3 
, 
iq 
Dr. Hare on the Cause of Heat. 147 
votally different from any it can itself possess, and at the 
same time capable of such wonderful effects, as are produ- 
ced by the agency of steam. Is it to be imagined that in 
particles whose weight does not exceed a few ounces, sufli- 
cient momentum can be accumulated to move as many tons ? 
There appears to me another very serious obstacle to this 
explanation of the nature of heat. How are we to account 
or its relation in vacuo, which the distinguished advocate 
of the bypothesis has himself shown to ensue ? There can 
be no motion without matter. To surmount this revs: 4 
he calls up a suggestion of Newton’s, that the calorific v 
brations of matter may send off radiant particles, which Stee 
their own momentum in communicating vibrations to bo- 
dies dere from wise, whence they emanate. Thus ac- 
siders heat as material, will apply equally against the exist- 
ence of material calorific emanations. ‘That the cannon, 
heated by friction in the noted experiment of Rumford, 
would have radiated as well as if heated in any other way, 
there can, I think, be no doubt; and as well in vacuo, as the 
pe ae by Sir Humphrey i in a similar situation. 
mission in this way would have been as inexhaustible as 
by ‘ne conducting process cannot questior Why 
then is it notas easy to have an inexiinstible supply of heat 
as a material substance, as to have an inexhaustible ply 
of radiant matter, communicating the vibrations in wbick he 
a heat to consist ? 
e see the same matter, at different times, rendered sel 
attractive, or self-repellent ; ; now cohering in the solid form 
with great tenacity, and now flying apart with explosive vio- 
ce in the state of vapour. Hence the existence, in na- 
ture, of two opposite kinds of ceases between particles, 
is self evident. There can be no property without mat- 
ter, in which it may be inherent. “Nothing can have no 
property. a question then is, whether “these opposite 
erti n belong to the same particles. Is it not evi- 
dent, that the same particles cannot, at the same time, be 
self-repellent, and self-attractive ? Suppose them to be sO, 
one of the two properties must predominate, and in that case 
we should not perceive the existence of the other. It would 
