PALIMPSEST. The custom of removing writing from the surface of the material on which it had been inscribed, and thus preparing that surface for the reception of another text, has been practised from earliest times. The term palimpsest (from Gr. πάλιν, again, and ψάω, I scrape) is used by Catullus, apparently with reference to papyrus; by Cicero, in a passage wherein he is evidently speaking of waxen tablets; and by Plutarch, when he narrates that Plato compared Dionysius to a βιβλίον παλίμψηστον, in that his tyrant nature being δυσέκπλυτος, showed itself like the imperfectly erased writing of a palimpsest MS. In this passage reference is clearly made to the washing off of writing from papyrus. The word παλίμψηστος can only in its first use have been applied to MSS. which were actually scraped or rubbed, and which were, therefore, composed of a material of sufficient strength to bear the process. In the first instance, then, it might be applied to waxen tablets; secondly, to vellum books. There are still to be seen, among the surviving waxen tablets, some which contain traces of an earlier writing under a fresh layer of wax. Papyrus could not be scraped or rubbed; the writing was washed from it with the sponge. This, however, could not be so thoroughly done as to leave a perfectly clean surface, and the material was accordingly only used a second time for documents of an ephemeral or common nature. To apply, therefore, the title of palimpsest to a MS. of this substance was not strictly correct; the fact that it was so applied proves that the term was a common expression. Traces of earlier writing are very rarely to be detected in extant papyri. Indeed, the supply of that material must have been so abundant that it was hardly necessary to go to the trouble of preparing a papyrus, already used, for a second writing.
In the early period of palimpsests, vellum MSS. were no doubt also washed rather than scraped. The original surface of the material, at all events, was not so thoroughly defaced as was afterwards the case. In the course of time, by atmospheric action or other chemical causes, the original writing would to some extent reappear; and it is thus that so many of the capital and uncial palimpsests have been successfully deciphered. In the latter middle ages the surface of the vellum was scraped away and the writing with it. The reading of the later examples is therefore very difficult or altogether impossible. Besides actual rasure, various recipes for effacing the writing have been found, such as to soften the surface with milk and meal, and then to rub with pumice. In the case of such a process being used, total obliteration must almost inevitably have been the result. To intensify the traces of the original writing, when such exist, various chemical reagents have been tried with more or less success. The old method of smearing the vellum with tincture of gall restored the writing, but did irreparable damage by blackening the surface, and, as the stain grew darker in course of time, by rendering the text altogether unintelligible. Of modern reagents the most harmless appears to be hydrosulphate of ammonia; but this also must be used with caution.
The primary cause of the destruction of vellum MSS. by wilful obliteration was, it need hardly be said, the dearth of material. In the case of Greek MSS., so great was the consumption of old codices for the sake of the material, that a synodal decree of the year 691 forbade the destruction of MSS. of the Scriptures or the church fathers—imperfect or injured volumes excepted. The decline of the vellum trade also on the introduction of paper caused a scarcity which was only to made good by recourse to material already once used. Vast destruction of the broad quartos of the early centuries of our era took place in the period which followed the fall of the Roman Empire. The most valuable Latin palimpsests are accordingly found in the volumes which were remade from the 7th to 9th centuries, a period during which the large volumes referred to must have been still fairly numerous. Late Latin palimpsests rarely yield anything of value. It has been remarked that no entire work has been found in any instance in the original text of a palimpsest, but that portions of many works have been taken to make up a single volume. These facts prove that scribes were indiscriminate in supplying themselves with material from any old volumes that happened to be at hand.
An enumeration of the different palimpsests of value is not here possible (see Wattenbach, Schriftwesen, 3 rd ed., pp. 299–317); but a few may be mentioned of which facsimiles are accessible. The MS. in the Bibliothèque Nationale, Paris, known as the Codex Ephraemi, containing portions of the Old and New Testaments in Greek, attributed to the 5th century, is covered with works of Ephraem Syrus in a hand of the 12th century (ed. Tischendorf, 1843, 1845). Among the Syrian MSS. obtained from the Nitrian desert in Egypt, and now deposited in the British Museum, some important Greek texts have been recovered. A volume containing a work of Severus of Antioch of the beginning of the 9th century is written on palimpsest leaves taken from MSS. of the Iliad of Homer and the Gospel of St Luke, both of the 6th century (Cat. Anc. MSS. vol. i., pls. 9, 10), and the Elements of Euclid of the 7th or 8th century. To the same collection belongs the double palimpsest, in which a text of St John Chrysostom, in Syriac, of the 9th or 10th century, covers a Latin grammatical treatise in a cursive hand of the 6th century, which in its turn has displaced the Latin annals of the historian Granius Licinianus, of the 5th century (Cat. Anc. MSS. ii., pls. 1, 2). Among Latin palimpsests also may be noticed those which have been reproduced in the Exempla of Zangemeister and Wattenbach. These are—the Ambrosian Plautus, in rustic capitals, of the 4th or 5th century, re-written with portions of the Bible in the 9th century (pl. 6); the Cicero De republica of the Vatican, in uncials, of the 4th century, covered by St Augustine on the Psalms, of the 7 th century (pl. 17; Pal. Soc., pl. 160); the Codex Theodosianus of Turin, of the 5th or 6th century (pl. 25); the Fasti Consulares of Verona, of A.D. 486 (pl. 29); and the Arian fragment of the Vatican, of the 5th century (pl. 31). Most of these originally belonged to the monastery of Bobbio, a fact which gives some indication of the great literary wealth of that house. By using skill and judgment, with a favouring light, photography may be often made a useful agent in the decipherment of obscure palimpsest texts.(E. M. T.)