Engraving, the art of producing designs, either by incision or by corrosion, on the smooth surface of a wooden block, metallic plate, or other substance, for the purpose of transferring them to paper. In this sense the art is comparatively modern, being but little older than that of printing, but in a more restricted sense it has been practised from a remote antiquity. Engraving on metallic plates is mentioned in Exodus xxviii. 3G, and numerous other passages attest that the Israelites were skilful in it, and also in gem and seal engraving. They acquired the art undoubtedly from the Egyptians, who, as well as the Assyrians, engraved both on stone and metal. Specimens of incised copper plates found in mummy cases show that they were executed with tools similar to those now in use, and impressions taken from them at the present day prove that the ■ Egyptians needed but a single step to make the discovery of engraving in its modern sense; but the idea of filling the incisions with color and taking a print from them on paper seems never to have occurred to them. The Assyrians even went so far as to take impressions from their engraved slabs in clay; and wax and other plastic substances were used for a similar purpose.

Herodotus, speaking of a period 500 years before Christ, mentions a tablet of brass on which was a map of "every part of the habitable world, the seas, and the rivers." In India and in China the art was practised from the most remote ages. Indeed, the various processes of metallic engraving, die sinking, and gem cutting prevailed among every ancient people who had made any progress in civilization. In its more modern sense, engraving was probably first practised on wood, but its origin is involved in obscurity. The Chinese assert that they printed from engraved wooden blocks more than 1,000 years before Christ; but as they were unacquainted with the art of making paper until about A. D. 100, their assumption may be doubted. It is generally conceded, however, that they practised the art at an early period, and it is supposed that it was introduced from China into Europe through the intercourse of Venetian merchants. Marco Polo describes the making of paper money in China by stamping it with a seal covered with vermilion. This was about the close of the 13th century, but even this simple art was not practised, so far as is known, in Europe until about a century later.

Playing cards and rude cuts for devotional manuals were printed from engraved blocks in Italy, and perhaps in Germany, as early as the year 1400, if not earlier. A decree of the magistracy of Venice, dated Oct. 11, 1441, forbids the importation of any work printed or painted on cloth or paper, because the mystery of making playing cards and printed figures had fallen into decay on account of the influx of foreign manufactures. The " St. Christopher" of 1423, a woodcut of folio size, in the collection of Earl Spencer, was supposed for a long time to be the most ancient example of engraving known; but the baron von Reiffenberg recently discovered one of 1418, and M. Henri Delaborde found two plates printed on the leaves of an old manuscript which prove the existence of wood engraving and the use of the printing press in 1406 (Gazette des Beaux-Arts, March, 1869). Among the earliest specimens of illustrated books that have come down to us is the so-called Biblia Pauperum, supposed to have been produced between 1430 and 1450. It is a small folio of 40 leaves, each containing a picture, with a text of Scripture or other explanatory sentence below it.

The Speculum Humanoe Salvationis, another noted example of block-book printing, dating from about 1470, consists of 63 leaves of the same folio size, containing 58 pictures, with two lines of Latin rhyme under each. The legends on these early pictures led to the invention of printing. Many works printed in Italy, Germany, and England during the latter part of the 15th century were adorned with cuts, but they were generally of the rudest kind, with broad heavy lines. Near the beginning of the 16th century "cross hatching," as the lines of shadow crossing each other are technically called, was first practised. It was freely used in the Nuremberg chronicle in 1493. The art made rapid progress, and early in the 16th century reached a high degree of excellence. The engravers invented about this time a way of joining the blocks together so that plates of very large size were made. One representing the triumphal arch in honor of the emperor Maximilian I. measured 10 by 9 ft. About 1610 wood engraving began to decline, and at length was applied only to tapestry and calico printing.

The art was revived in recent times, the chief impulse being given to it by the founding in England of the "Penny Magazine" about 1833. This work was to contain many illustrations, and to be published cheaply and at short intervals, which made it necessary to print the pictures with the letterpress. This could be done with wood engravings only, and great pains were taken to make improvements in the art. Since then it has made rapid advances, and has resumed the place in book illustration from which plate engraving for a time deposed it. - German scholars long regarded Martin Schon or Schongauer as the inventor of plate engraving, quoting some impressions executed, according to them, about 1460; but the abbe Zani found in Paris a proof of a pax representing the coronation of the Virgin, dated 1452, the original plate of which, by Maso Fi-niguerra, is still preserved in Florence. This would seem to corroborate Vasari's assertion that the first use of a metal plate for engraving was by Finiguerra, a goldsmith of Florence, who practised the decoration of gold and silver plate with niello work, a process consisting of running into lines cut in the metal a black alloy of silver, lead, copper, sulphur, and borax.

The surface, when scraped down and polished, appeared beautifully ornamented according to the skill and taste exhibited in the pattern. To obtain a copy of the engraved figure before filling it, Finiguerra is said to have applied soot and oil and taken an impression on damp paper; and thus was made the first print on paper from a metallic plate. But Passavant, in the Archives de Naumann (1858, p. 1), describes an engraving of the Virgin bearing the date of 1451; and Renouvier in a recent pamphlet reveals the existence of a series of prints of the "Passion" made in 1446. The earliest works were executed on tin, zinc, or iron; but copper soon became recognized as the metal best adapted for engraving, and until the invention of steel engraving it was used almost to the exclusion of other metals. The art spread quickly over Europe. Painters of distinction, as Botticelli, Andrea Mantegna, Giovanni Bellini, Campagnola, and others, gave their attention to it, and it was rapidly perfected. This was especially the case in Germany and the Netherlands, where it was adopted by many eminent men, among whom Albert Durer is particularly distinguished.

Rembrandt, Vandyke, and other great painters also executed valuable works with the etching needle, and Raphael highly prized the services of the great Italian engraver Marc Antonio, who transferred to copper many of his designs. The art was introduced into England at an early period, an illustrated work called the "Golden Legend" having appeared in 1483, and in 1543 Vesalius's work on anatomy, in Latin, illustrated with copperplate engravings. Maps of English counties were engraved in 1579, but little progress was made previous to the 18th century, when Vertue and Hogarth, and subsequently Strange, Woollett, Barto-lozzi, Sharp, and others, brought the art to a high degree of excellence. Italy is no longer preeminent for her engravers; but within the century she has furnished some of transcendent merit, whose works will compare with the best of their predecessors. At the head of these stands Raphael Morghen (died 1833), whose "Last Supper" after Da Vinci, and "Transfiguration" and Madonna della Seg-giola after Raphael, are among the most costly productions of the art. Schiavoni, the An-derlonis, Bettelini, Longhi, Porporati, Pavon (a pupil of Raphael Morghen), and others, have engraved with success many of the works of the old masters.

Toschi (died 1854) took high rank among line engravers by his print of the "Entry of Henry IV. into Paris," after the picture by Gerard, as well as by his " Descent from the Cross," after Volterra, Spasimo di Sicilia, after Raphael, and other works from the old masters. Rosaspina, Bisi, Mercuri, and others, have produced many meritorious prints from masters both old and modern. In Germany the art has witnessed a steady improvement since the beginning of the century. Rahl, Hess, Reindel, Umer, Leybold, Kessler, Kobell, Barth, Klein, J. II. and J. J. Lips, Steinla, and others, have gained eminence as line engravers; and Christian Friedrich von Muller, who died in 1816, aged 33, produced a print from Raphael's Madonna di San Sisto, which is regarded as one of the noblest achievements of the graver. His father, J. G. von Muller, was also a good engraver, and among other works executed the well known print of the battle of Bunker Hill from Trumbull's picture. The renaissance in German painting, effected by the efforts of Cornelius, Overbeck, Schadow, Kaulbach, and others, has had a marked influence on the art of engraving, and within the last half century has arisen a school of engravers who have cooperated with these masters in their endeavors to restore to art its ancient simplicity and deep religious feeling.

Prominent among these are Ruscheweyh, who was associated. at Rome with Cornelius and Overbeck, and who has engraved the chief works of the new school; Amsler, Keller, the Felsings, and Merz, who have drawn their inspiration from the same source; Thater, Eichens, Mandel, Rahn, and Schleich, who, among other works, have engraved some of the masterpieces of Kaulbach, Schnorr, Scheffer, etc. In France as in Germany the efforts of engravers are now less directed to the reproduction of the works of the old masters, or of indifferent designs for illustrated books, than to the execution of prints after contemporaneous painters. David, Gros, Ingres, and others, have afforded numerous subjects; and of such popular painters as Vernet, Delaroche, and Ary Scheffer, nearly every important work has been engraved. Yet France has produced some excellent line engravers after the old masters, among whom may be mentioned the baron Desnoyers (died 1857), who executed fine prints of Raphael's Belle jardiniere and "Transfiguration," and of Gerard's Napoleon; Prevost (died 1861), who engraved Paul Veronese's " Marriage of Cana;" the Mas-sards, Lecomte, Lorichon, Bein, Richomme, Forster, Martinet, Lignon, Gudin, Audouin, Bridoux, Girard, etc.

Of those who have devoted themselves to the works of modern masters, the most eminent perhaps is Hen-riquel-Dupont, whose line engraving of Dela-roche's fresco in the hemicycle of the palais des beaux-arts is unsurpassed in merit or dimensions by any recent work of the kind. Blan-chard, Prudhomme, Louis, and the brothers Francois, have engraved many of the works of Vernet, Delaroche, and Schetfer, and C. R. J. Francois has confined himself exclusively to Delaroche's works. Girardet (died 1865) engraved from these masters, and also several subjects from American history, including Loutze's "Washington Crossing the Delaware," Stuart's portrait of Washington, etc. Jazet is celebrated for his aquatints from the battle pieces of Gros and Vernet, and Cala-matta (died 1869) executed admirable portrait prints of Lamennais, Guizot, Fourier, and Madame Dudevant. Calame, a Swiss artist (died 1864), produced many admirable etchings. The practice of copying the old masters, and to a considerable extent of line engraving, has fallen into disuse in England, the latter being employed principally in large landscapes or in the higher class of figure pieces.

Here again, as in Germany and France, the works of a few eminent native artists have occupied the attention of the chief engravers almost exclusively, and under the influence of painters like Reynolds, Lawrence, Wilkie, Turner, and Landseer, the art has been prosecuted with great success. Raimbach, Stewart, Burnet, Smith, and others, have made Wilkie's pictures generally known through the medium of excellent line engravings; and Goodall, Will-more, Pye, Wilson, Prior, Finden, Wallis, and Cousen have done the same for the landscapes of Turner, Stanfield, Constable, Callcott, Roberts, and the other great English masters of this department of painting. Martin's mezzotints of the "Fall of Babylon," "Belshazzar's Feast," etc, after his own designs, are striking works and well known. The engraving of Sir Edwin Landseer's works, of which nearly 200 different prints have appeared, has employed a numerous band of engravers, prominent among whom are the artist's brother Thomas Landseer, Cousins, Lucas, Bromley, Ryall, Atkinson, Baker, Wass, Gibbon, Graves, Bacon, and Robinson. Doo, Watt, Heath, Hollaway, who engraved the cartoons of Raphael in Hampton court, and others, have produced good line engravings from the old masters; and the more modern English painters, such as Leslie, Newton, Eastlake, Etty, Ward, Webster, Maclise, Millais, Frank Stone, Herring, and T. Faed, have found ready interpreters in Richardson, Bellin, Sadd, Howison, Walker, Simmons, Stocks, Reynolds, J. Faed, Hall, and many others.

The etchings of George Cruikshank from his own designs are also of the highest order of merit. Wood engraving in Europe, and particularly in England, has reached a perfection unknown to any previous era in the history of art; and in the latter country the woodcuts of the Dalziel brothers, Evans, Cooper, Palmer, Linton, and others, have a richness and delicacy of finish not inferior to the highest efforts of the engravers on metal. In the Netherlands the principal engravers are Vinkeles and Van Genus, Van Trostwyck, Van Os, Overbeck, Jan-son, Chalon, Claessens, De Frey, and Corr. In the United States the most eminent names are Durand, Cheney, Smillie, Danforth, Dick, Hal-pin, Marshall, and Andrews. - According to the material used for receiving the designs, the art is designated as xylography, chalcography, siderography, and lithography - from wood, copper, steel, and stone. The last will be treated under its own designation. Engraving proper may be considered under two heads: wood engraving, where the print is made from a surface, and plate engraving, where the impression is made from lines cut into the metal or other substance on which the engraving is made. I, Xylography, or Wood Engraving, is the earliest, simplest, and cheapest form. Various woods are used, boxwood exclusively for fine work, and mahogany, maple, and pine, and occasionally pear, apple, and beech, for coarse work. The old engravers cut on large blocks of soft wood, such as pear tree, the way of the grain; those of the present day use small blocks of hard wood, and cut across the grain. Some soft woods, such as pine, used for engraving placards and posters, are still cut with the grain. In preparing boxwood blocks, the log is sawn into transverse slices, "type high" (about 15/16 of an inch), so that the face of the engraving will be even with the type when in the form. After thorough drying, to prevent warping and cracking, it is trimmed square.

If the cut is large, a number of these blocks are put into the hands of different engravers, each of whom executes a part, and the various pieces are then fitted together and securely clamped. In this manner a very large engraving can be produced in a short time. The face of the block having been made smooth and free from inequalities, the artist covers it with a light coat of flake white mixed with gum water. This makes a ground for the drawing, and retains pencil marks or India ink. Drawings may be made with a lead pencil, pen, brush, or with brush and lead pencil combined. The drawings of the time of Albert Durer are supposed to have been made with pen and ink. Modern drawings, not being fixed, are liable to be obliterated by the engraver, and are usually covered with paper, a small piece being torn away from the part on which he is engaged. Drawings made with the lead pencil and the pen require more mechanical than artistic skill in the engraver; those with the brush, or brush and pencil combined, the reverse. The work of the wood engraver is precisely the opposite of that of the plate engraver. The latter cuts the lines of the drawing into the metal; the former cuts away the surface around the lines, leaving them in relief.

There is a method of wood engraving in which the lines are cut in the block as in plate engraving. It differs from the latter in that the ground receives the ink instead of the lines, which thus appear white on the paper.

Fig. 1. - Tools for Wood Engraving. 1. Elliptic. 2. Gouge. 3. Chisel. 4. Tint. 5. Lozenge. 6. Graver. 7. Tool for Pine. 8. Tool in Handle.

Modern engravers use a greater variety of tools than were known in the early stages of the art. The old engravers had only small knives and gouges; now the artist has gravers of different widths to cut out the spaces between fine lines, and broader chisels and gouges to remove wide spaces. Fig. 1 shows the different tools used. Parallel lines, used largely in wood engraving where a flat even appearance is desired, are made by the ruling machine, which produces effects in relief printing similar to those of the ruling machine in plate engraving. (See fig. 2.) II. Plate Engraving. Engraving on metal plates may be classed under the following heads: etching, line, stipple or chalk, mezzotint, and aquatint. The instruments used are the same, with some modifications, in all the styles. The etching needle or point is a piece of stout steel wire inserted in a handle and ground to a fine point on a hone. Two or three needles, of different thicknesses, are used, some for broad and some for fine lines. The dry point is a similar instrument, but with a more delicate point, used for making outlines to be filled up afterward by the burin or graver.

The latter, the principal tool of the engraver, is a small instrument of tempered steel, with one end ground off obliquely so as to produce a sharp cutting point, and the other inserted in a handle. Several are required, the ends of which differ in form from a lozenge to a square, the former for cutting fine, the latter broad lines. The angle at the meeting of the two lower sides is called the belly, and the breadth of the end the face. The scraper is an instrument used for taking off the burr raised on the metal by the cutting tools. The burnisher is employed to soften lines bitten in or engraved too deep, or to polish the plate when scratched. - Etching may be classed under two heads, painters' etching and engravers' etching. The former is a method of engraving which was practised by many of the old painters, and which has recently come into fashion again among artists. The process is nearly the same in both cases. In painters' etching a copper plate is used, which is covered with a film composed of asphaltum and wax, technically called the etching ground. This ground is blackened with lampblack mixed with the varnish.

The engraver then makes his drawing with etching needles, cutting through the ground to the plate, making his lines fine or broad according to the depth required, working as he would with a pen or pencil. A border or bank of wax is then raised around the plate, and diluted nitric acid is poured over it. The etching ground resists the action of the acid, which corrodes only the parts uncovered by the needles. "When the work is well bitten in, which will be in about a quarter of an hour, the acid is poured off and the plate cleaned, when a proof is taken. If the lines of the lighter parts appear to be sufficiently etched, they are painted over with some of the asphaltum ground dissolved in spirits of turpentine or with sealing wax dissolved in alcohol, and the acid is reapplied to the other parts. This covering of a portion of the plate is called stopping out, and the process of stopping out and biting in is continued until the required depths of line are all attained. Three bitings in are generally enough for a painter's etching. Lines too strongly bitten are rubbed up with the burnisher. Various modifications of this process have been used. Other processes also are in use, for which certain advantages are claimed.

That invented by P. G. Hamerton in 1871, and named by him the "positive process," is much practised. The plate is brightened first with cyanide of silver, on which is laid a ground of white wax dissolved in ether, the effect of the ether being to purify the wax. After drying for three days, a second coat of wax is applied, and the back and edges of the plate are painted with Japan varnish. When ready for use, the plate is placed in a shallow bath, into which it is fastened by balls of wax pressed into the corners. The mordant, composed of chlorate of potash 20 grammes, hydrochloric acid 100, and water 880, is then poured over the plate so as to cover it completely, when it is ready for the artist, who sketches with the usual needles or with strong sewing needles fastened in a handle. If the bath is in proper condition, the line will blacken as soon as it is drawn. If a second or a third biting in becomes necessary, the plate must be cleaned, resilvered, and coated with fresh wax. The advantages of the positive process are that the artist sees his work in black on a white ground, as in drawing with a pencil on paper, and the lines never glisten as in the old method. The invention of etching is generally attributed to Albert Durer, but it is probable that it was practised before his time.

Rembrandt is the representative etcher, and some of his works command very high prices. One known as the hundred-guilder print has been sold for £1,180. Rembrandt founded the Dutch school. Among his followers, Ostade produced some fine works, and the etchings of Bega, though wanting in delicacy, are prized for the spirit and life of the figures. The landscapes and' cattle pieces of Nicholas Berghem and the animals of Paul Potter are celebrated. Vandyke's etchings are as noted as his paintings. Of the French school, Jacques Callot, Charles Meryon, Lalannc, Jules Jacquemart, Charles Francois Daubigny, Appian, and Jongkind have produced remarkable works. Among English etchers of note are Turner, David Roberts, Wilkie, Geddes, Ruskin, Landseer, Cruikshank, Doyle, Whistler, Samuel Palmer, and Hamerton. Germany is not particularly noted for etchers, and in Italy Canaletti alone is prominent. A number of American artists have practised etching within the past few years, but they have confined themselves generally to humorous subjects. The best treatises on the subject are that by Lalanne (Paris, 1865), and P. G. Hamerton's "Etchers and Etching" (London, 1868). Etching is employed largely for producing ornamental designs on glass.

The method is the same as in etching on copper, but the acid used is hydrofluoric, generated in a leaden vessel over which the prepared glass is placed. - Engravers' etching is engraving executed with the tracing point instead of the burin, and bitten in with acid. A portion of every composite steel engraving is etched.

Fig. 2. - Ruling Machine. A. Foundation. B. Bed Plate. C. Revolving Plate. D. Feed Wheel and Screw. E. Tool. F. Carriage. G. Wave Roll.

Fig. 3. - Steel Engraver's Tools. 1. Scraper. 2. End View of Scraper. 3. Burnisher. 4. Burin.

An engraver's etching differs from a painter's in that it is unfinished, the work being only initiatory to that of the burin. Engravers of historical and other subjects, including figures, etch little more than the outlines and the broad masses of the draperies; but landscapes, skies, architectural work, and animals are generally produced in this way. In map engraving, the sinuous lines indicating coasts and the banks of rivers, the marks denoting swamps, and the outlines of mountains are etched. Roads, canals, the waters of lakes and rivers, groups of houses, etc, are put in with the burin. Lines which can be ruled are made with the dry point, and cities, towns, and villages, represented by various kinds of circles, are engraved with an instrument peculiar to map makers. - Line engraving is the art of rendering or translating forms, materials, and colors or effects of a picture into black and white through the medium of lines engraved or sunken in the surface of metal plates or other materials, from which impressions may be printed. Forms are rendered by the directions and courses of the lines, effects and color by the depth and width of the lines and their distances from each other, and materials or surfaces by the quality of the lines.

The highest grade of line engraving is executed with the burin or graver directly on the metal, and is limited to reproductions of the human figure. Delicate lines are put in with the dry point. This does not cut clean, like the burin, but leaves a burr which is removed with the scraper. Parallel lines required in series, such as those in flat tints in skies or in buildings, are cut with the ruling machine, which produces more even tints than hand work, but at the expense of freedom. The lines too, unless very skilfully ruled, wear quicker and become clogged with ink sooner than those made with the graver. - Stipple engraving is executed in dots instead of lines, and is practised commonly in connection with etching. The plate is covered with the etching ground, and the subject is transferred to it in the usual way. The outline is then laid in with small dots with the graver, and the darker parts are etched in larger dots laid closely together. The ground is next removed and the work finished with the graver. For producing great delicacy in shading, a fine dry point is used. Stipple engraving was much practised by the English in the latter part of the last century. It is combined frequently with line engraving on the same plate.

It is well adapted to give a soft pleasing effect in shading the human figure, and is employed therefore in portraiture and in engravings of sculpture. It is sometimes called chalk engraving, because used to imitate drawings in chalk. In this case the dots are made with less regularity and uniformity in size. Sometimes the dots are struck in with a hammer, when the work is called opus mallei, but this is little practised. Stipple engraving dates from the end of the 17th century, and Morin and Boulanger are considered as the inventors. In 1740 Francois invented an instrument called a roulette, a small steel wheel with a toothed edge, which being rolled over the plate produced dotted lines. This was used chiefly in chalk engraving. - Mezzotint engraving differs from other styles both in execution and in the appearance of the impressions given by the plate. A mezzotint engraving resembles a drawing washed in with the brush, rather than a work executed with a steel instrument. The operation is the opposite of that in other methods. In ordinary engraving the process is from light to dark, in mezzotint from dark to light. The plate is prepared by running over it a toothed instrument called a cradle, which raises a burr all over its surface. This is called laying the ground.

A print taken from the plate at this stage would be uniformly black, while an ordinary plate previous to engraving would give no impression. The plate being thus prepared, the lights and shades of the engraving are produced by rubbing away with scrapers and burnishers the parts where lights are desired, and by increasing the indentations for deeper shades. An agreeable softness is produced by the harmonious gradations of the tints more easily than by other methods. By etching the outlines before laying the ground, a more decided character is given to the print. A pure mezzotint engraving is seldom produced, the process being combined usually with line and stipple. Mezzotint plates are now prepared by a machine invented by Saulnier for ruling lines. This style of engraving is supposed to owe its origin to Ludwig von Siegen, an officer in the army of the landgrave of Hesse, whose first work was published about 1640. It was introduced into England by Prince Rupert, and several prints executed by him are still in existence. - Aquatint engraving is so called from the similarity of its effect to a drawing in India ink or bistre.

After the design has been etched in outline, and the etching ground removed, a solution of resin or of Burgundy pitch in alcohol is poured over the plate as it lies in an inclined position. As the alcohol evaporates, the resinous matter is left in granulations over the surface. The design is then drawn with a gummy sirup called the bursting ground, which is applied wherever a shade is to be produced. The lights are left untouched. The whole is next covered with a coating of turpentine varnish, and a border of wax is raised around the plate. Water is poured upon it and left for 15 minutes, when the bursting ground cracks open, exposing the copper. It is then ready for the nitric acid, which is used as in etching, and may be applied several times after each stopping out of the portions sufficiently corroded to produce the desired shades. The bursting ground is not always required, the acid being applied directly upon the granulations, which protect the parts they cover, and the varying shades are produced by repeated corrosions and as many stoppings out. Some artists dust certain resinous powders on the plate instead of obtaining the granulations by the alcoholic solution.

Gum sandarac is used for this purpose, or the purest resin pulverized, and sifted through muslin upon the plate, to which the particles attach themselves on its being heated. Colors are sometimes applied to the plates, and the design is at once printed in its intended colors; but where several colors are employed in contact with each other, it has been customary to use as many different plates, one for each color, and print in succession, the plates being kept in their exact places by fitting upon four fixed pins that pass through holes in their corners. This method was formerly practised in printing cotton cloth. Aquatint has been superseded by lithography and chromo-lithography, and is now but little used. The process is a French invention, and originated with J. B. Leprince about 1787. It was perfected by English artists, who executed works of great merit by this method. - Copper was used almost entirely for plate engraving until the present century, when the discovery by Jacob Perkins, of Newbury-port, Mass., of a process for decarbonizing steel made steel-plate engraving possible.

The metal had been employed once in England in 1805, in the engraving of the ceiling of the star chamber in Smith's " Topographical Illustrations of Westminster;" but its hardness prevented its general use. Since Perkins's invention steel plates have gradually supplanted copper, and now no artist who understands the relative capabilities of the two metals uses the latter for fine engraving. Another invention of Perkins's, the transferring process, effected a still greater revolution in the art, more especially in the production of small engravings, such as vignettes and other cuts for bank notes. Its advantage is that the plate, after being engraved in the usual manner, can be used to transfer the design to other plates, so that an indefinite number may be produced from the original. The softened plate when finished is reconverted into steel, and a decarbonized cylinder large enough to receive the impression is then rolled over it by means of a powerful machine until the engraved impression appears on it in relief. The cylinder is then hardened, after which it can be used for returning the impression to softened plates, each of which will be an exact counterpart of the engraved plate.

The original thus serves to give but one impression to the transfer roller, which in turn is used to make any number of plates. The most important application of this process is for engraving bank notes, which branch of the art is treated below. The plates of notes are transferred usually in parts, a single vignette or figure at a time. In some cases the entire plate has been put on the roller, but to do this successfully requires the utmost care on account of the spreading of the softened steel under pressure. - Bank-note Engraving. The art of engraving owes some of its most important developments to the efforts of artists and mechanics in manufacturing bank notes. In the United States this business has nearly attained perfection, and whatever skill has been shown in Europe in bank-note engraving has been the result of improvements introduced from this country. The rude, cheap notes issued by the bank of England a century and a half ago were reproduced for nearly a hundred years, when frequent forgeries rendered a change necessary. In the year 1800 the directors first endeavored to furnish notes which should be secure from counterfeits, but forgeries multiplied, and it was not till 1820 that any remarkable improvement was made in the style of engraving them.

In the United States a superior system had existed for some years. The continental notes, the first of which were issued in 1775, were engraved on copper by Paul Revere of Boston. They were of no importance as works of art, and the notes engraved afterward for the bank of North America were little better; but the invention of the transferring process by Perkins raised bank-note engraving to the rank of a special art. Perkins acquired so great a reputation as a manufacturer of bank-note plates that in 1808 a special law was passed in Massachusetts directing the use of a peculiar style of note with a "stereotype check," invented by him, by all the banks of the commonwealth. This, though a sufficient protection against counterfeiting at the time, grew so familiar in 20 years that fraudulent imitations became numerous, and the law was finally repealed. About 1814 Perkins associated himself in Philadelphia with the firm of Murray, Draper, and Fairman, with whom he remained several years, still experimenting with his machinery. While he was there Asa Spencer, who was connected with the same firm, invented a method of applying lathe work to bank-note engraving.

This adaptation of the geometric lathe, although but a new application of an old principle, was made so successfully that Spencer received as high credit as if he had been the original inventor. To Mosley I. Danforth also, a native of Hartford, Conn., who spent 12 years in the study of his art in London and Paris, is due much credit for the rapid advancement of banknote engraving in this country. He associated himself with Murray, Draper, and Fairman, and compelled rival engravers to adopt a higher standard by the exquisite style and finish of his work. In 1818 Mr. Perkins, attracted by the liberal propositions for competition offered by the bank of England, went to London, accompanied by Mr. Fairman and a number of experienced workmen. The superiority of his work was immediately perceived, but not so readily acknowledged; and unfortunately for his prospects, a London wood engraver, Mr. Darton, succeeded after many efforts in making a woodout copy of one of his pieces of lathe work, a circumstance which was so strongly urged as an argument against the American competitor that he was obliged to withdraw from the contest, and the privilege of manufacturing the notes was awarded by the bank to Messrs. Applegarth and Cowper in 1820. But so confident was Mr. Perkins in the security of his notes, that when supplying a bank in Ireland he voluntarily agreed, if they should be forged, to furnish a new issue without charge.

Perkins remained in London, where he established a partnership with Mr. Heath, an eminent engraver, which lasted during his life. His improvements were adopted in England and in some parts of the continent; but bank-note engraving has been much less developed in Europe than in the United States. In the bank of England security against counterfeiting is sought by the use of a peculiar kind of paper rather than by fine engraving. The notes are printed from an electrotype surface, a method fatal to delicacy of work, although possessing the advantages of speed and cheapness. By this system, introduced by Mr. Smee in 1854, the engravings are used as moulds from which electro-casts are taken, and the notes are printed from these upon steam presses. The paper is made by hand in moulds which are just large enough to form a sheet for two notes. After printing, these notes are separated by an irregular cut, so that each has a selvage on three sides and on the fourth an indented edge. The notes of the bank of France are printed also from a surface, but they are neater in engraving and more elegant in execution than those of the bank of England. The artistic perfection which characterizes banknote engraving in the United States is the result of a public necessity growing out of our banking system.

Under the old local system the issues were so numerous that familiarity with the different notes became impossible; and as the laws furnished no sufficient protection against counterfeiting, other means had to be adopted for security. This was attained in the superior execution of the notes themselves, and by the combination of the highest artistic excellence with mechanical skill, perfect counterfeiting is rendered almost impossible. The business of bank-note engraving is carried on in the United States by three companies, the "American," incorporated in 1858, the "National," in 1859, and the "Continental," in 1862, all of which are in the city of New York. A large part of the bank notes, bonds, and postage and revenue stamps used by many of the principal nations of the world are made by these corporations. Among the foreign nations for which work has been done are Russia, Sweden, Italy, Greece, Spain, Switzerland, the British North American provinces, Cuba and other West India islands, United States of Colombia, Venezuela, Ecuador, Mexico, the states of Central America, Brazil, Peru, Bolivia, Chili, Argentine Republic, Paraguay, Uruguay, Japan, and the Hawaiian islands.

The national currency and legal-tender notes of the United States, the national bonds, and the revenue and postage stamps, are all made in whole or in part by them. To insure greater security, most of the currency is engraved and printed in three establishments, the same notes passing through two of the companies here and then going to Washington, where they are finished. - The American bank-note engraver confines himself to line engraving on steel; stipple, mezzotint, aquatint, and other methods not being suitable for his purposes. In order to attain the greater security against imitation, the engravings are made elaborately fine, from drawings by the best artists, and the plates are decorated with geometric designs cut by machinery with an exquisite minuteness and regularity impossible to be accomplished by hand. Prominent among American designers of vignettes are the names of A. B. Du-rand, J. W. Casilear, James D. Smillie, F. O. C. Darley, and James Macdonough. The drawing of a vignette is made much larger than the intended engraving, and it is finished with the most elaborate attention to detail. This design is then reduced, by copying on a daguerreotype plate, to the size required for the bank note.

It passes now into the hands of the engraver, who traces with a steel point on the daguerreotype plate the outlines of the picture. An impression is then taken on paper from this plate, and while the ink is still fresh the outline engraving thus obtained is laid face downward on a softened steel plate and passed through the press. The exact outline is thus transferred to this plate, which is then treated like any other line engraving. After the engraver's work is done the plate is hardened by restoring its carbon. This plate is never printed from directly, but is retained as a die, to be reproduced by the Perkins process. The cost of engraving an ordinary vignette is from $300 to $400, but large and elaborate ones are more expensive. The time required is from one to two months. The principal vignette engravers in the United States now are James Smillie, Charles Burt, Alfred Jones, W. W. Rice, F. Gursch, S. A. Schoff, Louis Del Noce, and James Bannister. There are usually from two to three vignettes on the face of a bank note, each of which is engraved originally on a separate plate. The machine work, technically called "counters," on which the denominational numbers are engraved, as well as the other lathe ornamentation, is done also on separate plates, which are hardened for dies.

A bank-note company always has on hand a large number of these dies of vignettes and other designs, and new ones are continually produced. The designs made by the various machines in use cannot be imitated excepting by similar machines, and these cannot easily be procured by counterfeiters. The lathe invented by Spencer has been perfected to a degree undreamed of by him. A first-class lathe costs about $5,000. Many of its parts are as nicely constructed as the works of a watch. It moves with the most accurate minuteness, and can be adjusted to engrave figures of almost microscopic delicacy of detail. In making new designs the operator experiments on smoked glass, which being held to the light shows the pattern produced. If satisfactory it is reproduced on soft steel, to be afterward hardened into a die. Parallel lines are engraved by the plain ruling machine, which works also with mathematical accuracy. By the medallion ruling machine any coin or medal, or any figure, whether cameo or intaglio, may be reproduced on a plane surface. This machine is not used now, as cheaper ones that will do similar work are made in Germany. The cycloidal machine invented by Cyrus Durand, now also in disuse, is capable of doing very fine work.

A machine called the "geometrical pantograph," patented in this country in 1866, is the invention of Edmund Oldham, formerly an engraver in the bank of Ireland, but now of New York. It is remarkable for its capabilities, being able to reproduce any design either of the same size as the original, larger, or smaller. Like the medallion ruling machine, it is guided by the hand. After the lathe-work patterns have been cut on the soft steel, a part of the centre of the counter large enough for the denominational figures is smoothed by erasing the design. As this portion is then a little lower than the surrounding surface, it is forced up by blows of a hammer on the back, and the figures are engraved on it by hand. The distinctive name of the bank and other large letters are also engraved by hand. In designing a new bank note, impressions from various vignettes and counters are made on paper, and the pieces are fitted together by the modeller in such a manner as to leave appropriate spaces for the lettering and signatures. When a satisfactory design is secured, the next process is to transfer the several plates which make up the note to the plate from which the notes are to be printed.

The latter is large enough usually to contain four notes, each of which is produced on it by successive rollings under the cylinders. This large plate is not hardened like the original, but is printed from in its soft state, and is capable of producing about 60,000 impressions before becoming impaired by wearing. - The printing of bank notes demands extreme care at every step. The ink must be nicely ground and mixed, and of the finest quality. Formerly the best black ink was made from Frankfort black, a charcoal obtained from grape and vine lees, peach kernels, and bone shavings; but now it is usually prepared by calcining sugar in an air-tight iron vessel. If the notes were printed in black alone, they could easily be reproduced by photography. To guard against this, many devices have been employed. At one time several colors were used, but it was found that all the tints could be removed chemically from the paper without destroying its texture. At last a green ink was invented, made from the anhydrous sesquioxide of chromium, which filled the required conditions; it could not be removed without destroying the black ink with it. This practically prevents counterfeiting by photography, for green acts the same as black on the photographic plate.

This green ink was used for several years in printing the United States money, but it was finally discarded because it wore down the plates so fast that it increased largely the cost of producing the notes. When different colors are used, separate plates are required for each tint, only one of which is printed at a time. A good workman can make from 500 to 000 impressions in a day, whereas by the electrotype process of the bank of England 3,000 can be produced in an hour. After printing, the notes are dried by artificial heat in the drying room. This process, which formerly required a week, is now accomplished in a few hours. They are then smoothed between pasteboards by hydrostatic pressure. - To lessen the tedious mechanical operations connected with engraving, attempts have been made to obtain directly from the drawings, by chemical means, engraved daguerreotypes and photographic negatives for printing. Various processes have been devised, both in the United States and in Europe, to effect this object, some of which have met with a good measure of success. (See Photography.)