“One of the most important properties of water is its ability to dissolve a very large number of solids and gases without chemically reacting with them. As a consequence all the water on the earth is more or less impure, that is, it contains in addition to chemically linked hydrogen and oxygen (H20), a number of other substances in varying amounts Sea-water, according to Defant, is a dilute solution of a mixture of salts.
By weight, 3.5 percent of the ocean is solid matter. Of this matter, the most common substance is sodium chloride or common table salt. Other elements found as salts in the ocean are magnesium, sulfur, calcium, potassium and bromine.
Some of the atmospheric gases are also present in sea-water in dissolved form. It may be interesting to note that some elements, such as chlorine, bromine, boron, and sulfur, are found in greater quantities in the oceans than on land.