282 Chemical Instruments and Operations. 



When there is a copious supply of the gas to be examin- 

 ed, the barometer gage eudiometer may be used advan- 

 tageously, as much larger quantities of gas may be exploded 

 in it, than could be exploded in the same time, in the sliding 

 rod eudiometer.* 



In order to render the process with the barometer gage 

 eudiometer safe, the quantity introduced in the first instance 

 should be as small as can be ignited. Afterwards successive 

 portions may be introduced and exploded, until the receiver 

 be nearly full of the residual gas. That this operation may 

 be still more secure, I propose to employ, as a receiver, an 

 iron bottle (such as are used to hold mercury) surmounted 

 by a very stout glass tube, in which the platina wire may be 

 situated, which is to cause ignition. This tube would be 

 the only part of the apparatus which it would be desirable to 

 have transparent. Indeed transparency may be dispensed 

 with altogether, the explosion being perceptible from the 

 noise, and the effect upon the gage. 



D op 



And„ (M+O — C)+Y^ — will be that portion of oxygen which 



existed previously in the gas, which call X. 

 We have therefore the following equation : 



8M-f80 — 8C 8C 



which may be thus reduced : 



^ 88M + 880 — 88C + 72C 



O. 



99 



88M+88 — 16C 

 ~ 99 



_88 M + 88 — 16C— 990 

 ^— 99 



_88 M-16C-1 1Q 

 ^- 99 



It follows from the atomic weights, and the premises, that 



ov 3 Y 



— = the carbon in carbonic oxide. And X-j — ^=weight of car- 

 bonic oxide. 



SC 3 X 

 Also z r- ■= tlie carbon united to hydrogen. 



3C 3X , M-f O — C 

 And y. i -\ X = weight carburetted hydrogen. 



5ee this Journal, vol. xii. page 46. 



