A diver?s helmet is really not a helmet in the ordinary acceptation of the term, but is a small air chamber firmly bolted to the corselet and incapable of movement from any volition on his part. He simply turns his head inside it and looks through either side or front glasses, exactly as a man looks through a window. A diver?s most real danger is probably the risk he runs of being drowned when on his way to the surface, and it occurs in this way. After a time the best of diving dresses becomes leaky to a more or less extent, and the water that finds its way through, settles about the feet and legs. Divers become quite accustomed to having their dresses filled with water up to the knees and even to the thigh; the water is no inconvenience to them whilst upright on the bottom, and they are very rarely conscious of it. Well, ????? suppose a diver has his dress full of water to the knees or thighs; as he ascends, he may involuntarily or by accident allow his body to assume a horizontal position, in which case the water at once rushes into the helmet, overbalances him, i.e. really stands him on his head, and drowns him inside his dress.

In a diving dress every beat of the air pump is perfectly audible to the diver, and any irregularity or alteration of the pace, at which the air-pump wheels are turned, is to him irritating in the extreme?an irritation he invariably works off by signalling for more air and thus increasing the manual labour at the pumps. It takes four men, straining hard, to keep a diver properly supplied with air at any depth over twenty fathoms. One of the greatest discomforts a diver has in the tropics is the smell of warm oil, more or less rancid, with which the pumps charge his air; I have had to struggle hard to prevent being sick, and I leave to the imagination the beastly situation of a man, with his head confined in a small helmet, overcome by nausea! Another exasperating thing is the scroop made by a grain of sand or grit getting into the plunger of the air pump, which is only comparable to the feeling caused by a drop of water falling upon one?s head at regular intervals.