All this time the knitting needles clicked on, and the pipe never missed a puff.

When the boys were fairly on their way again, they came in sight of the Zwanenburg Castle with its massive stone front, and its gateway towers, each surmounted with a sculptured swan.

"Halfweg, *{Halfway.} boys," said Peter, "off with your skates."

"You see," explained Lambert to his companions, "the Y and the Haarlem Lake meeting here make it rather troublesome. The river is five feet higher than the land, so we must have everything strong in the way of dikes and sluice gates, or there would be wet work at once. The sluice arrangements are supposed to be something extra. We will walk over them and you shall see enough to make you open your eyes. The spring water of the lake, they say, has the most wonderful bleaching powers of any in the world; all the great Haarlem bleacheries use it. I can't say much upon that subject, but I can tell you ONE thing from personal experience."

"What is that?"

"Why, the lake is full of the biggest eels you ever saw. I've caught them here, often--perfectly prodigious! I tell you they're sometimes a match for a fellow; they'd almost wriggle your arm from the socket if you were not on your guard. But you're not interested in eels, I perceive. The castle's a big affair, isn't it?"