Results of Crystal Analysis. 



«9 



(110) and (100) faces, the values of /3 and a 2 may be inter- 

 changed without altering the value oifi{n) ; and consequently 

 we might equally well satisfy these faces with a 2 = '60° and 

 j3 = 60°. Tlie face (101), however, does not permit such an 

 interchange, and the fact that this face gives a comparatively 

 strong second order reflexion will make the combination 

 /S = 60°, « 2 = 30° impossible. 



With our present knowledge with regard to the laws 

 governing the intensity variations we cannot claim a very 

 great accuracy for the angles a 2 and /3. In the present case 

 our experimental material is also somewhat limited — thus, if 

 accurate intensity measurements for the (101) and (100) 

 faces were available, we should probably reduce the possible 

 errors in the values of (3 and u 2 still more. 



In Table VI. are given the values of A 2 and the calculated 

 and observed intensities corresponding to /3 = 30° and a 2 = 60° 

 for the faces (111) and (101). 



Table VI. 





(Ill) 



(101) 



n. 



A 2 . 



leal. 



lobs- 



A' 2 . leal • 



lobs- 



1 



2 



3 



4 



5 



6 



2-73 

 4-0 

 96 

 60-0 

 6-3 

 4 



91 

 40 

 38 

 100 

 3 

 0-7 



80 



40 



40 



100 



5 







9-5 100 



11-4 36 



5*6 7 



100 

 56 



8 



The agreement between calculated and observed values is 

 a very good one, and in view of the fact that the intensities 

 of the other faces are also explained, we see that there can 

 be no doubt that the lattice given in Table IV. is the right 

 one, and that we have found very nearly the true values of 

 ol 2 and /3. 



The values found for these angles give the following 

 values for the two parameters of the lattice : 



«j __ 7T — /3 



5 



4z7T 4z7T 

 cc 2 1 



4tt == 12' 



" 21' 







