418 



Dr. L. Vegard on 



calculations I should give the following intervals for their 

 values : 



33 < <£ < 37, 

 fO-45 < f < 0-75*. 



In Table V. are given the amplitudes calculated from (186) 

 by putting 



<P = 35° and /== 0*5; 



and, for the sake of comparison, are given the amplitudes 

 calculated directly from the observed intensities by means 

 of the relation 



where we have put 



h x = 1, i 8 = 1/3, h - 1/7, h = 1/12. 



Table Y. 



Face. 



Oalcu 



lated from the lattice. 



Calculated from observations. 





















Ax- 



A, 



A,. 



A 4 . 



A r 



A 2 . 



A, 



A 4 - 



(100) 



100 



90 



85 



73 



100 



85 



98 



73 



(110) 



46 



86 



100 



54 



36 



75 



100 



63 



(001) 



18 



36 



3 



100 



21 



30 



0(?) 



100 



(101) 



51 



33 



100 



68 



52 



44 



100 



72 



(111) 



100 



42 



13 



58 



100 



48 



(weak) 



72 



When we take into account the difficulty in obtaining 

 accurate intensity values and the uncertainty with regard 

 to k n , the agreement between the values given by the 

 lattice and those obtained from observation is very good. 

 Although small differences may exist, the amplitudes 

 calculated from the lattice will give just the typical dis- 

 tribution of intensities observed. 



* It is to be remembered that we might also give f negative values, 

 which would mean that the hydrogen atoms were placed on the lines 

 between the C atoms of a group. But a negative value is unable to 

 explain the intensity distribution. 



