294 
ON CHEMISTRY. 
rejecting “all periphrastic expressions,” he distinguished “ the cause 
of heat, or that exquisitely clastic fluid which produces it, hy the 
term Caloric." —( Calor — latin—H eat.) 
We may admit these conjectures—or with Dr. Young, the philo¬ 
sopher, we may doubt the theory of the modern school. He be¬ 
lieved that the production of heat by friction, appeared to afford an 
unanswerable confutation of the whole doctrine. “If the heat is nei¬ 
ther received from the surrounding bodies, which it cannot be with¬ 
out a depression of their temperature , nor derived from the quantity 
already accumulated in the bodies themselves, which it could not be, 
even if their capacities were diminished in any imaginable degree, 
there is no alternative but to allow that heat must be generated by 
friction : and if it is generated out of nothing , it cannot be matter, 
nor even an immaterial, or semi-material substance.” 
Difficulties surround the subject on every hand; and to remove 
them, I conceive we can only apply—philosophically—to the source 
of heat; for source it has but one. The sun is the object to which 
we must turn our minds; and therein we shall, at least, obtain some 
solid cause for satisfaction. We may not be able to conjecture what 
this glorious luminary really is,—and we may find ourselves at a loss 
to conceive the nature of his substance, or what is the agency bv 
which he radiates light and heat to the planetary system : but still, 
we feel assured that we have reality before us—that we see an efful¬ 
gent orb, which our senses assure us is ever pouring forth streams 
of light and life. Now, from the beginning of time, the sun has sent 
his beams to the earth, and though, we have fair reason to conclude 
that they produce no positive heat till they strike upon a decompo¬ 
sable reflecting substance, yet the beams are the operative, efficient, 
cause of heat. From the period of the first ray to the passing mo¬ 
ment of time present, not a particle of light has been wasted, or ex¬ 
tinguished : the traceable analogy of all nature confirms, I think, 
this assertion. The light not reflected, is absorbed by all substances 
upon which it impinges, and effects electro-chemical decompositions, 
becoming itself perhaps decomposed. The heat which is mani¬ 
fested by fermenting substances, by chemical mixtures, by acts of 
friction, and which is felt, but not seen, is an effect produced by the 
play of affinities operated by the agency of absorbed solar light: the 
whole theory of latent heat is based upon this fact. 
That which at any time, or by any means, becomes revealed, 
must have existed, must have had an origin. 1 ask the candid 
reader then, whether the emanations from the sun, the effulgence 
which lias beamed upon the earth for thousands of years, do not offer 
