CHEMIN _des rondes_, in _fortification_, space between the rampart and low parapet under it, for the rounds to go about it. CHEMISE, _Fr._ an obsolete term to signify the revetement made of brick work, which was formerly constructed to secure works made of earth, especially those that were formed of sandy soil, and would necessarily require too large a talus to support the weight. The modern term is _ouvrage revetu_, _place revetüe_. CHEMISE _de feu_, _Fr._ a French sea-term, to signify several pieces of old sails of various sizes, which after they have been pitched, and thoroughly soaked in other combustible matter, such as oil of petrol, camphor, &c. may be nailed to an enemy’s ship on boarding her, and when set fire to, will consume the same. CHEMISE _de maille_, _Fr._ a shirt of mail, or body lining made of several scales or iron rings, which was worn under the coat to protect the body of a man. CHEMISTRY, the art of examining bodies, and of extracting from them any of their component parts; a science of the first importance to military men; it opens to the mind so many sources of knowlege applicable to military uses. CHESS, a nice and abstruse game, supposed to have been invented during the siege of Troy. This game is particularly adapted to military capacities. CHEVAL _de Bois_, _Fr._ a wooden-horse, a military chastisement, which prostitutes who followed the French army, were subject to undergo, by exposing them, we presume, on a wooden-horse. CHEVALER, in the manege, is said of a horse, when, in passing upon a walk or trot, his off fore leg crosses the near fore leg every second motion. CHEVALET, _Fr._ a sort of bell-tent, formerly used in the French service, when an army encamped. It resembled in some degrees the wigwam of the Indian. CHEVALIER, in a _general sense_, signifies a knight or horseman. CHEVAUX-_de frize_, in _fortification_, a large joist or piece of timber, about 5 or 6 inches square, and 10 or 12 feet in length; into the sides whereof are driven a great number of wooden pins, about 6 feet long, and 1¹⁄₂ inch diameter, crossing one another at right angles, and pointed with iron. They are used on numberless occasions, as to stop up breaches, to secure avenues to a camp from the inroads both of horse and foot. They are sometimes mounted on wheels, with artificial fires, to roll down in an assault, &c. They were first used at the siege of Groningen, in 1658. CHEVAUX-_de-frize_. The _body_ or _beam_ of a cheval-de-frize is generally made 9 feet long, and 6 inches square, and weighs 41 lbs. The _spears_ are 33 in number, weighing 2 lb. each, are 5 feet long, and 1¹⁄₄ inches square. They are placed 9¹⁄₂ inches asunder. CHEVET, _Fr._ a small wedge which is used in raising a mortar, it is placed between the frame and swell of the mortar. CHEVISANCE, _Fr._ enterprize, feat, or atchievement. CHEVRE, _Fr._ a crab or gin. See CHEVRETTE.