Many documents now at Greenwich and Cambridge shed light on the life and work of the long-serving Astronomer Royal Nevil Maskelyne, who was an active and widely esteemed figure in early modern European 'science', mathematics and navigation. Maskelyne was also vital to institutionalising and increasing the stature of the Board of Longitude from the 1760s until his death in 1811. He was often the single most active and proactive, and the highest-profile, Commissioner on the Board during this period. His interests, activities and ties to other institutions from the Royal Society to learned dining clubs, greatly shaped and empowered the Board. The Maskelyne sources at Greenwich and Cambridge additionally shed light on the workings of the astronomer's mind -- as he scribbled thoughts and calculations and diagrams across any papers which he had to hand -- and on the inextricable links between his so-called 'professional' and 'personal' lives.

I've just been looking at the volume RGO 4/187 at Cambridge, which consists of 48 letters sent to Maskelyne from 1765 (the year before he became Astronomer Royal) to 1809 (two years before his death). These letters, while limited in number, provide a sort of cross-section of the astronomer's many interests, activities, and intersecting relationships and institutional ties. Many are also overlaid with later notes on his darting thoughts. The letters hail from around the globe and touch upon Maskelyne's work on astronomy (at home and for expeditions), the Board's publication of the annual Nautical Almanac and other texts, the lunar-distance and Jovian moon methods of finding longitude at sea and on land, specific longitude projectors, and the use and complications of instruments such as the sextant.

Others are announcements seeking Maskelyne's presence at many of the institutions with which he was involved, as when Lord Sandwich (yes, that Sandwich!) requested that he attend the election of a Professor of Chemistry at the University of Cambridge in 1772 in the hope of swinging the vote towards a candidate from their alma mater, Trinity College. There are also a number of announcements of meetings of the Royal Society, of which the astronomer had been elected a Fellow in 1758, such as that above from 1793. All of these documents were later covered in Maskelyne's calculations and geometric sketches. Some letters involve the purchase of a pocket globe and a telescope with a six-foot focal length from George and Peter Dollond in 1807 and 1808. A small number of letters address the workings of the Board of Longitude or the Royal Observatory, such as the Board's oversight committee including Joseph Banks reviewing accounts in 1798, an upcoming official visitation of the Royal Society to the Observatory in 1801, and samples of papers under consideration for use in publications in 1804.

Other letters in this volume mainly revolve around the astronomer's personal life, which complements the personal manuscripts including diaries and correspondence which are now held at the National Maritime Museum. Such interpersonal relationships and expressions of good will commonly greased the cogs of Georgian society, business and institutions. For example, in 1795 James Stuart Mackenzie, the Lord Privy Seal of Scotland (then retired from politics) and amateur astronomer, invited Maskelyne to dinner and addressed him as 'My Dear Tycho' in reference to the astronomer Tycho Brahe. He had originally sent the invitation to the Royal Society, but it missed its recipient. The same year, Mr Rowed of the Globe Tavern in Fleet Street in London wrote about an upcoming club meeting at the astronomer's house. In a letter of 1785, Charles Hutton, professor of mathematics at the Royal Military Academy, also mentioned a meeting of the club when he wrote about various subjects including A Mathematical and Philosophical Dictionary upon which he was working. Hutton had been foreign secretary of the Royal Society until Joseph Banks organised his ouster in 1783, which eventually led to the resignation of he and other mathematicians from the Society. Again, this letter has been covered, back and front, with calculations and sketches.

In 1799, William Manwaring of Paddington in London wrote about sending Maskelyne and his wife and daughters presents of pears and a pair of pigeons which he had bred (below). Dr. Layard, in an undated note, sought Maskelyne's vote for a candidate at the British Lying-in Hospital and thanked him for having obtained the proxy votes of his in-laws, the Ladies Clive (his sister Margaret having married Robert Clive). This was presumably Daniel Peter Layard, a successful man-midwife and physician. Other correspondents paid their compliments, some as friends seeking a meeting and some as strangers. As an example of the latter, William Marsden wrote from Fort Marlborough in Bengkulu in Indonesia in 1772 (the letter only reaching Greenwich eights months later) apologising for approaching the astronomer without an introduction and then praising his British Mariner's Guide and method of finding longitude, and relating his own observations made with the Captain's sextant. Marsden concluded that, 'Any Service in my power on this Coast will be a pleasure to me to Perform you'.

Correspondents sometime also introduced others to Maskelyne, as when at the end of his letter of 1799, Thomas Wright wrote: 'I beg leave to introduce Mr. Webber to the honor of your correspondence;- He is a person of Merit and of great application to the objects of his profession'. This was the American astronomer Samuel Webber, who had recently assisted Wright, the surveyor general of the colony of St. John's Island, in taking accurate sightings to establish the positions of the various rivers then claimed to be the border between New Brunswick and the District of Maine in Massachusetts. The correspondents represented in this volume are mainly British, including those posted or travelling abroad, but include a small number of contacts from foreign nations as well. The Britons mainly included astronomers and computers, and members of the government and Naval and military establishments (including the soon-to-be-deposed Governor William Bligh of New South Wales, of 'Mutiny on the Bounty' infamy).

Most of these correspondents were male, with Mary Edwards of Ludlow being a notable exception. As Mary Croarken has written about in different articles, Edwards was a highly unusual female contributor to the 'search for the longitude', having been a long-serving 'computer' (calculator) for the annual Nautical Almanac. Edwards first assisted her husband John, whom the Board of Longitude awarded £20 and £200 in 1778 and 1780 for his work on the metals for reflecting telescope mirrors, and then entirely replaced him as computer when he died in 1784. A year later, she wrote to direct and to thank Maskelyne for assisting with settling her late husband's accounts with renowned London instrument makers including Edward Troughton and Edward Nairne and in transporting her husband's instruments back and forth for sale. Again, the back of Edwards's letter is covered in notes and sketches.

On the foreign side, two officers of the War Ministry in Madrid in Napoleonic Spain conveyed observations of a solar eclipse made by Ali-Beik Abd-Allah at Tangier in 1803. Three years later, Julian Canelas wrote from an observatory on the Isla de León (between the city of Cádiz and the Spanish peninsula) to ask for observations of a recent solar eclipse and of the occultations of Antares to compare with his own. Gian Giuseppe Barzellini sent a paper about his calculation of the altitude of pole of the Austrian Habsburg city of Gorizia for a solar clock in 1774. Barzellini, whose papers and books are now held at the theological seminary in Gorizia, was the first director of its insurance bank, worked with the local agrarian reform society, and conducted a land survey of the province. He says in the letter that he taught himself mathematics, astronomy and instrument design by studying publications. Four years after this, he constructed a meridian line on the exterior wall of the cathedral. It was not unusual for such partially or wholly self-taught enthusiasts to contact Maskelyne for his opinion or to try to contribute to larger astronomical efforts.

Of perhaps the greatest interest to aficionados of the longitude and of the story of the great clockmaker John Harrison is an undated draft letter (above) of c. 1765 from Maskelyne to 'My Lord'. In it, the Astronomer Royal first responds to Harrison's applications to the Board of Longitude and to Parliament to get a second £10,000 in reward money for his marine timekeepers - despite refusing to produce two more watches and to otherwise submit to the trials required by the legislation of 1765. The astronomer then asks to provide his correspondent with an abstract and explanation of the Act of 1714, which he had at first intended 'as an introduction to an answer to Mr. Harrison's scandalous [originally written as 'abusive'] pamphlet on my trial of his watch at the Royal Observatory; tho I afterwards dropt the design of publishing the same thinking such abuse thrown out without probability or proof required no refutation'. Maskelyne never responded in published form to the slights from John and his son William, put forth in the 1765 pamphlet A Narrative of the Proceedings relative to the Discovery of the Longitude at Sea and in other media including newspapers and journals - although anonymous supporters of his or the Board's cause did rally in the media.

While my photos of these illuminating resources are not of the best quality, it shouldn't be that many more months before the project to digitise these records posts high-resolution images and complementary materials online!

Image sources: Alexi Baker / Cambridge University Library.