How high in (mmH2O) is the column of water in the tube? A long glass tube, sealed at one end, has an inner diameter of 23.4 mm. The tube is filled with water and inverted into a pail of water. If the atmospheric pressure is 735 mmHg, how high (in mmH2O) is the column of water in the tube (d of Hg = 13.5 g/mL; d of H2O = 1.00 g/mL)? 


This problem really confuses me, I know I have to use the ratio of heights of the liquid columns is inversely related to the ratio of the densities of the liquids:
hH20/hHg = dHg/dH2O. I just can't seem to put it together. I would appreciate any help on this problem.
Consider the air pressure in mm of mercury given. Is water more or less dense? Would an amount of water of the same mass as the mercury in the column take up more or less room?

So what would you need to do to change the 735 mm of mercury to an equivalent mass of water, given the densities cited in the problem?

The diameter of the column is red herring; don't go off on the kipper.