Hudson River Spies For some months German aliens and nationals had beenquietly moving into O’Brien’s Camp, a resort on .the Hudson just aboveNew York’s 125th Street Ferry. Last week the FBI did some infiltrationof its own. Trapped were an undisclosed number of Germans. Seized bythe FBI: 30 collapsible rubber boats of the type used by the GermanArmy, maps of inland waterways, radios, cameras, field glasses, guns,450 rounds of ammunition. The spy-suspects were whisked to anundisclosed jail.