Steel from one-fifth to one per cent.

Wrought iron less than one-fifth per cent.

Mild steel, which has least carbon of all the varieties of steel and in this respect is therefore nearest to wrought iron, is used for the same purposes as wrought iron, such as shipbuilding, bridges and roofs, tanks, gas-holders, etc. When the Admiralty want a specially fast ship such as a torpedo-boat destroyer with a hull as light as possible consistent with strength they have it made of steel with a slightly larger percentage of carbon so that the steel is stronger and the vessel's frame can be made lighter. The steel for sh.e.l.ls, too, needs to be of a certain strength to give the best results, so the percentage of carbon is adjusted accordingly.

For guns themselves, again, special properties are needed, and so not only is the carbon regulated to a nicety but other things such as nickel and chromium are added. Altogether, steel is one of the most marvellous substances known, certainly the most marvellous metal. Copper is just copper and no more, zinc is just zinc, and the same with lead, but iron (which really includes steel) can be adapted to so many purposes, can be endowed at will with so many different properties, that without doubt iron, common, plentiful iron, is the king of all the metals.

CHAPTER VIII

MORE ABOUT GUNS

As has been remarked elsewhere, some of the guns used by the soldiers in land warfare are very different from those used in the navy. The latter, being carried on the ships to which they belong, can be of those proportions which best suit their purpose. Consequently they are usually very long compared with their diameter.

The field guns used by the Royal Field Artillery are shorter in proportion to their calibre than are the big naval guns. Otherwise they would be far too long to handle in the field. They are mounted on carriages drawn by horses, and are so handy that they can go anywhere where infantry can go and can travel just as fast. It takes a very short time to get them ready for action, too, so that they can accompany infantry quite freely, neither arm impeding the movements of the other.

The Horse Artillery, again, whose guns are even lighter still, can accompany cavalry, travelling as fast and coming into action almost as quickly as the troopers themselves.

The famous French "seventy-fives" (meaning 75 millimetres calibre) which played such a great part in the war, are field guns intended to move rapidly and to operate with infantry.

Both these types of gun were used by the British in South Africa, as also were some field howitzers, a type of gun to which further reference will be made later. But the Boers taught the world something new as to the possibilities of moving heavy guns quickly. Perhaps the reason for this was that they, being something of the nature of amateurs in the art of warfare, were less under the influence of tradition. Anyway, they surprised the British by the quick way in which they moved heavy guns, sometimes into quite difficult positions, over rough ground and up steep hills. These heavy guns of theirs were called by the British soldiers "Long Toms."

But the British were quick to respond, particularly the ever-resourceful navy. When the war broke out there were, in the neighbourhood of Durban, a number of warships which had as part of their own armament some of those guns which afterwards became famous as "47's," that being the diameter of the bore in inches. They were of the long shape usual in naval guns, and it is easy to see that they were much heavier than the field guns of 3 inches or so in diameter.

Captain Scott (now Admiral Sir Percy Scott) saw that these would be useful, so he quickly designed some carriages for them, got these made in the railway workshops at Durban, and in a few hours was rushing them up to Ladysmith. It was these guns very largely which enabled that town to hold out for so long, until, in fact, it was triumphantly relieved.

Thus the effect of the Boer war was to show that much heavier weapons could be manipulated in the field than had been considered possible before. The Great War which followed but a few years later carried on this same lesson, for one of the great surprises with which the Allies were confronted in the early days of the conflict was the inexplicable fall of fortresses which till then had been deemed almost impregnable.

Liege, Namur, Maubeuge and, finally, Antwerp, all fell to a wonderful gun of enormous dimensions which the Austrians had produced from up their sleeve, so to speak. Like conjurers they had kept them secret until the last moment.

These weapons which made history so fast were of the kind called howitzers, a name mentioned just now. It should be explained here that gunners talk of guns and howitzers as if the latter were not guns; but that is only a convenient habit which has grown up, for the latter are unquestionably guns. The distinction is, however, so convenient that we may well adopt it ourselves for the rest of this chapter.

Repeated references have been made already to the question of the length of guns, and it has been pointed out that to get high velocity, great range and vigorous. .h.i.tting power a gun needs to be as long as possible.

On ships this is only limited by the strength of the steel of which the gun is made, for beyond a certain length the gun bends of its own weight. Ash.o.r.e, however, the difficulties of transport impose a further limitation in most cases, although the famous 47, like many other naval guns, has a length of 50 calibres, and the guns of small calibre do approximate somewhat to the proportions of the naval guns, since even then their length comes within manageable limits.

Modern warfare, however, requires the use of larger sh.e.l.ls containing larger charges of explosives, and to fire these requires guns of greater calibre. We hear of sh.e.l.ls of as great a diameter as 16 inches being thrown into the Belgian fortresses and of course nothing smaller than a 16-inch gun could do that. Now a 16-inch gun, if made to the naval proportions of 50 calibres or even 45 calibres, would mean a length of at least 60 to 70 feet. It would also mean a weight exceeding 100 tons, for the 12-inch naval gun of 50 calibres weighs about 70 tons. And it is easy to see that such a gun would be very difficult to move on the field of battle. Indeed, it would be almost useless because of the time it would take to get it into position and to construct the foundations which it would need. If the Austrians had only had such as those the Belgians would have had plenty of time to prepare for them at Antwerp, whereas it was the quickness with which they brought up their heavy guns that astonished everyone and took their opponents by surprise.

The secret of this astonishing performance lies in the fact that they were not guns at all but howitzers, which instead of being long, slender tubes are short, fat ones, and that involves a different idea in gunnery altogether. The "gun" fires _at_ an object. The howitzer fires its sh.e.l.l upwards with the purpose of dropping it _upon_ the object.

The difference between the two is well ill.u.s.trated by the methods of practising with them. In learning to work a gun the gunners fire at a vertical target just as those of you who practise shooting at a miniature range fire at a target of paper placed vertically against a wall. The target for howitzer practice, on the other hand, is a square marked out on the level ground, and the object of the gunners is to see how great a proportion of a given number of shots they can drop inside that square.

Of course, being so much shorter the howitzers cannot throw a sh.e.l.l so far or at such a high velocity as the naval guns, but that can to a certain extent be compensated for by using a higher explosive for the propellant. That, however, involves greater stresses in the tube when firing takes place and also calls for stronger foundations in order that the aim may be steady.

A great part, too, of the velocity of a naval sh.e.l.l is required for the penetration of the armour, whereas against forts or earthworks it is sufficient if the sh.e.l.l "gets there."

Moreover, generally speaking, it is possible to get much nearer to a fortress or entrenched position for the purpose of attacking it than it is to an enemy ship on the sea. Except for the occasional help of a mist there is no "cover" to be obtained at sea, while on land the ground must be very flat indeed if there is no low hill or undulation behind which a gun can be set up unnoticed.

The Austrians cherish a piece of steelwork from one of the forts of Antwerp which they smashed with a sh.e.l.l from one of their big howitzers at a range of seven miles. They evidently were able to get their big howitzers within that comparatively short distance of the Antwerp fortifications without being molested.

[Ill.u.s.tration: A GERMAN AUTOMATIC PISTOL.

The action is fully described on the ill.u.s.tration.]

In this connection one often hears the word mortar used, and just a reference to that will be appropriate here. Many years ago short guns which threw their b.a.l.l.s very high were in use, and because of their resemblance to the mortar which is used for pounding up things with the aid of a pestle these were termed mortars. Later a man named Howitzer introduced a type of gun which was something of a compromise between the long thin gun and the short stubby mortar. As time has gone on, however, the mortars have grown in length while the howitzers have shortened, until to-day the two names are used almost indiscriminately to denote the same thing. Hence the giant howitzers of the Austrians are often spoken of as the "Skoda" mortars, Skoda being the name of the factory where they were made.

At one time many people wondered why the Germans did not put some of these huge mortars on their battleships: many thought that they would do so, and that by that means they would demolish our navy as they had already smashed the Belgian forts. The reason they did not is, no doubt, the very simple one, that our naval guns would have probably sunk their ships before the howitzers could have reached ours, because if they had attempted to make up for the shortness of the weapons by using higher explosives, these mortars would, there is little doubt, have knocked to pieces the ships on which they were mounted.

The old-fashioned fortress, suddenly made "out-of-date" by the Skoda mortars, was usually armed with guns of the naval type. Sea-coast forts are always so armed. Nowadays, however, the inland fortress takes the form of a labyrinth of trenches and underground pa.s.sages, combined with deeply excavated chambers known as dug-outs, and these do not fitly accommodate large guns at all. The guns are placed well back behind the trenches sheltered behind hills or woods, over which they hurl their sh.e.l.ls. The chief defenders of the actual trench are the machine gun, which is little more than an automatic rifle on a stand, and the trench mortar.

We are now in a position to sum up broadly the features of modern artillery. There is first the naval gun, the ideal gun, long and of great range, able to send forth its sh.e.l.ls with great velocity. This gun appears again in the sea-coast forts, where the conditions are very much those which obtain on a ship and where the attacking party is of necessity a ship.

In the field we have the field and horse artillery, which we may regard as the naval gun modified somewhat in order to make it easy to move about, so that it can accompany troops and support the operations of both infantry and cavalry. These light guns are supported by the field howitzers, which are also light and easily handled, and the guns of the 47 type, originally naval guns but now mounted on wheels and possessing a certain amount of mobility, not equalling the field guns it is true, but still very serviceable in a campaign.

Then we have the howitzers of various sizes which have rendered the old-fashioned steel and concrete forts useless, and which are the chief weapons used in the modern trench warfare. It is these which blow in the walls of the trenches and dug-outs, shatter the barbed-wire entanglements and render it possible for the infantry to attack an entrenched position.

Finally, we have the machine guns, each of which is equivalent to a considerable number of riflemen and which, with the trench mortars, form the chief defences of the actual trench itself. Of course these are only useful against attacks by infantry: they cannot in any way cope with the heavy artillery. That has to be dealt with by the opposing artillery posted away back behind the trenches.

And now let us take a rather more close look at some of these weapons.

Essentially each one is a steel tube. It may be a single tube or it may be several one outside another. It may even have a layer of wire between two tubes as many naval guns have. It is invariably (one small exception will be mentioned later) loaded at the breech or rear end and not through the muzzle as used to be the custom. For this purpose it needs a breech-block or door, which can be opened to put in the sh.e.l.l and explosive, and which can then be closed tightly so that it will not be driven out or burst open when the explosion takes place and also shall be gas tight so as not to let any of the force of the explosion escape.

Then the gun must be mounted upon a carriage so that it can be quickly moved about. The lighter forms of artillery are fired when upon the same carriage upon which they travel. In years gone by the whole thing, carriage as well as gun, used to run back when the gun was fired, which was a great nuisance since it had to be got back into position again after each shot. To obviate this the gun is now mounted upon a slide, and it is the slide which is fitted to the carriage. Thus the gun can slide back without the carriage moving at all. The latter is made very strong, and shoes are provided at the end of chains which go under the wheels just like the "drag" which coaches and heavy carts have for use going down hills. There is also a part like a spade which can be driven down into the ground so that, what with the shoes and the spade, the carriage is fixed very firmly.

The gun is kept at the front part of the slide by means of a powerful spring, which is compressed when the gun is fired but which, as the force of the recoil is spent, pushes the gun back to its original position once more. The spring is often reinforced by a cylinder and a piston with compressed air or water behind it, acting after the manner of those door checks with which we are all familiar, its function being to steady the motion of the gun and to let it go gently back to its place without slamming, just as the door check prevents a door from slamming.

By this means the gun is returned automatically after each shot to practically the same position which it occupied before, so that it does not need re-aiming each time, but only a slight readjustment if even that. The result of this is that such a gun can be fired very rapidly.

In fact, it can be fired just as fast as the gunners can keep on reloading it.

The big Skoda mortars owed their mobility to the clever way in which they were constructed. The gun tube itself, the support for it or mounting, and the steel foundation were each fitted to a special motor-driven trolley. The steel foundation was dumped down on the ground, which of course was prepared for it in advance, then the mounting was run right on to it so that it simply needed bolting down and finally the tube was hoisted by specially prepared appliances into its place. It is said that the whole operation occupied less than an hour.

For firing, these mortars of course are pointed at a very high angle, almost like an astronomical telescope. No doubt the gunners have many jokes about "shooting the moon" and so on, for that is just what they seem to be attempting. For loading, however, they are lowered into a horizontal position: the sh.e.l.l comes up on a small hand-truck, is raised by a specially designed jack until it is level with the breech, and is then pushed into its place. The breech is then closed, the tube re-elevated, and all is ready for firing.

Between these two forms of gun, the field gun on its light carriage, which not only bears it from place to place but forms its support while in action, and the great mortar carried in parts on specially made trolleys, there are now an enormous variety of guns and mortars adapted for the various purposes which experience in the Great War revealed.

Artillery suffered many changes in the light of the South African campaign and of the Russo-j.a.panese war, but of far more importance have been the lessons learnt in Northern France and on the plains of Poland.

To some extent these lessons have been learnt and profited by during the actual war, but there is no doubt that as men have time to think over them in the years of peace which are ahead many more developments will take place. Unless, that is, we are on the threshold of that happy time when guns and fighting material of all sorts will be looked upon as the relics of a bad and ruinous time now happily past.

In conclusion, a pa.s.sing reference must be made to the trench mortars and similar contrivances which have arisen as the result of the prolonged spell of trench warfare which no one had ever contemplated.

These are in effect very short range mortars or howitzers, specially intended for throwing bombs from trench to trench. Some are simply the larger mortars on a small scale, but one has decidedly original features.

This consists of a short light mortar into which the bombs are slipped through the muzzle, thus reverting to the old method of loading. The propellant is combined with the bomb and there is a percussion cap which fires it as soon as it strikes the bottom of the tube. Thus the operation is just about as simple as it can be: the man merely places the bomb in the upturned muzzle and lets it slide down. An instant later, up it comes again, to go sailing through the air into the trench of the enemy a hundred yards away.

One must not conclude this chapter, however, without a reference to those useful weapons which are known among the soldiers as "Archibalds"

and officially as anti-aircraft guns. These are perhaps the most familiar guns of all to the general public, since they were installed in many places in Britain for the purpose of dealing with the Zeppelins. No doubt not a few of my readers have had the experience of being awakened from their beauty sleep by the cracking of the anti-aircraft guns and have seen their sh.e.l.ls bursting like squibs in the air.

They are fairly long guns, not unlike field guns, but they are mounted upon special supports which enable them to be pointed at any angle so that they can fire right up into the sky. The sights, also, are somewhat different, being fitted with prisms, or reflectors, so that the gunners can look along the sights and align the gun upon an object overhead without lying on their backs.

Much more could be said on this subject, but national interests forbid, so with this general review of modern artillery we must pa.s.s to another subject.