52 Formation of Gold Nuggets. 



gas is inversely as its bulk. When the barometer stands afe 

 30 inches and the thermometer at 80°, the elastic force of 

 the vapour of water being I'OIO of an inch of mercury, a 

 cubic foot of air saturated with moisture, would, when diy, 

 contract to 1669 - 824 inches. This shows that a some- 

 what different result would attend the use of moist air. 



Art. V. — TJie Introduction of Gold to, and the Formation 

 of Nuggets in, the Auriferous Drifts. By J. Cosmo 

 Newbery, B. Sc, Analyst of the Geological Survey of 

 Victoria. 



[Read 30th April, 1868.] 



At the meeting of the Society in September, 1866, Mr. 

 Chas. Wilkinson read a paper on the growth of nuggets, in 

 which he stated that I was carrying out a series of experi- 

 ments based on the very interesting discoveries he had 

 made. 



Before describing my experiments and their results, it may 

 be well for me to give an abstract of the arguments used for 

 and against the denudation theory and in favour of what 

 seems to some a rather ludicrous idea — the growth of nuggets 

 in the drifts. 



Through the kindness of Mr. Ulrich, I have been able to 

 read the latest ideas of the eminent chemical geologist, Pro- 

 fessor Bischoff, from whom I shall freely quote. 



That some portion of the gold found in the drifts has been 

 derived from the quartz reefs at the same time that the reefs 

 themselves were formed, there can be no doubt, but the 

 absence of large nuggets in the reefs and the marked differ- 

 ence that exists between mud of the drift gold and that 

 from the reefs, tends to make us believe that some portion of 

 it had some other origin or was transferred from the reefs to 

 the drifts by some means other than by denudation. Even 

 if we admit that the large nuggets may have been derived 

 from the reefs by denudation — (for there is a theory that the 

 reefs were much richer in the portions removed to form the 

 drifts, than they are as they now exist) — we must remem- 

 ber that the nuggets consist of nearly the heaviest known 

 matter, offering but a very small surface of attack, when com- 

 pared with the other materials acted on by the same force 

 and at the same time ; it therefore appears strange that these 



