652 
error in the value of 6 for the bromate is about 0,01 of the cell- 
edge, the accuracy of the other parameters is much smaller *). 
In the calculation of the intensities we have taken into consider- 
ation besides the structure factor’) only the number of planes and 
the Lorentz-factor. We thus have neglected the absorption in the 
rod, the temperature-factor and the polarisation-factor. This is allowed, 
when only we compare the intensities of very close neighbouring 
interference fringes. 
Starting from the assumption that the X-rays are deflected for 
the greater part by the electrons, we calculated the intensities under 
the following simplifying assumptions. 
Round the sodium point we place 10 electrons (monovalent positive 
ion)*); the weakening of the coöperation by mutual interference is 
neglected. Round the halogen particles we place in the cases A, B, 
C, and D of the columns 3, 4, 5, and 6 of the tables III and IV 
respectively 12,18, 12, and 10 electrons for the chlorate and 30, 36, 30, 
and 28 electrons for the bromate, while again the same neglections 
were made; in the same way for an oxygen particle resp. 10, 8, 
6, and 2 electrons. All this is based upon the following suppositions : 
in case A: pentavalent positive halogen-ions and bivalent negative 
oxygen atoms; 
in case B: monovalent negative halogen-ions and oxygen-atoms ; 
in case C: binding of oxygen in the halogenate-ion by a ring of 
four circulating electrons, of which two are derived from the oxygen- 
atom and two from the halogen-atom. The interference-effect by these 
binding-electrons has been neglected ; 
in case D: binding between halogen and oxygen, where the effect 
due to the total outer electron rings, to which the binding electrons 
belong, has been neglected. 
From the tables III and IV we see that the agreement between 
the calculated and observed intensities is good from which of these 
suppositions we may start. 
1) "This must be ascribed to the fact that the displacements of the Br-particles 
can only be very small when their influence on the interference-result shall be 
compensated by displacements of the other particles. This is the case to a much 
less degree for the Cl-particle because of its low atomic number. Therefore we 
cannot give a limit of the accuracy of the parameters either for this particle or 
for the O- and Na-particles. 
4) In the calculation of the structure-factor we took into consideration, that for 
planes with three unequal indices for the symmetry of these crystals this factor 
depends on the succession of the indices. Comp. W. H. and W. L. Bragg, Le 
p: Fol, 
3) P. DeBije and P. SCHERRER, Phys. ZS. 19 (1918), p. 474. 
