n8 THE PROSPECTOR'S HANDBOOK. 



liquid. The button gradually becomes more convex, and at 

 last a mirror-like speck of bright silver or gold, or both, is left. 

 The cupel should then be gradually drawn by means of the 

 cupel tongs to the muffle door, so that the metal may not 

 " spit," which it might do were the cupel to be too suddenly 

 cooled in the cold air. In form the little button should, if 

 a proper one, be well rounded, crystalline below, and easily 

 detached from the cupel. As the button may contain both 

 silver and gold, it should, after being cleaned by brushing 

 with a paint brush and weighed, be removed and subjected 

 to the action of nitric acid, in order that the silver may be 

 dissolved and the gold left in the form of a dark powder; 

 after this the gold may be weighed, and the original weight 

 of the button, minus the weight of the gold, will represent 

 that of the silver. 



N.B. To separate the two metals in the button, place 

 the button in a test tube with about ten times its weight in 

 nitric acid (dilute), and boil for about a quarter of an hour ; 

 the silver will be dissolved and the gold left. The liquid 

 should be decanted, a little pure nitric acid poured on the 

 gold powder to make sure that no silver remains, and the 

 liquid poured off and the gold washed and dried. If the 

 appearance of the button suggests that it is rich in gold, 

 some silver must be fused with it before acid is poured on, 

 as unless there be three times the amount of silver 

 as gold, the " parting," as the above process is called, will be 

 incomplete. 



Indications of the presence of metals in the ore known 

 by cupel stains : 



Antimony pale yellow to brownish red scoria; some- 

 times the cupel cracks. Arsenic White or pale yellow 

 scoria. Cobalt dark green scoria and greenish stain. Capper 

 green or grey, dark red or brown. Iron dark red 

 brown. Lead straw or orange colour. Manganese dark 

 bluish black stain. Nickel greenish stain; scoria, dark 

 green. Palladium and Platinum greenish stain ; the button 

 will be veiy crystalline. Tin grey scoria ; tin produces 

 " freezing." Zinc yellow on cupel ; the cupel is corroded. 



