Page:The fundamental laws of electrolytic conduction.djvu/66

 cations after the decomposition than before. The other side shows the converse relation.

This result evidently holds generally. If one ion moves through the distance, and the other, then the side of the liquid in which the former appears will contain equivalent more of it and equivalent less of the other ion. The converse relation will hold for the other side of the electrolyte.

Fig. 3

The first experiments to determine the transference of ions quantitively, were made by Faraday. He took up the subject, however, only as a side issue, and confined himself to two electrolytes, dilute sulphuric acid, and a solution of sodium sulphate. Two pairs of cups were filled respectively with definite amounts of these two liquids, and each pair connected together by means of asbestos. Both were then introduced into the same circuit, and after electrolysis had continued for some time, the asbestos was withdrawn, and the contents of the cups subjected to analysis. It is clear that this method is very defective, and that no accurate results are to be expected with it. The results which Faraday obtained in two series of experiments show this sufficiently. In the case of the sodium salt, he determined only the sulphuric acid set free, and tacitly assumed that half of it had been transferred.