Ball clay used in the preparation of white enamel body may have a composition of Cornish stone, 40 parts; Cornish clay, 10; and blue clay, 20. Or Cornish stone, 80 parts; Cornish clay, 20; blue clay, 40; and flint, 20. Or Cornish stone, 100 parts; Cornish clay, 20; blue clay, 18; and flint, 40. Or Cornish stone, 30 parts; Cornish clay, 10; blue clay, 17; and flint, 8. The colour can be rendered bluish-white by the addition of a little cobalt blue. The non-fusible materials added to the glaze are barytes, bone ash, and oxide of tin; the latter is put into nearly all enamel glazes. The clays are mixed with excess of water, passed through a fine sieve, and then boiled down to a paste. Here are recipes for white glazes. White glass, 100 parts: white sand, 50; salt. 40; litharge, 120; and oxide of tin, 60. Or lead and tin ashes, 44 parts; sand, 44; soda, 2; common salt, 8; and red-lead, 8.