A. 1st—Because it beats down the noxious exhalations collected in the air, and dissolves them:
2ndly—It mixes the air of the upper regions with that of the lower regions: and
3rdly—It washes the earth, and sets in motion the stagnant sewers and ditches.
Q. Why are mountainous countries more rainy than flat ones?
A. The air (striking against the side of the mountains) is carried up the inclined plane, and brought in contact with the cold air of the higher regions, by which it is condensed, and its vapour squeezed out.
Q. Why does a sponge swell when it is wetted?
A. Because the water penetrates the pores of the sponge, and drives the particles of the sponge further from each other; in consequence of which, the bulk of the sponge is greatly increased.
Q. Why do fiddle-strings snap in wet weather?
A. Because the moisture of the air (penetrating the string) causes it to swell; and (as the cord thickens) its tension is increased, and the string snaps.