124 



HYDROSTATICS. 



Oriental topaz, - 



sapphire, 



Emerald of Peru, 

 Beryl, - 

 Spinel ruby, 

 Corundum, 

 Schorl, - 

 Diamond, 

 Rock-Crystal, 

 Agate, - 

 Onyx, - 

 Mica 



Common slate, - 

 Calcareous spar, 

 Alabaster, 

 White marble, 

 Limestones, from 



to 



Chalk, - 



Brick, - 



Lithomarge, 



Heavy spar 



Fluor-spar, 



Mountain-cork, 



Pumice-stone, 



Green glass, 



English crown-glass, 



White flint-glass, English, 



Ditto, for achromatic uses, 



White glass, French, 



Augite, 



Basalt of the Giant's causeway, 



Dry ivory, 



Sulphur, 



Phosphorus, 



Ebony, 



4.010 

 3.994 

 3.775 

 3.549 

 3.760 

 3.7IO 

 3.363 

 3.521 

 2.650 

 2.590 

 2.376 

 2.792 

 2.672 

 2.715 

 2.730 

 2.716 

 1.386 

 2.390 

 2.225 

 2.000 

 2.500 

 4.474 

 3.180 

 9.993 

 0.914 

 2.620 

 2.520 

 3.290 

 3.437 

 2.892 

 2.332 

 2.846 

 1.825 

 1.990 

 1.714 

 1.117 



