AND OTHER METALS FROM PYRITES. 99 
coon none of the above pesca agents had any ae 
ciently rapid, and fat ie that this was also the it 
permanganate. 4 ang ay to be of considerable value, 
as the gold and a at oth be obtained in solution, from 
which the former could be 0 3a by filtering the hot solu- 
tion through finely divided meta i 
quantity would be dissolved, which, with the silver originall 
however, that copper in any form gore: 27807 both ad aad 
silver from the solution, or at all events that thes > meulane were 
not dissolved until the copper all gone into aleliand also, 
that if the copper w ut as sulphide, the pats! was trans- 
rmed into sulphide Eee is insoluble. copper dissol = 
tion being kept a 
po ortion of suigints arsenical pyrites was digested at 212° for 
twelve hours with } oz.ferrocyanide of potassium, 32 grs. oxide of 
manganese (20 lbs. per ton), and sufficient water 
soda to aks a cream—the solution gees 9 ozs. = dwts. 19 grs. 
gold per ton, leaving 1 oz. 9 dwts. 15 grs. This was the best 
result obtained with this pate Fe Fe yield with. spake oxidizing 
agents and by more prolonged digestion being all somewhat lower. 
With Mariner’s Reef pyrites trials were made with each 
oxidizing agent in succession, the duration of the digestion 
; s a ” ; ; 
thirty-five to forty times the theoretical quanti ve the best 
ts. The nai Ste used had been sonated ih h salt and 
extracted with acid, and Pea so little copper that 50 ham 
ms pas with nitric acid, the solution made alkaline by amm 
and made up to 50 wes had pr a = faint colouration in a atindae: 
3 inches deep. It contained— 
ozs. dwts. grs. 
Gold . ace Bei es G° 49 
Silver ... ale ies wan ae Ak &.. 
