Source : Webster's Revised Unabridged Dictionary (1913)

   3. A bicycle or a tricycle; a velocipede.

   4. A rolling or revolving body; anything of a circular form;
      a disk; an orb. --Milton.

   5. A turn revolution; rotation; compass.

            According to the common vicissitude and wheel of
            things, the proud and the insolent, after long
            trampling upon others, come at length to be trampled
            upon themselves.                      --South.

            [He] throws his steep flight in many an a["e]ry
            wheel.                                --Milton.

   {A wheel within a wheel}, or {Wheels within wheels}, a
      complication of circumstances, motives, etc.

   {Balance wheel}. See in the Vocab.

   {Bevel wheel}, {Brake wheel}, {Cam wheel}, {Fifth wheel},
   {Overshot wheel}, {Spinning wheel}, etc. See under {Bevel},
      {Brake}, etc.

   {Core wheel}. (Mach.)
      (a) A mortise gear.
      (b) A wheel having a rim perforated to receive wooden
          cogs; the skeleton of a mortise gear.

   {Measuring wheel}, an odometer, or perambulator.

   {Wheel and axle} (Mech.), one of the elementary machines or
      mechanical powers, consisting of a wheel fixed to an axle,
      and used for raising great weights, by applying the power
      to the circumference of the wheel, and attaching the
      weight, by a rope or chain, to that of the axle. Called
      also {axis in peritrochio}, and {perpetual lever}, -- the
      principle of equilibrium involved being the same as in the
      lever, while its action is continuous. See {Mechanical
      powers}, under {Mechanical}.

   {Wheel animal}, or {Wheel animalcule} (Zo["o]l.), any one of
      numerous species of rotifers having a ciliated disk at the
      anterior end.

   {Wheel barometer}. (Physics) See under {Barometer}.

   {Wheel boat}, a boat with wheels, to be used either on water
      or upon inclined planes or railways.

   {Wheel bug} (Zo["o]l.), a large North American hemipterous
      insect ({Prionidus cristatus}) which sucks the blood of
      other insects. So named from the curious shape of the
      prothorax.

   {Wheel carriage}, a carriage moving on wheels.

   {Wheel chains}, or {Wheel ropes} (Naut.), the chains or ropes
      connecting the wheel and rudder.

   {Wheel cutter}, a machine for shaping the cogs of gear
      wheels; a gear cutter.

   {Wheel horse}, one of the horses nearest to the wheels, as
      opposed to a leader, or forward horse; -- called also
      {wheeler}.

   {Wheel lathe}, a lathe for turning railway-car wheels.

   {Wheel lock}.
      (a) A letter lock. See under {Letter}.
      (b) A kind of gunlock in which sparks were struck from a
          flint, or piece of iron pyrites, by a revolving wheel.
      (c) A kind of brake a carriage.

   {Wheel ore} (Min.), a variety of bournonite so named from the
      shape of its twin crystals. See {Bournonite}.

   {Wheel pit} (Steam Engine), a pit in the ground, in which the
      lower part of the fly wheel runs.

   {Wheel plow}, or {Wheel plough}, a plow having one or two
      wheels attached, to render it more steady, and to regulate
      the depth of the furrow.

   {Wheel press}, a press by which railway-car wheels are forced
      on, or off, their axles.

   {Wheel race}, the place in which a water wheel is set.

   {Wheel rope} (Naut.), a tiller rope. See under {Tiller}.

   {Wheel stitch} (Needlework), a stitch resembling a spider's
      web, worked into the material, and not over an open space.
      --Caulfeild & S. (Dict. of Needlework).

   {Wheel tree} (Bot.), a tree ({Aspidosperma excelsum}) of
      Guiana, which has a trunk so curiously fluted that a
      transverse section resembles the hub and spokes of a
      coarsely made wheel. See {Paddlewood}.

   {Wheel urchin} (Zo["o]l.), any sea urchin of the genus
      {Rotula} having a round, flat shell.

   {Wheel window} (Arch.), a circular window having radiating
      mullions arranged like the spokes of a wheel. Cf. {Rose
      window}, under {Rose}.

Barometer \Ba*rom"e*ter\, n. [Gr. ? weight + -meter: cf. F.
   barom[`e]tre.]
   An instrument for determining the weight or pressure of the
   atmosphere, and hence for judging of the probable changes of
   weather, or for ascertaining the height of any ascent.

   Note: The barometer was invented by Torricelli at Florence
         about 1643. It is made in its simplest form by filling
         a graduated glass tube about 34 inches long with
         mercury and inverting it in a cup containing mercury.
         The column of mercury in the tube descends until
         balanced by the weight of the atmosphere, and its rise
         or fall under varying conditions is a measure of the
         change in the atmospheric pressure. At the sea level
         its ordinary height is about 30 inches (760
         millimeters). See {Sympiesometer}. --Nichol.

   {Aneroid barometer}. See {Aneroid barometer}, under
      {Aneroid}.

   {Marine barometer}, a barometer with tube contracted at
      bottom to prevent rapid oscillations of the mercury, and
      suspended in gimbals from an arm or support on shipboard.
      

   {Mountain barometer}, a portable mercurial barometer with
      tripod support, and long scale, for measuring heights.

   {Siphon barometer}, a barometer having a tube bent like a
      hook with the longer leg closed at the top. The height of
      the mercury in the longer leg shows the pressure of the
      atmosphere.

   {Wheel barometer}, a barometer with recurved tube, and a
      float, from which a cord passes over a pulley and moves an
      index.