268 
Mr. Stodart and Mr. Faraday 
of a sabre, or some such instrument, made from this alloy, and 
treated in this way, would assuredly be beautiful, whatever its 
other properties 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 co- 
loured, would amount to a proof of its being well tempered ; 
the blue back would indicate the temper of a watch spring, 
while the straw colour towards the edge would announce the 
requisite degree of hardness. It is confessed, that the opera- 
tion 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 os- 
mium ; but this part of the subject certainly merits farther 
investigation, 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 atten- 
tion 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. 
3 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 co- 
lour 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 sus- 
* It is our intention to continue these experiments at every opportunity, but 
they are laborious, and require much time and patience. 
