Evolution and Devolution of the Elements. 21 
There are now ten elements lying between these limits, 
viz., vanadium, chromium, manganese, iron, nickel, cobalt, 
copper, zinc, gallium, and germanium ; and we must consider 
all these to be derived from silicon by some indirect process 
of evolution. It may be pointed out here that by the term 
" A direct process of evolution," we mean one by which an 
evolution product is obtained of the same valency as its parent 
or immediate antecedent element in the scale of evolution. 
Conversely, " indirect evolution " produces elements of 
valencies differing from that of the parent element. 
Now the next highest elements to germanium in order of 
atomic weight are arsenic, selenium, bromine, krypton, 
rubidium, and strontium ; but these undoubtedly belong to 
the families of nitrogen, oxygen, fluorine, helium, lithium, 
and beryllium respectively, and so may be considered as the 
direct evolution products of these families. The next four 
elements again are yttrium, zirconium, niobium, and molyb- 
denum, and these will fall naturally under scandium, titanium, 
vanadium, and chromium respectively, a fact which is in 
absolute agreement with the relative chemical properties of 
the families concerned. 
We are now in a position to draw up a Periodic Table 
modified from that of MendeleefE so far as to embody our 
conclusions, and such a table is shown opposite. 
Leaving, for the moment, the question of the four protons, 
hydrogen, proto-bery Ilium, proto-boron, and helium, we have 
clearly eight elements standing at the head of eight very 
strongly characterised families, viz., lithium, beryllium, boron, 
carbon, nitrogen, oxygen, fluorine, and neon. By direct 
evolution these eight elements give rise to the next eight 
elements in order of atomic weight — sodium, magnesium, 
aluminium, silicon, phosphorus, sulphur, chlorine, and argon. 
The question of argon having an atomic weight greater than 
that of potassium has already been mentioned. Following on, 
we have potassium, calcium, scandium, and titanium, which 
belong to the first four groups of the table. After titanium, 
we have the ten indirect derivatives of silicon which we have 
dealt with above, and we therefore place these in a hori- 
zontal row between the carbon and the nitrogen families. 
The next ten elements in order of ascending atomic weight 
following germanium, viz., arsenic, selenium, bromine, 
krypton, rubidium, strontium, yttrium, zirconium, niobium, 
and molybdenum, fall perfectly naturally in the consecutive 
families as already pointed out. The next vertical column 
after molybdenum is headed by manganese ; from a con- 
sideration of Mendeleeff's table, it is quite evident that 
