资料来源 : pyDict

长臂圆规

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Beam \Beam\, n. [AS. be['a]m beam, post, tree, ray of light;
   akin to OFries. b[=a]m tree, OS. b?m, D. boom, OHG. boum,
   poum, G. baum, Icel. ba?mr, Goth. bahms and Gr. ? a growth, ?
   to become, to be. Cf. L. radius staff, rod, spoke of a wheel,
   beam or ray, and G. strahl arrow, spoke of a wheel, ray or
   beam, flash of lightning. ?97. See {Be}; cf. {Boom} a spar.]
   1. Any large piece of timber or iron long in proportion to
      its thickness, and prepared for use.

   2. One of the principal horizontal timbers of a building or
      ship.

            The beams of a vessel are strong pieces of timber
            stretching across from side to side to support the
            decks.                                --Totten.

   3. The width of a vessel; as, one vessel is said to have more
      beam than another.

   4. The bar of a balance, from the ends of which the scales
      are suspended.

            The doubtful beam long nods from side to side.
                                                  --Pope.

   5. The principal stem or horn of a stag or other deer, which
      bears the antlers, or branches.

   6. The pole of a carriage. [Poetic] --Dryden.

   7. A cylinder of wood, making part of a loom, on which
      weavers wind the warp before weaving; also, the cylinder
      on which the cloth is rolled, as it is woven; one being
      called the fore beam, the other the back beam.

   8. The straight part or shank of an anchor.

   9. The main part of a plow, to which the handles and colter
      are secured, and to the end of which are attached the oxen
      or horses that draw it.

   10. (Steam Engine) A heavy iron lever having an oscillating
       motion on a central axis, one end of which is connected
       with the piston rod from which it receives motion, and
       the other with the crank of the wheel shaft; -- called
       also {working beam} or {walking beam}.

   11. A ray or collection of parallel rays emitted from the sun
       or other luminous body; as, a beam of light, or of heat.

             How far that little candle throws his beams !
                                                  --Shak.

   12. Fig.: A ray; a gleam; as, a beam of comfort.

             Mercy with her genial beam.          --Keble.

   13. One of the long feathers in the wing of a hawk; -- called
       also {beam feather}.

   {Abaft the beam} (Naut.), in an arc of the horizon between a
      line that crosses the ship at right angles, or in the
      direction of her beams, and that point of the compass
      toward which her stern is directed.

   {Beam center} (Mach.), the fulcrum or pin on which the
      working beam of an engine vibrates.

   {Beam compass}, an instrument consisting of a rod or beam,
      having sliding sockets that carry steel or pencil points;
      -- used for drawing or describing large circles.

   {Beam engine}, a steam engine having a working beam to
      transmit power, in distinction from one which has its
      piston rod attached directly to the crank of the wheel
      shaft.

   {Before the beam} (Naut.), in an arc of the horizon included
      between a line that crosses the ship at right angles and
      that point of the compass toward which the ship steers.

   {On the beam}, in a line with the beams, or at right angled
      with the keel.

   {On the weather beam}, on the side of a ship which faces the
      wind.

   {To be on her beam ends}, to incline, as a vessel, so much on
      one side that her beams approach a vertical position.



   4. Extent; reach; sweep; capacity; sphere; as, the compass of
      his eye; the compass of imagination.

            The compass of his argument.          --Wordsworth.

   5. Moderate bounds, limits of truth; moderation; due limits;
      -- used with within.

            In two hundred years before (I speak within
            compass), no such commission had been executed.
                                                  --Sir J.
                                                  Davies.

   6. (Mus.) The range of notes, or tones, within the capacity
      of a voice or instrument.

            You would sound me from my lowest note to the top of
            my compass.                           --Shak.

   7. An instrument for determining directions upon the earth's
      surface by means of a magnetized bar or needle turning
      freely upon a pivot and pointing in a northerly and
      southerly direction.

            He that first discovered the use of the compass did
            more for the supplying and increase of useful
            commodities than those who built workhouses.
                                                  --Locke.

   8. A pair of compasses. [R.] See {Compasses.}.

            To fix one foot of their compass wherever they
            please.                               --Swift.

   9. A circle; a continent. [Obs.]

            The tryne compas [the threefold world containing
            earth, sea, and heaven. --Skeat.]     --Chaucer.

   {Azimuth compass}. See under {Azimuth}.

   {Beam compass}. See under {Beam}.

   {Compass card}, the circular card attached to the needles of
      a mariner's compass, on which are marked the thirty-two
      points or rhumbs.

   {Compass dial}, a small pocket compass fitted with a sundial
      to tell the hour of the day.

   {Compass plane} (Carp.), a plane, convex in the direction of
      its length on the under side, for smoothing the concave
      faces of curved woodwork.

   {Compass plant}, {Compass flower} (Bot.), a plant of the
      American prairies ({Silphium laciniatum}), not unlike a
      small sunflower; rosinweed. Its lower and root leaves are
      vertical, and on the prairies are disposed to present
      their edges north and south.

            Its leaves are turned to the north as true as the
            magnet: This is the compass flower.   --Longefellow.

   {Compass saw}, a saw with a narrow blade, which will cut in a
      curve; -- called also {fret saw} and {keyhole saw}.

   {Compass timber} (Shipbuilding), curved or crooked timber.

   {Compass window} (Arch.), a circular bay window or oriel
      window.

   {Mariner's compass}, a kind of compass used in navigation. It
      has two or more magnetic needles permanently attached to a
      card, which moves freely upon a pivot, and is read with
      reference to a mark on the box representing the ship's
      head. The card is divided into thirty-two points, called
      also rhumbs, and the glass-covered box or bowl containing
      it is suspended in gimbals within the binnacle, in order
      to preserve its horizontal position.

   {Surveyor's compass}, an instrument used in surveying for
      measuring horizontal angles. See {Circumferentor}.

   {Variation compass}, a compass of delicate construction, used
      in observations on the variations of the needle.

   {To fetch a compass}, to make a circuit.