some of it. Thereby molecular motion is set up in the glass itself and it becomes warm, radiating heat in just the same manner as a stove radiates it.
The heat “absorbed” by a substance—that is, converted into molecular motion—in time may be stored until it is again radiated and is given out as warmth. It is conveniently called “sensible heat.” It is thus distinguished from the ether waves
Convectional movements of the air; sectional view.
that have great physical power, but do not directly impart the sense of warmth. One cannot draw a line between the sensible and the ultra-sensible heat waves, however; and the use of the term, though convenient, is not exact. Weather science deals chiefly with the sensible heat of the air.
Diffusion of Heat.—As a body becomes warm, the heat may diffuse itself through the mass rapidly, as in the case of metals,
