421 
11, Scroope Terrace, 2Lst March, 1877. 
Dear Professor Birks,— I have read your lecture again, but am unable 
to say more than to thank you for the clear way in which you have set forth 
the proper use of language with respect to motion. Whenever we begin to 
subject the primitive phraseology about natural events to scientific analysis 
our language becomes stiff, and cramped, and unpoetical, because it is built 
upon a framework of new and rough scientific hypotheses which have not yet 
been settled into their proper places even by experts, and which to the mass 
ot mankind are nothing but jargon. In this state of things, poetry and science 
ar ® supposed to be in opposition to each other ; and if science is admitted 
deficient in grace, poetry is suspected to be indifferent to truth. 
But as soon as the scientific analysis has been made in a satisfactory man- 
ner in any particular subject, it becomes evident that the primitive phraseo- 
logy which stood the test of experience for so many thousand years is really 
the most scientific as well as the most elegant, and that it does not convey 
any false impressions to those who have studied the matter, any more than 
to those who have not. 
Thus, our phraseology about the thermal phenomena was put into con- 
fusion last century by those who said there was no heat in the fire, nor any- 
where else, except in our minds. 
We now agree in language better with our remoter ancestors when we 
measure the quantity of heat given out by a pound of coal, and we never 
think of confounding what we are measuring with a sensation. 
Yours, very truly, 
J. Clerk-Maxwell. 
I have also received the following letter from the Plumian Professor 
Astronomy at Cambridge : — 
March 31, 1877. 
I thank you for sending me a copy of Professor Birks’s paper “ On the 
Bible and Modern Astronomy.” I have read it through, and can say of it 
generally that I consider it to be an able contribution towards settling the 
question of the mutual relation between the revelations of Scripture and the 
discoveries of modern physical science. The only particular remark it occurs 
to me to make is, that I cordially agree with what Professor Birks has said 
in art. 17 of the essay, where he speaks of “ the looseness of thought which 
sets down every unproved hypothesis started by physical philosophers as a 
firm and established fact of science,” and condemns “ the easy credulity with 
which some Christian men are ready to take up the newest scientific guesses, 
and not only sacrifice to them a considerable part of their own faith in the 
Bible, but exhort others to do the same, as a triumph of Christian candour 
over the blindness of prejudice.” I think, too, that Professor Birks has well 
exposed the inappropriateness of the view taken by Canon Titcomb (in art. 
24 of his paper “ On Certain Magnitudes in Nature”) as to the bearing of 
Madler s unproved conclusion, that the star Alcyone of the Pleiades is at 
the centre ot gravity of the stellar system, upon the interpretation of Job 
xxxviii. 31. 
J. Challis. 
