This month we feature a remarkable 18th century clock made by self-taught astronomer and inventor Lawrence Earnshaw.
This month we feature an intriguing astronomical clock constructed in the mid-eighteenth century by Lawrence Earnshaw (1707 – 1767), an English mechanic and inventor from Cheshire, England.
About the clock
Astronomical clocks have special mechanisms and dials displaying astronomical information, such as the relative positions of the Sun, Moon, constellations, and planets.
Earnshaw’s 18th century mechanical marvel comprises two globes housed in brass plates. On the left is a ‘terrestrial’ globe displaying on its surface a map of the Earth, and on the right is a ‘celestial’ globe showing the apparent position of the stars in the sky.
Outside the three smaller dials, within the dial’s outer concentric rings, we can read the months of the year with the number of days, the days of the month, and then finally the declination (the angular distance of a point north or south of the celestial equator) of the Sun itself, and the position along the perspective of the Earth’s orbit around the Sun, also known as the ‘ecliptic’.
The clock is wound and operated by hand, with its one-second pendulum and weight hanging directly below, with space carved out of the shelves within the wooden cabinet to accommodate this.
The clock was described by a Josiah Beckwith from Leeds, in ‘The Gentleman’s Magazine’ July 1787 edition:
History of the Clock
About the Maker
Accounts of the maker of the clock, Lawrence Earnshaw describe him as an extremely knowledgeable person with particular understanding of mechanics. However, he was never recognised for his abilities during his lifetime and lived in relative poverty.
He was born in the parish of Mottram, Cheshire and at an early age was apprenticed to a clothier for seven years followed by four years’ training as a tailor. However, he subsequently gave up this career and turned to inventing, making and mending things, including clocks, violins, optical instruments and sundials as well as inventing and making tools and machines used in the mechanical production of textiles. Around 1753 he invented a machine which spun and reeled cotton in one operation. This was fourteen years before Arkwright invented the ‘Spinning Jenny’. However, he decided that his machine would harm the working classes through mechanising this hitherto manual process and he decided to destroy it.
Earnshaw made many clocks, but he is especially known for his astronomical clocks, which involved many mechanical and astronomical calculations.
The inscription on Lawrence Earnshaw's memorial monument reads:
"Lawrence Earnshaw, Mottram, died 12 May 1767, and was interred in the adjoining graveyard. A century after his decease, the admirers of his genius erected this Monument AD 1868. A self-taught genius of humble birth, his talents as an inventor anticipated by many years the discoveries of other eminent men. By his skill in geometry and his acquirements as a mechanician, he designed and constructed an astronomical clock for registering the revolution of the heavenly bodies and the flow of the tides."
Acknowledgements
Joe Harvey - student, MA Curation: Art and Business, University of Exeter
Professor Tim Naylor, University of Exeter
Duckworth, M.* The Earnshaw Clock*, Journal of the British Astronomical Association. 1969, 80, 1. 1969JBAA...80...40D (harvard.edu)
Duckworth, M. Lawrence Earnshaw - A Remarkable Clock Maker, Journal of the British Astronomical Association 1967, 1967JBAA...78...22D (harvard.edu)
Beckwith, Josiah. The Gentleman's Magazine, July 1787, pages 665 and 666, (Google Books)
University of Exeter
Room 153, Queen's Building
The Queen's Drive
Exeter EX4 4QH
