History (^‘Chemical Discoveries. Sll 
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 men- 
tioned 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. 
3. Steel and Platmum.-^'Y\iQ 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, form an excellent alloy. This 
was ground and very highly ]}olished 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 possible alloy of these metals; 1.5 per cent will probably 
be very nearly the best. At the time of combining, 10 of plati- 
num with 80 steel, with a view to a mirror, the same propor- 
tions were tried with nickel and steel ; this too had the damask, 
and consequently was unfit for its intention. It is curious to 
observe the difference between these two alloys, as to suscepti- 
bility for oxygen. The platinum and steel, after lying 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. 
3. Steel with Rhodium.’^’Tha alloys of steel with rhodium 
are likely to prove highly valuable. The scarcity of this metal 
must, however, operate against its introduction to any great ex- 
tent. The proportions we have used are from 1 to 2 per cent. 
