Diaphanie. This beautiful art is so simple in its elements that it will not take much space to initiate the reader into its mysteries. The principal purposes to which it is applicable are for the decoration of hall windows, churches, lamp-shades, stair-cases, hand-screens, windows, and window-blinds, Chinese lanterns, and conservatories ; but it is equally available for every purpose in which the combination of transparency and ornament enter. Although the chief features of this art are the decoration of glass to the resemblance of stained windows and painted transparencies, it may be used for the adornment of window-blinds, etc, upon muslin or silk.

The materials are glass, muslin or silk, a roller, brushes, designs, one bottle of clearing liquid, prepared gum and a bottle of washable varnish.

Be sure that the glass is free from imperfections, such as specks or bubbles, and scrupulously cleansed. Of course, if it is already fixed in window-frames, you must take it as you find it. Muslin for pictures is preferable to silk, for its cheapness and possession of great transparency. Whichever may be chosen, observe that it must be tightly stretched upon a frame, and that the muslin be free from coarse threads. Much of the beauty of the work depends on the careful selection of the designs. In experiments, choose a simple design, the subject of which must be left to the fancy of the person engaged in the work. The brushes (hog's hair) will be sufficient for the application of the varnish and cement. Starch, mixed with cold water, and boiled, is the best cement that can be used to make the designs adhere to the glass; but gum or size will do, if more convenient. The cement must be thinly laid on. The washable varnish renders the picture easy to clean, and the clearing liquid is used to destroy the opacity of the paper. It must be applied to the blank side of the picture.

Lay the glass flat upon a folded cloth; then cut out the subjects, and placing them upon the blank side of the grounding paper, (the plain side upwards), trace the outline by rubbing on with the finger a small quantity of blacklead; after this, cut the paper so that the subject may clearly fit it. Much care must be exercised in these operations. The next process in order will be the fastening of the papers on glass. This is done with a sponge and water ; the uncoloured part of the paper must be made quite damp ; then put on the glass and the printed sides a thin coating of the cement. Take care that no air-bubbles remain between the glass and print, and also observe that the papers must be kept damp while the operation is carried on ; for, if the cement is allowed to dry, it will destroy the transparency when the clearing liquid is used.

The cement requires about six hours to dry, when two coatings of the liquid should be applied to the back of the print.

As a remedy, if it is not clear, rub on an additional supply of clearing liquid on the opaque parts. Let the glass remain for twelve hours, that the paper may dry, after which apply the washable varnish. There are other methods, but they are somewhat inferior.

After stretching the muslin or silk tightly on a frame, take the sheets, laying the plain sides upwards to receive the clearing liquid, which put on with a brush, and when dry, give it another coating. A coating of cement will now be necessary to apply to the coloured side of the paper, taking great care to press it equally with the roller. There is now nothing left to the completion of the transparency but to varnish it. If the picture be misty, again use the clearing liquid.

Painting upon Glass or Muslin. For this purpose you will require the following colours: - Raw and burnt sienna, brown pink, Prussian blue, yellow lake, crimson lake, rose madder, French ultramarine, ivory black, burnt umber, gamboge, verdigris. In using these colours, should they work stiffly, work a little turpentine with them. If your painting is on glass, after laying it flat on the print you have chosen to copy, with ivory black and a fine sable-pencil trace the outlines, and after it is dry, let the colouring commence. There is but little difference in the operations of painting on glass or muslin. The latter material should have a coating of parchment size after it has been tightly stretched; but the process of colouring is precisely the same as in the process on glass.

Painting Glass and Muslin in Water-Colours. The same colours are used as those previously enumerated, omitting the verdigris. First, see that the glass is free from grease, and if not, wash it with a little gall. If the operations are to be on muslin, better apply a thin coating of size before working. Add a little gall to your cake colours after they are diluted with water on the slab, and then proceed as in oil colour. Between each layer of colour, as water-colours quickly dry, give the glass a coating of mastic varnish. After the outline is complete, the glass should be placed on a frame, and supported on both sides by an upright piece of wood. The colours may be heightened by applying others of the same tint; and, for the sake of durability, a second sheet of glass should be placed over the work in all departments of this art.

For Using Ordinary Engravings On Glass. The paper they are printed on should contain no size. 1 amp the plain side of the picture with a sponge, and apply to she other a coating of washable varnish; then warm the glass, lay on the print, press with the roller, and place it at some distance from the fire to dry. The next process requires great care, or the beauty of the engraving will be injured. Damp the print again with water, and rub off the super-fluoas paper; after this, and when the miniature has been absorbed, apply the clearing liquid with a camel-hair brush. When it is thoroughly hardened, the washable varnish can be applied, and the work is finished.

Imitation of Ground Glass may be effected by taking equal quantities of ground white lead and sacrum, and mixing with one part of boiled oil and two of turpentine, slightly tinted with yellow or blue. When this is done, take a painter's clean duster, and gently dab with the ends of the hair, until the work has assumed the uniformity of appearance necessary to its perfection.