experiences by the RJeHric Spark, 35 x 



^mpofed. The refiduums of gas after the operation are a 

 mixture of hydrogen gas, rclLihiiig from the decornpofiiioii 

 of the water, and carbonic acid gas deprived of water. 



Thisverv ingenious explanation" was without doubt the 

 only one which could prei'ent itfilf at the time when it was 

 given. Had it been juft, it would have Ijeen neceflary, by 

 rcitoring to the acid gas condcnfed by deficcation the water 

 it had loit, to dilate u again, and to augment about 13 inches 

 the column in queftiou. As C. Monge did not fubmit his 

 explanation to this decifive proof, I thought proper to at- 

 tempt it, 



I caufed to circulate for 18 hours eledric fparks in the 

 bulb of a matrafs which contained 13 cubic inches of pure 

 carbonic acid gas, and without any mixture of water fuper- 

 al)undant to that which it might naturally hold in folution. 

 The mercury, \x\ which the inverted matrafs was immerfed, 

 xjo^c to about the half of its neck. After eleftrifation, the 

 metallic fluid was found o.xidated black, as had been obferved 

 by Monge and Prieftley ; but my conductors, which were 

 of copper, were not fenfibly altered. The elaftic fluid liad 

 experienced a fmall dilatation, which appeared to me not to 

 exceed the tenth part of a cubic incli. I then made about 

 a grain of waterf to pafs in conla£l with the aeriform ga* 

 contained in the matrafs. I let it remain there for feveral 

 days, without perceiving any dilatation in the volume of the 

 gales, the refidua of the operation. 1 then moiflened, with & 

 <irc)p of water which I introduced, the whole infide of the 

 matrafs — but in vain — the mercury conftantly remained at 

 the fame hciglit. I however found, on ahfoibing by potafli 

 -the reliduum of live acid gas, that a cubic inch of carbonrc 

 acid gas had difappeared, and had been replaced by a quan- 

 tity nearly equal, or rather fuperior, to the inflammable gas. 

 The 20 cubic centimetres occupied in the neck of the ma- 

 trafs a column f )ur inches in length ; and the acid gas, had 

 the fuppofed explanation been jult, would have been dilated 



■' ft luppofcs that the carbonic acid gas may i.nhl in folution a great 

 quantity of water. But this aflenion is not pmved by any other din6t 

 experiment. Dr. Priellley wn$ not able to calcine carbonate of baryr« 

 but by the help of a current of aqueous vajKiur, wiiich he caufed to cir- 

 culate on that earth brought to a rtd heat. This refuJt may be explained 

 by the affinity alone of the water for the barytes. it is b> fuics poffibU 

 that the carbonic acid gas diifoivcs at a red 'heat a certain quantty ot 

 Witter, and dilate rnudi in th's folution, without producing thcic efftfCt* 

 at tlic temperature ot tiic atmolphcrc. 



+ It is needlefs to ohfcrvc here, tliat water can abfiarb no more f h«i it* 

 own vulomc of HCtd j^as wiiii the prcJTuro of the atmofjphcrc, ±ni that 

 tht drop of wattr introduced iuto the initrafw cojid not produce by, tlji 

 *Vfbrprion iny fetifiWc change in the^ohime of the eiiftic Huid. 



5 through 



