—— 
ORIGIN OF GOLD NUGGETS. 333 
C. Délter, Solubility of Minerals (Monatsh. 11, p. 149), found 
that gold at 200C. in a sealed tube with a 5‘/ solution of Na,CO, 
or Na,SiO, is dissolved to the extent of 1-57 of the weight of 
the gold taken. 
Bischof also found that gold sulphide is slightly soluble in 
meteoric waters, and still more soluble in a saturated solution 
of hydrogen sulphide; and that it is also slightly soluble in 
persalts of iron. 
Newbery tested this by dissolving gold sulphide in a weak 
solution of an alkaline bicarbonate, and found that on introducing 
a chip of wood and a cube of pyrites that the gold was deposited 
on the pyrites. (See his paper On the Formation of Nuggets, 
Roy. Society, Victoria, 1868). 
I find that gold foil is attacked by a strong solution of sodium 
sulphide, in nine days a fillet of gold foil exposing about four 
square inches of surface, and weighing ‘6181 gramme, lost :0021 
gramme. Gold leaf treated with sodium sulphide still more 
readily yielded a solution containing gold. 
R. Daintree in his Geology of the Ballan District, Victorra, 1866 
says :—‘‘I had long come to the conclusion that most, if not all, 
the gold in the quartz reefs was derived from the rocks in which 
these reefs occur. That the strata themselves received their 
supply of gold at the period of their deposition from the ocean in 
which they were deposited. That the organic matter and the 
gases generated therefroin on decomposition, sulphuretted hydrogen 
&c. were the cause of the precipitation ; and that the amount of 
metallic deposit was in proportion to the amount of organic matter 
deposited with the organic sediment.” 
Sir. W. Logan says, (quoted by Daintree) ‘“‘ The observations 
_ among the gold bearing rocks of the Southern States seem to show 
that the precious metal was originally deposited in the beds of 
various sedimentary rocks, such as slates, quartzites and limestones, 
and that by a subsequent process, it has been, in some instances, 
accumulated in the veins which intersect these rocks.” 
