Five parts of the ordinary luminous powder prepared from oyster-shells as previously directed; ten of fluor-spar, cryolite, or other similar fluoride; one of barium borate; powdered, mixed, made into a cream with water, painted on the glass or stone article, dried, and fired in the usual way for enamels. If the article contains an oxide of iron, lead, or other metal, it must be first glazed with ground felspar, silica, lime phosphate, or clay, to keep the sulphur of the sulphide from combining with the metal. The result is an enameled luminous article.