JJ Thomson, British physicist, 1896-1916. Joseph John Thomson (1856-1940) discovered the electron and was a pioneer of nuclear physics. In 1896 at Cambridge he began experiments on cathode rays, demonstrating that they were in fact particles with a negative charge and were much smaller than an atom. These particles were later renamed electrons. He was awarded the Nobel Prize for Physics in 1906 and was knighted in 1908. (Colorised black and white print).