^Millikan oil-drop experiment

In 1913, Millikan measured the charge on an electron precisely using oil-drop experiment. He found that the charge on an oil-droplet was always an integral multiple of an elementary charge, 1.602 × 10^-19 C. Millikan’s experiment established that electric charge is quantised. From the values of charge (e) and specific charge (e/m), the mass (m) of the electron could be determined.