Millikan oil drop experiment (R.A. Millikan): A famed experiment designed to compute the electronic charge. The drops of oil were carried past a consistent electric field among charged plates. Subsequent to charging the drop with x-rays, he adjusted the electric field among the plates and hence the oil drop was precisely balanced against the force of gravity. Then the charge on the drop would be recognized. Millikan did this frequently and found that all the charges he calculated came in integer multiples only of a assured smallest value, that is the charge on the electron.