t 59° 3 
lities, that may render it of fingular Ufe and Import- 
ance to Mankind. 
Specimens of Platina prefented to the Royal Society. 
N p . i. Platina , in Dud, or minute Maffes, mixed 
with black Sand, and other Impurities, as brought 
from the Spamjio Weji Indies. 
2. Native \ Platina , fepaiated from the above mcn- 
tion’d Impurities. 
3. Platina that has been fufed. 
4. Another Piece of Platina , that was Part of the 
Pummel of a Sword. 
III. 
To the Royal Society. 
Gentlemen , London, Dec. 15, 175a. 
I BEG Leave to fubjoin a few Lines to my learned 
and ingenious Friend Dr. Brownrigg’ s Paper con- 
cerning the Platina di Pinto , or what is likewife 
call’d in America Juan Blanco. This Subfiance is 
mention’d in no Author I have met with, except 
by our worthy Brother Don Antonio d'Ulloa, who, in 
theHiflory of his Voyage to South America, Vol. II. 
Book 6. Chap. 10. which I have here extradited, and 
tranflated from the Spanijh, when giving an Account 
of the Gold and Silver Mines in the Province of 
Quito, and of the varions Methods of feparating 
thefe Metals from other Subfiances, with which they 
arc combin’d, fays, that, “ in the Territory of 
“ Choco .... there are Gold Mines, in which that 
“ Metal 
