Manometer
Device used to measure the pressure in gaz or liquids. In chemistry, lab manometer are mainly used for measuring gas pressure.
U tube manometer
This is the simplest form of pressure measuring device. It consists of a "U" tube partially filled with a liquid, usually mercury.
One end is connected to the container being studied and another end which is open to air or vacuum. In the second case, the pressure is measured as the difference Dh in height between the liquid levels in the two arms of the tube.
