Note 41 — Chapter VIII · CARBON AND THE HYDROCARBONS

Acetylene and its polymerides have an empirical composition CH, ethylene and its homologues (and polymerides) CH2, ethane CH3, methane CH4. This series presents a good example of the law of multiple proportions, but such diverse proportions are met with between the number of atoms of the carbon and hydrogen in the hydrocarbons already known that the accuracy of Dalton's law might be doubted. Thus the substances C30H62 and C30H60 differ so slightly in their composition by weight as to be within the limits of experimental error, but their reactions and properties are so distinct that they can be distinguished beyond a doubt. Without Dalton's law chemistry could not have been brought to its present condition, but it cannot alone express all those gradations which are quite clearly understood and predicted by the law of Avogadro-Gerhardt.