 For the Worshipful Company of Saddlers he painted a full-length portrait of Frederick, Prince of Wales (1736, destroyed 1940), which he engraved in mezzotint and published in 1741.With his silent partner, a London merchant Edward Heylyn, he took out a patent on kaolin to be imported from the English colony of Virginia in November 1745, and became manager of the Bow factory from its obscure beginnings in the 1740s.He retired to Wales in 1759 for the sake of his lungs, but soon returned to London and resumed his occupation as an engraver, publishing the series of life-size fancy portraits in mezzotint, by which he is most remembered.