218 TIN 



Pure tin ore or cassiterite is a compound of tin and oxygen, 

 and the removal of the oxygen is effected by heating the ore 

 in a furnace with coal and lime. The oxygen combines with 

 the carbon of the coal, and the lime with the other impurities 

 (for the ore is seldom pure), and the tin is set free ; it is run off, 

 and poured into moulds, where it forms blocks or ingots of tin. 



Pure tin is a silvery- white metal, harder than lead, though 

 not so hard as gold. It is so malleable that it can be hammered 

 out to the thinness of roVoth part of an inch. These thin 

 leaves, or, as they are called, tinfoil, are used for making 

 capsules, for wrapping up delicate articles and for many other 

 purposes. 



Alloyed with lead, tin forms pewter ; with copper, bronze. 

 It possesses one great advantage over iron in that it is but 

 slightly acted upon by air and water, whereas iron very quickly 

 rusts and wears away. 



For this reason tin is used as a coating for iron, and thus 

 a substance is obtained having the strength of iron, and the 

 air-resisting power of tin. This tinplate industry is chiefly 

 carried on at Swansea in South Wales. When the iron has 

 been cut to the required size it is subjected to various processes 

 until it has become quite clean and bright. It is then immersed 

 in melted grease, and left until it is perfectly coated, after 

 which it is dipped into a bath of molten tin. 



Afterwards the superfluous tin is removed by putting the 

 plates into a vessel containing tallow and palm oil, maintained 

 at a temperature just high enough to allow the tin to run off. 

 (The melting-point of tin is 449 F.) 



Besides Cornwall and the Malay Peninsula, tin is mined in 

 Tasmania, where it forms one of the most important mineral 

 products. The best-known mine is at Mount Bischoff, in the 

 west of the island, but there are others. Tin-smelting is carried 

 on at Launceston. 



Queensland. The Herberton district of Northern Queens- 

 land is the principal, though by no means the only, tin-field 

 The port of Cairns is the outlet for this district. 



