372 Transactions. — Chemistry. 



gold, and likely to occur in the interior parts of our rocks, are ferrous sulphate 

 of iron, organic matter, and metallic sulphides. These also reduce silver from 

 certain of its solutions, but, as already noted, the difficulty is in jSuding a 

 substance which will reduce these two metals simultaneously in coherent 

 forms, and from such kinds of solutions as generally permeate our rocks. 

 "With this double duty to perform, and limited in this manner as regards nature 

 of solvent, I cannot avoid thinking that but one of these reducing agents, 

 the metallic sulphides, will be found equal to the occasion. The ferrous 

 sulphate is thrown out at once from this service on account of its insolubility 

 in such a menstruum, while organic matter appears to have a decided tendency 

 to scatter the gold it reduces (see Art. LII), nor have we, as far as I am 

 aware, produced any true alloy of gold and silver by their use. 



I would not intend to convey the idea that such a mixed deposition is 

 impossible, but only that, from what we at present know of this subject, the 

 production of such an alloy by these means appears a very difiS.cult undertaking. 

 However, this particular question is, I understand, now being dealt with by 

 Mr. Daintree, late assistant geologist to the Victorian Geological Survey,* so 

 that the propriety or otherwise of retaining this theory of the origin of our 

 auriferous deposits in their lodes by the interaction of organic matter may be 

 left in abeyance until Mr. Daintree publishes the results of his inquiry, as 

 promised. 



I will therefore leave the question in this state, merely observing that 

 should Mr. Daintree be unable to obtain the results he is in search of, I 

 shall then claim for our metallic sulphides the sole duty of depositing at least 

 that portion of our native gold which occurs in the reefs or fissures of our 

 metamorphic rocks. 



Art. LII. — Critical Notes upon the Alleged Nuclear Action of Gold upon 

 Gold reduced from Solution by Organic Matter. By W. Skey, Analyst 

 to the Geological Survey of New Zealand. 



[Read hefore the Wellington Philosophical Society, 23rd October, 1872.] 



In a paper upon the formation of gold nuggets which appeared in Part I., 

 Vol. YIII., of the Transactions and Proceedings of the Royal Society of 

 Victoria, the author, Mr. C. Wilkinson, states in reference to the question as 

 to the origin of gold nuggets that " Mr. Daintree, formerly of our Geological 

 Survey (that of Victoria) had on one occasion prepared for photographic use a 

 solution of chloride of gold, leaving in it a small piece of metallic gold 



* "Athenaeum," 22nd July, 1871. 



