[ 6 73 ] 
in its perfed malleable (late. But as the fluxes ne- 
ceflary for rendering forged iron fufible corroded 
the crucibles before the metal flowed thin enough to 
diflolve the platina, pure call iron was fubftituted. 
1 . Cafl: iron and platina, of each three ounces, ex- 
pofed without addition to a ftrong fire, united into 
a thick fluid j which, on adding an ounce more of 
iron, flowed thin. The compound fuffered to cool 
in the crucible (which had become too foft from 
the heat to admit of its being poured out) was 
found, on breaking the veflfel, in one lump, not con- 
vex, the form, which the iron ufually aflumes, but 
of a very concave furface : The weight about one- 
fixtieth lefs than that of the metals employed. It 
proved exceflively hard, fo as not to be touched by 
the file ; and fo tough, as not to be broke by repeat- 
ed blows of a fledge-hammer, from which it received 
fome imprefiion. Heated red, it broke eafily, and 
looked internally of an uniform texture, compofed 
not of bright plates like the iron at firft, but of 
very dark-coloured grains. 
2. One ounce of platina being injected upon four 
of cafl; iron beginning to melt, and the fire kept up 
ftrong, the whole came quickly into fufion, and on 
cooling, formed an equable compound, which like 
the former proved extremely hard, and feemed to 
ftretch a little under the great hammer without 
breaking. The colour was ftill very dark, though lefs 
fo than when the platina was in larger proportion. 
3. One part of platina and twelve of iron melted 
without difficulty, and with little or no lofs. This 
compound was ftill much harder than the iron at 
firfl, and had a very confiderable degree of tough- 
4 nefs. 
