[ 669 ] 
5- Thefe com portions, weighed hydroftatically, 
turned out like the others, a little lighter than by cal- 
culation : But the difference, which before feemed 
to increafe with the platina, was here greateft when 
the platina was in lead: proportion. 
-■ . 
Specific Gravily. 
By Experiment. 
By Calculation. 
Difference. 
Platina * 
OOO 
Platina 1, 
Silver 1 
I 3 * 
535 
13- 
990 
O. 
455 
Platina 1, 
Silver 2 
12. 
45 2 
12. 
987 
O. 
535 
Platina 1, 
Silver 3 
11. 
790 
12. 
485 
O. 
695 
Platina 1, 
Silver 7 
TO. 
867 
11. 
73 2 
O. 
865 
Silver 
IO. 
980 
Remark . Platina appears to unite more difficultly 
with ftlver than with either of the foregoing metals. 
Even when the proportion of the platina is fmall, the 
greateft part of it fubftdes upon an abatement of the 
heat, by which the union had been effected. This 
was prevented by pouring out the metal, when per- 
fectly fluid, at one jet, into a broad mould > in which 
the compound begun to congeal before the platina 
could feparate. 
Platina diminifhes the malleability of filver far lefs 
than that of tin or lead ; and does not, in whatever 
proportion employed, fo much debafe its colour, or 
difpofe it to tarnilh in the air. 
Article 4. 
Platina with Gold. 
1. Equal parts of platina and gold, expofed to 
an .intenfe fire, melted perfectly together, and ran 
