the most beautiful and lively colours, far exceeding those usually employed by modern painters on glass. This dif ference is occasioned not so much by ignorance of the methods pursued in those times, as by the high price of the requisite materials, which would not be defrayed by the little demand there is in the public for works of this nature. Formerly the colour was infused into the substance of the glass itself, or it was only applied on one side, penetrating but a short way into the glass; this last could be done only with certain colours, because others, as yellow for instance, was always found to pervade the whole substance, or at least to go very deep.

In the art of painting on glass, as it is practised in modern times, the first thing to be done is to draw and colour the design on paper: then the artist chooses such pieces of glass as are clear and smooth to receive the several parts of the drawing, distributing them so as to suit the pieces of glass, making the outlines or contours of the figures to fall in the joinings of the several pieces, that the carnations and other bright and transparent parts of the work may not be covered by the leaden joinings of the glasses. When this distribution is made, each piece of the glass is marked, corresponding to that part of the sketch to which it belongs: thus the design is transferred from the paper to the glass, by means of a black colour, formed as was before described, diluted with gum water, following all the lines and strokes as they appear through the glass, with the point of a pencil. The other colours are applied with gum arabic, much in the same way as in miniature painting.

When the painting is completed, the pieces of glass are carried to the oven or furnace, where by the intense heat the colours are incorporated with the substance of the glass In the furnace the glasses are placed in an earthen pan, separated by layers of pulverised quick lime : the whole furnace is then covered with a broad flat tile, and closely stopped

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all

all around. When this baking or annealing is finished, the fire is extinguished as quickly as possible, to prevent the glasses from being broken, and the colours from being burnt dissipated or changed.

ENGRAVING.-Engraving is executed on various substances, metals, stone, wood, glass: that on plates of copper is generally understood when engraving is mentioned. This consists in forming concave lines, on a smooth surface of copper, conformably to some delineated figure or design, by nicans of either a sharp cutting tool, or of some corroding solvent liquid, so as to render the plate capable, when charged with any coloured fluid, of imparting by pressure an exact representation of the figure or design to paper or other proper substance.

Of engraving there are many varieties, such as the following, viz.

1. Engraving in strokes with a sharp pointed tool; the copper-plate being first covered with a composition or ground, and the strokes afterwards corroded with aquafortis; this is termed etching. The ground is composed in different ways, but commonly of pure wax, mastic, bitumen and amber; these substances are reduced to powder and melted over a slow fire, they are then poured into water to consolidate, and made into balls for use. When the ground is to be applied the copper-plate is heated, but so as not to be sineked; a ball of the composition tied up in a piece of thin silk is then rubbed over it, observing that the compo sition be as equally thick as possible in every part of the plate. The ground is next smoked by holding it over a lamp; and when the plate is cold, the outlines of the print or drawing may be traced on the ground. These outlines are obtained by applying on the ground the back of the print, &c., previously rubbed over with red chalk, flake white, or black lead in powder, or any other substance that will readily yield a legible mark; then with a blunt needle

trace

trace lightly all the out-lines, the shadows, &c. &c. of the drawing. When this operation is finished the drawing is removed, and the plate is ready for etching, which is performed by tools nearly resembling sewing needles, but stronger, and inserted into handles, the points being of various sorts for the different parts of the work. With these tools the etcher, following the outlines he has traced, penetrates through the ground to the copper, making the strokes stronger or fainter conformably to the lines in the original drawing or print. When the etching is finished a border of soft wax is raised all round the work on the plate about an inch in height, and some aquafortis mixed with water is gently poured on the plate, when it will soon begin to corrode the copper in the strokes made through the ground. When the corrosion or biting, as it is termed, is supposed to be sufficient on the fainter parts, the aquafortis is poured off and the plate washed with water and dried; that part of the ground being scraped away the copper may be examined. When the fainter parts of the work are sufficiently bitten, they are stopped up with a proper varnish, and the aquafortis is again applied to excavate the remaining stronger parts of the etching. By heating the plate the border and ground are easily removed, the plate cleaned, and any defects supplied by means of a graving tool.

2. Engraving in strokes with the graver alone, unassisted by aquafortis.—In this species of engraving the design is traced with the dry point, (which is a sharp tool,) upon the plate, and the strokes are cut in the copper by the graver: this is generally called engraving with the tool and dry point only.

3. In strokes, but which are first etched with aquafortis, and then finished with the graver, by which the two former methods are united. This mode is the most commonly practised, and has also the best effect,

4. In dots without strokes, which are performed with the

point upon the wax or ground, and then bitten in with aquafortis as in etching; but these dots are afterwards softened and harmonised by means of the graver making small additional dots between them. This mode is sometimes executed with the graver a',ne, in the carnations and other finer parts of portraits.

5. In dots which, like the foregoing, are first etched, and afterwards harmonized with the dry point assisted by a little hammer, instead of the graver, for which reason it is termed opus mallei, hammer-work; but this method is now nearly exploded.

6. In mezzotinto, which is performed by covering the plate with a strong dark ground or deep shade, by means of a toothed tool, and corroding the dots with aquafortis. The parts which are to be light are then rendered more or less smooth by the scraper, according to the degrees of illumination they are to represent.

7. In aquatinta, a mode of engraving lately invented, but now brought to great perfection in this country: in this the outline is first etched, and afterwards the copper is corroded in such a manner, that an impression from it exhibits the appearance of a colour or tint laid on the paper itself, or of a drawing in Indian ink. This is accomplished in various ways, by covering the copper with some substance which assumes a granulated form, thus preventing the acid from acting on the copper in the places where its grains adhere to the plate; and consequently the copper is but partially corroded. The more minute are the particles of the grain, the more nearly will the impression resemble a drawing of Indian ink; but the larger the particles are, the more distinct will be the granulation.

8. Engraving on wood is performed with one block, or with several. When one block of wood is used, the design is traced on it with a pen, and those parts corresponding to the lights or whites of the design are carefully hollowed

out;

out; the letter-press printers afterwards employ this block in the same way as they do the types in printing a book. When two, three, or more blocks of wood are employed, the first has the outline cut upon it, the second contains the darker shadows, the third the shadows terminating on the lights: these are all used in succession, each print receiving an impression from every block. This mode of engraving was designed to represent the drawings of the old masters of painting.

Of all the foregoing modes of engraving, the most antient is that on wood, or rather the earliest impressions on paper were taken from carved wooden blocks. For this invention the world is probably indebted to the makers of playing-cards, who practised the art in Germany, about the beginning of the 15th century; the earliest date of any wooden cut is 1423. Germany also had the merit of producing the first prints from engraved copper about the year 1450; the earliest date however is only in 1461.

THE