Condensation \Con`den*sa"tion\, n. [L. condensatio: cf. F.
   condensation.]
   1. The act or process of condensing or of being condensed;
      the state of being condensed.
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            He [Goldsmith] was a great and perhaps an unequaled
            master of the arts of selection and condensation.
                                                  --Macaulay.
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   2. (Physics) The act or process of reducing, by depression of
      temperature or increase of pressure, etc., to another and
      denser form, as gas to the condition of a liquid or steam
      to water.
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   3. (Chem.) A rearrangement or concentration of the different
      constituents of one or more substances into a distinct and
      definite compound of greater complexity and molecular
      weight, often resulting in an increase of density, as the
      condensation of oxygen into ozone, or of acetone into
      mesitylene.
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   Condensation product (Chem.), a substance obtained by the
      polymerization of one substance, or by the union of two or
      more, with or without separation of some unimportant side
      products.

   Surface condensation, the system of condensing steam by
      contact with cold metallic surfaces, in distinction from
      condensation by the injection of cold water.
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Surface \Sur"face`\, n. [F. See Sur-, and Face, and cf.
   Superficial.]
   1. The exterior part of anything that has length and breadth;
      one of the limits that bound a solid, esp. the upper face;
      superficies; the outside; as, the surface of the earth;
      the surface of a diamond; the surface of the body.
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            The bright surface of this ethereous mold. --Milton.
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   2. Hence, outward or external appearance.
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            Vain and weak understandings, which penetrate no
            deeper than the surface.              --V. Knox.
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   3. (Geom.) A magnitude that has length and breadth without
      thickness; superficies; as, a plane surface; a spherical
      surface.
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   4. (Fort.) That part of the side which is terminated by the
      flank prolonged, and the angle of the nearest bastion.
      --Stocqueler.
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   Caustic surface, Heating surface, etc. See under
      Caustic, Heating, etc.

   Surface condensation, Surface condenser. See under
      Condensation, and Condenser.

   Surface gauge (Mach.), an instrument consisting of a
      standard having a flat base and carrying an adjustable
      pointer, for gauging the evenness of a surface or its
      height, or for marking a line parallel with a surface.

   Surface grub (Zool.), the larva of the great yellow
      underwing moth (Triphoena pronuba). It is often
      destructive to the roots of grasses and other plants.

   Surface plate (Mach.), a plate having an accurately dressed
      flat surface, used as a standard of flatness by which to
      test other surfaces.

   Surface printing, printing from a surface in relief, as
      from type, in distinction from plate printing, in which
      the ink is contained in engraved lines.
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