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480 sixteen days, and in winter twenty-five days. The way in which the thorough amalgamation and separation were afterwards carried on, by means of certain machinery, was fully explained by the 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 perfect 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 thorough 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 over 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, notwithstanding 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; certainly 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.