Value of Native Gold, dc. 221 
especially as regards the comparative amount of Gold and 
extraneous matter in mixed specimens, apply in strictness 
only to Gold from Mount Alexander: but there is much that 
will apply to Gold from California and New South Wales ; 
or, indeed, to that from any part of the world which is alloyed 
principally with Silver. 
I have not been able to procure specimens from California 
or from Sydney sufficient to enable me to carry on a series 
of experiments with regard to them, but I am in possession 
of the analysis of a considerable quantity both from Cali- 
fornia and Sydney ; and it will be interesting to compare the 
results obtained by analysis with those which I have deduced 
from my experiments,—and the Society will then be able to 
judge of the amount of confidence which can be placed in the 
Tables which form part of this communication. 
First, with regard to the Gold from California. 
The quantity of metal forwarded to the assayer was 21 lbs. 
9 oz. 6 dwts.: this, when melted and cast into an ingot, 
weighed 21 lbs. 1 oz. 0 dwts. 12 grs., showing a loss from the 
presence of extraneous matter of 8 oz. 5 dwts. 12 grs. Upon 
analysis this quantity of metal was found to contain 527 dwts. 
of pure Silver, or at the rate of 21 dwts. 18 grs. in the pound; 
or the proportion of Gold to Silver in metal was as 9°38 to 1. 
Tf a reference be now made to the first Table to ascertain 
the specific gravity of a specimen in which the Gold bears 
to the Silver, the proportion stated above, which, when 
ounces are taken as the total weight, will be equivalent to 
433°4 grains of Gold to 46°6 of Silver, we shall find that it 
lies somewhere between 17700 and 17900; and by making 
the proper allowance for the difference, the actual specific 
gravity will be’ 17809. 
Now, the value given in the Table of an ounce of Gold 
alloyed with Silver, whose specific gravity 1s 17°809, nee PATS 
T 3 
