D2 notes: Fundamental charge
In 1897, whilst investigating the then mysterious cathode rays in discharge tubes, J.J. Thomson essentially discovered the electron, going on shortly after to determine that particle's charge-to-mass ratio, or specific charge. A few years later, in 1909, Robert Millikan, continuing with what might be called “a tale of two experiments” built on Thomson's discovery by determining the fundamental charge. The electron is...