This lid would of itself be far from secure the discharge of the piece would instantly blow it out. It is useful chiefly in loading. There is a hole in its centre, through which a rod works as in the cylinder of a steam-engine, and attached to this rod is a piston. This rod, with piston, indeed forms a short ramrod. We shall suppose the charge deposited by hand in the mouth of the bore behind. The lid is then shut, and the rod is pushed in about eighteen inches, driving the charge before it. The ramrod forms the breech, and is allowed to remain in this position till the piece is discharged. The beauty of the contrivance, however, consists in the method by which the breech is prevented from being blown out. This is effected by running a bolt transversely through the cannon, and immediately behind the piston. The bolt is a solid iron cylinder, with a diameter nearly equal to that of the bore of the piece. The ramrod, at this point, assumes the form of a ring to let the bolt pass through. It is obvious that the whole strain of the charge is laid upon this transverse bolt; and, looking at the piece, you would say that it must be as strong as if it had a solid breech. The young officer above alluded to, however informed me, that in a recent trial of a similar gun the cylinder was broken across, and two men killed. The blame was laid upon the imperfection of the iron of which the cylinder was made. It is pretty obvious, however, that perfect security has not yet been gained, so that the general adoption of the plan of loading at the breech cannot in the meantime be expected. Notwithstanding this, the great advantage of this plan is so obvious, that there can be little doubt that all practical difficulties will soon be overcome. The practical difficulty in the case of small arms is not nearly so great, and the plan is already pretty extensively adopted. It must be remarked, that the idea of loading at the breech is only the revival of older contrivances for effecting the same object.

Could steam be conveniently applied instead of gunpowder, the demand for rapidity could easily be met. I have seen a steam musket discharge bullets at the rate of nearly one every second. They were discharged as rapidly as a man could work the steam valves. Here no time is lost in charging the weapon with its explosive power. The case is similar with an air-gun where there is a magazine of condensed air, and the necessity of charging for each shot is superseded. The same object is accomplished in some measure by the far-famed weapon so intimately associated with the history and character of our transatlantic cousins. I allude to Colonel Colt's revolver. A good many specimens both of American and English manufacture were exhibited, and if we can judge from the crowds that were constantly examining them, there were few things in the Exhibition so popular. The object of the revolver is to effect repeated discharges without the necessity of repriming and reloading. A person with such a weapon can fire seven or eight shots as fast as he can draw the trigger. The act of putting the weapon on cock brings a fresh charge into action. There is but one barrel, but then there are several breeches, or rather one compound breech, and the object of the mechanism is to apply the barrel successively to these several breeches. If you take the half of a pretty large apple, and, on the flat

side, make seven or eight holes round the circumference, sufficiently large to admit the finger, you will have a pretty fair idea of the compound breech. On examining the weapon, you saw the barrel applied to one of these holes or breeches, and each of the other breeches charged with a bullet which was rammed home by an ingenious lever contrivance.

The revolver was looked upon as a great novelty, but there is no doubt that it is a very old contrivance. Jonathan was rather startled to learn, that this, his own peculiar weapon, was found as an antiquarian curiosity in an English museum. Colonel Colt had himself the candour to acknowledge this. Nay, he made the subject a matter of antiquarian research, and found that there had been similar contrivances at various periods of English history, and that one of these dated as far back as Charles II. This discovery however by no means robs Colonel Colt of any merit there may be in his revolver. The most brilliant inventions of modern times would be robbed of their lustre if all merit was denied them on the discovery that similar contrivances existed in embryo at a former period. It is rarely indeed, that an invention is made without having antecedents to which it bears a very close relationship.

The above contrivances have reference merely to the rapidity of discharge. The other contrivances in the Exhibition bore chiefly upon the force of explosion and the accuracy of aim. In discharging fire-arms in the ordinary way, a great deal of the force of the powder is lost, as it is expelled without being burned. If the ignition takes place from behind, the generation of the gas is so rapid, that the powder in front is expelled without being consumed. This is obviated in the needle-gun of Prussia, by igniting the powder in front. There is detonating powder put in along with the charge, and in front of it. When the trigger is drawn the needle is struck against the detonating powder and explodes it. The charge being thus ignited in front burns backwards, and thus the consumption of the whole is secured. This contrivance is found to give a large increase in the range.

It is found too that the range depends greatly on the shape of the ball. When a body is projected through the air with a small velocity, the shape is of little moment, as the resistance of the air is trifling. The resistance increases prodigiously at high velocities, so that the shape becomes a most important element. It is found accordingly that an elongated ball can be projected with a given force much farther than a spherical one of the same weight, the former presenting a smaller surface to the resisting air.

The chief improvement in fire-arms consists in the contrivances for securing accuracy of flight,-which is sometimes confounded with range. One great source of divergence in a ball is the circumstance that it acquires a rotatory motion by its friction against the barrel when discharged. This rotation will increase the resistance of the air on one side and diminish it on the other, and the ball will of course tend to the side of least resistance, and diverge from a straight course. There is only one axis of rotation which does not interfere with the accuracy of the flight, viz. the axis which is coincident with the axis of the barrel, or the line of flight. Now the object of rifling is to compel the ball to rotate

on this axis. As there must be rotation, the rifle secures that it will not be such a rotation as will impair the accuracy of the aim. The mere rifling does not, as is often supposed, increase the range. A smooth barrel, cœteris paribus, carries farther than a rifle, but from the accuracy of aim the latter is serviceable at a much greater distance.

In

The rotation of the ball on the proper axis is secured by cutting spiral grooves in the interior of the barrel. The barrel is virtually a female screw, and the ball is the male screw. The thread upon the ball is cut in various ways, besides being sometimes formed in the mould. the common rifle the ball is a little larger than the free bore, and the thread is cut in the soft lead by the act of forcing it down. When the piece loads at the breech the thread is cut in the course of expulsion ;— the ball in this case being also somewhat larger than the bore. Another method consists in using a ball the size of the bore, and then after it is rammed home, squeezing it out to fill the grooves by striking the ramrod with a mallet. The ball rests on a tige or steel pillar projecting through the powder, and the expansion is caused by the pressure communicated by the blow of the mallet. Still another method is to make the ball hollow behind, so that when the piece is discharged, the thin rim of lead may expand and fill up the female threads or grooves, and also prevent all windage. In this case the ball need not be larger than the bore, so that time may be saved by dispensing with the mallet. The hollow behind is the distinguishing feature of the Miniè rifle. The other features of this rifle are due to prior improvers of the weapon.

We have said that in the case even of a perfect sphere, the circum. stance of rotation on an improper axis would be sufficient to throw the ball out of the right line ;-but divergence is also caused by any inequality of the surface. This source of error is destroyed by the rotation due to the rifling. A bent arrow will incline in its flight to the side towards which it bends. If, however, it be so feathered as to rotate on its long axis this tendency is destroyed. The bomerang, the throwing of which used to be a favourite exercise in my early days in the College Green of Glasgow, affords a good illustration of the divergence caused by the unequal action of the resisting air. The divergence of this weapon can be so accurately calculated, that you may hit an object round a corner and out of sight. The rotation of the ball, by distributing the tendency to error on all sides, makes the ball go truly in a straight line, or rather in the same plain. The improved elongated ball is also so shaped that the resistance of the air may tend to keep it in the right position. The fore part of the ball is a cone, and the hinder a cylinder, the size of the bore; the cylinder being in the most improved form, very short, or almost altogether wanting. The ball is thus kept steady in its course, very much for the same reason that the narrowest part of a vane keeps always to the wind. The hollow behind throws the centre of gravity forwards, which also tends to keep the long axis of the ball in the line of flight. A boy's whipping-top gives a very good idea of the improved ball. The shape is very much the same, and the spinning of the top is identical with that of the ball, and serves very much the same purpose.

While on the subject of rifles, I cannot omit to mention the ingenious application of the telescope to improve the accuracy of air. In taking

aim with the ordinary sights upon the barrel, three objects at different distances must be put in a line with one another, viz. the two sights upon the barrel, and the object aimed at. In the improvement to which I refer, only two objects have to be viewed at the same moment by the eye, and these are at the same distance, so that the same adjustment of the eye suits both of them. This object is accomplished by fixing on the barrel a small telescope through which the aim is taken. In taking aim all that is to be done is to look through the telescope, and place the object aimed at, or rather its image, over the cross in the focus of the eye-glass. This small telescope corresponds precisely to the finder attached to large telescopes for the purpose of pointing them accurately to any celestial object.

The improvement in fire-arms no doubt tends, as I have said, to lessen the bloody character of war, by bringing battles to a quicker termination. But it is not difficult to recognise another way in which it may tend to bring about a reign of peace. The profession of arms has always been surrounded by a factitious glory. In the past history of the world, the soldier has been the hero in every tale of romance. His deeds in arms have been the staple subject for the poet's genius; and in every country the honours of the State have been almost completely honopolized by the warrior. Almost every hereditary title can be

traced back to heroic deeds in arms. It cannot be wondered at that the profession of arms should be looked upon with such favour, and that the love of military glory should sometimes plunge nations into wars which a wise calculating policy would shrink from. The cure of this state of things would then be to divest war of this glory which so often blinds nations to their best interests. Now, science seems to be gradually working out this desired result; and it is doing this by superseding personal prowess by mechanical and chemical ingenuity. When war becomes a matter purely of projectiles and explosive compounds, the moral qualities of military heroism will be thrown very much in the background. The work will be done at a distance, and in masses, so that there will be little opportunity for the display of individual chivalry. The tendency of recent improvements is to make the fate of battles turn almost exclusively upon projectiles discharged at a great distance, before there is any opportunity of a hand-to-hand engagement; and when this tendency is fully realised, we doubt not that war will be very much stripped of its glory; and when this is done, one of the greatest temptations to war will be removed. War may still be necessary. The comity of nations may still demand the exercise of this dreadful scourge; but the matter will be looked upon in the light of a judicial execution. There will be then no more glory in mowing down the ranks of the enemy with shrapnel shells and hollow cylindro-conical bullets, than in working the guillotine. The soldier will sink down to the level of the executioner; a needful functionary, no doubt, but one usually not invested with much enviable glory. At present we see young men, brought up in the lap of luxury, eager to join a profession which is subject to restraints and discomforts as severe as those of a convicted felon, and all this for the sake of the glory attached to the profession of arms. But if the soldier

is to sink into the scientific executioner, this glory will soon vanish, and one of the greatest incitements to war will be thus extinguished. If we look to the French nation, we shall find abundant proof that the most bloody wars have been due to the false glory attached to a military life. The warlike spirit has often plunged them in the direst bloodshed, when the most obvious interests of the nation dictated peace. I must confess I felt an involuntary shudder when examining the many lethal weapons in the Exhibition; but yet I saw reason to adore the unspeakable wisdom of Him who brings good out of evil, and makes even the wrath of man to praise him.

I shall turn now to a more congenial subject from the sword to the ploughshare-from the spear to the pruning-hook. The agricultural department of the Exhibition was allowed to be one of the most complete. The exhibitors were in the practice of exhibiting their implements at agricultural shows, so that they were quite prepared for the requirements of the Crystal Palace. It wore by far the most businesslike aspect. In other departments you only saw listless loiterers, or people gazing in aimless wonder; but here you plainly saw that the implements were carefully scrutinised, for some ulterior object, by the multitudes that thronged the section. I had little conception that ingenuity had been so fertile in contrivances for the better cultivation of the soil. In the American department, the reaping machine of M'Cormick attracted great attention. Much, however, of the interest arose from the ignorance of the fact that similar machines were already tried, and that this one could be regarded as a novelty only in regard to subordinate details. This machine consists of a long straight blade, to which a forward and oscillating motion is communicated by horse power. It acts precisely as a knife does in cutting a slice of bread. The bread could not be readily cut if the knife was merely pressed forward horizontally against the bread. In order to facilitate the cutting, a sawing motion is given to the knife, which slips easily along. In the case of corn cutting, the long blade would not serve the purpose if it was merely carried forward and pressed against the stalks of corn. They would bend sooner than be cut. In order to obviate this, a very rapid sawing or oscillating motion is given to the blade. In the rival machine of Hussey, the cutting action is similar to that of a pair of scissors, so that the cutting edge gets a firmer gripe of the straw. If we may judge from the analogy of other departments of mechanical invention, we would be disposed to regard both the machines as indicative of a retrograde movement. We shall almost invariably find that the greatest achievements have been accomplished by converting a reciprocating motion into a circular and continuous one. The printing-press affords a good illustration of this. The triumph of Applegarth's machine consists in substituting a continuous drum for a flat form, so that the printed sheet comes out in an uninterrupted stream. We see the same thing in paper-making: a continuous web of paper is obtained, instead of the single sheets as in the old process. The calendering machine, as contrasted with the domestic smoothing-iron, furnishes a familiar illustration of this. The paddles of the steamer also, as contrasted with the oar, will immediately occur to