Black and white photographic print, showing a nuclear explosion due to cosmic rays, yielding three highly-ionising particles together with an electron

Black and white photographic print from a negative, from a negative by Pierre Auger and Paul Ehrenfest at the International Foundation High Alpine Research Station Jungfraujoch, Switzerland, and display label, mounted on passe partout board minus frame, showing a nuclear explosion due to cosmic rays, yielding three highly-ionising particles together with an electron, unsigned, Europe, 1936