The Brennan is used by our naval authorities. It is the invention of a Melbourne watchmaker. Being a comparatively poor man, Mr. Brennan applied to the Colonial Government for grants to aid him in the manufacture and development of his torpedo, and he was supplied with sufficient money to perfect it. In 1881 he was requested by our Admiralty to bring his invention to England, where it was experimented upon, and p.r.o.nounced so efficient for harbour and creek defence that at the advice of the Royal Engineers Mr. Brennan was paid large sums for his patents and services.

The Brennan torpedo derives its motive power from a very powerful engine on sh.o.r.e, capable of developing 100 horse-power, with which it is connected by stout piano wires. One end of these wires is wound on two reels inside the torpedo, each working a screw; the other end is attached to two winding drums driven at high velocity by the engine on sh.o.r.e. As the drums wind in the wire the reels in the torpedo revolve; consequently, the harder the torpedo is pulled back the faster it moves forward, liked a trained trotting mare. The steering of the torpedo is effected by alterations in the relative speeds of the drums, and consequently of the screws. The drums run loose on the engine axle, and are thrown in or out of gear by means of a friction-brake, so that their speed can be regulated without altering the pace of the engines. Any increase in the speed of one drum causes a corresponding decrease in the speed of the other. The torpedo can be steered easily to right or left within an arc of forty degrees on each side of straight ahead; but when once launched it cannot be retrieved except by means of a boat. Its path is marked by a Holmes light, described above. It has a 200-lb. gun-cotton charge, and is fitted with an apparatus for maintaining a proper depth very similar to that used in the Whitehead torpedo.

The Sims-Edison torpedo differs from the Brennan in its greater obedience to orders and in its motive power being electrically transmitted through a single connecting cable. It is over thirty feet in length and two feet in diameter. Attached to the torpedo proper by rods is a large copper float, furnished with b.a.l.l.s to show the operator the path of the torpedo. The torpedo itself is in four parts: the explosive head; the magazine of electric cables, which is paid out as the torpedo travels; the motor room; and the compartment containing the steering-gear. The projectile has a high speed and long range--over four thousand yards. It can twist and turn in any direction, and, if need be, be called to heel. Like the Brennan, it has the disadvantage of a long trailing wire, which could easily become entangled; and it might be put out of action by any damage inflicted on its float by the enemy's guns. But it is likely to prove a very effective harbour-guard if brought to the test.

In pa.s.sing to the Orling-Armstrong torpedo we enter the latest phase of torpedo construction. Seeing the disadvantages arising from wires, electricians have sought a means of controlling torpedoes without any tangible connection. Wireless telegraphy showed that such a means was not beyond the bounds of possibility. Mr. Axel Orling, a Swede, working in concert with Mr. J. T. Armstrong, has lately proved that a torpedo can be steered by waves of energy transmitted along rays of light, or perhaps it would be more correct to say along shafts of a form of X-rays.

Mr. Orling claims for his torpedo that it is capable of a speed of twenty-two knots or more an hour; that it can be called to heel, and steered to right or left at will; that as long as it is in sight it is controllable by rays invisible to the enemy; that not merely one, but a number of torpedoes can be directed by the same beams of light; that, as it is submerged, it would, even if detected, be a bad mark for the enemy's guns.

The torpedo carries a shaft which projects above the water, and bears on its upper end a white disc to receive the rays and transmit them to internal motors to be trans.m.u.ted into driving power. The rod also carries at night an electric light, shaded on the enemy's side, but rendering the whereabouts of the torpedo very visible to the steerer.

Mr. Orling's torpedo acts throughout in a cruelly calculating manner.

Before its attack a ship would derive small advantage from a crinoline of steel netting; for the large torpedo conceals in its head a smaller torpedo, which, as soon as the netting is struck, darts out and blasts an opening through which its longer brother, after a momentary delay, can easily follow. The netting penetrated, the torpedo has yet to strike twice before exploding. On the first impact, a pin, projecting from the nose, is driven in to reverse the engines, and at the same time a certain nut commences to travel along a screw. The nut having worked its way to the end of the thread, the head of the torpedo fills slowly through a valve, giving it a downward slant in front. The engines are again reversed and the nut again travels, this time bringing the head of the torpedo up, so as to strike the vessel at a very effective angle from below.

This torpedo has pa.s.sed beyond the experimental stage. It is reported that by command of the Swedish Government, to whom Mr. Orling offered his invention, and of the King, who takes a keen interest in the ideas of his young countryman, a number of experiments were some time ago carried out in the Swedish rivers. Torpedoes were sent 2-1/2 miles, directed as desired, and made to rise or sink--all this without any tangible connection. The Government was sufficiently satisfied with the result to take up the patents, as furnishing a cheap means of defending their coasts.

Mr. Orling has described what he imagines would happen in case of an attack on a position protected by his ingenious creations. "Suppose that I had twelve torpedoes hidden away under ten feet of water in a convenient little cove, and that I was directed to annihilate a hostile fleet just appearing above the horizon. Before me, on a little table perhaps, I should have my apparatus; twelve b.u.t.tons would be under my fingers. Against each b.u.t.ton there would be a description of the torpedo to which it was connected; it would tell me its power of destruction, and the power of its machinery, and for what distance it would go. On each b.u.t.ton, also, would be indicated the time that I must press it to release the torpedoes. Well now, I perceive a large vessel in the van of the approaching fleet. I put my fingers on the b.u.t.ton which is connected with my largest and most formidable weapon.

I press the b.u.t.ton--perhaps for twelve seconds. The torpedo is pushed forward from its fastenings by a special spring, a small pin is extracted from it, and immediately the motive machinery is set in motion, and underneath the water goes my little agent of destruction, and there is nothing to tell the ship of its doom. I place my hand on another b.u.t.ton, and according to the time I press it I steer the torpedo; the rudder answers to the rays, and the rays answer to the will of my mind."[2]

[2] _Pearson's Magazine._

If this torpedo acts fully up to its author's expectations, naval warfare, at least as at present conducted, will be impossible. There appears to be no reason why this torpedo should not be worked from shipboard; and we cannot imagine that hostile ships possessing such truly infernal machines would care to approach within miles of one another, especially if the submarine be reinforced by the aerial torpedo, different patterns of which are in course of construction by Mr. Orling and Major Unge, a brother Swede. The Orling type will be worked by the new rays, strong enough to project it through s.p.a.ce.

Major Unge's will depend for its motive power upon a succession of impulses obtained by the ignition of a slow-burning gas, pa.s.sing through a turbine in the rear of the torpedo. The inventor hopes for a range of at least six miles.

What defence would be possible against such missiles? Liable to be shattered from below, or shivered from above, the warship will be placed at an ever-increasing disadvantage. Its size will only render it an easier mark; its strength, bought at the expense of weight, will be but the means of insuring a quicker descent to the sea's bottom. Is it not probable that sea-fights will become more and more matters of a few terrible, quickly-delivered blows? Human inventions will hold the balance more and more evenly between nations of unequal size, first on sea, then on land, until at last, as we may hope, even the hottest heads and bravest hearts will shrink from courting what will be less war than sheer annihilation, and war, man's worst enemy, will be itself annihilated.

SUBMARINE BOATS.

The introduction of torpedoes for use against an enemy's ships below the waterline has led by natural stages to the evolution of a vessel which may approach unsuspected close enough to the object of attack to discharge its missile effectively. Before the searchlight was adopted a night surprise gave due concealment to small craft; but now that the gloom of midnight can be in an instant flooded with the brilliance of day a more subtle mode of attack becomes necessary.

Hence the genesis of the submarine or submersible boat, so constructed as to disappear beneath the sea at a safe distance from the doomed ship, and when its torpedo has been sped to retrace its invisible course until outside the radius of destruction.

To this end many so-called submarine boats have been invented and experimented with during recent years. The idea is an ancient one revived, as indeed are the large proportion of our boasted modern discoveries.

Aristotle describes a vessel of this kind (a diving-bell rather than a boat, however), used in the siege of Tyre more than two thousand years ago; and also refers to the divers being provided with an air-tube, "like the trunk of an elephant," by means of which they drew a fresh supply of air from above the surface--a contrivance adopted in more than one of our modern submarines. Alexander the Great is said to have employed divers in warfare; Pliny speaks of an ingenious diving apparatus, and Bacon refers to air-tubes used by divers. We even find traces of weapons of offence being employed. Calluvius is credited with the invention of a submarine gun for projecting Greek fire.

The Bishop of Upsala in the sixteenth century gives a somewhat elaborate description of certain leather skiffs or boats used to scuttle ships by attacking them from beneath, two of which he claims to have personally examined. In 1629 we read that the Barbary corsairs fixed submarine torpedoes to the enemy's keel by means of divers.

As early as 1579 an English gunner named William Bourne patented a submarine boat of his own invention fitted with leather joints, so contrived as to be made smaller or larger by the action of screws, ballasted with water, and having an air-pipe as mast. The Campbell-Ash submarine tried in 1885 was on much the same principle.

Cornelius van Drebbel, an ingenious Dutchman who settled in England before 1600, produced certain submersible vessels and obtained for them the patronage of two kings. He claims to have discovered a means of re-oxygenating the foul air and so enabling his craft to remain a long time below water; whether this was done by chemical treatment, compressed air, or by surface tubes no record remains. Drebbel's success was such that he was allowed to experiment in the Thames, and James I. accompanied him on one of his sub-aquatic journeys. In 1626 Charles I. gave him an order to make "boates to go under water," as well as "water mines, water petards," &c., presumably for the campaign against France, but we do not hear of these weapons of destruction being actually used upon this occasion.

[Ill.u.s.tration: _The "Holland" Submarine Boat._]

These early craft seem to have been generally moved by oars working in air-tight leather sockets; but one constructed at Rotterdam about 1654 was furnished with a paddle-wheel.

Coming now nearer to our own times, we find that an American called Bushnell had a like inspiration in 1773, when he invented his famous "Turtles," small, upright boats in which one man could sit, submerge himself by means of leather bottles with the mouths projecting outside, propel himself with a small set of oars and steer with an elementary rudder. An unsuccessful attempt was made to blow up the English fleet with one of these "Turtles" carrying a torpedo, but the current proved too strong, and the missile exploded at a harmless distance, the operator being finally rescued from an unpremeditated sea-trip! Bushnell was the author of the removable safety-keel now uniformly adopted.

Soon afterwards another New Englander took up the running, Fulton--one of the cleverest and least appreciated engineers of the early years of the nineteenth century. His _Nautilus_, built in the French dockyards, was in many respects the pattern for our own modern submarines. The cigar-shaped copper hull, supported by iron ribs, was twenty-four feet four inches long, with a greatest diameter of seven feet. Propulsion came from a wheel, rotated by a hand winch, in the centre of the stern; forward was a small conning-tower, and the boat was steered by a rudder. There was a detachable keel below; and fitted into groves on the top were a collapsible mast and sail for use on the surface of the water. An anchor was also carried externally. In spite of the imperfect materials at his disposal Fulton had much success. At Brest he took a crew of three men twenty-five feet down, and on another day blew up an old hulk. In the Seine two men went down for twenty minutes and steered back to their starting-point under water.

He also put in air at high pressure and remained submerged for hours.

But France, England, and his own country in turn rejected his invention; and, completely discouraged, he bent his energies to designing boat engines instead.

In 1821 Captain Johnson, also an American, made a submersible vessel 100 feet long, designed to fetch Napoleon from St. Helena, travelling for the most part upon the surface. This expedition never came off.

Two later inventions, by Castera and Payerne, in 1827 and 1846 respectively, were intended for more peaceful objects. Being furnished with diving-chambers, the occupants could retrieve things from the bottom of the sea; Castera providing his boat with an air-tube to the surface.

Bauer, another inventor, lived for some years in England under the patronage of Prince Albert, who supplied him with funds for his experiments. With Brunel's help he built a vessel which was indiscreetly modified by the naval authorities, and finally sank and drowned its crew. Going then to Russia he constructed sundry submarines for the navy; but was in the end thrown over, and, like Fulton, had to turn himself to other employment.

The fact is that up to this period the cry for a practical submarine to use in warfare had not yet arisen, or these inventions would have met with a far different reception. Within the last half century all has changed. America and France now rival each other in construction, while the other nations of Europe look on with intelligent interest, and in turn make their contributions towards solving the problem of under-wave propulsion.

America led the way during the Civil War blockades in 1864, when the _Housatonic_ was sunk in Charleston harbour, and damage done to other ships. But these experimental torpedo-boats were clumsy contrivances compared with their modern successors, for they could only carry their destructive weapon at the end of a spar projecting from the bows--to be exploded upon contact with the obstacle, and probably involve the aggressor in a common ruin. So nothing more was done till the perfecting of the Whitehead torpedo (see Dirigible Torpedoes) gave the required impetus to fresh enterprise.

France, experimenting in the same direction, produced in 1889 Goubet's submarine, patent of a private inventor, who has also been patronised by other navies. These are very small boats, the first, 16-1/2 feet long, carrying a crew of two or three men. _Goubet No. 2_, built in 1899, is 26-1/4 feet long, composed of several layers of gun-metal united by strong screw-bolts, and so able to resist very great pressure. They are egg-or spindle-shaped, supplied with compressed air, able to sink and rise by rearrangement of water-ballast.

Reservoirs in the hull are gradually filled for submersion with water, which is easily expelled when it is desired to rise again. If this system goes wrong a false keel of thirty-six hundredweight can be detached and the boat springs up to the surface. The propulsive force is electricity, which works the driving-screw at the rear, and the automobile torpedo is discharged from its tube by compressed air.

"By the aid of an optical tube, which a pneumatic telescopic apparatus enables the operator to thrust above the surface and pull down in a moment, the captain of the _Goubet_ can, when near the surface, see what is going on all round him. This telescope has a system of prisms and lenses which cause the image of the sea-surface to be deflected down to the eye of the observer below.

"Fresh air for the crew is provided by reservoirs of oxygen, and acc.u.mulations of foul air can be expelled by means of a small pump.

Enough fresh air can be compressed into the reservoirs to last the crew for a week or more."

The _Gymnote_, laid down in 1898, is more than double the size of the _Goubet_; it is cigar-shaped, 29 feet long by 6 feet diameter, with a displacement of thirty tons. The motive power is also electricity stored in acc.u.mulators for use during submersion, and the speed expected--but not realised--was to be ten knots.

Five years later this type was improved upon in the _Gustave Zede_, the largest submarine ever yet designed. This boat, built of phosphor-bronze, with a single screw, measures 131 feet in length and has a displacement of 266 tons; she can contain a crew of nine officers and men, carries three torpedoes--though with one torpedo tube instead of two--has a lightly armoured conning-tower, and is said to give a surface speed of thirteen knots and to make eight knots when submerged. At a trial of her powers made in the presence of M.

Lockroy, Minister of Marine, she affixed an unloaded torpedo to the battleship _Magenta_ and got away un.o.bserved. The whole performance of the boat on that occasion was declared to be most successful. But its cost proved excessive considering the small radius of action obtainable, and a smaller vessel of the same type, the _Morse_ (118 9 feet), is now the official size for that particular cla.s.s.

In 1896 a compet.i.tion was held and won by the submersible _Narval_ of M. Laubeuf, a craft shaped much like the ordinary torpedo-boat. On the surface or awash the _Narval_ works by means of a Brule engine burning oil fuel to heat its boilers; but when submerged for attack with funnel shut down is driven by electric acc.u.mulators. She displaces 100 odd tons and is provided with four Dzewiecki torpedo tubes. Her radius of action, steaming awash, is calculated at some 250 miles, or seventy miles when proceeding under water at five knots an hour. This is the parent of another cla.s.s of boats designed for offensive tactics, while the _Morse_ type is adapted chiefly for coast and harbour defence. The French navy includes altogether thirty submarine craft, though several of these are only projected at present, and none have yet been put to the practical tests of actual warfare--the torpedoes used in experimenting being, of course, blank.

Meanwhile in America experiments have also been proceeding since 1887, when Mr. Holland of New York produced the vessel that bears his name.

This, considerably modified, has now been adopted as model by our Navy Department, which is building some half-dozen on very similar lines.

Though it is not easy to get any definite particulars concerning French submarines Americans are less reticent, and we have graphic accounts of the _Holland_ and her offspring from those who have visited her.

These vessels, though cigar-shaped liked most others, in some respects resemble the _Narval_, being intended for long runs on the surface, when they burn oil in a four-cylinder gasolene engine of 160 horse-power. Under water they are propelled by an electric waterproof motor of seventy horse-power, and proceed at a pace of seven knots per hour. There is a superstructure for deck, with a funnel for the engine and a small conning-tower protected by 4-inch armour. The armament carried comprises five 18-inch Whitehead torpedoes, 11 feet 8 inches long. One hundred and twenty tons is the displacement, including tank capacity for 850 gallons of gasolene; the full length is 63 feet 4 inches, with a beam of 11 feet 9 inches.

[Ill.u.s.tration: _An interior view of the "Holland." The large pendulum on the right actuates mechanism to keep the Submarine at the required depth below the surface._]

The original Holland boat is thus described by an adventurous correspondent who took a trip in her[3]: "The _Holland_ is fifty-three feet long, and in its widest part it is 10-1/4 feet in diameter. It has a displacement of seventy-four tons, and what is called a reserve buoyancy of 2-1/2 tons which tends to make it come to the surface.

[3] _Pearson's Magazine._

"The frames of the boat are exact circles of steel. They are set a little more than a foot apart. They diminish gradually in diameter from the centre of the boat to the bow and stern. On the top of the boat a flat superstructure is built to afford a walking platform, and under this are s.p.a.ces for exhaust pipes and for the external outfit of the boat, such as ropes and a small anchor. The steel plates which cover the frame are from one-half to three-eighths of an inch in thickness.

"From what may be called the centre of the boat a turret extends upwards through the superstructure for about eighteen inches. It is two feet in diameter, and is the only means of entrance to the boat.

It is the place from which the boat is operated. At the stern is an ordinary three-bladed propeller and an ordinary rudder, and in addition there are two horizontal rudders--"diving-rudders" they are called--which look like the feet of a duck spread out behind as it swims along the water.