352 THE UNIVERSE. 



gaze works which go back to the days of the Pharaohs. 

 The paper-sedge (Cyperus papyrus), which has such a 

 strange aspect, and which grows on the banks of the Nile, 

 has long been understood to furnish this precious object. 1 



The wood is composed of concentric zones, lying one 

 within the other, which are the result of the intimate union 

 of a mass of microscopic vessels and fibres. 



In the centre of the stem is found the pith, composed al- 

 most exclusively of cellular tissue. It is with very thin 

 sheets of this structure, cut by means of a sharp knife, that 

 the Chinese make the beautiful paper on which they paint, 

 and which is incorrectly called rice-paper. 2 



The second type of stem belongs to the palms. This stem, 

 which bears the name of stipes, is usually cylindrical, and is 

 without branches or bark. 3 



1 The employment of the papyrus for writing upon seems to have preceded his- 

 toric times. Herodotus asserts that he saw drawn up on this substance a cata- 

 logue of 330 kings who had preceded Sesostris. Papyrus was employed even in 

 Gaul up to the beginning of the seventh century ; and to preserve the manuscript 

 books, after every four or five leaves of paper two leaves of vellum were placed, 

 on which the text was continued. In the end the papyrus was replaced by cot- 

 ton-paper, cliarta bombycina, also called charta damascena. The invention of rag- 

 paper, which M. Goury ascribes to about the twelfth century, probably caused 

 the disuse of cotton-paper. 



2 Rice-paper is nothing else than fine layers, cut with great skill, of the pith of 

 the JEschynomene paludosa, a plant of the family of the Leguminosae. 



8 This sort of stem has no distinct concentric layers or medullary rays. The 

 youngest formation takes place towards the centre instead of at the circumference, 

 as in exogens ; and the pith p (Fig 163) does not occupy the centre, but is in- 

 terposed between bundles of woody and vascular tissue, f, which descend from 

 the leaves, and, curving inwards, pass down near the middle of the stem for some 

 distance, as shown in Fig. 164, and then, taking an outward course, terminate at 

 the circumference. The older formations, being thus continually pressed out- 



