532 CURRENT ToPics .

Blau Water Gas for Industrial Purposes. A. MEADE. (J. Gas Lighting, cxvii, 83 . ) - -The industrial use of water gas has made considerable progress on the continent of Europe. Its most impor- tant property is its very high flame temperature. With preheated air, a temperature above the melting-point of platinum is reached, and under ordinary conditions the hottest part of the flame is be- tween 28oo ° and 3ooo ° F. Burned at a pressure of ~ pound per square inch, with air at 2 ~ pounds, in a fire clay faced burner, it is used for pipe welding. For heating purposes it is unnecessary to purify it from hydrogen sulphide, but this must be done for lighting and. power purposes. Blau water gas is not very suitable for gas engines, as it contains so much hydrogen that it cannot be highly compressed. With suitable appliances the results obtained for in- candescence lighting are equal or superior to those obtained with ordinary coal gas. It is also used for the preparation of hydrogen by liquefying or freezing out the other constituents, and bv cement manufacturers to heat their rotary furnaces.

Design of Thirty-Ton Induction Furnace. A. HIORTH. (/Jmer. Electrochem. Soc. Trans., xx, 293 . ) - -F rom experiments with his 5-ton monophase furnace at Jossingfjord, the resistance of the furnace and the bath is estimated. The liquid iron seems to have a resistance of 1.4 ohms per square ram. per metre in length; higher estimates, up to 1.7 ohms, are probably more correct. The power factor was o.81 with a charge of 3 tons, 0.73 with 4, 0.65 with 5, and 0.6 with a charge of 6 tons. The 3o-ton furnace is to be 3-phase. With 12. 5 cycles, cos ~r, would be o.34; with IO cycles, o.41; with 8 cycles, 0.5; with 5 cycles, 0.67 . He decides upon 8 cycles and one generator yielding 3,540 ampfres at 230 volts, and occasionally up to 4,300 amp6res. Unger thought that several smaller generators would be preferable to one large unit at the low periodicity.

Reduction of Power Consumption in Electric Steel Furnaces. DR. C. HERING. (Metal. and Chem. Engin., ix, 59o . ) - -On the basis of Hiorth 's figures (see preceding note) and those supplied by R6chling-Rodenhauser, Dr. Hering calculates the electric energy which should suffice to keep the temperature of the fused steel constant. This energy would be 26 k.w. per ton for steel furnaces of a capacity of 0.5 ton, 9.5 k.w. for Io-ton furnaces, and 5.5 k.w. per ton of steel for 5o-ton furnaces. These figures should be realized with suitable construction.

Increasing the Ductilily of Tungsten. (Brass World, viii, 3, IO5.)--Metallic tungsten is now used to such an extent in electric lamps that any method of improving its quality becomes valuable. Werner yon Bolton, of Charlottenburg, Germany, the inventor of the tantalum electric lamp, has patented a method of increasing the