196 Mr. Faraday on nem Compounds of Carbon, S^c. 



3-2 

 3-4 



15-7 

 23-4 

 16-1 



7-4 



3-7 



1-3 



Tlie residue, 3*4 parts, was dissipated before 250° witii slight 

 decomposition. The third column expresses the quantity 

 volatilized between each 10°, and indicates the existence of 

 what has been described as bi-carburet of hydrogen in consi- 

 derable quantity. 



The importance of these vapours in oil gas, as contributing 

 to its very high illuminating powers, will be appreciated, when 

 it is considei'ed that with many of them, and those of the denser 

 kind, it is quite saturated. On distilling a portion of liquid, 

 which had condensed in the pipes leading to an oil gas gaso- 

 meter, and given to me by Mr. Hennel, of the Apothecaries' 

 Hall, I found it to contain portions of the bi-carburet of hy- 

 drogen. It was detected by submitting the small quantity of 

 liquid which distilled over before 190° to a cold of 0°, when 

 the substance crystallized from the solution. It is evident 

 therefoi'e, that the gas from which it was deposited must have 

 been saturated with it. On distilling a portion of recent coal 

 gas tar, — as was expected, none could be detected in it ; but the 

 action of suljihuric acid is sufficient to show the existence of 

 some of these bodies in the coal gas itself. 



With respect to the probable uses of the fluid from com- 

 pressed oil gas, it is evident in the first place, that being thus 

 volatile, it will, if introduced into gas which burns with a pale 

 flame, give such quantity of vapour as to make it brightly il- 

 luminating; and even the vapour of those portions which re- 

 quire temperatures of 1 70°, 1 80°, or higher, for their ebullition, 

 is so dense as to be fully saflicient for this purpose in small 

 quantities. A taper was burnt out in a jar of common air 

 over water; a portion of fluid boiling at 190° was thrown up 

 into it, and agitated : the mixture then burnt from a large 

 aperture with the bright flame and appearance of oil gas, 

 though of course many times the quantity that would have 

 been required of oil gas for the same light was consumed ; at 

 the same time there was no mixture of blueness with the flame, 

 whether it werelijrge or small. Mr. Gordon has, I understand, 

 proposed using it in this manner. 



The 



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