This is one of a number of instruments to measure a ship’s speed through the water. In this design, the log uses a spring balance held with the outer tube to record the pull of a rope attached to a log trailed behind the ship. As the inner rod is pulled out it exposes a scale which indicates the ship’s speed. The scale is marked ‘MILES’ and is calibrated from 0 to 16 in eighths of a mile. The design was submitted to the Board of Longitude for testing in 1828.

The top of the main tube has the words ‘Higginson’s Log’ inscribed on it. The tube is held on a pivoted stand with screw holes for attaching it to a ship rail.