Reference numberMS/125
TitlePapers on desalination by Zachariah [Zachary] Williams
CreatorWILLIAMS, Zachariah (Zachary) 1668-1755
DescriptionProposal for the revealing a secret of a machine invented by Williams to be used at sea for making salt-water fresh and drinkable. Together with the inventor's letter to the Lords of the Admiralty on the subject.

Includes an original cover endorsed: 'Appendix no.3. Papers relating to the proposal of Zach: Williams for the Longitude'; and in pencil: 'Making salt water fresh and drinkable'
Extent7 items [1 box], MS Box, Small
Physical descriptionPaper, unbound
Access statusOpen
Administrative historyExperimental philosopher, born in Rosemarket, Pembrokeshire. Educted in medicine, and served as a medical practitioner in south Wales until moving to London in 1726 or 1727. He developed a method for ascertaining longitude using a theoretically derived table of the earth's magnetic variation (declination) in which the angle between geographic north and the direction indicated by the compass needle was calculated for different points of the globe. John Rowley, the instrument maker noted for his redesigned orrery was his friend, and he met other influential figures such as Edmond Halley, J T Desaguliers and William Whiston, and his globe was demonstrated before the Royal Society.

Williams scheme for ascertaining longitude was supported by a group of gentlemen subscribers, and on being submitted to the Admiralty it was referred to Sir Isaac Newton, who declined on account of his age, and was then sent to Samuel Molyneux ( later accused by Williams for stealing his plan). In spite of this backing his proposal was rejected. Sir Robert Walpole nominated him for Charterhouse, to which he was admitted as a ' poor brother pensioner' on 29 September 1729, and subsequently ejected on 23 May 1748. Williams was also friendly with electrician Stephen Gray, and they exchanged information on magnetism and electricity. After leaving Charterhouse, he was in corespondence with Samuel Johnson, who supported him and Anna his daughter. Johnson compiled an account of Williams's theories on ascertining longitude at sea magnetically and published it in 1755 under William's name, together with an Italian translation by Giuseppe Barretti in order to give William's views a foregn circulation. The Admiralty submitted William's proposal to James Bradley, Astronomer Royal, who also examined his magnetic globe and tables, but concluded they were not sufficiently reliable to use at sea.

Because of the way many longitude proposals were mocked, Williams was marginalized by his contemporaries, and his work had little direct impact on projects to map terrestrial magnetism, though Johnson remained a loyal patron. Williams died on 12 July 1755.

One of William's inventions was a device for desalinating sea water to make it drinkable, and he attempted to use his connections to promote his idea. This correspondence was part of his attempt to get the Admiralty to take it up in 1753.
Related materialDM.2.155; MM.10.15; MM.10.16;
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