306 EARTHS PROPER. 



atomic weight of alumina will be derived from 

 that mean. 



1. Nepheline gives the atomic weight 2*3126 



2. Karpholite .... 2-3013 



3. Harmotome .... 2-2985 



4. Meionite . . . . 2-3168 



5. Scapolite .... 2-0580 



6. Scolezite .... 2-2831 



7. Bucholzite .... 2-252? 



8. Leucite 2-2464 



9. Thomsonite .... 2-2395 

 10. Natrolite 2-1 754 



i 11. Felspar .... 2-2183 



12. Albite , . 2.2020 



12)26-9046 

 Atomic weight of alumina . 2-24205 



The reader will observe that the greatest 

 atomic weight of alumina is deduced from meion- 

 ite, and amounts to 2-3168, which is very far 

 short of 3'375, the atomic weight pitched upon 

 by Mr. Phillips. The least weight is 2-0580, 

 which is derived from scapolite. 



Upon the whole, the atomic weight of alu- 

 mina derived from the constitution of these min- 

 erals, though it would be hazardous to consider 

 it as quite exact, cannot be very far from the 

 truth ; and it differs from 2-25 by a very small 

 2. From fraction. 



II. .The aluminous salt most easily obtained 



