P. Eskola — Silicates of Strontium and Barium. 355 



The same is expressed in the diagrams (fig. 11) in 

 which is also shown the variation in the index of refrac- 

 tion in the strontium and calcium metasilicate glass. 



(.660 

 1.655 

 1.650 



1.645 

 1.640 



1.635 

 1.630 

 1.625 

 1.620 

 1.6*5 

 1.610 

 1.605 

 (.600 



Fig. 11. — Variation of the indices of refraction in the mix crystal series 

 CaO.Si0 2 -SrO.Si0 2 . 



The System CaO.Si0 2 -BaO.Si0 2 . 



While strontium and calcium metasilicates give • a 

 complete series of solid solutions and apparently are 

 perfectly isomorphous, barium metasilicate does not mix 

 at all with calcium metasilicate. Instead of this there 

 occurs a double compound, 2CaO.Ba0.3Si0 2 , which, how- 

 ever, has no true melting point, but breaks np into a-CaO. 

 Si0 2 and liquid. Those quenches which yielded impor- 

 tant results are quoted below in table VI. 











Fig. 11. 













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