was much obliged to him and gave him a shilling-an English shilling of course, which is equal in value to nearly a quarter of a dollar. The porter made him a low bow, thanked him and went away.

Grimkie then called the waiter and paid for the refreshments he had ordered, which the waiter said came to one and six pence. He also gave the waiter a shilling for himself, and then he and John left the hotel and went back to the seat on the bench where Florence was waiting for them.

"Ah, Florence," said John, "you don't know what a nice luncheon we had of bread and cheese and milk."

"I wish I had gone too," said Florence.

"Ah, you could not go," said Grimkie. "Ladies never go to the coffee-rooms in England." "They do in France," said Florence.

"Yes," said Grimkie, "they do in France, everywhere."

"That is the reason why I like France better than England," said Florence.

CHAPTER V.

$

DEEP WATER.

In a former chapter I explained how it hap pened that generally along the coast of an island like England, the water is shallow, being made so in consequence of the filling up of the bed of the sea near the shore, by the deposit of sand and gravel produced by the disintegration of the cliffs that form in many places the margin of the land. I must now explain how it happens that in some places deep channels of water are produced, by means of which ships can come up near the land, or even within the land sometimes, where there are openings leading to bays or harbors within.

These deep channels are generally formed by the flowing in and out of the tides through · openings in the line of the coast, by means of which the sand is washed out and carried away, and a deep passage way for the water is kept open. Of course, in order to have this effect produced, it is necessary that the opening into the land should communicate with some expanse

within, which may serve as a reservoir for the water which is carried in by the tide. It is necessary, too, that this reservoir should be pretty large so as to receive and retain a considerable quantity of water when the tide is up, such as will produce a powerful rush when it flows out, so as to dig out the channel well and keep it clear.

Sometimes a river serves as such a reservoir. When the tide rises, off the mouth of the river, the water flows in, and if there is but little fall in the river, it flows up many miles. If now the tide rises ten or twelve feet, as it often does, and the river is half a mile wide and twenty or thirty miles long before, in ascending it, we come to a rise in the bed of the stream sufficient to arrest the progress of the water, then the tide will flow in until all that space is filled. Now it must take an enormous quantity of water to fill up a river half a mile wide and twenty miles long, to the depth of ten feet above its ordinary level; and all this vast amount has to pour in and out at the mouth of the river twice every day. It is easy to see that this strong current going back and forth with such a rush must wear out deep channels in the sands that line the coasts, and make passage ways for ships to come out and go in.

Sometimes, instead of a river, it is a sort of lake, or a bay, with a very narrow entrance opening from the sea, which forms, the reservoir to receive the tidal water that flows in and out. In this case, the tide when it rises pours in through the opening leading in from the sea, and continues to pour in until the whole surface of the lake or harbor is raised as high as the water outside. This, if the lake or harbor is large, and if the tide rises high, requires a vast amount of water. Then when the tide falls, all this water runs out, and carries out with it a great quantity of sand and gravel from the channel ways, and thus deepens them and keeps them clear, so that vessels can pass in and out in deep water.

Now if you look upon the map* you will see that the Isle of Wight is separated from the main land by a narrow channel, and on the north side of it, on the coast of England, there are two places where channels of deep water are formed, one by a sort of lake and the other by a river. The one where the deep channels are formed by a lake is Portsmouth, and the lake becomes what is called Portsmouth harbor. This lake thus performs a double function. It

* See map at the commencement of Chapter VII.