Page:Experimental researches in chemistry and.djvu/176

1825.] vapour over heated oxide of copper:—0.776 grain of the substance produced 5.6 cubic inches of carbonic acid gas, at a temperature of 60°, and pressure 29.98 inches; and 0.58 grain of water was collected. The 5°6 cubic inches of gas are equivalent to 0.711704 grain of carbon by calculation, and the 0.58 grain of water to 0.064444 of hydrogen.

These quantities nearly equal in weight the weight of the substance used; and making the hydrogen 1, the carbon is not far removed from 12, or two proportionals.

Four other experiments gave results all approximating to the above. The mean result was I hydrogen, 11.576 carbon.

Now considering that the substance must, according to the manner in which it was prepared, still retain a portion of the body boiling at 186°, but remaining fluid at 0°, and which substance I find, as will be seen hereafter, to contain less carbon than the crystalline compound (only about 8.25 to 1 of hydrogen), it may be admitted, I think, that the constant though small deficit of carbon found in the experiments is due to the portion so retained; and that the crystalline compound would, if pure, yield 12 of carbon for each 1 of hydrogen, or two proportionals of the former element and one of the latter.

This result is confirmed by such data as I have been able to obtain by detonating the vapour of the substance with oxygen. Thus in one experiment 8092 mercury grain measures of oxygen at 62° had such quantity of the substance introduced into it as would entirely rise in vapour; the volume increased to 8505: hence the vapour amounted to 413 parts, or $1⁄206$, of the mixture nearly. Seven volumes of this mixture were detonated in a audiometer tube by an electric spark, and were diminished in consequence nearly to 6:1: these, acted upon by potash, were further diminished to 4, which were pure oxygen. Hence 3 volumes of mixture had been detonated, of which nearly 0.34 was vapour of the substance, and 2°65 oxygen. The carbonic acid amounted to 2.1 volumes, and must have consumed an equal bulk of oxygen gas; so that 0°55 remain