"This ferry boat connects with a steamer on the canal, which goes to the Helder, and also with various trekschuyts. We shall take a trekschuyt to go for a short distance?—as far as to the place where we shall get a carriage."

"Very well," said Mr. George. "Arrange it as you think best. Then we shall go a short distance on the great canal."

"Yes, sir," said James. "You will like to see a little of the canal."

"I shall, indeed," said Mr. George.

The great canal of which James here spoke is the grandest work of the kind in Holland, and perhaps in the world. If you look at the map you will see that Amsterdam stands somewhat in the interior of the country, and that the only approach to it, by sea, is through a great gulf called the Zuyder Zee. Now, the water in the Zuyder Zee is shallow. There are channels, it is true, that are tolerably deep; but they are very winding and intricate, and they are so surrounded with shoals and sand banks as to make the navigation very difficult, especially for ships of large size.

The people, accordingly, conceived the plan of digging a canal across the country; from Amsterdam to the nearest place where there was deep water on the sea. This was at a point of land called the Helder.

The reason why there was deep water there, was, that that was the outlet for the Zuyder Zee, and the water rushing in there when the tide is rising, and out again when it goes down, keeps the channel deep and clear.

So it was determined to make a canal from the Helder to Amsterdam. But the land was lower, almost all the way, than the sea. This rendered it impossible to construct the canal so as to make it of the same level with the sea, without building up the banks of it to an inconvenient height. Besides, it was just as well to make the canal lower than the sea, and then to build gates at each end of it, to prevent the sea water from coming in.

"Then how were the ships to get in?" asked Rollo, when Mr. George explained this to him.

"Why, there were two ways," replied Mr. George, "by which ships might get in. You see, although the canal is lower than the sea is generally, there is an hour or two every day when the tide goes down, in which the two are about on a level. Accordingly, by opening the gates when the tide is low, a communication would be made by which the vessels could sail in and out."