94 
5. This passage is calculated to convey the idea that my 
Essay professes to give proofs of the mechanical theory of 
heat. But that Essay does not profess to give a single proof 
of that theory. It is entitled, “ Outline of the Theory of the 
Mechanical Action of Heat it gives a sketch of the general 
principles and results of that theory only ; and for the proofs, 
it refers to published detailed accounts, by various authors, 
of experimental researches, and calculations founded on the 
results of those researches, the whole of which published 
accounts are in the Library of this Society. 
6. The proofs of this, as of every other physical theory, 
consist in a mass of experiments and calculations, which 
cannot be condensed within the limits of a brief popular 
Essay ; and in order to examine and test those proofs, it is 
necessary to go to the fountain-head of information ; that is, 
to the detailed accounts of calculation and experiment. 
7. As to defective and erroneous quotations, I have in the 
first place to point out the following. The words in the 
genuine passage, whose omission in Mr. Dyer’s quotation has 
the effect of materially altering the meaning of the passage, 
are enclosed in square brackets, thus : [ ]. 
The Genuine Passage. 
5. Threefold Effect of 
Heat. — The communication 
of heat to a substance pro- 
duces [in general, three kinds 
of effects (setting aside chemi- 
cal, electrical, and magnetic 
phenomena, as being foreign 
to the subject of the present 
paper) :— ] 
1st, An increase of tem- 
perature and expansive pres- 
sure; that is to say, an 
increased tendency to the 
communication of heat to 
The Quotation. 
v Mr. Ilankine states “ that 
heat produces an increase of 
temperature and of expansive 
force in bodies ; that the 
change from the solid and 
liquid states to the gaseous 
state is accompanied by an 
increase in volume ; that heat 
which produces those effects 
is known by the name of 
sensible heat, as retaining the 
form of heat, and in short 
making the body hotter.” 
