Source : Webster's Revised Unabridged Dictionary (1913)

Torricellian \Tor`ri*cel"li*an\, a.
   Of or pertaining to Torricelli, an Italian philosopher and
   mathematician, who, in 1643, discovered that the rise of a
   liquid in a tube, as in the barometer, is due to atmospheric
   pressure. See {Barometer}.

   {Torricellian tube}, a glass tube thirty or more inches in
      length, open at the lower end and hermetically sealed at
      the upper, such as is used in the barometer.

   {Torricellian vacuum} (Physics), a vacuum produced by filling
      with a fluid, as mercury, a tube hermetically closed at
      one end, and, after immersing the other end in a vessel of
      the same fluid, allowing the inclosed fluid to descend
      till it is counterbalanced by the pressure of the
      atmosphere, as in the barometer. --Hutton.



   {Vacuum valve}, a safety valve opening inward to admit air to
      a vessel in which the pressure is less than that of the
      atmosphere, in order to prevent collapse.

   {Torricellian vacuum}. See under {Torricellian}.