2 6 8 D O C U M E N T 2 7 1 S E P T E M B E R 1 9 2 8 271. To Nobel Prize Committee for Physics Scharbeutz, 25 September 1928 In reply to your query regarding the conferral of the Physics Prize for 1929, I note the following: In my opinion, the most important secure achievement in physics that has not yet received the prize is the recognition of the wave nature of mechanical phenomena. De Broglie was the first to predict that particles in motion are accompanied by a wave process, but he did not consider the possibility of an experimental proof.[3] The two American researchers were the first to show the existence of such waves experimentally,[4] although at the same time, or nearly the same time, other re- searchers carried out less conclusive experiments in the same area.[5] This is a difficult case, since De Broglie was the decisive initiator, but he did not exhaust the possibilities in this area. With equal priority, the theoreticians Heisenberg[6] together Schrödinger[7] 1 Nobel Prize should be considered (for 1930?). On the basis of their achievements, each of these researchers has indeed earned a whole Nobel Prize, although their theories are in reality practically equivalent. However, in my opinion De Broglie should take precedence for receiving the prize, especially because his ideas are with certainty in agreement with empirical facts, while it indeed remains questionable as to how much of the grandiosely conceived ideas of the two last-named researchers will remain in the end. In awarding the prize to De Broglie, one encounters on the one hand the diffi- culty that his achievement by itself does not represent a final step, and that it is rel- atively hard to decide which researchers should have a claim to the other half of the prize my suggestion as given above is not an ideal solution, but it is the best that has occurred to me. {De Broglie[1] Davison together and a collaborator[2] 1 Nobel Prize . 1 2 1 2