A. Because the porous earth on the bank sups up water to the roots of the plants by capillary attraction.
Q. Why is a lump of sugar (left at the bottom of a cup) so long in melting?
A. Because as it melts, it makes the tea above it heavier; and (so long as it remains at the bottom) is surrounded by tea fully saturated with sugar; in consequence of which, the same portions of liquid will hold no more sugar in solution.
Q. Why does the lump of sugar melt more quickly when stirred about?
A. Because fresh portions of unsaturated tea keep coming in contact with the lump, and soon dissolve it.
Q. Why does a piece of sugar (held in a spoon at the top of our tea) melt very rapidly?
A. Because as the tea becomes sweetened, it descends to the bottom of the cup by its own gravity; and fresh portions of unsweetened tea are brought constantly into contact with the sugar, till the lump is entirely dissolved.
Q. How can a sick room be kept free from unhealthy effluvia?
A. Vinegar boiled with myrrh, or camphor, sprinkled in a sick room, will entirely correct putridity.