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MANUFACTURE OF SUL latter end of the sixteenth century,

PHURIC ACID... and up to the early part of the 000) (ENGLISH METHOD.). 18th it was wholly obtained from 22 SULPHURIC acid is a compound sulphate of iron, or the green vitriol of the two simple substances ox- of commerce; and hence sulphuric ygen and sulphur, in the proportion, acid was improperly called oil of by weight, of three oxygen and two vitriol. Dr. Ward then introduced sulphur. As it is usually met with the method of obtaining it by burnin commerce, it is in a liquid form, ing sulphur and nitre; and enjoyed which is owing to the water com- the monopoly of this manufacture bined with it, and for wbich it has for several years. In 1746, Dr. a very strong affinity. At Nord- Roebuck, an eminent and scientific hausen, in Germany, a very much physician, began at Birmingham concentrated sulphuric acid is ob- the practice of burning the sulphur, tained from the distillation of green and receiving the product in leaden vitriol, and if this, put into a glass chambers. That reduced the price retort, be distilled by a modes of the article one-fourth, and allowrate heat, and received into a ves- ed it to be employed for a variety sel surrounded by ice, sulphuric of purposes from which it was bejacid is obtained in a solid state. fore excluded by its great cost.

It is tough, and resembles asbestos Since that time manufactories of sin its appearance. When exposed to sulphuric acid on this principle the air it fumes, and gradually flies have been established, on an extenoff in vapour. In the solid state its sive scale, in several parts of the properties are not known, and it is kingdom.. put to no use ; but when united In England it has not yet been setwith water, in various proportions, tled whatdimensions are the best for it is perhaps the most useful of all the leaden chambers; the manu. the agents employed by the che- facturers construct them according mist, and more used in the arts and to their convenience; and Mr. s manufactories than any other acid Parkes* (whose account we are now sexcept the acctic, We propose, abridging,) mentions one in Lan

therefore, in the present paper to cashire, who builtseveral rooms 120

give a short account of the mede by 40 feet, and 20 feet high. Whatdof manufacturing it on a large ever may be the size of the chamjščale, as now carried on in various bers, the process is conducted in

parts of France and England, i the following manner : Common no1 The diluted sulphuric acid, or brimstone, coursely ground, is mix

the hydrate of sulphuric acid, as it is called, has beca known since the : *! Chemical Essays,” vol. I. p. 484.

ed with saltpetre in the proportion have been substituted for the glass of eight pounds of the former to one retorts, and have been found to of the latter; and the mixture is save fuel and quicken the progress spread on leaden or iron plates, of concentration. Mr. Parkos menplaced on stands of lead within a tions that he had a platinum vessel chamber wholly lined with lead constructed for rectifying sulphuric and covered at the bottom with a acid some years ago; it cost some thin sheet of water. About one hundred pounds, but answered the pound of the mixture is allowed to purpose perfectly well. The sul-, every three hundred cubical feet phuric acid of commerce always of atmospherical air contained in contains sulphate of potash, derived .. each chamber; and when a charge from the nitre, and sulphate of lead ; in this proportion has been placed derived from the lead used in the in one of them, the mixture is process. lighted by means of a hot iron, and In order that this method should the door is closed. The combustion succeed, it is essential that ox. of the two substances, if well mixed, ygen be present to maintain the continues about forty minutes. In combustion, that the chamber do about three hours the gas is all not allow the volatile matter which condensed, and the chamber is arises to escape, and that water thrown open to admit'atmospberic be present to absorb it. For a long in air, and prepare it for another time, however, the rationale of this burning. The plates are again method was involved in doubt and charged, and the same process is obscurity. It was found that 100.4 repeated every four hours, without parts of nitre, containing only 39,11 intermission either by day or night, of oxygen, when combined with the i until the water at the bottom of the requisite quantity of sulphur, prochamber is thought to be sufficiently duces a quantity of sulphuric acid," tai acidified. This is judged of by the containing 1200 parts of oxygen. acid turning black, when it is drawn Moreover, after the combustion of off by means of a syphon into a re- the sulphur, the residuary salts con- ! . servoir of lead It is then concentrat- tain nearly as much oxygen as was to ed by the aetion of heat in leaden originally contained in the nitre ; non boilers, until it has acquired such and the 1200 parts of oxygen in the w a specifc gravity as best suits the acid could not be accounted for, at manufacturer's purpose. It is At length Messrs. Clement andre afterwards boiled in glass retorts Desormes, two manufacturing till all the sulphurous and nitric French chemists, succeeded in a acids are driven off, and it is fit for explaining this circumstance, and me the market. The necessity for the their explanation has since been tot concentration by means of heat, confirmed by Mr. Dalton and Sirje arises from the water, after it has H. Davy. They supposed that the a taken up a certain quantity, refus- burning sulphur, taking from the si ing to absorb the acid so readily as nitre a portion of its oxygen, forms at first. Care, too, must be taken sulphuric acid, which, uniting is when the acid is in the leaden with the base of the nitre, or boiler that it be not too much con- potash, displaces nitric and nitrous 0097 centrated, for the boiling point of acids in vapour, which is decom mucho concentrated acid, and the posed by the sulphurous gas into 191 melting point of lead are so near to nitrous gas or deutoxide of azote, te each other, that the leaden boiler Being naturally only a little heavier may be destroyed. Some manufactu- than air, and being then rarefied by our rers remove it at once into the glass the heat, the nitrous gas rises to the retorts, and do not steam it in lead,' roof of the chamber, and there in which prevents the acid combining coming into contact with atmo, 0 2 with so large a quantity of this me- spherical air, by means of a hole, tal. Lately, too, platinum alembics, and without which the mangfactu. placed within pots of cast iron of a "rers found that the acidification corresponding shape and capacity, 'would not go on, forms nitrous acid

vapour, which, being a heavy body, ON RESPIRATION, AND THE immediately precipitates on the · PRODUCTION OF ANIMAL .. sulphurous flames. Sulphuric acid HEAT. and nitrous gas are again formed, In our 19th Number we published and the latter again mounts for a a little article, showing the effect new charge of oxygen, again to re- of evaporation in preserving bo. . descend and transfer it to the sul. dies, animals as well as others, at " plur. Sir H. Davy has since about blood heat, when every thing shown that water is necessary to around them is at a much higher the mutual action of sulphurous temperature. This is a chemical gas, and nitrous gas, and that phenomenon ; for every thing reunless this fluid be present the lative to the production of heat process does not go on. With falls into the department of chethis additional fact it would mistry. Admitting that evapora.. appear that a small volume of tion is sufficient for this when the nitrous vapour, by its alternate and body is in a medium considerably ! frequent changes into oxide and hotter than itself, the question ocacid, is capable of acidifying a curs, What is it which preserves great quantity of sulphur. We the human body and other animals shall now describe the plate, which at a high temperature when they may serve to give our readers exist in a much colder medium? some idea of a sulphuric acid ma- Is this, too, a chemical phenonufactory. We have borrowed it menon? We believe it is; but. from the valuable work of Mr. many of our readers may perParkes, entitled “ Chemical Es- haps be disposed to doubt the says."

fact. They constantly experience in It is the representation of the sensations of heat and cold, in yard of a sulphuric acid manufac- every part of their body, and tory, walled round with all its re- may therefore not exactly comprequisite buildings: AAAA are cham- hend what we meau, or doubt, bers of combustion made with sheet our assertion. We do not at prelead; B, the main reservoir, also sent allude to what they feel, but of lead, to contain the acid drawn to the state of the thermometer froin the chanibers; C, a trough when brought into contact with the lined with lead, to convey the acid human body. We beg them, there. to the reservoir. The acid is drawn fore, for the moment, to forget the by a syphon from the chamber into piercing winter's blast, and the od the trongh; D, a punip to supply melting summer's sun, and to think the leaden boilers, EEEEE, with only of the expansion of mercury, no acid from the reservoir. These It is, then, a very remarkable fact, it boilers are for concentrating the which has been verified by repeated in acid. They are placed under a observations, that when a thermo. 've roof supported by pillars at the meter is placed under the armpit, dots, marked F. G, the reservoir under the tongue, or in any posifor the concentrated acid, provided tion so as to be affected only by with a close cover to prevent the the heat of the body, it always , acid absorbing moisture; H is the stands, in all climates, in all situa. ; room where the acid is still further tions, and with whatever person the concentrated by boiling in glass experiment is made, about the same is retorts ; I, is an open shed, sup- heiglıt, or about the 98th degree. ported on pillars, for packing, &c.; There is some little variation from K, a warehouse ; ''L, counting this. The temperature of infants, us! rooms MN, store rooms; 0, is somewhat lower; and there are pounding room; P, stable; Q, cases of disease recorded, particu- s i small Jaboratory; R, entrance; larly one by Dr. Prevost, of Geneva, S, coal store; T, pump for supply in which the temperature of the ing water; U, another pump; W, body was much higher. But in a large storehouse.

general the mercury stands at the end (French Method in our next.) ; same mark. "Among the phenomin'

mena," says M. Despretz, a French spiration in contributing to the pro-author, to whose paper, On ani. duction of animal heat has been mal heat," a prize was awarded generally admitted, though his by the French Institute, in 1823, theory of respiration has been dis

which the study of physiology puted. That the two are intimateoffers to our view, there is no one ly connected, is by no man now more capable of exciting our atten- denied; and therefore our readers tion, than the extraordinary pro- will see the propriety of our having perty with which man and all hot here united them in one article, blooded animals are endowed, of meaning, as briefly as possible, to preserving a temperature nearly give an outline of both. equal, though the media around There have been various theothem undergo continual variations. ries of the process of respiration; From the very beginning of expe- but without discussing them, we rimental physiology, enlightened shall merely state the best estainquirers, such as Haller, Hunter, blished facts. The atmosphere is Bichat, Le Gallois, Dr. J. Davy, composed by measure of about 21 and others, have sought after the per cent. of oxygen, the remainder cause of this extraordinary pheno- being azote, or nitrogen, about menon, and have contributed to one per cent., in the driest weather, explain it. But though this par- of aqueous vapour, and about the ticular fact is so extraordinary, it thousandth part of the whole being falls so little under the notice of carbonic acid gas. All other aerial ordinary men, that they, judging mixtures and gases are in a shorter by their sensations, imagine their or longer time destructive of life.

bodies vary in temperature like Some cannot be respired at all; - the things around them. At the others again can be respired for a

same time, there is no person so short time, but life cannot be long unobserving or so uninformed as sustained by breathing any air but not to know that animals possess the mixture which constitutes the a power of generating and creating atmosphere. The first well aseerheat. It is this power which pre- tained fact is, that all animals in

serves the temperature of the body breathing the atmosphere vitiate 9 at the same point, when other ob- the air; a portion of oxygen dis

jects are much colder. In fact, appears, and a portion of carbonic though the production of animal acid gas is formed. They take oxheat is known to every man, it is ygen gas into the lungs, or some so extremely familiar, he having corresponding organ, and give out felt it long before he had a capacity carbonic acid gas. This fact is infor making remarks, it having variably accompanied by another, glowed in his cheek with his first namely, that the blood, entering exertion, and been felt at his first the lungs by the pulmonary artery, blush, that very few persons ever changes its colour from dark purtbink of inquiring into its cause. ple to bright red, loses the properIt has been said, that a man is fitties of venous, and becomes artefor a metaphysician when he once rial blood. There cannot be any doubts the existence of matter; doubt that this change in the blood and a man seems, in like manner, is the consequence of inhaling fit for an inquirer, who asks himself oxygen gas and exhaling carbonic how the heat is produced which acid gas. As carbonic acid gas never allows him, during life, contains its own volume of oxygen though exposed to the greatest de gas, and as the quantity expired is gree of cold, to sink down to the in general nearly equal to the temperature of ice. The fact is so quantity of oxygen which disapfamiliar, that every man supposes pears, it has been supposed, and he can explain it, till he makes the this is the theory most generally attempt; and then he finds, indeed, adopted at present, that the ox

great difficulties. Ever since the ygen inhaled goes immediately to ja time of Lavoisier, the effect of re- convert the carbon of the venous

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blood into carbonic acid gas, and large quantity of azote. It is, howthat consequently no oxygen gas ever, quite clear that it is inhaled, is absorbed by the blood. Dr. Ed- or taken into the lungs, as well as wards, however, has lately shown, the oxygen with which it is mixed; from a variety of experiments, de- and some late experiments of the scribed in his work, “De l'Influences gentleman we have just mentioned, des Agens Physiques sur la rie," that as well as some previously made the carbonic acid gas expired does by Messrs. Allen and Pepys, make not always equal the quantity of it probable that it is absorbed; the oxygen inspired; and he has, more- quantity absorbed and the quanover, shown, by making animals tity exhaled being, in ordinary ocbreathe, for a short time, air in casions, about equal. Admitting which there is no oxygen, that they this, it does not still explain the even then expire carbonic acid use of azote in the atmosphere; gas; whence he coneludes that the and we want to know what change oxygen inspired is absorbed by the it undergoes, if any, and what is blood, which at the same time gives the use of absorbing and giving out carbonic acid gas. This fluid, out equal quantities of this fluid. he supposes, exists in the blood, The particular experiments which ready formed; and in support of seem to decide 'the question, was this view, he mentions the circum- making animals breathe air in stance of carbonic acid gas having which there was little or no azote, been found in the mass of the its place being supplied by hydroblood. Between these two expla- gen, when it was found that hydronations, we must leave the reader gen was absorbed and azote exto decide for himself, remarking, haled. M.Despretz, however, whose that at present the latter appears name we have already mentioned, to us the more probable, but re- denies the absorption of azote, quires to be confirmed by further though he admits its constant exexperiments. Whichever of the halation, and mentions the expeexplanations, however, may be riments of Magendie, which show adopted, the great fact is still the that the azote is derived from the same, the oxygen of the atmosphere food, and that animals cannot subis taken into the lungs, and a quan- sist on food wholly destitute of tity of carbonic acid gas, about azote. About this part of respiraequal, on ordinary occasions, to tion, then, there is a doubt; and it the oxygen which disappears, is remains for future discoverers to given out. A common sized man decide how and for what purposes consumes about 46,000 cubic inches all this quantity of azote is employof oxygen per day, and makes ed. The probabilities are in favour about twenty respirations in a mi- of the absorption, and 'its gradual nute, but these circumstances vary conversion into the constituent in different individuals. It has also parts of the body; but in this sup. been found, that several circum- position, how the exhaled azote is stances influence the production of produced, must still be accounted the carbonic acid gas in the same for. The alternate inhalation into; individual. Thus it is diminished and exhalation of air from the by taking intoxicating liquors, lungs, with the changes described, living on vegetable diet, and by constitute the function of respira. using large quantities of mercury tion. or nitric acid.

The question now occurs, How As in general no alteration takes does this process generate heat ? place in the quantity of azote con- It is known that the habitual tem. Tained in a specific quantity of perature of an animal is high in atmospheric air which has been proportion as his respiration is breathed by animals, it has been active, but how does inhaling and in general concluded that it was expiring air preserve the body at not absorbed, and there have been about an equality of temperature, many doubts as to the use of this and carry that heat to the farthest ..

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