Goldstein, Eugen (1850–1930)

German physicist. He investigated electrical discharges through gases at low pressures. He discovered canal rays and gave cathode rays their name.

In 1876 Goldstein showed that cathode rays can cast shadows and that the rays are emitted at right angles to the surface of the cathode. He then demonstrated the deflection of cathode rays by magnetic fields. In 1886 he performed an experiment in which he made holes in the anode and observed glowing yellow streamers coming from the holes. He called these Kanalstrahlen or canal rays. Goldstein later investigated the wavelengths of light emitted by metals and oxides when canal rays impinge on them, and observed that alkali metals show bright spectral lines.

Goldstein was born at Gleiwitz, Upper Silesia (now Gliwice, Poland), and studied at Breslau and Berlin. He worked at the Berlin Observatory 1878–90, and was eventually appointed head of the Astrophysical Section of Potsdam Observatory.

In 1928 he observed that a trace of ammonia was present after the discharge in a tube containing nitrogen and hydrogen. This observation was only followed up much later to see if this phenomenon could have lead to the origination of biologically important molecules, and hence life.