William Cookworthy (12 April 1705 – 17 October 1780) was an English chemist and a member of the Religious Society of Friends (Quaker) from Kingsbridge, Devon.Later Cookworthy discovered the Writings of Emanuel Swedenborg and was an significant advocate of them. He discovered china clay in Cornwall and devised a way of making porcelain, which previously had needed to be imported from China. He was also an associate of John Smeaton, who lodged at his house when he was engaged in building the third Eddystone Lighthouse (1756-1759). Cookworthy helped Smeaton with the development of hydraulic lime, which was essential to the successful building of the lighthouse. In 1768 he founded a works at Plymouth for the production of Plymouth Porcelain. April 12 is the 102nd day of the year in the Gregorian calendar (103rd in leap years). ... // Events Construction begins on Blenheim Palace, in Oxfordshire, England. ... October 17 is the 290th day of the year (291st in leap years) in the Gregorian calendar. ... 1780 was a leap year starting on Saturday (see link for calendar). ... A chemist pours from a Florence flask. ... The Religious Society of Friends (commonly known as Quakers) began in England in the 17th century by people who were dissatisfied with the existing denominations and sects of Christianity. ... For the Kingsbridge in New York City, see Kingsbridge, Bronx, New York. ... Devon is a large county in South West England, bordered by Cornwall to the west, Dorset and Somerset to the east. ... Kaolin Kaolinite (Aluminium Silicate Hydroxide) Kaolinite is a clay mineral with the chemical composition Al2Si2O5(OH)4. ... Fine China redirects here. ... Portrait of John Smeaton, with the Eddystone Lighthouse in the background. ... The Eddystone Lighthouse is situated some 9 miles (15km) South West of Rame Head Cornwall, England on the treacherous Eddystone Rocks 50°10. ... 1756 was a leap year starting on Thursday (see link for calendar). ... 1759 was a common year starting on Monday (see link for calendar). ... Hydraulic lime is a variety of slaked lime used to make mortar. ... Plymouth is a city in the southwest of England, or alternatively the Westcountry, and is situated within the traditional county of Devon. ... Plymouth porcelain was a type of porcelain developed in England in the 18th century. ...