122 PROCEEDINGS OF SECTION B. 



Minerals of New South Wales," under the heading of " Native 

 Tellurium '\: states — "a rare element; reported to occur at Bingera, 

 CO. Murchison." 



I have examined several samples of bismuth ore from various 

 parts of the colony, and in one or two cases, notably, in one 

 sample obtained from the Kingsgate Mine, near Glen Innes, a 

 strong trace of tellurium was found. 



This ore consisted of sulphide of bismuth with molybdenite and 

 metallic bismuth, it also contained a few ounces of silver to the ton. 



3.— NOTES ON SILVER SMELTING. 



By EdCxAr Hall, F.C.S. 



Note 1. — on the separation of silver in smelting rich ores 



so as to obtain slags free from silver. 



In the extraction of silver from ores by smelting, whether 

 the precious metal be obtained in alloy with metallic lead, 

 as in reducing lead ores, or concentrated into a regulus of copper, 

 iron and lead, as in reducing mixed sulphides, the main efforts of 

 the smelter are directed towards obtaining " clean " slags, that is, 

 slags as free as possible from silver, absolute freedom being a 

 practical impossibility. Little is known as to the cause of slags 

 carrying large or small amounts of silver. In a valuable paper 

 on " Lead Slags " which appeared in the Chemical Neivs (Vol. 

 LVIL, pp. 4-7, 18-19, 37-38, 43-45, 57-58), M. W. lies says— 

 " Why should one slag be good and another bad ? " " The dissemi- 

 nation of matte globules does not to my mind satisfactorily 

 explain the silver-losses, since I have detached perfectly pure 

 crystals from the very heart of the pot from slags of all of the 

 above types, and as a general thing these crystals were found to 

 contain a larger amount of silver than the main body of the 

 slags ; the lead contents will usually be less." In Percy's "Metal- 

 lurgy" (Silver and Gold, Part I., p. 532) it is stated that when 

 running matte is of greater value than 80-100 ozs. silver per ton, 

 it is not practicable to make " clean " slags. 



It is well known that silver will concentrate in the last liquid 

 portions of its alloy with lead, and Pattinson's process depends 

 upon this fact, although it is usually explained differently. Some 

 observations of the writer have led him to conclude that silver 

 has the propei^ty of passing from the already solidified or solidi- 

 fying portion of a body, into the composition of which it enters, 

 into the last remaining liquid portion, and that perhaps high 

 silver slags may be due to some extent to this movement. 



Upon a recent occasion, when smelting a large quantity of rich 

 silver-bearing material, the following notes were made, and they 

 are presented with the hope that they may induce other smelters 

 to make observations in this direction. 



