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 made by the angle, for one complete turn, the distance traveled by the propeller axially indicates the pitch in feet.
Placement. When an object is located at any particular point, so that it is operative the location is called the placement.
Plane. A flat surface for supporting a flying machine in the air. Plane of movement pertains to the imaginary surface described by a moving body. A bicycle wheel, for instance, when moving forwardly in a straight line, has a plane of movement which is vertical; but when the machine turns in a circle the upper end of the wheel is turned inwardly, and the plane of rhovement is at an angle.
Pliant. Easily yielding; capable of being bent; liable to be put out of shape.
Plurality. See multiplicity. More than one.
Poise. Held in suspension; disposed in a particular way.
Pontoon. Applied to a series of boats ranged side by side to support a walk laid thereon. In aviation it has reference to a float for supporting an aeroplane.
Ponderous. Large; heavy; difficult to handle.
Posterior. The rear end; the opposite of anterior.
Principles. The very nature or essence of a thing; the source or cause from which a thing springs.
Proportion. The relation that exists between different parts or things.
Propounded. Questioned; stated; to state formally for consideration
Proprietary. A right; the ownership of certain property.
Primitive. The beginning or early times; long ago.
Prelude. A statement or action which precedes the main feature to be presented.
Proximity. Close to; near at hand.
Prototype. That which is used as the sample from, which something is made or judged.
Propeller. The piece of meebanism, with screw shaped blade, designed to be rapidly rotated in order to drive a vessel forwardly. It is claimed by some that the word Impeller would be the more proper term.
Primarily. At the first; the commencement.
Precedes. Goes ahead; forward of all.
Propulsive. The force which gives motion to an object.
Projected. Thrown forward; caused to fly through the air.
Radially. Out from the center; projecting like the spokes of a wheel.
Ratio. The relation of degree, number, amount; one with another.
Reaction. A counterforce; acting against.
Recognize. To know; seeing, hearing, or feeling, and having knowledge therefrom.
Reflection. Considering; judging one thing by the examination of another. A beam of light, or an object, leaving a surface.
Refraction. That peculiarity in a beam of light, which, in passing through water at an angle, bends out of its course and again assumes a direct line after passing through.
Reflex. Turned back on itself, or in the direction from which it came.
Requisite. Enough; suffieient for all purposes.
Relegate. To put back or away.
Rectangular. Having one or more right angles.
Reservations. Land which is held by the Government for various purposes.
Resistance. That which holds back; preventing movement.
Retarding. Preventing a free movement.
Revoluble. The turning or swinging motion of a body like the earth in its movement around the sun. See Rotative. To cause to move as in an orbit or circle.
Resilient. Springy; having the quality of elasticity.
Reversed. Changed about; turned front side to the rear.
Rotative. That which turns, like a shaft. The movement of the earth on its axis is rotative.
Saturation. Putting one substance into another until it will hold no more. For instance, adding salt to water until the water cannot take up any more.
Security. Safety, assuredness that there will be no danger.
Segment. A part eut off from a circle. Distinguished from a sector, which might be likened to the form of one of the sections of an orange.
Sexagonal. Six-sided.
Sine of the Angle. The line dropped from the highest point of anangle to the line which runs out horizontally.
Sinuous. Wavelike; moving up and down like the waves of the ocean.
Simulates. To pattern or copy after; the making of the like.
Skipper. A thin flat stone.
Spirally-formed. Made like an auger; twisted.
Stability. In airships that quality which holds the ship on an even and unswerving course, and prevents plunging and side motions.
Structural. Belonging to the features of eonstruetion.
Strata. Two or more layers; one over or below the other.
Stream line. In expressing the action of moving air, or an aeroplane transported through air, every part is acted upon by the air. Stream lines are imaginary lines which act upon the planes at all points, and all in the same direction, or angle.
Stupendous. Great; important; above the ordinary.
Substitute. One taken for another; replacing one thing by something else.
Supporting. Giving aid; helping another.
Synchronous. Acting at the same time, and to the same extent. Thus if two wheels, separated from each other at great distances, are so arranged that they turn at exactly the same speed, they are said to turn synchronously.
Tactics. The art of handling troops in the presence of an enemy. It differs from strategy in the particular that the latter word is used to explain the movements or arrangement of forces before they arrive at the battle line.
Tandem. One before the other; one after the other.
Tangent. A line drawn from a circle at an angle, instead of radially.
Technically. Pertaining to some particular trade, science or art.
Tenuous. Thin, slender, willowy, slight.
Tetrahedral. This has reference to a form which is made up of a multiplicity of triangularly shaped thin blades, so as to form numerous cells, and thus make a large number of supporting surfaces. Used as a kite.
Theories. Views based upon certain consideration.
Theoretical. Where opinions are founded on certain information, and expressed, not from the standpoint of actual knowledge, but upon conclusions derived from such examinations.
Torsion. A twist; a circular motion around a body.
Transmitted. Sent out; conveyed from one point to another.
Transformed. Changed; entirely made over from one thing to another.
Transverse. When a body is shorter from front to rear than from side to side its longest dimension is transversely. Distinguish from lateral, which has reference only to the distance at right angles from the main body.
Translation. The transportation of a body through the air.
Trajectory. The path made by a body projected through the air.
Triangular. A form or body having three sides and three angles.
Typical. In the form of; a likeness to.
Ultimate. The end; the finality; the last that can be said.
Uninitiated. Not having full knowledge; withont information.
Unique. Peculiar; something that on account of its peculiar construction or arrangements stands out beyond the others.
Universal. Everywhere; all over the world.
Undulate. To move up and down; a wave-like motion.
Utility. Of use; to take advantageous use of.
Unstable. Not having anything permanent; in a ship in flight one that will not ride on an even keel, and is liable to pitch about.
Vacuum. Where air is partly taken away, or rendered rarer.
Valved. A surface which has a multiplicity of openings with valves therein, or, through which air can move in one direction.
Vaunted. To boast concerning; to give a high opinion.
Velocity. Speed; the rate at which an object can move from place to place.
Vertical. A line running directly to the center of the earth; a line at right angles to the surface of water.
Vibratory. Moving from side to side; a regular motion.
Volplane. The glide of a machine without the use of power.
Warping. The twist given to certain portions of planes, so as to cause the air to aet against the warped portions.
Weight. The measure of the force which gravity exerts on all objects.