Moreover as papyrus manuscripts were only written on one side of the paper, the back was free to receive new writing without any necessity to rub out the original text. The recently discovered treatise by Aristotle on the _Political Constitution of Athens_ has some monetary accounts written on the back of the papyrus by some unphilosophical man of business not many years later than the date of the original treatise.
_Papyrus paper._ The ancient methods employed in the preparation of papyrus paper (_charta_) can be clearly made out by the evidence of existing examples aided by the minute but not wholly accurate description given by Pliny, _Hist. Nat._ XIII. 71 to 83.
The papyrus plant, the _Cyperus Papyrus_ of Linnaeus, (Greek [Greek: byblos]) is a very tall, handsome variety of reed which grows in marshes and shallows along the sides of streams of water. The plant has at the top a very graceful tufted bunch of foliage; its stem averages from three to four inches in diameter, and the total height of the plant is from ten to twelve feet.
It grows in many places in Syria, in the Euphrates valley and in Nubia. In Egypt itself it is now extinct, but it was abundant there in ancient times, especially in the Delta of the Nile.
The only spot in Europe where the papyrus plant grows in a wild state is near Syracuse in the little river Anapus, where it was probably introduced by the Arab conquerors in the eighth or ninth century A.D.
It grows here in great abundance and sometimes nearly blocks up the stream so that a boat can scarcely get along.
The stem of the papyrus consists of a soft, white, spongy or cellular pith surrounded by a thin, smooth, green rind. Papyrus paper ([Greek: biblia] or [Greek: chartês]) was wholly made from the cellular pith. The method of manufacture was as follows.
The long stem of the plant was first cut up into convenient pieces of a foot or more in length; the pith in each piece was then very carefully and evenly cut with a sharp knife into thin slices. These slices were then laid side by side, their edges touching but not overlapping, on the smooth surface of a wooden table which was slightly inclined to let the superfluous sap run off, as it was squeezed out of the slices of pith by gentle blows from a smooth wooden mallet. When by repeated beating the layer of pith had been hammered down to a thinner substance, and a great deal of the sap had drained off, some fine paste made of wheat-flour was carefully brushed over the whole surface of the pith. A second layer of slices of pith, previously prepared by beating, was then laid crosswise on the first layer made adhesive by the paste, so that the slices in the second layer were at right angles to those of the first. The beating process was then repeated, the workmen being careful to get rid of all lumps or inequalities, and the beating was continued till the various slices of pith in the two layers were thoroughly united and amalgamated together.