Re‐creation of the 1744 Heylyn and Frye ceramic patent wares using Cherokee clay: Implications for raw materials, kiln conditions, and the earliest English porcelain production

Porcelain wares have been produced following the directions contained in the Heylyn and Frye patent of 1744, using Cherokee clay and a lime‐alkali glass frit. The wares were fired to the bisque (˜ 950°C), glazed using a clay‐glass mixture, and then fired to a “heat‐work” level of Orton cone 9–90° deflection at 150°C per hour (1279°C). Modal mineralogy comprises Caplagioclase and two glass phases, one relict frit and the other a melt phase. The bulk chemistry of the body comprises 64.3 wt % SiO 2 , 21.7 wt % Al 2 O 3 , and 5.6 wt % CaO. Molecular ratios are SiO 2 :Al 2 O 3 5.0 and SiO 2 :CaO 10.7. It is concluded that the patent, whose significance has been questioned over many years, was a practical working recipe, that close comparison may be made with porcelains of the “A”‐marked group, and that the patent represents a remarkable landmark in English ceramic history. © 2004 Wiley Periodicals, Inc.