539 
4 a sing 
Taking into consideration, that « = , we find, if Brace’s 
relation 
2d sin p= nh 
is satisfied, 
2 rn 
Deden /(6) 
As is known the function J, is real for real values of the argument 
and oscillates between decreasing positive and negative limits and so 
behaves like a “damped” sinefunction. Here this means, that the 
phase-difference between the resultant beam and a beam reflected by 
the plane 64 is zero or 180°. The absolute value of (2) is always 
less than 1 except for the argument 0; the motion of the electrons 
therefore implies a decreasing of the intensity of the reflected Rönt- 
genbeam. The experiment requires, that the spectrum of the second 
order by reflection from 6 and 6’ disappears. This happens strictly if 
TUe REEL TER) 
since the plane 6 contains thrice as many electrons as 6’. 
The smallest value of /, which satisfies (4) and (3) for n= 2 is 
0,258 d. If we assume according to Brace d= 0,203.10 8 ¢.m., 
then /—0,524.10-§ ¢.m., which should give for the radius of the 
orbit of the electron »=0,56.10—-§ c.m., which value cannot be 
excluded for being impossible '). Here it is of importance that the 
relation (4) holds independently of the wave-length of the Röntgenrays. 
Now | do not intend to attach high value to this calculation of the 
radius of the orbit. Firstly because my supposition (uniform circular 
motion of the electrons) is too schematic, secondly it is not probable, 
that Desye and Scenerrer should have been able to ascertain an 
intensity which should remain for instance below a 100" of that 
of the spectrum of the first order. This gives in the above case for 
r all values between about 0,52 and 0,62.10—8 and also between 
0,70 and 0,81.10-® e‚m. Greater values of 7 are a priori improbable. 
Now the question arises if the existence or non-existence of the 
rings of connecting-electrons yet may be proved in the manner 
suggested by Dupre and Scuerrer. The spectra of higher order obtained 
by reflection from the octahedron-plane are not adapted for the 
purpose. Thus the spectrum of the 6" order should give a difference 
between the model with the connecting-electrons and that without. 
') If we only take account of the change of the two nuclei concerned vas a 
fourfold charge) and neglect all the disturbances, then according to Bour an orbit 
of one quantum and two electrons has a radius of about 0,75 10-8 ¢.m. 
