238 HISTORY OF CALIFORNIA. 



appearance, and we therefore append the following 

 short table. The specific gravity of water is assumed 

 to be unity : 



Osmium .... 21| 



Platinum . . . 19 \ 22 not hammered. 



Iridium .... 18 T 7 ff 



Gold 15| 19 ditto 



Mercury . . . . 13 \ 



Palladium . . . H T 7 ff 



Lead 11* 



Rhodium . . . lOf 



Silver 10 



Copper .... 7| 8 



Brass . . . . 8| 



Lead ore (galena) 7^ 



Copper pyrites . 5 



Iron pyrites . . 4 



Diamond . . . 3 



Sand .... 2f 3 



By the help of this table the value of auriferous 

 sand may also be in some degree estimated, since, as 

 will be seen, the specific gravity of most of the sands 

 is under 3, while that of the most impure gold is 12 ; 

 so that if the specific gravity of the sands them 

 selves, when experimented on, is much greater than 

 that of ordinary sand, it is likely that the excess will 

 be for the most part gold, in a district otherwise known 

 to be auriferous : the greater the specific gravity, too, 

 the greater probability there is, of this being the cause. 

 It may also be worth while to mention here, that the 

 specific gravity of those pepitas or lumps of gold which 

 present a fine yellow color varies generally from 14-Sjj 

 to 18 T 8 jj ; but when much paler they may range as low 



* A very rough estimate of the value of specimens of native gold 

 may be obtained by multiplying the specific gravity by 4 ; the result 

 gives the value in shillings nearly. 



