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him that we do not wish to unite the ideas of force and its 
destruction, but of motion and its cessation, which, in our 
unphilosophic minds, are very closely united.* 
34. We must do Mr. Spencer the justice of saying that he uses 
in one place the phrase “persistence of force ” with a meaning 
differing widely from the continuity of motion or energy, but 
with a meaning shared, I will venture to say, by no other writer 
on the subject. “Thus by the persistence of force,” he says, 
“ we really mean the persistence of some power which transcends 
our knowledge and conception. The manifestations, as occur- 
ring either in ourselves or outside of us, do not persist; but 
that which persists is the unknown cause of these manifesta- 
tions. In other words, asserting the persistence of force is but 
another mode of asserting an unconditioned reality, without 
beginning or end.” As the only reality answering to this 
description is God, Mr. Spencer asserts, and in this we are at 
one, that amid all changes, all beginnings, and all endings, 
there is one great Reality, the same yesterday, to-day, and for 
ever, the “ I AM.” But to call God’s unchanging existence 
the persistence of force is not the ordinary usage of language. 
It would be well, however, if all students of nature remembered 
the great fact, that the one force of the universe is the will 
of God, and that though heaven and earth may pass away, one 
jot or tittle of that will can never pass till all be fulfilled. 
35. From what has been already advanced, it will be at once 
evident that the Conversion of Forces is an important element 
in the hypothesis we are combating. It is very clear that 
motion ceases to exist as light, heat, or sound ; but, if it still 
exist as motion, it must be in some other mode. One mode 
called by one name, — as heat, for example, — becomes another 
mode, we are told, called by another name, such as light. We 
must understand clearly that it is conversion, and not condition, 
which is insisted on, at least by Dr. Tyndall and others. One force 
being the condition of the existence of another force, is a very 
different thing from one force becoming another force. The 
former we readily assent to ; but about the latter we are in very 
considerable doubt. It may be true ; but we think it still 
needs further proof. We are, however, in this safe position in 
* While we are compelled to differ from Dr. Tyndall on these theoretic 
points, we would express our unqualified admiration of his great abilities as 
an experimenter, and our sincere gratitude to him for making known the 
results of his investigations, in language so beautiful, clear, and precise as to 
captivate while he instructs ; and win students to the study of nature, who, 
but for him, might have gone to the grave caring nothing for God, and less 
for His works. 
