In the complete styles of engraving, stipple, line, and mezzotint, although American engravers are little known out of their own country--a large enough field, however, in which to exercise their talents--some good work has also been done; in stipple, by David Edwin, Ion. B. Forrest, Gimbrede, and C. Tiebout; in mezzotint, by Charles Wilson Peale, A. H. Ritchie, and John Sartain, who, after having worked under the direction of William Young Ottley, went from London to America in 1830 at the age of twenty-two; and in line, by Asher Brown Durand; Joseph Andrews; the Smillies; and Charles Burt, who is said to have been the actual engraver of the fine plate of Leonardo's "Last Supper," copied from Morghen's print of the same subject, and bearing the name of A. L. Dick as engraver. The lives of these and others not mentioned were often eventful and picturesque, and would repay study. Some leaving England, Scotland, or Ireland in early life to settle in the land of their adoption, had to struggle with difficulties, often teach themselves, make their own tools, like John Cheney, or like Charles Wilson Peale, turn their hands to whatever duty might present itself. Peale was a captain of volunteers, dentist, lecturer on natural history, saddler, watchmaker, silversmith, painter in oil, crayons, or in miniature on ivory, modeller in clay and wax, engraver in mezzotint, and to crown all, as his son was wont to say, a mild, benevolent, and good man. Many also devoted their talents to bank-note engraving, a branch of the art highly cultivated in the United States, in which the skill of the inventor and mechanic has been united with the grace and genius of the artist. As engravers in this particular style may be specially mentioned W. E. Marshall, J. W. Casilear, M. J. Danforth, Gideon Fairman, and Jacob Perkins, the latter of whom, with Fairman and the ingenious Asa Spencer, came over to England in 1818 to compete for the premium of £20,000 offered by the Bank of England for a bank-note which could not be counterfeited. Although not successful, the Bank allowed them the sum of £5,000 in consideration of their ingenuity and the trouble and expense which they had incurred in the matter. While Asa Spencer is to be credited with inventing the method of applying the geometric lathe[72] to engraving the involved patterns on banknotes, Perkins has the honour of introducing the process of transfer by means of steel rollers. The portrait or other design is engraved in the usual manner on a die plate, which is then hardened; a soft steel roller or cylinder is now rolled over the die with great pressure by means of a powerful machine, causing the cylinder to take off in its course the impression of the design in relief; this roller is now hardened in its turn, and by the use of similar means made to impress another soft steel die; by repeating this process, any requisite number of plates can thus be reproduced the exact fac-similes of the original engraved die plate.