M. TECHNOLOGY. 529 



by an elastic belt, and directed by means of the handles of 

 its axis. A ring of steel, the outer edge of which is cut more 

 or less finely, according to the purpose, serves as the file 

 proper, and is fastened upon the rim of the cast-iron disk, 

 from which it derives a rapid rotary motion, while it is di- 

 rected by means of the handles, the elastic belt allowing the 

 necessary play. 5 (7, xxv., 1872, 198. 



BLEACHING WITH SULPHUROUS ACID. 



In bleaching woolen goods with sulphurous acid, Mr. Bas- 

 taert proposes, as an essential improvement, to burn the sul- 

 phur upon a separate hearth, so as to conduct the vapor up- 

 wards, and then drive it, mixed with steam, through a hori- 

 zontal tube into the chamber. If the goods are on rollers the 

 action may be kept up continuously. There should, however, 

 never be more steam than is necessary for carrying the sul- 

 phurous gas along, as its condensation in the chamber would 

 be injurious. It has also been suggested to make the chamber 

 itself of plate-glass, so that the action of light may be added 

 to that of the sulphur. 5 (7, 1872, 207. 



PLATINUM-BRONZE, A NEW ALLOY FOR COOKING UTENSILS. 



It is proposed to manufacture cooking utensils out of a 

 new and entirely unoxidizable alloy (bearing the name of 

 platinum-bronze), as a substitute for the ordinary copper al- 

 loys, so readily acted upon by acids, and consequently in- 

 volving so much danger in their use. The bronze is prepared 

 from nickel, made thoroughly pure by various processes, and 

 by maceration in concentrated nitric acid. The proportions 

 employed are 100 parts of nickel, 10 of tin, and 1 of platinum; 

 the latter two metals being added to the fused nickel in the 

 proportion of 4 of tin to 1 of platinum, and the remaining 6 

 parts of tin added subsequently. For bells and sonorous ar- 

 ticles the proportions are slightly varied, viz., nickel, 100 

 parts ; tin, 20 ; silver, 2 ; and platinum, 1. 3 A, August, 83. 



COATING ZINC WITH IROX. 



Zinc may, it is said, be coated with a brilliant and solid 

 layer of iron by means of the following process. A solution 

 is made of 15 parts of sulphate of iron, and 9 of sal ammo- 

 niac, in 250 parts of boiling water, and in this the zinc ar- 



Z 



