Exaust valve to Eyebolt.

Exhaust valve. The valve of an en­gine which provides an outlet for the gas or steam which has con­tributed its power to the operation of the engine.
Ex libris. (Prillt.) An expression com­monly used on book plates. From the Latin, meaning, from the books of.
Exogenous. (Bot.) Applied to those plants which increase in size by successive concentric rings beneath the bark and outside the previous growth.
Exotic Cuel. (Aerosp.) Unorthodox fuel combinations for aircraft and rocket use to attain greater thrust.
Expanded. That which is increased in size without increasing the sub­stance. (Print.) Name given to a type face whose width is slightly greater than a normal one.
Expanded metal. Sheet metal so stamped or cut that it may be stretched to form a network to re­inforce concrete or retain plaster.
Ex-panding mandrel. (Mach.) A form of lathe mandrel or arbor which is made to expand within the work. .
Expansion. (Phys.) Spreading out, enlarging, increasing in size.
Expansion bit. (Woodwk.) A boring bit having a cutter or cutters ar­ranged to permit radial adjustment. to enable one tool to bore holes of different diameters.
Expansion bolt. A bolt equipped with a split casing which acts as a wedge; used for attaching to brick or con­crete.
Expansion fit. (Metalwk.) For a tight fit of metal parts one within another, the inner part is con­tracted by dry ice of freezing and placed in position. Opposite the shrink fit.
Expansion joint. (Engin.) A device for overcoming the motion of ex­pansion and contraction in pipes. In steam and hot-water heating sys­tems, the expansion joints in risers are of the (a) sliding sleeve type or (b) "sylphon"bellows type. The lat­ter are preferable on low-pressure systems up to 15 pounds pressure. (Masonry) Bituminous filler strip
used to separate blocks or units of concrete to allow for expansion.
Expansion reamer. (Mach.) A reamer which admits of a limited amount of adjustment for size. Such adjustment is usually through wedge action controlled by a screw.
Experiment. A test or trial for the purpose of determining results un­der known conditions.
Experiment (or test) chamber. (Aero.) The central porition of a wind tunnel, where aircraft mod­els or other objects are tested.
Explosive. That which is liable to explode or to violently burst forth from within by force.
Exponent. (Math.)A small number or symbol .placed above and to the right or-a mathematical quantity, to indicate the number of times the quantity is to be taken as a factor. Thus a4 means a'a'a'a.
Exposure. (Photog.) Total amount

Exposure meter. (Photog,) A device showing the amount of light present for a correct exposure of the photographic film.
Extended type. (Prillt.) Type of extra width, even wider than expanded type. A general term used to de­scribe any extra-wide type.
Extending. Carrying out farther than the original point or limit.
Ext~nsion bit. (Elec., Wood.) A bit with an extra long shank to permit the drilling of deep holes or where obstructions would make impossi­ble the use of regular bit.
Extension cord. (Elec.) A length of cable or lamp cord fitted with a plug and socket for the purpose of bring­ing light or power closer to the point where it is needed.
Extension tap. (Mach.) A tap with an extra .long shank to permit tapping in places difficult to reach as for set screws in the hub of a pulley.
Extensometer. A micrometer by which is measured the expansion of a body. (Ellgill.) A device used in the test­ing of metals.
Exterior. (Bldg. alld Mas.ollry) The outside of, as a whole or in part, as the exterior of a building; an exte­rior wall.
Exterior finish, iJaint, etc. A type of finish suited to outside work.
External aileron. (Aero.) A separate airfoil mounted clear of the wing surfaces of an airplane but usually attached to them and deflected for lateral control.

External circuit. (Elec.) That part of an electric circuit which is out­side the source of current.
External drag wire. (Aero.) A drag wire run from a wing to the fuse­lage or other part of the airplane.
External thread. (Mach.) The thread on the outside of a screw, or bolt.
Extra condensed. (Prillt.) Relates to a type face much thinner than av­erage; i.e., the letter is narrow with regard to its height.
Extrados. (Arch.) The outside curve of an arch.
Extra heavy. (Plumb.) When applied to pipe, indicates pipe thicker than standard pipe. Extraneous. Not essential; foreign. Extrusion. (Plast.) The more or less continuous forcing of plastic, re­duced from the granulated resin compound by heat and-pressure to a fluid, through a shaped ori­fice into a finished product such as tube, sheet, rods, and packag­ing stock.
Extrusion molding. (Plast.) A molding procedure for extended shapes of uniform cross section, whereby a heat-softened sub­stance is forced through a die having an orifice shaped likek the cross section of the article.
Extrusion of metal. (Meta/wk.) This is a process by which hot of cold metal is forced under high pres­sure through an opening to pro­duce a desired shape.
Eyebolt. (Mech.) A bolt provided with a hole or eye at one end, instead of the usual head. The eye receives a pin, stud, or hook, which takes the pull of the bolt.