Skey. — Action of Potassium-Cyanide upo7i Gold. 715 



these to give us the potassium in a free state ? But sup- 

 posing even that he had aii electric battery laid on of sufficient 

 power theoretically to liberate potassium from its cyanide, 

 how^ can he expect even then to have potassium set free for 

 the minutest portion of time when there is water, also free 

 oxygen, in contact with the potassium compound during the 

 whole time that chemical action is going on ? No ; I con- 

 sider that in the experiments of all these investigators the 

 potassic cyanide or the potassic chloride is simply passed to 

 the oxide by a substitution so direct that never was any of the 

 metal set free. A person travelling over the boundary of two 

 Shires has never any part of his person clear of both ; so 

 here the atom of potassium in exchanging companions is never 

 clear — that is, never free in any part of it of one or the other. 

 This is the position I have long taken on the subject generally, 

 and I cannot retire from it before I have something more than 

 mere assertions, whatever direction they come from. 



I would like to make here a few observations in connection 

 with Mr. Maelaurin's important discovery of the great inso- 

 lubility of oxygen in strong solutions of potassic cyanide. In 

 the Laboratory Notes of mine already referred to I state, in 

 affirmation No. 2, " That, generally, any salt added to a good 

 working solution of the cyanide acts the same as an equal 

 quantity of the cyanide in retarding or preventing dissolution 

 of gold."''- Now, these facts lead me to suppose that it is a 

 general law that all aqueous solutions of salts, fixed alkalies, 

 and alkaline earths are also solvent of oxygen in a proportion 

 inversely to that of their strength ; that, in fact, Mr. Mae- 

 laurin's law for the cyanide solution is really a general law 

 for all saline solutions. This receives some support from the 

 fact that a great number of solid salts, when dissolved in 

 ordinary water at a common temperature, liberate gas, while 

 if the water has been boiled for a considerable time, then 

 rapidly cooled, and then immediately placed over any of these 

 salts, not a trace of gas can be seen to escape therefrom as 

 the salt dissolves. I formerly considered that the gas escaping 

 when crystallized salts were placed in water was simply the 

 air they had occluded in the act of crystallization ; but it 

 appears pretty clear- to me now that this was one of my mis- 

 conceptions. 



In the light that our recent discoveries throw on the exact 

 chemical nature and reactions involved in the cyanide process, 

 I now venture to state here my opinion on the question as to 

 whether in that process as conducted at the mines the gold is 

 first oxidized or cyanodized ; and it is this : In a plentiful 



* The fixed alkalies act similarly, but not ammonia or chloride of 

 ammonium. 



