The surface is first ground either by sand-blast or the ordinary method, and is then covered with a sort of varnish. On being dried either in the sun or by artificial heat, the varnish contracts strongly, taking with it the particles of glass to which it adheres; and as the contraction takes places along definite lines, the pattern given by the removal of the particles of glass resembles very closely the branching crystals of frostwork. A single coat gives a small, delicate effect, while a thick film, formed by putting on 2, 3 or more coats, contracts so strongly as to produce a large and bold design. By using colored glass, a pattern in half-tint may be made on the colored ground, and after decorating white glass, the back may be silvered or gilded.
Engraving, Matting, And Frosting.
To Render Window Panes Opaque.
II.—Paint the panes with a solution of
| Dextrin | 200 parts by weight |
| Zinc vitriol | 800 parts by weight |
| Bitter salt | 300 parts by weight |
| In water | 2,000 parts by weight |
III.—For deadening panes already set in frames the following is suitable: Dissolve 1 part of wax in 10 parts of oil of turpentine, adding 1 part of varnish and 1 part of siccative. With this mixture coat the panes on the outside and dab, while still wet, with a pad of cotton wadding. If desired small quantities of Paris blue, madder lake, etc., may be added to the wax solution.
IV.—For deadening window panes in factories and workshops: To beeswax dissolved in oil of turpentine, add some dryer and varnish to obtain a quicker drying and hardening. After the window pane has been coated with this mixture on the outside, it is dabbed uniformly with a pad of wadding. The wax may be tinted with glazing colors.
Frosted Mirrors.
II.—The following mixture, when applied to a mirror and left to dry, will form in many shapes, all radiating from a focus, this focus forming anywhere on the glass, and when all dry tends to form a most pleasing object to the eye.
| Sour ale | 4 ounces |
| Magnesium sulphate | 1 ounce |