Page:Experimental researches in electricity.djvu/99

Rh of asbestus were lifted out, and the drops hanging at the ends allowed to fall each into its respective vessel. The acids in a and b were then first compared, for which purpose two evaporating dishes were balanced, and the acid from a put into one, and that from b into the other; but as one was a little heavier than the other, a small drop was transferred from the heavier to the lighter, and the two rendered equal in weight. Being neutralised by the addition of the soda solution (261), that from a, or the negative vessel, required 15 parts of the soda solution, and that from b, or the positive vessel, required 16.3 parts. That the sum of these is not 34 parts is principally due to the acid removed with the asbestus; but taking the mean of 15.65 parts, it would appear that a twenty-fourth part of the acid originally in the vessel a had passed, through the influence of the electric current, from a into b.

264. In comparing the difference of acid in A and B, the necessary equality of weight was considered as of no consequence, because the solution was at first neutral, and would not, therefore, affect the test liquids, and all the evolved acid would be in B, and the free alkali in A. The solution in A required 3.2 measures of the prepared acid (261) to neutralise it, and the solution in B required also 3.2 measures of the soda solution (261) to neutralise it. As the asbestus must have removed a little acid and alkali from the glasses, these quantities are by so much too small; and therefore it would appear that about a. tenth of the acid originally in the vessel A had been transferred into B during the continuance of the electric action.

265. In another similar experiment, whilst a thirty-fifth part of the acid passed from a to b in the free acid vessels, between a tenth and an eleventh passed from A to B in the combined acid vessels. Other experiments of the same kind gave similar results.

266. The variation of electro-chemical decomposition, the transfer of elements and their accumulation at the poles, according as the substance submitted to action consists of particles, opposed more or less in their chemical affinity, together with the consequent influence of the latter circumstances, are sufficiently obvious in these cases, where sulphuric acid is acted upon in the same quantity by the same electric current, but in one case opposed to the comparatively weak affinity of water for it, and in the other to the stronger one of soda. In the latter case the quantity transferred is from two and a half to three times what it is in the former; and it appears therefore