Ran across this today. Had to share. No global positioning satellites in the '30's of course, but this was pretty cool. Anybody ever see one?
http://www.navigadget.com/index.php/2010/07/13/antique-gps-system-from-1930s
http://www.navigadget.com/index.php/2010/07/13/antique-gps-system-from-1930s