Crossover frequency to Crystallization.

Crossover frequency. In loud­speaker systems and multi-ampli­fier audio installations, the border­line frequencies between low/me­dium range and medium/high range speakers or amplifiers.
Cross network. A unit which divides the audio spectrum into two or more frequency bands. (See"crossover frequency")low level

crossover network. A crossover network designed to op­erate at line levels and which is placed. before the power ampli­ fier (s); used in bi-or triamplified speaker systems. May be an elec­tronic crossover.high level
cross over network. A crossover net­work designed to operate at high levels and which is placed between the power amplifier and the loud­speakers (the type of crossover nor­
mally built into a speaker system). ..
Cross network, electronic. A line level (low level) crossover network which has built-in preamplifiers to avoid signal losses and/or to feed long audio cables. (See "crossover network, low level")
Crossover network, passive. A crossover network vv hich does not include amplifiers; may be low level or high level. .
Crossover point. See "crossover frequency".
Cross unit. This is a device used to split a fuIl frequency signal into component frequency bands. This is a technique most favoured by separate amplification system de­
signers. A crossover unit is uaually used to split a signal into three parts; highs mids and lows, each section being sent to the relevant amplifier or loud-speaker.
Cross-peen hammer. (Shopwk.) A hammer with a wedge-shaped peening edge at right angles to the direction of the handle.
Crossrail. (Mach.) That part of a bor­ing mill or planer which supports and
permits movement of to 01 heads and. tool slides.
Cross section. A transverse section at right angles with the longitudinal axis of the work or drawing through which the section is taken.
Cross slide. (Mach.) The horizontal slide or bridge which carries the tool box in a planning machine. The slide which operates on the saddle of a lathe carriage to provide fOT trans­verse feed. It also supports the com­pound rest.
Cross-stitch. (Bookbndg.) A double stitch in the form of a cross.
Cross tap. (Elec.) A joint similiar to a cross joint except that two wires are tapped off the main conductor in­stead of a single wire.
Crosstying springs. ( Uphol.) This sys­tem of tying springs prevents the bUT­lap from sagging into the open spaces between the springs, and adds stability to the uphostering.
Cross valve. ( Mach. ) A valve fitted on a transverse pipe so as to open com­munication at will between two par­allel lines of piping. Much used in oil- and water-pumping arrange­ments.

Cross-wind force. (Aero.) The componenet perpendicular to the lift and to the drag of the total air force on the aircraft or any part thereof.
Crotch veneer. (Furn.) Veneer cut from limb crotch, or from twin trees
which have joined together, form- : ing an unusual ~rain effect
Crowbar. A heavy pinch bar of round iron or steel flattened to a . chisel-like point at one end, used as a lever. .
Crown. A rise in the contour as the center of the face .of a part is ap- , proached, 'as the crown of a road, '
crown of a pulley, etc. (Arch.) The uppermost member of a cornice. (Plumb.) That part of a trap in which the direction of flow is changed from an upward to a downward direction. (Ceram.) The arched roof of a kiln.
Crown back. (Furn.) A feature of the Hogarth chair.
Crown molding. (Arch.) A molding with a double-curv~d face. The up­per member of a closed cornice placed immediately below the roof proper.
Crown pulley. (Mach.) A pulley whose diameter is greater at the middle than at the edges of its face. This crown tends to prevent the belt from ~g off the pulley pro­vided the belt is not slipping.
Crow'$-foot. (Aero.) A system of di­verging short ropes for distributing the load on a single rope.
Crucible. ( Chem.) A vessel generally of refractory material; used for melting purposes.
Crucible steel. A .high-grade steel made by melting wrought iron in a crucible and adding charcoal, pig iron, or some other substance rich in carbon. so that the resulting metal will contain from 0.75 to 1.50 per cent carbon; used for cutlery, tools, dies, etc.
Crude oil. Petroleum in its natural state as it comes from the earth.
Crushing strain. The strain which causes the failure of a material by compression.
Cryolite. (Mineral.) (Na3AIF 6) A snow-white; sodium-aluminium fluoride found mainly in Greenland. It is used in the making of alu­ minium, also in the manufacture of glass.
Crystal diode. (Rad.) Used as a recti­fier, primarily in microwave frequen­cies.
Crystallization. (Chem.) Process of causing a chemical to separate out of either the dissolved or melted state in the form of crystals.