Torr i cell i an exper'iment

(tor-re-chel'I-an) [Evangelist a Torr i cell i, Italian physicist, 1608-1647.] A gla tube sealed at one end is filled with mercury and is then everted with the open end beneath the surface of mercury in an open ve el; the mercury in the tube will be observed to sink to a certain point, about 30 inches above the level of the mercury in the ve el, being kept at this elevation by the pre ure of the atmosphere; this experiment revealed the principle of the mercurial barometer. T. vac'uum, the vacuum at the upper end of the barometer tube resulting from the sinking of the column of mercury to the point where it is balanced by the atmospheric pre ure.