Baffle colour to Ball race.

Bad colour. (Print.) The appearance caused on the printed sheet by ink, too much or too little used.
Bad copy. (Print.) Manuscript which
cannot be e<l?ily read.
Badger. (Art.) An artist's brush made of badger's hair. (Carp.) A wide rabbet plane having a skew mouth.
Baffle plate. A diaphragm or thin plate used to deflect or retard the flow of gases.

Bagasse. (Plast.) Fibrous by-product from sugar cane. It is much used as a building board.
Bag molding. (Plast.) A commercial method of producing large, three dimensional synthetic resin lami­nations, smooth on both sides. Example: Fiberglass-resin boat molding. A flexible rubber or resin bag is lowered and clamped into the mold, and this is pressed against the rigid mold, either by air pres­sure or by vacuum, forcing the resin up through the glass fiber.
Bail. A haIf hoop or horse shoe-shaped piece for supporting something. Bail ouL (Aero.) To jump from a plane
using a parachute for support.
Bake-IiL (Plast.) A trade name for any of a group of thermosetting plas­tics. It is a synthetic resin used instead of hard rubber or celluloid.
Balance. (Aero.) A condition of steady flight in which the resultant force and moment on the airplane are zero. (Art) A piece of artwork is in balance when its parts are so arranged as to give the most pleasing effect to the eye. (Print.) When type
composition has its various parts so

grouped that they are equalized in mass. (Mech.) A sensitive instru­ment for weighing.
Balanced backflow valve. (Plumb.) A valve with a counter-balanced gate.
Balanced circuit. (Elec.) An electri­cal circuit so adjusted with respect to near-by circuits as to escape the influence of mutual induction. A three-wire circuit having the same Iload on each side of the neutral wire.
Balanced core. (Fdry.) A core which is supported only at one end.
Balanced pulley. A pulley which has been weighted and tested for bal­ance, at rest and in motion, to pre­vent excessive wear on bearings.
Balanced surface. (Aero.) A control surface which extends on both sides of the axis of the pivot in such a manner as to reduce the movement of the air forces about the pivot.
Balanced, dynamic or running. (Shopwk.) Distributing the weight of pulleys or shafts so that, when placed on knife edgeways, they will stand in any position, If unbal­anced, the heavy side rolls to the bottom.
Balance weighL The weight placed on the inner edge of a wheel to effect perfect balance. A weight slid over the end of a lever and attached thereto to counterbalance a moving part.
Balance wheel. A flywheel. Its purpose is to insure smooth and re.gular motions in an engine or machine.
Balancing machine. A machine which measures the "out of balance" of a revolving piece and indicates amount and location of the neces­sary correction.
Balancing way. (Shopwk.) Level strip or sharP-edge disk for testing shafts or pulleys for standing balanc.e. the disks are usually mounted on ball bearings.
Balcony.' A platform or gallery pro­jecting from the wall of a building, enclosed by a balustrade or parapet.
Balk. (Cmp.) A squared beam ortimber. Balk ring. (Auto. Mech.) A friction
regulated pawl or plunger used to facilitate the engagement of gears.
Ball and claw foot. (Furn.) A carved foot representing a ball grasped by a claw.
Ballast. Gravel or broken stone for a railroad bed.
Ball bearing. (Auto. Mech.) Anyone of the various bearings consisting of hardened steel balls in some sort of retainer, so constructed that load is carried by the balls.
Ball check valve. The active part of such a valve consists of a ball rest­ing on a seat. Under pressure, the ball rises from the seat and permits flow in one direction; when pres­sure is removed or reversed, the ball returns to its closed position.
Ball clay. (pot.) The lump of claywhich a potter places in the center of his revolving table and from which he forms pottery shapes.
BaIl cock. (Plumb.) A faucet opened or closed by the fall or rise of a ball on the surface of the water.
Balling. (Metal.) Forming wrought iron into balls in the furnace, pre­paratory to their passage through the squeezer.
Ballistics. The science of the charac­teristics and behaviour of projec­tiles shot from firearms or artillery, or of bombs dropped from aircraft.
Ball mill. (Ceram.) A cylindrical grinding mill for pulverizing or mixing dry material, usually por­celain. Often a lined drum which uses flint pebbles as the grinding element. Also called pebble mill.
Ballonet. (Aero.) A compartment, constructed as a unit or partitioned off, inside a balloon or airship, to maintain gas pressure by blowing
in or letting out air.
Balloon. (Aero.) An aerostat without a propelling system.
Balloon framing. (Bldg.) Studs ex­tended in one piece from the foun­dation to the roof; the joists, in
addition to being supported by a ledger board, are nailed to the studs.
Balloon tire. (Auto. Mech.) A rela­tively large, flexible, thin-walled tire designed for low air pressures. The flexible wall and low pressure provide "easy-riding" qualities
Ballpeen bammer. (Metalwk.) The type of hammer commonly used by machinists; one end of the head is rounded or ball shaped for
riveting or peening; the surface of the other end is flat and is used for striking a chisel, or in other such work.
Ball race. (Mach.) In a ball bearing,