The Romance of Industry and Invention Part 9

This firm are now the leading warship builders in the world. Krupp's works at Essen (described in the earlier part of this book) are the only parallel to them in Europe. The engineering works, begun, as we have seen, in 1847, now occupy about nine acres; the ordnance works, founded ten years later, occupy about forty acres; while about five thousand men are employed. The shipbuilding yards are at Low Walker, nearer the sea.

The hydraulic machinery for the Tower Bridge and the Manchester Ship Ca.n.a.l were both produced by this great firm.

Some years ago one of his biographers wrote: 'He entertains the great inst.i.tutes of England when they visit his native city on royal lines, in regal splendour. His works at Elswick enjoy all modern improvements. His home at Jesmond is the abode of art, literature, and luxury. When his health complained under its heavy load, he cultivated agriculture, botany, and forestry for recreation; bought an estate at Rothbury, where the kindly invigorating air had healed him in days gone by; converted the barren hills into an earthly paradise; lighted his Cragside mansion with Swan's lamp and his own hydraulic power; applied water-power to his conservatory, that his plants might secure the sun. But amid all the luxuries which surround him, his life is as simple as nature; and now, at the ripe age of seventy-three, he maintains the freshness and elasticity of youth. He was wont to run like a deer along the moors of Allenheads to examine the target fired at by the original Armstrong gun.'

Lord Armstrong has been honoured both at home and abroad, and has done much for the amenity of Newcastle; and Jesmond Dene, part of his Jesmond estate, was thrown open to the public by the Prince of Wales while his guest at Cragside. The high-level bridge, giving easy access to the park for the town, cost 20,000. Other benefactions have been 12,500 towards a museum; a hall for the literary society, a mechanics' inst.i.tute, schools at Elswick, &c.

A recent purchase was at Bamborough, the ancient capital of the Northumbrian kings, where, nearer our own time, Grace Darling was born and died. Already great improvements are in progress there in the shape of workmen's houses; and the parish church is being restored. Bamborough Castle, which is also included in the purchase, is an imposing ma.s.s of masonry, standing on a pile of columnar basalt, which is mentioned early in history; there was a castle here as early as the fifth century. By the will of Lord Crewe it had been devoted as far back as 1721 to charitable purposes.

In the autumn of 1893, Lord Armstrong told the Elswick shareholders that he believed the time was coming when armoured ships would be as obsolete as mail-clad men. 'Do what we will,' he said, 'I believe that the means of attack will always overtake the means of defence, and that sooner or later armour will be abandoned.' His reason for this statement was the use of high explosives and quick-firing guns. In the future, light vessels of great speed, armed with quick-firing guns, are likely to be the order of the day. The life of a battleship, he also said, was far too valuable to be staked on the use of its ram; special ships should therefore be built for ramming. On another occasion he discussed the improvements in the manufacture of cordite which had made it possible to secure enormous power even with moderate-sized guns. With a 6-inch gun of 45 calibre, and a 100 lb. projectile, a velocity of nearly 3000 feet per second has been reached, giving an energy of 5884 tons, as against the 5254 tons of the 8-inch gun of ten years ago. This last gun could only fire four rounds in five minutes; now we hear of ten and eighteen rounds in three minutes. As to speed, some warships built for the Argentine Republic and for j.a.pan had reached a speed of 26-1/4 miles an hour, and were at the time the fastest war-vessels afloat.

At the annual meeting of shareholders in 1895, Lord Armstrong said that the war-material which they supplied for the great naval war in the East thoroughly stood the test, and the quick-firing guns of the j.a.panese navy had greatly helped their victory. The heavily-armed high-speed cruisers also deserve a share of the credit, and these had been built by their firm.

In connection with an official inquiry it was found that in 1896 there were 18,000 men employed in the a.r.s.enal at Elswick alone, and that 13 ironclads and cruisers, and 1400 guns were being built.

TESTING GUNS AT s...o...b..RYNESS.

It is at s...o...b..ryness, in the county of Ess.e.x, that experiments are carried out with the guns, large and small, manufactured at Woolwich and Enfield.

s...o...b..ryness has become a military centre, not because of any advantages afforded by its position on the sea, but because it consists of a large tract of dreary marshes flanked to the south and east by the far-stretching Maplin sands, which are almost entirely uncovered at low-water. These sands form the attraction from a scientific point of view.

The first connection of s...o...b..ryness with modern military matters appears to have been made so lately as the time of the Crimean War, when the flat rough marshland was employed as a camping ground for men and horses with the view of accustoming both to the hard work which lay before them in the East. This tract of country has thus become the property of the War Department, and that administrative body soon found another use for it, in which the half-submerged sands were to bear an important part. The idea was conceived that targets might be erected on these sands, and that the projectiles which were fired at them might be recovered at low-water. Hence the first connection of s...o...b..ryness with the artillery of the present day. A safe range can be found across the sands to almost any distance, and these marshes have therefore become the stage on which our great guns, such as Armstrongs and Whitworths, have made, so to speak, their first _debut_.

To reach s...o...b..ryness we take the railway which runs along the south coast of Ess.e.x and the northern bank of the Thames. As we near the mouth of the estuary we pa.s.s Southend, beloved of _trippers_, with its pier stretching out in its length of over a mile, and then cross the base of the ness itself, when we reach the sea again. On the south-eastern face of the ness we are at our journey's end, and the railway also, so far as the general public is concerned, has come to a full stop. We walk through the little town or village, and on the farther side find what we may call the original settlement of gunnery experiments, now for the most part a group of barracks and quarters such as we might find at any military station. A few differences we notice, however, for, as we pa.s.s through the barrack-yard, we observe that one building is labelled 'Lecture-room,' and other evidences there are here and there that the artillerymen who are quartered here are not altogether engaged in their ordinary duties. We shall probably not linger long at the barracks, but we shall not fail to observe that the officers' quarters and mess-room occupy an extremely pleasant position on a wooded bank above the sea, and that at high-water the waves come rippling up to the very trees themselves. Farther on are the houses appropriated to married officers, all alike situated on the pleasant sea-bank.

We see in front of us huge wooden erections standing on the edge of the sh.o.r.e. These are conning-towers from which, when practice is going on, a view is obtained of the direction of the shot. Beneath them are the batteries from which the guns are fired, and here go on the courses of instruction in practical artillery work, which are necessary for newly joined officers.

But we have by no means seen the most important part of s...o...b..ryness when we have visited the barracks and the batteries. We notice that a line of rails winds its way in and out amongst guns and storehouses, and if we have timed our visit right we shall find a little miniature train just about to start for what is called _The New Range_. Taking our places in this train we shall be carried first through the village and past the terminus of the public line, and then along a private railway which winds along amongst the corn-fields, until we reach a retired spot on the sea-sh.o.r.e hemmed in by lofty trees. In this private place are carried on all the experiments for which s...o...b..ryness is famous, and here both guns and explosives are tested to their utmost capability.

It is not altogether an unpicturesque spot at which we have arrived.

Grouped together in this immediate neighbourhood are certain nice old farmhouses and other buildings which have been taken possession of by the military. The s.p.a.ce in front would no doubt be an admirable rabbit-warren, only the whole ground is now covered by guns of various sizes, targets, shields, breastworks, and models of portions of ironclad and other vessels. Amongst these run lines of rails by which guns and materials can be moved to any part of the ground; and in places there are overhead travelling cranes by which heavy cannon may be hoisted on to or off from their carriages or into trucks, as need may require; and we again see lofty conning-towers, though target practice at a distance is not carried on here to the same extent as it is in that portion of the establishment which we first visited. The work at _The New Range_ is connected rather with experiments as to the force of explosives and the penetrating power of projectiles than with accuracy of aim and the direction of the shot.

We ought first to say a few words about modern explosives. Old-fashioned gunpowder, or _black_ powder as it is now usually called, is composed, as everybody knows, of saltpetre, charcoal, and sulphur mixed together in the proportion usually of seventy-five, fifteen, and ten parts respectively.

Two chief varieties of the new brown powders are now made, and are known as 'slow-burning cocoa'--from the fact that cocoa-nut fibres were first employed in the experiments--and 'Prism brown I.' The former contains about four per cent. of sulphur, and burns rather more rapidly than the latter, which contains only two per cent. Baked straw is the material now used to supplant the charcoal, as it provides a form of cellulose which may be readily reduced to a fine state of division. The shape is still the perforated hexagonal prism introduced in America.

The burning of these powders is steady and the increase of pressure gradual, attaining a maximum when the bullet is about half-way down the barrel of the gun. The damage inflicted on the firing-chamber is very slight; perhaps as slight as ever will be obtained with such large charges of powder.

Uniformity of velocity is secured by ensuring that in the making the proportions employed shall be accurate and the mixing complete. The prisms of any given cla.s.s of powder are made exactly the same in weight and composition, and in consequence, a charge composed of a given number of prisms will give in every case almost exactly the same propelling force. It is thus that fine aiming adjustments are made possible, as two consecutive bullets of the same weight may be propelled almost exactly the same distance--varying only a few yards in a range of several miles--by equal weights of powder of uniform composition.

But explosives of the present day are composed of other substances.

Cordite, of which we now hear so much, is made of nitro-glycerine, gun-cotton, and mineral jelly in the proportion of fifty-seven, thirty-eight, and five parts. It is also steeped in a preparation of acetone. Gun-cotton itself is dipped in a mixture of three parts of sulphuric to one of nitric acid. The force of cordite over gunpowder may be judged from the following facts. A cartridge containing seventy grains of black powder fired in the ordinary rifle of the army will give what is called a muzzle velocity of one thousand three hundred and fifty feet a second, while thirty grains only of cordite will give a velocity of two thousand feet. In larger arms, a little less than a pound of cordite fired in a twelve-pounder gun will give more velocity than four pounds of black powder fired in the same weapon. It need hardly be said that in the experiments at s...o...b..ryness it is the new-fashioned explosive which is chiefly used.

Let us examine one of the guns, a breech-loader, and see what improvements have been made which may conduce to rapidity of fire. We see that in the older pattern three motions were necessary to open the breech. First the bar which is fixed across the base of the block had to be removed, then a half turn had to be given to the block to free it in its bed, and then it had to be pulled forward. Firstly, it had to be thrown back on its hinge so as to open the gun from end to end. We are shown that in later patterns the cavity or bed into which the block fits is made in the form of a cone, so that the breech-block itself can be turned back without any preliminary motion forward. In artillery work, time is everything, and any one motion of the gunner's hands and arms saved is a point gained. Now let us look at the mechanism by which the recoil or backward movement of the gun is checked at the moment of firing. The gun slides in its cradle, and its recoil is counteracted by buffers which work in oil, something in the fashion of the oil springs which we see on doors. Iron spiral springs push the gun back again into place. Another interesting piece of mechanism is the electric machinery by which the gun is fired. When the recoil has taken place, the wire, along which runs the electric current, is pushed out of place, so that it is impossible to fire the gun, even though it be loaded, until it has been again fixed in its proper position on the cradle. Truly a modern cannon is a wonderful machine, and yet it is only a development from the sort of iron gas-pipe which was used in the middle ages. Hard by is a gun which has come to grief. In experiments which are carried on at s...o...b..ryness, guns are charged to their full, or, as in this case, more than their full strength. There is an ugly gash running down the outer case or jacket, as it is called, of the gun, and the latter has broken, and nearly jumped out of its cradle. Nursery phraseology certainly comes in strongly in the technical slang of gunnery when we have to do with _Woolwich Infants_.

After looking at the guns we naturally go on to look at the targets at which they are fired. Targets at _The New Range_ are not so much marks as specimens of armour-plates and other protections. Some of these are built up with a strength which to the uninitiated appears to be proof against any attack. Here, for instance, we find a steel plate of eighteen inches in thickness, and behind this six inches of iron, the whole backed up by huge balks of timber. But notwithstanding its depth, the enormous ma.s.s has been dented and cracked, and in places pierced.

When we look at plates which are not quite so thick, we see that the sh.e.l.ls have formed what are pretty and regular patterns, for small triangles of metal have been splintered off and turned back, so that the aperture is decorated with a circle of leaves, and resembles a rose with the centre cut out. Where the sh.e.l.l has entered the plate before it bursts, the pattern remains very perfect; but when it explodes as it touches the surface, some of the encircling leaves are entirely cut off.

One target is pointed out to us which represents the iron casing of the vulnerable portions of a torpedo boat, consisting of engine-room, boilers, and coal-bunkers. These compartments have been riddled again and again. Even a service-rifle bullet can penetrate one side, and a sh.e.l.l of the smallest size will go through both, for torpedo boats are not very heavily built.

HIRAM S. MAXIM AND THE MAXIM MACHINE GUN.

Statisticians inform us that the entire loss of life in wars between so-called civilised countries from the year 1793 down to 1877 had reached the enormous amount of four million four hundred and seventy thousand. To many persons these figures convey a sad and salutary lesson. But, leaving the sentimental part of the subject aside, all will readily unite in admiring the wonderful mechanism which makes the Maxim Machine Gun an engine of terrible destructiveness. Stanley provided himself with this formidable weapon, to be used defensively in the expedition on which he started for the relief of Emin Bey. It obtained a gold medal at the Inventions Exhibition, and has been approved of, if not actually adopted, by many governments.

[Ill.u.s.tration: Rifle-calibre Maxim Gun.]

Its rate of firing--770 shots a minute--is at least three times as rapid as that of any other machine gun. It has only a single barrel, which, when the shot is fired, recoils a distance of three-quarters of an inch on the other parts of the gun. This recoil sets moving the machinery which automatically keeps up a continuous fire at the extraordinary rate of 12 rounds a second. Each recoil of the barrel has therefore to perform the necessary functions of extracting and ejecting the empty cartridge, or bringing up the next full one and placing it in its proper position in the barrel, of c.o.c.king the hammer, and pulling the trigger.

As long as the firing continues, these functions are repeated round after round in succession. The barrel is provided with a water jacket, to prevent excessive heating; and is so mounted that it can be raised or lowered or set at any angle, or turned horizontally to the left or to the right. The bore is adapted to the present size of cartridges; and the maximum range is eighteen hundred yards. The gun can therefore be made to sweep a circle upwards of a mile in radius.

Nor is the gun excessively heavy, its total weight being only one hundred and six pounds, made up thus: Tripod, fifty pounds; pivot (on which the gun turns and by which it is attached to the tripod), sixteen pounds; gun and firing mechanism, forty pounds. The parts can be easily detached and conveniently folded for carriage, and may be put together again so quickly that, if the belt containing the cartridges is in position, the first shot can be delivered within ten seconds. It would therefore be extremely serviceable in preventing disaster through a body of troops being surprised. Reconnoitring parties, too, would deem it prudent to pay greater deference to an enemy's lonely sentry on advanced outpost duty if the latter were provided with this new Machine Gun, instead of the ordinary rifle.

Immediately below the barrel of the gun, a box is placed, containing the belt which carries the cartridges. The belts vary in length. Those commonly used are seven feet long, and capable of holding three hundred and thirty-three cartridges; shorter ones hold one hundred and twenty cartridges; but the several pieces can be joined together for continuous firing. Single shots can be fired at any time whether the belt is in position or not--in the former case by pressing a b.u.t.ton, which prevents the recoil; in the latter, by hand-loading in the ordinary way. To start firing, one end of the belt is inserted in the gun, the trigger is pulled by the hand once, after which the movement becomes continuous and automatic as long as the supply of cartridges lasts. At each recoil of the barrel, the belt is pushed sufficiently onward to bring the next cartridge into position; the mechanism grasps this cartridge, draws it from the belt, and pa.s.ses it on to the barrel. Should a faulty or an empty cartridge find its way in, and the gun does not go off in consequence, there is of course no recoil to keep up the repeating action, and the mechanism ceases to work until the obstruction is removed.

To devise and adjust the necessary parts of the machine with such precision that each part performs its proper function at the exact moment pre-arranged for it--to do all this while the gun fires at the enormous rate of six hundred rounds a minute, must have cost an immensity of thought, of labour, and of time.

The 'Colt Automatic Gun,' a new machine gun manufactured by the Colt Firearms Company, of Hartford, Connecticut, promised in 1896 to be a rival to the Maxim, as it fired 400 shots a minute.

Hiram S. Maxim was born in the state of Maine in 1840, and in his fourteenth year was apprenticed to a carriage-builder. From his father, who had a wood-working factory and mill, he learned the use of tools and derived his inventive turn of mind. After some experience in metal-working in his uncle's works at Fitchburg, he was in turn a philosophical instrument maker, and on the staff of some ironworkers and shipbuilders. About 1877 he became a consulting electrical engineer, a branch of science which he studied and became master of in a short time.

Some of the earliest electric lights in the States were devised and erected by him. He was in England and Europe in 1880 in order to investigate electrical methods there. He was back in London in 1883, and after that visit, like Siemens, he made it his headquarters. What leisure he now had (1883-4) on hand he devoted to inventing his automatic machine gun, which should load and fire itself, and the British government was the first to recognise its merits and adopt it.

The making of it has been taken over by the Maxim-Nordenfelt Gun Company, which has a capital of about two millions sterling.

Like Edison he has taken out about a hundred different patents, some of which are connected with oil motors and smokeless gunpowder. His flying-machine, as described in his paper at the British a.s.sociation in 1894, burns oil fuel, which developed three hundred and sixty horse-power. It was driven at sixty miles an hour horizontally, and the machine contained an aeroplane sloping six degrees to the horizon. The weight to be lifted was eight thousand pounds. After running nine hundred feet, the machine exerted an upward thrust of two thousand pounds greater than its own weight. The machine, after one thousand feet, broke loose; the steam was shut off, and it fell. The experiments have been conducted at Bexley, in Kent, where Mr Maxim had a light track of railway laid down, sixteen hundred feet long, on which the machine moved. The back part of the machine having been liberated from the check-rail too soon caused the accident at the experiment, and sent the whole machine off the track. There is sufficient evidence that it did rise from the ground, and Lords Rayleigh and Kelvin have become believers in its possibilities. This machine, as described at the time, with its four side sails and aeroplanes set, is over one hundred feet wide, and looks like a huge white bird with four wings instead of two.

It is propelled by two large two-bladed screws, resembling the screw-propellers of a ship, driven by two powerful compound engines.

IRONCLADS.

A modern ironclad is an enormous piece of complicated mechanism. In order to protect this mechanism from hostile shot, the greater part of it is placed under water and covered by a thick steel deck; the remainder above water being protected by vast armour-plates varying from eight to twenty-four inches in thickness. From the exterior, an ironclad is by no means a thing of beauty; one writer has described it as 'a cross between a cooking apparatus and a railway station;' but in place of this ingenious parallel, imagine a low flat-looking ma.s.s on the water; from the centre rises a huge funnel, on either side of which are a turret and a superstructure running to the bow and stern; two short pole masts, with platforms on the top for machine guns, complete an object calculated to bring tears to the eyes of the veteran sailor who remembers the days of the grand old line-of-battle ship, with its tall tapering masts and white sails glistening in the sun. A stranger going on board one of our newest types of ironclads would lose himself amid the intricacies and apparent confusion of the numerous engines, pa.s.sages, and compartments; it is a long time, in fact, before even the sailors find their way about these new ships; and the Admiralty allow a new ironclad to remain three months in harbour on first commissioning before going to sea, in order that the men may become acquainted with the uses of the several fittings on board, each ironclad that is built now being in many ways an improvement on its predecessor.

Those who have not been on board a modern ironclad can form no idea of the ma.s.siveness and solidity of the various fittings; the enormous guns, the rows of shot and sh.e.l.l, the huge bolts, bars, and beams seem to be meant for the use of giants, not men. Although crowded together in a comparatively small s.p.a.ce, everything is in perfect order, and ready at any moment to be used for offensive or defensive purposes. It is not, perhaps, generally known that the captain of a man-of-war is ordered to keep his ship properly prepared for battle as well in time of peace as of war. Every evening before dark the quarters are cleared and every arrangement made for night-battle, to prevent surprise by a better prepared enemy. When at anchor in a harbour, especially at night, the ship is always prepared to repel any attempts of an enemy to board or attack with torpedoes or fireships. In addition to the daily and weekly drills and exercises, once every three months the crew are exercised at night-quarters, the time of course being kept secret by the captain, so that no preparations can be made beforehand, the exercise being intended to represent a surprise. In the dead of night, when only the officers of the watch and the sentries posted in the various parts of the ship are awake, the notes of a bugle vibrate between the decks; immediately, as if by magic, everything becomes alive; men are seen scrambling out of their hammocks, and lights flash in all directions; the huge sh.e.l.ls are lifted by hydraulic power from the magazines, placed on trucks, and wheeled by means of railways to the turrets; men run here and there with rifles, boarding-pikes, axes, cases of powder and ammunition; others are engaged laying fire-hose along the decks, others closing the water-tight doors; while far down below, the engineers, stokers, and firemen are busy getting up steam for working the electric-light engines, turrets, &c. At the torpedo ports, the trained torpedo-men are placing the Whiteheads in their tubes; others are preparing cases of gun-cotton for boom-torpedoes. In ten minutes, however, all is again silent and each man stands at his station ready for action. The captain, followed by his princ.i.p.al officers, now walks round the quarters and inspects all the arrangements for battle, after which various exercises are gone through.

A bugle sounds, and numbers of men rush away to certain parts of the ship to repel imaginary boarders; another bugle, and a large party immediately commence to work the pumps; another low, long blast is a warning that the ship is about to ram an enemy, and every man on board stretches himself flat on the decks until the shock of the (supposed) collision takes place. After a number of exercises have been gone through, the guns are secured, arms and stores returned to their places, the men tumble into their hammocks again, and are soon fast asleep.

[Ill.u.s.tration: One of the 'Wooden Walls of Old England.' _The Duke of Wellington_ Screw Line-of-Battle Ship. One hundred and thirty-one Guns.]

It would be interesting to glance at some of the princ.i.p.al offensive and defensive capabilities of a modern ironclad. The first-cla.s.s line-of-battle ship of fifty years ago carried as many as a hundred and thirty, what would be called in the present day, very light guns; in contrast to this, her Majesty's armour-plated barbette ram _Benbow_ carries _two_ guns weighing a hundred and ten tons each. These enormous weapons are forty-three feet eight inches long, and are capable of sending a shot weighing three quarters of a ton to a distance of seven miles. The effect of a sh.e.l.l from one of these guns piercing the armour of a ship and bursting would be very disastrous, and there are few, if any, ships whose armour, when fairly hit at a moderate distance, could withstand such a blow.

Guns, however, although terrible in effect, are now supplemented by other and more deadly means of offence. Foremost amongst these stands the Whitehead or Fish Torpedo. This infernal machine can be discharged from tubes in the side of a ship to a distance of a thousand yards under water at a speed of twenty-five miles per hour. Armed with its charge of gun-cotton it rushes forth on its mission; and, if successful in striking the ship against which it is aimed, explodes, and rends a large hole in her side, through which the water pours in huge quant.i.ties. In order to protect a man-of-war from this danger, she can be surrounded at short notice with thick wire-nettings, hanging from projecting side-spars, against which the torpedo explodes with harmless effect.

These nettings are, however, princ.i.p.ally intended for use when ships are at anchor in harbour at night; they could not well be employed in action with an enemy, as they offer such resistance to the water as to reduce the speed of the ship by four or five knots, and so enc.u.mber her as to render her liable to be rammed by a more active opponent.

All large ironclads now have two or three torpedo boats. These craft are constructed of steel one-sixteenth of an inch thick, and steam at a speed of sixteen knots, some of the larger kind reaching twenty or twenty-one knots an hour. Carrying two Whiteheads, they are valuable auxiliaries to the parent ship; their rapid movements, together with their dangerous freight, distracting the attention of an enemy.

[Ill.u.s.tration: The _Majestic_.]

Machine-guns, however, form a very effective remedy for them; a single torpedo boat attacking an ironclad would, directly she got within range, be riddled with Gardner and Nordenfelt shot, and sunk in about fifteen seconds. It is only when three or four approach in various directions, or during night attacks, that they become really dangerous. The electric search-lights, with which most large men-of-war are now provided, will show a torpedo boat at the distance of a mile on the darkest night; but there is of course always a chance of their getting close enough to a ship to discharge a torpedo before they are discovered.

The bow of many of our ironclads is constructed for the purpose of ramming (running down and sinking) an antagonist. To use a ram requires great speed and facilities for turning and manoeuvring quickly; for the latter purposes, short ships are better than long ones. It would be a comparatively easy thing for a ship steaming fourteen knots to ram another that could only steam ten; a small ship might also outmanoeuvre and ram a long one; but it would be extremely difficult, in fact almost impossible, for a ship to ram another vessel of equal speed and length. To secure facilities in turning and manoeuvring, all our modern ships are built as short as possible, and have two screws, each worked by entirely separate sets of engines, so that one can go ahead whilst the other goes astern. If one set of engines is disabled, the other can still work independently, and a fair speed be maintained.

We always think that two ships at close quarters trying to ram one another, must be like a game at chess, requiring the closest observation of your opponent's movements and the nicest judgment for your own, a wrong move being fatal to either.