The Action of Silica on Electrolytes

Abstract

FROM Dr. Joseph's letter in NATURE of March 28, p. 460, it appears that our differences are mainly with regard to observation of facts. I therefore describe below the method of preparation of the hydrated silica used in most of our experiments: it was obtained from the hydrolysis of twice-distilled pure silicon tetrachloride. The silicon tetrachloride in the final distillation was collected in a transparent fused silica flask. The liquid was hydrolysed in the same vessel, and in the subsequent treatment only fused silica vessels were used. The silica was dried in air at room temperature in a place free from fumes. If Dr. Joseph finds difficulty in preparing the samples, I shall be glad to send him a sufficient quantity for his experiments. I would, however, point out that the silica used by Dr. Joseph differs from ours in one respect in that the silica was heated to 180°. We have found that, on ignition, the adsorptive capacity of hydrated silica diminished markedly, and probably the failure of Dr. Joseph to confirm our results is to be attributed to his having used samples which were “finally dried and heated to 180°”.