the most perfect miniature of our days, The object was represented through the whole body and substance of the glass, so that if cut transversely the flower or ornament would still be shown in all its symmetry of parts. Such paintings have on both sides a granular appearance, and seem to have been formed in the manner of mosaic works, of single pieces, but so accurately united that a powerful magnifying glass is unable to perceive any junctures. Numerous antique

specimens of this kind of glass are to be found in the British Museum.

Leaving this description of coloured or stained glass, we come to that particular application of it among the splendid monuments of Gothic architecture, constituting as they do the pride and glory of the middle ages. Since the Reforma

tion, the art of glass staining has been little encouraged, and was considered as an obsolete art by some; however, there were some very fine specimens of stained glass windows produced by Jervis Forrest during the last century, while in the present, the art seems to be again revived, and many of our modern churches boast of very superior productions.

The nature of making coloured glass by means of the oxides of various metals has already been adverted to, and from it we gather, that when certain metallic substances are made, through the agency of heat, to combine with colourless glass, the result is a stain which penetrates more or less deeply into the very substance of the glass itself.

The colouring materials are, in all cases, metallic; gold is employed for purple, a mixture of gold and silver give a rosecolour, iron a brick-red; iron, copper, and manganese, in various proportions, form browns and blacks; blue is obtained

from cobalt. Pure silver possesses the extraordinary property of staining glass yellow, when brought into contact with it at a dull-red heat.

Many compositions are used with these colours as fluxes, in order to promote their fusion when exposed to the heat of the furnace. A fluxing compound very generally used is made by the union of thirty-two parts of flint glass with twelve parts of pearl-ash, and two parts of borax. The fluxes and the colouring materials being thus ground together into a menstruum, this is further diluted and refined with volatile oil, such as turpentine, balsam of capivi, or gum-water, and the artist now proceeds to paint the colourless glass.

A pane of glass, with its pattern attached, is mounted upon the easel, and the figure is painted on the glass with the above prepared colours by means of long-haired sable pencils. The figure intended to be represented may be copied from a pattern laid underneath the glass, or from a design previously prepared. The shading and colouring are sometimes performed on opposite sides of the glass.

When all the tints are laid on and are thoroughly dried, the glass is ready for the first burning. The painted panes are taken separately and placed in a box of iron plate, called a muffle. This muffle is furnished with shelves of iron plate, covered with powdered lime, to prevent the glass coming in contact with the hot metal surface. The muffle is now placed within a furnace, and the contents are gradually brought to a dull, red heat, by means of a fuel that does not produce flame, for which purpose coke and charcoal are usually employed. The heat produced must be exactly sufficient to fuse the flux, by which means the colouring material

Hollow

becomes firmly united to one surface of the glass. tubes pass out from the furnace into the air, through which the process of burning-in the colours can be observed; and it requires the watchful eye of experience to detect the precise moment when the process is complete. The fire is then damped, and allowed to go out gradually, and in ten or twelve hours, the glass slowly cooling and annealing all the while, the process is completed.

When the glass is removed from the muffle, the colours are scraped and brushed separately. If any faults or flaws appear, the colour is again applied, and a second burning is adopted. The second burning also removes spots or stains, and serves to heighten the colours. The colouring matter of the most valuable stains, which has been scraped or brushed from the glass, is again susceptible of use, as only a small portion of that laid on is absorbed by the glass. The process of the second or third firing is conducted in a similiar manner with the first.

In many painted windows the subjects exhibited are those of figures in robes, &c. In these, the face and other parts are painted on a piece of glass of the required form, but the drapery, &c., are cut out from pieces of glass to which various stains have been applied. These irregular pieces are built up in the picture, the joints being made with glazier's lead, care being taken to throw such joints into the shaded parts of the picture.

In addition to the above modes of staining glass, another mode is resorted to when possible. It consists of melting common glass, or its ingredients, mixed with the colouring matter, in a melting pot, in the same way that ordinary glass

is made.

Here the resulting panes are coloured throughout

their substance, and the glass is called pot-metal.

Another mode consists in flashing; that is uniting a thin layer of coloured glass with another layer which is colourless. The coloured layer is sometimes included between two layers of uncoloured glass. Such glass is thus prepared :

The glass-blower has two melting-pots in the furnace—one containing plain and the other coloured glass, each in a melted state; he dips his rod first into the plain glass and then into the coloured, a portion of which adheres to the lump first taken up. If it is desired to enclose the coloured film between two colourless layers, he again dips his rod into the colourless glass. He then proceeds with the process of blowing and whirling, as in the ordinary manufacture of the ordinary crown glass for windows.

It is a singular fact that the art of glass painting, practised with such success during former ages from one end of Europe to the other, should gradually have fallen into such disuse, that, in the beginning of the last century, it came to be generally considered a lost art. In the course of the eighteenth century, however, the art again began to attract attention, and many attempts were made to revive it. It was soon found by modern artists that, by employing the processes always in use by enamel painters, the works of the old masters on glass might, in most instances, be successfully imitated; but they were totally unable to produce any imitation whatever of that glowing red, which shed each extraordinary brilliancy over the ancient windows that still adorn so many of our churches. For this splendid colour they possessed no substitute, until a property peculiar to silver

alone among all the metals, was discovered, which will presently be described.

The art of enamelling on glass differs little from the wellknown art of enamelling on other substances. The colouring materials, which are exclusively metallic, are prepared, as has been before remarked, by being ground up with a flux-that is a very fusible glass, composed of silex, flint glass, lead, and borax; the colour, with its flux, is then mixed with volatile oil, and laid on with a brush. The pane of glass, thus enamelled, is exposed to a dull, red heat, just sufficient to soften and unite together the particles of the flux, by which means the colour is perfectly fixed on the glass. Treated in this way, as we have said above, gold yields a purple, gold and silver a rose-colour, iron a brick-red, cobalt a blue, mixtures of iron, copper, and manganese brown and black. Copper which yields the green in common enamel painting is not found to produce a good colour when applied the same way to glass, and viewed by a transmitted light; for a green, therefore, recourse is often had to glass coloured blue on one side and red on the other. To obtain a yellow, silver alone is employed, which, either in the metallic or any other form, possesses the singular property of imparting a transparent stain, when exposed to a low, red heat, in contact with glass. This stain is either orange or red, according to circumstances. For this purpose a flux is used; the prepared silver is merely ground up with ochre or clay, and applied in a thick layer upon the glass. When removed from the surface, the silver is found not at all adhering to the glass; it is easily scraped off, leaving a transparent stain, which penetrates to a certain depth. If a large proportion of ochre has been employed, the stain is

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