724 ALUMINUM. 



weight only one-eighth as much, it must be relatively about thirty-two 

 times as cheap. In other words, the purchaser would find it economi- 

 cal to use aluminum in preference to silver for everything to which it is 

 adapted. As a conductor of electricity it equals silver, and is eight 

 times better than iron, and as a conductor of heat it excels auy other 

 metal known. Neither air nor water, hot or cold, affects it, and it re- 

 sists all acids except hydrochloric. It slowly yields to a mixture of salt 

 and vinegar with a result as harmless as clay itself. It does not seem 

 to be affected by saliva, perspiration, or other animal agents. Hydro- 

 gen, nitrogen, sulphur, and carbon do not affect it, but it is rapidly 

 attacked by chlorine, fluorine, iodine, and bromine. From the above 

 observation aluminum does not seem to have an intimate analogy with 

 any other known metal, though Eichards aud Woehler place it near to 

 silicon and boron in the carbon series. 



Aluminum melts slowly at about 700° C. (1292° F.), without a flux, and 

 in an ordinary uncovered earthen crucible lined with carbon. The 

 pieces of divided metal are first dipped in benzine to clean them, and 

 if necessary, are treated with nitric acid and then put in the crucible 

 little by little. 



A cinder reniaius at the bottom of the crucible. The molten metal 

 may be cast either in metallic molds or in very dry porous sand with 

 numerous vents. Deville prefers a ])lumbago crucible without a lid, and 

 exposes the red-hot metal for a long time to the o^jen air to allow the 

 exhalation of the acid fumes, after which the surface is skimmed without 

 loss of metal. It is then cast into ingots. To get perfectly clean results 

 this process is repeated three or four times. The pure metal thus ob- 

 tained improves in color with using, while what is less pure tarnishes in 

 time, though perhaps equally brilliant on first casting. 



The Aluminum Company, with offices at 115 Cannon street, London, 

 and works at Oldbury, near Birmingham, issued a price-list ISTovera- 

 ber 1, 1889, from which we quote aluminum, 99^ to 99f per cent., purity 

 guarantied, 15 shillings per pound ; 98 to 99, 15 shillings per pound j 

 95 to 9G, 12 shillings a pound. 



The first article manufactured from pure aluminum was a rattle for 

 the young Prince Imperial of France, in 185G, the sonorousness of which 

 was much admired. It was next made into je'welry, medals, and inlaid 

 work. Its extreme lightness led to its being used for sextants, eye- 

 glasses, opera-glasses, and the tubes of telescopes. It has been found 

 useful for the beams of balances, for delicate weights, and in the form 

 of fine wire for embroidery. Culinary articles made from it were to be 

 seen at the London exhibition in 1862, for which it seemed admirably 

 adapted on account of its lightness and immunity from corrosion. 



Experiments have been rapidly mutiplied of late, under the encour- 

 agement given by reason of the increased cheapness of the metal, aud 

 a promising field is surely opening for its employment for many orna- 

 mental and useful purposes. The processes of soldering, welding, ve- 



