1822.] Cis Reply to D. 201 
must contain no errors, or e77'0r must be truth, and wrong, right.” 
Thus, by apprehending one piece of nonsense, and assuming 
“ of course”? another, he triumphantly concludes that there are 
absurdities in the propositions, of which they do not in fact 
contain the slightest trace. The intelligence and fairness of 
such observations are just equal. 
His next criticism is found in the following extract: “ Allud- 
ing to the loss and developement of heat in the changes of states, 
C. objects to Mr. H.’s theory of heat by motion, because heat 
may for a time become imperceptible, and again be developed 
without being destroyed. ‘ If, therefore,’ says C. ‘ heat and 
motion be identical, motion cannot be destroyed, which the 
experience of every day tells us is untrue.’ Here C. would 
plainly charge Mr. H.’s thecry as being incompetent to explain, 
nay, as being repugnant to the phenomena of latent heat. Now 
observe ‘ Mr. H.’s Theory of the Changes of State and the 
Concomitant Phenomena,’ in which the subject C. alludes to is 
copiously explained, was published in the Annals for October ; 
C. in his ‘ Observations,’ dated nearly a fortnight afterwards, 
tells us he had seen this very number of the Annals, and of 
course this very explanation, for the want of which he gravely 
tells the world Mr. H.’s theory is defective.” However unjusti- 
fiable it may have been in D. to misquote the expressions of Mr. 
Herapath, yet as it was for the purpose of supporting his theory, 
the injury was not to Mr. H. but to D.’s own character. Butin 
the foregoimg paragraph, D. not only states that 1 made asser- 
tions and charges which I never did make, but even by inverted 
commas, as though they were literal extracts, ascribes to me 
expresstons which I never used, and a meaning which | never 
intended ; and that for the express purpose of raising the impu- 
tation that | had stated what was unsupported by fact. Itis not 
true that I objected to Mr. H.’s theory of heat by motion, 
“because heat may for a time become imperceptible, and again 
be developed without being destroyed.” I did not charge Mr. 
H.’s theory “as being incompetent to explain,” or “as being 
repugnant to the phenomena of latent heat.” I did not object, 
nor in any way allude, to that part of Mr. H.’s theory, however 
erroneous I may have thought it; consequently, 1 never did 
“ tell the world that his theory was defective,” for want of any 
explanation in relation to it. Every one of those assertions of 
D. both in substance and effect, are utterly untrue. This will be 
clearly proved by the paragraph itself, to which he refers. It is 
the following: ‘‘ Experiment has clearly shown that caloric, or 
the immediate cause of heat, whatever it may be called, cannot 
be destroyed. However, under particular circumstances, it may 
become for a time imperceptible, it can be again developed, and. 
so be shown to have continued its existence ; if, therefore, heat 
and motion be identical, motion cannot be destroyed. This, I 
apprehend, the experience of every day, in addition to mathema- 
