﻿314 Transactions — Chemistry. 



evidence of the precise character of this absorption, and for this object I have 

 continued my investigations, and have varied their nature so as to secux'e 

 such evidence, quite independent of all that has been already advanced. 



It will perhaps be remembered that the whole of my evidence upon this 

 point, as at present given, is based upon certain chemical reactions which my 

 processes obtained. That which I now beg to lay before this Society rests uj)on 

 certain electrical reactions or manifestations which have discovered them- 

 selves to me; and, in anticipation of what should perhaps be left for disclosure 

 as a resultant of particular experiments, I will state now that these electrical 

 reactions are all extremely favourable, if not conclusive, as to the correctness 

 of the opinion which ascribes this absorption to chemical action. I may 

 observe here that this was the direction I contemplated taking for my experi- 

 ments at the time (one which they would indeed naturally have taken), but 

 that I had not the necessary apparatus to aid me in such a course. 



It is well known that the exercise of chemical force, or, as it is named 

 chemism, is always accompanied by a development of electricity, and this 

 varies in its intensity with that of the chemical forces brought into play. 



In cognisance of these facts, therefore, it occurred to me to test whether 

 electricity is developed at all during the sulphurizabion of either of these 

 metals. 



Taking two plates of gold prepared chemically pure, I placed one of them 

 in a cell charged with sea water, and the other in a porous cell charged with 

 sulphide of ammonium, which cell I partially immersed in the former. These 

 plates I connected voltaically at points quite clear of the liquid, and inserted 

 a delicate galvanometer in the circuit, when I found the needle of this instru- 

 ment was vigorously deflected over an arc of 20" to 30°, indicating, of course, 

 that a strong current of electricity was being generated. The direction of 

 this current, as shown by the needle, was from the inner to the outer cell. 

 The gold in the sulphide solution, therefore, was the positive element of the 

 pair. 



Electric currents of equal strength were also developed by charging both 

 cells with sea water, or with solution of potash or ammonia, and administering 

 sulphuretted hydrogen to the gold plate in either cell. The direction of these 

 currents was constantly from the cell to which the gas was applied. By 

 charging one of the cells with potash or ammonia, and the other with sea 

 water, a curi-ent of electricity was also produced, but this was of very 

 feeble intensity, and might well be owing to traces of sulphur in the alkaline 

 solutions . 



To avoid any errors which might be caused by films of air or other gases 

 adhering to the plates, and so getting in contact with the sulphide solutioiis, 

 these plates, prior to their immei'sion, were always raised to a r-ed heat, and 



