296 EARTHS PROPER. 



5. SCAPOLITE. 



Scapoiite We have a very careful analysis of this mineral 



in a state, apparently, of great purity, by Mr. 



NordenskiolcL* He found its constituents as 

 follows : 



Silica . . 43-83 



Alumina . 35-43 



Lime . . 18-96 



Water . . 1-03 



99-25 



The only difference between the composition of 

 meionite and scapolite seems to be, that the 

 former contains only 2 integrant particles of sili- 

 cate of alumina united to 1 integrant particle of 

 silicate of lime, while the latter contains 3. 



Let us calculate the constitution of this mineral 

 on the same supposition as of meionite : 



(1.) 2-25 : 2 : : 35-43 : 31-049 = silica united to alumina. 

 (2.) 3-5:2:: 18-96 : 10-834 = silica united to lime. 



Now, 31-049 + 10-834 = 41-883, which is less 

 than the silica found in the mineral by 1-947 

 grain. Of this surplus, Jth, or 0.487 must be unit- 

 ed to the lime the remaining 1-460 grain must 

 be added to the 31-049, making 32-409. And 



Gives 32-409 : 35-43 : : 2 : 2-0580 = atomic weight of alumina. 



2 0580. 



* Bidvag till Narmare Kannedomaf Finland's Mineralier och Geogno- 

 sie, p. 63. 



