National Archives and Records Admin. National Archives and Records Admin. Archive Photos 1930 Britain, U.S., Japan, France, and Italy sign naval disarmament treaty.
Nazis gain in German elections.
Cyclotron developed by Ernest O. Lawrence, U.S. physicist. Pluto discovered by astronomers. Spain becomes a republic with overthrow of King Alfonso XIII . German industrialists finance 800,000-strong Nazi party. British parliament enacts statute of Westminster , legalizing dominion equality with Britain.