8. Plates of steel will yield near ten times as many good impressions as those of copper, and this too without being hardened. Besides, an engraving on steel may be transferred to a softened steel cylinder, in such a manner that the lines may stand in relief; and this cylinder, after having been hardened, may be brought in forcible contact with another plate, and thus the design may be multiplied at pleasure. 9. The bank-note engravers have now a great variety of designs and figures on steel rollers, which they can easily transfer to new plates. This practice, as applied to plates for bank-notes, originated with Jacob Perkins. It is supposed that he must have been led to it by an English engraver in his employ, who may have explained to him the manner in which the British calico-printers produced engravings on copper cylinders. This is not altogether improbable, since the principle in both cases is substantially the same. 10. In consequence of the increased demand for maps and pictorial embellishments in books, as well as for single prints as ornaments for rooms, engraving and copperplate-printing have become employments of considerable importance; and these arts must doubtless continue to flourish to an indefinite extent, in a country where the taste for the fine arts is rapidly improving, and where wealth affords the means of liberal patronage. [Illustration: LITHOGRAPHER.] THE LITHOGRAPHER. 1. The word _lithography_ is derived from two Greek words--_lithos_, a stone, and _grapho_, to write; and the art to which the term is applied has reference to the execution of letters, figures, and drawings, on stone, and taking from them fac-simile impressions. The art is founded on the property which stone possesses, of imbibing fluids by capillary attraction, and on the chemical repulsion which oil and water have for each other. 2. Every kind of calcareous stone is capable of being used for lithography. Those, however, which are of a compact, fine, and equal grain, are best adapted to the purpose. The quarries of Solenhofen, near Pappenheim, in Bavaria, furnished the first plates, and none have yet been found in any other place, to equal them in quality; although some that answer the purpose tolerably well, have been taken from quarries in France and England. 3. In preparing the stones for use, they are first ground to a level surface, by rubbing two of them face to face, sand and water being interposed. Then, if they are designed for _ink drawings_, they are polished with pumice-stone; but, if for _chalk drawings_, with fine sand, which produces a grained surface adapted to holding the chalk.