At a later period, not determinable, the papyrus writing material was no longer made up into roll form but was cut into rectangular sheets of various dimensions, according to the taste of the writer or the special need, and was then bound together somewhat as a modern book. Sometimes, when greater durability was sought, the writer or copyist would insert a leaf of parchment at every five or six leaves of the papyrus. This added greatly to the durability of the book. There are examples of books thus "reinforced" which have resisted the destructive influences of time and use for twelve centuries together. The fragile and extremely perishable character of the papyrus makes it most remarkable that any writing thereon should have survived for centuries; indeed, according to Pliny, a volume two centuries old was considered so exceptional as to be almost incredible. It was the perishable character of this material that made the frequent renewal of manuscripts handled a constant necessity, and hence the occupation of the copyists and the department of reproduction in the libraries were logical. The fragile character of the papyrus led, also, to the frequent use of a wooden case, called a _capsa_, to protect and preserve the roll. It was under very exceptional conditions only, as in mummy-cases of Egyptian tombs where they escaped the touch of man and, almost, the touch of time as well, and, as hermetically sealed under lava beds at Pompeii and Herculaneum, that the fragile papyrus was sometimes preserved for centuries. The earliest known papyrus manuscripts date from the time of the twelfth dynasty of Egypt, or from a period of more than two thousand years before the Christian Era began. These oldest existing papyrus documents yet discovered are written in Egyptian--in three characters--in _hieroglyphics_, the most ancient or the picture-writing of the earliest times (translatable by the decipherment of the Rosetta Stone), in the _hieratic_, or the writing of the priests of Egypt from the period of the fourth or fifth dynasty (3124-2744 B. C., Lepsius) on to the third or fourth century of the Christian Era, and in the _demotic_, or the later and popular form of the priestly writing. In general, however, the papyrus period of the Egyptian literature extended from the fourth century B. C. to the fourth century A. D. The extensive use of the papyrus as writing material is evidenced in the fact that an important commerce therein extended over a large part of the civilized world as early as the third century B. C., and continued to be a source of wealth to the Egyptians for centuries after the Christian Era had begun. In fact the use of papyrus continued, although interrupted greatly by the Saracen conquest and the embargo laid upon its importation into Pergamum by the Ptolemaic rulers of Egypt, until it was superseded by the manufactured paper as it progressively came into use. (Isaac Taylor.) X PAPER AND ITS MANUFACTURE