Dusortee vacelia in HNO, Assaying. 39 
Bae F dupes. 
GENERAL FORMULA. 
SMES iow ib oss 6 as ahe smn ev e's an 10 grammes 
Scda-Bicarbonate ............. 15 grammes 
Carb. Potassium .............. 10 grammes 
OE) A itties stiles vo e's, CORKS oF 7? grammes 
MRM rata 5 hays Shc es phe es die vee .. 5 grammes 
Lg 0) ee 3 grammes 
Salt cover, and three iron nails if a sulphide ore. 
Run at a moderate heat for from twelve to fifteen min- 
utes, or to complete fusion; then remove the crucible, 
take out nails, cover as rapidly as possible, and when 
stone cool break the crucible, detach lead button and 
hammer into a cube. The weight of button in grammes 
multiplied by ten, gives the ore’s percentage of metallic 
lead. 
COPPER. 
Wet Process for the Assay of Copper Ores.—(1) 
Treat one gramme of the finely pulverized ore in a 
(250ce capacity) flat-bottomed flask or casserole, with 
Yee of nitric acid, 5ce sulphuric acid, and if the ore is a 
heavy sulphide add one gramme of potassium chlorate 
(after boiling). Heat until all red fumes are gone, or 
until the nitric acid has been driven off, and all the cop- 
per is in solution. Now let cool and add seven grammes 
pure zinc, cut into thin strips, and 50cc of water. 
Shake the contents of the flask in order to 
break up any cake formed in the bottom and 
allow to stand fifteen minutes, then add 50ce 
water and 10cc sulphuric acid. Let cool thoroughly. 
The copper has been precipitated as metallic copper. 
(2) The solution of zine having been completed, fill up 
to the neck with water, allow to settle for about five 
