1276 
Taking into consideration that nN represents the total number of 
the molecules struck by radiation ®, then we see that the intensity 
of the maxima is proportional to 
NN 
so that the spots are the more intense according as they are 
caused by planes in which the number of molecules pro unit of 
plane is greater.) We can even to some degree extend what was 
observed above, so as to come to a conclusion which perhaps can 
be controlled by experiments. Take an z-axis in the direction of 
the normal of the planes, then « will pass through the values 
+ Iq + U + kl, ete., in which the same positive and negative 
value ought to be taken for y, when the origin is chosen in the 
centre of the plate. For each value of x the part cut off from the 
plane by the incident beam can be calculated. Be this part S,, the 
number of molecules pro unit of plane is r/,, the contribution to 
the intensity of the plane S,, therefore 
Dd oe 
and the total intensity is therefore v* ln’ = S,’, for which we may 
approximately write 
p? fs de. 
By applying this formula in different cases, we may come to a 
further trial of the theory ; however, we do not yet possess the necessary 
photometrical experimental measurements. The intensity of the maxima 
now under consideration is greater than that of the “two-cone” 
maxima of Laur (of the order 10° times as great), it is, however, of 
the order 107 times as small as that of the 3 cone maxima of LAUE. 
However, the experiment forces us to such a degree to accept the 
explication by reflection, that probably in no other way than in the 
one described above the photograms may be explained, as I will 
show below. 
We may still observe, that in the consideration as given above, 
the molecules are assumed to contain only one electron. We can, 
however, easily get rid of this supposition by multiplying N and 
» by s, where s is the number of electrons pro molecule. Perhaps, 
by taking this into account, we may derive an estimation of the 
proportion of the numbers of electrons pro molecule in different erys- 
tallised matter. 
1) We may here observe, that by this we have the means of comparing the 
numbers NV, in matter with given density, for planes that are struck by equal 
radiation under similar circumstances, 
