Buddington — Natural and Synthetic Melilites. 77 



Table XXIV. 



Comparison of Humooldtilite analyses with calculated composition of isomor- 



plious mixtures. 



Original 

 analysis 



SiO, 39.86 



ALA 11-37 



Fe,0 3 50 



Feb 1.78 



MgO 7.63 



CaO 35.58 



Na,0 2.13 



LLO 82 



Humooldtilite A. 



Analysis Calculated Differ- 



redueed. Mol. molecules ence 



39.98 



11.41 



.50 



1.79 



7.65 



35.69 



2.15 



.83 



6630 



1116 



31 



249 

 1898 

 6362 



347 



6634 



1041 



39 



230 

 1831 

 6563 



347 



+ 



4 



75 



— 19 



— 67 



+201 



50 



24 

 10 



Mixture 

 weight percent. 

 2CaO.MgO.2SiO., 

 3CaO.Al,O v 3SiO", 

 2CaO.AlA.SiO, 

 2CaO.FeO.2SiO", 

 3(Na,K),0.AlA- 



3Si0 2 

 3CaO.FeA.3SiO, 



Original 

 analysis 



SiO, 41.69 



ALA 9.59 



FeA 76 



Feb 3.75 



MgO 5.32 



CaO 32.82 



Na,0 4.76 



K,6 68 



Humooldtilite B. 



Analysis Calculated Differ - 



reduced. Mol. molecules ence 



41.94 



9.65 



.77 



3.78 



5.36 



33.02 



4.79 



.69 



6958 



944 



48 



527 



1330 



5886 



773 



73 



6844 



969 



59 



525 



1355 



5998 



773 



73 



—114 



+ 25 



+ 11 



— 2 



+ 25 

 +112 



Mixture 

 weight percent. 

 37 2CaO.MgO.2SiO, 

 31 3CaO.ALA.3SiO, 

 16 2CaO.FeO.2SiO, 

 13 3(Na,K),0.ALA 



3SiO, 

 3 3CaO.Fe 2 3 .3SiO, 



Original 

 analysis 



SiO, 40.36 



ALA 12.04 



Fe 2 3 75 



FeO 1.53 



MgO 6.56 



CaO 34.71 



Na,0 3.34 



K,0 30 



Analysis 



reduced. 



40.52 



12.09 



.75 



1.54 



6.60 



34.85 



3.35 



.30 



Humooldtilite C. 



Calculated Differ- 

 Mol. molecules ence 



• 66 

 6 



■ 7 



• 17 

 63 



6719 



1185 



47 



214 



1638 



6223 



540 



32 



6653 



1191 



40 



197 



1575 



6373 



540 



32 



+150 



Mixture 



weight percent. 



2CaO.MgO.2SiO, 



3CaO.Al,0,.3Si0 2 



3(Na,K),.ALA. 



3 SiO, 

 2CaO.FeO.2SiO, 

 3CaO.FeA 3 .3Si0 2 



In Table XXIV are given the original chemical 

 analyses of the humboldtilites, the analyses rednced to 

 ,100 per cent, the constituent molecules, and for com- 

 parison the calculated molecules of the mixture of 

 assumed components most closely approximating the 

 natural mineral in composition. 



In Table XXV are given the results of recalculating the 

 first three analyses of Table XXIII in terms of their 

 assumed components, together with the optical characters 

 of the minerals analyzed. 



