228 



F. E. Wright — Schistosity by Crystallization. 



second normal to the side planes (010), while the front and 

 back planes (100) remain free in every experiment. 



Jn view of the fact that more extended experimental work 

 on the influence of stress on crystallization under bettered con- 

 ditions is soon to be carried out in this laboratory, three photo- 

 micrographs of simple cases only are reproduced below. The 

 results, here presented, are strictly qualitative and preliminary 

 in character. 



Figure 1 shows a plate through the central part of a large 

 cube of wollastonite crystallized from its glass under stress 



Magnification 25 x . Nicols crossed. 

 Yig. 2. — Section parallel to 010 of a cube of anorthite crystallized from 

 its glass under stresses in the direction marked by the arrows. 



normal to 001. The section was cut parallel to 100 and in it 

 the wollastonite fibers are oriented approximately perpendicu- 

 lar to the line of stress. Local variations occur and an indi- 

 vidual fiber may occasionally be inclined at an angle of many 

 degrees to the normal plane. Nevertheless, the general effect 



