"For ordinary purposes there is a very simple arrangement, which consists of a box with a plate of glass in the bottom. You put this in the water, so that the glass is a few inches below the surface, and then you can see very clearly, where the depth is not too great. Fishermen in some parts of the world have something of the same nature, which they call a telescope; it is nothing but a tube of wood four or five feet long, and six inches in diameter, and with the top so arranged that when the eye is put against it there can be no entrance of light at that end of the tube. When a man wishes to examine the bottom of the sea where he is fishing, he sinks this tube and looks through it. He can make out many objects that are altogether invisible under ordinary circumstances, and can frequently discover the whereabouts of a school of fish that might otherwise escape him.
SUBMARINE OBSERVATIONS.
"Sometimes a man who is using one of these aids to marine observation finds himself the object of attentions he would gladly avoid. A friend of mine was once looking through a box from the side of a boat, when a large sawfish came from below and thrust his snout through the glass. A shark followed the sawfish, and was evidently anxious for a fight, and the two swum off together, to the satisfaction of my friend. What made the matter more exciting was that an expert swimmer had just dived from the boat, and gone down to take a survey of the coral-trees that grew on the bottom. He came up safe and undisturbed, and the probabilities are that the sawfish and shark had been too busy over each other and the glass-bottomed box to pay any attention to such an insignificant object as a man swimming near them.
THE BELLOWS-FISH, OR ANGLER.
"The bottom of the sea abounds in many curious things that we never see at the surface, unless they are brought there. There is a fish known as the Lophius, or bellows-fish; he is also called 'the angler,' from his artistic way of supplying himself with food. He seems to be nearly all mouth, and reminds you of the dog that could walk down his own throat without touching the sides. He has a long rod projecting from the middle of his forehead, and at the end of it there is a lump of flesh, like a morsel of beef. This rod is movable; and, as he lies flat on the mud, he spreads his great mouth open like a trap. Then he angles, or fishes, with his rod, moving it up and down and on both sides, so as to attract fish or crabs, or anything else that is edible. When they come within reach of his capacious jaws he closes on his prey, and goes on with his fishing as unconcerned as a man who has caught a small trout, and stowed it away in his basket."