This guest post is by James Poskett, an MPhil student at the History and Philosophy of Science Department at the University of Cambridge. The air there is evidently so full of all things longitude, that James found his way, by accident or design, toward a sounding machine in the Whipple Museum made by Edward Massey, a man who had a number of dealings with the Board of Longitude.

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“Could you, as far as your information of the depth of water enabled you to judge, have got near enough to those ships to have destroyed them?” It was on this question that the court martial of Lord Gambier depended. He was accused of failing to follow up an attack on the French fleet at the Battle of the Basque Roads in 1809. A number of French ships had run ashore and Gambier feared for the safety of the British fleet in following them too close to the shoals, HMS Imperieuse having run aground on the night of April 12th.

It’s easy to think of navigation as all about, well, navigation. But my current research picks up on incidents such as Lord Gambier’s court martial and considers other ways of thinking about the history of depth measurement at sea (or sounding, as it is known). My aim is to show how shifting approaches to naval discipline interacted with the introduction of mechanical sounding equipment.

To start with, I’ve been looking at a brass sounding machine patented by a Mr Edward Massey in 1802. It consists of two numbered dials, unmistakably the product of Massey’s watchmaking background, along with a rotor. This machine would have been attached to a line and thrown overboard, the rotor spinning the dials before locking at the seabed. On hauling in, the depth could be read off the dials as one would read a clock.

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Massey’s wasn’t the first mechanical sounding design but it was the first to be widely adopted by the Royal Navy. In 1807, following a recommendation from the Board of Longitude, the Navy Board ordered 500 of Massey’s machines followed by another 1250 between 1808 and 1811. That’s at least one machine for every Royal Navy ship in commission during the Napoleonic Wars.

What’s intriguing about the adoption of Massey’s machine is how it both relied upon and reinforced new approaches to discipline developing within the Royal Navy at the time. To take one example, naval authorities felt that negligence was hard to identify given that navigational practices often happened out of sight. Prior to the introduction of Massey’s machine, sounding was a case in point. Groups of sailors arranged themselves on the outside of the ship with a lead and line (a simple coil of rope, knotted at set intervals, with a weight attached). This line would then be thrown overboard, out of sight of the officers on the quarterdeck. As the line was hauled in, one of the sailors would either observe or feel for the number of knots. The depth would then by relayed to an officer on deck in the form of a song, “by the mark ten” for ten fathoms and such.

All this changed with the introduction of Massey’s machine. The average sailor in the Royal Navy did not have experience in reading clock-like dials. For this reason, when Massey’s machine was hauled in, it would be taken to the quarterdeck so that an officer could read and record the depth measured. This simple change in practice made the results of sounding more visible to the officers; they no longer had to rely on a song emanating from out of sight. It also made sure that the officer on the quarterdeck took greater personal responsibility for the depths recorded, something the Admiralty considered crucial if they were to successfully court martial disobedient commanders. (Lord Gambier, incidentally, got off the hook.)

Over the summer, I’m going to be taking up a research internship at the National Maritime Museum, exploring in further detail how other sounding devices slotted in to early-nineteenth century naval discipline. At the time, indiscipline was also considered to be a problem related to travel, court martials citing ease of access to Caribbean rum as a cause of lawlessness in the Lesser Antilles. With this in mind, I’ll also be looking at how attempts to keep order in different regions influenced the adoption and use of different sounding machines. Which device faired best in the hands of a drunken sailor still remains to be seen.

[Images: E. Massey, Sounding Machine, NMM NAV0673; 'Measuring the depth of water from a frigate', Wikimedia Commons.]