428. Why does the greatest quantity of rain fall at the equator?
Because the hot air absorbs a large amount of vapour, and as the atmosphere is usually calm, there is an absence of currents, by which the saturated air would be removed. In this, which is called "the Region of Calms," rain falls almost daily.
429. Why are some parts of the earth rainless?
Because, being situated in tropical or torrid latitudes, and at a distance from the ocean, the atmosphere above them is always in a dry state.
"Thou, O God, didst send a plentiful rain, whereby thou didst confirm thine inheritance, when it was weary."—Psalm lxviii.
430. When is air said to be saturated with vapour?
When it cannot take up a larger quantity than that which it already holds.