3. Atmospheric pressure is often given in units of millimeters of mercury. This refers to the height of a mercury column above the mercury's surface at the base of a barometer . The force exerted by the atmosphere on the surface of the mercury in the reservoir equals the weight of the mercury in the column . If the mercury column extends 760 mm above the mercury's surface in the reservoir , what is the atmosphere's pressure over the mercury ? Use 13.6*10^ 3 kg/m^ 3 for the density of mercury