[ 5 « 9 .] 
my Opinion, evident Marks of having been fufed and 
caff They very much refemble, as you will fee by 
comparing them, the Platina before ment on’d : 
And though they are call’d (Pddras) Stones by 
Don Antonio d’Ulloa , he likewife gives the fame 
Appellation to the Platina. I cannot therefore 
help recommending to fome curious Metallurgift of 
the Society to make the Experiment, whether or 
no, when the Piedras de Inga are, by a proper 
Procefs, divefted of their Bony and other heteroge- 
neous Parts, the metalline Rejiduum will not refera- 
ble, as well in fpecilic Gravity (tor which it is fo 
remarkable) as in other Properties, the purified Wz- 
tina now before us ? 
Wm. Watfon. 
IV. 
I i 
N y unitary 1742-3. there were brought 
from Jamaica , in a Man of War, feve- 
ral Bars (as thought) of Gold, conltgned from different 
Merchants of that Bland, to their different Correfpon- 
dents here, as Bars of Gold. Thefe Bars had the fame 
fpecific Gravity, or rather more than Gold, and were 
exadly like that Metal in Colour, Grain, &c. A 
Piece of one of thefe counterfeit Bars was fent to the 
Mint to be tefted, and it was found to be twenty one 
Carats three Grains worfe than Standard. 
Emanuel Mendez da Cofta, 
V. 
