On Gold Refining by Chlorine Gas. 



157 



Art. XI. — On Gold Refining by Chlorine Gas, by F. B. Miller, 

 Esq., F.C.S., Assay er in the Sydney Branch of the Royal 

 Mint. 



[Read before the Society, 1st December, 1869.] 



There is no recorded instance of gold having been found in an 

 absolutely pure state. Every natural alloy of gold (or native 

 gold as it is called by mineralogists) contains more or less silver, 

 and in almost all bullion resulting from the melting of Australian 

 alluvial gold the portion that is not gold consists chiefly of silver, 

 with only a very small proportion of foreign metals, usually 

 copper and iron, with occasionally a little lead or antimony, and 

 sometimes a trace of tin, iridium, &c. This, however, though 

 true generally, is not always the case with gold obtained from 

 quartz by amalgamation, as the mercury occasionally reduces 

 and takes up other metals, as well as the gold, which appear in 

 the bullion on melting. The accompanying table will give some 

 idea of the proportion of the precious metals contained in the 

 gold from the various districts of New South "Wales after 

 melting : — 



TABLE shewing the proportion of Gold and Silver, in charac- 

 teristic samples of Gold-dust, from various localities in New 

 South "Wales (after melting). 



Locality 



r Boonoo Boonoo 



£ I Fairfield 



j2 ■ Timbarra 



|1 Peel River 



jz; I Rocky River 



iNundle 



rBathurst 



Sofala 



Tuena 



Ophir 



Tambaroora 



I Turon 



I Hargraves 



LWindeyer 



rBurrangong 



| Adelong 



Braidwood 



Emu Creek 



Delegate 



Nerigundah 



It will be seen that the most argentiferous is that from Boonoo 

 Boonoo in the north, containing as much as 34 per cent, of 



-I 



<{ 



Gold 



Silver 



in 1000 parts. 



in 1000 parts. 



854 to 659 .. 



337 to 298 



872 



121 



708 to 898 .. 



280 to 97 



929 



67 



934 to 962 .. 



61 to 33 



923 to 937 .. 



66 to 63 



827 to 903 .. 



164 to 92 



929 to 933 .. 



66 to 63 



943 



54 



915 



82 



943 to 954 .. 



54 to 42 



918 to 928 .. 



78 to 68 



915 



83 



946 to 959 .. 



53 to 37 



948 



48 



946 to 951 .. 



52 to 45 



928 to 931 .. 



. 67 to 62 



971 



27 



971 



27 



983 



15 



