Antimony and gold sols have been prepared and their precipitation values studied by KCI, BaCl2, and AlCl3 by employing the light extinotion and the surface leaving methods in the light of the equation \(C= a+ {m.1/t \over n+1/t}\) On adding different concentrations of these electrolytes to the sol the corresponding times of coagulation have been determined by light extinction and visual surface leaving method. The times of coagulation by both the methods could not be expected to be identical, because the stage of coagulation may not be the same, when different techniques are employed. The merit of this equation, however, is not affected, in as much as the relation between 1/C—a of the electrolyte and their respective times of coagulation has been found to be linear. The constants \(a\), \(m\), and \(n\) have been determined for each electrolyte.