Sounding device made by William P. Trowbridge for Coast Survey.Line would pay out of a descending cylinder and stationery cylinder on deck.Similar to modern bathythermograph copper wire instrument.Civil War intervened stopping research.Probably would
4/8/2019 11:48:07 AM
Date: 1860
Credit: NOAA Central Library
Subject: Charting
Subject: Soundings
Subject: Bathymetry
Subject: Mechanical