Leonard Digges (scientist) | Wikipedia audio article


For Leonard Digges’s grandson, a minor poet
by the same name, see Leonard Digges (writer).Leonard Digges (c.1515 – c.1559) was a well-known
English mathematician and surveyor, credited with the invention of the theodolite, and
a great populariser of science through his writings in English on surveying, cartography,
and military engineering. His birth date is variously suggested as c.1515
or c.1520 (but certainly by 1530).Much of his work was expanded on, annotated, and published
by his son, Thomas Digges. His son followed in his footsteps and was
a pivotal player in the popularisation of Copernicus’s book De revolutionibus orbium
coelestium. Notes written by Thomas Digges in the publication
of the book Pantometria in 1570 contain descriptions of how Leonard Digges made use of a “proportional
Glass” to view distant objects and people. Some, such as astronomer and historian Colin
Ronan, claim this describes a reflecting or refracting telescope built between 1540 and
1559, but its vague description and claimed performance makes it dubious.==Biography==
Leonard Digges, born about 1515, was the only son of James Digges (born c.1473), esquire,
of Digges Court and Broome in Barham, Kent, by his second wife, Philippe Engham, the daughter
of John Engham, esquire, of Chart, Kent. James Digges had been High Sheriff of Kent
in 1510–11, and had married as his first wife Mildred Fineux, the daughter of Sir John
Fineux, Chief Justice of the King’s Bench, and Elizabeth Apuldrefield, by whom he had
an only son, John Digges, who married Mildred Scott, the daughter of Sir John Scott (d. 7 October 1533) of Scot’s Hall in Smeeth,
Kent. John Digges predeceased his father, leaving
two sons by his wife, Mildred Scott, William Digges and Francis Digges. James Digges made his last will on 20 February
1535/6 requesting burial in the north chancel of the church of Barham, ‘where my mother
and my wife do lie’, and naming as executors his second wife, Philippe; John Sackville,
esquire; his nephew, Robert Brent, gentleman; and his son, Leonard, with Sir William Hawte
as overseer. The will was proved on 24 November 1540, at
which time his second wife, Philippe, was still living.Leonard Digges was the grandson
of John Digges, esquire, of Digges Court and Broome, High Sheriff of Kent in 1495-6, and
his wife Joan Clifton, the daughter and co-heiress of Sir Gervase Clifton of Clifton, Nottinghamshire,
London, and Brabourne, Kent, by his first wife, Isabel Herbert, daughter of Vincent
Herbert, esquire. Leonard Digges’ aunt, Isabel Digges, the daughter
of John Digges and Joan Clifton, married Richard Sackville (d. 28 July 1524), esquire, and was the mother
of John Sackville.In 1542 Digges, in company with three other gentlemen, visited the castle
of Guînes, ‘where they impressed their host through debate and demonstration of their
skills in geometry, navigation, measurement, and artillery’.In January 1554 Digges took
part in an unsuccessful rebellion led by the Protestant Sir Thomas Wyatt, who opposed the
projected marriage between Philip II of Spain and England’s new Catholic Queen, Mary I.
Digges was convicted of high treason, attainted, and condemned to death. His life was pardoned on 1 April 1554, but
according to Johnston ‘his lands and goods, which had been seized after his attainder,
continued to be held subject to payment of recognizances to the crown’. In February 1555 Digges was fined 400 marks. After being paid off in instalments, the fine
was discharged on 7 May 1558. The date of Digges’ death is unknown; he is
thought to have died about 1559: From Thomas’s autobiographical comments in
a legal dispute of the 1590s it can be inferred that Leonard died about 1559, shortly after
he had resumed possession of his confiscated lands.===Marriage and issue===
Digges married Bridget Wilford, the daughter of Thomas Wilford, esquire, of Hartridge in
Cranbrook, Kent, by his first wife, Elizabeth Culpeper, the daughter of Walter Culpeper,
esquire, by whom he had three sons and three daughters:
Thomas Digges, esquire. James Digges. Daniel Digges. Mary Digges, who married a husband surnamed
Barber. Anne Digges, who married William Digges. Sarah Digges, who married firstly a husband
surnamed Martin, and secondly John Weston.==Works==
The first publication of many by Leonard Digges was A General Prognostication published in
1553, which became a best-seller as it contained a perpetual calendar, collections of weather
lore and a wealth of astronomical material, until then largely only obtainable through
books published in Latin or Greek. It was revised in 1555 (the earliest surviving
edition) and again in 1556 with the title A Prognostication everlasting. Subsequent editions reprint the text from
1556; editions from 1576 and later include additional material by his son.===Telescope===
There are claims Leonard Digges independently invented the reflecting telescope, and/or
the refracting telescope as part of his need to see accurately over long distances during
his surveying works. In the preface to the 1591 Pantometria, (a
book on measurement, partially based on his father’s notes and observations) Leonard’s
son Thomas lauded his father’s accomplishments. Some of the praise of the son for the father
appears to be extravagant exaggeration, while other claims appear more credible. On the fifth page of the preface, Thomas Digges
provides a remarkable account of his father’s accomplishments: [H]is divine mind aided with this science
of Geometrical mensurations, found out the quantities, distances, courses, and strange
intricate miraculous motions of these resplendent heavenly Globes of Sun, Moon, Planets and
Stares fixed, leaving the rules and precepts thereof to his posterity. Archimedes also (as some suppose) with a glass
framed by revolution of a section Parabolicall, fired the Roman navy in the sea coming to
the siege of Syracuse. But to leave these celestial causes and things
done of antiquity long ago, my father by his continual painful [painstaking] practices,
assisted with demonstrations Mathematical, was able, and sundry times hath by proportional
Glasses duly situate in convenient angles, not only discovered things far off, read letters,
numbered pieces of money with the very coin and superscription thereof, cast by some of
his friends of purpose upon downs in open fields, but also seven miles off declared
what hath been done at that instant in private places. The writings left by Digges’ colleague William
Bourne contain further detail on the experiments with lenses and mirrors conducted by Leonard
Digges and his son. It is these details which led some researchers,
most notably Colin Ronan, to claim that Leonard Digges invented a functioning telescope sometime
between 1540 and 1559. The description seemed to suggest that Digges
created a rudimentary instrument incorporating lenses and a concave mirror, in a manner rather
different from a modern reflecting telescope. However, the construction of lenses to the
required optical precision would have been very difficult in the 16th century, and the
construction of an adequate mirror would have been much harder still. It is doubtful that Digges built a successful
instrument, and the optical performance required to see the details of coins lying about in
fields, or private activities seven miles away was far beyond the technology of the
time.==Notes

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