Escallonia, a genus of saxifragaceous shrubs and trees, natives chiefly of the Andes. E. rubra is a handsome evergreen shrub, with shiny, resinous, aromatic leaves, and fine pink flowers; it is hardy in many parts of Britain, and makes an excellent hedge, especially near the sea, where it bears the salt-laden winds without damage.
1, Dead-beat or repose escapement. The pallets are concentric with the axis a, and thus while a tooth is against the pallet the wheel is stationary.
2, Recoil escapement. The pallets are not concentric to the axis a, and therefore a slight recoil of the wheel takes place after the escape of a tooth (whence the name escapement). When the pallets leave a tooth, the teeth slide along their surfaces, giving an impulse to the pendulum. Lettering for 1 and 2: The anchor H L K is made to oscillate on the axis a by the pendulum. The teeth of the escapement-wheel A come alternately against the outer surface of the pallet K and the inner surface of the pallet H.
3, Chronometer escapement. As the balance rotates in the direction of the arrow, the tooth V presses the spring against the lever, thus pressing aside the lever and removing the detent from the tooth of the wheel. As the balance returns, V presses aside and passes the spring without moving the lever, which then rests against the stop E.
Escape´ment, the general contrivance in a timepiece by which the pressure of the wheels (which move always in one direction) and the vibratory motion of the pendulum or
balance-wheel are accommodated the one to the other. By this contrivance the wheelwork is made to communicate an impulse to the regulating power (which in a clock is the pendulum and in a watch the balance-wheel), so as to restore to it the small portion of force which it loses in every vibration, in consequence of friction and the resistance of the air. The leading requisite of a good escapement is that the impulse communicated to the pendulum or balance-wheel shall be invariable, notwithstanding any irregularity or foulness in the train of wheels. Various kinds of escapements have been contrived, some of which are shown in the accompanying figure. See Clock; Watch.
Es´car, or Esker, a geological formation in the superficial drift, generally consisting of a long linear ridge of sand and gravel, sometimes including blocks of considerable size. The materials are derived from the waste of till or boulder-clay, and their arrangement took place probably in water flowing in channels beneath ice-sheets, the escar becoming exposed as the ice finally melted away. In Sweden escars have been formed, season by season, at the mouths of glacier-tunnels as the ice shrank back, the ice-front opening on a lake. See Kames.
Eschar (es´ka˙r), a slough or portion of dead or disorganized tissue. The name is commonly applied to the crust or scab occasioned on the skin by burns or caustic applications.
Eschatol´ogy (es-ka-; Gr. eschatos, last, and logia, account), in theology, the 'doctrine respecting the last things', which treats of the millennium, the second advent of Christ, the resurrection, judgment, conflagration of the world, and the final state of the dead.