208 Messrs. Stodart and Faraday on [March, 



exhibited a crystalline appearance ; the crystals, being elongated 

 by forging, and the surface again polished, gave, by dilute acid, 

 a very beautiful damask. Again, 1600 grains of steel with 48 

 of pure chrome were fused : this gave a button considerably 

 harder than the former. This too was as malleable as pure iron, 

 and also gave a very fine damask. Here a phenomenon rather 

 curious was observed : the damask was removed by polishing, 

 and restored by heat without the use of any acid. The damasked 

 surface, now coloured by oxidation, had a very novel appearance : 

 the beauty was heightened by heating the metal in a way to 

 exhibit all the colours caused by oxidation, from pale- straw to 

 blue, or from about 430° to 600° of Fahr. The blade of a sabre, 

 or some such instrument, made from this alloy, and treated in 

 this way, would assuredly be beautiful, whatever its other pro- 

 perties might be ; for of the value of the chrome alloy for edge 

 tools we are not prepared to speak, not having made trial of its 

 cutting powers. The sabre blade, thus coloured, would amount 

 to a proof of its being well tempered ; the blue back would indi- 

 cate the temper of a watch spring; while the straw colour 

 towards the edge would announce the requisite degree of hard- 

 ness. It is confessed, that the operation of tempering any 

 blade of considerable length in this way, would be attended with 

 some difficulty. 



In the account now given of the different alloys, only one 

 triple compound is noticed ; namely, steel, iridium, and osmium ; 

 but this part of the subject certainly merits further investiga- 

 tion, offering a wide and interesting field of research. Some 

 attempts to form other combinations of this description proved 

 encouraging, but we were prevented, at the time, by various 

 other avocations, from bestowing on them that attention and 

 labour they seemed so well to deserve.* 



It is a curious fact, that when pure iron is substituted for 

 steel, the alloys so formed are much less subject to oxidation. 

 Three per cent, of iridium and osmium fused with some pure 

 iron, gave a button, which, when forged and polished, was 

 exposed, with many other pieces of iron, steel, and alloys, to a 

 moist atmosphere : it was the last of all showing any rust. The 

 colour of this compound was distinctly blue ; it had the property 

 of becoming harder when heated to redness and quenched in a 

 cold fluid. On observing this steel-like character, we suspected 

 the presence of carbon ; none, however, was found, although 

 carefully looked for. It is not improbable that there may be 

 other bodies, besides charcoal, capable of giving to iron the 

 properties of steel ; and though we cannot agree with M. Bous- 

 singault,f when he would replace carbon in steel by silica or its 



• It is our intention to continue these experiments at every opportunity, but they are 

 laborious, and require much time and patience, 

 t Annales de Chimie, xvi. 1. 



