On Gold Refining ly Chlorine Gas. 167 



"as in the refinage by the ordinary sulphuric acid process the 

 same result cau be obtained by subjecting the refined gold to a 

 further refinage with bisulphate of potash. For practical work- 

 ing, however, this would probably never be attempted. 



The silver resulting from this method of refining is tough, but 

 its quality varies somewhat according to the gold originally 

 operated on : if the alloy treated contains much copper the 

 greater part of this remains with the resulting silver, but the 

 other metals are nearly all eliminated. 



The fineness of the silver hitherto obtained has varied from 

 9182 to 9920 in 1000 parts, the average being 9655. 



Analysis of the silver resulting from the refinage of gold known 

 originally to have contained amongst the base metals in the 

 alloy ccpper, lead, antimony, arsenic, and iron, gave the 

 following results : — 



Silver 972-3 



Copper 25-0 



Gold ... 27 



Zinc and iron... ... ... ... Traces 



1000-0 

 A very extended series of experiments have been made at the 

 Sydney Branch of the Royal Mint to test the value of this pro- 

 cess, and the result has been (as mentioned by the Hon. the 

 Colonial Treasurer, in his speech on the Budget, October 14, 

 1860) that " active steps are now being taken to bring the 

 system into operation " in that establishment. 



I have already, in the paper read before the Chemical Society, 

 acknowledged the obligation I feel under to my brother officers 

 — Mr. Robert Hunt and Dr. Leibius — for their kind help and 

 encouragement in perfecting this process of refining : but my 

 especial thanks are also due to Professor Smith of the Sydney 

 University, who, in the kindest manner, placed his laboratory at 

 my disposal to assist me in this matter, and also to Dr. Thomson 

 and Mr. Edward Hill for their valuable and friendly help. 



