« ПретходнаНастави »
Obs.--Of all the arts and professions which, at any time, attract notice, none appear more astonishing and marvellous than that of navigation, in the state in which it exists at present. This cannot be more evident, than by taking a retrospective view of the sipall craft to which navigation owes its origin; and comparing them to a majestic first rate, containing 1,000 men, with their provisions, drink, furniture, apparel, and other necessaries for many months, besides 100 pieces of beavy ordvance, and bearing all this vast apparatus safely to the most distant shores. A man in health consumes, in the space of twenty-four hours, about eight pounds of victuals and drink : consequently, 8,000lbs. of provisions are required daily in such a ship. Let us then suppose her to be fitted out for three months, and we shall find that she must be laden with 720,000lbs. of provisions. A large 42 pounder weigbs
about 6,100lbs., if made of brass, and about 5,500lbs., of iron; and generally there are twenty eight or thirty of these, on board a ship of 100 guns; the weight of which, exclusive of that of their carriages, amounts to 183,000lbs. On the second deck, thirty twenty four pounders ; each of which weighs about 5,100lbs., and therefore altogether, 153,000lbs.; and the weight of the twenty six or twenty eight twelve pounders on the lower deck, announts to about 75,400lbs.; that of the fourteen six pounders on the upper deck, to about 26,000lbs; and besides that, on the round tops, there are even three pounders and swivels. If to this we add, that the complete charge of a forty two pounder weighs about 64lbs., and that at least upwards of 100 charges are required for each gun, we shall find this to amount nearly to the same weight as the guns themselves. In addition also, to this, we must reflect, that every ship must have, by way of providing against exigencies, at least another set of sails, cables, cordage and tacklings, which altogether amount to a considerable weight; the stores, likewise, consisting, of planks, pitch and tow; the chests belonging to the officers and sailors; the surgeon's stores, and various other articles requisite on a long voyage; with the small arms, bayonets, swords and pistols, make no inconsiderable load; to which we must finally add, the weight of the crew: so that one of these large ships carries, at least, 2,162 tons burden, or 4,324,000lbs.; and at the same time, is steered and governed with as much ease as the smallest boat.
171. In Europe a fleet of ships of war is generally divided into three divisions; and commanded by admirals, vice admirals, or rear admirals, of the white, blue, and red flags. A ship is commanded by a captain, assisted by two, or in some instances, six lieutenants; under whom are from four to twelve midship
There are also a master and his mate, a boatswain and his mate, a purser, a surgeon, and a schoolmaster, with a captain of every gun.
172. There does not exist a more prodigious and wonderful combination of human industry, than is visible on board a first rate ship of war.
It appears incredible that a vessel, as large as the largest parish church, should be moved and directed in the water with nearly the same rapidity and precision as a small boat; and it is wonderful that human hands could have fabricated and put together such gigantic materials.
173. The immense ropes and cables consist of hemp spun together; the aggregation of timbers lately grew separately in the forests; the iron work was melted and prepared from the ore ; the cannon were cast in the foundry ; in short, the whole fabric has been assembled together by man from the raw productions of the earth!
174. Forts and castles are constructed of thick walls of brick, stone, or earth ; not built in straight lines, but projecting and indented so that one part may protect and cover another, and so that the walls may stand obliquely to the fire of an assailant. Forts are also provided with wet or dry ditches; and with mines under the adjacent ground, to blow up an approaching enemy
175. The projecting angle, or work of a fortification, is called a bastion.
The straight wall that joins bastions, and which these are to defend, is called the curtain.
The projecting angles are called salient angles ; and the angles which point inwards are called the reentering angles.
Works beyond the ditch are called out-works.
The sloping bank of earth all round is called the glacies.
The upper part of the wall is the parapet; and the walk within the wall is called the rampart.
Obs. In the cut, NL A F is a bastion.
176. No fortress can be prudently assaulted by besiegers within the range of its guns, except by digging an approach in a zigzag or slant direction, something like the capital Z; having approached in this way, a battery is raised in the night, and the attack begins.
Afterwards other zigzag approaches are made, called parallels ; and other batteries are constructed nearer and nearer,
till a breach is made, and the place taken by assault or capitulation.
177. The composition of gunpowder was first noticed by Roger Bacon, an English friar, in 1280; but Swartz, a German monk, applied it in projecting heavy bodies, about 1320.
The first cannon were used by Edward III. in 1346, at the battle of Cressey, and at the seige of Calais, in 1347.
Portable, cannon, called muskets, were first used by the Spaniards about 1500 ; but they were very clumsy, being supported by a rest from the ground, and fired by a match.
Locks of flint and steel, called firelocks were not introduced till the wars of William III. and Queen Anne.
178. A ball, at its discharge from a gun, meves in a velocity of twenty miles in a minute, or one mile in three seconds.
The distance depends on the weight of the ball, and the quantity and quality of the powder; but a ball goes the fartherest when the piece is elevated to an angle of 45 degrees ; and there are tables constructed for every degree of elevation.
In battle, it is found that not more than one ball in 60 does execution, owing to their rising, when they first leave the gun.
179. Formerly cannon were made so large, as to discharge stones of 100lbs. weight, to a distance of five or six miles, but it is now found that the largest convenient size is a 48 pounder; those carrying 24lb. shot are preferred.
Ship guns are from 48 to 3 pounders; guns in forts and castles are from 18 to 42 pounders; field pieces, or flying artillery, are 6, 9, or 12 pounders.
The best gunpowder is made of 25 parts of nitre, five of charcoal, and three of sulphur.
Obs. 1.- Before the invention of gunpowder, large stones, equal to mill stones, were thrown by machines called ballista; and battering rams were used to make breaches in the walls of cities.
2. The modern art of war, setting at defiance the means of destruction existing in fire arms and cannon, attains its objects chiefly by rapid movements, by breaking the line of battle, and by passing into the rear of the enemy,
seizing his Inagazines, and destroying his communications. The great victories of Bonaparte over the generals and potentates of Europe, were gained by these means.
3. On the dreadful subject of war, which ought never to be undertaken, except when unavoidable and in self defence, Porteus, bishop of London, wrote the following inpressive
-'Twas man himself