30 Messrs. A. C. and A. E. Jessup on the 
which silicon was evolved should be found in very large 
quantities in the nebulae. Now the element whose wave-length 
is 5007 is far the most abundant of the four protons formed in 
the nebuloe, and consequently, we consider that this element 
gives rise to carbon and silicon, &c. (3) Starting from lithium, 
in the whole scheme of evolution there is only one point where 
the evolution sub-divides into both direct and indirect series 
of derivatives. This occurs, as we have shown, in the case of 
the element silicon, which gives rise to one direct and ten 
indirect derivatives, and applying our hereditary principle, 
we would say that this tendency to sub-divide is due to the 
fact that such a sub-division had previously taken place, and 
would therefore argue that carbon and silicon are themselves 
indirect derivatives from one of the protons. For this reason, 
therefore, we think that the position of the element 5007 
cannot be at the head of the carbon and silicon groups. 
(4) Moreover, except in the case of the six central groups, 
the discussion of which, owing to their exceptional character, 
we for the moment defer, there is no case in the whole table 
of an element giving an evolution product with a valency less 
than its own *. For these reasons we put the proton with 
wave-length 5007 at the head of the trivalent groups of 
elements boron, aluminium, &c, and we are only left with 
the position at the head of the alkaline earth metals for the 
remaining proton with wave-length 4959. Since this element 
has without doubt a smaller atomic weight than that of the 
element with wave-length 5007, this position seems perfectly 
justified. For convenience we venture to suggest the 
names of proto-beryllium and proto-boron for these two 
elements. 
Since drawing up this Periodic Table, a paper has appeared 
by Messrs. Cuthbertson and Metcalfe (Phil. Trans. 1907, 
Ser. A, vol. ccvii. p. 135), in which they give a Periodic 
Table of the Elements, which, so far as it is carried, is 
practically the same as the one in this paper. These authors 
have deduced their Table from observations upon the 
refractivities of the elements, and we venture to think that 
this gives considerable support to this particular form of the 
Periodic Table. 
In our new form of the Periodic Table it will be observed, 
as already pointed out, that a large number of elements 
appear as having been formed from silicon. Now, to explain 
their position, and in fact, the actual structure of all the 
* By our theory of the indirect evolution process, the indirect products 
must have a greater valency than the parent element (see below p. 33). 
