]74 COMBUSTION OF CHARCOAL AND OP HlDROCtEN. 



sent* in these two substances. It .may act an important 

 part however in vegetation^ and in a great number of other 

 processes. 

 On the con- When hidrogen gas is burned slowly, .rapidly, or insjtan- 

 d^nsatiun of taneously in a mixture of oxigen and nitrogen, the last 

 VoltJs eudio- mentioned gas is in part condensed; combining, according 

 mcur. to the proportions of the mixture, either -with the pprigen 



alone, or witlj the, oxigen and hidrogen.* These effects are 

 sufficiently great in some circumstances, to occasion consi- 

 derable errqurs in eudiometrical experiments by Volta's 

 process. r fh\& will appear from the following, instances, 

 winch have been repeated a great many times. ,- 



Two hundred parts of, hidrogen gas -procured by means 

 of zinc, and ^00 parts of oxigen, in which fche-hiilrosyl- 

 phuret of potash indicated 5;75 of nitrogen, left, after their 

 .gletonation and the action of potash, a residuum equal, £o 

 1£2'5 parts. This result indicates. at leasj l*7rpf ni.rogen 

 in the 200 of hidrogen*. 



Two hundred parts of the same oxigen gas, and 200 of 

 the same hidrogen, were burned with 200 parts of nitrogen 

 • * . extracted from. common air. The .residuum of the. deto- 

 * nation, after the action of the potash, was only 197*5 p^rjts; 

 but according to the preceding experiment \\ ought to have 

 been 202*5, if the nitrogen addedJiad not sensibly affected 

 the result. m 4 



To judge of the quantity of nitrogen condensed* I tr^aj- 

 ed these 107*5 parts wjjh potash, and wih ( hidrosulphuj;et, 

 by which they were reduced to 105*45. Now the q.uajntity 

 of nitrogen introduced in this experynent^was \00 t \- 5*75 4- 

 J*7 =: 107*45. The combustion therefore condensed 107*45 

 — 105*45 ~ 2 J>arts of nitrogen. This result was the mean 

 of a great number of observations. 



In the preceding experiment, where 300 parts of hidro- 

 gen, containing 1*7 of nitrogen, were burned with 200 of 

 oxigen, in which 5*75 of nitrogen were included, the latter 



• I admit, with Gay-Lussac, that 200 paits of hidrogen condense 100 

 of oxigen. But 1 must observe, th*at the formation of carbonic acid gas, 

 which accompanies the combustion of the purest hidrogen, may modify 

 this assertion in a very slight degree, or prevent it fr >m being prowed'to 

 less than a thousandth part of the voinmerof fthe bi&og'en,, , + 



was 



