The Mud which Stopped Navigation.—We are told by Plato, "Atlantis disappeared beneath the sea, and then that sea became inaccessible, so that navigation on it ceased, on account of the quantity of mud which the ingulfed island left in its place." This is one of the points of Plato's story which provoked the incredulity and ridicule of the ancient, and even of the modern, world. We find in the Chaldean legend something of the same kind: Khasisatra says, "I looked at the sea attentively, observing, and the whole of humanity had returned to mud." In the "Popol Vuh" we are told that a "resinous thickness descended from heaven," even as in Dominica the rain was full of "thick gray mud," accompanied by an "overpowering smell of sulphur."
The explorations of the ship Challenger show that the whole of the submerged ridge of which Atlantis is a part is to this day thickly covered with volcanic débris.
We have but to remember the cities of Pompeii and Herculaneum, which were covered with such a mass of volcanic ashes from the eruption of A.D. 79 that for seventeen centuries they remained buried at a depth of from fifteen to thirty feet; a new population lived and labored above them; an aqueduct was constructed over their heads; and it was only when a farmer, in digging for a well, penetrated the roof of a house, that they were once more brought to the light of day and the knowledge of mankind.
We have seen that, in 1783, the volcanic eruption in Iceland covered the sea with pumice for a distance of one hundred and fifty miles, "and ships were considerably impeded in their course."
The eruption in the island of Sumbawa, in April, 1815, threw out such masses of ashes as to darken the air. "The floating cinders to the west of Sumatra formed, on the 12th of April, a mass two feet thick and several miles in extent, through which ships with difficulty forced their way."
It thus appears that the very statement of Plato which has
