[ 668 *] 
does tin ; but a large one does not near fo much, 
diminifh its malleability. A leafy or fibrous texture, 
a purplifh colour or difpofition to acquire this colour 
in the air, are peculiar to the mixtures with lead. 
Article 3. 
Platina with Silver. 
1. Equal parts of platina and of pure lilver re- 
vived from lima cornea , covered with borax, and 
urged with a ftrong fire in a blafl furnace, melted 
perfectly together, and without lofs, but did not run 
freely along the mould. The ingot was hard to the 
file, and broke from a rude blow ; though by gentle 
ftrokes it bore to be confiderably flattened. Inter- 
nally it appeared of a much duller and darker colour 
than filver, and of a coarfer texture. 
2. One part of platina and two of filver, covered 
with nitre and common fait, did not flow thin till 
the fire was raifed to a very flrong white heat. The 
compound proved lefs brittle than the foregoing, 
and not fo hard to the file : The texture was com- 
pofed of final ler grains, and the colour whiter. 
3. One part of platina and three of filver flill re- 
quired a very firong fire for their perfect fufion : The ■ 
metal was hard and brittle, though lefs fo than the 
preceding: When well and repeatedly nealed, it 
bore to be hammered, or flattened betwixt Heel roll- 
ers, into thin plates. 
4. One part of platina and Jeven of filver melted 
together with eafe. This compound hammered to- 
lerably well, proved much harder than filver, and 
not fo white, or of fo fine a grain. 
' y. Thcfe 
7 
