Essential Information

Location
Royal Observatory

15 Jun 2014

While the new costume drama 'Belle' strays rather far from the fascinating true story of Dido Belle, an eighteenth-century woman of mixed race raised by British aristocracy - its longitude shout-out is spot on! The last time in the film we see Dido's biological father, Captain John Lindsay, he tearily bids adieu to his daughter in order to oversee a 'longitude experiment' at sea. The real Lindsay was indeed involved in the eighteenth-century search for the longitude. He was in charge of the ship Tartar when it travelled to Barbados in 1764 with John Harrison's famous sea watch (chronometer) 'H4' on board in the care of his son.
John Lindsay, painted in c.1768/1769 by Allan Ramsay (Glasgow Museums).

William Harrison had been told by the Admiralty Office on 4 February 1764 that:
Captain Lindsay of his Majesty’s Ship Tartar, now at Deptford, being directed to proceed as soon as possible to Spithead, where he will receive Orders for proceeding to the West Indies after having assisted at the Observations which are to be made at Portsmouth for the Trial of your Father’s Timekeeper, and he being also directed to receive you, and Mr Thomas Wyatt, your Companion, and the said Timekeeper, with your Baggage, on board the said Ship, and give you a Passage to Barbadoes, in order for your making the second Trial of your Father’s said Time-keeper.
Dido's father therefore appears in both the archives of the Board of Longitude, and in accounts including those of the Harrisons of the observations made on land and at sea in 1764. Lindsay certified to the Admiralty that different elements of the tests took place as directed, and William Harrison also invoked his name when pillorying the astronomer Nevil Maskelyne. Maskelyne had travelled to Barbados some months before the Tartar in order to test both Tobias Mayer's lunar tables and the marine chair invented by Irishman Christopher Irwin.
John Harrison's sea watch H4 (Royal Museums Greenwich).

The younger Harrison recorded that Captain Lindsay agreed it was poor form for Maskelyne to be involved in the chronometer trials when he was reportedly pursuing the longitude rewards himself for the lunar-distance method:
Mr Harrison acquainted Sir John Lindsay with these facts who agreed with Mr Harrison that this being the case Mr Maskelyne must certainly be a very improper Person to take the Observations of equal altitudes, according to Mr Harrison's Instructions from the Board of Longitude. Therefore the next day when they came to the Observatory Mr Harrison told Mr Maskelyne what he had heard & introduced Witnesses to what he said, and did insist that Mr Maskelyne should not observe.
(As discussed before, we do not actually have corroborating evidence that Maskelyne was openly vying for one of the rewards and that this affected his conduct, as Harrison described!)
Detail from 1779 painting of Dido Belle and her cousin, formerly attributed to Zoffany (Wikipedia).

Image sources: Sir John Lindsay - Glasgow Museums; H4 - Royal Museums Greenwich; Dido Belle - Wikipedia.