t from which the measurements are made in
determining the pitch.

Pivoted. A bar, lever, or other mechanical element, arranged to
turn on or about a point.

Plastic. A substance in such a state that it may be kneaded or
worked.

Planer. A large tool designed to cut or face off wood or metal.

Porosity. The quality in all substances to have interstices,
or points of separation, between the molecules.

Potential. The power.

Properties. The qualities possessed by all elements.

Projecting. The throwing forward. The sending out.

Promulgated. Put forth; enunciated.

Protractor. A mechanic's and draughtsman's tool by means of
which angles may be formed.

Promote. To carry forward in a systematic way.

Precision. Work done with care; observing correct measurements.

Prony brake. A machine for determining horse power.

Punch. A small tool to be struck by a hammer in order to
make an impression or indentation.

Quadrant. One-fourth of a circle.

Quadrant plate. A plate on which are placed lines and numbers
indicating degrees.

Quadruplex. A term to designate that system of telegraphy in
which four messages are sent over a single wire at
the same time.

Ratchet. A wheel having teeth at certain intervals to catch
the end of a pawl or finger.

Ratchet brace. A tool to hold a drill, having a reversible ratchet
wheel.

Rasp cut. A cut of a file which is rough, not smooth.

Rake. The angle or inclination of the upper surface of the
cutting tool of a lathe.

Reverse. To turn about; in the opposite direction.

Reciprocating. To go back and forth.

Revolve. To move in an orbit or circle, as a merry-go-round.

Reciprocity. To give back in like measure.

Reflection. The throwing back from a surface.

Resonance. The quality of vibration which adds to the original
movement, and aids in perpetuating the sound.

Refraction. The quality of light which causes it to bend in passing
through different substances.

Reducing. Bringing it down to a smaller compass.

Rectilinear. A straight line.

Retort.