M. TECHNOLOGY. 495 



M. TECHNOLOGY. 



SILVERED STEEL CUTLERY. 



According to the London Mechanics^ Ma(/azine,Mv.Ne\\, 

 of London, has devised a process for so thoroughly uniting 

 silver with cutlery as to produce an article of great practical 

 value. It has long been the custom to electroplate silver on 

 steel ; but whenever the external coating is ground off* the 

 steel is exposed, and thereby rendered liable to rust. In the 

 present instance the knives are finished in the finest style, 

 and chemically cleaned by a special process. They are then 

 treated with perfectly pure silver, and the two are pressed 

 together by processes which are not made known by the in- 

 ventor. It is asserted that the silver is driven into the pores 

 of the steel, and that heat and moisture have no perceptible 

 effect on the metals. The result is a knife that will not rust, 

 is not stained by acids, and only requires washing after use. 

 It may be sharpened any number of times, with the result of 

 always showing a silver surface. 3 A, March 9, 1871, 21V. 



musiiet's special steel. 



" Special steel" is the name of an article manufactured by 

 Mushet with particular reference to the working of cast steel, 

 and for other purposes where the hardness of the material 

 manipulated rapidly blunts the tools. This steel does not 

 require hardening, but acquires the necessary hardness by 

 gentle hammering. It is manufactured by the Titanic Steel 

 and Iron Company, at Coleford, in Gloucestershire, England. 

 14 C, CCIIL, iv., 322. 



SILVERING OF GLASS PLATES AND GLOBES. 



According to Krippendorf, the silvering of glass plates may 

 be readily accomplished by the use of the following; 1. Sodio- 

 potassic tartrate; 2. A two per cent, solution of this salt; 3. 

 Caustic ammonia; 4. Solution of silver nitrate, 1:8 (old silver 

 bath will serve). From these the silvering and reducing liq- 

 uids are prepared. 



The reducing liquid is prepared by taking 900 cubic centim- 

 eters of distilled water, and 90 cubic centimeters of the so- 



