l6 MINERALOGICAL 
heat, according to Fahrenheit, is as 
580 : 100. It gives 34 parts of tin in 
100; when roafted it gives fome fign 
V - * 
of arfenic j the yellow colour changes 
to a reddifh ; and when thus changed, a 
fmall part is attractable by the magnet. 
I received this mineral from Mingums 
near Saint Columb, and from Saint Denis 
in Cornwall. I call it radiated yellow 
tin ore.” 
This defcription of Mr. Brunnich is 
juft, except with relpeCt to the fpecific 
gravity of the ore, and the quantity of 
tin contained in it. The firft is, accord¬ 
ing to my hydroftatical experiments with 
pure pieces, as 645 : 100; and the a flay 
gives, by a proper management, 634. 
parts of tin in 100. Mr. Brunnich men¬ 
tions this wood-tin alfo in his Minera¬ 
logy among the tin-ores: but the radiated 
tin-ore of Wallerius, from Siberia, quoted 
by Mr. Brunnich, is, according to Mr. 
Rome de 1’Ifle, not tin-ore, but wol¬ 
fram. 
In 
