A measure of the quantity of dissolved salts in sea water. It is formally defined as the total amount of dissolved solids in sea water in parts per thousand ((s)) by weight when all the carbonate has been converted to oxide, the bromide and iodide to chloride, and all organic matter is completely oxidized. These qualifications result from the chemical difficulty in drying in salts in sea water. In practice, salinity is not determined directly but is computed from chlorinity, electrical conductivity, refractive index, or some other property whose relationship to salinity is well established. The relationship between chlorinity Cl and salinity S as set forth in ( Knudsen ) 's tables isIFI. In 1940, however, (Lyman) and (Fleming) found that the relationship between total dissolved salts (s) and chlorinity was better expressed by IFI.