b. Halifax, Yorkshire, England, November 1626; d India, ca. 1655)
Shakerley was the son of William Shakerley of North Owram, Halifax. After a childhood in Yorkshire and a visit to Ireland, he settled in Pendle Forest, Lancashire, the address on his first surviving astronomical letter, sent to the London astrologer William Lilly in January 1648. The correspondence with Lilly, spanning 1648–1650, comprises nine letters and is concerned largely with patronage and astrology. It also shows that Shakerley first became interested in mathematics around 1646. Over the years Lilly supplied him with books, stationery, and other aids, although he never extended to him the complete patronage he craved.
In 1649 Shakerley was taken into the Towneley household at Carré Hall, Burnley, Lancashire, where he was encouraged in his scientific pursuits. The Towneleys were prominent patrons of learning in the north of England and assisted the astronomers Crabtree and Gascoigne as well as Sharkerley. While in the household of the Towneleys, who were Royalist Catholics, Shakerley continued to correspond with Lilly, a Parliamentarian and a Protestant—seemingly with the full knowledge of Towneley. Nothing is known of Sharkerley’s own religious allegiance, although he appears to have been a latitudinarian Protestant.
Like other practitioners of astronomy in the region, Sharkerley was self-educated, having acquired his knowledge from the works of Kepler and Boulliau, whose achievements he greatly admired, as well as other authors. He was remarkably welversed in the literature of the “new philosophy”; and in his printed works he took great delight in ridiculing more conservative astronomers.
Many of the early letters to Lilly deal with a mixture of astronomical and astrological matters. They show that although Sharkerley had a completely physical explanation for celestial mechanics, he nonetheless accepted that the natural motions of the planets also contained a supernatural element that vindicated his astrological beliefs. A letter describing the appearance of two mock suns in 1648 clearly illustrates this harmony of physical and astrological beliefs, for after giving a purely optical explanation for the mock suns, he invited Lilly to pronounce “astrological judgment” upon them. But as the correspondence progressed, Sharkerley became increasingly skeptical about the validity of astrology, despite his enthusiasm for Lilly’s intention to reform the science.
Sharkerley was the first mathematician to recognize the significance of the work of the Liverpool astronomer Jeremiah Horrocks, whose papers had been acquired by Christopher Towneley and had been taken to Carré Hall after Horrock’s death. In each of his three published works, Sharkerley spoke of Horrocks’ researches with the highest praise, especially his discoveries concerning the lunar theory. When attacking Vincent Wing’s Urania practica (1649), he used material from Horrocks’ surviing papers to frame his own critique of Wing’s faulty lunar theory. The debt to Horrocks was again recognized by Shakerley in his Tabulae Britannicae (1653).
As a supplement to his almanac for 1651, Shakerley predicted a transit of Mercury on 24 October 1651. He described how best to observe it, using the projection method, and enumerates the new astronomical data that could be gained by doing so. Horrocks, who first observed a transit of Venus in 1639, was again cited; and it is clear that Shakerley had access to his unpublished papers on the transit, then at Carrë Hall. He also referred to Gassendi, who in 1631 had been the first astronomer to observe a transit of Mercury. As the 1651 transit would occur during the night in European latitudes, he stated that it would be observed most advantageously in eastern lands.
Probably as a result of his attack on Vincent Wing, Lilly withdrew his support from Shakerley in 1650. No doubt because of the bleakness of his prospects at home, Shakerley emigrated to India. It was from Surat that he observed the Mercury transit predicted in his almanac. The observation began at 6:40 A. M.; but the proximity of adjacent buildings along with other demands on his time prevented him from making more than one sighting, and even this was impeded by his lack of adequate instruments. Mercury appeared to be “brownish black” and was less than half a minute in diameter. This information, and a drawing of the solar disk with Mercury delineated, was sent to Henry Osborne in London. The letter gives no indication as to Shakerley’s occupation in Surat; but it is certain that he did not make the voyage merely to see the transit, as Vincent Wing suggested in 1669. He was probably an employee of the East India Company, although no mention of his name occurs in the company’s records for the early 1650’s.
Apart from reporting the Mercury transit, the Osborne letter relates other astronomical observations, such as that of a comet in 1652. Scarcely any references to astrology occur in this letter, and Shakerley confined himself to reporting purely physical data. While in India he became deeply interested in Brahmin astronomy. By the time of his letter to Osborne in January 1653, he had already learned a considerable amount, especially about the Indian calendar, and promised to devote more time to its study.
Shakerley was the second man ever to witness a Mercury transit, was probably the first Englishman to undertake systematic astronomical observations in India, and was one of the earliest men of science to seriously interest himself in the astronomy of the Brahmins.
After his letter to Osborne in 1653, nothing more was heard of Shakerley, although his Tabulae Britannicae was published at London in the same year. John Booker wrote to him in India in 1655, but he does not record having received a reply. In 1675 Edward Sherburne laconically remarked that Shakerley had “dyed in the East Indies”.
I. Original Works. Twelve of Shakerley’s letters are extant. Eleven are in the Bodleian Library, Ashmole 242 and 423, including his correspondence with Lilly and Osborne. Shakerley’s letter on astrology and the doubts that he entertained therein, sent to John Matteson on 5 Mar. 1649, is published in the Historical Manuscripts Commission Report, Various Collections, 8 (1913), p. 61. Shakerley’s three published works are Anatomy of “Urania Practica” (London, 1649); Synopsis compendiana (London, 1651), his almanac for 1651, which includes a supplement predicting the impending Mercury transit: and Tabulae Britannicae (London, 1653).
II. Secondary Literature. Shakerley obtained posthumous recognition in Vincent Wing’s Astronomia Britannica, 2nd ed. (London, 1669): and in the appendix to Edward Sherburne’s The Sphere of Marcus Manillius (London, 1675).