204 ALUMINIUM, ANTIMONY 



soda-water, as soda quickly attacks aluminium ; nor should 

 the brown film which forms on the inside surface of aluminium 

 kettles be removed, for this is caused by the action of boiling 

 water on the metal, and serves to protect it. 



SOURCES OF SUPPLY. Bauxite clay occurs in Antrim in the 

 north of Ireland. It is sent by way of Loch Linnhe and the 

 Caledonian Canal to be treated at the works situated by the 

 Falls of Foyers on Loch Ness. There are also known deposits 

 in India, and British Guiana, and in New South Wales 

 and Western Australia, but at present these are not much 

 worked. 



In Canada there are great aluminium works at Shawinigan 

 Falls, twenty-one miles from the mouth of the St. Maurice 

 River, which flows south into the St. Lawrence at Three 

 Rivers ; but the bauxite is imported from the United States, 

 and after the aluminium is obtained it is exported to that 

 country. 



We have not, however, at present enough to supply our 

 needs, and we import it from foreign countries. 



ANTIMONY is a white metal very much like tin in appear- 

 ance. It is hard and brittle, and a bad conductor of heat. 

 Sometimes it is found alone, but more often in combination 

 with sulphur, forming a grey ore called stibnite. To remove the 

 sulphur the ore is powdered, and mixed with old pieces of iron, 

 and heated. The iron then unites with the sulphur, and the 

 antimony is set free. 



On account of its brittleness antimony is not used alone, 

 but its extreme hardness makes it a very useful component of 

 alloys in combination with softer metals. It is used, for 

 instance, with lead to make bullets, especially those called 

 shrapnel, contained in explosive shells. Britannia metal, too, 

 is a hard alloy consisting chiefly of block tin and antimony. 



Molten antimony expands as it cools, and for this reason 

 is used with other metals to form alloys, which are to be 

 moulded to an exact shape. In printing, the raised letters 

 called type are made by pouring molten type-metal, a mixture 



