was not so ominous, somehow, as the smaller voices of the ripples sucking and gurgling so close to their ears.
They walked along, three ghostly figures in the moonlight, until Janet, who happened to be ahead, stopped suddenly.
"I hear something strange; I don't understand what it is," she said.
Oliver stepped forward, bending his head to listen. Yes, he could hear it, too.
The sound was a soft hissing, as though a tiny snake might be hidden in the grass at their feet. But there was no grass thick enough for such shelter, only a few sparse stalks, rising in a drift of sand at the foot of the dike. The noise was made by the moving of the sand particles, as they stirred and seethed, with drops of water bubbling between them like the trickle of a spring. As they watched, the round wet space widened; it had been as big as a cup, now it was like a dinner plate.
"It's a leak in the bank." Oliver regarded it intently, thinking it quite too small to be dangerous. "I ought to be able to put my thumb in it," he added cheerfully, "but either there is something wrong with that Dutch story or there is something wrong with this hole."
"It isn't a joke," said Polly quickly. "They always begin that way. It—oh, run, run!"
For the boiling circle of sand had changed suddenly to a spout of muddy water that shot upward,
