​In 1886, Eugene Goldstein (1850-1930) discovered evidence for the existence of this positively charged particle. Using a cathode ray tube with holes in the cathode, he noticed that there were rays traveling in the opposite direction from the cathode rays. He called these canal rays and showed that they were composed of positively charged particles.

​The proton is the positively charged subatomic particle present in all atoms. The mass of the proton is about 1840 times the mass of the electron.