47 



Art. XV. — On Chlorine as a Solvent of Gold, By the 

 Rev. John J. Bleasdale, D.D. 



[Read 21th May, 1862.] 



Chlorine is here considered as a substitute for mercury, 

 both on account of its comparative cheapness, the smaller 

 quantity of water needed, and its capability of dissolving out 

 a quantity of gold to which the mercury, for reasons to be 

 given, cannot attain. 



These disadvantages of the mercury process, are : 1st. 

 Repulsion between the fine particles of quartz and mercury ; 

 and 2nd, the necessity of keeping the quartz, mercury, and 

 water in a state of constant agitation, in order that the 

 mercury may have a chance of coming in contact with the 

 gold. 



Now, though the contrivances already devised for effecting 

 these purposes are very good, and seem to have reached the 

 limits of human ingenuity, as anyone may see who will pay 

 a visit to the Mining Museum at the University, yet they 

 are very far from being able to remove the whole of the gold. 

 It has been thought that forty per cent, of the finer gold is 

 lost in the mercury process. I cannot state from personal obser- 

 vation, but even supposing only twenty percent, to be lost, the 

 loss is enormous. I speak of twenty per cent, that was in 

 existence in the quartz when put into the mill to be crushed. 

 The currents of water and the various beautiful contrivances 

 for bringing the mercury and gold into contact, keep a large 

 quantity of the finely crushed gold afloat, and consequently 

 float it away. There is, moreover, a deal of gold in a state 

 of extremely fine division in the matrix, almost invisible to 

 the unaided eye, but evident when put under a microscope 

 of but low power. Experiments performed upon samples of 

 rock containing gold in this state, from Steiglitz, Ballaarat, 

 and the Ovens, were several times repeated by my 

 friend the late Count John Dembinski and myself. Our 

 experiments were necessarily on a small scale, but yet suffi- 

 cient to yield pretty reliable results of a comparative kind. 

 For example, equal weights of the same specimens were 

 roasted, crushed, and amalgamated carefully, and the corre- 

 sponding halves roasted, crushed, and treated with chlorine, 

 in the manner which I shall describe by-and-by. The mean 

 of four experiments showed an increase by the chlorine pro- 

 cess of nearly thirty-eight per cent, over the mercury. 



