A. Because the sound of a bell (in the receiver of an air-pump) cannot be heard at all, after the air has been partially exhausted; and a pistol fired on a high mountain would not sound louder than a common cracker.
Q. Why do we feel braced and light-hearted on a fine spring or frosty morning?
A. 1st—Because there is more oxygen in the air on a fine frosty morning, than there is on a wet day: and
2ndly—A brisk and frosty air has a tendency to brace the nervous system.
Q. Why do dogs and cats (confined to a room) feel lazy and drowsy at the approach of rain?
A. 1st—Because the air does not contain its full proportion of oxygen: and
2ndly—Because the damp relaxes their nervous system, and makes them drowsy.
Q. Why do horses neigh, cattle low, sheep bleat, and asses bray, at the approach of rain?
A. 1st—As the air does not contain its full proportion of oxygen, they feel a difficulty in breathing: and