English English Periscope periscopes English English English English English periscope English periscope English English English English English English English periscopes English English English English English periscope depth periscope English English periscopes English periscope English English English English inventor of the device http://en.wikipedia.org/wiki/Periscope periscopes English periscope English periscopes periscope English Periscope English periscopes English http://en.wikipedia.org/wiki/Periscope English periscope depth English periscope depth en.wikipedia.org/wiki/Periscope English English English English English English periscopes English English periscopes periscopes English English English periscope English periscope English English English English inventor of the device periscope