Torrs
Abbreviation/Symbol:
Torr
Definition:
1 torr is defined as 1/760 of an atmosphere, or 101325/760 Pascals
Origin:
The Torr is named after Evangelista Torricelli who invented the mercury barometer. The torr was originally defined as being equal to one millimetre of mercury. Because the height of mercury is dependant on temperature and gravity, the Torr was redefined in 1954 as being 1/760 of an atmosphere.