Evolution and Devolution of the Elements. 53 
are probably not deranged during the transformation, since 
none are given out ; hence we may assume that the only 
change which takes place is in the protons, and that this is 
of the nature of polymerization. Consequently, an integral 
number of radium protons must form the atom of helium, 
and if this be so, the atomic weight of the proto-bery Ilium 
proton must be 1'33 or 2, so that either three, or two of them, 
unite to form helium. 
Now the value given by our formula in the last section, 
for the atomic weight of proto-beryllium, was 1*3 ; moreover, 
we are about to show that there are reasons for believing 
that the atomic weight of proto-boron is 2, and consequently 
we must assume that the atomic weight of proto-beryllium 
is 1*33. We will now consider the behaviour of thorium 
and actinium. These elements resemble each other in their 
method of disintegration, and consequently they may be 
treated together. 
By thorium, we mean the element which gives rise to 
thorium X, its emanation, and its active deposit. 
In the cases of thorium and actinium, we have two heavy 
atoms, in all probability heavier even than radium, and com- 
posed of proto-boron protons. When one of these particles 
is expelled, the atom, as in the case of radium, will try to 
assume a more stable form. Now since the rare earths are 
all formed by the preceding elements adding a trivalent ring, 
it appears that such a ring is at any rate a configuration of 
great stability, and it should not surprise us if an element 
when disintegrating should form a stable derivative with a 
trivalent ring, and that this is the X derivative. In other 
words, thorium and actinium will have been transformed into 
thorium X, and actinium X, with trivalent outer rings, but 
they will have the same sized a particles, as their protons 
have as yet undergone no change. If this is the case, we can 
see why thorium, actinium, and uranium should form 
thorium X, actinium X, and uranium X, while radium should 
be immediately transformed into its emanation For the 
weight of radium being below that of the element which 
would occupy the last position of group III., radium in the 
process of devolution cannot turn into this element, but goes 
at once into the helium family. The other elements have a 
higher atomic weight, and do form this element as they decay. 
This involves the fact that all the X's are the same substance, 
and we hope at a future date to give reasons for believing 
that this assumption is correct. 
The X elements when formed will give off an a particle, 
and, like radium, become members of the helium family. By 
a method of reasoning similar to that in the case of radium. 
