Robert Peary North Pole Expedition.Sounding with piano wire through the ice.Profile of soundings tends to corroborate that Peary made it to the North Pole.
4/8/2019 11:48:09 AM
Date: 1909
Credit: National Geographic Magazine, September 1988
Location: Arctic Ocean
Subject: Charting
Subject: Soundings
Subject: Bathymetry
Subject: Mechanical