TYMPAN, (Tympan, Fr.) In architecture, the area of a pediment, being that part which is on a level with the naked part of the frize. Or it is the space included between the three cornices of a triangular pediment, or the two cornices of a circular one.
Tympan of an arch, is the triangular space or table in the corners or sides of the arch, usually hollowed and enriched, sometimes with branches of laurel, olive-tree, or oak, or with trophies, &c. Sometimes with flying figures, as fame, victory, &c. or sitting figures, as the cardinal virtues.
TYMPANUM. A drum, a musical instrument which the ancients used, and which consisted of a thin piece of leather or skin, stretched upon a circle of wood or iron, and beat with the hand. Hence the origin of our drum.
Tympanum. In mechanics, a kind of wheel placed round an axis or cylindrical beam, on the top of which are two levers, or fixed staves, for the more easy turning the axis about, in order to raise a weight required. It is also used for any hollow wheel, wherein one or more persons or animals, such as horses, dogs, &c. walk to turn it. This wheel is found in cranes, calenders, &c.
V.
VACANCY, (vacance, Fr.) State of an office or commission to which no one is appointed.
VACANT, (Vacant, e. Fr.) Empty; not filled.
Vacant Companies, (Compagnies vacantes, Fr.) Companies to the permanent command of which no person is appointed.
Emplois-Vacans, Fr. During the French monarchy, seniority of rank or standing did not give the right of promotion. It belonged solely to the king to appoint and nominate all persons to vacant commissions or employments. No other rule can be consistent with the efficiency of a military institution; rotation should be considered only as a contingency, which is only admitted, not permanently established; as no institution so much calls for merit and application to study, as the military profession; merit alone should be the foundation of promotion; then all would endeavor to acquire knowlege; where rotation exists there is no incitement. In the American army, no attention is paid to merit; there is, therefore, very little study.
VACCINE pock, a disease which has been found to affect the cow on the teat or udder, which arises in pustules resembling small pox; it has been found that this is a perfect preventive of small pox and is now growing into use against prejudice among all civilized nations. All armies should undergo the vaccine inoculation, to prevent the ravages of small pox; one half of the American army that went against Quebec in 1775 was swept off by small pox.