 Flying from the Pacific to the Atlantic along the route of the Panama Canal construction in a single-engine hydroplane, his passenger and cameraman Ray Duhem filmed parts of the canal during the flight.The film when released was eventually called "The Panama and the Canal from an Aeroplane".That same month, pictures taken by Duhem of fortifications in the Panama Canal Zone, as well as photos of the Presidio of San Francisco (then an active military installation), were published in "Sunset magazine" under the title "" After publication, the Department of War asked the U.S. Attorney in San Francisco, John W. Preston, to investigate the matter.