If the atmospheric pressure is 755 mmHg, explain how high (inmmH2O) is the column of water in the tube (d of Hg =13.5 g/mL; d of H2O = 1.00 g/mL)? A long glass tube, sealed at one end, has an inner diameter of 10.0mm. The test tube is filled with water and inverted into a pail of water.