MECHANICS A-ND USEFUL ARTS. 77 



drogen coml^ines with and removes the sulpliur, phosphoi-us, and 

 other metalloids which render the steel brittle. When the color 

 of the tlarae at the top of the mass indicates a proj^er amount of 

 decarburation, the sLeel is run out. He operates either in a cupola 

 or a reverberatoiy furnace of his own construction, in which the 

 waste heat from the furnace is utilized to produce the steam. 

 There has always been a difficulty in knowing when to stop the 

 decarburating current, the process often being carried too far ; 

 but this author says common steel can always be regularl}^ pro- 

 duced by completely decarburating the cast-iron and then adding 

 ten per cent, of spathic cast-iron, which restores to the iron the 

 amount of carbon necessary to effect the conversion into steel. 

 By a peculiar contrivance, the author shuts off the current of su- 

 jjerheated steam from the metal and jaasses it into the chimney, 

 where it serves to increase the draft, and thus leaves the steel iu 

 a state of tranquil fusion for about fifteen minutes, by which he 

 gets a perfectly homogeneous mass. To remove bubbles in his 

 castings he has a very ingenious device. A cannon, for example, 

 being cast, while the inetal is still hot and soft, he covers the mould 

 hermetically with a sort of hat, from the top of which rises a pipe, 

 in which is placed six or ten grammes of a mixture of eighty parts 

 of saltpetre and twenty jjarts of charcoal. By opening a stop- 

 cock the powder is allowed to fall on the metal, where it gets 

 ignited, producing a large quantity of gas which exerts pressure 

 on all parts of the casting, removing the bubbles and increasing 

 the tenacity of the metal. 



HARD AKD TUNGSTEN IRON. 



M. Gaudin reports, that while experimenting in an ordinary 

 cupola furnace, by melting iron at a very high temperature with 

 phosphate of iron and peroxide of manganese, he succeeded in 

 obtaining a species of iron, very hard and forgeable, but turning 

 well, and applicable to the manufacture of jjieces which require 

 great strength and hardness. The metal is remarkably sonorous, 

 and might perhaps be applied to the casting of bells. A still 

 harder metal may be produced by the addition of tungsten to 

 ordinary cast-iron ; this tungsten-iron is said to surpass evisry- 

 thing previously known as a material for cutting rocks, and that 

 crystals of it will cut glass as easily as the diamond. — Jour. 

 Soc. Arts, No. 685, 1866. 



SEPARATING PHOSPHORUS FROM METALS. 



It is well known that phosphorus is a substance which prevents 

 the production of pure quahties of iron and other metals, and all 

 attempts to remove the same have hitherto tailed. Mr. Carl H. 

 L. Wintzer, of Hanover, has found that chlorine gas and chloride 

 of calcium are adapted to obtain the desired result. Chlorine 

 gas, as a simple element, does not decompose, and chloride of 

 calcium is the only combination thereof, wliich, at the different 

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