1919    June-Rutherford creates oxygen from nitrogen. 

1920    Rutherford speculates on the existence of the neutron at the Royal Society.

1931    November-Urey discovers deuterium.

1932   	February-Chadwick discovers the neutron. 

1933	April-Born, Courant, Franck and many other scientists are compelled to 
	leave the University of Göttingen because of their “Jewish physics”.
	October-Szilard recollects that “It occurred to me in October, 1933 that a chain
	reaction might be set up if an element could be found that would emit two 
	neutrons when it swallowed one neutron.” This idea became a classified 
	British patent in 1935 before the fission was discovered.