The physical properties of-fresh water are well known and are stated in engineers’ handbooks and in textbooks on hydraulics. One can readily find, for example, that pure water at ordinary air temperatures weighs about 62.4 pounds per cubic foot and that fresh river water weighs about 62.5. Usually there is added a table giving the weight for various temperatures.
When we consult the handbooks and hydraulic texts for similar information concerning sea water, however, we usually find nothing at all or else the bare statement that it weighs 64 pounds per cubic foot. Even the English and American books on oceanography say almost nothing about the weight of sea water.