Production of colored glasses

Claim 1

THE METHOD OF PRODUCING COLORED OPAL GLASS RANGING IN COLORATION FROM OPAQUE LIGHT IVORY TO OPAQUE DARK BROWN COMPRISING THE STEPS OF PROVIDING AN OPAL GLASS BATCH CONSISTING ESSENTIALLY OF THE FOLLOWING CONSTITUENTS IN CALCULATED PERCENTAGE BY WEIGHT: 60-75% SIO2, 0-2% B2O3, 4-9% AL2O3, 10-18% NA2O, 0-10% K2O, 0-11% CAO, 0-2% MGO, 4-8% F2, 0-2% ZNO, 0-0.10% FE2O3, 0.0043-0.183% SULPHUR, AND 0.0057-0.280% GLASS-FORMING ELEMENTAL METAL IN POWER FROM SELECTED FROM THE GROUP CONSISTING OF SILICON AND ALUMINUM, SAID SULFUR BEING INCLUDED IN SAID BATCH IN READILY REDUCIBLE FORM, MELTING THE SAID BATCH CONSTITUENTS BY HEAT-REACTION IN A MELTING CHAMBER, EFFECTING A REDUCTION OF AT LEAST A PORTION OF SAID SULFUR TO METALLIC SULFIDES "IN SITU" WITHIN SAID MELTING CHAMBER TO EFFECT UNIFORM COLORATION OF THE MOLTEN GLASS, SAID ELEMENTAL METAL BECOMING OXIDIZED AND PRODUCING NO COLORATION, AND CONVEYING THE SAID MOLTEN GLASS TO A POINT OF USE.