794 0'* t^^ different G.^fes. 



bratcd Grotto ilcl Cane, near Naples *, as well as with tf)? 

 exhalations in mines, againR the pernicious efte6ts of whicU 

 cautions had been given long before his time by Andrew 

 Libavius f and George Agricola X ; and he knew alfo that 

 they killed animals which had purpofely or accidentally been 

 «xpofed to them, as well as imprudent perfona, and particu- 

 larly miners. He was in particular acquainted with that ga» 

 which fomc, becaufe it inflames when it comes in conta6fc 

 with a burning body, call inflammable gas, and which others, 

 becaufe they confider it as an eflential component part of 

 water, name hydrogen gas j and he knew alfb that it had 

 been obferved before hrm in mines by Lrbavius : he con- 

 vinced himfelf that even eru61ations were of the fame na- 

 ture, and that it formed a principal component part of 

 Imoke : he Irkcwife confidered flame to be only inflamed 

 fmoke§. His knowledge, however, was not confined to this 

 gas alone, for under the name of gas fjlvejlre he w^as ac- 

 quainted with «itrous gas, produced by the action of aqua- 

 fortis when filver is diflblved in it || ; and he knew alfo, that 

 when it came in contaft with the atmofphere it formed fiery 

 red vapours. 



He was well acquainted alfo with the muriatie acid gas ; 

 for what elfe could he underftand by that gas into which, to 

 ufc his own expreffionsf, fal-ammoniac and aquafortis were 

 converted w hen mixed together and made luke-warm ? He 

 knew likewife the fulphurous acid gas ; for he fought in it, 

 as a component part of the vapour of burning fulphur, tloe 

 reafon why that vapour extingurfhcs a lighted candle or taper 

 when expofed to it. 



He had become acquainted alfo, different ways, with that 

 gas which lliows itfelf in air in whii:li varimis bodies, and 

 particularly coals, have beenburat**; and on that account 

 he had given it the name of coal gasj though he had feen 

 abundance of it in various places, and accompanynig other 

 pha?nomena, both in living human bodies, as for example in. 

 bclchinsjtt; and on a larger fcale, as in wine and beer cel- 

 lars, and during the eflervefcence of diflerent fubltanccs whea 

 acids were poured upon them J+, in tlie Grotto del Cane and 



^ Ortus Medicinx, p. iio. 163.611:. 



f Comiviintat. IVktallic. Francof. ad Man- 1597. 4to. p. 297. 



+ Dt Natuia torum qua; tffluunc ex terra. 



§ Conimeiirat. MctaUic. ut fupra, p. 42 1. 414. 84. 



jj Dc A<iiii-> Stygiis, ui fupra, p. 615. 424. 



•I Ortns Mcdicin,E, p. 4*3. 



•-' Ibitl. p. 110. 106. no. 405,406 — 437: Tumulus pcftis, p. 55, 



•ft fb'd. p. 116. 42r. 431. 



X\ Ibid. p. 424; and Dc FcbrJbus, c. Ji. p. 43. 



'5 o.tlip' 



