468 



METALLURGY. 



gen, iron, and silicon. The value of the material 

 is just as great after the tool has outlived its 

 usefulness as it was at the beginning, and for all 

 cases in which nonmagnetic properties, or high 

 conductivity, or extremely uniform and perma- 

 nent behavior are required, you have the ideal 

 metal." 



Aluminum, according to E. Hunt, of the Pitts- 

 burg Reduction Company, permanently loses 

 much of its rigidity, and temporarily a large 

 proportion of its tensile strength, if it is raised 

 to a temperature of 400 to 500 F. By cold 

 hammering, rolling, stamping, drawing, etc., the 

 metal can be greatly hardened and stiffened as 

 well as by the addition of foreign metals. A 

 small percentage of silver, chromium, manga- 

 nese, tungsten, or titanium largely improves the 

 color of aluminum, bringing its resemblance to 

 silver much closer. It is in the best condition 

 for rolling between 200 to 300' F., and can be 

 easily rolled Tott f an i ncn thick. 



Aluminum has been used as the material of 

 two French boats, the " Vendenessa," designed 

 for a light yacht, and the "Jules Davoust," in- 

 tended foF the exploration of the river Niger. 



Another application of aluminum is its em- 

 ployment in the manufacture of sound-cases, or 

 bodies of violins and other string instruments. 

 The sonorous properties of the metal are claimed 

 to be very similar to those of steel. 



An aluminum solder devised by Mr. Joseph 

 Richards and used by the Swiss Aluminum 

 Company derives its efficacy from the incorpo- 

 ration of a small percentage of phosphorus. The 

 best alloy thus prepared contains zinc, tin, alu- 

 minum, and phosphorus, the first two consti- 

 tuting the bulk of the alloy, and being united in 

 their chemical equivalents as a true alloy. This 

 solder can be used before the blowpipe or with 

 a soldering iron. In the former case a little sil- 

 ver can be added to it without making it too 

 hard to melt, and giving it a better color. For 

 use with the copper bit this solder leaves little 

 to be desired. 



A curious by-product in the manufacture of 

 aluminum and the reduction of refractory ores is 

 carbide of calcium, from which, wet, acetylene is 

 readily obtained ; and acetylene is an illuminant 

 of high candle power, the chief bar to using 

 which has been its cost. 



Aluminum and antimony, according to Roche, 

 combine easily in all proportions. Alloys with 

 less than 5 per cent, antimony are harder and 

 more elastic than pure aluminum, of silver- 

 white color, lustrous, and unaffected by atmos- 

 pheric influences. 



Copper and Tin. The superior affinity of 

 oxygen and sulphur for each other to that of 

 either for the metal with which it may be com- 

 bined, which has been utilized for years in the 

 metallurgy of lead, has been successfully ap- 

 plied, under an invention of Messrs. James and 

 Nichols, to the reduction of copper. The appli- 

 cation of the principle is made in this manufac- 

 ture when the white-metal stage has been reached 

 in the ordinary Swansen method of working. 

 The desired reaction is similar to that with the 

 lead compounds. Mr. Claude Vantine estimates 

 that a saving of 2 13s. Gd. per ton may be real- 

 ized in the cost of production of ingot copper 

 by this "direct" method, as he terms it. 



For coating sheet steel with copper, W. B. 

 Hollingshead deposits copper electrically and 

 then rolls the sheet. Upon this he deposits a 

 second coat of copper and rolls it again, or 

 works it under a planishing hammer. The in- 

 ventor aims to overcome by his method the 

 drawbacks incidental to the crystalline and loose 

 nature of electrically deposited coats of copper. 



For recovering tin from tin-plate articles, C. 

 W. Kriens and J. R. Harper, of London, employ 

 iron tanks filled with a solution, of caustic alkali, 

 into which the tin waste is thrown. This is used 

 either hot or cold. When sufficiently saturated, 

 the solution is evaporated to such a degree that 

 the tin is held partly as a soluble salt with the 

 alkali and partly as oxide. The dry material is 

 then calcined for the purpose of converting the 

 soluble salt into insoluble oxide of tin; the ma- 

 terial is then ground and the alkali is washed 

 out, leaving the insoluble oxide of tin as residue. 

 The alkali, carbonized in the operation, is after- 

 ward causticized in the usual way, and recovered 

 for future use, while the iron is not injuriously 

 affected. Thus all the material is saved. 



In the process of W. and J. Williams and R, 

 Harries for cleaning tin and tern plates, the 

 plates, after passing through the bran trough, 

 are fed to a pair of rolls coated with India rub- 

 ber, gutta-percha, vulcanite, or like substance, 

 rotated at the same speed, by which each plate 

 is fed to a pair of sheepskin-covered rolls rotat- 

 ing at a higher speed. In its passage between 

 these rolls a part of both faces of the plate is 

 cleaned. The plate is then sent to a second pair 

 of feed rolls, whence it is passed to a second 

 pair of sheepskin-covered rolls, where the pro- 

 cess is completed. 



A method has been invented in Germany for 

 coating cotton with tin. A paste of commercial 

 zinc powder and white of eggs is brushed on to 

 the cotton. Upon drying it the albumen coagu- 

 lates. The cotton is then placed in a bath con- 

 taining perchloride of tin, when the tin is de- 

 posited on the cotton, which is afterward calen- 

 dered, rinsed, and dried. 



Lead and Zinc. In the lead process of A. 

 MacDonald, galena, or lead sulphide, is melted 

 and treated by exposing it to a current of air, 

 whereby a large portion is driven away as sul- 

 phate-of-lead fumes, while the rest is left as 

 metallic lead, and may be run off to form pigs, 

 or, by continuing the blowing, be converted into 

 lead oxide or litharge. Lead ore generally con- 

 taining a proportion of silver, not all the lead 

 should be converted into litharge, but a part of 

 it should be retained to be treated for that metal. 

 The lead oxide produced may be run off to cool, 

 or fresh charges of galena may be added to it 

 and the whole con verted into lead and sulphurous 

 acid; and the sulphate obtained in Ihe first step 

 of the process may be similarly treated, or it may 

 be added to the hot lead in the converter to pro- 

 duce galena. Again, when in the first stage the 

 sulphate-of-lead fumes cease, or nearly cease, to 

 be evolved, sulphur may be added to the lead in 

 the converter, with continued blowing to produce 

 fresh sulphate: and thus, by alternately addii-g 

 sulphur and blowing, the whole of the galena. 

 can be converted into lead sulphate. At any 

 stage galena may be added and the blowing con- 

 tinued; and thus, by successive repetitions of 





