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and fixity of terms is a necessity when a new thought has to be adapted to an 
old language, and really this word “ energy ” is one that was only advanced, 
as it were, the other day. The word “ force ” is an old word, and one we are 
all accustomed to ; but we have here the new word “ energy,” used in an 
entirely different sense from what used to be its meaning ; and it seems to 
have been employed because some confusion was found to arise in the use 
of the old word “force.” My own view of the subject is that force is an 
inherent property of matter, like the affinities which all things possess. What 
is called chemical affinity is only one kind of affinity. I think that affinity 
is perhaps the most universal term by which to express the forces. It may 
possibly include gravitation, and the reason why two bodies approach each 
other may be that they have affinities causing them to attract each other ; for 
when the magnet attracts an atom of iron, the attraction is not all on one 
side. The magnet has the power of attraction ; but the little piece of iron 
attracts the magnet as truly as the magnet attracts the particle of metal. In 
like manner, when it is said that the sun attracts the earth, it is equally true 
that the earth in a proportionate degree attracts the sun. In fact it may be 
said generally that all particles of matter have an attraction for all other 
particles of matter. This of course deals with masses. If you go to chemical 
affinity, there must be that degree of propinquity which brings molecules 
within the range of their mutual action. You cannot deprive any body or 
any substance of its affinities. Oxygen will attract carbon, and so on, and 
certain combinations will be formed by all the different chemical elements 
which have affinities for each other. These are inherent properties which 
they cannot lose. The conditions may be altered, but the affinities cannot be 
altered. This is a point on which l)r. M‘Cann agrees with me ; but with 
regard to the conservation of energy it is really very difficult to grasp the 
subject at all so as to form a clear idea of it, for it may be said to be almost 
in its infancy. We have been shown that the greatest intellects of the age, 
some of whom are alluded to, have actually been guilty of great confusion 
of thought, or at all events, of language. It does not seem to be always the 
case that confusion of language is at the same time confusion of thought. 
In a work entitled “ Habit and Intelligence,” by Mr. Murphy, of Belfast, 
the writer accuses Mr. Justice Grove of some want of precision in his 
language, and quotes a passage in which Mr. Grove asserts that gravity, or 
motion of some kind, was transmitted or converted into chemical affinity, 
and he apologizes for saying this by telling us that he does not mean to 
accuse Mr. Grove of confusion of thought, because the nomenclature of the 
subject is not understood, and people do not always think of using the 
right word exactly in the right place. These two words “force” and 
“ energy ” are so like each other in the way they are used, that it is very 
hard to employ them without making mistakes. For instance, the only 
source of energy is force, and yet energy cannot always be reconverted into 
force. Gravity, which always exists between masses of matter, is force, 
this may give rise to energy ; but when an object set in motion by gravity 
reaches the earth, the force of gravity remains, whilst that form of energy 
