ENVELOPE, in fortification, a work of earth, sometimes in form of a single parapet, and at others like a small rampart: it is raised sometimes in the ditch, and sometimes beyond it. Envelopes are sometimes _en zic-zac_, to inclose a weak ground, where that is practicable, with single lines, to save the great charge of horn works, crown works, and tenailles, or where room is wanting for such large works. These sort of works are to be seen at Besancon, Douay, Luxembourg, &c. Envelopes in a ditch are sometimes called sillons, contregardes, conserves, lunettes, &c. which words see. _To_ ENVIRON, to surround in a hostile manner, to hem in, to besiege. EPAULE, in fortification, denotes the shoulder of a bastion, or the place where its face and flank meet, and form the angle, called the angle of the shoulder. See FORTIFICATION. EPAULEMENT, in fortification, is a kind of breast work to cover the troops in front, and sometimes in flank. In a siege, the besiegers generally raise an epaulement of 8 or 10 feet high, near the entrance of the approaches, to cover the cavalry, which is placed there to support the guard of the trenches. These works are sometimes made of filled gabions, or fascines and earth. This term is frequently used for any work thrown up to defend the flank or a post, or any other place. It is sometimes taken for a demi-bastion, and at other times for a square orillon to cover the cannon of a casemate. See FORTIFICATION. EPAULETTES, are shoulder knots, worn by officers; those for the officers are made of gold or silver lace, with rich fringe and bullions, those of non-commissioned are of cotton or worsted. They are badges of distinction worn on one or both shoulders. When a serjeant or corporal is publicly reduced, the shoulder-knot is cut off by the drum major in the front or circle of the battalion. Among the French, all the degrees of rank, from a cadet to a general officer, were so minutely marked out by the epaulette, that a common centinel might instantly know what officer approached his station, and could pay the prescribed honors without hesitation or mistake. All officers above the rank of captain wear two in the United States army and militia; captains wear one on the right shoulder: lieutenants and ensigns on the left; serjeants and corporals wear as captains and lieutenants. Epaulettes have been introduced into the British navy. The following are the gradations of rank as distinguished by epaulettes. Masters and commanders have one epaulette on the left shoulder. Post captains under three years, one epaulette on the right shoulder. And after having been post three years, two epaulettes. Rear admirals have one star on the strap of the epaulette, vice admirals two stars, and admirals three stars. EPEE, _Fr._ a sword. EPERON, _Fr._ a spur. EPICYCLOID, a curve formed by the revolution of the periphery of a circle along the convex or concave part of another circle.