The earliest authentic records we have of the use of diving apparatus belong to the beginning of the sixteenth century. In an edition of Vegetius on the Art of War, published in 1511, there is an engraving of a diver walking in the sea with a cap over his head and shoulders, from which a flexible tube rises to the surface. This was, no doubt, the embryo of our “diving-dress.” John Taisner, in 1538, says that he saw two Greeks, at Toledo in Spain, make experiments with diving apparatus, in presence of the Emperor Charles the Fifth and ten thousand spectators. Gaspar Schott of Numberg, in 1664, refers to this Greek machine as an “aquatic kettle;” but mentions, as preferable in his estimation, a species of “aquatic armour,” which enabled those who wore it to walk under water. The “aquatic kettle” was doubtless the embryo of the diving-bell.
From that time onward inventive minds have been turned, with more or less success, towards the subject of submarine operations, and many are the contrivances—clever, queer, absurd, and useful—which have been the outcome. Not content with “kettles” and “bells,” by means of which they could descend into the deep and remain there for an hour or more at a time, and with “armour” and “dresses” with which they could walk about at the bottom of the sea, men have constructed several submarine boats and machines, in which, shut up like Jonah in the whale, they purposed to move about from place to place, sink to the bottom and rise to the surface, at will, or go under the bottoms of enemy’s ships and fix torpedoes wherewith to blow them up, and otherwise do them damage. These latter machines have not attained to any noteworthy degree of success—at least they have not yet done either much good or much harm to the human race; but the former—the “kettles” and the “armour,”—in other words, the “diving-bells” and “dresses”—have attained to a high degree of perfection and efficiency, and have done incalculable good service.
The diving-bell was so styled owing to the first machines being made in the shape of a gigantic bell. An inverted wine-glass, thrust mouth downwards into water, will not fill with water, owing to the air which it contains keeping the water out. It will partially fill, however, because air is compressible, and the deeper down it is thrust the more will the air be compressed. At a depth of thirty-three feet the air will be compressed to half its bulk—in other words, the glass will be half-full of water. It is clear that a fly or any small insect could live in the air thus confined although thrust to great depths under water. But it could not live long, because air becomes unfit for use after being breathed a certain time, and cannot sustain life. Hence, if we are to preserve the life of our fly, we must send fresh air down to it.
The first diving-bells were made so large that the air contained in them sufficed for a considerable period—an hour or more. When this air had lost its life-sustaining qualities, the bell had to be drawn up and the air renewed. This was so inconvenient that ingenious men soon hit on various plans to renew the air without raising the bells. One plan, that of Dr Halley, was to send air down in tight casks, which were emptied into the bell and then sent up, full of water, for a fresh supply of air, while the foul air was let out of the bell by a valve in the top. Another plan was to have tubes from the bell to the surface by which air was made to circulate downwards, at first being forced down by a pair of bellows, and afterwards by means of air-pumps.
Round the inside of the bell ran a seat for the divers. One or more holes fitted with thick plate-glass, gave them light and enabled them to use the various tools and implements required in their vocation. From some of these bells, a man could be sent out, when at or near the bottom, having on a water-tight head-piece connected by a tube with the air inside the bell. He could thus move about with more freedom than his comrades inside, but of course could not travel further than the length of his tube, while, being wet, he could not endure the cold for any great length of time.
As time went on the form of the bell was improved until that of a square or oblong box of iron came to be generally adopted. The bell now in use is that which was made in 1788 by the celebrated engineer Smeaton, who applied the air forcing-pump to it, and otherwise brought the machine to a high degree of perfection. He used it with great advantage in the works at Ramsgate harbour, and Smeaton’s diving-bell, improved by Rennie, has continued in constant and general use on all submarine works until a very recent period. It has now been almost entirely superseded—except in the case of some special kinds of work—by the diving-dress—the value and the use of which it is the province of our tale to illustrate and expound.
In regard to the diving-dress, we may say that it has grown out of the “aquatic armour” of the olden time, but no great advance in its improvement was made until the end of the eighteenth and beginning of the present centuries, when the names of Rowe, Halley, Spalding, Bushwell, and Colt, appear in connection with various clever contrivances to facilitate diving operations. Benjamin Martin, a London optician, made a dress of strong leather in 1778 which fitted his arms and legs as well as his trunk, and held half a hogshead of air. With this he could enter the hold of a sunk vessel, and he is said to have been very successful in the use of it. Mr Kleingert of Breslau, in 1798, designed a dress somewhat like the above, part of which, however, was made of tin-plate. The diving-dress was greatly improved by Mr Deane, and in the recovery of guns, etcetera, from the wreck of the Royal George, in 1834 to 1836, as well as in many other operations, this dress—much improved, and made by Mr Siebe, under Deane’s directions—did signal service.
It has now been brought to a high state of perfection by the well-known submarine engineers Siebe and Gorman, Heinke and Davis, and others, of London, and Denayrouze of Paris. It encases the diver completely from head to foot, is perfectly water-tight, and is made of thick sheet india-rubber covered on both sides with tanned twill—the helmet and breast-plate being metal.
For further information on this subject we refer the inquisitive reader to the Encyclopaedia Britannica, to the descriptive pamphlets of the submarine engineers above named, and to an admirable little book styled The Conquest of the Sea, by Henry Siebe, which contains a full and graphic account in detail of almost everything connected with diving and submarine engineering. (See Note 1.)