480 'Proceedings. 



sixteen days, and in winter twenty-five days. Tlie way in wMch tlie thorougli 

 amalgamation and separation were afterwards carried on, by means of certain 

 macliinery, was fully explained by tbe speaker. Then there was another 

 process, by which ores were roasted, and mixed with salt, and placed in 

 barrels having certain machinery, for separation and amalgamation. So per- 

 fect was this system that a very minute portion of metal was left in the ore. 

 The heat, dews, wet, and the magnetic state of the atmosphere, all played 

 a part towards the extraction of the metal from the ore. They might say 

 this process was very rough, but if it saved the gold, what mattered it ? At 

 present, at the Thames, a great part — he might say the greater part — of the 

 gold was lost, even with the best machinery. One reason of which, he believed, 

 was because the process was gone through far too quickly ; and another 

 thing that militated against the thoroug*h saving of gold was the immense 

 quantity of undecomposed sulphurets that pass through the mills. Speaking 

 of the amount of gold that might be extracted from these iron pyrites. Dr. 

 Purchas said that in Australia as much as forty ounces to the ton had been 

 obtained. 



Captain Hutton said ninety in some places. 



Dr. Purchas said that, if that were the case, there must be an enormous 

 quantity of gold lost at the Thames. He was much struck, in reading ov^ 

 a book on the subject of gold separating and amalgamating, to find that in 

 one mine in California a shaft had been sunk 1,300 feet, and yet, notwith- 

 standing the immense depth, the shareholders said that it paid better than 

 ever it had done before. Even then it was only yielding an ounce to the ton ; 

 and if this could be done in California, surely it could be done here where 

 there was a yield of three or four ounces. Another thing he wished to say 

 about the Thames, and that was, that a great deal of the soil that was thrown 

 away, in fact, in the majority of cases, contained a large percentage of gold. 



Captain Hutton asked whether the earth was meant, or the casing of the 

 veins. 



Dr. Purchas said it would be the casing he was referring to. "With regard 

 to the processes he had mentioned of getting the gold from the stone, many 

 people would grumble at the time taken, but everything of this sort required 

 to be done by companies. He thought it was a mistake to attempt to mine 

 at the Thames as diggers were doing at the present time ; the right way to 

 do it was to mine with companies, and with large areas of ground and proper 

 machinery. He believed an immense amount of labour was wasted ; cer- 

 tainly a large amount of gold was. 



Mr. Grillies said he would not discuss the question of gold saving, but 

 there was one thing which he would ask the Society and the people at large 

 not to admit, and that was, that large public companies were always the best. 



