Plutarch's Platonic questions (7.8)

But the manner of the waters running over the earth is not so evident. But it is observable that the waters of lakes and ponds stand immovable, because the air about them stagnates immovable and admits of no vacuity. For the water on the surface of lakes and seas is troubled and fluctuates as the air is moved, it following the motion of the air, and moving as it is moved. For the force from below causes the hollowness of the wave, and from above the swelling thereof; until the air ambient and containing the water is still. Therefore the flux of such waters as follow the motion of the retreating air, and are impelled by that which presses behind, is continued without end. And this is the reason that the stream increases with the waters, and is slow where the water is weak, the air not giving way, and therefore suffering less reaction. So the

water of fountains must needs flow upwards, the extrinsic air succeeding into the vacuity and throwing the water out. In a close house, that keeps in the air and wind, the floor sprinkled with water causes an air or wind, because, as the sprinkled water falls, the air gives way. For it is so provided by Nature that air and water force one another and give way to one another; because there is no vacuity in which one can be settled without feeling the change and alteration in the other.