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arrangement may properly be termed a pyritous battery — in accordance with 

 tlie custom hitherto observed, of designating new forms of batteries after some 

 distinguishing or novel feature in them. 



Several other metallic sulphides manifest similar phenomena when coupled 

 in this manner with zinc, amongst which are the following : — zinc blende, 

 copper pyrites, vitreous copper stibnite, pi^oto-sulphide of iron, and the sulphides 

 of silver, mercury, platinum, and gold. 



The only sulphide I have yet found any difficulty with in setting up this 

 action, under these conditions with zinc, is mundic, or the bi-sulphide of iron ; 

 but if the point of contact between it and the zinc is submerged in the acid, 

 gas is evolved at this point, and the area of evolution rapidly spreads around 

 from this, until the whole surface of the specimen becomes active. 



The gas given off from the surfaces of these sulphides in the foregoing 

 experiments, was sulphuretted hydrogen. The effects, therefore, upon these 

 sulphides when thus made to form the negative pole of a galvanic pair, is to 

 desulphurize them ; in some cases the ultimate effect is to reduce the metal to 

 the metallic state. At any rate this obtains for the sulphides of mercury, 

 lead, silver, platinum, and gold. "With common yellow copper pyrites, a 

 beautiful iridescence is communicated to it in a few seconds after the liberation 

 of gas commences, owing, of course, to desulphurization. 



Saline solutions appear to produce the same effects in these instances as 

 sulphuric acid, but they take place much slower. 



The fact is thus directly established, that several of the metallic sulphides 

 are capable of performing all the functions of the negative pole of a galvanic 

 pair. From this, and the manner in which these sulphides have been 

 connected with each other, it is clearly demonstrated that they are pretty good 

 conductors of electricity. To a certain extent, indeed, all bodies are conductors 

 of electricity, the terms conductor and non-conductor being only expressive, as 

 Faraday affirms, " of exti'eme degrees of one common condition," there being 

 no complete conductor, nor any absolute non-conductor ; but these results 

 show, I think, these sulphides are conductoi'S to a degree not before recognized 

 — a circumstance which renders a comparison of their conducting power with 

 that of other conductors necessary. 



Indirectly it has appeared, that nascent hydrogen is able to decompose these 

 sulphides at common temperatures, by combining directly with their sulphur, 

 thus accomplishing at a low temperature that which would requii-e a very high 

 one, in case it (the hydrogen) were presented to the sulphide in its ordinary 

 form. 



In relation to the amalgamating processes used for the extraction of gold 

 at our batteries, these results prove that zinc amalgam, in contact with acid 

 solution, has precisely the same effect in decomposing the sulphides of gold, 

 mercury, iron, etc., as sodium amalgam ; like this amalgam, therefoi'e, it keeps 



