7nade with a View to its Irnprovi.me7it . 33 



effected with tlie same facility as could have been doiie with steel 

 and iron. On being forged, the surface polished, and the steel 

 slightly acted on by an acid, a very novel and beautiful surface 

 appeared, the steel and platinum forming dark and white clouds : 

 if this can be effected with very fine wires, a damasked surface 

 will be obtained, of exquisite beauty. This experiment, made 

 to ascertain the welding property of platinum, is only named 

 here in consequence of observing that some of the largest of the 

 steel clouds had much the appearance of being alloyed with a 

 portion of the platinum. A more correct survey of the surface, 

 by a high magnifying power, went far to confirm 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, whieh 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. 



Ninety 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. 



Ten of platinum to SO of steel formed an excellent alloy. This 

 was ground and very highly polished to be tried as a mirror 3 a 

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



The propoitions 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 possible alloy of these metals; 1-5 per cent, will probably 

 be very nearly right. At the time of combining 10 of platinum 

 with SO steel^ with a view to a mirror, the same proportions were 

 tried with nickel and steel ; this too had the damask, and con- 

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

 difference betWL-en these two alloys, as to susceptibility for oxy- 

 gen. 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 circumstances. 

 This is given as an instance, showing that nickel with steel is 

 much more subject to oxidation than when combined 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 rho- 

 dium, but also for a liberal .supj)lv of the metal, as well as much 

 Vol. 50. No. 267. July 1^20. ' E valuable 



