328 On the Alloi/s of Steel. 



this curious fact ; some more direct experiments are proposed 

 to be made on this apparent alloy by cementation. 



The alloys of steel with platinum, when both are in a state 

 of fusion, are very perfect, in every proportion that has been 

 tried. Equal parts by weight form a beautiful alloy, which takes 

 a fine polish, and does not tarnish ; the colour is the finest 

 imaginable for a mirror. The specific gravity of this beautiful 

 compound is 9.862. 



90 of platinum with 20 of steel, gave also a perfect alloy, 

 which has no disposition to tarnish, the specific gravity 15.88; 

 both these buttons are malleable, but have not yet been applied 

 to any specific purpose. 



10 of platinum to 80 of steel, formed an excellent alloy. This 

 was ground and very highly polished to be tried as a mirror ; 

 a fine damask, however, renders it quite unfit for that purpose. 



The proportions of platinum that appear to improve steel for 

 edge instruments, are from 1 to 3 per cent. Experience does not 

 yet enable us to state the exact proportion that forms the best pos- 

 sible alloy of these metals ; 1.5 per cent, will probably be very 

 nearly right. At the time of combining, 10 of platinum with 80 

 steel, with a view to a mirror, the same proportions were tried with 

 nickel and steel ; this too had the damask, and consequently 

 was unfit for its intention. It is curious to observe the difier- 

 ence between these two alloys, as to susceptibility for oxygen. 

 The platinum and steel, after laying many months, had not a 

 spot on its surface, while that with nickel was covered with 

 rust ; they were in every respect left under similar circum- 

 stances. This is given as an instance, shewing that nickel 

 with steel is much more subject to oxidation than when com- 

 bined with iron. 



The alloys of steel with rhodium are likely to prove highly 

 valuable. The scarcity of that metal must, however, operate 

 against its introduction to any great extent. It is to Dr. Wol- 

 laston we are indebted, not only for suggesting the trial of 

 rhodium, but also for a liberal supply of the metal, as well as 

 much valuable information relative to fuel, crucibles, S(c. ; this 

 liberality enables us to continue our experiments on this alloy; 



