GORI, A. F.--Thesaurus reterum diptychorum consularium et ecclesiasticorum. _Florentiae_, 1759. HARLAND, J.--_The Reliquary_, Jan., 1865. (Clog almanacks.) LABARTE, J.--Histoire des Arts Industrielles au moyen age. (Diptychs.) _Paris_, 1864-66. LACROIX, P.--Les arts au moyen age. (Diptychs.) _Paris_, 1809. LUBBOCK, SIR J.--Prehistoric Times. _London_, 1865. MADAN, F.--Books in Manuscript. _London_, 1893. MASKELL, W.--Ivories Ancient and Mediæval. _London_, 1875. MASKELL, A.--Ivories. _London_, 1904. PLOTT, R.--Natural History of Staffordshire. (Clog almanacks.) _Oxford_, 1686. PRESCOTT, W. H.--History of the Conquest of Peru. (Quipus.) _London._ REINAUD.--(Description des monumens Musulmanes du cabinet de M. le Duc de Blacas.) (Indian amulets.) _Paris_, 1828. RIVETT-CARNAC, J. H.--Prehistoric Remains in Central India. _Calcutta._ RIVETT-CARNAC, J. H.--Ancient Rock Sculptures in Kamaon. _Calcutta_, 1877. SIMPSON, SIR J. Y.--Archaic Sculpturings. _Edinburgh_, 1867. SMITHSONIAN REPORT, 1879, p. 389. (Wampum.) TAVERNIER, J. B.--Voyages. _Paris_, 1810. TAYLOR, I.--The Alphabet. _London_, 1883. THOMPSON, SIR E. M.--Handbook of Greek and Roman Palæography. _London_, 1893. WESTWOOD, J. O.--Cat. of Fictile Ivories. _London_, 1876. CHAPTER II. ROLLS, BOOKS AND BOOKBINDINGS. Rolls of papyrus and vellum--Quaternions--The sewing of books--Headbands--The rounding and backing of books--Mediæval books--Irish cumdachs--Byzantine bindings--Oriental books--Modern methods of sewing and binding. The length of ancient rolls of vellum has often puzzled bibliophiles. Rolls of narrow breadth are found 16 or 17 feet or more in length. A learned scholar on being asked how he accounted for this extraordinary length was quite puzzled, never having realised that the roll was in one piece. The neck of the giraffe seemed the only possible solution. [Illustration: FIG. 16.--Egyptian papyrus roll, with mud seals.] The writer however consulted a clever leather worker and gave him a skin measuring about 3 feet by 2, suggesting certain ways of cutting it. He produced eventually, by wetting, pulling and pinning, a beautiful roll of nearly 4 inches in breadth and 16 feet 9 inches in length. Mediæval leather workers were no doubt more skilled and practised in this particular art than anyone now is, and the experiment showed that there is really nothing out of the way in the very long rolls which at first sight seem so surprising. Rolls were written upon in three ways. In the oldest rolls the usual way was to write lines across the breadth of the roll, which was held upright before the reader, and unrolled from the top downwards. [Illustration: FIG. 17.--Roll written upon across its shorter diameter.]