84 Mr. Davy on a new Gaseous Compound of Carbon and Hydrogen. 



carbon, and inflammable air* remained. I made many experiments to determine 

 tbe exact composition of the new gas, using different methods ; as firing it with 

 oxygen or nitrous gas, or employing electricity alone ; but the most satisfactory 

 results I have obtained, were, by detonating a mixture of it with rather more than 

 four, and five times its volume of pure oxygen, over dry mercury. This expe- 

 riment, requires to be made with very limited quantities of the new gas, from the 

 violence of the explosion. The necessity of operating on small portions of the 

 gas, was a fortunate circumstance ; as I have rarely had at my disposal, at any one 

 time, more than a single cubic inch of it ; and in general, a quantity scarcely 

 exceeding the one-fifth of that volume. In one experiment, in which I fired a 

 mixture of five measuresf of the new gas, with twelve of oxygen, the residual 

 gas burned with a pale blue flame, showing that the oxygen was not in sufficient 

 quantity for the consumption of that gas. In a number of other experiments, I 

 used the oxygen in larger proportion, but I did not obtain uniform results ; 

 owing, I conceive, to the impurity of the new gas, arising chiefly from admixture 

 with a little hydrogen, occasionally liberated from minute portions of potassium, 

 diffused through the black substance. In a few cases, the results agreed so 

 exactly, that I shall venture to deduce the composition of the new gas, chiefly, 

 from two experiments. 



First Experiment. 



4 measures of new gas, mixed with 

 17 „ of oxygen, diminished by electricity to 



15 „ and by agitation in a solution of potash, to 

 7 j> which were oxygen. 



Second Experiment. 

 3 measures of new gas, mixed with 



16 „ of oxygen, diminished by electricity to 

 14^ „ and by agitation in limewater, to 



8^ 5, which were oxygen. 



* Since this paper was read, I have ascertained, that the " inflammable air," here spoken of, is in 

 fact, another new compound of carbon and hydrogen. A brief account of it was read at the last 

 meeting of the " British Association for the Advancement of Science," held at Liverpool in 1837. 



■f The measures, here and subsequently noticed, were, each of thein, equivalent to about seventy- 

 three grains of mercury. 



