[ 39 ] 
neral, which might appear like, or be miftaken for, 
tin. I thought it very neceflary to remove all doubts, 
by making proper experiments to try if it was tin, 
before I prefumed to communicate it to this learned 
body j it being fo extraordinary a difcovery. The 
experiments I made, and which, I hope, will prove 
fatisfadtory, to convince every one that it is really 
tin, are as follow, 
1. It is perfectly dudtile and malleable} and, bent 
between the teeth, gives the fame crackling noife as 
tin always does. 
2 . In an open fire it melts eafily, calcines on the 
furface, and fmokes fomewhat } forced in a ftronger 
fire, with borax, it detonates with fmall phofphorefcent 
iparks, which is a property of pure tin. 
3- E is only corroded to a white calx in fpirit of 
nitre, and oil of tartar per deliquium being added to 
the folution, not any thing was precipitated. 
It is, therefore, pure Tin. 
I am, with great refpedt and obedience. 
Gentlemen, 
Your ever devoted, 
and moft obliged humble fervant, 
Fe t b ’/o? ' °* Emanuel Mendes da Cofta. 
VIII. A 
