From this period, the succession and progress of the art is clearly to be traced. First, through figure blocks, with letterings sculptured on them in relief, to solid blocks carved in wood and printing off entire pages, as is done by modern stereotypes, with or without pictures attached. At this stage of the work the idea of reproduction and multiplication had obtained as the primary objects of the art. The next step was the invention of movable types capable of being combined at will into words and sentences, braced into the form of pages, and, the work completed, distributed, and combined anew for the composition of other and different works. From this period, wood-engraving proper, and type-cutting in wood, became separate arts; and ere long--metallic types engraved at first, and afterward cast, replacing the wooden letters--the latter passed into oblivion, while the former has increased gradually and steadily, though with occasional pauses and interruptions, until the present day; when it has attained its highest known perfection, while it is still so far progressive, that it is not easy to predict what may be expected of its future improvement and excellence. And here it may be well, since few persons comparatively speaking, even of those who are admirers and more or less judges of the art, have a distinct idea of its precise character and nature, to explain briefly in what it consists and wherein it differs from engraving on copper or steel. All engraving consists of cutting with a sharp instrument into a hard surface, whether of wood or metal, so that when the picture is perfected on the wood or metal, ink may be applied to the surface, from which fac-similies may be taken off by the impression of moistened paper on the block or plate by means either of friction or pressure. The practice thus far is identical whether steel, copper or wood is to be the material engraved. But with this all similarity ends. In steel or copperplate-engravings the ink, when applied, is received into the engraved lines, and is wiped off from the prominent portions; so that, in the impressions taken on paper, the lines cut into the plate communicate the shades, the portions left in relief on the plate remain colorless and blank. In wood-engravings, on the contrary, the ink, when applied, is taken up by the parts left prominent, and never penetrates into the engraved lines; so that, in the impressions taken on paper, the portions of the wood less prominent communicate the shades, the portions cut away, on the block, remain colorless and blank. Thus the same process, pursued on the metallic plate, and on the wood-block, produces effects diametrically opposite, and to produce the same effects from the two materials converse processes must be pursued. Thus we will engrave the word [Illustration: =Printing=]