firing-hole, and either smooth in the interior, or if great accuracy is required, when intended to be used with ball, grooved in a spiral direction. Here, then, we have one great subdivision into smooth bores and rifles, the former being used with shot or ball, while the latter is intended for ball only. But in addition to this subdivision, we have also another most important one, and gradually becoming more so every year. This consists in the method of putting in the charge, which may be either at the muzzle, and the guns are then called muzzle-loaders, or at the breech, when they are denominated breech-loaders.

SHOT-GUNS CONSIST OF A TUBE MORE OR LESS CYLINDRO

CONOIDAL, CLOSED AT ONE END.

Whatever may be the method of firing and loading adopted, every shot-gun is composed of a tube of iron, bored so as to represent a cylinder in the greater part of its extent, but more or less conical in the remainder. One end is left open, to allow of the shot escaping when the explosion behind it takes place; the other is closed either by a plug of iron being screwed into it, as in the ordinary muzzle-loader, or by some method to supply the place of this solid breeching, after the charge is introduced at the breech end. Besides the cylinder or barrel, as it is called, there is also a provision for the explosion of the powder, which is effected in different ways, according to the kind of gun which is to be employed. Lastly, the barrels must be made capable of being handled quickly, and applied to the eye so as to get a "sight" of the object against which they are to be directed, and for this purpose a wooden handle called a "stock" is provided, so shaped as to be adapted to the individual for whom it is intended. Here, then, we have the gun divided into the barrel, which is the essential part, the lock which provides for the firing of its charge, and the stock which is added to attach these two together, and also to allow of the adjustment of the barrel in a straight line with the mark to be hit.

In the early part of this century, and during the whole of the last, the gun used for sporting purposes was that known

as the flint-gun. This was a similar tube to that now used, as far as its principle of action is concerned, with the exception that the charge was fired by means of a spark (arising from the striking together of flint and steel), which fell into a small cup of powder outside the barrel, but communicating with its interior through a small canal (the touch-hole) also filled with gunpowder. By means of this comparatively rude invention, the sportsmen of that day were able to shoot flying, but not with the same accuracy as at present; and the practice required to make a good shot" was ten times as great as with the percussion gun. The explosion was much longer about, and the aim was consequently behind the object, unless allowance was made for the loss of time, which would necessarily vary greatly according to distance. The same principle of allowing for loss of time is still required, but this is now so trifling, that by aiming at a hare's head, the shoulder will be struck, and the same proportion will hold good with flying objects.

BARRELS.

Though the barrels of all guns and rifles are of iron, they are not all made in the same way, or of material corresponding in strength. In the infancy of the art, a flat piece, or sometimes two pieces of iron, were welded longitudinally round a mandril into a tube, but in process of time it was discovered that by twisting narrow strips of iron spirally round, and welding these together, a much stronger tube was produced with less metal. This plan is therefore adopted in the present day in all the best guns, and in rifles where weight is objectionable. In these latter guns, however, a solid bar of steel is sometimes perforated and grooved, but weight for weight it will not compete with the twisted barrel.

THE GAUGE.

All guns are measured according to their diameter, which is technically called the gauge or calibre. There are two ways of estimating this, first according to the weight of a spherical leaden ball which will fit the gauge, and secondly, according to the diameter in decimal parts of an inch.

The former is always adopted with shot-guns and sporting rifles, while the latter is generally applied to military arms. Thus a gun of 12 gauge carries a ball weighing the twelfth part of a pound avoirdupois; a 14 gauge carries one of fourteen to the pound, and so on. For sporting purposes, shot-guns are now generally made of 12 or 14 bore; but where great lightness is required, 16 or 18 even may be adopted. These gauges measure severally in inches or parts of an inch, as shown in the opposite table:—

It is therefore easy for any one knowing the gauge of his gun or rifle to get an approximate idea of its diameter in inches; and on the other hand, if the diameter is known in inches, a sufficiently accurate guess for practical purposes may be made at its gauge, or in other words, at the weight of the spherical ball which it will carry. The diameter of the intermediate gauges is not exactly in proportion to those above and below, as the scale between 4 and 16 does not descend in a straight line, but in a slightly concave one. Without actual measurement, therefore, the precise diameter in decimal parts of an inch cannot be given, but for practical purposes the fractional parts here introduced are sufficient.

LOCKS.

The first spring locks for the use of the flint-gun were made in the beginning of the sixteenth century, but they were rude in the extreme, and though they effected the discharge of the gun, they took their time to do it. Previously to this, the powder was exploded by a match, which would forbid the use of the barrel except towards sitting objects. The spring flint-lock was therefore a considerable step, and by the aid of various clever inventors, it was brought to great perfection. Indeed, so useful and deadly was the flint-gun in the time of the Mantons, that they were long before they could be induced to adopt the next invention, to which we are now indebted for the quick shooting which all our modern kinds give. This was the discovery of the mode of firing gunpowder by exploding close to it a small quantity of a composition which would take fire on being sharply struck with a hard body. From this circumstance the plan was called the per

cussion principle, although the flint equally requires percussion with the steel to elicit the spark which drops into the powder and ignites it. But in the former case there is no necessity for an external reservoir of powder, and the blow of the hammer is more evidently the cause of the explosion; so that though there is no great difference between the principles of the two methods, it is apparently very considerable, and in practice it really is so. But whether the name is correctly given or not, the plan was introduced, and is now universally employed, a flint-gun in the present day being only occasionally kept as a curiosity, and an order for one being as great a rarity as the Koh-i-noor.

The Forsyth lock, which was the first on the percussion principle, was brought out by its inventor, a clergyman, resident at Bethelvie, under very good patronage, and with high-sounding pretensions. An advertisement announced to the world that a gun had been invented which went off without flash or smoke, and that consequently "flash in the pans" would be hereafter unknown. Now, every sportsman up to that time was constantly annoyed by these little accidents, and therefore the novelty was accepted by all but those bigoted to old-fashioned ways, simply because they are old, as a step in the right direction. The plan was proposed soon after the discovery of the new fulminating powders, which are now so well known, and it was used by means of a small magazine which held enough powder to effect thirty discharges. But in practice it was open to the objection that sometimes the quantity was too small, and at others the whole of it contained in the magazine exploded; again, the tube leading to the powder was small and with a sharp angle in it, so that missfires were almost as common as with the old flint lock.

MODES OF EXPLODING.

The Invention of the Percussion Cap has been the greatest improvement in firearms during the present century; for, though it is not outwardly apparent, yet in almost every variety of shot-gun or rifle it is now employed in some shape or other. Lancaster's needle-gun, it is true, has no