ALUMINUM, a metal discovered by Wailer in 1827, as a gray powder, but in 1847 in the form of small, glittering metallic globules. In 1854, H. St. Clair Deville isolated aluminum into a state of almost perfect purity. He found that aluminum could be prepared in a com pact form at a comparatively small ex pense. It is a white metal, somewhat resembling silver, but possessing a bluish hue, which reminds one of zinc. Exposed to dry or moist air, it is unal terable, and does not oxidize or tarnish like most common metals. Salt water affects it less than it does silver, tin, or copper. Neither cold nor hot water has any action upon it. When cast into molds, it is a soft metal like pure silver, and has a density of 2.56; but when ham mered or rolled, it becomes as hard as iron, and its density increases to 2.67. It is, therefore, a very light metal, be ing lighter than glass, and only one fourth as heavy as silver.
Aluminum has, in recent years, come into common use for culinary utensils and other domestic uses, and in manu factured articles where strength and lightness are requisites. It is espe cially valuable in the making of aero planes and automobiles. Not being acted upon by organic secretions, it is used for optical, surgical, and chemical in struments and apparatus. Aluminum leaf and wire may be employed with great advantage in place of silver leaf for decoration, or silver wire for em broidery. Of late it has come to be used in shipbuilding, especially for torpedo boats. And as it is especially suitable for cooking-vessels, efforts to cast it for pots and pans have often been made, but unsuccessfully till 1895 when aluminum was, weight for weight, three times the price of copper, but, bulk for bulk, the cheaper metal. In 1855 Napoleon III. paid
the expense for making industrial use of aluminum at Javel. Many other manu factories of aluminum were also started about the same time in France. In 1856, Alfred Mounier produced aluminum at Camden. In 1857, the price of alumi num was from $28 to $32 a pound. Be tween 1862 and 1877 it ranged from $12 upward, and when in 1888 electrical methods of production were used, the price of aluminum was reduced to less than $1. In recent years it has dropped to a quarter and even a fifth of that price.
The sources most used for the produc tion of aluminum are bauxite, a mineral first found near Baux, but since then found in Styria in Austria, in Ireland, and in many places in the United States; and cryolite, found on the W. coast of Greenland. There is no other useful metal, iron not excepted, which is widely scattered over the earth and which oc curs in such abundance. The value of the aluminum produced in the United States in 1918 was $41,159,000. The pro duction of bauxite was 569,000 long tons, valued at $3,244,000. For occurrence and production in the United States, see BAUXITE.
Aluminum Alloys.—The aluminum bronzes, now becoming so generally in troduced, are the alloys of aluminum and copper, in which the amount of cop per considerably exceeds that of alumi num. The value of these aluminum bronzes consists in their non-corrosive properties and in their strength.