Jasper S. Bilby observing from reconnaissance pole attached to tree.Top of pole is 104 feet above ground.Checking for intervisibility between stations.Helping plan for necessary height of tower at station
3/18/2019 3:06:41 PM
Date: 1903
Credit: NOAA, John Hayford Album
Location: Minnesota
Subject: Geodesy
Subject: Triangulation
Subject: Towers
Subject: Wooden