The habits of fish are rather quaint. Should they be near the surface when a shadow falls on the water, a flick of the tail sends them disappearing into the depths. But undersea they are as inquisitive as cows. When fish see a diver standing still on the bottom, they find something about him too fascinating to withstand. Perhaps it is his form, perhaps the long line of bubbles flowing continually from the exhaust valve of his helmet. Whatever it is, they are drawn to the strange creature, and their fishy mouths suck at arms and legs and body in an effort to find out whether the diver is good to eat. The least movement sends them speeding away. The bigger fish are just as inquisitive, and just as easily scared. The diver needs only to open his air valve to let a little air escape in order to frighten them out of their fishy wits. Even the shark, the so-called tiger of the seas, is not generally feared by divers, for he is as scared by a sudden escape of air from the valve as are the smaller fish. Yet the shark is fearfully inquisitive, and will come back again and again to see what the strange figure is doing. Sometimes, indeed, the same shark becomes such a confounded nuisance, and the diver wastes so much time in scaring him away, that he is forced to put an end to the intrusion by slaying the monster. One diver, who had been worried day after day by the same shark, was compelled to signal to the surface for a knife. He then calmly held out his hand as bait, just as you hold out a bone to a dog, and as the monster turned to snap the delicacy, he stabbed it to death. Slipping a noose round the body of the fish, he sent it to the surface so that it would not attract other unwelcome visitors--for the scent of death in the sea is carried far afield by the invisible currents and soon brings the sea creatures swarming round--and was then able to resume his work in peace. As already mentioned, it is often difficult for divers to see owing to the sand and mud suspended in the water, especially near the mouths of big rivers. A few feet down, and the light is quite shut out by the clouds of mud and sand floating about. Sometimes the divers work up to their armpits in foul slime--I recollect some years ago when a racing yacht was recovered from underneath 20 feet of mud--at other times the mud is so deep and thick that they spread-eagle themselves on its surface and manage to work in this recumbent attitude.