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

A furnace of refractory material to take high heat.

Reamer

A tool designed to enlarge or to smooth out holes.

Regulation

To do things in an orderly way; a system which sets forth certain requirements.

Refractory

Difficult to work, and not easily fused.

Recess

A hole, or a depression.

Rocking

A lever which rotates only part way and then moves in the opposite direction.

Rotate

A spindle which turns round. Compare revolve.

Rosin

Certain gums; particularly the sap of pine trees.

Roughing

The taking off of the first coating with a tool.

Saturated

A soluble substance which cannot be further dissolved by a liquid.

Scribe

To mark with a tool.

Screw plate

A tool which has within it means for adjusting different cutting tools.

Section lining

The marks made diagonally across drawings to indicate that the part is cut away.