1008 



TIN 



Production of the Dutch Tin Mines for the last 19 years. 



Imports of Tin in the year 1873. 



To test the quality of tin, dissolve a certain weight of it with heat in hydrochloric 

 acid ; should it contain arsenic, brown-black flocks will be separated during the solu- 

 tion, and arseniuretted hydrogen gas will be disengaged, which, on being burned at 

 a jot, will deposit the usual grey film of metallic arsenic upon a white saucer held a 

 little way above the flame. Other metals present in the tin are to be sought for by 

 treating the above solution with nitric acid of spec. grav. 1'16, first in the cold, and at 

 last with heat and a small excess of acid. When the action is over, the supernatant 

 liquid is to be decanted off the peroxidised tin, which is to be washed with very dilute 

 nitric acid, and both liquors are to be evaporated to dissipate the acid excess. If, on 

 the addition of water to the concentrated liquor, a white powder falls, it is a proof 

 that the tin contains bismuth ; if, on adding sulphate of ammonia, a white precipitate 

 appears, the tin contains lead ; water of ammonia added to supersaturation will occa- 

 sion reddish-brown flocks, if iron is present ; and on evaporating the supernatant 

 liquid to dryness, the copper will be obtained. 



1 1,000 Banca slabs weigh about ?2 tons ; the average weight of 1,000 slabs Straits tin being from 

 35 to 40 tons. The weight of the Billiton slabs is the same as the Banca. 



