CHEVRETTE, a kind of gin. Among the many inventions for raising guns or mortars into their carriages this engine is very useful; it is made of two pieces of wood about four feet long, standing upright upon a third, which is square: they are about a foot asunder, and parallel; pierced with holes opposite one another, to hold a strong bolt of iron, which may be raised higher or lower at pleasure: it may be used with a hand-spike, which takes its poise over this bolt, to raise any thing by force. CHEVROTINES, _Fr._ leaden bullets of small calibre; there are generally sixty to a pound weight. CHIEF _or_ CHIEFTAIN, the head leader, or commander of any clan in time of war, was so called, especially among the Scotch. CHIORME, _Fr._ the crew of galley slaves and bonavogliers or volunteers. CIMIER, _Fr._ a heavy ornament, which the ancient knights or chevaliers in France and in other countries were accustomed to wear upon their helmets; small figures were afterwards substituted in their stead. CHOROGRAPHY, in _engineering_, is the art of making a drawing or map of a country, province or district. CIMETAR, See SCIMITAR. CINQUAIN, in _ancient military history_, was an order of battle, to draw up 5 battalions, so that they might make 3 lines; that is, a van, main-body, and reserve. Supposing the 5 battalions, to be in a line, the 2d and 4th advance and form the van, the 3d falls back and forms the rear, the 1st and 5th form the main body upon the same ground. Lastly, every battalion ought to have a squadron of horse on both the right and left wings. Any number of regiments, produced by multiplying by 5, may be drawn up in the same manner. CIRCLE, in _mathematics_, is a plane figure, comprehended under one line only, to which all right lines drawn from a point in the middle of it are equal to one another. CIRCUMFERENTER, an instrument used by engineers for measuring angles. CIRCUMVALLATION, or _line of circumvallation_, in _military affairs_, implies a fortification of earth, consisting of a parapet and trench, made round the town intended to be besieged, when any molestation is apprehended from parties of the enemy, which may march to relieve the place. Before the attack of a place is begun, care is to be taken to have the most exact plan of it possible; and upon this the line of circumvallation and the attack are projected. This line, being a fortification opposed to an enemy that may come from the open country to relieve the besieged, ought to have its defence directed against them; that is, so as to fire from the town: and the besiegers are to be encamped behind this line, and between it and the place. The camp should be as much as possible out of the reach of the shot of the place; and the line of circumvallation, which is to be farther distant from the place than the camp, ought still more to be out of the reach of its artillery.