Maskelyne

[Daniel O'Hara]

For those currently interested in Nevil Maskelyne, I thought his biography
might be of interest. It comes from the O.U.P. National Dictionary of
Biography.

I would also post both Mason and Dixon`s biographies, but I have a vague
memory of someone already having done so. If I`m wrong, please tell me,
and I`ll post `em.

Dan O`Hara




Maskelyne, Nevil 1732-1811, astronomer royal, was the third 
son of Edmund Maskelyne of Purton in Wiltshire, by his wife 
Elizabeth Booth, and was born in London on 6 Oct. 1732. From 
Westminster School he entered in 1749 Catharine Hall, 
Cambridge, but migrated to Trinity College, whence he 
graduated in 1754 as seventh wrangler, taking degrees of M.A., 
B.D., and D.D. successively in 1757, 1768, and 1777. He was 
elected a fellow of his college in 1757, and admitted to the Royal 
Society in 1758. Having been ordained to the curacy of Barnet 
in Hertfordshire in 1755, he was presented by his nephew, Lord 
Clive, in 1775 to the living of Shrawardine in Shropshire, and by 
his college in 1782 to the rectory of North Runcton, Norfolk. 
The solar eclipse of 25 July made an astronomer of him, as it did 
of Lalande and Messier; he studied mathematics assiduously, 
and about 1755 established close relations with Bradley. He 
learned his methods, and assisted in preparing his table of 
refractions, first published by Maskelyne in the ‘Nautical 
Almanac’ for 1767, the rule upon which it was founded having 
been already communicated to the Royal Society (Phil. Trans. 
liv. 265). Through Bradley's influence he was sent by the Royal 
Society to observe the transit of Venus of 6 June 1761, in the 
island of St. Helena. He proposed besides to determine the 
parallaxes of Sirius and the moon (ib. li. 889, lii. 21), but met 
disappointment everywhere. The transit was concealed by 
clouds; a defective mode of suspension rendered his 
zenith-sector practically useless (ib. liv. 348). An improvement on 
this point, however, which he was thus led to devise, was soon 
after universally adopted; and during a stay in the island of ten 
months he kept tidal records, and determined the altered rate of 
one of Shelton's clocks (ib. pp. 441, 586). On the voyage out and 
home he experimented in taking longitudes by lunar distances, 
and published on his return ‘The British Mariner's Guide,’ 
London, 1763, containing easy precepts for this method, which 
he was the means of introducing into navigation. Deputed by 
the board of longitude in 1763 to try Harrison's fourth 
time-keeper (Observatory, No. 173, p. 122), he went out to 
Barbados as chaplain to her majesty's ship Louisa, 
accompanied by Mr. Charles Green. His astronomical 
observations there were presented to the Royal Society on 20 
Dec. 1764 (Phil. Trans. liv. 389).
Maskelyne succeeded Nathaniel Bliss [q.v.] as astronomer 
royal on 26 Feb. 1765, and promptly obtained the establishment 
of the ‘Nautical Almanac.’ The first number¾that for 1767¾was 
issued in 1766, and he continued for forty-five years to 
superintend its publication. Of the ‘Tables requisite to be used 
with the Nautical Ephemeris,’ compiled by him in 1766 for the 
convenience of seamen, ten thousand copies were at once sold, 
and they were reprinted in 1781 and 1802. Maskelyne's 
administration of the Royal Observatory lasted forty-six years, 
and was marked by several improvements. The observations 
made were, on his appointment, first declared to be public 
property, and he procured from the Royal Society a special fund 
for printing them. They appeared accordingly in four folio 
volumes, 1776-1811, and were at once made use of abroad, 
Delambre's solar and Burg's lunar tables being founded upon 
them in 1806. They numbered about ninety thousand, yet 
Maskelyne had but one assistant. Their scope was limited to 
the sun, moon, planets, and thirty-six fundamental stars, formed 
into a reference catalogue (for 1790) of careful accuracy. The 
proper motions assigned to them were employed in Herschel's 
second determination of the solar translation (ib. xcv. 233). 
Maskelyne perfected in 1772 the method of transit-observation 
by noting, in tenths of a second, the passages of stars over the 
five vertical wires of his telescope. He obviated effects of 
parallax by using a movable eyepiece. In 1772 he had achromatic 
lenses fitted to Bradley's instruments, and he procured about 
the same time a forty-six inch telescope, with triple object-glass 
by Dollond. The value of his later observations was impaired by 
the growing deformation of Bird's quadrant; and a mural circle, 
six feet in diameter, which he ordered from Troughton, was only 
mounted after his death.
Maskelyne published in the ‘Nautical Almanac’ for 1769 
‘Instructions relative to the Observation of the ensuing Transit 
of Venus,’ and observed the phenomenon himself on 3 June at 
Greenwich with a two-foot Short's reflector (ib. lviii. 233). From 
observations of it made at Wardhus and Otaheite he deduced a 
solar parallax of 8²×723 (VINCE, Astronomy, i. 398, 1797). He 
discussed the geodetical data furnished by Charles Mason 
(1730-1787) [q.v.] and Dixon from Maryland (Phil. Trans. lviii. 
323), explained a method of making differential measures in 
declination and right ascension with Dollond's divided 
object-glass micrometer (ib. lxi. 536), and facilitated the use of 
Hadley's quadrant (ib. p. 99). His invention of the prismatic 
micrometer (ib. lxvii. 799) had been in part anticipated by the 
Abbé Rochon. The discharge of his onerous task of testing 
timepieces exposed him to unfair attacks, especially from 
Mudge and Harrison, against which he defended himself with 
dignity. In 1772 he proposed to the Royal Society a mode of 
determining the attraction of mountains by deviations of the 
plumb-line (ib. lv. 495), and Schiehallion in Perthshire was fixed 
upon as the subject of experiments, skilfully conducted by 
Maskelyne from June to October 1774. Their upshot was to give 
11²×6 as the sum of contrary deflections east and west of the hill, 
whence Hutton deduced for the earth a mean density of 4×5 (ib. 
lxviii. 782). The Copley medal was in 1775 awarded to Maskelyne 
for his ‘curious and laborious observations on the attraction of 
mountains.’
In the dissensions of the Royal Society in 1784 Maskelyne 
strongly supported Dr. Charles Hutton [q.v.] against the 
president, Sir Joseph Banks. He advertised astronomers in 1786 
of the vainly expected return of the comet of 1532 and 1661 (ib. 
lxxvi. 426), and discussed in 1787 the relative latitude and 
longitude of the observatories of Greenwich and Paris (ib. lxxvii. 
151). Always attentive to the needs of nautical astronomy, he 
directed Mason's correction of Mayer's ‘Lunar Tables,’ and 
edited the completed work in 1787. His essay on the ‘Equation 
of Time’ (ib. liv. 336) was translated in Bernouilli's ‘Recueil pour 
les astronomes’ (t. i. 1771); his observations of the transit of 
1769 were communicated to the American Philosophical Society 
at Philadelphia in 1770 (Trans. i. 100, 2nd edit. 1789); he edited in 
1792 Taylor's ‘Tables of Logarithms,’ and in 1806 Earnshaw's 
‘Explanations of Time-keepers.’
Maskelyne was elected in 1802 one of eight foreign members 
of the French Institute. Indefatigable in the duties of his office, 
he died at the observatory on 9 Feb. 1811, aged 79. He married 
about 1785 Sophia, daughter and co-heir of John Pate Rose of 
Cotterstock, Northamptonshire, sister of Lætitia, wife of the 
Rev. Sir George Booth, Bart. Their only child, Margaret (b. 1786), 
married in 1819 Anthony Mervyn Story, to whom she brought 
the family estates in Wiltshire, inherited by her father. She 
showed much ability; she died in 1858. Her son Nevil 
Story-Maskelyne (b. 1823) was professor of mineralogy at Oxford 
(1856-95). Maskelyne was of a mild and genial temper and 
estimable character. Herschel's remark, ‘That is a devil of a 
fellow!’ after their first interview in 1782, was probably meant as 
a compliment (Memoirs of Caroline Herschel, p. 41). His sister 
Margaret, Lady Clive, survived him until 1817. A portrait of him 
by Vanderburgh is in the possession of the Royal Society. His 
manuscripts were after his death consigned to the care of 
Samuel Vince, F.R.S., but no publication resulted.

 Sources

Gent. Mag. 1811 pt. i. pp. 197, 672, 1778 p. 320; Welch's 
Alumni Westmonasterienses, p. 332; Chalmers's Biog. Dict.; 
Knight's Gallery of Portraits, vi. 20, with engraving by Scriven 
from Vanderburgh's picture, A. De Morgan; European Mag. 
xlvii. 407, with portrait; Hutton's Math. Dict. 1815; 
Cunningham's Lives of Eminent Englishmen, viii. 170; 
Delambre's Éloge, Mémoires de l'Institut, t. xii. p. lix; Delambre's 
Histoire de l'Astronomie au xviiie Siècle, p. 623; Mémoires 
couronnés par l'Acad. de Bruxelles, xxiii. 63, 1873 (Mailly); 
André et Rayet's l'Astronomie Pratique, i. 27; Bradley's 
Miscellaneous Works, p. lxxxv (Rigaud); Weale's London in 
1851, p. 637 (R. Main); Grant's Hist. of Physical Astronomy, pp. 
158, 429, 488; Clerke's Popular Hist. of Astronomy, p. 35, 2nd 
edit.; Mädler's Geschichte der Himmelskunde; Wolf's Gesch. 
der Astronomie; Montucla's Hist. des Mathématiques, iv. 313; 
Lalande's Bibl. Astr. p. 537; Poggendorff's Biog. Lit. 
Handwörterbuch; Watt's Bibl. Brit.; Observatory, v. 198, 233 
(W. T. Lynn); Weld's Cat. of Portraits, p. 48.

 Contributor

A. M. C.
PUBLISHED  1893