C 449 ] 
Antimony may in like manner be confidercd as 
a compofition of its Regains and Sulphur. 
The black fand ufed on writing is faid by Mr. 
Boyle to be a rich Iron Ore : healfo fays thatEmeri, 
Loadftone, and all fuch ponderous ftones, contain 
lome kind of metal, which he had himfelf feparated 
' from them. IV. 120. a. 
The great variety of Ores of all kinds well de- 
ferve to be accurately examined, for the fake of the 
many conclufions that may be drawn from thence, 
concerning the natures of concrete bodies, and for 
many other purpofes in Metallurgy. But I have as 
yet met with a very fmall number of experiments 
upon thefe fubftances. Dr. IVoodward has indeed 
mentioned a great many obfervations of this fort 
which he had made, and kept exad regifters of : 
but as they were probably among thofe papers which 
he order’d to be deftroy’d at his death, we mud 
look upon them as now loft to the world. 
The Marcafites and Pyrites are very uncertain and 
ftrange kinds of bodies, their gravities are often 
very great : a Marcafite here taken from Fahrenheit 
was found nearly to equal the heavieft mineral Bif- 
muth itfelf j and yet it is very fpldom that any Me- 
tal or femimetal can be obtained in any quantity 
from thefe fubftances, all that is in them being 
ufually deftroyed, and carried away by their fulphur. 
Black Lead is alfo a very odd kind of Mineral, 
having all the appearance of a $eminjetal, and yet 
falling fhort even of the weight of common earth. 
The Semimetals generally exceed in their fpecific 
gravity even the bafer Metajs themfelyes. 
N n n z 
It 
