A. The air nearest the fire is made hot first; the cold air descends, is heated also, and rises in turn; and this goes on, till all the air of the room is warmed.
Q. Why are fires placed on the floor of a room, and not towards the ceiling?
A. As heated air always ascends, if the fire were not near the floor, the lower part of the air (which we want to be the warmest) would never be benefited by the fire at all.
Q. If you take a poker out of the fire, and hold the hot end downwards, why is the handle so intensely hot?
A. Because the hot end of the poker heats the air around it, and this hot air (in its ascent) scorches the poker, and the hand which holds it.
Q. How should a red-hot poker be carried so as not to burn our fingers?
A. With the hot end upwards; because then the air (heated by the poker) would not pass over our hand to scorch it.
Q. Why is a poker (resting on the fender) cold; but if it leans against the stove, intensely warm?
A. The poker is an excellent conductor; while, therefore, it rests against the hot stove, the heat of the stove is conducted into the poker; but when it rests on the fender, it does not come in contact with the hot stove.