On the different Gafcs. ji^g 



unfit for refpiration. He knew alfo the ammoniacal as well 

 as the muriatic acid gay, and the fulphuric acid gas, and 

 had learned, from his own experience, that the latter can 

 be as ftrongly comprefl'ed as common air. He knew alfo 

 that metals increafe in weight bv calcination, and again 

 decreafe r)n being revived ; for he found that red lead in the 

 preparation had increafed in weight about a twentieth part, 

 and by a ilrong heat gave a great deal of air: his own ex- 

 perience had taught him alio that phofphorus, fulphur, and 

 a tallow candle, abforb fome of the air in which they burn, 

 as animals abforb fome of the air in which they breathe ; 

 though he afcribcd the pernicious change which the air 

 thereuy experiences, not to the lofs it fullains, but rather 

 to the corrupt evaporation with which it is filled. He 

 liad obferved, though lefs pcrfe«9:ly, that phofphorus after 

 combuftion increafed in weight by imbibing fomething 

 from the atmofphere. He had difcovered that an aeri- 

 form fubftance was contained in acidulous waters, and 

 that air was continually abforbcd by plants in a healthy 

 Hate *. 



In this difficult doctrine, however, he left a great deal to 

 be explained by his followers; for he did not define and was 

 not acquainted with the difference of many of the gafes, and 

 fome of them efcaped his notice altogether. The further illuf- 

 tralion of them was referved for the modern chemills. Thus, 

 in particular, the following authors have vcrv much contri- 

 buted to enlarge our knowledge of the carbonic acid : — . 

 Dr. Black in Medical and Philofophical Commentaries, by 

 a Society in Edinburgh, vol. ii.; Dr. Macbride in Experi- 

 mental Eflays on Medical and Philofophical Subjects, Lon- 

 don 1764. 8vo; T. Henry in his Experiments and Obferva- 

 tions, London 1773. 8vo.; T. And. Emmer in D'lffcrlalh de 

 Acre fixo feu Ac'ido dereo, Edin. 1784; and the Dutch 

 naturalift D. Dc Smedt in D'lD'crtath de Aerc Jixo, Ultraj. 

 1773. S\'^' Among the Germans, N. J. Jacquin in Examcn 

 Chem'icum Tiottrlua: MtytTiaiuc dc Acido pinguiy ct Blacki~ 

 an^ de Acre Jixo rtj'peSiu Caleb, Vindob. 1769. 8vo ; and 

 the late J.J. Well, m his Defence of Dr. Black's Dodrine 

 relpc<!^ing fixed Air, againd the (.)l)jc6lions made by Wicg- 

 lel), Vienn;i 1771. 8vo.; and on The Caufes of the healing 

 of unflaked Lime, Vienna 1772. 8vo. Among the Ita- 

 lians, I''. K, Foiitana in his I'hyfical Rofcarchcs rcfpefting 

 fixed Air, Florence 1774. 8vo, In Swiflcrland, Sol.Schiiiz 

 jn Dc yl?re, ejus Spcc'i chits, frtrcipue dc Acre jixo hap'idi^ 

 ealcarei, Turic. 1778. 410.; and in Sweden, T. Bergmm lu 



* Statical f^fiTays pailim, 



N 4 Qe 



