Explain the discovery of the electron.

(N/A) The discovery of the electron was made by $J.J. \text{ Thomson}$ in $1897$ using a cathode ray discharge tube experiment.
$1$. $A$ discharge tube made of glass containing two thin pieces of metal,called electrodes,was sealed in it.
$2$. Electrical discharge through the gases could be observed only at very low pressures and at very high voltages.
$3$. When a high voltage was applied across the electrodes,a stream of particles started moving from the negative electrode (cathode) to the positive electrode (anode).
$4$. These were called cathode rays or cathode ray particles.
$5$. When these rays were passed through an electric field,they were deflected towards the positive plate,indicating that they carry a negative charge.
$6$. $J.J. \text{ Thomson}$ determined the charge to mass ratio $(e/m_e)$ of these particles,which were later named electrons.