CELLULOSE

forms the chief component of vegetable cell wall and hence of all vegetable ti ues, and is the product of the vital activity of plants in building up their structure from carbon dioxide and water. It is, in chemical constitution, a carbohydrate representable by the formula (CsH1i.0;)n, and is obtainable pure from cotton or linen fibre by boiling out impurities with alkali, alcohol, or ether. Cotton, linen, and ordinary filter paper are nearly pure forms of cellulose. Itis a white opaque substance appearing under microscope as a fretwork of thin flattened tubes, is insoluble in water, alcohol, ether, and di olves in an ammoniacal solution of copper hydroxide. It yields a blue color when treated with strong sulphuric acid, and if then diluted with water and boiled is converted into dextrose (grape sugar). Unsized paper dipped into strong sulphuric acid is converted into ‘parchment paper’ or ‘vegetable parchment.’ Strong nitric, or preferably nitro-sulphuric, acid converts it, after being dried, into inflammable nitrates, made use of in gun cotton, collodion, celluloid, etc. Cellulose treated first with caustic soda and then with carbon disulphide produces a thick brown syrup called ‘viscose,’ from which artificial silk is manufactured commercially. Besides being the source of valuable derivatives, cellulose itself is used in the fibrous state as cotton, linen, hemp, and jute in textile industries, and as a pulp, obtained from wood or esparto gra , in paper making. physicist; prof. of Astronomy, Upsala, 1730-44; measured arc of the meridian in Lapland; devised the centigrade thermometer.