Aluminium
Aluminium, or aluminium, is an extremely light, ductile and malleable metal, which is rapidly coming into favor for many purposes since the great improvements in its manufacture and the consequent reduction in cost. It can now be purchased in quantities at ninety cents per pound, which makes it nearly as cheap as copper, when the great difference in weight of a cubic foot of the two metals is considered. It is silvery in appearance, melts at 1,300 degrees F., has a specific gravity of 2.56 to 2.60, which is one-fourth the weight of silver, does not oxidize readily and resists most acids and alkalies, but is very easily attacked by others, especially when heated, or when present during chemical reactions on other metals. It is three times as ductile as silver, and has 50 per cent more tenacity or strength. Much nonsense has been written about this metal, such as that it is stronger than steel; will not rust; is not attacked by acids, etc., all of which are untrue. It is readily attacked by many chlorides, such as common salt (chloride of sodium), etc., and by some of the organic acids, in which respect it resembles silver. In regard to the hardening, tempering, etc., of the pure metal, comparatively little is known at present; but it is probable that as its use becomes more common it will be greatly improved in these respects, as has been done with iron. At all events, it will have an extended trial in the fine arts and mechanics, and it will probably displace platinum and nickel in the various alloys to some extent, on account of the great difference in weight. One great difficulty remaining to be overcome is that of soldering. At present it can be soldered only by using an alloy of which aluminium forms a part.
Aluminium forms alloys with many metals; those with copper, silver and tin are largely employed for many purposes, and their use is rapidly extending. The most important are those of copper, with which aluminium easily unites. See Alloys.