Practical Mechanics for Boys Part 23

Conjunctively. Acting together.

Comparatively. Similitude or resemblance, one with another.

Cotter. A key to prevent a wheel turning on its shaft.

Dead center. A term used to designate the inoperative point of the crank.

Depicting. Showing; setting forth.

Deodorant. A substance which will decompose odors.

Developer. A chemical which will bring out the picture in making the film or plate in photography.

Decimeter. The length of one-tenth of a meter in the metric system.

Decameter. The length of ten meters in the metric system.

Defective. Not perfect; wrong in some particular.

Diaphragm. A plate, such as used in a telephone system, to receive and transmit vibrations.

Dissolving. To change from a solid to a liquid condition.

Division plate. A perforated plate in a gear-cutting machine, to aid in dividing the teeth of a wheel.

Dispelled. To drive away or scatter.

Disinfectant. A material which will destroy harmful germs.

Diametral pitch. The number of teeth in a gear as calculated on the pitch line.

Dimension. Measurement; size.

Ductility. That property of metal which permits it to be drawn out, or worked.

Dividers. An instrument, like a compa.s.s, for stepping off measurements, or making circles.

Diverge. Spreading out from a common point.

Drift. A cutting tool for smoothing a hole in a piece of metal.

Duplex. Two; double.

Dynamite. An explosive composed of an absorbent, like earth, combined with nitro-glycerine.

Dynamometer. An instrument for measuring power developed.

Eccentric. Out of center.

Echoes. The reflection of sound.

Effervesce. The action due to the unity of two opposite chemicals.

Efficiency. The term applied to the quality of effectiveness.

Ellipse. A form which is oblong, or having a shape, more or less, like the longitudinal section of an egg.

Electrolytic. The action of a current of water pa.s.sing through a liquid, and decomposing it, and carrying elements from one electrode to the other.

Elasticity. The quality in certain substances to be drawn out of their normal shape, and by virtue of which they will resume their original form when released.

Embedded. To be placed within a body or substance.

Emerge. To come out of.

Emphasize. To lay particular stress upon.

Emery. A hard substance, usually some of the finely divided precious stones, and used for polis.h.i.+ng and grinding purposes.

Enormous. A large amount; great in size.

Enunciated. Proclaimed; given out.

Equalization. To put on an even basis; to make the same comparatively.

Eradicator. To take out; to cause to disappear.

Escapement. A piece of mechanism devised for the purpose of giving a uniform rate of speed to the movement of wheels.

Essential. The important feature; the princ.i.p.al thing.

Expansion. To enlarge; growing greater.

Equidistant. The same distance from a certain point.

Evolved. Brought out of; the result of certain considerations.

Facet. A face.

Facilitated. Made easy.

Flux. Any substance which will aid in uniting material under heat. The act of uniting.

Fluid. Any substance in which the particles freely interchange positions.

Flour emery. Emery which is finely ground.

Flexible. The quality of any material which will permit bending.