Torricellian tube

Torricellian tube

(ˌtɒrɪˈsɛlɪən)
n
(General Physics) a vertical glass tube partly evacuated and partly filled with mercury, the height of which is used as a measure of atmospheric pressure
[C17: named after E. Torricelli]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014