[ 6 S t ] 
fal ammoniac, feparately, in four times their weight 
of aqua fortis ; and by abftradting t he nitrous fpiri 
from the fame proportion of each of the falts 
With all thefe menftrua the folution feem'd to fuc- 
ceed equally. 
3. In order to determine the quantity of men- 
ftruum neceftary for the folution ; three ounces of an 
extremely ftrong aqua regia, diluted with water, were 
pour’d upon one ounce of platina, in a retort, to 
which was adapted a recipient. A gentle heat being 
applied, the menftruum adted violently, and red 
fumes arofe in abundance. When about two-thirds 
of the liquor had come over, the adtion w^as fcarce, 
if at all, fenfible, though the fire was confiderably 
rais’d. The diftill’d liquor, which appear’d of a 
light redifh colour, being pour’d back again into the 
retort, the folution began afrefh ; the vapour, which 
now came over, appear’d pale, compar’d with the 
firft. The cohobation was repeated four times, the 
diftill’d liquor proving paler and paler every time : 
At length, both the fumes and adtion ceas’d, though 
the fire was rais’d, and a confiderable part of the 
platina remain’d undiftolv’d. The folution was there- 
fore pour’d off, fome more of the menftruum added, 
the diftillation and cohobation renew’d, and this oc- 
cafionally repeated, till the whole w r as taken up, ex- 
cepting a little blackifti matter, of which hereafter. 
The quantity of ftrong aqua regia, employ’d for dif- 
folving the ounce of platina, was five ounces ; but 
the lafi: parcels appear’d from their yellow colour not 
to be fully faturated, and, upon trial, were found to 
take up near fifty grains of frefh platina. 
4N2 
Remark . 
