470 



METALLURGY. 



ably hardened. It is exceeded in malleability 

 only by gold and silver, ranks after copper in 

 ductility, and takes and retains a high polish. 



An alloy of aluminum and tungsten is now 

 used in the manufacture of cycles. It is only 

 slightly heavier than aluminum, and has a spe- 

 cific resistance like mild steel. It can be forged, 

 either hot or cold, andeasily machined. 



A new alloy, composed of steel, copper, and 

 aluminum, is made by melting iron or steel, and 

 adding to the molten metal aluminum and cop- 

 per in quantity less than that of the steel. This 

 alloy is very hard, and is suitable for cutting 

 tools. 



An alloy of copper, zinc, and aluminum, pat- 

 ented by D. W. Sugg, is composed, in the lowest 

 grade useful for mechanical purposes, of 50 parts 

 of copper, 40 parts of zinc, and aluminum in the 

 proportion of 2i- per cent, of the whole. The 

 alloy may be made richer by using other propor- 

 tions of copper and zinc, while the proportion of 

 aluminum remains the same. The mode of 

 preparation varies according to the nature of 

 the alloy required. If a hard metal is desired 

 the copper and aluminum are mixed first and 

 the zinc is added in small pieces to the molten 

 muss continuously agitated. The resulting red 

 alloy will be susceptible of a high polish. To 

 produce a ductile metal the zinc and aluminum 

 are mixed and the copper is added afterward. 

 The resulting alloy will have the appearance of 

 brass. In both cases a nonoxidizable metal is 

 obtained, proof against the action of sea water 

 and partially proof against acids. 



"Stredura" is the name of a new antifriction 

 bearing metal for mechanical use. It is malle- 

 able, and can be cast in any form. Of four 

 alloys offered, No. 1 is recommended as especially 

 adapted for bolts, studs, propellers, and propel- 

 ler blades (not being subject to the action of 

 corrosion or pitting, etc.), anchors, chains, rud- 

 ders, propeller shafts and bolts, etc. No. 2 is 

 principally adapted for shaft and other bearings 

 in marine and other engines, more particularly 

 where they are exposed to the action of water or 

 weather; also for valves, pumps, and pump rods, 

 etc. No. 3 is harder than JNos. 1 and 2, and is 

 used mainly for sleeves, for propeller shafts, 

 bushes in stern tubes, cylinder faces for slide 

 valves, piston rings and piston valves, shoes on 

 crossheads, etc. No. 4 is a white metal for all 

 antifriction purposes, such as liners for general 

 bearings, thrust blocks and crossheads. propeller 

 and main shaft bearings, and general usages re- 

 quiring such metal, and resists all action from 

 sea water. 



Among specimens of apparatus of platinum 

 and platiniferous alloys exhibited by Johnson, 

 Matthey & Co., were some stills for concentrat- 

 ing sulphuric acid, the interiors of which were 

 lined with a gold alloy containing 5 per cent, of 

 platinum. The combination resists the action 

 of the impure acid much longer than gold or 

 platinum alone, and materially increases the life 

 of the pan. The iridioplatinum used in making 

 the international standard metre and kilogramme 

 contains 90 per cent, of platinum and 10 percent, 

 of iridium. 



The presence in aluminum bronze of a very 

 small admixture of boron has been found by H. 

 N. Warren to contribute to the production of a 



denser and more durable alloy. The aluminum- 

 boron bronze casts and smelts well, and is free 

 from some drawbacks encountered in working 

 with the ordinary aluminum bronze. The alloy 

 forms at a lower temperature than pure alumin- 

 um bronze. 



New Processes. The process of C. Raleigh 

 for the treatment of slimes, or ore in a state of 

 fine subdivision, containing precious metals, I lie 

 extraction of which is about to be effected with 

 the aid of chlorine, cyanide of potassium, or 

 other lixiviating or leaching solution, consists in 

 keeping the mass of slimes or tailings in a state 

 of vibratory or pulsatory movement. Such 

 movement .may be imparted by means of water, 

 air, or gas, pumped and forced into and out of t he 

 vat or filter in such a way that thorough circula- 

 tion takes place. The leaching solution may take 

 the place of the water jet, and oxygen gas may 

 be used with advantage to accelerate the solvent 

 action on the gold and silver. Muddy water 

 may be used, or mud added, to increase the 

 density of the leaching solution and prevent the 

 settling or packing of the ore. 



In the process of J. B. Oochrane and T. II. 

 Taylor the removal of sulphur from iron is ef- 

 fecteJ by treating the metal with a compound or 

 mixture of fluorspar, lime or limestone, and iron 

 or steel scrap, with a little salamrnoniac to bind 

 the other ingredients together. The substances 

 are used in such proportions that by merely run- 

 ning the molten metal upon the compound, and 

 allowing it to rise with the metal, the sulphur is 

 to a very great extent removed. If it be desired 

 to remove silicon with the sulphur, oxide of iron 

 is employed in the form of iron ore or otherwise, 

 in lieu of or together with the iron turnings or 

 borings. The time required for this process is 

 only that occupied in filling the ladle with molten 

 metal from the cupola. 



By the process of Thomas Hampton, compound 

 steel armor is economically and readily produced, 

 with an exceedingly hard and impenetrable front. 

 The middle or internal part is made of soft steel, 

 while the back of the plate consists of a semi- 

 high carbon steel of great toughness, which will 

 entirely prevent cracks or fissures in that part, 

 and likewise impart additional resistance- to 

 penetration, after the hard front has performed 

 its duty. The novelty and value of the invention 

 chiefly consist in the construction and operation 

 ol the ingot mold, by which means a compk 

 union, or weld, of the several qualities of steel 

 effected, and also in the use of steel alloys, which 

 are employed in the construction of the ingots. 



In the process of Prof. Neesen for platim 

 aluminum, the metal is first dipped in a soluiio 

 of caustic potash or soda, or in muriatic aci< 

 until bubbles of gas begin to appear, then int 

 corrosive sublimate, then a second time into tl 

 caustic or acid, and finally in a solution of a sal 

 of the coating metal. A film of the metal is 

 rapidly formed, and adheres so firmly that, in 

 the case of gold, silver, or copper, the plate may 

 be rolled out or polished. 



The more or less rapid cooling of metals after 

 melting has a considerable effect upon the plr-s- 

 ical condition and more especially upon the den- 

 sity and strength of the casting. Gases are often 

 generated at the beginning of the cooling, and 

 aid in the formation of flaws and of cavities 



