208 NATURAL SELECTION IX 
from the points in space indicated by the atomic centres, it 
is logical continually to diminish their size till they vanish, 
leaving only localised centres of force to represent them. Of 
the various attempts that have been made to show how the 
properties of matter may be due to such modified atoms 
(considered as mere centres of force), the most successful, 
because the simplest and the most logical, is that of Mr. 
Bayma, who, in his Molecular Mechanics, has demonstrated 
how, from the simple assumption of such centres having 
attractive and repulsive forces (both varying according to 
the same law of the inverse squares as gravitation), and by 
grouping them in symmetrical figures, consisting of a repulsive 
centre, an attractive nucleus, and one or more repulsive 
envelopes, we may explain all the general properties of matter ; 
and, by more and more complex arrangements, even the 
special chemical, electrical, and magnetic properties of special 
forms of matter.1 Each chemical element will thus consist of 
a molecule formed of simple atoms (or as Mr. Bayma terms 
them, to avoid confusion, “material elements”) in greater or 
less number and of more or less complex arrangement ; which 
molecule is in stable equilibrium, but liable to be changed in 
form by the attractive or repulsive influences of differently 
constituted molecules, constituting the phenomena of chemical 
combination, and resulting in new forms of molecule of greater 
complexity and more or less stability. 
Those organic compounds of which organised beings are 
built up consist, as is well known, of matter of an extreme 
complexity and great instability ; whence result the changes 
of form to which it is continually subject. This view en- 
ables us to comprehend the possibility of the phenomena of 
vegetative life being due to an almost infinite complexity of 
1 Mr. Bayma’s work, entitled The Elements of Molecular Mechanics, was 
published in 1866, and has received less attention than it deserves. It is 
characterised by great lucidity, by logical arrangement, and by comparatively 
simple geometrical and algebraical demonstrations, so that it may be under- 
stood and appreciated with a very moderate knowledge of mathematics. It 
consists of a series of Propositions, deduced from the known properties of 
matter ; from these are derived a number of Theorems, by whose help the 
more complicated Problems are solved. Nothing is taken for granted through- 
out the work, and the only valid mode of escaping from its conclusions is, by 
either disproving the fundamental Propositions, or by detecting fallacies in the 
subsequent reasoning. 
