The rare torpedo discovered by dolphins off the coast of California arrived safely at the Washington Navy Yard on May 30. Naval History and Heritage Command’s Underwater Archaeology Branch now has the remains of the Howell torpedo, a Navy release said. It is only the third one known to exist; the other two are displayed at the Naval Undersea Museum and the Naval War College. Before arriving in D.C., the torpedo was  placed in fresh water, which helps leech the salt out of the artifact, the release said. “It’s kept in water because it was found in a saltwater environment,”…