September 5, 1850 – Birth of Eugen Goldstein, discoverer of cathode rays that led to the discovery of isotopes

This German physicist carried out, with the support of the German Academy of Sciences, numerous experiments on electric discharges in a vacuum that led him to the discovery of channel rays that he first reported to the Berlin Academy in 1886 and continued his investigations on the same subject up to about 1915.

Goldstein observed that, when an electric discharge was produced in a tube containing a rarefied gas, using as a negative electrode (cathode) a metallic sheet normal to the axis of the tube and provided with a few small holes, one could see shining rectilinear lines directed from the holes themselves. to the part opposite to that occupied by the positive electrode (anode). If the gas contained in the tube was air, the streaks were yellow.

The rectilinear shape suggested rays that propagated in a straight line, which is why Goldstein gave them the name channel rays.

Thanks to the study of the trajectories of such rays, he would lead Joseph John Thomson and Francis Aston to the discovery of isotopes in 1913.

If you want to know more about this scientist, click on the following link: Eugen Goldstein