Additional Obfeyvatkns on Hydrocarbohateu 207 



water being added, the mercury rofe to 1.6, and lirae water abforbed the whole of the - 

 remainder, except .2 of a meafure which was inflanimable. 



In another experiment, no lefs than five meafure$ bf the bxigenated gas were mixed with 

 one of the hydrocarbonate, but (till at the end of the procefs there remained a very fmall 

 proportion of inflammable gas, and the whole of the oxigenated was not decompofed. In 

 thefe inftances, where We ufe but a fmall proportion of the hydrocarbonate, the explofioti 

 Is vbry feeble, and there is feldom or never any depofition of charcoal, in confequence of 

 which there is a more copious prpdudtion of carbonic acid gas, as may be readily feen by 

 comparing the experiments together.. Indeed in the laft one, the fame proportion of car- 

 bonic acid was obtained, as if the gas had been exploded or faturated with oxigen ; for one 

 meafure of pure hydrocarbonate requires very nearly two meafures of oxigen to f.iturate it 

 the produfts being water, and 1.3 or 1.4 meafures carbonic acid gas. Now in the expe- 

 riment with the oxigenated gas, one meafure of the hydrocarbonate fired with five of this 

 gas, produced juft 1.3 meafures carbonic acid, with water, &c. indeed fince five meafures 

 of the ox. muriatic acid gas contain an excefs of oxigen equivalent to two meafures, or a. 

 very little more, thisrefult ought to have been expe£ted. 



• There was nothing very remarkable obferved in exploding the impure hydrocarbonates- 

 with this gas ; all of them yielded carbonic acid gas and water, but in none of them did 

 I perceive any fenfible depofition of charcoal, except once from the gas obtained from the 

 decompofition of alcohol. Indeed the pure hydrocarbonates themfelves, in a great meafure, 

 lofe this property after having been waftied, or kept over water for fome time; that from 

 JEther retains it the longeft. Several attempts were made at different times to explode 

 mixtures of the ox. muriatic acid gas, and the gafeous oxide of carbon, but. without- 

 fuccefs. On pafling the fpark a little whitKh vapour was perceived round the metallic, 

 points, but this was not accompanied by any detonation, and even after a number 

 of ftrong fparks had been taken in this way, it was found on the admiflion of lime water,;' 

 which immediately took up the oxigenated gas, that the gafeous oxide had undergone no. 

 fenfible diminution or change. This circumftance was rather unexpe£ted ; it furniflies us,- . 

 however, with at leaft' one criterion for diftinguifliing this from other inflammable gafes. 



On comparing the above experiments with the refults obtained from firing the hydro- 

 carbonates with different proportions of oxigen, fome obfervations not unworthy of atten- 

 tion may be made. We know that when any -of the pure hydrocarbonates are fired with a 

 fmall proportion of oxigen, a little carbonic acid is produced, and the whole volume of. 

 gas inftead of being diminifhed is confiderably increafed ; this increafed gas contains no. 

 difengaged oxigen, but is neverthelefs very different from the original hydrocarbonate, re^ 

 quiring only bulk for bulk, about one fourth of the quantity of oxige;n to faturate it * ; no. 

 charcoal is ever difengaged. But when we expjode the fame hydrocarbonate with about 

 twice its bulk of the ox. m-uriatic acid gas, we have a great diminution, accompanied 



* It does not appear to be gafeous oxide, which I believe cannot be produced this wayi 



with 



