noble House of Normandy, which has played no inconsiderable part in the affairs of the United Kingdom.

It is hardly a century since the celebrated astronomer Halley, commencing the experiments in submarine exploration which have been continued to our time, descended to a depth of fifty feet in a diving-bell which he had constructed. His machine was made of wood, and covered with lead. The air that was vitiated by respiration escaped from the chamber through an aircock, and the pure element was supplied by barrels, which descended and ascended alternately on both sides of the bell, like buckets into a well. These barrels, lined with lead, each contained about thirty-six gallons of condensed air, and acted in some measure like two lateral lungs for the diving bell, with which they were connected by leather tubes. As soon as one of these air-casks was empty, they let down another. Halley himself relates that in 1721, by the aid of this engine, he was able to descend with four other persons to the depth of nine or ten fathoms, and to remain there an hour and a half.

The honour of having been the first to apply the diving-bell to the works of submarine architecture is due to Smeaton, the great engineer, whose name awakens so many echoes on the shores of Plymouth Sound. He it was who raised the far-famed Eddystone Lighthouse on a solitary rock fifteen miles out at sea. In 1779, Smeaton made use of the diving-bell to repair the piles of Hexham bridge, in the north of England, the foundations of the bridge having been undermined by the violence of the current. He also introduced various alterations in the form and appliances of the apparatus. About 1788, he was the first to construct a diving-bell of cast-iron; but the peculiar characteristic of his machine was the application of the air-pump.

This improved diving-bell was afterwards employed by all marine engineers. In 1813, it played an important part in the works which have so altered the port of Ramsgate. The celebrated Rennie, who directed this gigantic enterprise, made constant use of the diving-bell in fixing the foundations of the eastern jetty, and in protecting it in certain parts against the attacks of the sea by a shield of solid masonry. The same machine has also powerfully ⚫ contributed to developing the course of navigation between Glasgow and Greenock.

When

The diving-bell has many times rendered service to engineers by putting them in a position to understand the nature of certain damage going on, which too often threatens submarine works with complete destruction. Brunel was in the course of making his famous road under the Thames, and the current of the river had broken through the arched roof of the tunnel, he went down in a diving-bell to see for himself the extent of the disaster. The machine had sunk under the water to a depth of nearly thirty feet, and reached the gaping opening which had been hollowed out in the masonry. This hole was, however, too narrow to allow the bell to enter. It was, therefore, neces

sary, either to give up the pursuit of his observations, or have recourse to some other means for reaching the scene of operations, which was about eight or ten feet below him. Under these circumstances, there was no hesitation about Brunel; taking hold of the end of a rope, he plunged into the trench, and remained there, under water, for about two minutes. His companions began to be alarmed, and pulling the rope, gave him the signal to come up again. He, however, intently occupied in his important examination, had let go the rope, and had but just time to catch hold of it again at the very moment that this, his only means of safety, was being pulled away from him. On his return to the interior of the bell, he was much astonished at the time he had passed in the water.

Our engineers used the diving-bell until the year 1830; about this time another apparatus, more convenient and less costly, gradually took its place. The object of the diving apparatus is to give to each individual worker the utmost possible liberty of movement. An impervious habit, made of cloth and metal, allows him a certain liberty of motion, which he cannot possibly have when enclosed in a bell. A pipe communicating with the interior of his clothing supplies him with the air necessary for respiration. This apparatus is of French origin. Attempts of a different kind were made at the end of the last century by an inhabitant of Breslau. A diver, descended into the water carrying his supply of air in a reservoir, into which large quantities of this gas had been compressed. The man carried this reservoir on his back, and it communicated with his mouth by a tube. M. Hurr also made attempts to improve this apparatus in France, but without superseding the original invention. The discovery of caoutchouc about 1830 gave a great impulse to this industry, and to two Frenchmen, M. Rouquayrol, a mining engineer, and M. Denayrouze, a naval lieutenant, belong the honour of adapting an apparatus which suffices for all the exigencies of subaqueous work. Whether a man be naked or covered with impervious clothing, his respiration depends entirely on the exercise of his own will, and on the power of his lungs.

The reservoir, made of steel, is capable of resisting very great pressure, and is surmounted by a chamber so constructed as to regulate the afflux of air. The diver carries this apparatus on his back, a respiratory tube issues from this chamber, and is terminated by a mouth-piece composed of a piece of sheetcaoutchouc, which is held between the lips and the teeth of the diver, and this pipe is furnished with a valve, which permits the expulsion of the air, but opposes the entrance of water. It is obvious that the use of this apparatus renders the regular working of the air-pump unnecessary. An important advantage connected with this apparatus is that the expired air rises in bubbles to the surface. So long as the diver breathes regularly, the intervals which separate the appearance of the bubbles are sensibly equal. If they come more rapidly and more slowly than usual, it is a sign that something abnormal is

going on. If they cease altogether, the diver must have ceased breathing, and should be hauled up immediately.

The following is a remarkable example of a salvage effected by the help of this apparatus: "The packet boats' Ganges' and 'l'Impératrice' came into collision in the outer port of Marseilles. The 'Impératrice' had one of her wheels broken, and the officers' quarters damaged. One of the cabins contained a chest full of gold, which fell into the thick mud which forms the bottom of the port of Marseilles. It was important that this precious package should be recovered the next day. The sea was rough, and the exact spot where the accident occurred unknown. The box was not strong, its colour was black. At the supposed spot a plumb of 60 kilogrammes was sunk. This plumb carried two cords divided into metres; two divers dragged them in separate directions, and, taking each the knot corresponding to one metre, they described consecutive circles, examining the ground at each step. After searching three hours, the gold was found and restored to its owner, who had watched the operations with intense anxiety. This salvage was effected or February 19th, 1867, by M. Barbotin, contractor for submarine work at Marseilles.

The diving-bell proper has been much improved by M. Payerne. His "Submarine Hydrostat" possesses the immense advantage of being capable, at the will of those enclosed in it, either of floating on the surface, or of sinking or rising, as may be desired. Thirty men may work in it with ease for a number of hours without inconvenience. It is, therefore, of great service in clearing ports, and in facilitating the execution of other submarine work.

The principle of the machine is very ingenious. Externally, it has the appearance of one large rectangular box, surmounted by another smaller one, completely closed in except at the bottom. The interior consists of three principal compartments. The hold communicates by a large shaft with the upper compartment. Between these is a third compartment, or orlop deck, which only communicates with the others by means of stopcocks. The hydrostat is 20 feet in height, and its base, which has the bottom of the sea for a floor, covers an area of 625 square feet. It may be made to rise and fall at will, and it will readily float about like a raft. This ingenious machine has already been put to the test. The port of Fécamp was choked up with shingle, which closed it against all vessels beyond a certain tonnage. The hydrostat was employed, and the port cleaned and again opened to commerce. The cases in which it might be employed with advantage are obviously very

numerous.

Our tale of ingenuity is not yet finished. M. Villeroy, a French engineer, constructed at Philadelphia, a few years ago, a remarkable machine, intended to swim at any depth beneath the surface of the sea that its conductor might desire. This submarine vessel was shaped like a cylinder, with conical ends.

It was closed hermetically. It was lighted by a large number of circular windows cut in its iron skin, and closed up with thick glass. A hatchway allowed ingress and egress. Gutta-percha tubes, placed in the interior, communicated with the exterior by means of a conduit-tube furnished with a stopcock. By means of a pump the vessel could be filled with water at will. To cause the vessel to sink it was only necessary to allow the water to penetrate these tubes, its ejection caused the vessel to rise. A screw worked at the stern.

Villeroy's structure was 35 feet in length, and 44 inches in diameter. By lighting the bottom of the sea by means of an electric light placed in the interior of the vessel, a convenient method of exploration would be obtained, at least in the neighbourhood of the coasts.

We are glad to see that Messrs. Denayrouze & Co. are engaged by our Government in assisting to raise the wreck and materials of H.M.S. 'Vanguard,' which sunk in collision with her sister ironclad, the Iron Duke,' off the coast of Wicklow, Ireland, and we shall watch with interest the result of their experiments.

THE DOUGLAS PATENT BOAT-LOWERING APPARATUS. AMONG the many inventions for detaching boats at sea, the apparatus designed and patented by Mr. W. R. Douglas, a Scottish engineer, deserves more than a passing notice. Its greatest recommendation is its simplicity, which is an element of the highest importance when an emergency arises; for although the

old practice of lowering from the davits-always a difficult operation in a seaway-was simple enough, it entirely depended upon manual appliances, such as unhooking by hand, or relieving a kink in the fall.

Mr. Douglas's invention is exceedingly simple. Two cast-iron sockets are

fixed in the boat one in the bow, the other in the

estern Each of the davit blocks has an iron ball attached to its lower end, and these balls slip into the sockets and are kept there by two levers, so that the boat swings from the davits as if hooked on in the usual manner. When it is wished to lower the boat, the falls are eased off in the usual way till she is within two or three feet of the water. A trigger, to which the two levers are attached, is then let go by hand, the balls are freed, and the boat drops into the into the water on an even keel, entirely clear of the ship. In the old system the tackles could not be unhooked till the boat was in the water, and very often one of the tackles would be cleared before the other, the result being that one end of the boat being free dropped into the water while the other was held fast, thereby involving the swamping of the boat and risk of life.

We witnessed a series of experiments made with a model of the apparatus at the Sailors' Home, Glasgow, to which a number of nautical and scientific men were invited, and the result appeared to give unqualified approval. Several experiments were made at Leith, where the apparatus was fitted up on board the 'Lord Aberdour,' and successfully tested while the steamer was going at full speed. Experiments had previously been tried in Australia and New Zealand with complete success.

We need but refer to the recent melancholy wreck of the Schiller' on the Scilly Isles. It was reported at the time that two of her boats just at the critical moment got unhooked at one end only, with the usual result, namely the capsizing of the occupants into the sea.

We understand that a number of vessels have been fitted up with this apparatus, which is so simple that it can be understood by the commonest intellect.

C. K. M.'A.

MISCELLANEOUS.

"LAYS AND RHYMES FOR HOURS AT SEA." By E. J. Kelly.-We understand that Mr. Wells Gardner will shortly. publish this manual by the indefatigable lady collector of the Shipwrecked Mariners' Society at Clevedon.

THE BOYTON LIFE-DRESS.-Captain Boyton has proved himself a worthy disciple of Britannia, which rules the seas. He has learnt to ride on the billows, and, if he cannot as yet direct the storm, he can defy it. The man's pluck is immense, his perseverance is beyond all praise. To launch out into

a stormy sea equipped as he was, to be for twenty-three hours battling with winds and waves, is no small piece of heroism. He has accomplished his feat, by crossing the Channel and shown what can be done. How far the achievement will have a practical result yet remains to be seen. Manifestly it is not all nor many seafarers who could afford to purchase an apparatus so expensive as Captain Boyton's. Then, too, it is clear that though in some in stances life might be saved, in a good many the dress would merely prolong the agony of death. Probably the cost