Angle to Anhydrous ammonia.

Andiron to Angle of lead
acoustically "dead" room without reverberation or any characteristic sound of its own is said 0 be anechoic.
Andiron. A metal support for wood in an open fireplace. Sometimes called a "firedogty". .
Anemometer. An instrument for meas­ uring the velocity of an air current.
Aneroid altimeter. (Aero.) An alti­meter, the indications of which de­pend on the deflection of a pres­sure-sensitiv~ element. The gradu­ations of the 'dial correspond to an empirical or arbitrary pressure-tem­perature-altitude formula.
Aneroid barometer. Shows the pres­sure of the atmosphere by the move­ments of the elastic top or dia- . phragm of an exhausted metallic box. Indicates weather changes and height above sea level.
Angle. (Math.) The difference in direction of two straight lines; the space between two straight lines that do or would meet. Angles are
used for. measuring circular movement or rotation.
Angle bead. (Arch.) A molded strip used in an angle; usually where two walls meet at right angles.
Angle bracket. (Arch.) A form of sup­port having two faces generally at right angles to each other. A web is often added to increase strength.
Angie dividers. (Woodwk.) A tool for bisecting angles; also can be used as a try square.
Angle iron. (Mech.) A strip of struc­tural iron, the section of which is in the form of a right angle.
Angle of attack. (Aero.) The acute angle between the chord of an airfoil and its direction of motion relative to the air.
Angle of deadrise. (Aero.) The an­gle with the horizontal made by a
transverse joining the keel of a . hull with the chine.
Angle of declination. (Elec.) The angle of variation. The angle bet­ ween the geographic meridian of a place and the magnetic meridian.
Angle of deviation. The angle equal to the difference between .the an­gle of incidence and the angle of refraction of a ray of light passing through the surface between one medium and another of different refractive index.
Angle of dip. (Elec.) The angle which a magnetic needle makes with the horizon when the verti­cal plane in which it turns corre­ sponds with the magnetic merid­ian.
Angle of heel. (Aero.) 1he angle between a horizontal plane and the lateral axis of a seaplane on the water.
Angle of incidence. (Aero.) Same as angle of wing setting.
Angle of inclination. (Mach.) The angle formed by a screw thread with relation to its axis.
Angle of lag. (Eke.) The angle which shows the amount by which the phase of the active component falls behind the total current in the alternating current circuit.
Angle of lead. (Elec.) The angle
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through which commutator brushes are moved out of the normal plane to avoid sparking.
Angle of pitch. (Aero.) The acute angle between two pl~nes, defined as follows: One plane includes the lateral axis of the aircraft and the direction of the relative wind; the other plane includes the lateral axis and the longitudinal axis. In nor­mal flight the angle of pitch is the angle between the longitudinal axis and the direction of the relative wind.
Angle of reflection. The angle that a ray of light reflected from a sur­face makes with a normal to the surface at the point reflection.
Angle of refraction. The angle bet­ween a refracted ray and a line drawn normal to the interface bet­
ween two media at the point of ' refraction.
Angle of repose, or angle of friction. (Mech.) The angle of a plane surface, inclined relatively to the horizon, upon which a body will, under specific conditions, just begin to slide. It varies with the
nature of the particular materials placed in contact.
Angle of roll. (Aero.) The acute angle through which an aircraft must by rotated about its longitudinal axis in order to bring its lateral axis into a horizontal plane. Also called "angle of bank."
Angle of stabilizer seting. (Aero.) The acute angle between the line of thrust of an airplane and the chord of the stabilizer.
Angle 'of thread. (Mach.) The angle included between the sides of the thread measured in an axial plane.
Angle of View. That portion of a scene visible through a particular lens; usually expressed as the hori­zontal width of a scene as viewed by a lens; determined by focal length of the lens.
Angle of wing setting. (Aero.) The acute angle between the plane of the wing chord and the line of thrust. It may differ for each wing.
Angle of yaw. (Aero.) The acute angle between the direction of the relative wind and the plane of symmetry of an aircraft. It is posi­tive when the aircraft has turned to the right.
Angle plate. (Mach.) Used in set­ting up work, generally for ma­chinery; made of cast irqn, being formed of two plates of metal at right angles with each other, and pierced with holes or slots for the reception of bolts.
Angular cutter. (Mach.) A milling cutter on which the cutting face is at an angle with regard to the axis of the cutter.
Angular gears. (Mach.) Bevel gears
designed to run at angles other than a right angle. '
Angular velocity. (Mech.) The ratio which the arc described in one sec­ond" by a body or point rotating about a center, bears to the radius.
Anhydride. (Chern.) The product left when water is removed from a compound. H2S04-H20 = SO3
Anhydrous. (Chern.) Destitute of water; dried up; withered.
Anhydrous ammonia. (Chern.) Puri­fied ammonia gas liquefied by cold and pressure. Used for organic
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