Charge of the Electron
Measured by R. Millikan (1910)
Millikan produced varying charges on droplets (by cathode rays) and studies there movement in electric field.
finds that charges on each droplet were a multiple of an identical chunk or quanta: 1.6 x 10-19 C, the charge given by an electron to the droplet
mass of the electron: 9.11 x 10-31 kg (1800 smaller than the Hydrogen atom)