121 
within the nucleus). Moreover the structure-pattern of the crystal 
is not the only factor that influences the intensities of the RÖNTGEN- 
beams reflected by the different planes, but there are more factors 
viz. the polarisation — the number of planes — the temperature- 
and the summation-factor calculated for this case by Desur and 
SCHERRER. 
I therefore thought it better to wait with my conclusion till 1 had 
finished the measurements on other elements with diamond-structure. 
As such Si, Ti and grey Sn‘) in the first place came into con- 
sideration °). By these measurements I hoped to be able to separate 
better the different influencing factors. 
As however in these Proceedings XXII p. 536 Cosrrr has 
treated the question of the binding rings, my considerations and 
calculations may be already of some interest, especially as in some 
principal points and in the conclusion they do not agree with Cosrer’s 
paper. When my measurements on this subject are finished I hope 
to come back to the question. 
§ 2. In the main DeBije and Scuerrer base their declining con- 
clusion on the fact, that the line (222) that fails on the photos, 
should be one of the most intensive according to the simplified 
model. This is directly evident from fig. 1 taking the distribution of 
the particles over the planes into consideration. Here the full lines 
indicate the relative positions of the planes (111) or (222) of the 
nuclei with the inner Bour-circles concentrated in them. The broken 
lines represent the binding rings concentrated in their centre. 
2 When however the approximation is 
used no longer, each plane a remains 
plens! DA} _unchanged, each plane b is split up into 
| «Ay 6 planes that oscillate. 
is When we want to investigate how this 
influences the structure-factor, we must 
know the simultaneous positions of the pairs of electrons of the 
different rings. 
When we wish thereby to take into consideration the symmetry 
of the point-system, where now moving elements occur, the sym- 
DIE Vee. 
metry-elements which could be called “axis of rotation’, “‘screw-axis” 
1) A. J. Bur and N. H. KorkMeEweEr. These Communications NO. 2b. These 
Proceedings 27 (1918) p. 359. 
2) Rightly CosTER remarks (These Proc. XXII p. 541) that also measurements 
on Ge would be of interest. 
