206 On the Composition arid Analysis 



of hydrogen and 3 of olefiant, upon the presumption that 100 

 cubical inches of hydrogen weiglj 2,25 grains, and 100 ot olefiant 

 30,15. 



Such a niixture, wlien submitted to the action of heat, of 

 sulphur, and of chlorine, and when detonated with oxvgen, 

 afforded results .similar to tho?e obtained by eNperiments I'.pon 

 the original oil gas, and it burned with the banie degree of bril- 

 liancy. 



9. I have also submitted to similar experiments the inflam- 

 mable gases obtained by the decomposition of acetate of potash, 

 of alcohol, and ether, and by passing water over rod hot char- 

 coal. All these contain a considerable portion of carbonic acid, 

 which, when abstracted by potassa, leaves a mixture of car'nu- 

 retted hydrogen, hydrogen, and carbonic oxide, in proportions 

 liable to much variation, according to the materials employed, 

 rnd to the circumstances under which their decomposition has 

 been effected. Tiie specific gravity of these products is of course 

 liable to corresponding variations. 



10. The inference which, I think, may be drawn from the 

 preceding experiments and observations, is, that there exists no 

 definite compound of carbon and hydrogen, except that usually 

 called olefiant gas; that the various inflammable compounds 

 employed for the purpose of illumination, and produced by the 

 destructive distillation of coal, oil, &c. consist essentially of a 

 mixture of olefiant gas and hydrogen ; that the gas procured from 

 acetate of potash and from moist charcoal contains the same ele- 

 ments, with carbonic oxide and carbonic acid; and that no other 

 definite compound of carbon and hydrogen can be recognised in 

 them, except olefiant gas. 



Section II. 

 Comparative experiments on the illuminatingand heating powers 

 of olejiant, coal, and oil gases, and on some general proper- 

 ties of radiant matter. 



1. In the following experiments I employed a gasometer with 

 counterpoise ivtights acting over regulating pnllics, and capable 

 of containing about 5000 cubical inches, or about 2,S9 cubical 

 feet: the different jets were attached to it in the usual way, and 

 the pressure was measured by the difference in the level of the 

 water within and without the bell, to which was attached an ac- 

 curately graduated scale sliding through the frame of support. 



2, Having filled this gasometer with pure olefiant gas, it was 

 allowed to issue from a brass jet having a single perforation of 

 g'j^ of an inch diameter, under a pressure of a half inch column of 

 water ; it was then inflamed, and regulated by means of a stop- 

 cock, so as to produce a light equal to that of a wax candle 

 burning with full brilliancy; tlie relative intensity of the light of 



these 



