P. Eskola — Silicates of Strontium and Barium. 345 



Bao 



Fig. 6. 





- 



- i 



\ 





1 



1 1 1 



i ■ i i 



- 





- 





\ 

 \ 











- 



1700 





- 











*5 









- 





- 





3 I 



0~ 



-c 















cs 





c 













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a 

 in 









- 



1600 



: 



O 



VT) ' 



6 



6 j 



ia / 



i 









_ 





. 



CQ 



CQ 









Crista b a lite 



_ 





_ 



OJ 









•a / 



and liquid 



- 



















■a \ 



3 / 

















or / 











T3 







3 \ 

 O" 1 



■a / 







1500 





10 



^ 





c 



■a 



g MiXC 







_ 





rystals of r 









- 





In 



o 





05 



6 



*3 



,£26a0-3SiO 2 -BaO55iO 5 / 

 °-< and liquid / 





- 







o 



ra 





CO 













~ 



rt3 



CD 













" 













CQ 



■a 



c 



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<x 







Tri dymite 













o 

 in 





^o 





and liquid 





1400 







o 

 in 



6 



CD 





6 



CQ 

 OS 





o ._ 



<n. »* 



— o 



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t \l 









1 



















S>o" 



Bao-2s;o 2 and 



1 iqui d 



- 









CM 





re 





sS 







- 



iwn 







1 





in 

 6 

 re 



CD 





— 6 

 co 



OS 



1 



BaO-5 



i i 



0^ and ~tridym'\te 



i i i 



- 



2BaO-5iO« Ba05iO s 2Ba035i(fc Ba0-25i0 2 



510, 



Fig. 6. — Temperature-concentration diagram of the binary system 

 BaO-SiO,. 



and only 0.03 mm thick. The terminal angles were 

 approximately 100° and the lateral angles 130°. The 

 crystals are orthorhombic, the negative acute bisectrix 

 being parallel to the elongation, and the plane of the optic 

 axes parallel to the platy development, which is a good 

 cleavage. 2V a = 70° approximately y = 1.613 ; a = 1.595. 



