Permanent powder magazines. According to Vauban’s plan, powder magazines are commonly made 10 fathoms long, and 25 feet wide, in the clear. The foundation of the longest sides, is 9 or 10 feet thick, and 6 feet or more deep, according to the nature of the ground. The side walls raised upon these are 8 or 9 feet thick; and if there is not to be an upper story, 8 feet will be sufficient height above the foundation. By this means the flooring may be raised above the ground, free from damp, and there will remain 6 feet from the floor to the spring of the arch. The arch is formed of layers of bricks, arched one over the other, and ought to be 3 feet thick at the top. The exterior surface of the arch terminates with an angle at top, like a roof; which angle must be of such magnitude as to make a thickness of 8 feet over the key stone of the arch. The foundation at the gable ends is 5 feet thick, and the same depth as the sides; these ends are built up 4 feet thick, from the foundation to the top of the roof. The long sides are supported by counterforts, 6 feet thick and 4 feet long; and placed 12 feet asunder. The ventilators are placed, one in the centre of each space between the counterforts, and are made with a die across them of 1¹⁄₂ feet. These ventilators are also closed with plates of iron. The magazine is lighted by a window in each end, high up, which are opened and shut by means of a ladder. These windows are secured, each by two shutters, made of plank 2 or 3 inches thick; and the outer one covered with sheet iron, and both fastened with strong bolts. The entrance to the magazine is closed by two doors, one of which opens inwards, and the other outwards; the outward one is covered with sheet iron. The entrance of the magazine should, if possible, be placed towards the south. A wall of 1¹⁄₂ feet thick, and 10 feet high, is built round the magazine at 12 feet distance. A magazine of the above dimensions will contain about 94,800 lbs. of powder, in piles of 3 barrels each; for a greater number piled above each other destroys the barrels, damages the powder, and occasions accidents.
MAGNITUDE, or quantity, any thing locally continued, or that has several dimensions. Its origin is a point, which though void of parts, yet its flux forms a line, the flux of that a surface, and of that a body, &c.
MAGNA CHARTA, the great charter of liberties granted to the people of England in the 9th year of Henry III. and confirmed by Edward I. It is so called on account of the supposed excellence of the laws therein contained; or according to some writers, because another lesser charter, called Charter de Foresta, was established with it; or because it contained more than any other charter, &c. or in regard of the remarkable solemnity in the denouncing excommunications against the infringers of it. It is nevertheless a code of barbarity characteristic of the age; and to which imposture has given it all the consequence which ignorance ascribes to it.
MAHONNE, Fr. a species of galeas or double galley which the Turks use. The Venetian galeasses are larger and stronger built.
MAIDEN, an edged instrument used at Edinburgh in former times for the decapitation of criminals. The original invention is by some attributed to an inhabitant of Halifax, in Yorkshire. The guillotine, so called from a French physician of that name, and by which the unfortunate Louis the Sixteenth was executed, January 21st, 1793, owes its origin to the Maiden.
MAIL, primarily denotes the holes or meshes in a net: it likewise signifies a round iron ring. Hence
Coat of Mail, a coat of armor or steel net-work, anciently worn for defence.
MAILLET, Fr. a mallet. The French formerly made use of this instrument as an offensive weapon in their engagements.
In 1351 the mallet was used at the famous battle des Trente (of thirty) which derived its name from the number of combatants that fought on each side.
This extraordinary combat, holds a distinguished place in the history of Britanny, and was entered into by the partisans of Charles of Blois, and the king of France on one side, and by the count Montfort and the king of England on the other.