LESSON II.
A STROLL BY THE SEA.
The sea and the land are always at war. When you are at the seaside, with spade and bucket to make "castles" and "pies" of the sand, you can see and hear the battle.
A wave comes rolling smoothly on towards the shore. It reaches the land and can go no further, and then, with a roar and a crash and splash of sparkling foam, it breaks. It spreads into a sheet of foaming water, and, after rushing as far as it can up the beach, it seethes back as the next wave takes up the battle.
What a grinding and tearing, as wave after wave is hurled at the land! That is the battle-cry of the land and sea! Most of the pebbles and the sand on the beach have been won from the land in the great fight. We might call them the spoils of war. Once they formed part of the solid land, the rock or cliff. Now they are loose fragments spread for mile after mile round our coast.
Every wave takes them up and has fine fun with them. Pebbles and sand are picked up, swirled along, and thrown at the shore. They are sucked back as the wave is broken by the land. And then the following wave takes them, grinds them and scrubs them together. Thus they are jostled hither and thither, up and down the coast; and, as a result of the long, long fight, rocks and cliffs become pebbles, sand, or mud.
Now if you look at the pebbles on the shore you see that many of them are smooth and round. Some are as round as the "marbles" you play with. No wonder, for the mighty sea has scoured them with sand and rolled them for miles.
As you know, the sea is not always at the same height. It falls and rises. Twice in every day it ebbs and flows; we call this movement of the sea the tides. At low tide we can explore the very bed of the ocean. We can visit the homes of the living, breathing animals, which, at high tide, are hidden far under water. Between the high-water mark and low-water mark is our hunting-place. There we shall find the play-ground and feeding-ground of many a strange creature.
Here is a stretch of sand, with little channels of water; there is a patch of shingle mixed with numbers of tiny shells. The ebbing tide leaves shallow pools in every hollow of the beach, and these pools are often full of life.