Now, that no such Deluge as that described in Genesis ever took place is as certain as that the earth moves about the sun. Physical science tells us that it never _could_ have occurred; geology, zoology, ethnology, and history all tell us alike that it never _did_ occur. Physical science tells us two things about water: that it cannot be made out of nothing, and that it always finds its level. In order to cover the highest mountains on the earth and remain stationary at that level for months, we must suppose an uniform shell of water of six miles in depth to be added to the existing water of the earth. Even if we take Ararat as the highest mountain covered, the shell must have been three miles in thickness over the whole globe. Where did this water come from, and where did it go to? Rain is simply water raised from the seas by evaporation, and is returned to them by rivers. It does not add a single drop of water to that already existing on the earth and in its atmosphere. The heaviest rains do nothing but swell rivers and inundate the adjacent flat lands to a depth of a few feet, which rapidly subsides. The only escape from this law of nature is to suppose some sudden convulsion, such as a change in the position of the earth's axis of rotation, by which the existing waters of the earth were drained in some latitudes and heaped up in others. But any such local accumulation of water implies a sudden and violent rush to heap it up in forty days, and an equally violent rush to run it down to its old level when the disturbing cause ceased, as it must have done in 150 days. Such a disturbance in recent times is not only inconsistent with all known facts, but with the positive statement of the narrative that the whole earth was covered, and that the Ark floated quietly on the waters, drifting slowly northwards, until it grounded on Ararat. The only other alternative is to suppose a subsidence of the land below the level of the sea. But a subsidence which carried a whole continent 15,000, or even 1500 feet down, followed by an elevation which brought it back to the old level, both accomplished within the space of twelve months, is even more impossible than a cataclysmal deluge of water. Such movements are now, and have been throughout all the geological periods, excessively slow, and certainly not exceeding, at the very outside, a few feet in a century.