GARNET-COLOUR. To give this colour to glass, the workmen take equal quantities of crystal and Rochetta fritt; and to every hundred weight of this mixture they add a pound of manganese, and a pound of prepared zaffre: these are to be powdered separately, then mixed and added by degrees to the fritt while in the furnace: great care is to be taken to mix the manganese and zaffre very perfectly; and when the matter has stood 24 hours in fusion, it may be worked.