Laboratory Tests. 45 
while the solution, after being freed from its values, is 
caught in a receiving tank from whence it is pumped 
back to the standardizing tanks and cyanide added until 
it is brought up to the proper strength for using again. 
The above tests should be conducted in such a way as 
to imitate as nearly as possible the actual operation of 
the cyanide mill. 
TESTING BY THE CHLORINATION PROCESS. 
Pass the pulverized sample through a forty mesh 
sieve, weigh out one pound of the ore and roast, if a sul- 
phide, to a dead roast, introduce the roasted ore into a 
glass-stoppered bottle containing 300cc hot water and 6.8 
gms. of each, bleaching powder and sulphuric acid (66° 
Baume). Agitate the bottle and its contents from four 
to eight hours, then filter off the solution, wash the pulp 
with water until the washing no longer gives a precipi- 
tate on testing for chlorine with silver nitrate. Now dry 
the pulp and assay it in the usual way. Having the as- 
say on the ore before and after treatment, the difference 
represents the loss in treatment. The above test is made 
on the basis of there being thirty pounds of each—sul- 
phuric acid and bleaching powder—used to the ton of ore 
in the regular milling process. These proportions should 
be varied, however, the proper amount of each chemi- 
cal required can be determined only by experiment. At 
the end of the: process of agitation there should be free 
chlorine present, which is indicated in the presence of 
ammonia water by giving off the characteristic fumes of 
ammonia-chloride. 
TESTING BY THE AMALGAMATION PROCESS. 
Pulverize the ore and pass it through an eighty 
mesh sieve. Weigh out 50 A. T., place in an ordinary 
gold pan and pan down to black sand. Wash the con- 
tents into a wide-necked bottle, add two ounces of mer- 
