ON gold: its formation in our reefs. 161 



I have thought that in some of the analysis of cupi-eous gold 

 nuggets, the coppei' was prohably derived from a core of cupreous 

 sulphide, but tliis can hardly be so in all instances, as, in one 

 case which came under my notice, I found a speck of very dark 

 gold in the centre of a mass of native copper, which must have 

 contained at least 10 per cent, of copper, judging by the colour 

 of its clean surfaces. I also found several specks of brighter 

 gold in the same body of copper. 



THE ORIGIN OF THE GOLD. 



Admitting the reducing property of the metallic sulphides, and 

 their power to aggregate gold in massive forms the tirst question 

 suggests itself, is — what is the source of the gold 1 



Sonstadt has shown that every ton of sea-water contains one 

 grain of gold. Now we know that by far the greater portion of 

 the countiy rock, forming our continents, is of marine origin ; it 

 does not require a great stretch of the imagination, to believe, that 

 during the formation or deposition of the strata, now forming 

 dry land, the sti'ata became saturated with sea-water. Supposing 

 these rocks retained only three per cent, of their weight of sea- 

 water, even at this low estimate, every cubic mile of rock would 

 contain nearly 1,000,000 ounces of gold. 



Besides this, we can no doubt draw upon the gold existing in 

 the rocks in a native state. 



Some chemists have laid much stress upon the solvent power of 

 free chlorine, but we must consider that our rock masses are, for 

 the most part, alkaline, and hardly in a favourable condition for 

 the existence of free chlorine, but rather for hypo-chlorous acid, 

 a substance which has no solvent powers on gold. 



Clearly then, it is by other agents that this, gold has been 

 attacked and dissolved ; that is, if our reefs have been supplied 

 with gold so derived. I shall endeavour, in the second part, to 

 show what these are. 



II.. — Dealing with the various discoveries I have made 

 relative to the re-actions of gold and the other noble metals when 

 subject only to ordinary atmospheric or terrestrial agencies. 



For convenience of reference I have divided my obsevations and 

 remarks under this heading into the following divisions : — 

 a. — Sulphurization of gold. 

 b. — Oxidation of gold, 

 c. — The ageiicies which have brought the gold into the reefs. 



a. Sulphur izcUioji of gold. It is the opinion of chemists 

 generally, that gold is not amenable to those simple though feeble 

 agencies which are sufficient for the satisfaction and removal of 

 the so-called base metals. Prior to my investigations in 1870 

 there was no reason for believing otlierwise than that gold,, 

 remained as gold, "pure and undetiled," through all the mutations 

 which the other metals have undergone at the earth's surface. 



It is now many years since I first published my discovery that 



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