, Dittmar's Principle (or rule of constant proportion
) can be used to calculate the concentration
of certain constituent
s of sea water, by measuring the concentration
of another component
use this principle to e.g. find the concentration of salt
by measuring the amount chloride ion
The principle is named after Wilhelm Dittmar, who first discovered the constant proportions of the seven major components of sea water (besides hydrogen and oxygen, that is); sodium, calcium, magnesium, potassium, chloride, bromide and sulfate.