Well, Mrs. B., and what was the result?
MRS. B.
That we shall see; I have procured some ice for the purpose.
EMILY.
The thermometer falls considerably!
CAROLINE.
And does not that prove that cold is not merely a negative quality, implying simply an inferior degree of heat? The cold must be positive, since it is capable of reflection.
MRS. B.
So it at first appeared to Mr. Pictet; but upon a little consideration he found that it afforded only an additional proof of the reflection of heat: this I shall endeavour to explain to you.
According to Mr. Prevost’s theory, we suppose that all bodies whatever radiate caloric; the thermometer used in these experiments therefore emits calorific rays in the same manner as any other substance. When its temperature is in equilibrium with that of the surrounding bodies, it receives as much caloric as it parts with, and no change of temperature is produced. But when we introduce a body of a lower temperature, such as a piece of ice, which parts with less caloric than it receives, the consequence is, that its temperature is raised, whilst that of the surrounding bodies is proportionally lowered.