The Collaborative International Dictionary of English v.0.48:

Acoustic \A*cous"tic\ (#; 277), a. [F. acoustique, Gr. ?
   relating to hearing, fr. ? to hear.]
   Pertaining to the sense of hearing, the organs of hearing, or
   the science of sounds; auditory.
   [1913 Webster]

   Acoustic duct, the auditory duct, or external passage of
      the ear.

   Acoustic telegraph, a telegraph making audible signals; a
      telephone.

   Acoustic vessels, brazen tubes or vessels, shaped like a
      bell, used in ancient theaters to propel the voices of the
      actors, so as to render them audible to a great distance.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Telegraph \Tel"e*graph\, n. [Gr. ? far, far off (cf. Lith. toli)
   + -graph: cf. F. t['e]l['e]graphe. See Graphic.]
   An apparatus, or a process, for communicating intelligence
   rapidly between distant points, especially by means of
   preconcerted visible or audible signals representing words or
   ideas, or by means of words and signs, transmitted by
   electrical action.
   [1913 Webster]

   Note: The instruments used are classed as indicator,
         type-printing, symbol-printing, or chemical-printing
         telegraphs, according as the intelligence is given by
         the movements of a pointer or indicator, as in Cooke &
         Wheatstone's (the form commonly used in England), or by
         impressing, on a fillet of paper, letters from types,
         as in House's and Hughe's, or dots and marks from a
         sharp point moved by a magnet, as in Morse's, or
         symbols produced by electro-chemical action, as in
         Bain's. In the offices in the United States the
         recording instrument is now little used, the receiving
         operator reading by ear the combinations of long and
         short intervals of sound produced by the armature of an
         electro-magnet as it is put in motion by the opening
         and breaking of the circuit, which motion, in
         registering instruments, traces upon a ribbon of paper
         the lines and dots used to represent the letters of the
         alphabet. See Illustration in Appendix, and Morse
         code.
         [1913 Webster]

   Note: In 1837, Samuel F. B. Morse, an American artist,
         devised a working electric telegraph, based on a rough
         knowledge of electrical circuits, electromagnetic
         induction coils, and a scheme to encode alphabetic
         letters. He and his collaborators and backers
         campaigned for years before persuading the federal
         government to fund a demonstration. Finally, on May 24,
         1844, they sent the first official long-distance
         telegraphic message in Morse code, "What hath God
         wrought," through a copper wire strung between
         Washington, D.C., to Baltimore, Maryland. The phrase
         was taken from the Bible, Numbers 23:23. It had been
         suggested to Morse by Annie Ellworth, the young
         daughter of a friend. --Library of Congress, American
         Memories series
         (http://memory.loc.gov/ammem/today/may24.html).
         [PJC]

   Acoustic telegraph. See under Acoustic.

   Dial telegraph, a telegraph in which letters of the
      alphabet and numbers or other symbols are placed upon the
      border of a circular dial plate at each station, the
      apparatus being so arranged that the needle or index of
      the dial at the receiving station accurately copies the
      movements of that at the sending station.

   Electric telegraph, or Electro-magnetic telegraph, a
      telegraph in which an operator at one station causes words
      or signs to be made at another by means of a current of
      electricity, generated by a battery and transmitted over
      an intervening wire.

   Facsimile telegraph. See under Facsimile.

   Indicator telegraph. See under Indicator.

   Pan-telegraph, an electric telegraph by means of which a
      drawing or writing, as an autographic message, may be
      exactly reproduced at a distant station.

   Printing telegraph, an electric telegraph which
      automatically prints the message as it is received at a
      distant station, in letters, not signs.

   Signal telegraph, a telegraph in which preconcerted
      signals, made by a machine, or otherwise, at one station,
      are seen or heard and interpreted at another; a semaphore.


   Submarine telegraph cable, a telegraph cable laid under
      water to connect stations separated by a body of water.

   Telegraph cable, a telegraphic cable consisting of several
      conducting wires, inclosed by an insulating and protecting
      material, so as to bring the wires into compact compass
      for use on poles, or to form a strong cable impervious to
      water, to be laid under ground, as in a town or city, or
      under water, as in the ocean.
      [1913 Webster]