PENETRATION

, the act by which one thing enters another, or takes up the place already possessed by another.

The schoolmen define Penetration the co-existence of two or more bodies, so that one is present, or has its extension in the same place as the other.

Most philosophers hold the penetration of bodies absurd, i. e. that two bodies should be at the same time in the same place; and accordingly impenetrability is laid down as one of the essential properties of matter.

What is popularly called Penetration, only amounts to the matter of one body's being admitted into the vacuity of another. Such is the Penetration of water through the substance of gold.