From this date the success of the machine was assured, though the inventor and his colleagues were practically ruined, an experience only too common with the early pioneers of many great and useful industrial enterprises. In fact, the firm of Messrs. Donkin were the only people to profit from the invention, for they manufactured a number of machines, as stated in the report of the Jurors of the Exhibition of 1851, and from 1803 to 1851 no less than 190 Fourdriniers were set to work. CHAPTER II CELLULOSE AND PAPER-MAKING FIBRES When plants such as flax, cotton, straw, hemp, and other varieties of the vegetable kingdom are digested with a solution of caustic soda, washed, and then bleached by means of chloride of lime, a fibrous mass is obtained more or less white in colour. This is the substance known to paper-makers as paper pulp, and the several modifications of it derived from different plants are generally known to chemists as cellulose. Although plants differ greatly in physical structure and general appearance, yet they all contain tissue which under suitable treatment yields a definite proportion of this fibrous substance. The preparation of a small quantity of cellulose from materials like straw, rope, hemp, the stringy bark of garden shrubs, wood, and bamboo can easily be accomplished without special appliances. Soft materials, such as straw and hemp, are cut up into short pieces, hard substances like wood and bamboo are thoroughly hammered out, in order to secure a fine subdivision of the mass. The fibre so prepared is then placed in a small iron saucepan, and covered with a solution made up of ten parts of caustic soda and 100 parts of water. The material is boiled gently for eight or ten hours, the water which is lost through evaporation of steam being replaced by fresh quantities of hot water at regular intervals. When the fibrous mass breaks up readily between the fingers, it is poured into a sieve, or on a piece of muslin stretched over a basin, and washed completely with hot water until clean and free from alkali. Hard pieces and portions which seem incompletely boiled are removed, and the residual fibres separated out. These fibres are placed in a weak, clear solution of ordinary bleaching powder, left for several hours, and subsequently thoroughly washed. This simple process will give a more or less white fibrous material. The purest form of cellulose is cotton. A very slight alkaline treatment, followed by bleaching, is sufficient to remove the non-fibrous constituents of the plant, and a large yield of cellulose is obtained. For this reason the cotton fibre ranks high as an almost ideal material for paper-making, possessing the quality of durability. Cellulose is an organic compound, containing carbon, hydrogen, and oxygen in the following proportions:-- Carbon 44·2 Hydrogen 6·3 Oxygen 49·5 ----- 100·0