Proceedings. 163 



cliemical analysis of a few grains of the gold, and found it alloyed with silver in 

 the following proportions : — 



Gold 7-4275 



Silver.. 2-06 



9-4875 



The weight of this specimen in water previous to analysis was 8-905, (hence 

 the specific gravity 16-2875.) ]N"ow, substituting the specific gravity of silver 

 (10-474) for that of quartz, and takmg the specific gi-avity of cast gold as stated in 

 Youj." Excellency's paper, we have — 

 «= 9-4875 = 0-9771518 

 h = 19-258 = 1-2846112 



2-2617630 = 182-71 



8-905 = 0-9496339 

 19-258 =: 1-2846112 





2-2342451 = 



= 0-2381716 

 = 1-0191126 



171-492 

 9-4875 



1Q0'07Qt; 









1-7305 z 

 c = 10-474 



1-7305 



c—b = 8-784 z 



1-2572832 

 =. -9436923 





•3135909 == 2.0587 = quantity of silver. 

 The quantity of silver foimd by analysis was 2-06, — an approximation so close 

 that, considering the small quantity operated upon, it must be considered acci- 

 dental. As I thought it desu'able to test whether the metals in combinicig increased 

 in density or not, I selected anew sovereign, ajid by means of a balance whose beam 

 when unloaded was depressed more than |ths of an iach with i-th of a gi-ain, I 

 foimd the weight in air and ia water to be : — 



In air 4*5035 drams avoird. = 123-1426 grs. = a 



In water 4-248 „ „ = 116-15625 grs. z= e 



.•. Specific gravity 17-62623 



New standard British gold consists of gold 22 parts, copper 2 parts. Taking 

 the specific gravity of hammered gold to be 19-361 and that of copper 8-878, 

 we find by the following formula, — 



■=Sp. Gr. 



a — •! 



(6_1) (a^y) (c_i) y j 



h 



That the Specific Gravity of standard gold is 17.62632. The weigliings were made 

 with the greatest care, and the difference between the Specific Gravity found by 

 actual weighing, and that foimd by computation, is too small to be noticed. It 



