DIVING, whether in shallow water or in the deep sea, is ever a fascinating occupation, and the latter probably more so than the former. Not only has diving an element of fascination, but it also has the merit of antiquity. In the “Iliad”, one of the world's oldest literary masterpieces, diving for oysters is mentioned, and Thucydides, the Greek historian, alludes in his writings to the work performed by the divers who, during the siege of Syracuse, sawed down the barriers that had been constructed below the surface of the water by the enemy with the object of wrecking any Greek war vessel attempting to force an entrance into the harbour. In ancient Rome divers were frequently employed to salvage sunken property, and in some cases they were allowed, as a kind of perquisite, a definite proportion of the value of the wreck salvaged, the amount paid varying according to the depth of the sunken vessel and the risks incurred during the salvage operations.
In many parts of the world the primitive method of diving is still in vogue, as, for example, in the Ceylon pearl fishing grounds, in the Mediterranean sponge fisheries, and in the Bahama waters.
Deep-sea diving is, as one would expect, exceedingly exhausting and trying work. Sometimes the strain on the diver is so severe that blood oozes from the nose, the ears, and the mouth, and when this happens the diver is not infrequently dragged back to the boat in an insensible condition. Slight men of muscular build, with good circulation, sound hearts, steady nerves, and temperate habits, make the best divers. "How long can a diver remain under water?" is a question often asked. Well, this, of course, depends on each individual diver, some divers being able to stand a greater strain on their system than others. So far as authentic records are available, the longest time that a diver has been known to remain below the surface of the water is three minutes.
Many different expedients for diving have been tried or adopted at various times; in fact, the history of deep-sea diving is intensely interesting. One method commonly employed in connection with pearl fishing and sponge fishing is for the diver's body to be well rubbed with oil, and the ears protected by the insertion of a plug of wool saturated with oil.
The number of times that the Ceylon pearl divers will descend into the water in a single day is not more than thirty or forty. The means taken to descend is to lay hold of a rope with one hand, and to insert a foot in a loop made in another rope to which a heavy stone is attached, with which the diver sinks to the bottom.
The idea of supplying the diver with air while he is under the water dates back to the sixteenth century. In an old book written during that period there is an engraving representing a diver wearing a light fitting helmet, to which is attached a long leather pipe leading to the surface of the water. By the use of a bladder the open end of the tube was kept above the level of the water. It is thought that this idea was suggested to the inventor by the action of the elephant in keeping its trunk above the water when it is crossing a river.