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John Arnold

Infobox Person
name = John Arnold


image_size = 160px
caption =
birth_date = 1736
birth_place = Bodmin, Cornwall, England
death_date = 11 August 1799
death_place = Eltham, Kent, England
occupation = Watchmaker
spouse =
parents =
children = John Roger

:"This article is about the watchmaker and inventor, and his son. For others of the same name, see John Arnold (disambiguation)."

John Arnold (born 1736 in Bodmin, Cornwall - died 1799 in London) was an English watchmaker who developed and patented escapement and balance spring designs. He is known to have lived for a period at Well Hall House in Eltham, which was then a civil parish of Kent. In 1764, Arnold constructed what was then the smallest repeating watch, which was set in a ring and given to George III. [cite book | author=Gould, Rupert T. | pages=106 | title=The Marine Chronometer. Its History and Development | location=London | publisher=J. D. Potter | year=1923 | id=ISBN 0-907462-05-7]

He then turned his attention to the production of ever more precise chronometers. One of these travelled with the explorer James Cook during his second voyage to the southern Pacific Ocean in 1772–1775. Arnold and his rival Thomas Earnshaw were the first to produce chronometers in significant quantities. Arnold is known for refinement of the chronometer escapement and balance spring. In 1776 he obtained a patent on the helical balance spring, though he was not in fact the first to use that shape; it was originally used by Robert Hooke in 1664. [cite book | author=Gould, Rupert T. | pages=105-115 | title=The Marine Chronometer. Its History and Development | location=London | publisher=J. D. Potter | year=1923 | id=ISBN 0-907462-05-7] The helical shape is an effective one for precision timekeepers, because it is easier to make such a spring isochronous, i.e., having a period which remains the same whether the balance swings through a large or a small arc.

Arnold set up a small factory in Chigwell, Essex for the production of chronometers and in 1788 produced the first pocket chronometer. This watch, "No. 1/36", greatly impressed the Astronomer Royal Nevil Maskelyne and was the first watch Arnold deemed worthy of the description "chronometer".

John Roger Arnold

Arnold's son John Roger Arnold was born in 1769 and served an apprenticeship with both his father and the eminent French watchmaker Abraham Louis Breguet. He became Master of the Worshipful Company of Clockmakers in 1817. From 1787 he and his father founded the company Arnold & Son, which, after his father's death in 1799, John Roger continued the business taking into partnership John Dent between 1830 and 1840. After his death in 1843 the company was bought by Charles Frodsham.

The name "Arnold & Son" is now used by a Swiss watch company, which has no connection to the firm founded by John Arnold.

ee also

*Larcum Kendall
*Thomas Earnshaw

References

Persondata
NAME= Arnold, John
ALTERNATIVE NAMES=
SHORT DESCRIPTION= Watchmaker
DATE OF BIRTH= 1736
PLACE OF BIRTH= Bodmin, Cornwall, England
DATE OF DEATH= 11 August 1799
PLACE OF DEATH= Eltham, Kent, England

Источник: John Arnold