541 
which the orbits of the electrons can make with the crystallografic 
plane under discussion. 
2) 
The annexed table gives =. calculated‘) for the three cases; in the 
last case once for a value r = 0,56.10—8 and once for r =0,81.10 Sc.m. 
Here the ratio between the numbers standing in the same column 
is only of importance. We have to remark that the spectra (002) 
and (024) disappear independently of the assumed value of r. Only 
to make also the spectrum (222) disappear we are bound to certain 
limits in the choice of r. 
Indices. | Br. D. and Sch. r =0.56.10 * |r—0.81.10" 
(11) eee Ae 2.9 5.8 
(002) | 0 0 0 0 
(022) | 36 4 0.61 7.8 
(13) | 18 0.34 1.64 3.55 
(222) OR NLG 0 0.038 
(004) BB te dle ed SAAD 9.0 
(133) 18 2 2.1 2042000 
(024) ost Hildo 0 0 
In calculating this table no account has been taken of the different 
factors’) that strongly affect the intensity of the expected spectra 
(mostly those of higher order). Because as yet all is quite uncertain 
and the foregoing speculations are very schematic, I thought it 
unnecessary to involve them in the calculations. The table however 
shows that especially the numbers of the fourth column do not more 
contradict the experimental data than those of the first®). From 
which we may conclude that for the present it will not be possible 
to draw a conclusion from the experimental data concerning the 
existence or non-existence of the connecting-rings. Perhaps here the 
study of the erystals of homologous elements (Si,Ge)*) may bring 
a decision. 
4) The first two columns are taken from D. and Scu. 
4) e.g. LORENTZ- and Depise- factor, see Marx Handbuch V, p. 581 af. 
5) See Brace |.c. and Degije and Scuerker l.c. 
*) Si seems to behave completely as diamond, cf. Desise and Sen. Phys. Z. S. 
(1916) p. 282. 
With Ge the number of connecting-electrons is already small compared with 
that of the nucleus-electrons. 
36 
Proceedings Royal Acad. Amsterdam. Vol XXII. 
