Notwithstanding their varied tints, the fundamental colour of all seaweeds is green, as you can prove for yourselves by boiling a few brown specimens, or soaking them for some time in fresh water. You will find that the other colouring matters are dissolved out, and only the green is left. The red or brown pigments are probably of use in aiding or in protecting the green colouring matter, chlorophyll, in its important work of assimilating the food material. [Illustration] CRABS. When I was a boy at school we frequently amused ourselves by catching crabs. The scene of our operations was the Peerie Sea, where a wall had been built along the shore. Here we used to gather, armed with a piece of string and bait of some kind, and we often spent a whole long evening perched on the wall, fishing for crabs. The Peerie Sea was a receptacle for all kinds of refuse, and formed a happy hunting-ground for swarms of crabs. When one thinks of catching crabs, one may naturally imagine an excursion to the shore during ebb-tide, and much turning over of stones and seaweed. Our method was quite different. We made the crabs come to us. Our bait was a piece of fish or anything of an animal nature, provided it was fairly tough. No hook was necessary; we simply tied the end of the string round the bait. The baited line was let down into the water, preferably in the vicinity of a crab, and drawn slowly along the bottom. If the animal was timid, and not very hungry, he often scuttled off in a fright. Usually, however, he was both hungry and fearless, and seized the bait at once, trying to drag it in among seaweed or into a hole. Now came the exciting part of the business. Our object was to haul him up before he quitted his hold. The wall was high, and he required careful management. Sometimes when he was drawn up out of the water he would let go, and fall back with a flop into the sea again; sometimes he would hold on till he was drawn up over the wall, and then we shook him off on the pavement behind. [Illustration: _Common shore crab._] Occasionally when we had no bait we would manage to land a crab with a small stone or a cinder. So long as the stone lies motionless on the bottom he pays no attention to it. As soon as it begins to move, drawn along by the string, the crab rushes at it and seizes it with his claws, and it is some time before he finds out his mistake. Not infrequently he will allow himself to be drawn quite out of the water, clinging to his find. It is very amusing to see the crab worrying a hard stone, then dropping it when he has discovered it is not eatable, and then seizing it again as it begins to move away from him, just like a kitten with a ball of wool. Apparently he cannot resist the idea that movement means life.