Polytechnic Association Proceedings. 935 



nator understauds what he is about. This process is also adapted 

 for the treatment of silver ores. 



Dr. Hagan's desulphurizing process with hydrogen gas and car- 

 bonic oxide and acid, produced by previous decomposition of 

 steam by carbon, is, as I learn, worked quite successfully for two 

 years past in both Grasse Valley, Nevada Co., California, and Ply- 

 mouth Ledge, in the same State. The Eureka or Eyason process 

 is also said to work well in the Mariposa State in California. In 

 this process, I learn, the disintegration, desulphurization, and 

 extraction of gold by amalgam are all produced by the action of 

 heated steam and mercuiy vapor on the ore while in a closed vessel, 

 and the tailings run over a peculiarly constructed shacking table, 

 so as to concentrate all the amalgam. 



We will now pass finally to another system, the smelting method. 

 When a rich gold ore is heated in a reverberatory or other furnace, 

 and an appropriate material as flux added, the ore melts with it t» 

 a liquid mass, in which the specifically heavy gold will collect, melt 

 and sink to the bottom. Soda, lime, oxides of iron have been 

 extensively used, and some to great advantage. By my experiments 

 with the so-called Stevens flux, the residuum from the cryolite when 

 worked for soda, I have been brought to the new idea that gold 

 must exist in nature as a silicate of the oxide of gold chemically 

 combined, for, by treating the same ore with other agents (fluxes 

 that do not fully decompose silica), I could not obtain the same 

 results. 



This Stevens flux is superior to the natural fluorspar, because it 

 contains free oxfluorine gas, which has been absorbed by lime in a 

 similar way as chlorine is taken up by it in the bleaching powder, 

 hence its greater efficiency. 



The fluorine has such affinity for the silica that it leaves the 

 calcium, drives oft' the oxygen, and combines with the silicium to 

 form fluor silicium and fluosilicic acid. The calcium takes up the 

 oxygen and forms lime. 



I have lately seen some astonishing results produced by the use 

 of this flux with Nova Scotia and Georgian ores. 



Mr. H. G. Hubert, of this city, has recently patented a system 

 of furnaces, in which he uses a mixture of flux and ore as continu- 

 ous lining of the furnaces (either cupola or reverberatory) with an 

 impervious carbon bottom. This system cannot fail to come into 

 use when this peculiar method of smelting shall have been better 

 known and appreciated. 



