M. TECHNOLOGY. 511 



covered crucible, then add 25 parts of Silesian zinc, purified 

 by sulphur ; mix thoroughly by stirring, and pour into sand 

 moulds. 34 C, 1874, vil, 53. 



TINNING IRON WIRE. 



Dr. Heeren recommends the following process as rendering 

 iron wire silvery white, and as adapted to wire already in 

 spirals and other forms of iron, and therefore preferable to 

 tinning by the aid of heat : First dip the wire in hydrochloric 

 acid with a piece of zinc in it, and then place it, for about 

 two hours, attached to a zinc plate, in a bath of two parts of 

 tartaric acid dissolved in 100 parts of water, with the addi- 

 tion of three parts of tin salt and three parts of carbonate of 

 soda. On removal from this bath it must be brightened by 

 polishing or drawing. 6 C, May 7, 1874, 188. 



JAPANESE BRONZE. 



Curious ornamental bronzes are produced in Japan, which 

 much resemble slate when in thin plates, and these are cov- 

 ered with elaborate designs in silver possessing a bright pol- 

 ish, giving to the work a very striking and elegant appear- 

 ance. This alloy has recently been examined by M. Morin, 

 who finds that it contains, in addition to copper, from four to 

 five per cent, of tin, and, on an average, ten per cent, of lead. 

 This combination is easily moulded into thin plates, which 

 are varnished, and through this covering the designs are then 

 scratched with a suitable instrument. The plate thus pre- 

 pared is then plunged into a silver-bath, when the silver is 

 gradually deposited on the unprotected portions. Finally, 

 it is placed in a muffle furnace, where the copper is blackened 

 by oxidation, while the silver retains its brightness. 



ALLOY RESEMBLING STEEL. 



An alloy, with the properties of steel, may be formed, ac- 

 cording to a French patent, by fusing together iron, tungsten, 

 and nickel, in a crucible, by the aid of a flux prepared by 

 melting together 36 parts of boracic acid, 32 of calcined 

 quartz, and 32 of carbonate of lime. For the first quality of 

 alloy, 93 per cent, of soft iron, 6-J of tungsten, and \ of nickel 

 are employed ; for the second quality, 95 per cent, of soft 

 iron, 4-^ of tungsten, and \ of nickel ; for the third quality, 97 



