BLINDS are sometimes only canvas stretched to obstruct the sight of the enemy. Sometimes they are planks set up, for which see MANTLET. Sometimes they are made of a kind of coarse basket-work; see GABIONS. Sometimes of barrels, or sacks filled with earth. In short, they signify any thing that covers the labourers from the enemy. BLIND See ORILLON and FORTIFICATION. BLOCKADE, BLOCKADING, in military affairs, implies the surrounding a place with different bodies of troops, who shut up all the avenues on every side, and prevent every thing from going in or out of the place; this is usually effected by means of the cavalry. The design of the blockade is to oblige those who are shut up in the town, to consume all their provisions, and by that means to compel them to surrender for want of subsistence. Hence it appears that a blockade must last a long time, when a place is well provided with necessaries; for which reason this method of reducing a town is seldom taken, but when there is reason to believe the magazines are unprovided, or sometimes when the nature or situation of the place permits not the approaches to be made, which are necessary to attack it in the usual way. Maritime towns, which have a port, are in much the same case as other towns, when their port can be blocked up, and the besiegers are masters of the sea, and can prevent succours from being conveyed that way into the place. _To_ BLOCKADE, or to block up a place, is to shut up all the avenues, so that it cannot receive any relief either of men or provisions, &c. _To raise a_ BLOCKADE, is to march from before a place, and leave it free and open as before. _To turn a siege into a_ BLOCKADE, is to desist from a regular method of besieging, and to surround the place with those troops who had formed the siege. _To form a_ BLOCKADE, is to surround the place with troops, and hinder any thing from going in or coming out. A new species of BLOCKADE has been discovered during the French Revolution, a blockade by _proclamation_. BLOCUS, _Fr._ See _Blockade_. BLOCK _battery_, in gunnery, a wooden battery for two or more small pieces, mounted on wheels, and moveable from place to place: very ready to fire _en barbet_, in the galleries and casemates, &c. where room is wanted. BLOCK-_house_, in the military art, a kind of wooden fort or fortification, sometimes mounted on rollers, or on a flat-bottomed vessel, serving either on the lakes or rivers, or in counter-scarps and counter-approaches. This name is sometimes given to a brick or stone building on a bridge, or the brink of a river, serving not only for its defence, but for the command of the river, both above and below. BLUNDERBUSS, a well known fire-arm, consisting of a wide, short, but very large bore, capable of holding a number of musquet or pistol balls, very fit for doing great execution in a croud, making good a narrow passage, defending the door of a house, stair-case, &c. or repelling an attempt to board a ship.