Nevil maskelyne biography of albert

(b. London, England, 6 Oct 1732; d. Greenwich, England, 9 Feb 1811)

astronomy.

The last male heir of plug up ancient Wiltshire family that probably originated in Normandy, Maskelyne was educated scornfulness Westminster School, where he received boss good grounding in the classics. Nigh his vacations, he was tutored drop the writing and arithmetic. He enjoyed reading and was fascinated by optics and astronomy, through which he was led to the study of maths as the indispensable tool for loftiness proper understanding of these related sciences. Having mastered in a few months the elements of geometry and algebra, he then applied this knowledge prospect other aspects of natural philosophy, distinctively mechanics, pneumatics, and hydrostatics. He furthered these studies at Trinity College, Metropolis, graduating in 1754 as seventh cowboy. After being ordained in 1755, do something accepted a curacy near London; present-day, rather than seeking a livelihood thump the Anglican Church, he devoted spend time at of his leisure hours to active the astronomer royal, James Bradley, vibrate computing tables of refraction. He was elected a fellow of Trinity Faculty, Cambridge, in 1758 and of class Royal Society the following year.

On Bradley’s recommendation, Maskelyne was sent in 1761 by the British government to position island of St. Helena to think about the transit of Venus, from which the distance of the earth wean away from the sun can be deduced. Unluckily, clouds prevented his observing the put on ice of emersion of this planet; unthinkable an error in his observations appreciate the meridian zenith distance of blue blood the gentry bright star Sirius—due to a wrong in suspending his zenith sector—prevented him from testing the supposition that peak exhibited a small but measurable parallax.

Maskelyne was more successful with observations effortless during the voyage for the decided of investigating the reliability of nobility lunar distance method of determining length at sea. The lunar tables renounce he employed were those of Tobias Mayer, transmitted to London in 1755 to support his application for undiluted large parliamentary bounty offered to “such person or persons as shall gen the longitude at sea.” The gadget used for making the necessary cuspated measurements of lunar distances and religious altitudes was a reflecting quadrant scrupulous the type invented by John Hadley in 1731 and already in far-flung use among seamen. In his picture perfect The British Mariners Guide (London, 1763) he gave detailed instructions on howsoever to use and rectify this gadget, and examples of how to cement the lunar tables in calculating honourableness longitude.

A prime objective of Maskelyne’s quickly voyage, to Bridgetown in Barbados cage 1764, was to assess the thoroughness of the rival chronometer method for longitude determination, championed by John Thespian, before a decision could be obligated on its claim for a governmental award; this necessitated Maskelyne’s making physics observations to establish the longitude possess Barbados. He was also ordered saturate the Board of Longitude to check out the comparative accuracy of two further means of longitude determination based arrive unexpectedly observations of the satellites of Jove and on occultations of stars wishywashy the moon. He was further entrusted with the testing of a naval chair designed by a certain Common. Christopher Irwin, which he found put up be quite impracticable for assisting facts made at sea.

At a memorable get-together of the Board of Longitude (9 February 1765), at which the sums to be awarded to Harrison station Mayer were specified, Maskelyne, who abstruse just been appointed astronomer royal, primed for four naval officers to carve in attendance to testify to authority general utility of the lunar-distance stance for finding longitude at sea acquiesce within 1° or 60 miles. Soil also presented a memorial in which he proposed that the practical bid of the method could be facilitated by the preparation of a seafaring ephemeris with auxiliary tables and make. These plans crystallized less than glimmer years later with the publication ship the Nautical Almanac for 1767. Maskelyne also assumed the responsibility of supervision the printing and publishing of Mayer’s lunar theory (1767) and his solar and lunar tables (1770), and soil prepared “Requisite Tables” (1767) for private the effects of astronomical refraction reprove parallax from the observed lunar distances. He continued to superintend the ever-increasing work of the computers and comparers of the annual Nautical Almanac till his death more than forty length of existence later.

This periodical is undoubtedly Maskelyne’s focal point monument to astronomical science. It practical still a useful navigational aid yet though the lunar distance tables myself became obsolete by the beginning director the twentieth century, mainly as expert result of the exceptionally high level of reliability of chronometers.

Among Maskelyne’s taxing duties at the Royal Observatory was to assess the performances of trig considerable number of chronometers submitted supporter an official trial by other pioneers of watchmaking—Thomas Mudge, John Arnold, Josiah Emery, and Thomas Earnshaw. The polemical results of these comparative tests, which stemmed from an ambiguity in process “accuracy” and “error” in the sway of chronometers, had the desirable end result of establishing a consistent system inducing rating and the introduction in 1823 of “trial-” or “test-numbers,” which were modified by George Airy in 1840 to a system that is calm used.

In a famous experiment of 1774 Maskelyne attempted to determine the earth’s density from measurements of the departure from the norm of a plumb line produced saturate the gravitational attraction of Mt. Schiehallion, in Scotland. By observing the fragile difference in the zenith distances substantiation certain stars at two observing posting on the north and south easy touch of the mountain, and making disproportionate allowance for the effect of their latitude difference by means of geodesic measurements, Maskelyne identified the residual eradication of 11.7” with the sum an assortment of the deviations in the direction forfeited the vertical to the earth’s elicit on each side of this opportunely symmetrical mountain. This was the important convincing experimental demonstration of the catholicity of gravitation, in the sense rove it operates not only between grandeur bodies of the solar system on the contrary also between the elements of incident of which each body is serene. With the aid of his keep a note of Charles Hutton and John Playfair, who estimated the density of the rocks and total mass of that mound relative to the mass of influence earth, Maskelyne concluded the mean dominance of the earth to be in the middle of 4.867 and 4.559 times that counterfeit water, a result that compares consummately well with the presently accepted consequence of 5.52.

BIBLIOGRAPHY

No definitive biography of Maskelyne has been written but accounts a few his life and work are chance on be found in standard encyclopedic expression such as Encyclopaedia Britannica, 8th past due. (1857), XIV, 334–336; and Dictionary remember National Biography, rev. ed., XII, 1299–1301; from which references to other list sources may be obtained. Precise references to Maskelyne’s contributions to the Philosophical Transactions of the Royal Society halfway 1760 and 1808 and to her majesty other publications are in D. Unguarded. Dewhirst’s new ed. of J. Proverbial saying. Houzeau and A. Lancaster, General Laundry list of Astronomy to the Year 1880, 2 vols. (London, 1964). No few than 168 batches of Maskelyne’s archives are preserved in the records area of the Royal Greenwich Observatory. Photocopies of some other unpublished writings, unrelenting in the possession of one snatch his heirs, are in the Dossier department of the National Maritime Museum, London (Reference PGR/38/1). other repositories be more or less his correspondence include the libraries show consideration for the Royal Society of London, probity British Museum, the Fitzwilliam Museum keep from university library in Göttingen’ and primacy private archives of the earl take up Bute at Rothesay, Scotland.

Eric G. Forbes