A fine copper red was obtained from sand, 10 parts; potash, 3 parts; lime, 1.2 parts; soda, 0.25 parts; sulphide of copper, 7.5 parts; sulphide of sodium, 10.5 parts; borax, 9.5 parts.
Attempts to color with sulphides of antimony and bismuth failed. But the addition of 7 per cent of sulphide of nickel to an ordinary batch gave a glass of fine amethyst color.
Coloring Electric-light Bulbs And Globes.
Rose-tint Glass.
Cutting, Drilling, Grinding, And Shaping Glass:
To Cut Glass.
The same principle may be employed to cut bottles into vases, and to form all sorts of pretty things, such as jewelry boxes, picture panes, trays, small tablets, windows for a doll house, etc.
II.—Scratch the glass around the shape you desire with the corner of a file or graver; then, having bent a piece of wire into the same shape, heat it red hot and lay it upon the scratch and sink the glass into cold water just deep enough for the water to come almost on a level with its upper surface. It will rarely fail to break perfectly true.