A. Because it is spread out, (like a piece of gold beaten into leaf); and as a square inch of gold leaf will not contain so much gold as a square inch of bullion—so, a square inch of rarefied air has less body, than a square inch of cold air.
Q. Why does a fire burn more fiercely in the open air?
A. 1st—Because the air out-of-doors is more dense, than the air in-doors: and
2ndly—Because air is more freely supplied to a fire out-of-doors.
Q. Why is the air out-of-doors more dense than that in-doors?
A. Because the circulation is more free; and as soon as any portion has been rarefied, it instantly escapes, and is supplied by colder currents.
Q. Why does not a fire burn so freely in a thaw, as in a frost?
A. During a thaw, the air is filled with vapour; and, both moves too slowly, and is too much diluted to nourish the fire.
Q. Why does a fire burn so fiercely in windy weather?