1924 Fourth Solvay Conference on Physics

First Row L-R: E. Rutherford, Madame Curie, E. H. Hall, H. A. Lorentz, W. H. Bragg, M. Brillouin, W. H. Keesom, I. Van Aubel (Ghent); Row two L-R: P. Debye, A. Joffe, O. W. Richardson, W. Broniewski(Warsaw), W. Rosenhain (Teddington, U. K.), P. Langevin, G. von Hevesy; Row three L-R: L. Brillouin, E. Henriot (Brussels), Th. Dedonder (Brussels), H. E. G. Bauer (Strasbourg), E. Herzen, Aug. Piccard, E. Schrodinger, P. W. Bridgman, J. Verschaffelt (Ghent).