PALIMPSEST. The custom of removing writing from an inscribed surface, and thus preparing that surface to receive another text, is an old one. The term palimpsest (from Gr. raXcv, again, and 1(aco, I scrape) is used by Catullus and Cicero, refer ring, respectively, to papyrus ( ?) and waxen tablets; and by Plutarch, who tells of Plato comparing Dionysius to a as his tyrant nature, being boryborXtyros, showed like imperfectly erased writing. The reference here is clearly to washing writing off papyrus. IIaXiinkricrros can only at first have been applied to mss. of a material strong enough to bear actual scraping or rubbing, as at first to waxen tablets and vellum books. There are still some tablets surviving with traces of earlier writing under a fresh layer of wax. Papyrus could not be scraped or rubbed; writing was sponged from it. This could not be very cleanly done, so the material was only re-used for unimportant documents. Earlier writing is seldom detected in extant papyri no doubt because of the abundant supply of that material.
In the early period of palimpsests, vellum mss. were washed, not scraped. In course of time, e.g., by atmospheric action, the origi nal writing would partly reappear; thus many capital and uncial palimpsests have been successfully deciphered. In the later middle ages vellum surface was scraped away ; the reading of the later examples is therefore often impossible. Besides actual rasure, there were various recipes for effacing writing, e.g., to soften the surface with milk and meal, and then to rub with pumice. To bring out the original writing various chemical reagents have been tried. The old method of smearing with tincture of gall ultimately rendered the text illegible. Of modern reagents the most harmless appears to be hydrosulphate of ammonia; but this also needs caution.
The custom of re-using vellum mss. arose primarily from dearth of material. In the case of Greek mss. so great was the consump tion of old codices that a synodal decree (A.D. 691) forbade the
destruction of intact mss. of the Scriptures or the church Fathers. The decline of the vellum trade on the introduction of paper inten sified the scarcity. Vast destruction of the broad quartos of the early centuries of our era took place after the fall of the Roman empire, so the most valuable Latin palimpsests are found in vol umes remade from the 7th to the 9th centuries. No entire work has been found in the original text of a palimpsest, but portions of many works were used to form a volume. This proves that scribes made use of any suitable material available.
An enumeration of the different palimpsests of value is not here possible (see Wattenbach, Schriftwesen, 3rd. ed. pp. 299-317) but a few may be mentioned of which facsimiles are accessible. The ms. in the Bibliotheque Nationale, Paris, known as the Codex Ephraemi, containing portions of the 0. and N. testaments in Gr. ( ? 5th century) is covered with works of Ephraem Syrus in a hand of the 12th century (ed. Tischendorf, 1843, 1845). Among the Syriac mss. from the Nitrian desert in Egypt, now in the British Museum, some important texts have been recovered. A volume containing a work of Severus of Antioch of the 9th century is written on palimpsest leaves taken from mss. of the Iliad, and the Gospel of St. Luke, both of the 6th century (Cat. Anc. Mss. vol. i. pls. 9, io), and the Elements of Euclid of the 7th or 8th cen tury. To the same collection belongs the double palimpsest, in which a text of St. John Chrysostom, in Syriac, of the 9th or ioth century covers a Latin grammatical treatise of the 6th century, which in its turn has displaced the Latin annals (5th century) of Granius Licinianus. For Latin palimpsests also see the Exempla of Zangemeister and Wattenbach. By using skill and judgment, photography may be often made a useful agent in the decipher ment of obscure palimpsest texts.