362 P. Eskola — Silicates of Strontium and Barium. 



very exactly, while those of the acid end should be fairly 

 accurate, and the data given here may be, in the case of 

 the barium silicate, of some practical interest to the 

 manufacturer of optical glasses. 



In tables IX and X are given the determinations of 

 refractive indices of glasses in the systems CaO.Si0 2 - 



SrO.Si0 2 and CaO.SiO,-BaO.SiO ? 

 expressed in fig. 16. 



The 



same is 



Fig. 16. 



100 wt % 80 

 Ca0-5i0$> 



Fig. 16. — Variation of the' indices of refraction in glasses of CaO.Si0 2 . 

 SrO.Si0 2 and CaO.Si0 2 -BaO.Si0 2 . 



