Experiments on hepatic air ... : Read at the Royal Society, December 22, 1785 / [Richard Kirwan].

  • Kirwan, Richard, 1733-1812
Date:
1786
Catalogue details

Licence: Public Domain Mark

Credit: Experiments on hepatic air ... : Read at the Royal Society, December 22, 1785 / [Richard Kirwan]. Source: Wellcome Collection.

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    The above experiment feems to fhew that liver of folphtir will not yield hepatic air without the addition of an acid ; and I believe this to be true when the experiment is made in the dry way, and nearly fo in the moiit way ; for having added 200 grains of fulphur to a concentrated folution of ftrong cauflic vegetable alkali, by a ftrong and long-continued heat I obtained only 1 cubic inch of hepatic air ; yet it is well known, that a flrong folution of liver of fulphur confiantly emits an hepatic fmell, even in the temperature, of the atmofphere ; and the fubftance fo emitted contains fo much hepatic air as to difcolour filver and lead, and even their folution s; wrhich fhews, that an incomparably fmall quantity of this air is capable of producing this effedfc. To difcover whether this extrication of hepatic air might be caufed by the depofition of fixed air from the atmofphere, 1 threw fame pulverifed calca¬ reous hepar into aerated water, and by the application, of heat endeavoured to obtain hepatic air, but in vain : and, indeed^ the very circumftance that the hepatic fmell, and its effects, are always ftrongefl the firfh inflant that a bottle of the hepatic folution is opened, feems to indicate that fixed air is no way concerned in its produftion. The beft liver of fulphur is made of equal parts of fait of tartar and fulphur; but as about one-fifth of the fait of tartar confifls of air which efcapes during the operation,, it feems, that the proportion of fulphur predominates in the refulting compound; yet as fame of the fulphur alfo fublimes and burns, it is not eafy to fix the exact proportion, ioo grains of the; beft, that is, the reddeft liver of fulphur, afford, with dilute marine acid, about 40 cubic inches of hepatic air, in the tem¬ perature of 6o° : a quantity equivalent to about 13 grains of fulphur, as will be feen in the fequel. The