Nevil Maskelyne Research Articles

John Frank Allen. 6 May 1908—22 April 2001

John Frank (Jack) Allen was a Canadian-born pioneer of low temperature physics. With his graduate student, Don Misener, he discovered the phenomenon of superfluidity on passing HeII through very narrow glass capillaries. Simultaneously, and independently, the phenomenon was discovered by Piotr Kapitza FRS in the Soviet Union. Jack's most famous discovery in 1938 was the fountain effect in liquid HeII, a further manifestation of the role of superfluidity at very low temperatures. The Nobel Prize for the discovery of superfluidity was awarded to Kapitza in 1978. Jack invented the O-ring as a reliable vacuum seal and, in 1947, followed this by the indium-ring cryogenic seal. In 1958, with John Bardeen (ForMemRS 1973) and Jan de Boer, he initiated a project that saved three million cubic feet of helium gas from being lost to the world. After running the Mond Laboratory in the Cavendish Laboratory from the late 1930s, in 1947 he was appointed professor of natural philosophy at St Andrews University, where he led the construction of a new physics building and built up an internationally respected department. He campaigned for student representation, and was well known for his physics demonstrations. In later life, he carried out a programme to erect plaques to Nevil Maskelyne FRS, who measured the gravitational constant G , and to celebrate the achievements of St Andrews luminaries.

The Scientific Wanderjahr of Vilnius Astronomer Andrew Strzecki in 1777–1778

Abstract: In 1777–1778, astronomer Andrew Strzecki (Polish Andrzej Strzecki, Lithuanian Andrius Streckis, 1737–1797) from Vilnius went on a scientific journey to Western Europe, visiting Vienna, Paris, London, and some other cities. This article aims to investigate and describe the motives, chronology, itinerary, and outcomes of this journey, and to evaluate the importance of this event for the science history of Vilnius and Europe. The research is based on an analysis of original correspondence, with some of the letters mentioned in print for the first time. The narrative method was applied to create a coherent storyline from the incomplete data found in various manuscripts and other sources. The research sheds light on previously obscure details of Early Modern European scientific communication, among them, the connections between astronomers of Vilnius and Vienna. The article also mentions the circumstances of the events, which were essential in the history of Vilnius University: the election of Marcin Poczobut Odlianicki (Lithuanian Martynas Odlianickis Počobutas, 1726–1810) as a member correspondent of the Paris Academy of Sciences and international recognition of the constellation he introduced, Taurus Poniatovii. The article confirms that the social and scientific ties of astronomers in Vilnius were much broader than what is usually described and included their close personal relationships with some of the first-rated scholars of the era, such as Rugerius Boskovich, Nevil Maskelyne, and Benjamin Franklin.

GRAVITATIONAL CONUNDRUM: CONFUSING CLOCK-RATE MEASUREMENTS ON THE 'FIRST FLEET’ FROM ENGLAND TO AUSTRALIA

Voyages of exploration often included astronomers among their crew to aid with maritime navigation. William Dawes, a British Marine who had been trained in practical astronomy, was assigned to the 'First Fleet’, a convoy of eleven ships that left England in May 1787 bound for Botany Bay (Sydney, Australia). Dawes was also expected to take measurements of the local gravitational acceleration, g, at any port of call by measuring the daily rate by which his Shelton pendulum clock differed from that at Greenwich, its calibration location. Although Dawes and Nevil Maskelyne, Britain’s fifth Astronomer Royal, had planned to obtain clock-rate measurements in the Canary Islands, San Sebastian (Rio de Janeiro) and Table Bay, Captain Arthur Phillip, Commander of the First Fleet, only allowed Dawes to disembark the clock in Rio de Janeiro. Therefore, we have just one set of clock-rate measurements from the voyage, in addition to land-based measurements obtained in New South Wales. If gravity was the dominant factor affecting the clock’s changing rate, Dawes’ measurement of –48.067 sec per (sidereal) day obtained in Rio de Janeiro implies a local gravitational acceleration, <italic>g</italic> = 9.7946 m sec^–2. On the other hand, if we adopt the modern value, <italic>g</italic> = 9.7878 m sec^–2, the implied daily decay rate is almost exactly 30 sec greater than Dawes’ clock-rate determination, a difference that is well in excess of the prevailing uncertainties. This suggests that the pendulum’s regulator nut may have been offset by a full turn, thus implying that our assumptions regarding the pendulum length may have to be revisited.

Reanalyses of Maskelyne's tidal data at St. Helena in 1761

Abstract. The construction of an electronic data set of the tidal measurements made at St. Helena in 1761 by Nevil Maskelyne is described. These data were first analysed by Cartwright (1971, 1972) in papers which have importance within studies of changing tides. However, Cartwright's data files were never archived for the benefit of other researchers, demonstrating that “old data” at risk can sometimes take the form of electronic rather than paper records. In the present paper, the newly digitised Maskelyne data have been reanalysed by several techniques in order to obtain an updated impression of whether the tide has changed at that location in over two and a half centuries. This new data set may be found via https://doi.org/10.5285/e66db85a-eaae-6665-e053-6c86abc0bfb9 (Woodworth and Vassie, 2022). Our main conclusion, consistent with that of Cartwright, is that the major tidal constituent (M2) has changed little. However, the results of the various techniques demonstrate how difficult it is to obtain reliable conclusions for the smaller constituents.

SYDNEY'S SCIENTIFIC BEGINNINGS: WILLIAM DAWES' OBSERVATORIES IN CONTEXT

The voyage of the 'First Fleet' from Britain to the new colony of New South Wales was not only a military enterprise, it also had a distinct scientific purpose. Britain's fifth Astronomer Royal, Nevil Maskelyne, had selected William Dawes, a promising young Marine with a propensity for astronomical observations, as his protégé. Maskelyne convinced the British Board of Longitude to supply Dawes with a suite of state-of-the-art instruments and allow the young Marine to establish an observatory in the new settlement. The Astronomer Royal may have had a dual motivation, one driven by strategic national interests combined with a personal investment linked to the suggested re-appearance of a comet in the southern sky. With the unexpected assistance of the French Lapérouse expedition, between 1788 and 1791 Dawes established not one but two observatories within a kilometre of Sydney's present-day city centre. Motivated by persisting confusion in the literature, we explore the historical record to narrow down the precise location of Dawes' observatories. We conclude that the memorial plaque attached to Sydney Harbour Bridge indicates an incorrect location. Overwhelming evidence in the form of contemporary maps, charts and pictorial representations implies that Dawes' observatory was located on the northeastern tip of the promontory presently known as The Rocks (formerly Dawes' Point), with any remains having vanished during the construction of the Harbour Bridge in the 1920s and 1930s.

The attraction of the pyramids: virtual realization of Hutton's suggestion to improve Maskelyne's 1774 Earth&amp;#160;density estimate

Abstract. Charles Hutton suggested in 1821 that the pyramids of Egypt be used to site an experiment to measure the deflection of the vertical by a large mass. The suggestion arose as he had estimated the attraction of a Scottish mountain as part of Nevil Maskelyne's (1774) “Schiehallion Experiment”, a demonstration of Isaac Newton's law of gravitational attraction and the earliest reasonable quantitative estimate of Earth's mean density. I present a virtual realization of an experiment at the Giza pyramids to investigate how Hutton's concept might have emerged had it been undertaken as he suggested. The attraction of the Great Pyramid would have led to inward north–south deflections of the vertical totalling 1.8 arcsec (0.0005∘), and east–west deflections totalling 2.0 arcsec (0.0006∘), which although small, would have been within the contemporaneous detectable range, and potentially given, as Hutton wished, a more accurate Earth density measurement than he reported from the Schiehallion experiment.

Manuel Johnson's tide record at St. Helena

Abstract. The astronomer Manuel Johnson, a future President of the Royal Astronomical Society, recorded the ocean tides with his own instrument at St. Helena in 1826–1827, while waiting for an observatory to be built. It is an important record in the history of tidal science, as the only previous measurements at St. Helena had been those made by Nevil Maskelyne in 1761, and there were to be no other systematic measurements until the late 20th century. Johnson's tide gauge, of a curious but unique design, recorded efficiently the height of every tidal high and low water for at least 13 months, in spite of requiring frequent re-setting. These heights compare very reasonably with a modern tidal synthesis based on present-day tide gauge measurements from the same site. Johnson's method of timing is unknown, but his calculations of lunar phases suggest that his tidal measurements were recorded in Local Apparent Time. Unfortunately, the recorded times are found to be seriously and variably lagged by many minutes. Johnson's data have never been fully published, but his manuscripts have been safely archived and are available for inspection at Cambridge University. His data have been converted to computer files as part of this study for the benefit of future researchers.

Notes on Contributors

Notes on Contributors

Book Review: Transits of Venus: Chasing Venus: The Race to Measure the Heavens

TRANSITS OF VENUS Chasing Venus: The Race to Measure the Heavens. Andrea Wulf (William Heinemann, London, 2012), Pp. xxvi + 304. £17. ISBN 978-0-434022-108-6.Readers of this journal will naturally appreciate the timing of this account of the attempts to observe and measure the two eighteenth-century transits of Venus, astronomical events that were the focus of international cooperation and competition. Unlike some of her cast of characters, Andrea Wulf fortunately ensured that everything was ready in good time for the 2012 transit.Wulfs account is a bold attempt to weave together the various stories of the expeditions sent across the globe to observe the transits of 1761 and 1769. Their aim was to provide an improved figure for the size of the solar system from the comparison of observations in different locations. This was a project Edmond Halley had encouraged future astronomers to undertake, knowing in 17 16 that he would not live to the 1760s. With the baton taken up by Joseph-Nicholas Delisle, Nevil Maskelyne and others, Halley's successors attempted to do him proud in their efforts half-a-century later.Telling the story of both transits allows Wulf to make some interesting contrasts. With the 176 1 transit taking place during the Seven Years War - 'the first global war' , we are told (p. 4) - she is able to make much of the difficulties faced by observers such as Le Gentil, Pingre and Mason and Dixon, who all found themselves caught up in the conflict and had to alter their plans accordingly. For other observers, climate was the main challenge. Jean-Baptiste Chappe d'Auteroche, for example, endured sub-zero temperatures as he raced to his intended observing station in Siberia. By 1769, however, Europe was more or less at peace and patronage was easier to secure. Monarchs including George UJ in Britain, Catherine the Great of Russia, and Christian IV of Denmark saw transit expeditions as vehicles for national pride and supported them accordingly. These later expeditions were much better provisioned, therefore, and greatly benefitted from lessons learned in 1761, although they remained subject to the vagaries of the weather (as UK observers experienced only too clearly in 20 1 2).This is a popular history, albeit one that has been fully researched and well referenced. As such, the book follows some of the genre's trends, notably in its attempts to evoke atmosphere and character and to inject drama into the narrative. …

Maskelyne: a timely celebration

Sir Nevil Maskelyne is remembered by many as the main rival to clockmaker John Harrisonin the famous Longitude affair of the 18th century. However, his contributions to science gowell beyond this often misreported drama; three of his many observations anddevelopments are considered here in the year marking the 200th anniversary of his death.

Into the breeches: recasting the villain of Longitude

Astronomer Nevil Maskelyne looked faintly ridiculous in his padded observing suit. Surely not the kind of outfit a spoiler would wear

Dawes Point

The promontory at the western end of Circular Quay was known to the Aboriginal people as Tar-Ra. It was chosen as the site for an observatory by Lieutenant William Dawes, who arrived with the first Europeans. Dawes came with a recommendation from the Astronomer Royal, Dr Nevil Maskelyne, and some instruments from the Board of Longitude, with which to study the heavens. The point was initially named Maskelyne Point, but as Dawes lived there while he was in the colony from 1788 until 1791, the area became known as Dawes Point.Dawes kept the colony's first meteorological records here, and it was also here that Dawes pinned the town's first clock to a rock face. He encouraged friendship with local Aboriginal people, including a young girl Pategarang, from whom he learned some of the language of the Cadigal people. Dawes's notebooks, held in the School of Oriental and African Studies at the University of London, remain one of the most precious records of the local language.

An investigation of the eighteenth-century achromatic telescope

Summary The optical quality and properties of over 200 telescopes residing in museums and private collections have been measured and tested with the goal of obtaining new information about the early development of the achromatic lens (1757–1770). Quantitative measurements of the chromatic and spherical aberration of telescope objective lenses were made and are discussed within the context of John and Peter Dollond's description of their efforts to overcome these two optical defects inherent in any single lens. Their work was chronicled in the Philosophical Transactions of 1758 and 1765. An important finding of this investigation is that a particular form of the achromatic lens that has been suggested as being a rare and early form by some investigators, and presumably introduced by Chester Moor Hall, was in fact found to be numerous and present in most museums and many private collections. It is shown that the colour correction of an early eighteenth-century doublet telescope objective is very sensitive to the ratio of the flint to crown glass focal lengths, as well as the variations of the indices of refraction with colour. This sensitivity would preclude any simple recipe for constructing an achromatic lens. The third order theory of spherical aberration of Nevil Maskelyne is reexamined, in which he pointed out that John Dollond developed a theoretical formula equivalent to what today is called geometric third order spherical aberration theory.

“To demonstrate the exactness of the instrument”: Mountainside Trials of Precision in Scotland, 1774

ArgumentThe British Astronomer Royal, Nevil Maskelyne, spent four months on a Scottish mountainside in 1774, making observations of zenith stars and coordinating a detailed survey of the size and shape of the mountain Schiehallion, in order to demonstrate and quantify what was known as “the attraction of mountains.” His endeavors were celebrated in London, where it was stated that he had given proof of the universality of Newtonian gravitation and allowed for a calculation of the relative densities of the earth as a whole and the earth near its surface. This paper argues that the “Schiehallion Experiment” was as much a trial of the precision of Maskelyne's instruments and their expert management as it was a trial of Newtonian theory. By tracing the biography of the key instrument used by Maskelyne, his zenith sector, we see how much personal credibility was a stake for him in Scotland. By considering the mountainside as a place to test and reveal the precision of astronomical instruments we see a link between the Scottish endeavors and Maskelyne's ambitions for the Greenwich Observatory.

John Playfair on Schiehallion, 1801–1811

Abstract John Playfair first visited the Scottish mountain, Schiehallion, during Nevil Maskelyne's 1774 plumbline deflection experiment, which was conducted to measure the density of the Earth. The mathematician Charles Hutton analysed the survey data from the experiment, reporting the mean Earth specific gravity as 4.5 in 1778. Playfair undertook a lithological mapping exercise in 1801, to improve the accuracy of Hutton's estimate, and reported a range of 4.56–4.87 in 1811. The computation of the gravitational effect of topography with variable subsurface density effectively made him the creator of the first geophysical model. As such, not only was Playfair's Schiehallion contribution pioneering in itself, but it was representative of his more significant works in both mathematics and geology, in that he built on existing benchmark work with novel and valuable additions of his own. Although Playfair's map of the extent of the Schiehallion quartzite was quite accurate, the Society's fourth President, John MacCulloch, having visited Schiehallion, was dismissive of Playfair's representation of the subsurface density variation. MacCulloch spent several years searching Scotland for a more favourable site for a plumbline experiment, travels that allowed him to compile the data for his 1836 geological map of Scotland.

Maskelyne’s 1774 Schiehallion experiment revisited

Synopsis Nevil Maskelyne’s 1774 experiment on the Scottish mountain Schiehallion set out to derive the mean density of the Earth, from astronomical observations of the deflection of the vertical and calculation of the mountain’s relative gravitational attraction. Using Maskelyne’s results and lithological survey results, John Playfair estimated mean Earth specific gravity to be 4.56–4.87, while Charles Hutton argued in 1821 that the Earth was ‘very near five times the density of water; but not higher’. Hutton challenged future workers to identify any areas in which his analysis could be improved. The geometry of the 1774 experiment has therefore been recomputed within a digital elevation model extending 120 km from the mountain. Three contributions to the deflection of the vertical have been included: topography, and local and regional subsurface density variations. Local subsurface densities have been modelled using geological maps, cross-sections and laboratory measurements. Regional subsurface effects have been included from analysis of the Bouguer gravity anomaly. The outcome of the new modelling is to credit Maskelyne for his accurate astronomical observations, as together with the new density structure model, they yield a mean Earth density of 5480 ± 250 kgm −3 , in agreement with the modern value of 5515 kg m −3 .

Discovery of the Missing Correspondence between Carl Friedrich Gauss and the Rev. Nevil Maskelyne (1802–5)

More than 30 years ago in Annals of Science, Dr. Eric Forbes of the University of Edinburgh published the correspondence between Carl Gauss and Great Britain's Astronomer Royal, Nevil Maskelyne. Five of the letters he listed as missing have now been discovered, along with two entirely new letters he was unaware of. Their nearly complete correspondence can now be read for the first time in 200 years.

Observations of planetary transits made in Ireland in the 18th Century and the development of astronomy in Ireland

We review the small number of known observations of planetary transits made in Ireland in the 18th century with particular reference to the 1769 observations of Venus by Charles Mason. Though inconclusive, there is evidence to suggest that planetary transits were instrumental in the foundation of at least one of the principal observatories in Ireland. In addition, we note the close personal involvement and the contributions of Nevil Maskelyne, the prime mover of the UK 1769 Transit observations, in the design and equipment of these observatories.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Astronomical labourers: Maskelyne's assistants at the Royal Observatory, Greenwich, 1765-1811

Nevil Maskelyne FRS held the post of British Astronomer Royal from 1765 to 1811. As Astronomer Royal, Maskelyne's main task was to ensure that the positions of the Sun, Moon, planets and stars were regularly observed and that those observations were published in an accessible form. To do this, and simultaneously to maintain his role within London's scientific society, Maskelyne hired an assistant to undertake the routine work of the Observatory. This paper considers Maskelyne's assistants at the Royal Observatory, Greenwich, identifies who the assistants were, and describes their working conditions.

Tabulating the heavens: Computing the Nautical Almanac in 18th-Century England

The question of how to accurately find longitude at sea was hotly debated in the mid-1700s. This article describes the lunar distance method, promoted by Nevil Maskelyne, the British Astronomer Royal. In 1767, Maskelyne began publishing the Nautical Almanac, which contained astronomical tables prepared by a small network of human computers during the period 1765-1809. This article will describe the computing system Maskelyne created to compute the necessary tables.