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PHILADELPHIA, June 16, 1815, 
iSear sir, 
I have to express to you my thanks for the honourable mention 
you have made of my late exertions in the first number of your 
Emporium, Perhaps I could have wished, if you will excuse the^ 
observation, that the article had been a little more accurate. I 
have rendered platina malleable, which is a chemical process, but 
to work it up afterwards into spoons, See. Sec. is the business of art- 
ists, and mechanics. Our wags will say, u so the Dr. has turned 
Spoon-maker at last,” and they will have your word for it. 
You also mention as a general, and apparently steady thing, that 
the specific gravity of my platina is 19.7 — which happened to be 
the specific gravity of the ill hammered specimen you took with 
you. It generally weighs 21.5, and I have had several pieces of 
a specific gravity of 22.5. I must repeat on this occasion, that 
great specific gravity is not absolutely a proof of purity. A piece 
of pure platina of 19.5 may be hammered into a specific gravity 
of 23. and a less pure, but better hammered, that is compacter 
piece, may exceed in specific gravity a piece more pure. — We even 
know that the specific gravity of brass is greater than that of pure 
copper, though the specific gravity of zinc is inferior to that of 
copper ; which proves that greatest density, and compactness of 
a substance — on which its specific gravity depends, does not neces- 
sarily imply its greatest purity. 
As the article stands it gives the impression, that I only do what 
Mr. Cloud did before, but better. The fact however is, that Mr. 
Cloud, w T hose merits I well know and fully acknowledge — does 
not seem to have intended more than to produce a cabinet piece of 
the greatest possible purity and specific gravity, and he has done 
so: but I have first rendered platina malleable in this country, by 
means of a process, which admits being executed on a large scale, 
and which, I hope, will become beneficial to the arts, and to soci- 
ety.— Pieces have been made of the weight of two pounds, and up j 
wards. Sheets have been rolled of thirteen inches square, and 
vessels of platina are now making, and in preparation, which will 
hold from twenty to thirty gallons. 
The method I use is not the one you describe, and which could 
not be executed in the large way with safety, accuracy and dispatch. 
I have found hints of it in European publications, but I believe I. 
