﻿Skey. — Electro-motive Poiver of Gold and Platina in Sulphides. 315 



plunged while in this state into water or the solution about to be used, which 

 liquids, moreover, had been previously boiled for many hours to expel the 

 gases dissolved in them. 



The same kind of electrical reactions were obtained by substituting platina 

 for gold in these experiments. 



It was further found that gold paired with platina in sulphide solutions 

 is negative to it, but if paired with iron it is positive. It is necessarv in order 

 to obtain this latter result to use sulphide solutions quite clear from free 

 alkalies, otherwise their electric order is reversed. For this purpose it is 

 best to prepare such solutions by boiling the carbonate of the alkali with 

 sulphur for some hours. 



As appropriate to the subject, I will insert here a table of the electro- 

 motive order of the several metals I have tested in sulphide of sodium. The 

 order observed is from negative to positive : — 



Carbon Mercury 



Iron Lead 



Steel Tin 



Gold Copper 



Platinum Zinc 



Silver 

 The currents thus developed by gold and platinum in sulphide solutions 

 soon ceased, but they were so well marked, and had such an apparent intensity, 

 that I was induced to try if they had any effect upon certain metallic sokitions, 

 and on trial I found that, in the case of that obtained by the use of gold plates in 

 contiguous solutions of potash and sulphide of potassium, a degree of intensity 

 was reached sufficient to decompose solutions of copper, silver, and gold, and 

 to deposit these several metals in adherent films upon proper electrodes. The 

 same results were afterwards obtained with platinum. 



This capability of gold and platinum to generate electrical currents under 

 these circumstances — currents of such intensity as to exhibit true electro- 

 lytic effects — when taken along with the results of my former experiments 

 on this subject, appears conclusive evidence in favour of the sulphurization of 

 these metals being, as has been already argued, the result of chemical action. 

 It is very difficult to suppose that the mere absorption or condensation of 

 sulphur from these various solutions by gold or platinum could ever produce 

 electric currents having so great an intensity, since the sulphur, being in a 

 liquid form, must already be condensed almost to a maximum. 



I must apologise if I have appeared to dwell too long upon the subject of 

 the nature of this absorption, but the exceedingly close structure of the metals 

 experimented with, and their very high atomic equivalents, restrict this absorp- 

 tion to one of the most superficial character, and thus preclude us from 



