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force and motion are definite terms which he used in a definite sense, but he 
complains of the confusion attaching to the term “ energy,” and incidental 
to the use of that tertium quid. Another point on which they are at one 
seemed to be urged against Professor Birks : Mr. Brooke asks, “ How can 
you conceive a particle of motion 1 ” But he has fastened upon one part of 
a passage and left the rest ; for Professor Birks himself says, “ How can there 
be such a thing as a particle of motion 1” The passage runs, 
“ What other power compels the blind Titan to weary itself in these 
ceaseless transmigrations ? We can easily conceive one body, endowed with 
active power, pushing or pulling, seeking or avoiding, another. But how 
can we conceive a particle of motion, which is not a thing that moves, 
but an abstract quality or relation, pushing or pulling another particle of 
the same force.” 
I think the difference between Mr. Brooke and the Professor is divergence 
rather than antagonism. No doubt there are some points of antagonism, but I 
think it is in the interest of the pursuit of truths that we have not yet 
reached, that we should minimise rather than magnify divergencies on sub- 
sidiary points. Let me give two illustrations of what I mean. I cannot 
quite take up arms against this paper, and condemn it for being too clear. 
I remember the remarks of Archbishop Whately. Mr. Brooke gives us a 
German apophthegm, but I do not think it applies to Professor Birks and his 
“ garb of folly.” He does what Socrates did in his day, and tries to take 
the power from those who make the worse appear the better reason. Whately 
talked of a certain class of minds who never were satisfied with anything 
sufficiently clear to enable them to see to the bottom ; only stir up the mud, 
and then they would cry, “ How deep that is ! ” I thank the man who lets 
the sediment go away and gives the clear stream, and therefore I am obliged 
to Professor Birks. If the doctrine of the persistence of force is as I 
understand it, and as I know it to be expressed by Professor Huxley and 
Dr. Tyndall, it is the doctrine of the broomstick without the possibility of 
the existence of another power outside to interfere with it. That is the 
question at issue, and we ought not to allow such a doctrine to take a place to 
which it has no right, or to usurp a place as an established truth, before it 
has given credentials and stood its ground successfully. There is a German 
author who gives us an illustration on another subject. He says, “You 
talk of Providence, and of Divine government, and Divine action, and so on. 
Will you tell me what room there is for it in the world ? You are on the 
sea-shore, where there is a particular grain of sand ten or fifteen feet from 
high water-mark. Perhaps Divine Providence, you think, might have taken 
that grain of sand and let it be half an inch nearer or further from high 
water-mark. Do you know what it would involve if you prayed to God or 
to Providence for such a result, and your prayer was answered I That par- 
ticular grain of sand is where it is because the force of the waves has been 
exact and definite, and that has been the result of the force of certain storms 
that have raged, and they have depended upon clinmtal conditions and 
atmospheric changes, and they in turn have depended on the nature of the 
