54 Evolution and Devolution of the Elements. 
it is highly probable that an exact number of proto-boron 
atoms will form one helium atom. Consequently, the atomic 
weight of proto-boron must be T33 or 2. But proto-boron 
is of necessity heavier than proto-beryllium, and consequently 
its atomic weight must be 2. Therefore, we see that the 
atomic weights of the four primary atoms form an harmonic 
series, namely 4/4, 4/3, 4/2, 4/1, which is interesting in con- 
nexion with Newland's original idea of octaves. 
!So little is known of the substances to which the various 
emanations give rise, that we will not hazard any suggestions 
regarding them. 
The last case before us is that of uranium, the simplest of 
all the radioactive elements. In this case, as with thorium 
and actinium, we have a heavy atom, heavier than radium, 
belonging to the carbon family. When one a particle has 
been expelled, uranium, like thorium, changes into uranium X, 
but uranium X is very different to thorium X. Instead of 
giving out a particles it gives out ft and y particles, and does 
not decay into any emanation. 
The mention of ft and y particles opens out an entirely fresh 
phase of radioactivity, and to explain it fully we should have to 
enter into many new details, which in themselves form sufficient 
material for a separate paper. However, as we mentioned 
at the commencement of our paper, the space at our 
disposal necessitated the omission of many astrophysical facts 
bearing directly upon the subject with which we have dealt, 
and now again we are constrained to pass over a fuller treat- 
ment of this important branch of radioactivity. 
To recapitulate, our conclusions concerning the periodic 
law and radioactivity are direct deductions from stellar 
observations, and many other little understood facts connected 
with matter find an explanation in the same source. We 
chose the periodic law and an outline of radioactivity as 
being perhaps the most typical examples of this theory, but 
we hope to give others at no distant date, and also a more 
detailed account of the astrophysical observations which gave 
rise to this paper. 
In conclusion, we wish to express our most hearty thanks 
to Professor E. C. C. Baly and Mr. H. E. Watson for their 
valuable assistance, and the kind interest they have taken in 
this paper. 
Explanation of Diagram (Plate VII.). 
The diagram on Plate VII. represents what we believe to be the 
structure of elements of typical groups. Circles drawn at wide 
distances from each other (2 mm.) indicate regularity of structure, 
i. e. successive elements have the same valencv. Circles drawn 
