already described must be put into lukewarm water to soften it, and render it easily worked by the hand. When sufficiently pliable, it must be drawn out into long rolls, and put round the edges of the plate, pressing it down firm, and forming it with the fingers into a neat wall or margin. A spout must be formed in one corner, to pour off the aqua fortis by afterwards.

The nitrous acid (spirits of nitre) is now to be diluted with four or five times as much water, or more (according as you wish the plate to be bit quick or slow,) and poured upon the plate. In a few minutes you will see minute bubbles of air filling all the lines that have been drawn on the copper, which are to be removed by a feather; and the plate must be now and then swept, as it is called, or kept free from air bubbles. By the more or less rapid production of these bubbles, you judge of the rapidity with which the acid acts upon the copper. The biting-in of the plate is the most uncertain part of the process, and nothing but very great experience can enable any one to tell when the plate is bit enough, as you cannot easily see the thickness and depth of the line till the ground is taken off.

When you judge, from the time the acid has been on, and the rapidity of the biting, that those lines which you wish to be the faintest are as deep as you wish, you pour off the aqua fortis by the spout, wash the plate with water, and dry it, by blowing with bellows, or by the fire, taking care not to melt the ground.

Those lines that are not intended to be bit any deeper, must now be stopped up with turpentinevarnish mixed with a little lamp-black, and laid on with a camel's-hair pencil; and when this is

thoroughly dry, the aqua fortis may be poured on again, to bite the other lines that are required to be deeper.

This process of stopping-out and biting-in is to be repeated as often as there are to be lines of different degrees of thickness, taking care not to make any mistake in stopping-out wrong lines.

It is also necessary to be particularly careful to stop-out with the varnish, those parts from which the ground may happen to have come off by the action of the acid, otherwise you will have parts bit that were not intended, which is called foulbiting.

When the biting-in is quite finished, the next operation is to remove the bordering-wax and the ground, in order that you may see what success you have had; for till then, this cannot be known exactly.

To take off the bordering-wax, the plate must be heated by a piece of lighted paper, which softens the wax in contact with the plate, and occasions it to come off quite clean.

Oil of turnpentine is now poured upon the ground, and the plate is rubbed with a bit of linen rag, which removes all the ground. Lastly, it is cleaned off with whitening.

The success of the etching may now be known, but it is necessary to get an impression taken upon paper by a copper-plate printer. This impression is called a proof.

If any parts are not bit so deep as were intended, the process may be repeated, provided the lines are not too faintly bit to admit of it. This second biting-in the same lines, is called re-biting, and is done as follows: Melt a little of the etchingground on a spare piece of copper, and dab it a

little, to get some on the dabber; then, having cleaned out, with whiting, the lines that are to be re-bit, heat the plate gently, and dab it very lightly with the dabber. By this, the parts between the lines will be covered with the ground, but the lines themselves will not be filled up, and consequently will be exposed to the action of the aqua fortis. This is a very delicate process, and must be performed with great care. The rest of the plate must now be varnished over, the bordering wax put on again, and the biting repeated in the same manner as at first.

If any part should be bit too deep, it is more difficult to recover it, or make it fainter: this is generally done by burnishing the part down, or rubbing it with a piece of charcoal. This will make the lines shallower, and cause them not to print so black.

Should any small parts of the lines have missed altogether in the biting, they may be cut with the graver; which is also sometimes employed to cross the lines of the etching, and thus to work up a more finished effect.

Dry-pointing is another method employed for softening the harsh effects usually apparent in an etching. This is done by cutting with the etchingpoint upon the copper without any ground or varnish, which does not make a very deep line, and is used for covering the light, where very delicate tints and soft shadows are wanting. By varying these processes of etching, graving, and dry-pointing, as is thought necessary, the plate is worked up to the full effect intended; and it is then sent to the writing engraver, to grave whatever letters may be required to be put upon it.

MEZZOTINTO SCRAPING.

This art is of later origin than the last, and is not of such difficult execution. In mezzotinto prints the shadows are not formed by lines or hatches, but much resemble Indian ink. It differs in the process, however, from aquatinta, although the effect is not very different.

Mezzotinto is chiefly employed in portraits and historical subjects; and aqua tinta for landscape and architecture.

The tools necessary for mezzotinto scraping are the grounding-tool, burnishers, and scrapers.

To lay the mezzotinto ground, lay your plate, with a piece of flannel under it, upon your table; hold the grounding-tool in your hand perpendicularly; lean upon it moderately hard, continually rocking your hand in a right line from end to end, till you have wholly covered the plate in one direction: next cross the strokes from side to side, afterwards from corner to corner, working the tool each time all over the plate, in every direction, almost like the points of a compass; taking all possible care not to let the tool cut (in one direction) twice in a place. This done, the plate will be full, or, in other words, all over rough alike, and would, if it were printed, appear completely black.

Having laid the ground, take the scrapings of black chalk, and with a piece of rag rub it over the plate; or you may smoke it with candles, as before directed, for etching.

Now take your drawing, and having rubbed the black with red chalk-dust, mixed with flake-white, proceed to trace it on the plate,

To form the lights and shadows, take a blunt needle, and mark out the outlines only, then with a scraper scrape off the lights in every part of the plate, as clean and smooth as possible, in proportion to the strength of the lights in your drawing, taking care not to hurt your outlines.

The use of the burnisher is to soften or rub down the extreme light parts after the scraper is done with; such as the tip of the nose, forehead, linen, &c. which might otherwise, when proved, appear rather misty than clear.

Another method used by mezzotinto scrapers, is, to etch the outlines of the original, as also the folds in drapery, making the breadth of the shadows by dots, which having bit to a proper depth with aqua fortis, they take off the ground used in etching, and having laid the mezzotinto ground, proceed to scrape as above.

When your plate is ready for taking a proof or impression, send it to the copper-plate printer, and get it proved. When the proof is dry, touch it with white chalk where it should be lighter, and with black chalk where it should be darker; and when the print is retouched, proceed as before, for the lights; and for the shades use a small grounding-tool, as much as you judge necessary to bring it to a proper colour; and when you have done as much as you think expedient, prove it again; and so proceed to prove and touch till it is entirely to your mind.

AQUA TINTA.

Aqua-tinta is a method of producing prints very much resembling drawings in Indian-ink.