COOKWORTHY, WILLIAM ( , English potter, famous for his discovery of china-clay and china-stone in Corn wall, and as the first manufacturer from English materials of a porcelain similar to the Chinese, was born at Kingsbridge, Devon, of Quaker parents. At 14 he was apprenticed to a London apothecary named Bevans, and afterwards carried on business at Plymouth with his master, under the title of Bevans & Cook worthy. The manufacture of porcelain was at the time attracting great attention in England, and while the factories at Bow, Chel sea, Worcester and Derby were introducing the artificial glassy porcelain, Cookworthy spent many years in searching for English materials similar to those used by the Chinese. From 1745 on wards he travelled over the greater portion of Cornwall and Devon in search of these minerals until he located them near to St. , Austell. With some financial assistance from Mr. Thomas Pitt of Boconnoc he established the Plymouth China Factory at least as early as 1768. But Cookworthy is remembered for his dis covery of those supplies of clay and rocks which form the founda tion of English porcelain and fine earthenware (see CERAMICS).