They would probably say, "The water is sinking and leaving the ball dry." Do you understand that?
Then think what would happen if you pricked a hole in the ball.

The air inside would come hissing out, and the ball would sink again into the water.

But the ants would probably fancy the very opposite.

Their little heads would be full of the notion that the ball was solid and could not move, just as our heads are full of the notion that the earth is solid and cannot move; and they would say, "Ah! here is the water rising again." Just so, I believe, when the sea seems to ebb away during the earthquake, the land is really being raised out of the sea, hundreds of miles of coast, perhaps, or a whole island, at once, by the force of the steam and gas imprisoned under the ground.

That steam stretches and strains the solid rocks below, till they can bear no more, and snap, and crack, with frightful roar and clang; then out of holes and chasms in the ground rush steam, gases--often foul and poisonous ones--hot water, mud, flame, strange stones--all signs that the great boiler down below has burst at last.
Then the strain is eased.