‘Charts drawn in blood’
Guest blog composed by one of our history of science interns, Stuart Jennings
‘Charts drawn in blood’: Observatory Chronometers and the 1822-26 Royal Navy survey of Africa
In the ‘Time and Longitude’ gallery of the Royal Observatory, John Arnold’s chronometer number 323 is celebrated for its service on Belcher’s expedition to search for the remains of Franklin’s lost Arctic voyage. However, as the ledger of issue and receipt beside it suggests, chronometers had long lives and took part in many different adventures. The first entry refers to the voyage of Captain Owen and the HMS Leven, where Arnold 323 joined several other instruments including No. 163 by George Margetts and No. 10 by Paul Philip Barraud, which currently sit behind the glass of the ‘Time for the Navy’ exhibit. These unassuming instruments played important roles in Owen’s expedition, one of the most significant yet underappreciated scientific voyages of the 19th century.
Setting off from Deptford, likely using the time ball of the Observatory at Greenwich to rate their chronometers, the ships Leven and Barracouta proceeded to the Cape of Good Hope, where they obtained astronomical readings with the help of the observatory that the Board of Longitude had recently set up there.
The expedition proved to be enormously difficult and dangerous. The best account, which survives in its original form in the Caird Library at the National Maritime Museum, is given by Lieutenant Thomas Boteler of the Barracouta. He describes the perils of hostile local tribes, ships running aground and attacks from dangerous animals, but most of all from the ‘Fever’, malaria. This ravaged the crew, resulting in the deaths of over half of the men who left England. A later Navy Hydrographer would remark that their charts ‘…may be said to have been drawn and coloured with drops of blood.’
Despite this adversity, Owen and his crew mapped nearly 30,000 miles of coast and produced charts that informed generations of navigators to come. The voyage also provides several useful case studies of the different roles that chronometers played on long surveys, the Observatory’s instruments chief among them.
Barraud 10, though originally supplied to the Barracouta, proved unreliable and was downgraded from navigational to short-interval timing and transferred to the Leven. It accompanied Richard Owen on a river survey in which 12 out of 19 crew died, was then rescued from the tender when it ran aground and finally supplied to its replacement, the Albatross. After repair in England it accompanied Capt. Owen again aboard the HMS Eden.
We know less about Margetts 163 as it stayed on the Barracouta and most evidence refers to the Leven, but it also appears to have been downgraded after it was found to be faulty, continuing to help on the survey of Africa’s west coast.
Arnold 323 was sent out by the Admiralty in 1825 to replace Arnold 503, which had broken. Through various letters we can track the progress of 323, which was sent down from Portsmouth and took Arnold 498’s place as the standard on board the Leven, thereby becoming the most important chronometer on the voyage.
Each of these chronometers tells us interesting things about the ways in which they could be used and re-used, reminding us that every object has many stories to tell.