[ 45 ° 1 
It may be obfcrved, that it appears by this table, 
that the fpecific gravities of ores, including the me- 
tallic ftones, are ufualiy found to lie between 7 and 
3 times the weight of water* Lead and Silver ores 
are the heavieft, thofe of Copper, Tin and Iron be- 
ing confiderably lighter. The Gold Ore we have 
an account of mud be fo poor as hardly to be worth 
taking any notice of: but we have in general too 
few of thefe experiments, to draw any certain con- 
clufions from them. 
TABLE III. 
Of GemSy Chryftals , Glafs> and tranfparent 
Stones . 
GRANATE, Bohemian. Boyle . 
Granate. J. C, . . . 
Granati minera. Boyle . 
A Pfeudo-Topazius, being a natural pellucid, 
brittle, hairy (tone, of a yellow colour. 
Newton . C. 
Sapphires. ‘Davies. . . . 
A Sapphire very perfeft, but rather pale. 
Hauksbee. . . 
Glafs, blue in flicks from Mr. Seale. 
Hauksbee. . .. 
D°. whiteft, from Mr. Seale. Hauksbee . 
D Q . clear chryftal. Cotes. . 
D°. blue plate, old. Hauksbee. 
Do. plate. L, 
4.360 
3.978 
3.100 
4 270 
4.090 
4.068- 
3 885- 
3.380 
3 - J f° 
3-102 
2.942 
D°. 
