1889-90.] ARSENIC AND SULPHUR. 147 



Now allow me to draw your attention to the advantages to be derived 

 from this process. In the first place you must all be aware that the 

 matrix of an ore, it matters not whether it be quartz, calc-spar or any 

 other mineral, when heated to redness and either suddenly immersed in 

 water, or water thrown over it, will be rendered quite brittle, and will fall 

 to pieces with the least concussion or blow, and even with some the dis- 

 integration is so great that they will break up during their immersion or 

 while the water is being thrown over them. 



Now this would be a source of great and general economy, the stamp- 

 ing expenses would be reduced ; for instead of each stamp doing one ton 

 per diem, they would do five tons ; five days' work would be done in one ; 

 consequently saving five days' tear and wear of plant, also five days' 

 steam and fuel, besides five days' wages to the workmen and other items 

 of which I shall make no mention, unless to say that the returns would 

 be quicker, thus making it a point of great importance. 



I am of the opinion that many men of our profession are ignorant ot 

 the cause of the loss of a portion, if not all of the gold and silver in an 

 ore, by assay, when treated by the amalgamation process, and which they 

 call free gold, and which appears so to the eye, but in reality is covered 

 with a thin film of sulphur which renders it impervious to the mercury 

 to form an amalgam. It seems strange this has never been discovered 

 before, but my father and I have proved it to be true, and were intending 

 to publish a paper on it, but were anticipated by Mr. Skey, analytical 

 chemist for the New Zealand Geological survey, who published a paper 

 on this subject under the title of " The absorption of Sulphur by Gold 

 and its effects in retarding amalgamation." Now, this sulphur can be 

 got rid of by roasting at the proper temperature, and as to expenditure 

 have I not shown the advantage in less labor and mechanical power being 

 required in the further treatment of these ores ? 



Another cause of great loss is the carrying away by water of the float 

 gold. The cause of its floating is that, although it has the highest 

 specific gravity or density of all the metals, except platinum, iridium, 

 and osmium, which are 2i'50, 2ri5, and 21-4 respectively, gold being 

 I9"50 and thus almost twenty times heavier than water, it has such a 

 great surface in comparison to its weight that the water resists its sinking, 

 and also the hydrodynamical force of the water in carrying it away even 

 was it inclined to sink, keeps it in suspension and prevents it from doing 

 so ; thus it is carried over the amalgamated riffle plates and lost. Now 

 had the ore containing this fine gold been treated according to the pro- 

 cess I have described, the fine and leaf gold would have been converted 

 into globules, and even were the globules only the size of a pin's point 



