Automatic. A thing which operates by its own mechanism; a contrivance which is made in such a manner that it will run without manual operation or care. Alertness. Quick; being active. Apex. The point at which two lines meet; also the extreme pointed end of a conical figure. Ascension. Moving upwardly. Accessories. The parts of a machine, or artielee which may ha used in connection therewith. Anemometer. An instrument for measuring the force or the velocity of wind. Anemograph. An instrument that usually traces a curved line OH paper to make a record of the force or direction, or velocity of the wind. Anemometrograph. A device which determines the force, velocity and direction of the wind. Accretion. Adding to little by little. Accelerated. Quiekening; hurrying the process. Abridged. Partly taken away from; shortened. Abrogate. To dispense with; to set aside. Abnormal Not in the usual manner; not in a regular way. Alternate. First one and then another; going from one side to the other. Ancient Lights. An old English law which prevents a neighbor from shutting off sunlight. Angularly. A line which runs out from another so that the two are not parallel. Aneroid. Not wet. Applied to the type of barometer where the medium for determ,ining the pressure is not made of mercury. Aspirate. A term given by the French to that peculiar action of wing, or other body, which, when placed in certain positions, relative to a current of air, will cause it to be drawn into the current. Assemblage. The bringing together of the parts or elements of a machine. Augment. To aid; to add to or increase. Banked. The term used in aviation which indicates that the machine is turned up so that its supporting surfaces rest against the air, as in alighting. Barometer. An instrument for determining the air pressure, and thereby indicating altitudes. Bevel Pinion. A toothed wheel driven by a larger wheel. Bi-Plane. Two planes. In aviation that type which has two planes, similar in size, usually, and generally placed one above the other so they are separated the same distance from each other, as the width of each of the planes. Bulge. A hump; an enlargement beyond the normal at any point. Camber, also Cambre. The upward curve in a plane. Catapult. A piece of mechanism for projecting or throwing a missile. Carbureter. The device which breaks up the fuel oil, and mixes the proper quantity of air with it before it is drawn into the engine. Catastrophe. A calamity; a sad ending; loss of life or of property. Cellular. Made up of small hollows, or compartments; filled with holes. Celestial. Pertaining to the heavens. Centrifugal. That force which throws outwardly from a rotating body. Centripetal. That force, like the attraction of gravity, which draws a body to the center. Characteristic. Striking; that which is peculiar to some thing or object. Commensurate. Sufficient; in proper proportion; sufficient for the occasion.