=Volume and composition.=—Every 1000 parts of sea-water contain about 34.40 parts by weight of mineral matter in solution. The principal solids, acids, and bases, combined according to the principles laid down by Dittmar, are shown in the following table:[2] Chloride of sodium 77.758 Chloride of magnesium 10.878 Sulphate of magnesium 4.737 Sulphate of calcium 3.600 Sulphate of potassium 2.465 Bromide of magnesium 0.217 Carbonate of calcium 0.345 ------- Total salts 100.000 Expressed in terms of tons per cubic mile of sea-water, the composition is as follows:[139] Tons per Cubic Mile. Chloride of sodium (NaCl) 117,434,000 Chloride of magnesium (MgCl₂) 16,428,000 Sulphate of magnesium (MgSO₄) 7,154,000 Sulphate of calcium (CaSO₄) 5,437,000 Sulphate of potassium (K₂SO₄) 3,723,000 Bromide of magnesium (MgBr₂) 328,000 Carbonate of calcium (CaCO₃) 521,000 ----------- For sea-water, total dissolved matter 151,025,000 Aside from the ingredients shown in the above tables, the presence of the following has been proved: iodine, fluorine, phosphorus, silicon, boron, silver, lead, copper, zinc, cobalt, nickel, iron, manganese, aluminum, barium, strontium, arsenic, lithium, cæsium, rubidium, and gold. Oxygen, nitrogen, and carbonic acid gas are also present in quantity. The amount of carbonic acid is estimated to be 18 times as great as in the atmosphere.[140]