"And God made a wind to pass over the earth."—Genesis viii.
665. Why is it difficult to strike limpets from rocks?
Because they have the means of forming a vacuum under their shells, and are pressed on to the rocks by the weight of the atmosphere.
666. Why can snails move over plants in an inverted position?
Because they form a vacuum with the smooth and moist surfaces of their bodies, and are supported by atmospheric pressure.