=Radial.= Extending out from the center.
=Radiation.= The property of many substances to give forth heat or cold, or to disperse it.
=Rarified.= Made less than the normal pressure, as air, which is not as dense at a high as at a low altitude.
=Receiver.= In telephone apparatus, that part of the mechanism which transmits the message to the ear.
=Rectilinear.= A right line; a straight direction forwardly.
=Reaction.= A force which is counter to a movement in another direction.
=Refrigeration.= Cooling process; the art of freezing.
=Refined.= Purifying; improved.
=Re-heating.= The process of further heating or increasing the temperature during the progress of the work.
=Requisite.= The necessary part; the requirement.
=Residue.= The balance; what is left over.
=Resistance.= Opposition; against.
=Reciprocating.= One for the other; moving from one side to the other.
=Refinement.= Chastity of thought, taste, manner, or actions.
=Retort.= A vigorous answer. A receptacle adapted to stand a high heat.
=Revolution.= Turning, like the earth in its orbit.
=Rock Shaft.= A shaft which turns part of its rotation in one direction, and then turns in the other direction.
=Rotation.= The turning of a wheel on its axle; the rotation of the earth on its axis each day. Distinguishing from revolution which is a swinging of the entire body of the earth around the sun in its orbit.
=Sal-Ammoniac.= A white metallic element.
=Scavenging.= To clean out; to scour.
=Secondary A battery which is charged with a Battery.= current, and then gives forth an electric current of a definite amount.
It is also known as an _accumulator_, since its elements continue to accumulate electric energy.
=Secondary coil.= In induction coils two wire wrappings are necessary, the first winding being, usually, of heavy wire, and called the primary; the second winding is of finer wire, and is called the secondary coil.
=Sector.= An A-shaped piece cut from a disk; distinguish this from a segment, which is a part cut off from a disk by a single straight line.
=Secondary.= Occupying a second place; not of the first kind, or place.
=Segment.= A part cut off from a disk, by a single line; the part of a circle included within a chord and its arc.
=Sewerage.= The conveyance of waste matter from a building.
=Sinuous.= Systematic draining by means of pipes or conduits. Characterized by bends, or curves, or a serpentine curving, or wave-like outline.
=Slide Valve.= A form, which moves along a flat surface through which the duct is formed.
=Solution.= A liquid having therein different substances mixed together.
=Sprayer.= To eject; to send forth in small particles.
=Stability.= Fixed; strength to stand without support.
=Stupendous.= Immense; large; much beyond the largest of the kind.
=Standard.= A sample of the measure or extent; a type or a model.
=Stratify.= To deposit, form, or range in strata.
=Super Heating.= To heat up beyond the ordinary or normal point.
=Subtle.= Crafty; made of light material; daintily constructed.
=Supersede.= In place of; to take the place of.
=Susceptible.= Capable of being changed or influenced.
=Suspension.= Hanging; floating of a body in fluid.
=Suction.= The production of a partial vacuum in a space connected with a fluid under pressure.
=Terminal.= The end; the last part.
=Technical.= Specially or exclusively pertaining to some art or subject.
=Theoretical.= That which is speculative, as distinguished from practical.
=Throttle Valve.= A device which is designed to cut off the flow of a fluid.
=Throttling.= The closing of a port; the cutting down of a supply.
=Transformation.= A complete change; made over into something else.
=Transmit.= To convey; to send to another part.
=Transference.= To convey to another part; the change from one thing to another.