schaller: composition of nephelite 



111 



one by Foote and Bradley and the second one by Morozewicz 

 (No. V — reference given in paper of Foote and Bradley). These 

 have been chosen as they are among the best analyses and show 

 a minimum amount of other bases such as CaO, Fe 2 3 , etc. 



The nephelite analyzed by Foote and Bradley consists, as cal- 

 culated from their ratios, of the following compounds in the pro- 

 portions indicated. 



Composition of nephelite (Foote and Bradley) 



60 parts or 19.0 per cent of KAlSi0 4 

 245 parts or 70.4 per cent of NaAlSi0 4 

 21 parts or 10.6 per cent of XaA]Si 3 8 . 



The comparison of the analysis with the figures calculated from 

 the above composition is very close, as is shown below. 



Comparison of Analysis with Calculated Values 



Analyses No. V of Morozewicz yields the following composition: 



Composition of nephelite (No. V Morozewicz) 



62 parts or 19.7 per cent of KAlSi0 4 

 259 parts or 74.7 per cent of NaAlSiO-4 

 11 parts or 5.6 per cent of NaAlSisOs. 



As in the other case, the comparison of the analysis with the 

 values calculated from the above composition, shows a very close 

 agreement. 



