Besides the simpler arrangements of the materials, as in the roll, tablet, or leaf, there were arrangements of the material more resembling the book form of to-day, as in the diptych and the triptych. The _diptych_ was made of two tablets of wood or of other material and resembled our double slates, having the tablets for the writing sunken below the protecting edges. These were hinged together and covered on their protected sides with a coating of wax. On this wax surface the Greeks and Romans wrote with a stylus. The writing could easily be obliterated by simply melting the wax, when it became a prepared plate for another inscription. The _triptych_ and the _polyptych_, as the respective words suggest, consisted of three or four or more leaves hinged together and made available for literary or other inscriptions, after the manner of the diptych. XII INKS Any reference to the literary productions of the past and to the materials preserving and perpetuating written records, including the Bible and sacred history, would be deficient were the qualities of the early inks disregarded. The very ink in which the ancient literature, sacred and classic, was embodied had an importance scarcely, if any, less than the materials upon which the writing was impressed or recorded. The task of transcribing a book, _e. g._, the Gallic Wars, the Epic of Virgil, or the Bible, was an undertaking of so great magnitude that the conservation of energy, if nothing else, taught the importance of securing and using an ink that had "staying" qualities. No sensible person, no matter when or where he might live, would be apt to spend the time required to copy the Bible in its entirety (a task necessitating the labor of a skillful calligraphist for nearly three years) when all his work would soon be wasted by reason of an impermanent ink. The makers of the inks used in the early ages had a skill and knowledge in the mixing of pigments or in compounding the ingredients of their inks undiscovered, as yet, and unequaled in modern times. The superiority of the inks known to the ancients has long been the object of surprise and admiration. The inscriptions on mummy-cases, made at a time long antedating the Christian Era, and the writing on manuscripts made in the early centuries of Christian history, in addition to the beauty of the form and finish of the writing, have a freshness of appearance as though they were only of years' instead of centuries' duration. "The survival of papyrus rolls containing the text of the Egyptian ritual known as 'The Book of the Dead,' dating back fifteen centuries B. C., and accompanied with numerous scenes painted in brilliant colors, proves how ancient was this very natural method of elucidating a written text by means of pictures."[36] And among the ancient archæological treasures recently discovered in Crete are stucco designs, the colors of which are almost as brilliant as when laid on, over three thousand years ago.