14 
Such words show you far better than any of mine could, the 
difficulty of this form of scientific belief. If Mind be evolved 
from Matter there can be but one substratum, not two; all the old 
ideas must be incorrect, and this one substance possesses at the 
same time two sets of opposite properties. I think we must allow 
that this is but making a mystery more mysterious still. We shall 
require a new definition of Matter, the nature of which however has 
not yet been determined. 
MOLECULES AND THEIR MOTIONS. 
A mass of matter of any kind is supposed to be made up of a 
number of minute bodies which are called molecules. We define a 
molecule as the smallest possible particle of a substance that can 
exist alone. It is in itself compound, often exceedingly complex, 
being composed of still minuter particles called atoms; but being 
the smallest particle of a substance that we can even think about ; 
the moment a molecule is broken up by chemical action its nature 
is changed ; it enters into new arrangements and is no longer the 
same substance. No person has ever yet seen a molecule, in all 
probability no one ever will; the minutest grain visible under the 
most powerful microscope contains thousands of them. Yet in 
spite of this great disadvantage our scientific guides tell us they 
have been approximately measured; and the diameter of one 
cannot be less than the 500 millionth part of an inch. The number 
of them in a cubic inch of air at a freezing temperature would be 
represented by the figure 3 with twenty ciphers after it, while a 
drop of water, in which they would necessarily be packed more 
closely together, contains a number represented by 100 followed 
by twenty-four ciphers. The physicist, like the astronomer, deals 
with numbers infinitely large, but he also deals with sizes infinitely 
small. Now these particles are never at rest, they are always in 
rapid motion even in the densest solid, but necessarily moving 
within narrow limits; so that evenif we accept inertia asa pro- 
perty of matter in the mass, it does not appear to be a property of 
its constituent molecules, and therefore it is not an essential pro- 
perty of matter, though our text books have always taught us that 
it is. And again if we grant that the molecular movements are the 
consequence of some primal force originally acting on them, but not 
now, do we not get perpetual motion, which we are told is anim- 
possibility ? In liquids the limits of vibration are wider than in 
solids, but the greatest molecular freedom is found in bodies in 
the gaseous condition, and here the rapidity is enormous. Accord- 
ing to accepted calculations and experiments the particles of 
hydrogen gas at a freezing temperature are moving about at the 
