of the double refraction in strained glass. 



61 



Table II. 

 July 9— 11th. a: = 40. 



Table III. 

 July 11th. x = 45. 



where in the above G is expressed in 10~ 8 sq. cms. per kilo- 

 gramme weight. 



6. The above results have been plotted together in Fig. 3, 

 the points belonging to the three different sets of observations 



