air. It would he therefore requisite, in a room which contains 1728 cubic feet, lighted by a stream of gas, consumed at the rate of five cubic feet in an hour, that the burner should be left open upwards of fifty hours before the mixture be- 400 THE CHEMIST.' comes explosive. When coal gas is used, its offensive odour gives warning of its escape ; so that one of its most noxious qualities is a valuable safeguard. The ingredients found in oil and in coal gas, when sent into the pipes for burning, and after both gases have been purified, are or ought to be the same, but they exist in somewhat different pro¬ portions. The following tables, the first by Hr. Henry, the second by Dr. Fyfe, show these different ingredients and their proportions. The gas is first subjected to the action of chlorine, which condenses a certain portion, supposed to be partly olefiant gas and partly a volatile oil. Coal Gas. The following table is the result of experiments, made on five kinds of coal gas, prepared from Wigan Canal Coal. The three first were collected from an opening in the pipe between the retort and the tar pit, half an hour after the commencement of distillation; No. 4 was taken five hours, and No. 5 ten hours after the beginning. rI he carbonic acid and sulphuretted hydrogen were removed by washing the gas with a solution of potassae. After being condensed by chlorine, 100 parts contained Gas. Specific Gravity. Condensed by . , , Cliirorine. Azote’ Carburetted Hydrogen. Carbonic Oxide. Hydrogen No. 1 650 13 per cent. 1.5 94.6 4 0 2 620 12 6 82 2 10 3 630 12 2 66 14 18 4 600 7 5 60 12 26 5 345 0 10 20 10 60 Oil Gas. The gas, Nos. 1,2, 3, w as procured from whale oil, previously boiled, to free it from water, the heat of the retort being reduced at each suc¬ ceeding experiment, till it was just sufficient to decompose the oil. After being condensed by chlorine, 100 parts contained Gas. No. 1 2 3 4 Specific Gravity. Lost by . „. Chlorine Azote. Carburetted Hydrogen. Carbonic Oxide. Hydrogen. 464 6 per cent. 7 30 15 48 590 19 5 40 15 40 758 22.5 6 65 20 10 906 38 5 76 15 5 The readerwillseethat,in thebest specimen of oil gas, the carbonic oxide is in greater proportions than in the best specimens of coal gas, and in the latter the carbu retted hydrogen is most abundant. The hydrogen in both appears to in¬ crease, as the temperature at which they are formed becomes higher, and is always greatest in the last portions. The quantity of gas obtained from coal and from oil, varies according to the nature of the ma¬ terial and the manner of treating it. The author quotes from various writers the following statement of the quantity of gas obtained from two hundred species of coals: — WalJsend, about 750 cubic feet Parrot . . . 860 Lesmahago . . 1080 Newcastle . . 1080 Wigan Orral . 700 Cannel (doubtful) 1200 From which 1000 feet are taken as the average of the quantity of gas which ought to be obtained from good coal. The quantity of gas obtained from oil varies from 97 to 120 feet, whence it is stated, that 100 feet may be considered as a fair estimate of the quantity of gas usually obtained from a gallon of oil. Dr. Fyfe says, that if the oil be allowed to flow into a retort brought just to a red heat. THE CHEMIST. 407 there is comparatively little gas, but a great deal of volatile oil. When the retort is made intensely hot, lamp black is formed in con¬ siderable quantities. In both these modes then the oil may be wasted to a considerable extent ; and it seems to be decomposed most advantageously when the re¬ tort is brought to a full red heat. The illuminating power of oil and coal gas has been differently stated by different persons. Ac¬ cording to some, the power of the oil gas is as three and a half, the coal gas being one, while, according to others, it is only two, and even not greater. On this question, however, turns one which is of very great importance, whether oil or coal gas works are most advan¬ tageous ; and we must, therefore, follow Dr.Fyfe more closely in this part of his work. He first throws doubts on some experiments of Mr. Ricardo's, and of other gen¬ tlemen, on account of their having been incorrectly made, while he seems disposed to admit the accu¬ racy of the experiments of Messrs. Herapatli and Rootsey, which do not give so high an illuminating power to oil gas. Mr. Dewey’s expe¬ riments published in the Annals of Philosophy, last December, and which showed a great degree of illuminating power in oil gas, were made, it appears, as well as some other experiments, with coal gas of a very small specific gravity, only 406 ; and Dr. Fyfe contends, that the illuminating power of both gases, after being properly purified, is in proportion to their specific gra¬ vity. The oil gas Mr. Dewey used was 939, which is very good ; and if (says Dr. Fyfe) a good oil gas is only three and a half times superior to a very inferior coal gas, its supe¬ riority must be much reduced when brought into competition with the latter, when of an equally good qua¬ lity. DrHenry proposed to ascertain the illuminating power of each gas by the quantity of oxygen neces¬ sary for its combustion, and, tried by this test, he obtained the fol¬ lowing results » One hundred volumes of coal gas, of the Specific Gravity 345 500 620 630 650 Took of Oxygen, 78 166 194 196 274 One hundred volumes of oil gas., of the Specific Gravity, Took of Oxygen,” 464 116 590 178 758 220 906 260 From this it appears, that the best oil gas is to the worst coal gas as three and a half to one, while the best of both stand in the relation to another of 26 to 21. On the theory, that the olefiant gas con¬ tained in both is the principal source of light, as this may be con¬ densed by chlorine, Dr. Fyfe pro¬ poses this as a test of the illuminat¬ ing power of each. The mixture mast be excluded from light to prevent any action on the carbu- retted hydrogen. Dr.Fyfe recom¬ mends the following method for trying this experiment : — A gradu¬ ated jar, inverted in a water trough, must be filled to 50 with the gas ; 50 measures of chlorine must then be introduced, the tube being co¬ vered with a paper shade, to pre¬ vent any action on the other gases. In the course of from 10 to 15 mi¬ nutes the condensation is complete ; and as chlorine and olefiant gases combine in equal proportions, the diminution in the mixture indicates correctly the quantity of olefiant gas in the gas subjected to trial. This, Dr. Fyfe says, promises to be an accurate modeofascertaining the comparative illuminating pow¬ ers ; and by this method he has found the oil gas prepared in Edin¬ burgh to be to the coal gas as 31 to 17, or nearly 1.8 to 1. Dr. Fyfe, we see, admits that the other con¬ stituents of both gases possess some illuminating powers; and unless the proportion of these other in¬ gredients were the same in both, we cannot see how his method can be any thing more than an approxi- 408 THE CHEMIST. ination to accuracy. He concludes this part of the subject, however, by stating, “ I suspect coal gas will be found to possess, or at least may be made in general to possess, about half the illuminating power of that from oil.” He has found this to be the ca^e with those made in Edinburgh, by producing the same quantity of light and marking the quantity of gas consumed. He then enters into some calcu¬ lations to show the cost of manu¬ facturing oil and coal gas ; but this depends on so many circumstances, that we cannot follow him. Having stated his opinion as to the quantity of light to be obtained from the two g-ases, we must leave it to the discre¬ tion of our readers to choose either, as they are so placed as to obtain the material at a dear or cheap rate. But though Dr. Fyfe thinks that, at present, oil gas cannot be made so advantageously as coal gas, lie does not assert that it never can. “ Oil gas establishments,” he says, “ are in their infancy ; and as, by the present, mode of de¬ composing oil, there is a consider¬ able loss of illuminating power, other and more effectual methods of decomposing it may be disco¬ vered, which will allow it to be offered at a cheaper rate, and thus bring it into competition with coal gas, provided we consider it as having three times the illuminating power; but if, as I have endea¬ voured to show, it is only about twice that of coal gas, I fear it never can come into competition with it.” We observe that the Coal Gas Company of Edinburgh have lately employed Professor Leslie to make some experiments on the compara¬ tive illuminating powers of oil and coal gases, and they have pub¬ lished the results of his experi¬ ments, which nearly coincide with those of Dr. Fyfe. The Professor's experiments are, however, not yet finished; and when they are pub¬ lished we shall lay them at length before our readers. A TO FORM WATER. To the Editor of the Chemist. Mr. Editor, — You have lately shown your young readers how to decompose water ; and I w ill, with your permission, point out to them how they may compose it of its two constituent principles. Let them supply themselves with a glass bottle, as seen in the little drawing I send herewith. It is to be provided with a cork, through which a small hole is pierced, and in this a glass tube is inserted. They must put into the bottle a small quantity of iron filings, and pour on this about twice as much sulphuric acid, by weight, pre¬ viously diluted by about four times as great a quantity of water. After these substances are placed in the bottle, put in the cork and set fire to the gas, which is hydrogen, that will issue from the mouth of the tube. When this is done, invert over the flame a glass jar, as seen in the little drawing ; and in a very short time its inside will be covered with a very fine dew, which is pure water, arising from the combustion of the hydrogen gas, produced from the materials in the bottle, and the oxygen gas of the atmosphere. I am, Sir, Your obedient servant, A Student’s Friend, Bethnal* green, Aug. 28. THE CHEMIST. 409 DISTILLATION. Art. III. FERMENTATION. Perhaps the most difficult part of the whole process of procuring a good spirit consists in making the materials from which it is to be extracted undergo a proper de¬ gree of fermentation. On this de¬ pends the quantity of spirit formed by the grain ; the quantity extract¬ ed, indeed, will depend on what is properly called distillation. We know of more than one instance in which the results completely dis¬ appointed expectation, in conse¬ quence of the fermentation not having been completed. No spirit can be obtained from grain until it has been fermented ; this part of the process is therefore essential, and it is necessary that its prin- cipl es should be known. It is a striking distinction be¬ tween the substances belonging to the animal and vegetable kingdom, and minerals, that the former are subjected to perpetual alteration, while the latter, if left to them¬ selves, remain almost unchanged, or change so slowly that the altera¬ tion is scarcely perceptible to our senses. Vegetables and animals, while living, grow and decay; and when dead, unless under very pe¬ culiar circumstances, invariably undergo spontaneous decomposi¬ tion. Chemical researches have demonstrated, that during the life¬ time of plants the substances of which they are composed are con¬ tinually changing their, nature. Mucilage in the young plant be¬ comes starch in an old one, and the acid of the green fruit, as the season advances, is gradually con¬ verted into sugar. The constituent parts, then, of plants are gradually entering into new combinations and forming new compounds. This holds good after the plant has been taken from the earth and the fruit gathered from the tree. Our readers have all witnessed the change which a cabbage or some similar vegetable undergoes when taken from the ground ; its leaves gradually decay: if thrown in a heap, and not exposed to some drying influence, they soon become moist, and after a short time emit a most noxious effluvia, a part of their constituents separating in the form of gas occasions an intoler¬ able smell. This species of spon¬ taneous decomposition is called putrefaction. On the other hand, when the odour is not offensive, when the products are applied to useful purposes, when the circum¬ stances under which the process takes place are effected by art, though the decomposition may still be called spontaneous, the name of fermentation has been given to it. For a long period, the nature of these changes was involved in utter darkness; but since chemis¬ try has been applied to analyze the substances found both in the living and the dead vegetable, and in the products of its decomposi¬ tion, some light has been thrown on this curious phenomenon, though it cannot yet be described as per¬ fectly known. As the ultimate 410 THE CHEMIST. constituents of all vegetable mat¬ ter are oxygen, hydrogen, and car¬ bon, all the products of the fer¬ mentation of vegetable substances are merely new compounds of these three elements. Lavoisier was the first chemist who instituted a series of experiments on right principles to investigate the phenomena of fermentation ; and since then the same subject has been pursued with considerable success, though with little alteration in the results, by M.Thenard and M. Gay Lussac. The phenomena of vegetable de¬ composition vary in some measure, according to the nature of the sub¬ stance decomposed. With this variety we have, on the present occasion, nothing to do, but shall content ourselves with describing that change in vegetables, the re¬ sult of which produces intoxicating liquors, and w hich is known by the name of vinous fermentation. When thejuiceofgrapes, which is called must, is expressed, and left in a temperature of about 70°, it soon becomes thick and muddy, its tem¬ perature increases, and carbonic acid gas is evolved; in a few days the fermentation ceases, a thick part subsides to the bottom, a scum rises to the surface, the liquid loses its sweet taste, becomes lighter, and is the substance well known under the name of wine. On analyzing must, it is found to consist principally of water, sugar, jelly, gluten, and tartaric acid, the quantity of sugar being very con¬ siderable, though varying in dif¬ ferent grapes. Wine, however, is found to consist principally of an acid , alcohol, extractive matter , a vo¬ latile oil, which gives it its peculiar flavour, and a colouring matter. The alcohol obtained from wine by dis¬ tillation, as it is found in com¬ merce, in its dilated state, is called brandy. No alcohol can be de¬ tected in must before fermentation. Grain, whether malted or not, when infused in water at a certain tem¬ perature, undergoes a change like the fermentation of must, hut the resulting liquid, though it contain alcohol, is not, without farther preparation, fit for use. We have at present nothing to do with that farther process, by which the malt, after being infused and changed into wort, is converted into beer; and shall strictly confine ourselves to describing the process w hich we understand to be used by the dis¬ tillers. In this country the distillers make use of both malt and grain, the proportion of the former vary¬ ing from a third to a tenth part of the latter. This mixture is ground, or the malt is merely bruised and mixed with barley already ground to meal. To one bushel of this mixture from 12 to 13 gallons of water are added, at a temperature of about 150° Fahr., and the whole is subjected by mechanical means to considerable agitation, which constitutes the process of mashing. This is kept up for some time, anti the heat preserved by the addition of seven or eight gallons of w ater, a few degrees under the boiling temperature. The infusion is called wort , is very sweet, but not quite so sweet, nor is it so clear, as that made from malt. The starch, therefore, of the grain seems to he converted by the mashing, as in the process of malting, to the na¬ ture of sugar. The wort, after being allowed to settle, is drawn oft' and cooled very rapidly, in ex¬ tensive wooden troughs, or it is made to traverse a pipe immersed in cold water; more boiling water is then poured on the grain to ex¬ tract all the saccharine matter possible. The portion of water which is poured the third time over the malt is generally reserved to be poured over fresh grain, or it is concentrated by boiling. It may be here remarked, that there is no species of manufacture which, on account of the taxes levied on it, has been so much restrained, im¬ peded, and injured in this country by numerous and injudicious fiscal regulations as that of spirits. Fortu¬ nately for mankind, the love of gain has been too strong or too cunning for the wit of the legislator, and the art has been found of circumvent¬ ing him, to the great benefit of the world. , It is quite evident, if THE CHEMIST. 411 a tax were laid on cotton cloth, which, for the sake of collecting this tax, prescribed that all the threads should be of one specific thickness, and all the webs of one specific strength, we could have none of that variety of texture by which every taste is now gratified, and every purpose answered by the products of our looms. Now the manufacture of spirits has been subjected to restrictions analogous to those we have supposed to be laid on cotton. Thus the distiller is obliged, as a consequence of the law, to make his wort of a certain specific gravity, and to obtain from that a certain quantity of spirit of a specific strength. We shall boldly assert, that this is the reason why, wdien our knowledge of the chemis¬ try of distillation has been so ex¬ tensively increased, the spirit ma¬ nufactured in our country is, cgoi- pared to that manufactured in other countries, inferior both in flavour and goodness ; why, for example, common English gin is so decidedly inferior to good smug¬ gler-made malt whisky and to the gin made in Holland. In this latter country the mode of levying the tax does not compel the manu¬ facturer to concentrate his worts so much, nor to distil so rapidly, nor to make precisely such and such a quantity, or pay for it whe¬ ther made or not; and hence he makes a liquor to suit the health and taste of his customers. Under a pretence of benefiting people, legislators restrict them to the use of a liquor which is both compara¬ tively disagreeable and unhealthy. The mode in which the distillers strengthen their wort, is to add to it an almost saturated solution of barley and malt in hot water, till it has attained the requisite strength. It is calculated, that to obfrin a gallon of spirits of the specific gravity of 0.91917, which contains 4.61bs. of alcohol, 9.21bs. of sugar must be decomposed. But as the distiller cannot count on decom¬ posing above four-fifths of the sac¬ charine matter of wort, he is com¬ pelled to raise the strength of his wort so that it may contain lUlbs. of saccharine matter for every gallon of spirits, which, whe¬ ther made or not, he must pay duty for. After the distiller has thus pre¬ pared and cooled his wort, it is run into the fermenting tub ; the temperature is between 65° and 70°, according to the quantity, the season of the year, and the opinion of the distiller. Its specific gravity varies, being never less, we believe, than 1.069, and so great as 1.110. The best yeast which can be pro¬ cured is added, in successive por¬ tions, during three days, and the quantity amounts to about one gal¬ lon for every two bushels of grain and malt. In three or four days the temperature rises to about 80, and sometimes to 90; great quan¬ tities of carbonic acid are disen¬ gaged, and the liquid becomes lighter. In about six or eight days the fermenting tubs are closed up, and at the end of ten or twelve days the fermentation is completed. The specific gravity of the liquid is now probably not higher than 1 .000, and consists of alcohol mixed with undecomposed saccharine and farinaceous matter. The larger the proportion of alcohol, the greater the quantity of sugar, which is so much waste occasioned by the laws obliging the distiller to make his wash of a certain strength. Wort, or the mere infusion of malt and grain, is a liquid of a brownish co¬ lour and of a sweet luscious taste. When chemically examined, it ap¬ pears to consist of a saccharine mat¬ ter , analogous to sugar, starch , gluten, and mucilage. The principal alteration, therefore, which the wort has undergone by fermenta¬ tion is, like the alteration in must by the same process, the conver¬ sion of the saccharine matter into alcohol. Wort, however, unlike must, will not ferment without the addition of yeast. It becomes, therefore, a matter of curious in¬ vestigation to know what yeast imparts to the wort to induce the commencement of this process. It was ascertained by Fabroni, that a substance analogous to gluten was necessary to fermentation; 412 T1IE CHEMIST. such a substance can be extracted from must, and it exists ready formed in the grape, though pro¬ bably it is separated from the sac¬ charine part by being lodged in the membranous part of the grape. After this substance was extracted, gluten was found to promote the fermentation, and Thenard and Seguin have found that all juices which undergo spontaneous fer¬ mentation contain a similar sub¬ stance. It has been also ascer¬ tained that yeast contains a large quantity of a substance resembling gluten, and that if this is separated it loses the property of exciting fermentation. This peculiar sub¬ stance existed in the grain, but underwent modifications during the process of mailing and during the fermentation of the beer from which the yeast is separated. The changes which take place in the juice of fruit, or in the conver¬ sion of wort into wash or, beer, have been thus explained: — It has been found that sugar dissolved in four times its weight of water, mixed with yeast, and plaeed in a proper temperature, ferments pre¬ cisely as wort does, and yields the same products. Chemists, there¬ fore, have made experiments on it, as a more easy manner of deter¬ mining the phenomena. Thenard mixed GO parts of yeast and 300 of sugar, and fermented them hi a temperature of 59°. In four or five days the saccharine matter had disappeared, and 94.G parts by weight of carbonic acid were evolv¬ ed. On distillation the fermented liquor yielded 171.5 parts of alco¬ hol, spec. grav. 0.822; by evapora¬ tion 12 parts of a nauseous acid substance were obtained, and 40 parts of the yeast, deprived of its azote, remained, and there was a loss of 41 .9 parts. Now as sugar is composed proportionally of 5 oxygen, G carbon, and 5 hydrogen, and as alcohol is a compound of 1 oxygen, 2 carbon, 3 hydrogen, it is supposed that the action of the yeast, which has a strong affinity for oxygen, is to take some of it from the saccharine matter, and that when the decomposition is once begun, it afterwards goes on by itself, the sugar losing in the process oxygen and carbon, which unite and escape in the shape of carbonic acid gas. Whether or not this is a correct explanation of the phenomena we will not decide, but it has probability in its favour. 