540 
Dr. Hans Geiger on the Irregularities in 
deflexion electrometer, suggests that the effect may be due to 
an exceedingly small and rapid change in the ionization 
itself. E. v. Schweidler* has in a special paper drawn 
attention to the fact, that according to the disintegration 
theory certain irregularities in the radiation from radioactive 
substances are to be expected. He calculates from the laws 
of probability that these irregularities should under certain 
conditions be within the limits of measurement. K. W. F. 
Kohlrauschf made some experiments to test the accuracy of 
the theory of v. Schweidler. A discussion of his results 
will be given later. 
In the course of some experiments, my attention was 
attracted by the impossibility of obtaining a steady balance 
of two opposite ionization currents due to the a rays. A few 
experiments will now be described which I have made to test 
the cause and the magnitude of these irregularities. 
It was of importance first to prove whether the effect was 
due to a real variation of the intensity of the radiation or to 
some secondary effect which might be eliminated. For this 
purpose, the following experiment was made : — Two ionization 
vessels, A and B, were arranged as shown in fig. 1. Between 
Fig. 1. 
+zoc>rf 
1 
B 
■2,ooy„ 
4- 
them, and insulated from them by the ebonite plugs £, c and 
the guard-rings g and 7i, was fixed a piece of aluminium foil D, 
which was connected with an electrometer of the Dolezalek 
* E. v. Schweidler, Cong-res international pour l'etude de la radiologic 
et de l'ionisation, Liege 1905. 
t K. W. F. Kohlrausch, Wien. Ber. 1906, p. 673. 
