With the exception of such few modifications as characterise prints in the scraped or scratched manner, called "sgraffio," and in the stippled manner, the methods of engraving just mentioned are all that have been used in Europe from the end of the Middle Ages up to about the second half of the seventeenth century. We need not, therefore, at present mention more recent processes, such as mezzotint, aquatint, &c., each of which we shall touch upon at its proper place in the history of the art. Before proceeding with this history, let us try to recollect the facts with which we have prefaced it; and, as chronological order proscribes, to differentiate and classify the first productions of relief engraving. However formal their differences of opinion on matters of detail, technical writers hold as certain one general fact. They all agree in recognising that the methods of relief engraving were practised with a view to printing earlier than the method of intaglio. What interval, however, separates the two discoveries? At what epoch are we to place the invention of wood engraving? or if the process, as has been often alleged, is of Asiatic origin, when was it brought into Europe? To pretend to give a decisive answer to these questions would be, at least, imprudent. Conjectures of every sort, and even the most dogmatic assertions, are not wanting. But the learned have in vain evoked testimony, interpreted passages, and drawn conclusions. They have gone back to first causes, and questioned the most remote antiquity; they have sometimes strangely forced the meaning of traditions, and have too often confounded simple material accidents with the evidences of conscious art properly so called. Yet the problem is as far from solution as ever, and, indeed, the number and diversity of opinions have up till now done little but render conviction more difficult and doubt more excusable. Our authorities, for instance, are not justified in connecting the succession of modern engravers with those men who, "even before the Deluge, engraved on trees the history of their times, their sciences, and their religion."[2] Nor is the mention by Plutarch of a certain almost typographical trick of Agesilaus, King of Sparta, excuse enough for those who have counted him among the precursors of Gutenberg. It is by no means impossible that Agesilaus, in a sacrifice to the gods on the eve of a decisive battle may have been clever enough to deceive his soldiers, by imprinting on the liver of the victim the word "Victory," already written in reverse on the palm of his hand. But in truth such trickery only distantly concerns art; and if we are to consider the Greek hero as the inventor of printing, we must also allow that it has taken us as long as eighteen centuries to profit by his discovery.