pieces, from 4 to 12-pounders. The quantity of powder used for the discharge of the several pieces in general warfare is— for common brass and iron guns, one-third the weight of powder to the ball, whatever the weight of the latter may be; for brass howitzers, which are the same in shape nearly as common cannon, being larger in the bore or inside and shorter in length, the quantity of powder used is one-ninth the weight of the ball; while in the firing of carronades, a still shorter and wider piece, the quantity of powder used is only one-twelfth the weight of the ball, being, as you will perceive, considerably less than what is used for common cannons.

By the use of something like this proportion, in several experiments which have been made, both at Woolwich and in France, where the several guns were directed point blank, that is, so as to fire the ball perfectly straight at the object aimed at, the largest class of cannon-balls was carried a range of 360 yards, and 18pounders as far as 400 yards, from iron guns ;—from brass guns, a 12-pound shot was sent 330 yards, and a 3-pound shot 350 yards; while from carronades, the range of shot was, of 68pounders 300 yards, of a 42-pound shot 270 yards, a 24-pound 250 yards, and of a 12-pound shot 230 yards. In general warfare, when what is called ricochet practice is often used, the most effective distances at which cannon can be used, is from 500 to 600 yards, or from a quarter to half a mile. At the battle of Waterloo, the brigades of artillery were stationed about half a mile from each other. Cannon and shells, however, can be thrown with effect to the distance of a mile and a half to two miles. From its destructive power it will naturally be supposed that some efforts have been made to ascertain what the force of gunpowder is when it causes a ball to strike any object.

The experiments have been numerous, and in Sir Howard Douglas's "Treatise on Naval Gunnery," it is recorded that several trials were made; in one instance, by firing an 18-pounder

shot into a butt made of beams of oak, when the charges were 6 lbs. of powder, 3 lbs., 24 lbs., and 1 lb., the respective depths of the penetration were 42 inches, 30 inches, 28 inches, and 15 inches, and the velocities at which the balls flew were 1600 feet in a second, 1140 feet, 1024 feet, and 656 feet. In 1835, in some experiments made at Woolwich, where balls were fired at a wall of concrete, that is, a composition of stone, made into a kind of cement, which hardens as it sets till it is harder than stone itself, two 24 lb. shot fired at a velocity of 1390 feet in a second, penetrated the wall to the depth of 3 feet 10 inches. When fired into wood, on account of the resistance of the fibres, which are driven forward by the ball, the depth reached by a large quantity of powder, exhibits less than the usual force. The knowledge of these facts is of great importance, as it enables engineers to judge of the strength of the erections constructed to resist the power of cannon, and thus preserve the lives and property of persons in besieged places. It should be further observed that in attacking fortifications, it is always necessary to elevate the mouths of the pieces, which fire the shot and shells, to the extent of from six to nine degrees of the arch of the horizon, the reason of which shall be explained hereafter.

Not only, however, is gunpowder employed in the discharge of deadly missiles above ground, but it is used to undermine the works of towns, and thus level their defences to allow the besiegers to enter. These mines which are formed for the defence of towns, are called defensive mines, and those formed by their opponents offensive mines.

There were formerly two kinds of mines used in the attack of a fortress. One was a subterranean passage, run under the walls, and charged with gunpowder, which being exploded, enabled the besiegers to enter, and thus attack the defenders in the very heart of their stronghold. The other was employed to demolish the walls themselves, and thus enable the attacking

force to bring all their power within the town, through the breach they had succeeded in making.

In the former case the business was to drive an underground way, or gallery as it was called, and at the end to deposit a quantity of combustible matter, which, being exploded at a certain time, opened the way for those attacking to enter the fortress. In the latter project, the gallery was driven till, by a peculiar instrument, it was ascertained that it had reached the walls of the place attacked, and then it was forced out right and left under their foundations, and supported by timber pillars. These were afterwards consumed by fire, and further shattered by powder, so that the support giving way, the walls fell into the gulf occasioned by the explosion.

These attempts were, however, often met by those who defended the fortifications, for the besieged were sometimes beforehand with their adversaries, and frequently met them face to face. Of this a remarkable instance occurred at the siege of a place called Melun in France, which was conducted by the Duke of Burgundy and our Henry V., in the year 1420. In that instance, the besiegers, who had driven up the mine close to the walls of the town, found, to their consternation and surprise, that their enemies had not been behindhand, and when the slight earthwork was broken through, and admitted an entrance into the town, the assailants perceived, with no little astonishment, their opponents ready to face them, and the king and the duke fought hand to hand with two of the inhabitants of the province of Dauphiny across the slight barrier that was left standing between the combatants.

Another of those terrible uses to which gunpowder is applied is the forcing open of the gates of fortified places, and a remarkable instance of the tremendous effect produced by it, was exhibited during the late war in India, when Afghanistan was overrun by the British forces. The long peace of Europe had thrown many of the military engineers out of employment, and

several had been taken into the service of the different potentates and princes of India. Among such as had retained some of these mercenaries, were the Ameers of Scinde, and when the dispute with the British East India Company broke out, they fortified Ghuznee, which was considered one of their strongest fortresses. Every effort had been used to render the place impregnable, and when their opponents approached, it was fully believed by those in possession, that it was quite strong enough to resist a siege of eight months, even if all the powers of artillery were brought against it, and all the balls fired that could be found in India.

The place was invested, and the ramparts presented a most imposing appearance; but the troops were posted, and Lord Keane, at that time in command of the British forces, determined to take the place by assault. About three hours before daylight the men were placed, and Lieut. Durand, of the 71st Highlanders, was commissioned to open the way for his comrades. The cannonade had been growing louder and louder for a couple of hours; and every moment the peals of the musketry, both from the walls and the assailants, became fiercer and fiercer. The Afghans burnt blue lights to ascertain the position of their foes; and, in one of the intervals of darkness, Durand advanced at the head of a party of men, each of whom bore on his shoulders a leathern bag filled with gunpowder. They succeeded in reaching the principal gate of the fortress without being observed: within were the Afghan soldiers appointed to guard the entrance, each smoking his pipe with the immovable gravity of Mahommedans, utterly unconscious of the tremendous catastrophe that was instantly to hurry them into eternity, and render all the precautions for the defence of the town useless.

The bags were quickly attached to the gate; the train was laid the fuze was lighted; Durand and his men hurried to a distance, and, in the next instant, there was a tremendous

explosion. The gate was scattered in fragments; the solid masonry of the walls, rent and torn, became a ruin; immense stones were hurled from their places; and all within the gate met with an instantaneous death. The way was opened; Colonel Denny, at the head of the forlorn hope, dashed over the ruins; and, notwithstanding the brave resistance of the defenders, the British flag soon waved over the ramparts.

Numerous examples of the powerful effects of gunpowder were given in that celebrated siege of Gibraltar, when it was assailed by the united forces of France and Spain, and defended by General Elliot. From its position at the entrance to the Mediterranean, Gibraltar has of late years been, as it will doubtless continue to be, a place of great political importance. It is connected on one side with the south-eastern coast of Spain; on its other sides the rock of the fortress bristling with cannon, and rough with the craggy protuberances by which its face is broken, towers in the highest part upwards of thirteen hundred feet above the waves that dash against its base, presenting one of the most formidable natural fortresses in the world.

Gibraltar had been taken by a combined English and Dutch fleet in 1704, and was confirmed as a British possession, in 1713, by the peace of Utrecht; but in 1779 it was assailed by the united forces of France and Spain, and the siege continued till the 2nd of February, 1783. The chief attack was made on the 13th September, 1782. On the part of the besiegers, besides stupendous batteries on the land side, mounting two hundred pieces of ordnance, there was an army of 40,000 men, under the command of the Duc de Crillon. In the bay lay the combined fleets of France and Spain, comprising fortyseven sail of the line, beside ten battering ships of powerful construction, that cost upwards of £50,000 each. From those the heaviest shells rebounded, but ultimately two of them were set on fire by red-hot shot, and the others were destroyed to prevent them from falling into the hands of the British com