torricellian

from The Century Dictionary.

• Pertaining to Evangelista Torricelli, an Italian physicist and mathematician (1608–47), who, in 1643, discovered the principle on which the barometer is constructed, by means of an experiment called from him the Torricellian experiment.

from the GNU version of the Collaborative International Dictionary of English.

• adjective 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.
• adjective 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.
• adjective (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.