122 Professor Adams on the Theory of the Thermometer. 
for as they can neither see, nor touch, nor weigh caloric, 
they are obliged to strip it, at least as far as our senses are 
concerned, of all the most apparent properties by which we 
are sesured of the existence of matter; such as extension, 
impenetrability, and gravity. This opinion, is supported 
by considerable eee though perhaps not sufficient to 
give entire satisfa ctio 
ty with the eee intensity of the heat. In fluids and 
i the particles are conceived to have a motion round 
eir own axes. Temperature, therefore, with them, will 
pepe with the velocity of the vibrations, and increase of 
capacity will be bac by the motion being performed 
rotary motion.* The most prec ae advocate of this 
hypothesis, of late years, is Sir H. Davy. A detailed ac- 
count of his views may be found in his ‘ Elements of 
Chemistry.” Since, in the exact sciences, the opinion of 
no man is better than the reasons which he gives for it; 
with perfect respect for the talents of this illustrious chem- 
ist, and with the greatest admiration of his splendid discoy- 
eries, it is probable, that his hypothesis will never be ex- 
tensively received. Indeed, the idea, that all the facts 
with which we are acquainted respecting heat, can be made 
to depend on motion of any kind, is perhaps scarcely less 
than inconceivable. It is difficult, to understand, how this 
of a reductio ad absurdum, has been constructed by 
Dr. Hare, and will doubtless be recollected by the readers 
of this journal. 
Another class of philosophers, attaching themselves to 
neither of these hypotheses, limit themselves to admitting 
the facts common to both, and consider the term caloric, 
as the name of a cause whose nature is not known any 
further than, that it gives us the sensation of heat, and pro- 
duces peculiar effects upon the substances around us. 
* Brande, Manual of Chem. 1. 248. 
tVol. IV, 142. 
