John Theophilus Desaguliers

John Desaguliers
John Theophilus Desaguliers (1683-1744)
Born	(1683-03-12)12 March 1683 La Rochelle, France
Died	29 February 1744(1744-02-29) (aged 60) Covent Garden, London, England
Residence	England
Nationality	French, English
Fields	Natural philosophy and engineering
Institutions	University of Oxford
Alma mater	Christ Church, Oxford
Academic advisors	John Keill
Notable students	Stephen Demainbray Willem 's Gravesande Stephen Gray
Known for	Planetarium, portraits, improvement in steam engine
Influences	Isaac Newton
Notable awards	Copley Medal

John Theophilus Desaguliers (/deɪzæɡjuːlɪˈeɪ/; French: Jean Théophile Désaguliers, [dezaɡylje]; 12 March 1683 – 29 February 1744) was a French-born British natural philosopher who was a member of the Royal Society of London beginning 29 July 1714. He was presented with the Royal Society's highest honour, the Copley Medal, in 1734, 1736 and 1741, with the 1741 award being for his discovery of the properties of electricity.^[1][2] He studied at Oxford, became experimental assistant to Sir Isaac Newton, and later popularized Newtonian theories and their practical applications. He has been credited as the inventor of the planetarium, on the basis of some plans he published.

Biography

Born in La Rochelle, Desaguliers was an immigrant to England from France. He was born into a Huguenot (Protestant) family and fled to England not at the age of 11 (1694) but as an infant (1683) to escape the consequences of the Revocation of the Edict of Nantes. He was educated at Christ Church, Oxford, and succeeded Dr John Keill in reading lectures on experimental philosophy at Hart Hall. He was the first who introduced the reading of lectures in London, where he had for his auditors not only the learned and the great, but also George I and George II and the royal family. In 1714, he was chosen a member of the Royal Society, to whose Transactions he communicated some valuable papers. In 1718, he completed his degrees at Oxford as bachelor and doctor of laws. Desaguliers' reputation as a scientist was sealed not only by his three awards from the Royal Society, but also by publication of a two volume work entitled A Course of Experimental Philosophy. Publication of the first volume coincided with the year he first received the Copley Medal (1734), while the second volume's publication came 10 years later in 1744, the year of his death. The first volume concerns theoretical and practical mechanics with an explanation of the basics of Newtonian physics. The second volume contains material oriented toward practical application of scientific findings.^[3] Following upon the work of Stephen Gray, he introduced the term "conductor" for things such as metals which conduct electricity, to which an electrified glass tube conveyed the electric charge.^[4]

An inventor as well as a scientist, Desaguliers improved upon the steam engine design of Thomas Savery through the addition of a safety valve. He also designed methods for heating liquid boilers with steam rather than fire, presumably increasing their safety significantly.^[5]

Additionally, Desaguliers was a Freemason, elected as the third Grand Master in 1719, Deputy Grand Master in 1723 and 1725 of the newly formed Premier Grand Lodge of England.

Desaguliers employed the strong-man Thomas Topham as a bodyguard and had Topham perform at meetings of the Royal Society.^[6]

Role as priest and hydraulic engineer at Cannons

Desaguliers was also a priest in the Church of England. Through the patronage of James Brydges, 1st Duke of Chandos, he was nominated in 1714 to the living of St Lawrence's church, Little Stanmore (sometimes called Stanmore Parva, or Whitchurch), then in Middlesex. His duties as a parish priest were combined with being chaplain to the Duke, as St Lawrence's church was at the edge of the duke's estate, Canons Park. The church was rebuilt in the baroque style in 1715. As the chapel at Cannons was not completed until 1720, the church was the location of first performances of the so-called Chandos Anthems by George Frideric Handel, who was in 1717/18, like Desaguliers, a member of the Duke's household.

The Canons estate benefited from Desaguliers' scientific expertise which was applied to the elaborate water garden there. He was also technical adviser to an enterprise in which Chandos had invested, the York Buildings Company, which used steam-power to extract water from the Thames. In 1718 Desaguliers dedicated to the Duke his translation of Edme Mariotte's treatise on the motion of water.^[7] It is perhaps no coincidence that in the summer of 1718 the composer Handel, Desaguliers' colleague at Cannons, composed his opera Acis and Galatea for performance there. In this work the hero Acis is turned into a fountain, and since, by tradition, the work was first performed outside on the terraces overlooking the garden, a connection with Desaguliers' new water works seems probable.^[8]

Desaguliers appears to have been distracted from his parochial duties by his other interests, and the Duke complained that there were unreasonable delays in burying the dead. However, despite falling out with his patron, Desaguliers retained the living until his death.

Portraits

There are at least three surviving portraits of Desaguliers dating to 1725 (42 years of age), all held by the National Portrait Gallery in London and available for on-line viewing.There is also a portrait by Desrochers^[9]

Personal life

On 14 October 1712 he married Joanna Pudsey, daughter of William and Anne Pudsey of Kidlington, near Oxford. They had four sons and three daughters, for most of whom they acquired aristocratic godparents, but only two children survived beyond infancy: John Theophilus (1718–1751) graduated from Oxford, became a clergyman, and died childless, while Thomas Desaguliers (1721–1780) led a distinguished scientific military career. On 1 April 1748 he became chief firemaster at the Arsenal, Woolwich, a post which he held until the end of his life, and seems to have been the first to be employed by the English army to apply scientific principles to the production of cannon and the powers of gunnery.^[10] It was Thomas Desaguliers who designed and supervised the fireworks for the first performance of Handel's Music for the Royal Fireworks in Green Park.^[11]

Decline

Desaguliers had long suffered from gout every winter, and died after several months of severe illness at his home in the Bedford Coffee House, Covent Garden, London, on 29 February 1744; he was buried on 6 March in the Savoy Chapel, Savoy Street, London. The following lines of the poet James Cawthorn depict the indigence and neglect into which he fell in his old age:^[12]

How poor neglected Desaguiliers fell!
How he who taught two gracious kings to view
All Boyle ennobled, and all Bacon knew,
Died In a cell, without a friend to save,
Without a guinea, and without a grave.

See also

• Stephen Gray

References

Further reading

• Baker, C. H. Collins, and BaKer, Muriel (1949) James Brydges First Duke of Chandos Oxford: Clarendon Press
• Carpenter, A, (2011), John Theophilus Desaguliers: A Natural Philosopher, Engineer and Freemason in Newtonian England, (London: Contnuum), ISBN 1-4411-2778-X; ISBN 978-1-4411-2778-5
• Carpenter, A. and Pink, A. (2006) The letters of James Brydges Earl of Carnarvon and later Duke of Chandos (1674–1744) to John Theophilus Desaguliers (1683–1744). An ongoing web project: UCL and Loughborough universities, UK
• Mackey, Albert G. (1966), An Encyclopedia of Freemasonry, reprint edition, (Chicago:, The Masonic History Company).

External links

• Masonic biography
• Scientific biography
• British Journal of Psychology
• "Desaguliers, John Theophilus (DSGS726JT)". A Cambridge Alumni Database. University of Cambridge.