METALLURGY. 



471 



in the casting. With a view to remedying these 

 defects, in a process patented by E. Taussig, the 

 metal is subjected in the mold, after the comple- 

 tion of the casting, to renewed melting, the gases 

 generated being sucked off at the same time, in- 

 asmuch as the casting takes place in a vacuum, 

 and the cast metal is exposed to the action of an 

 electric current the strength of which is such 

 that it will keep the metal at the melting 

 point. 



Herr Krieg, of Magdeburg, has brought out a 

 process for manufacturing pure tin plate com- 

 mercially. He first forms the chloride of the 

 metal ; it is then oxidized, and the oxide is re- 

 duced by means of an electric arc. 



In the process of C. G-. Kichardson and A. B. 

 English for treating ores containing nickel, cop- 

 per, or nickel and copper combined with sulphur, 

 the ores are subjected, in conjunction with sul- 

 phate of calcium and silica, or a suitable silicate, 

 to the action of heat until fused, whereby the 

 sulphur of the sulphide of iron is oxidized and 

 is driven off, the iron oxidized, and the nickel, 

 or copper, or nickel and copper, freed therefrom 

 in the form of a sulphide or sulphides. 



In a new process for obtaining zinc from its 

 complicated ores, the ore is first roasted to free 

 it from arsenic and sulphur; it is then mixed 

 with carbonaceous matter and heated in a fur- 

 nace. The fumes given off are dissolved in 

 sulphuric acid, the lead being precipitated as a 

 sulphate, while the zinc is obtained from the 

 liquid by electrolysis. 



A method for recovering the minerals that 

 pass away in smoke and fumes among which 

 are gold, silver, and lead is to be tried at the 

 smelting works in Omaha and Denver. The ap- 

 paratus consists of a horizontal flue some 1,500 

 feet in length, exposing a surface for radiation 

 and condensation of the heated gases of 54,000 

 square feet. The fumes are drawn through this 

 flue by means of a fan, which at full speed re- 

 volves at a velocity of nearly two miles a minute. 

 They then pass into a spacious building, from 

 which they can not escape except through a filter 

 of textile fabric. The colorless gas passes away, 

 and the valuable sort is retained in a condensed 

 form on the inner side, from which it is collected, 

 compressed into molds, and fed back again into 

 the furnaces, where the valuable metals are ex- 

 tracted and separated. 



An apparatus for discovering internal flaws in 

 steel, invented by Capt. De Place, of Paris, con- 

 sists of a small pneumatic tapper worked by the 

 hand, with which the sample of steel or iron is 

 tapped all over. With the tapper is connected a 

 telephone with a microphone interposed in the 

 circuit. One operator is required to apply the 

 tapper and another to listen through the tele- 

 phone to the sounds produced. Both are in elec- 

 trical communication and in separate apartments, 

 so that the direct sounds of the tap may not in- 

 terrupt the listener, whose duty it is to detect 

 flaws. In applying the system, one operator 

 places the telephone to his ear, and while the 

 sounds produced by the taps are normal he does 

 nothing. Directly' a false sound, which is dis- 

 tinguishable from a normal sound, is heard, he 

 signals for the spot to be marked, and by this 

 means is able both to detect the flaw and fix its 

 locality. 



Apparatus. An apparatus is described by 

 A. L. Eltenhead as erected by him for an electro"- 

 chemical process with gold and silver a process, 

 the author claims, which overcomes the difficul- 

 ties encountered in precipitation in the cyanide 

 process, while the resultant precipitate is recov- 

 ered in the shape of amalgam. The ore. ground 

 to proper fineness, is leached by passing over it 

 a solution of cyanide of potassium, followed by a 

 second solution of less strength. The pulp' is 

 afterward washed in clean water and drained. 

 All the solutions from the leaching vats are 

 saved and passed over a precipitating box of 

 novel construction. For this process many ad- 

 vantages are claimed over other cyanide meth- 

 ods, among which may be mentioned its cleanli- 

 ness, quickness of action, and cheapness. 



An apparatus invented by A. Sattmann and 

 A. Homatsch, of Austria-Hungary, is designed 

 to enable fuel of inferior quality and liquid or 

 gaseous fuel to be utilized in the production 

 of crude iron by means of furnaces of special 

 construction, and also to effect the fining in a 

 more efficient manner than by the fining process 

 usually carried out in reverberatory furnaces. 

 The crude iron is brought into immediate con- 

 tact with gas jets, whereby the fining operation 

 is accelerated and the consumption of fuel is 

 reduced. 



An improvement lately placed on the water- 

 jacket furnaces of a copper company in Arizona 

 consists of an arrangement for heating the blast 

 before it enters the furnace. A wind-jacket, 

 connected with the blast supply pipe and with 

 the regular wind-box, surrounds the crucible of 

 the furnace. The blast from the supply pipe 

 enters the wind-jacket in its usual cool condi- 

 tion, slightly higher than the surrounding at- 

 mosphere, and passes around the crucible, where 

 it comes in contact throughout its passage with 

 the hottest part of the furnace. It then flows into 

 the regular wind-bag and thence to the tuyeres. 

 In making the passage around the crucible it 

 serves several purposes : it heats the blast to a 

 high degree by taking up the heat formerly lost 

 to a large extent by radiation, keeps the cruci- 

 ble from getting abnormally hot, and makes it 

 cooler and more comfortable for the men work- 

 ing near the furnace. 



The method of Hermann Thofehm for the 

 electro-deposition of metals is intended to pro- 

 vide apparatus whereby electrotypic depositions 

 of copper or other metal can be obtained in such 

 a way that the metal deposited shall be very fine 

 and homogeneous. It consists essentially in the 

 combination of an electrolytic bath, of an anode 

 and cathode, and of a reciprocating spraying 

 apparatus for showering the electrolyte upon the 

 anode. 



In a paper read at the Iron and Steel Insti- 

 tute on the capacity and form of blast furnaces, 

 William Hawdon observed that in Cleveland 

 during recent years the content has risen from 

 about 6,000 cubic feet to as much as 30,000 cubic 

 feet, with the result of increased economy and 

 larger output. The author pointed out that the 

 crucible or wall of the furnace that is, the part 

 immediately above the hearth has its diameter 

 governed by two considerations : if it be too 

 large, a pillar of perfectly cold material may be 

 formed in the center of the mass of ore, fuel, 



