Only a strong man can become or, at least, long remain a successful diver. No one is fit for the calling who suffers from headache, neuralgia, deafness, palpitation of the heart, intemperance, or a languid circulation. The pressure of the atmosphere increases the lower one descends, until a point is reached where life could not be maintained. The greatest depth, perhaps, ever reached, was 201 feet, with an atmosphere pressure of 87 pounds to the square inch. A diver named Green worked in 145 feet in Lake Ontario, but he was paralyzed, and never did a day's work afterward. Most divers do not care to work much deeper than 120 feet, and even for 30 or 40 feet, a moderate depth, considerable nerve and practice are requisite. The lower the depth, the more acute the pains felt in the ears and about the eyes, and symptoms of paralysis become more pronounced. An asthmatic man, on the other hand, may be cured by diving, the constant supply of fresh air, and the pressure which drives the blood so rapidly opening up the lungs. Divers as a rule cannot stand close rooms, being so accustomed to a copious supply of fresh air that they must have plenty of it, even when they are above water. In diving, the supply of air is increased according to the depth. At thirty feet below the surface fifteen pounds of air to the square inch is used, at sixty feet thirty pounds, and so on. Still, much depends on the man, and some divers work in eighty feet of water with only forty-five pounds. In the laying of masonry under the water and other work of the kind, the diving dress is usually replaced by the diving bell. This is a large vessel full of air, but open at the bottom, fresh air being pumped into it by air pumps. It is furnished with seats, and a chain passes through the center, by which weights can be raised or lowered. The diving bell has this advantage over the dress, that several men can work in company; on the other hand, should an accident happen, more lives are involved. Some years ago the chain of a diving bell in use at a pier in Dover, England, got fouled in some way and its occupants found themselves in a most alarming predicament. However, a diver named William Wharlow, donning his suit, descended, crowbar in hand, and after several hours of hard work, succeeded in freeing the chain, when the diving bell was hauled up in safety. It was stated a little while ago that some divers have an ineradicable dread of the dead; many will not have anything to do with them, when they come upon them by accident they will be unnerved and useless for the rest of the day, and those who make a virtue of necessity, when on a wreck generally insist upon getting the bodies out first. The temperature of the water always tells the diver where to look for bodies in a wreck; if it is cold they will be on the floor or lying in the berths; if warm they rise to the ceiling or against the bottom of the berth above.