Conversations on Chemistry, V. 1-2 / In Which the Elements of that Science Are Familiarly Explained and Illustrated by Experiments

by Mrs. Marcet

EMILY.

Of this difference we have very striking examples before us, in the tin vessel of water, and the concave mirrors; the first radiates its own heat, the latter reflect the heat which they receive from other bodies.

CAROLINE.

Now, that I understand the difference, it no longer surprises me that bodies which radiate, or part with their own caloric freely, should not have the power of transmitting with equal facility that which they receive from other bodies.

EMILY.

Yet no body can be said to possess caloric of its own, if all caloric is originally derived from the sun.

MRS. B.

When I speak of a body radiating its own caloric, I mean that which it has absorbed and incorporated either immediately from the sun’s rays, or through the medium of any other substance.

CAROLINE.

It seems natural enough that the power of absorption should be in opposition to that of reflection, for the more caloric a body receives, the less it will reject.