176 



Miscellanies. 



protoxide of iron, mixed with silicates of potash, lime and alumina, 

 in which the silica contains twice as much oxygen as the bases — • 

 0.75 chromate of oxide of iron mixed with oxide of tin. These 

 proportions are subject to some variations in different portions of the 

 stone. J 00 parts of the meteoric iron, contain 



Iron, 93.816 



21. Carrara marble. (O. P. H.) — It appears by the recently pub- 

 lished account of this marble, by Professor Hoffman, "that this pure 

 saccharine hmestone, in which no trace of organic matter has been 

 discovered, although in its cavities are occasionally found crystals of 

 quartz, is only transformed oolite.''^ A very wide expanse of ser- 



