Description

The fortin type barometer consists of a long glass tube sealed at one end and filled with mercury. The tube is inverted so that the open end is submerged in a cistern of mercury. . The height of the mercury in a tube is a mercury of the atmospheric pressure acting on the mercury in the cistern. Reading are taken by first adding the mercury level in the cistern to a zero point and then moving a vernier to the top of the mercury column