'484 



METALLURGY. 



the furnace below, passes through the clippings. 

 The tin is attacked and stannic chloride is formed, 

 which volatilizes, and is subsequently collected 

 upon condensing surfaces moistened with a solu- 

 tion of the same chloride. The iron is not at- 

 tacked, and when entirely cleaned from tin is 

 removed from below, and again used. 



A method has been invented in Germany of 

 covering tissues of cotton yarn with a flexible 

 and brilliant deposit of tin. A clear paste of 

 commercial zinc powder and white of eggs is first 

 spread on the textures with a brush. The coat- 

 ing coagulates in drying. The tissue is then 

 placed in a bath of perchloride of tin, and that 

 metal is precipitated on the zinc. The article, 

 after rinsing and drying, is calendered, where- 

 by a luster is imparted to the tin. 



Lead. In a paper read before the Eoyal So- 

 ciety, J. B. Hannay said that the metallurgy of 

 iron had obtained complete elucidation during 

 the last twenty years, and that of copper was 

 pretty well known, while the chemists of the 

 mint, notably Roberts-Austen, had made the 

 metallurgy of the precious metals their special 

 study ; but the fourth great domain of metal- 

 lurgy, that of lead, was still in the empirical 

 stage. Mr. Hannay proceeded to describe sev- 

 eral new volatile compounds of lead, the discov- 

 ery of which, he said, gave the key to the solution 

 of many of the difficulties which had hitherto 

 beset the investigator. One process consisted in 

 passing a stream of air through the lead ore in 

 a Bessemer converter, by which means all the 

 ore was converted into pig lead, or litharge, or 

 sulphate of lead, as might be required. The oxi- 

 dation of the ore supplied all the heat required 

 to conduct the process, so that no fuel was need- 

 ed. The importance of this process, Mr. Han- 

 nay affirmed, might be judged from the fact 

 that, besides obtaining all the lead as finished 

 product without loss, against a 20-per-cent. loss 

 by the old method, every ounce of silver was col- 

 lected and separated without expense, no matter 

 how little of that metal might be present. 



As to whether pure or alloyed lead is best able 

 to withstand the attacks of sulphuric acid, Dr. 

 Lunge, after experimenting with various alloys, 

 concludes that : 1. There is no difference in the 

 cold between the actions of sulphuric acid on 

 pure and antimonial lead, when the admixture 

 of antimony does not exceed O2 per cent. ; a lead 

 of the following composition Sb T81 per cent., 

 Cu - 05 per cent., Bi O'Ol per cent., Fe O'Ol per 

 cent., Sn 0'04 per cent., As O'lO per cent. was 

 more strongly attacked than pure lead, in contrast 

 to the general supposition that antimonial lead is 

 better able to withstand the attacks of sulphuric 

 acid ; when the acid is warm, the difference in fa- 

 vor of pure lead is more marked. 2. The action of 

 nitrous vitriol is in all cases stronger when air 

 has access than when not, and is always greater 

 than that of pure vitriol. 3. The addition of a 

 small percentage of copper to the lead does not 

 increase its power to resist the attacks of sulphu- 

 ric acid when the temperature is below 200 C. ; 

 when the temperature is above 200 C. the ad- 

 dition of O'l to 0'2 per cent, of copper is advis- 

 able, though its effect is not very marked. 



The Roessler-Edelmann process of lead de- 

 silverization consists of two parts desilveriz- 

 ing the lead by means of an alloy of zinc and 



about 0-5 per cent, aluminium, from which re- 

 sults refined lead on the one hand, and a homo- 

 geneous zinc-silver alloy on the other, and 

 working up the zinc-silver alloy to refined silver 

 and refined zinc. Simplicity and saving of time, 

 labor, and material are claimed for it. 



Nickel. In a series of experiments in casting 

 and forging nickel at Altona, under the direc- 

 tion of a German industrial society, it came out 

 that pure nickel without addition of magnesium 

 was porous and irregular in fracture which 

 was yellowish gray and would not forge well ; 

 that for the production of a useful nickel the 

 addition of some magnesium is necessary ; and 

 that aluminum can not replace the magnesium. 



In C. C. Bartlett's method for separating 

 nickel, primarily in the form of a sulphate, from 

 copper contained in certain nickeliferous copper 

 ores, the ores or mattes are mixed with ordinary 

 niter cake, the salt cake of commerce, or certain 

 other materials, and are smelted, with the pro- 

 duction of a very fluid matter of very low spe- 

 cific gravity. This matter includes the copper 

 contained in the ore, while the nickel will re- 

 main in a mass by itself, and, being of greater 

 specific gravity, will settle, after tapping the 

 furnace, in the bottom of any vessel in which 

 the mass is collected. The portion which sinks 

 to the bottom will be found to consist ordinarily 

 of sulphate of nickel, perhaps, with the salts of 

 nickel, while the copper, iron, or other metal 

 will be converted into sulphides, and rise to the 

 top. When cool, the mass is broken up and the 

 layers are separated by hand. 



Manganese. Test experiments have been 

 made by Prof. Lorenz, of GOttingen, and his 

 colleagues to determine whether manganese is 

 really volatile or the volatility it manifests in 

 furnace working is due to the intermediate action 

 of carbon monoxide derived from the carbon 

 usually present, forming a volatile and dissocia- 

 ble compound of a nature similar to nickel 

 and iron carbonyl. It was definitely proved 

 that carbon monoxide does not combine with 

 manganese at a temperature below 850 C. In 

 the high-temperature experiments with carbon 

 monoxide a large quantity of manganese was 

 found to have volatilized and condensed again. 

 Hence manganese is certainly volatile with car- 

 bon monoxide. It was afterward found that 

 equally good deposits of manganese dust were 

 obtained when a current of either hydrogen or 

 nitrogen, neither of which combines with man- 

 ganese, was employed. It therefore appears that 

 volatility is a property of the metal itself, and 

 not merely attendant upon the formation of a 

 compound with carbon monoxide, and is singu- 

 larly manifested even at the temperature of the 

 melting point. 



For manufacturing, on a commercial scale, 

 metallic manganese containing a minimum of 

 detrimental impurities and absolutely free from 

 carbon, W. H. Greene and W. II. Wahl expose 

 the pulverized manganese ore purified from iron, 

 or containing less than 1 per cent, iron, to re- 

 ducing gases at a temperature approximating 

 redness. All the manganese is thus converted 

 into greenish-gray manganese monoxide, which 

 must be allowed to cool out of contact with air, 

 in order to prevent oxidation to red manganaso- 

 manganic oxide. The monoxide is then mixed 



