EARTHS PROPER. 



The silica united to the barytes being -fth of the 

 whole, fth of this excess must be referred to 

 that portion. There remains O9, which must 

 be subtracted from the 42-666 grains of silica, 

 given by theoryas united to the alumina. This 

 being subtracted, leaves 41 '766 for the silica ac- 

 tually combined with the alumina, according to 

 Klaproth's analysis. Now, 



4.1-766 : 16 : : 6 : 2-2985 = atomic weight of alumina. 

 4. MEIONITE. 



Of this mineral, which occurs most abundant- 

 ly on Monte Somma, near Naples, but which 

 has been found also in other places, and indeed 

 is probably identical with scapolite, we have se- 

 veral very careful analyses.* 



According to the experiments of Dr. L. 

 Gmelin of Tubingen, its constituents are as fol- 

 lows :t 



Silica . . . 40-8 



Alumina . . 30-6 



Lime . . . 22-1 



Soda, with some lithia 2-4 



Oxide of iron . 1-0 



Carbonic acid and loss 3-1 



100-0 



* The mineral analyzed by Arfwedson, from which Berzelius has taken 

 his notion of the coin position of nieionite, was obviously a leucite. 

 f Sch\veif?ger, XXV. 36. 



