io6 
PHYSICS: A. F. KOVARIK 
Proc. N. a. S. 
pertaining to the nature of 7-rays and X-rays, and also questions bearing 
on energy absorption and emission by an atom. For example it is important 
to know whether a spherical wave passing over matter will cause a simul- 
taneous ejection of electrons at different parts of the same wave front. 
To test this two independent counting chambers were placed at equal 
distances from the source of 7-rays but at various different relative posi- 
tions. One chamber registered the 7-ray effect audibly and the other 
optically. It was found that in no case were the effects produced simul- 
taneously. When the chambers were placed one behind the other the 
effects were also non-simultaneous. 
By varying the distance between one chamber and the source a con- 
firmation of the inverse square law was obtained. Using a chamber of 
some definite material with thin walls and increasing this small thick- 
ness of the walls the registered number of effects increased. When ma- 
terial of higher atomic weight was used the effect also increased. 
The first experiments mentioned can best be explained by assuming 
some corpuscular or ether-string theory and applying the law of prob- 
ability to the distribution of the radiations, but in view of the facts coming 
from crystal experiments it seems necessary to consider some spreading 
pulse theory. If we assume the pulses to spread out as spherical surfaces 
we must consider absorption of energy by an atom and also a possible 
trigger action — an action not in great favor in recent years. The fact that 
the counting chambers did not record the 7-ray effects simultaneously 
means that the electron or electrons ejected were not ejected simultaneously 
from the metal or air of the chamber; but since the electrons ejected 
have, presumably, equal velocities and, therefore, equal energies, the 
experimental result indicates that the individual electrons do not acquire 
the necessary quanta of energy at the same time. This suggests a possible 
storing up of energy. There are, however, reasons to believe that the 
energy stored up cannot be equal to the energy represented by the ejected 
electrons, and it would follow that some if not most of the energy of the 
ejected electrons must come from the interior of the atom and that the 
7-ray energy absorbed is only sufficient to perform the trigger action. 
Furthermore, it seems very probable that the particular electron to be 
ejected may have previously acquired, in some way, energy nearly sufficient 
to throw it out of balance which the 7-ray energy may suffice in doing; 
and it also seems probable that the more penetrating the 7-rays, i. e., the 
higher the value of v, the deeper is the electron which will be ejected by the 
7-ray. 
During the progress of these experiments, which were to include also 
the determination of the number of 7-ray pulses per second, per gram of 
radium, I received reprints of work done on this problem by R. W. Lawson 
and V. F. Hess^ at the Radium Institute in Vienna (where Mr. Lawson, 
although a civilian prisoner during the war, was permitted to continue 
