Coaxial speaker to Cold rolling.

Coaxial speaker. A loud-speaker consisting of a bass cone with a concentrically mounted. tweeter.
Cobalt. (Min.) A tough, pink-white metal of the iron group. Valuable for the blue pigments it forms.
Cobaltcrom steel. (Engin.) An alloy steel containing 1.5 percent carbon, 12.5 per cent chromium, and 3.5 per cent cobalt. Suitable for cutting tools.
Cock. (Plumb.) A plug type of valve which has on opening to permit passage ofliquids or gases. A quar­ter turn opens or closes the valve.
Cock beading. (Furn.) A small, semi­circular, projecting molding, used around drawers.
Cockle. (Bookbndg.) The condition of papers in books when too much dampness is allowed to permeate through the book; also applied to covers when raising, pulling, wav­ing, warping, or ~urling exists. (Finish) An irregular but intention­ally produced fInish.
Cockling. (Papermkg. and Print.)
. Wavy edges on paper caused by irregular drying. (Textile) An irregular shrinking on the surface of a fabric.
Cockpit. (Aero.) The open spaces in an airplane provided with seating accommdations for pilot and pas­sengers. When entirely housed in, it is clled a "cabin".
Cockpit cowling. (Aero.) A metal or plywood cowling placed around a cockpit.
Cocoboio. (Wood) Dalbergia. A central American tree of the rosewood family. The wood is reddish in colour with bands of black; very hard and oily. Used for bowling balls and knife handles.
Coconut oil. (Chern.) Obtained from the fruit of the coconut palm. Used in the manufacture of hard-water soaps.
Code. Any set of roles devised for the purpose of securing uniformity in work and for the maintaining of prope~ standards is usaully called a code; e.g., a building code.
Code beacon. (Aero.) A flashing bea­con light having a recognizable char­acteristic of dots and I or dashes by which its individual identity can be established.
Coefficient. (Math.) A prefixed number to be used as a multiplier. (phys.) A number indicating the de­gree (\f a qulaity of a substance or material.
Coefficient of expansion. (Engin.) The factor which expresses the change per unit length of any material for each degree of temperature.
Coefficient of friction. The ratio between the weight of a body and horizontally applied force required to move it over another surface.
Coffer. (Arch.) A deeply recessed panel, in a ceiling or dome.
Cofferdam. A wall of piles between or within which excavating is done for foundations.
Coefficient of restitution. The ratio of the relative velocity of two spheres after direct impact to the before im­pact.
Coefficient of viscosity. The value of

,;Coercive force. The magnetic inten­sity required to reduce the mag­netic induction in a perviously magnetised material to zero.
Cog. (Mech.) An inserted tooth as in a cogwheel. Gears are often impro­perly referred to as cogwheels.
Cogging. (Metal.) Reduction of in­gots to blooms by rolling or forg­mg.
Coherent light. Light in which the electromagnetic waves maintain a fixed phase relationship.
Cohesion. (phys. ) The attraction ex­isting between molecules of the same kind.
Coil. (Elec.) Successive turns of in­sulated wire which create a mag­netic field when an electric current passes through them.
Coinage bronze. (Metal.) An alloy of95 per cent copper, 2~ per cent tin, and 2~ per cent zinc.
Coincidental starter. (Auto. Mech.) A type of started in which the starting-motor switch and the gasoline feed are both controlled by the foot-accelerator pade!.

Coir. The fiber obtained from the outer husk of the coconut, used for brushes, cocoa matting, and rope.
Coke. A fuel made by baking bitumi­nous coal in closed ovens to drive off gases and other elements. A ton of coal produces two-thirds ton of coke. coke is 88 per cent carbon.
Cold. Part of circuit or component 'sit­ting' at a.c. earth o/zero potential. Cold chisel. (Metalwk.) An all-steel . chisel, i.e., without handle, used for the chipping of metals.
Cold drawn. (Metal.) Production of metal into its fmal form by drawing through dies while cold.
Cold flow. (Plast.) Change of dim en­sions or distortion caused by sus­tained application of a force greater than the elastic limit.
Cold molding. (Plast.) A procedure in which a co~position is shaped at ordinary temperatures and hardened by subsequent baking.
Cold molding coinpounds. (Plast.) Those molding powders, consisting of a filler and binder are formed into a mass under pressure in a die at room temperature and later heated in ovens to harden.
Cold-rolled steel. (Metal.) May be either of open-hearth or Bessemer process. The carbon content runs from 0.12 to 0.20 percent. This steel is marketed with a bright, smooth surface and is made quite accurate to size so that for many purposes no machining is necessary. It may be casehardened but will not temper.
Cold rolling. Cold rolling of steel pro­duces a high tensile strength but with