3. At length, larger subjects, with inscriptions in imitation of manuscript, were executed. The success of these prints gave rise to a more extensive application of the art. Scriptural subjects, of many figures, with texts of scripture, were engraved, and impressions were taken from them on one side of the paper, two sheets being pasted together to form a leaf. Entire sets were bound up together, and thus were formed the first printed books, which, being produced entirely from wood-cuts, are known by the name of _block-books_. These books made their appearance about the year 1420. 4. One of the earliest of these productions is denominated "The Apocalypse of St. John;" another, "The Poor Man's Bible." But one of the latest and most celebrated, is called "The Mirror of Salvation," published in 1440. Part of the text was printed from solid blocks, and part, from moveable wooden types. From this fact, it is easy to discover the origin of printing. After this, most, if not all, of the books, were printed from moveable types; but, as they were embellished with wood cuts, the demand for such engravings was very much increased, although they were, at first, by no means elegant. 5. Near the close of the fifteenth century, the art began to assume a higher character, principally by the talents of Michael Wolgermuth and William Pluydenwurf. Albert Durer made still greater improvements, and, in 1498, published his celebrated Apocalypse of St. John, printed from folio blocks. Other celebrated engravers succeeded him in the sixteenth century, which may be considered the era when wood engraving was at its highest point of elevation. After this, the art declined, and was considered of little importance, until it was revived in 1775, by the distinguished William Bewick, of Newcastle, England. It is still practised, especially in England and the United States, in a manner which reflects credit on the ingenuity of the age. 6. The earlier artists operated on various kinds of wood, such as the apple, pear, and beech; but these, being too soft, are now used only for calico-printing and other common purposes. Box-wood, on account of its superior texture, is used for every subject that can be termed a work of art. That from Turkey is the best. 7. The engravers, in the infancy of the art, prepared the wood as the common block-cutters now do. The tree was cut the way of the grain, in planks, and of course they engraved on the side of the grain, as upon a board. This mode of preparation enabled them to execute larger subjects. The engravers now prefer the end of the grain, and therefore cut the log transversely.