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The following is the order of the affinities offulphuric acid. Barytes, ftrontian, potafh, foda,lime, magnefia, ammonia, glycine, yttria,alumine, zircon, metallic oxyds.

The ufes of fulphuric acid are numerous andvery important. It is employed in tire labora-tory in the preparation of the nitric, muriatic,fluoric, phofphoric, and many other acids; itis a ufeful agent in various proceffes of chemi-cal analyfis. It is largely ufed in the arts, par-ticularly by the dyer and callico-printer, and isof no fmall importance as an article of themateria medica.

SULPHURIC ACID, fuming, or Glacial.

In the preceding article we have briefly no-ticed fome of the charadteriftic properties ofthe glacial fulphuric acid, or that obtained fromthe diftillation of calcined fulphat of iron: wenow proceed to relate them more at large, ashaving been the occafion of much controverfyamong the continental chemifts, particularlythofe of Germany . This acid ufed to be, andperhaps is ftill, prepared at Nordhaufen inSaxony ; it is of a dark brown colour, and ex-hales, when expofed to the air, abundance ofdenfe white fuffocating vapours; its ufualfpecific gravity is = 1.95. When diftilled ina glafs retort, by the time that a fmall portionhas come over, the remaining acid is nearlycolourlefs, and of a fomewhat lefs fpecific gra-vity than the entire acid; it no longer exhalesany vapours, and except in fuperior denlity, ittdoes not appear to differ from the commonfulphuric acid. The fluid and vapour containedin the receiver as they cool down gradually tothe temperature of the atmofphere, begin tocongeal; the vapour forms radiated cryftalson the top and fides of the receiver, while thebottom is occupied with a confufedly eryftallinemafs, differing in denfity according to the fpe-cific gravity of .the acid before diftillation.Hence it is obvious, that the fuming acid ofNordhaufen, differs from common acid in be-ing mixed or combined with a cryftallizablefubftance more volatile than fulphuric acid.This fubftance was fuppofed from its fuffocat-ing odour to be fulphurous acid, accordingly,experiments were made by M. Dollfufs and.others, >to reftore the clear rectified acid to its• former (late, by digefting it with charcoal, faw-duft, oil, alcohol, and other deoxydating fub-ftances; but though the acid by this means ac-quired a brownifh black colour and a fulphur-ous odour, it was hardly at all fuming when.expofed to the air; and on diftillation it af-

forded a weakly acid fulphurous liquor, whichneither congealed nor emitted white vapours.From the refults of thefe experiments M. Doil-fufs concluded that the fuming and glacial qua-lity of the Saxon fulphuric acid was owing tothe prefence of a peculiar volatile fait.

In order more compleatly to elucidate thematter, a feries of experiments was undertakenby M. Morveau. He took 4lbs. of green vi-triol, and by careful calcination reduced itsv,'eight to 28 ounces; thefe were put into anearthen-ware retort and diftilled at the full heatof a reverberatory furnace. When the retortbegan to grow red, a weak acid came over indrops during about half an hour; the receiverwas .then changed, and as the heat increafed,white vapours began to make their appearance.To the receiver was attached a pneumatic ap-paratus, in order to colleft the gas produced,which being examined from time to time it ap-peared, that during the firft three hours, littleelfe came over than atmofpheric air, which wasthen fucceeded for the next hour and a half byfulphurous acid gas either pure or at leaftmixed with no oxygen; by degrees .however itbecame diluted with oxygen gas, and during thenext four hours and a half (after which theprocefs was put an end to) a large quantity ofoxygen gas was produced, mixed however dur-ing the whole time with fulphurous acid.The fluid in the receiver was of a brown co-lour, and being expofed during the night to atemperature of 47® Fah. was found in themorning to be congealed into a folid mafs ofcryftals, with the exception of a few drops of abrown ^liquid. "T -

As foon as the receiver was feparated fromthe retort, it was inftantly filled with white va-pours which .poured out fo rapidly as in a fhorttime to fill the whole laboratory; thefe fumes,though fomewhat fulphurous, were by nomeans fuffocating. A few drops of water beingfprinkled on fome of the concrete acid, caufeda hilling noife like that of a bar of iron plungedin cold water, and the acid immediately meltedand entirely loft its fuming property. If theftopper of the veflel in which the glacial acid iskept be often taken out, the cryftals at lengthrefolve themfelves into a brown liquor, and ifthis is again fubje&ed to diftillation therecomes over an acid, at firft highly fulphurous,but becoming lefs fo as the procefs goes on;no portion however of the diftilled produft .isin the leaft degree fuming or congealable at thecommon atmofpheric temperature.

From thefe facts it appears probable that the