[ 6 S7 ] 
A few drops of a folution of platina were there- 
fore mixed with above an hundred times the quan- 
tity of a folution of gold ; the whole diluted with 
water ; and a pure alcaline fait gradually added, as 
long as it occaiioned any eftervefcence or precipita- 
tion. The remaining liquor was of fo deep a yellow 
colour, that it was judged the platina would have 
difcovered itfelf, though its proportion had been lefs 
than one thoufandth part of that of the gold. 
< 
Experiment 8. 
1. Zinc, which totally precipitates all the other 
known metallic bodies, put into a diluted folution of 
platina, was very quickly adled on, and threw down 
a blackilh calx. The liquor in good meafure pre- 
ferved its yellow colour ; a mark, that part of the 
platina remained fufpended. 
2. Iron, which precipitates all the metals from 
their folutions, except zinc, threw down a fimilar 
calx. It could not be judged by the eye, whether 
the precipitation was complete, the folutions of iron 
and platina nearly agreeing with one another in co-- 
lour. 
3. Copper, the precipitant of mercury and gold, 
readily threw down platina from its folution, in forni 
of a greyifh calx, which was found upon trial to re- 
tain a notable quantity of the copper. The liquor 
remaining after the platina had fallen was of a more 
dulky green than folutions of pure copper, probably 
from its retaining fome of the platina. 
4. Mercury, which precipitates gold alone from 
aqua regia, put into a diluted folution of platina, 
feemed in a little time to be divided, and did not 
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