Barlow, Edward

SUBJECT AREA: Horology

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baptized 15 December 1636 near Warrington, Cheshire, England d. 1716

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English priest and mechanician who invented rack striking, repeating mechanisms for clocks and watches and, with others, patented a horizontal escapement for watches.

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Barlow was the son of Edward Booth, but he adopted the surname of his godfather, the Benedictine monk Ambrose Barlow, as a condition of his will. In 1659 he entered the English College at Lisbon, and after being ordained a priest he was sent to the English mission. There he resided at Parkhall in Lancashire, the seat of Mr Houghton, with whom he later collaborated on the horizontal escapement.

At a time when it was difficult to produce a light to examine the dial of a clock or watch at night, a mechanism that would indicate the hours and subdivisions of the hour audibly and at will was highly desirable. The count wheel, which had been used from the earliest times to control the striking of a clock, was unsuitable for this purpose as it struck the hours in sequence. If the mechanism was set off manually to determine the time, the strike would no longer correspond with the indications on the dial. In 1675 Barlow invented rack striking, where the hour struck was determined solely by the position of the hour hand. With this mechanism it was therefore possible to repeat the hour at will, without upsetting the sequence of striking. In 1687 Barlow tried to patent a method of repeating for watches, but it was rejected by James II in favour of a system produced by the watchmaker Daniel Quare and which was simpler to operate. He was successful in obtaining a patent for a horizontal escapement for watches in 1695, in collaboration with William Hough ton and Thomas Tompion. Although this escapement was little used, it can be regarded as the forerunner of the cylinder escapement that George Graham introduced c. 1725.

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Bibliography

1695 (with William Houghton and Thomas Tompion), British patent no. 344 (a horizontal escapement).

Further Reading

Dictionary of National Biography, 1885, Vol. 1, Oxford, S.V.Barlow.

Britten's Old Clocks \& Watches and Their Makers, 1982, rev. Cecil Clutton, 9th edn, London, pp. 148, 310, 313 (provides a technical description of rack striking, repeating work and the horizontal escapement).

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