Among ancient writers, Pliny gives the fullest description of the preparation of papyrus, in his _Historia Naturalis_, xiii. 11.[34] The sheets were prepared, not from the bark, but from the pith of the plant. This was cut into strips (σχίδας) as thin and broad, and, according to some, as long as possible. These were laid side by side as firmly as might be, to form the first layer (σχέδα). On this a second layer was laid crosswise and fastened to the lower with moisture or gum. The two layers were then compressed to form the writing sheet (σελίς), which was carefully dried and polished with ivory or a smooth shell. The roll (τόμος, κύλινδρος) consisted of a number of σελίδες joined together to make one long strip—sometimes as much as 20 or 40 feet long, or even longer. The upper side, the side used for writing on, was the one in which the fibres ran in a horizontal direction parallel to the edge of the roll.[35] The under or outer side was only used in cases of necessity.[36] The first sheet (πρωτόκολλον) was made stronger than the rest, and its inner edge was glued to a wooden roller (ὄμφαλος), with a knob at the end (κέρας). The margin of the roll, what corresponds to the edge of our books, was frequently glazed and coloured, while the back was protected against worms and moths by being rubbed with cedar oil. The title was inscribed on a separate label of parchment (σίττυβος or σίλλυβος). The separate rolls were enclosed in a leather case (διφθέρα or φαινόλης, see 2 Tim. iv. 13), and a number of them kept in a chest (κιβωτός or κίστη). On the literature cf. also Paul Krüger, _Ueber die Verwendung von Papyrus und Pergament für die juristische Litteratur der Römer_, Zeitschrift der Savigny-Stiftung für Rechtsgeschichte. Roman section, viii. pp. 76-85 (1887). Wilcken, _Archiv für Papyrus-Forschung und verwandte Gebiete_, Leipzig, Teubner. F. G. Kenyon, _Palaeography of Greek Papyri_. C. Haeberlin, _Griechische Papyri_, Leipzig, 1897: “Nearly 150 years have fled since 432 complete Rolls and 1806 Papyrus Fragments were discovered in the year 1752 at Herculaneum, in the Villa of L. Calpurnius Piso Caesoninus, the pupil and friend of the Epicurean philosopher Philodemus. Then twenty-five years later the soil of Egypt, that home and nursery of literature, opened for the first time to vouchsafe to us a Greek Papyrus Roll, destined to be the forerunner of a series of discoveries often interrupted but never ceasing altogether. It was, perchance, not the only one of its kind; but out of the fifty rolls accidentally discovered in the year 1778 by Arabian peasants in the neighbourhood of Memphis, it alone had the fortune to come into the possession of Cardinal Stefano Borgia. The rest were burned by their unsuspecting discoverers, who found a peculiar pleasure in the resinous odour that arose from their smoking pyre.” Paper.