130
ion, it would be an abnormal pressure.
Notoriously. Generally known, but not favorably so; the subject of general remark; or unfavorably known.
Obscurity. Not well known; in the background; without clear vision; hidden from view.
Obliquely. That which differs from a right angle; neither obtuse nor acute; deviating from a line by any angle except a right angle.
Obvious. That which is readily observed and understood.
Orthopter. That type of flying machine which depends on flapping wings to hold it in space, and to transport it, in imitation of the motion of the wings of birds in flying.
Oscillate. Moving to and fro; the piston of a steam engine has an oscillating motion.
Outline. Describing a marginal line on a drawing; setting forth the principal features of an argument, or the details of a story, or the like.
Overlapping. One placed over the other.
Parabolic. A form of curve somewhat similar to an ellipse.
Pedestal. A standard or support; an upright to hold machinery.
Pertinent. Appropriate; pertaining to the subject.
Pectoral. The bone which forms the main rib or support at the forward edge of a bird's wing.
Persistent. Keeping at it; determination to proceed.
Perpendicular. At right angles to a surface. This term is sometimes wrongly applied in referring to an object, particularly to an object which is vertical, meaning up and down. The blade of a square is perpendieular to the handle at all times, but the blade is vertical only when it points to the center of the earth.
Pernicious. Bad; not having good features or possessing wrong attributes.
Pendulum. A bar or body suspended at a point and adapted to swing to and fro.
Perpetual. For all time; unending or unlimited time.
Phenomena. Some peculiar happening, or event, or object.
Pitch. In aviation this applies to the angle at which the blades of a propeller are cut. If a propeller is turned, and it moves forwardly in the exact path
