Chap. 5.3 Inflammable ATT, *y$ 



which may be again expelled by heat, and will then 

 be equally inflammable as before. 6thly. Hydrogen 

 gas, cr inflammable 'air, is fatal to animal life; in 

 proof of which Mr. Cavallo relates, that the Abbe 

 Fontana, having filled in his prefence a large bladder 

 with inflammable air, began to breathe it, after having 

 fnade a, violent expiration. The firft infpiration pro- 

 duced a painful oppreffion on his lungs ; the fecond 

 caufed him to look pale ; and the third was fcarcely 

 accomplifhed, when he fell on his knees through 

 weaknefs. Small animals are alfo killed by a very 

 few infpirations of this noxious fluid. 7thly. This 

 gas is faid to have a fmaller fhare of refractive power 

 than common air. 



It is on account of its lightnefs that hydrogen gas 

 has been moft frequently employed in aeroftation. 

 The method of filling a balloon is only enkrging 

 the procefs which has been defcribed for producing 

 inflammable air on a fmall fcale. 



Very pleafing fireworks may be made from this 

 gas, by filling bladders with it, and fixing brafs 

 cocks to them, by means of which the gas may be 

 difperfed into any number of glafs tubes bent in va- 

 rious fhapes, and with fmall . holes in various parts 

 of them ; then by preffing the bladders more or lefs, 

 as occafion may require, the gas will pafs into the 

 tubes, and ifTue out of the fmall holes, to which a 

 lighted taper may be applied; by thefe means the 

 air will take fire, and will continue to burn until the 

 courfe of it is Hopped by Ihutting the cock at the 

 neck of the bladder. Thefe aerial fireworks may be 

 made to reprefent different figures, either movable 

 or immovable, and may be ornamented with different 

 colours. The white coloured flame is produced by 

 hydrogen gas procured from common coal; again, 



by 



