DALY. — AMPHIBOLES AND PYROXENES. 



315 



TABLE I. 



metry itself. I refer to the plane of prismatic cleavage. Table I. 

 contains the results of calculations (repeated applications of equation 2), 

 intended to find the value of 0, (6'), for amphiboles when Cis equal to half 

 the cleavage angle (taken at 62^°), 2 Fat successive values of 50°, 60°, 

 70°, 80°, and 90°, and p with all values of whole degrees from 2° to 25° 

 inclusive. Thus, if any two of the three terms 2 V, p, or 6' be known, 

 the third can be determined. The values of $' are tabulated in the col- 



