Water Pressure 3

If the open tube is capped and a vacuum pump is used to evacuate all the air from the sealed tube, a vacuum of 0 psia is created within the tube. Because the pressure at any point in a static fluid is dependent upon the height of that point above a reference line, such as sea level, it follows that the pressure within the tube at sea level must still be 14.7 psia. This is equivalent to the pressure at the base of a column of water 33.9 feet high and with the column open at the base, water would rise to fill the column to a depth of 33.9 feet. In other words, the weight of the atmosphere at sea level exactly balances the weight of a column of water 33.9 feet in height.

The weight of the atmosphere at sea level is the same and as the weight of column of water 33.9 feet at sea level.