446 



METALLURGY. 



forward in horizontal drawing tubes. Here the 

 metal tube is drawn through successively decreas- 

 ing dies, over correspondingly decreasing man- 

 drels, the metal being at the same time evenly 

 and uniformly thinned down by the mechanical 

 operation, the particles following a gradual and 

 regular flow. After each pass the tubes are sub- 

 mitted to the annealing process, as in the case of 

 the vertical presses. 



The principal feature of the nonoxidizing pro- 

 cess for annealing steel of H. K. Jones, of Hart- 

 ford, Conn., consists in keeping the retort in 

 communication with the gas holder or gas main 

 during the entire process of heating and cooling, 

 the gas thus being allowed to expand back into 

 the main, and being therefore kept at a practi- 

 cally constant pressure. The process has been in 

 constant use for two or three years, while several 

 tons of metal have been annealed and turned 

 from the retorts daily, bright, and at a very 

 slight expense. The gas was taken directly from 

 the mains supplying the city with illuminating 

 gas. It has been the practice also to reanneal 

 by this process all of the tool steel used in a large 

 machine shop, although it had already been an- 

 nealed at the steel works where it was made, 

 and the slight additional expense was more than 

 compensated for by the ease with which the steel 

 was worked, and by the saving in the wear of cut- 

 ting tools. It was also noticed that if metal that 

 had been blued or slightly oxidized was subjected 

 to the annealing process, it came out bright, the 

 oxide having been reduced by the action of the 

 gas. 



A process devised by MM. Walrand and Lege- 

 nisel for the manufacture in converters of small 

 dimensions of steel suitable for castings and in- 

 gots is intended to remedy the final failure of 

 temperature, rendering casting difficult, that 

 occurs in ordinary attempts to produce steel in 

 small masses. Its principal feature is the addi- 

 tion of a small quantity of smelted ferro-silicon 

 containing 10 per cent, of silicon at the moment 

 when the Bessemer operation is completed ; after 

 which the blast is continued up to the moment 

 determined by the operator. The addition is 

 followed by a great rise of temperature. 



In the aluminum process, partly chemical and 

 partly electrical, of William Frishnuth, the alu- 

 minum oxide is extracted from clay and dis- 

 solved. The solution is then exposed to the 

 electric current, which causes the pure metal to 

 be thrown down on brass plates. From these it 

 is removed by a simple but ingenious chemical 

 process in a state of almost perfect purity, and in 

 the form of a silvery impalpable powder. It only 

 remains to smelt it into ingots. It is claimed 

 that by this process aluminum can be extracted 

 at a price much below the present market value, 

 and in any desired quantity. The by-product or 

 residue of the treatment is a valuable fertilizer. 



The chief feature in an improved apparatu- 

 for smelting and casting by Herr Eduard Tauss 

 sig is the conducting of the operation in a par- 

 tial vacuum. The smelting furnace is connected 

 with the casting apparatus and the mold so that 

 they form an air-tight inclosed whole, the sepa- 

 rate parts of which are easy of access. The smelt- 

 ing is effected by electricity. The current is 

 conducted through the metal" to be melted, which 

 is used in a granular state, by means of elec- 



trodes made of the same metal, or of a more 

 refractory one. 



Miscellaneous. In cleaning mercury at the 

 Physikalischtechnische Reichsanstalt, in Berlin, 

 the raw material is filtered and dried, and twice 

 distilled in a vacuum to get rid of the heavy 

 metals. The electro-positive metals, such as zinc 

 and the alkali metals, are separated by electroly- 

 sis. The mercury is precipitated from a solution 

 of mercurous nitrate obtained by the action of 

 nitric acid on excess of mercury. The solution, 

 together with the impure mercury acting as an 

 anode, is contained in an outside glass vessel, 

 into which a current from a Giilcher thermopile 

 is conducted by an insulated platinum rod. The 

 cathode rod dips into an interior shallow glass 

 vessel, in which the pure mercury is collected. 

 The mercury thus obtained is fit tor use in stand- 

 ard barometers and resistances. 



M. Placet has succeeded in preparing consid- 

 erable quantities of chromium by electrolysis, 

 under such conditions as make commercial pro- 

 duction possible. His chromium contains 99 per 

 cent, of the metal, and is therefore of greater 

 purity than that prepared by reduction with 

 carbon, which contains a considerable proportion 

 of that element. The industrial use of chromi- 

 um is, according to M. Moissan, susceptible of 

 becoming very extensive on account of the un- 

 alterable character which it communicates to the 

 surfaces on which it is deposited. It is much 

 superior to nickel for this purpose. 



Titanium is found, often in large quantities, 

 in many iron ores. It is difficult to reduce, and 

 the largest part of it in the ore goes to the cinder 

 in the blast furnace, and gives the slag a dark 

 and sometimes black color, while it is very 

 difficult to find even a trace of it in the iron 

 produced. Titanates being difficult to reduce, 

 metallic titanium renders the smelting of the 

 iron difficult. It is believed, however, that the 

 presence of titaniferous ores is favorable to the 

 formation of spiegeleisen. Certain tests made 

 by Clason with pig iron indicate that titanium 

 favors the tendency of iron to combine with 

 carbon. If this is really a case of cause and 

 effect, the action of the titanium must be very 

 strong, because in the different samples of pig 

 iron produced by this method no traces of 

 titanium were found. By the fusion of 99 per 

 cent, of steel and 1 per cent, of metallic tita- 

 nium. Karsten obtained an exceedingly good steel, 

 of which the tenure in titanium varied greatly, 

 and he discovered in this circumstance another 

 proof that iron and titanium in the metallic 

 state do not enter into a combination, but are 

 only mechanically mixed. From these and other 

 facts mentioned by Mr. J. B. Nau in his paper 

 on the subject, the conclusion may be drawn 

 that if titanium has any notable advantage in 

 the production of steel, its influence on the 

 qualities of iron must be so powerful that even 

 small amounts hardly detected by analysis make 

 themselves felt; or that the influence of tita- 

 nium is indirect, consisting in the elimination 

 of some obnoxious elements from the steel. 



In estimating the temperature developed in 

 various industrial processes, M. Chatelier takes 

 as points of comparison the melting points deter- 

 mined by M. Violle, viz., sulphur, 448 C. ; gold, 

 1,045 C. ; palladium, 1,500 C. ; platinum, 1,- 



