Asphaltum varnish to Attraction.

Asphaltum varnish to Atom

sources are Trinidad and Venezuela. "Gilsonite" is the name applied to that asphaltum, similar in appear­ance to coal, which is mined in Utah.
Asphaltum varnish. The best quality is known as "gilsonite"-black in colour and comparatively expen­sive. It is used where quick drying is essential giving an effect similar to a Japan finish. Common asphaltum varnish used principaIly for its heat and acid-resisting quali­ties, is black in colour if used on an absorbent surface such as wood, but appears slightly brownish on a metal surface. The largest users are battery manufacturers.
Assay. To analyze ores for the pur­pose of determining the amount of precious metal contained therein.
Assemble. (Shopwk.) To coIlect or put in place the parts of a machine or other manufactured article.
Assembled car. (Auto.) One for which a car manufacturer buys engines, axles, steering gear, body, and per­haps other items from individual parts manufacturers, and completes the assembly in his own plant.
Assembling. The putting together in correct relation of the parts which comprise a piece of mechanism.
Assembly line. A method of
progressive assembly introduced early in automobile manufacture but applied to many lines of production. Usually, the line is kept in continuous motion, workers adding parts to the mechanism as it passes by.
Assets. Money or convertible property such as could be made avafIable for payment of debts, etc.
Assume. Take for granted.

A stage resins. (Plast.) Thermoset­ting. resins react only to the initial stage wh~re they are soluble and fusible. The normal stage of a resin used for impregnation.
Astatic galvanometer. (Elec.) A very senstive galvanometer which neu­tralizes the effect of the earth's magnetism by the use of astatic needles.
Astragal. (Arch.) A smaIl semicircu­lar molding, either plain or ornamented, frequently used to cover the joint between doors.
Astigmatism. An aberration of a lens or optical system that causes lines in some directions to be focused less sharply than lines in other directions.
Astrogation. (Aerosp.) Navigation in space.
Astronaut. One who travels through space. Also caIled cosmonaut.
Asymmetric. Not idenitcal on both sides of a tentral line; lacking symmerty.
Asymptote. (Math.) A straight line which continuaIly approaches a curve without touching it.
Atmospheric pressure. (Phys.) The pressure extended due to the weight of the air above the earth. At sea level this pressure is about
14.7 pounds per square inch. The atmospheric pressure. of 14.7 pounds wiIl support or balance a column of mercury 29.92 in. high.
Atom. An atom may be considered the smaIlest particle of an element that takes part in a chemical change. It has a nucleus of one or more positive charges bf electric­ity called "protons." Revolving

-Atomic energy to Attraction
around its protons are charges of negative electricity called "elec­trons." The atom is electrically neutral.
Atomic energy. See Nuclear energy. Atomic hydrogen welding. An alter­nating-current arc-welding process wherein heat is obtained from an arc between two electrodes in an
atmosphere of hydrogen.
Atomic number. (Chern.) The number of planetary electrons in an atom.
Atoniic theory. (Chem~) The theory which asserts that all substances are composed of infinitesimally small particles .or atoms.
Atomic weight. (Chem.) The weight of the atom of any element as com­pared with another as a standard; usually hydrogen is taken as l.
Atomize. To divide a stream or jet of any liquid into a fine spray resem­. bling smoke or dust in appearance.
Atomizer. A device for breaking a liquid into fine particles.
Atrium. (Arch.) A large hall or lobby with galleries on three or more sides at each floor level.
Attachment. (Mach.) Any device used in connection with a machine in order to give a wider range or better quality or work.
Attachment plug. (Elec.) A small plug fastened to the end of flex­ible cord and attachable to socket or baseboard to carry current to any appliance.
Attenute. To reduce the level of an electrical signal, usually with a volume or loudness control. Also, to reduce sound levels acousti­cally through the use of absorp­tion mateirals.
Attenuator. A pot which is used to reduce the gain of an incoking sig­nal. Commonly found on interface units which have to span the gulf between two industry code stan­dards.
Attic. (Arch.) In modern structures, that space between the roof and the ceiling of the upper story. In classical structures, that part which extends above the level of the cornice.
Attitude. (Aero.) The position of an aircraft as determined by the in­clination of its axes to some frame of reference, usually the horizon.
Attitude indicator. (Aero.) A gyro­scopic instrument which shows the pilot the position of his airplane with reference to the earth's hori­zon. Also called flight indicator.
Attraction. (Elec.) Pull or force act­ing between two unlike (N and S) magnetic poles; or between two unlike (+ and -) static charges.