Fig. 19.—Thibetan prayer wheel.
But writing of this last kind on rolls has suggested another arrangement in which the reading is more easy, and the re-rolling of the roll itself avoided.
It will be seen that a blank space is left between each of the written “pages.” Now if the vellum, bark, or paper be folded across these vacant spaces, one after the other, backwards and forwards, like accordion pleating, we shall find that we get a form of book well known in the East and also among primitive nations.
Fig. 20.—Roll written upon in page form.
Curious examples of such converted rolls can be seen in most museums, and they are generally kept flat by means of two boards front and back, but not otherwise fastened.
The Chinese and Japanese have taken this particular form of evolution from the roll to the book a step further, and by help of the ancient device of “stabbing” the flattened roll along one of its sides, they produce a form called an “Orihon,” easy to consult, strong, and the blank back of the roll so hidden up that its existence is frequently not realised. But if some of the leaves of an Orihon are cut, its real structure becomes at once evident, and a book will be produced with letterpress and blank paper alternately in pairs. A similar kind of alternation shows now and then in the case of MS. rolls that have been cut up, but they are oftener arranged letterpress and blank alternately.
Fig. 21.—Sumatran bark book in the form of a folded roll.