The paper making fibres are shown to fall into a scheme of classification based on chemical constitution, and consisting of the four groups: (a) Cotton [flax, hemp, rhea], (b) wood celluloses, (c) esparto, straw, and (d) lignocelluloses. Papers being exposed to the natural disintegrating agencies, more especially oxygen, water (and hydrolysing agents generally), and micro-organisms, the relative resistance of the above groups of raw materials is discussed as an important condition of value. The indirect influence of the ordinary sizing and 'filling' materials is discussed. The paper-making quality of the fibrous raw materials is also discussed, not merely from the point of view of the form and dimensions of the ultimate fibres, but their capacity for 'colloidal hydration.' This is complementary to the action of rosin, i.e. resin acids, in the engine-sizing of papers; and the proof of the potency of this factor is seen in the superior effects obtained in sizing jointly with solutions of cellulose and, more particularly, viscose and rosin. Wurster's much-cited monograph of the subject of rosin-sizing ['Le Collage des Papiers,' Bull. Mulhouse, 1878] neglects to take into consideration the contribution of the cellulose hydrates to the total and complex sizing effect, and hence gives a partial view only of the function of the resin acids. In further illustration of fundamental principles various developments in the textile industries are discussed, e.g. the bleaching of jute, cotton, and flax, and special developments in the spinning of rhea and flax. The concluding lecture deals with later progress in the industrial applications of cellulose derivatives, chiefly the sulphocarbonate (viscose); the nitrates, in their applications to explosives, on the one hand, and the spinning of artificial fibres (lustra-cellulose), on the other; and the cellulose acetates. ~La Viscose et le Viscoide.~ C. H. BARDY (Bull. Soc. d'Enc. Ind. Nationale, 1900, March). This is a report presented to the Committee of Economic Arts of the above Society, dealing with the industrial progress in products obtained by means of the sulphocarbonate of cellulose (viscose). The following developments are noted: _Engine-sized Papers._--The viscose, by coating the fibres with regenerated cellulose hydrate, adds very much to the tensile strength of papers. Increase of 40-60 p.ct. is attainable by addition of cellulose in this form from 1-4 p.ct. on the weight of the paper. _Viscoid._--Solid aggregates are formed by incorporating viscose with mineral matters, hydrocarbons, &c. Products are cast or moulded into convenient forms, and, after purification and sufficient ageing, are available for various structural uses.