THE FUTURE OF ALUMINUM.

Otago Witness, Issue 2085, 8 February 1894, Page 16

THE FUTURE OF ALUMINUM.

The future of aluminum is a subject attracting much attention just now in technical circles. It does not exist in Nature, says the London Spectator, in any form perceptible by the senses. There is no such thing as aluminum nugget or aluminum dust It cannot be crushed out or washed out, or even burnt out of the earth, except with the aid of the electric furnace at a temperature of GCOOdeg Fahr. ; yet it is present in every load of London clay, and wherever else clay beds lie it exists potentially in quantities and over areas to which even the coal measures cannot be compared either for richness or extent. When once obtained from the clay, its peculiar properties are more obvious and striking than those of any other material. It is beautiful to the eye — whiter than 6ilver, and indestructible by contact with the air. It neither rusts nor tarnishes, is Btrong, elastic, and so light that the imagination almost refuses to conceive it as a metal, the connection between heaviness and strength being almost as firmly established in most minds as that between heaviness and warmth, and refusing to admit any comparison between the comfort afforded by an eiderdown or a sheepskin. The weight is little more than one-third of the corresponding bulk of iron, and of course far less than that in tbe proportionate amount of silver, gold, or lead.

The so-called " aluminum gold," of which watch chains and trinkets were commonly made some years ago, is merely an alloy of copper containing a small percentage of aluminum, which gave to the copper brightDess and hardness, with absolute freedom from tarnish. "Aluminum bronze," the material of which the Austrian field-guns are constructed, also contains only some 6 per cent, of aluminum, though the material so produced is of extreme hardness and value for the purposes for which it is used. But the value of pure aluminum — light, strong, non-corroding, lustrous, and beautiful to tbe eye, inoffensive to the senses of taste and smell, and so malleable that (like gold) it can be beaten out into thin foil or drawn into fine wire — is such as to offer an inducement to the discovery of a cheap and simple method of extracting the boundless store in the clay-beds of the world hardly exceeded by the desire to discover the philosopher's stone itself. Nowhere, indeed, does the old fancj of the transmutation of metals come nearer an apparent realisation than in the change from masses of shapeless clay into white and shining blocks of silvery aluminum. Even now, with the existing methods of elaborate chemical treatment, or the intense heat of the electrical furnace, pure aluminum can be bought for 2s per lb in Germany and at 2s 6d per lb in England. Good gun metal — not the rubbish which is sold as " brass " for door knobs and curtain poles and other he uphold fittings — costs 6 d per lb ; but, as the quantity of aluminum represented by a pound weight ia three times that of an equal weight of copper, the cost of the aluminum, bulk for bulk, is in the proportion of 9d to that of 6d for tbe copper. Compared with, tbe 80-called brass, it i& already equally cheap and equally strong, with far greater lightness and beauty.

The present cost of aluminum, though still higher than any of tbe cheap metals, has brought it within the range of everyday life, and its present uses, limited as they are, necessarily bear sotre relation to the great question of the future of tho new metal, and the possibility of realising the hopes of the metal-worker and the engineer. For all personal equipment which must be carried by the owner, a'u , mum is rapidly taking the place of every oth< r cr^al. Its lightness is its obvious recommendation in this case. In tbe German cavalry, even the stirrup "irons" are now made of aluminum. The men's water bottles are also oE the same light and strong material. In binoculars for field use, and all kinds of scientific instruments for distant and toilsome expeditions, such as Dr Nassen's arctic journeys, or observations on high mountains, the same metal takes the place of the heavier brass, when the saving in weight so secured may often make the difference between scientific success or failure. Nearly all tbe small

articles of luxury and ornament usually made in silver or brass are now produced in aluminum, though where weight is rrot a drawback, the gain is rather one in appearance than in construction. But aluminum thimblesj penholders, paper-knives, flasks, or cup 3 are so far superior to those made of the ordinary materials that no one who has once made use of them in the new metal will readily return to the older form.

But ifc is not as a mere accessory to comfort and convenience that real development of the new metal should lie. It is for use at sea that its most marked quality of lightness obviously fits it. The marine engineer, and the naval architect, who are already looking in this direction for a reduction in the weight which is inseparable from loss of efficiency, whether in speed or cargo, cannot neglect the possibilities of a metal which, when mixed in the proportion of 1 to 50, gives to aluminum brotze a hardness and toughness which make it almost as reliable as steel, and which, if the proportions could be reversed, and the streßgth preserved, would reduce the weights of ships and machinery alike by two-thirds. That is a problem which awaits the metallurgists for solution. The reduction in cost, judging by analogy, can only be a question of time and research. The best steel now costa little more than £d per lb, while aluminum is 50 times that price. Aluminum exists in far greater quantities than iron, is more widely distributed, and neither the limits of time nor the history of metallurgy forbid us to conjecture that, as the world has seen its age of stone, its age of bronze, and its age of iron, so it may before long have embarked on a new and even more prosperous era — the age aluminum.