Source : Webster's Revised Unabridged Dictionary (1913)

Ascertain \As`cer*tain"\, v. t. [imp. & p. p. {Ascertained}; p.
   pr. & vb. n. {Ascertaining}.] [OF. acertener; a (L. ad) +
   certain. See {Certain}.]
   1. To render (a person) certain; to cause to feel certain; to
      make confident; to assure; to apprise. [Obs.]

            When the blessed Virgin was so ascertained. --Jer.
                                                  Taylor.

            Muncer assured them that the design was approved of
            by Heaven, and that the Almighty had in a dream
            ascertained him of its effects.       --Robertson.

   2. To make (a thing) certain to the mind; to free from
      obscurity, doubt, or change; to make sure of; to fix; to
      determine. [Archaic]

            The divine law . . . ascertaineth the truth.
                                                  --Hooker.

            The very deferring [of his execution] shall increase
            and ascertain the condemnation.       --Jer. Taylor.

            The ministry, in order to ascertain a majority . . .
            persuaded the queen to create twelve new peers.
                                                  --Smollett.

            The mildness and precision of their laws ascertained
            the rule and measure of taxation.     --Gibbon.

   3. To find out or learn for a certainty, by trial,
      examination, or experiment; to get to know; as, to
      ascertain the weight of a commodity, or the purity of a
      metal.

            He was there only for the purpose of ascertaining
            whether a descent on England was practicable.
                                                  --Macaulay.