362 Mr Stodiirt and Mr Faraday 
loy for edge tools we are not prepared to speak, not having 
made trial of its cutting powers. The sabre blade thus colour- 
ed^ would amount to a proof of its being well tempered ; the 
blue black 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 operation of tem- 
pering 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 farther investigation, 
offering a wide and interesting field of research. Some attempts 
to form other combinations of this description proved encour- 
aging ; but we were prevented, at the time, by various other avo- 
cations, 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. 
^ per cent, of iridium and osmium fused with some pure iron, 
gave a button, which, when forged and polished, was exposed, 
with many otlier pieces of iron, steel, and alloys, to a moist at- 
mosphere : it was the last of all showing any rust. The colour 
of this compound was distinctly blue ; it had the property of be- 
coming 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 care- 
fully 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, Boussingault 
when he would replace carbon in steel by silica or its base, we 
think his experiments very interesting on this point, which is 
worthy of farther examination. 
We arc not informed as to wh.at extent these alloys, or any 
c'f them, have been made at home, or to what uses they have 
been applied : their more general introduction in manufacture 
** It is our intention to continue these experiments at every opportunity; but 
they are laborious, and require much time and patience. 
'j- Annalcs do Chimie, xvi. 1. 
