Necessary to determine the specific gravities of the various gases referred to some one of them, say hydrogen; the numbers so obtained giving the weights of the molecules referred to that of the hydrogen molecule.
The following table gives the specific gravities of many metals.
Buchanan on the " Challenger " it has been usual for British investigators to calculate specific gravities for sea-water at 60° F.
Buchan, " Specific Gravities and Oceanic Circulation," Trans.
With all the important work he accomplished in physics - the enunciation of Boyle's law, the discovery of the part taken by air in the propagation of sound, and investigations on the expansive force of freezing water, on specific gravities and refractive powers, on crystals, on electricity, on colour, on hydrostatics, &c. - chemistry was his peculiar and favourite study.