Explanatory notes
… treatment of oxides (of antimony, silver, arsenic, copper, chromium, cobalt, etc.) or salts (fluorides, phosphates, … kaolin, alkalies, sodium carbonate, alkaline-earth metal compounds, lead oxide, boric acid, etc.) giving a smooth … matt or glossy, by vitrification under heat. In most cases some of the constituents have been fused together in a …