TEA.

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SULPHURIC ACID. A valuable improvement of the process for manufacturingthis fundamental chemical agent has been lately contrived by M. Gay Lussac, andmade the subject of a patent in this country by his agent M. Sautter. It consists incausing the waste gas of the vitriol chamber to ascend through the chemical cascade ofM. Clement Desornes, and to encounter there a stream of sulphuric acid of specificgravity l - 750. The nitrous acid gas, which is in a well-regulated chamber alwaysslightly redundant, is perfectly absorbed by the said sulphuric acid; which, thus im-pregnated, is made to trickle down through another cascade, up through which passesa current of sulphurous acid, from the combustion of sulphur in a_ little adjoiningchamber. The condensed nitrous acid gas is thereby immediately transformed intonitrous gas (deutoxide of azote) which is transmitted from this second cascade into thelarge vitriol chamber, and there exercises its well-known reaction upon its aeriformcontents. The economy thus effected in the sulphuric acid manufacture is such thatfor 100 parts of sulphur 3 of nitrate of soda will suffice, instead of 9 or 10 as usuallyconsumed.

Upon the formation of sulphated nitrous gas (N Os, 3 S 03, 2 H O), and its com-bination with oil of vitriol, the manufacture of hydrated sulphuric acid is founded.Either sulphur is burned in mixture with about one ninth of saltpetre; whence alongwith sulphurous acid gas, nitrous oxide gas is disengaged, while sulphate of potashremains; thus K 0, N 0" + S = S 03 -|- N Os, IC 0. 2. Or, nitric acid in the fluid orvaporous form may be present in the lead-chamber, into which the sulphurous acidgas passes, in consequence of placing in the flames of the sulphur a pan, charged witha mixture of sulphuric acid and nitre or nitrate of soda. This nitric acid beingdecomposed by a portion of the sulphurous acid, there will result sulphuric acid andnitrous gas. By the mutual reaction of the sulphurous and nitric acids, sulphuricacid and nitrous gas will be produced: N 0 3 -j-3 S 0 - - ,\ 02-j-3 S 03. 3. Or,by heating sugar or starch with nitric acid, the mixture of nitrous gas and nitrousacid vapor which results, may be thrown into the chamber among the sulphurousacid. In any one of these three cases, sulphurous acid gas, nitrous acid vapors (pro-ceeding from the mixture of nitrous oxide and atmospherical oxygen) and steam aremingled together; whence arises the crystalline compound of sulphated nitrous oxidewith sulphuric acid, which compound subsides in white clouds to the bottom of thechamber, and dissolves in the dilute oil of vitriol placed there, into sulphuric acid,with disengagement of nitrous gas. This gas now forms, with the remaining atmo-spherical oxygen, nitrous acid vapors once more, which condense a fresh portion ofsulphurous acid gas into the above crystalline compound; and thus in perpetualalternation.

Sulphurous acid gas does not act upon nitrous gas, not even upon the nitrous acidvapor produced by the admission of oxygen, if water be absent; but the moment thata little steam is admitted, the crystalline compound is condensed. The presence ofmuch sulphuric acid favors the formation of the sulphated nitrous gas. These crystalsare decomposed by tepid water with disengagement of nitrous gas, which seizes theoxygen present and becomes nitrous acid (hyponitric of many chemists).

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TEA. This well-known plant has recently acquired peculiar interest among menof science, both in a chemical and physiological point of view. In its composition it ap-proaches by the quantity of azote it contains to animalized matter, and it seems therebyqualified, according to Liebig , to exercise an extraordinary action on some of the func-tions of animals, especially the secretion of bile. The chemical principle characteristicof tea, coffee, and cocoa-beans, is one and the same when equally purified, from which-ever of these substances it is extracted; and is called indifferently either theine orcaffeine. Mulder takes it from tea, by treating the evaporated extract hy hot water,with calcined magnesia, filtering the mixture, evaporating to dryness the liquor whichpasses through, and digesting the residuum in ether. This solution being distilled,the ether passes over, and the theine remains in the retort. This principle is extractedin t l .'e same way from ground raw coffee and from guarcma, a preparation of theseeds cf panllinia, highly valued by the Brazilians. Theine , when pure, crj r sta]lizesin fine glossy needles, like white silk, which lose, at the heat of boiling water, 8 per;ent. of their weight, constituting its two atoms of water of crystallization. Theseneedles are bitter tasted. They melt at 350- F., and sublime at 543° without decom-posing. The crystals dried at 250° dissolve in 98 parts of cold water, 97 of alcohol,and f94 parts of ether. In their ordinary state, they are but little more solublein these menstrua. Theine is a feeble base , and is precipitable by tannin alone fromits solution.