X. Notes of researches on the polyammonias.—No. IX. Remarks on anomalous vapour-densities

In a note addressed to the Royal Society at the commencement of this year, I have shown that the molecules of the diamines, like those of all other well-examined compounds, correspond to two volumes of vapour, and I have endeavoured to explain the apparent anomalous vapour-densities of the hydrated diamines by assuming that the vapour-volume experimentally obtained was a mixture of the vapour of the anhydrous base and of the vapour of water. Thus, hydrated ethylene-diamine was assumed to split under the influence of heat into anhydrous ethylene-diamine (2 vols. of vapour) and water (2 vols. of vapour). C2 H10 N2 O = (C2 H4 )"} H2 } H } H2 }N2 + H } O. The vapour-density of ethylene-diamine referred to hydrogen being 30, and that of water vapour 9, the vapour-density of a mixture of equal volumes of ethylene-diamine and water-vapour = 30 + 9/2 = 19·5, which closely agrees with the result of experiment.