water on it would sink down too, and leave the shore dry; till the sea-
bottom rose again, and hurled the water up again against the land. This
is one way of explaining it, and it may be true. For certain it is, that
earthquakes do move the bottom of the sea; and certain, too, that they
move the water of the sea also, and with tremendous force. For ships at
sea during an earthquake feel such a blow from it (though it does them no
harm) that the sailors often rush upon deck fancying that they have
struck upon a rock; and the force which could give a ship, floating in
water, such a blow as that, would be strong enough to hurl thousands of
tons of water up the beach, and on to the land.

But there is another way of accounting for this great sea wave, which I
fancy comes true sometimes.

Suppose you put an empty india-rubber ball into water, and then blow into
it through a pipe. Of course, you know, as the ball filled, the upper
side of it would rise out of the water. Now, suppose there were a party
of little ants moving about upon that ball, and fancying it a great
island, or perhaps the whole world--what would they think of the ball's
filling and growing bigger?

If they could see the sides of the basin or tub in which the ball was,
and were sure that they did not move, then they would soon judge by them
that they themselves were moving, and that the ball was rising out of the
water. But if the ants were so short-sighted that they could not see the
sides of the basin, they would be apt to make a mistake, because they
would then be like men on an island out of sight of any other land. Then
it would be impossible further to tell whether they were moving up, or
whether the water was moving down; whether their ball was rising out of
the water, or the water was sinking away from the ball. They would