Gn the different Gafei. 1 95 



Other fubtcrranean places*; and particularlY In acid waters, 

 from which it riles in bubbles, and they are indebted to it, he 

 fays, for all their healing qualities \. He remarks alfo of this 

 gas X, that, as it extinguiflies the flame of a lamp or taper, it 

 extinguillics alfo the flame of life. He proved, by a very 

 fimple experiment §, that the volume as well as the goodnefs 

 of air is leifened bv bodies burning in it; for, having placed 

 a burning taper under a glafs in iuch a manner that it flood 

 three inches above the water in the vefll'l, he faw the water 

 rife, afl'unie the place of the decreafing air, and at length 

 extinguifh the taper. 



He had obfervcd alfo that an air could be produced from 

 nitre, which he called ^t/;«^' gas, and which was difen- 

 gaged on coal being added to it j| ; and he thence conjeftured 

 the prefence of vital air in that fait. He entertained alio the 

 opinion, which modern chemiltry has fupporte.d by fo many 

 concluflve proofs, that all thefe air-like fluids 1[ arc indebted 

 for their form to the efte(3^s of fire, or, as we commonly fay 

 at prefent, to caloric. 



It cannot, however, be denied, that Van Helmont confi- 

 dered as diflerent gafes thofe which dificr onlv by accidental 

 corruption, as the carbonic acid gas, according as it is drawrj 

 from this or that body, and in this or that manner; and that 

 he confounded others, or did not make a proper diftinetiou 

 between them. Yet before Pricftley, moft of the philofo- 

 phcrs who paid attention to this fubjeft, made no other dif- 

 ference between ihcfe kinds of gas, than that fome of them 

 inflame when brought into conta6l with a burning body, 

 while others inftantlv cxtinguifh a flame. 



Van Helmont furi)et^led alfo, as appears clearly from his 

 own words, the great fimilarity which, in regard to air, is 

 found between flame and animal life. This was more clearly 

 perceived by Thonias Willis '^* and Francis Sylvius de le 

 Boii ft, a man whom few have equalled in genius or elo- 

 ijuence ; for the latter fays, that, as flame requires more air 

 than tile qnittly glowing fire of coal, in the like manner 



• Ornis IVIc(liciiia». 



f Dc l.itliiafi, c. iv. p. 54. 



X Ortus Mcdiciir*, p. 1O3. 



§ Ibid. p. 84. 



•I Ibid. p. 72. 



" * Atfcctionum f)'.!;!' difuntiir hyftcrlcs et hyporhondli^c.^' Pafliologia 

 fpifmodici, contiu Rciponiioniin cpiltiilarciii Nutli Hivjhmoi', rui accLll'i;- 

 nint llxurciiationct mcdico-phyfice du*, (kc. ; Lugd. Bat. 1071. umo. 

 f. ^o — lOt. 



4 I Dilputat. de Rtrpiratioae, ^y ^9— --j. 



N a breathing 



