In those that are of a porous or spongy nature.
Why does a lump of sugar or salt, when partly dipped into water, soon become entirely wet?
Because sugar and salt are porous substances, and the water rises in them by capillary attraction.
Why does a heap of dry sand soon become damp when one edge touches the water?
Because the water is drawn through the sand by capillary attraction.
Why does water poured into the saucer of a flower-pot soon wet the earth in the flower-pot?
Because the earth is porous, and the water is drawn up through it by capillary attraction.
How does the oil in a lamp rise so as to be burned?
The oil is drawn up through the wick by capillary attraction.
Where may examples of capillary attraction be noticed?