CALIFORNIA ACADEMY OF SCIENCES. 15 



s : g =.(oo P:0P) = 106 D T 0" 



106 10 43 



106 10 50 



106 11 



106 11 30 



106 12 20 



106 15 50 



Mean 106° 11' 29" 



/i:j = (2Poo:OP)= 111 31' 57" 



111 32 



111 32 33 



111 35 39 

 111 36 

 111 36 



111 36 28 



111 36 40 



111 37 5 



111 37 7 



111 37 17 



111 37 30 



111 38 24 

 111 39 



Mean 111° 35' 58" 



It seemed, therefore, unnecessary to re-calculate the axial 

 elements with these mean values. It will be noticed that there 

 is a very fair agreement between the measured and calculated 

 angles, and also that the variations of the same angle in different 

 crystals take place both ways from the calculated value in the 

 greater number of instances. 



