Wood.—Two varieties of pulp suitable for paper manufacture may be obtaiued from wood, viz. mechanically and chemically prepared pulps. Almost any kind of wood may be used, those being chosen which most readily yield a pulp by suitable treatment. Hitherto wood-pulp has not been very largely employed by paper-makers in this country, chiefly because there has been a plentiful supply of other material ; but in America and on the Continent, large quantities are consumed every year. What is used here comes principally from Sweden and Norway, and may be obtained either bleached or unbleached. When properly prepared, wood-pulp is a very valu able material, and may be used either alone or mixed with other fibres in papers of good quality. The amount of cellulose differs in various woods, running from 39.47 (oak) to (fir).
Straw.—As a material for mixing with other fibres, straw-pulp is in great demand. For thie purpose, it is valuable ; but if used alone, only very inferior paper can be made from it. Though straw does not yield a very large amount of fibre, yet the supply of it is in most districts pretty considerable and constant. The varieties generally used are oat, wheat, rye, and barley ; of these, rye is considered the most suitable, on account of its yielding the largest amount of fibre ; next iu importance comes wheat. The amount of actual cellulose in straw is comparatively large (say 49.00), but probably not more than 35 per cent. is actually obtained as pulp, the reason being that a large portion of the cellulose is in the state of•loosely aggregated cellular tissue, and that much of this is lost in the treatment.
Jute.—Fibre from jute possesses properties that would render it extremely valuable as a paper-making material, if means could be devised whereby it could be economically bleached to a good white, at the same time preserving the strength of the fibre. Hitherto, this has not been accomplished, hence jute has received only a limited application, having been used chiefly for papers in which a great degree of whiteness is not essential. Jute is usually obtained in the form of " butts" or " cuttings," these being the portions (root-ends, &c.) rejected by the textile manufacturer. (See Fibrous Substances, pp. 940-5 ; Jute Manufactures, pp. 1176-1186).
Bamboo and Canc.—Much attention has been given of late years to the bamboo (see Fibrous Substances, pp. 920-1) as a probable source of paper-making material. It has been made the subject of a series of very carefully-conducted experiments by Thos. Routledge, and is highly recommended by him. Before the subject was taken up by him, many attempts had been made to obtain pulp from the bamboo, but they were economically unsuccessful, as the large amount of silica present rendered it necessary to act upon it with very strong solutions of caustic soda, at high pressure (150-160 lb. a sq. in.). The difficulties of such a treatment are well-nigh insur
mountable. In all these trials, it was the well-developed and matured plant that was used. If, instead of this, the young and succulent shoots are taken, before the plant has had time to develop much woody substance or ailicious covering, the case is materially altered. These shoots are very easily reduced to a suitable paper-making material, by simple digestion in com paratively weak solutions of alkali, at the ordinary atmospheric pressure. Before this treatment, however, Routledge proposes to free the plant from a large quantity of sap and juice by crushing between fluted rollers this considerably facilitates the subsequent boiling operation. Owing to the fact that the young green shoots contain about 75 per cent. of moisture, and that the remainder yields only 60 per cent. of fibre, it would be necessary to partially prepare the fibre at or near the spot where the bamboo is cultivated. The quality of the pulp produced is excellent. The bamboo grows with enormous rapidity, sometimes at the rate of even 1 ft. in a single night, and according to Bondage, if the cutting of the shoots be attended to carefully, the plant will continue year after year to throw out fresh ones. The variety to which attention has hitherto been directed is Bambusa vulgaris; there are, however, other members of the same family which would perhaps be equally suitable. There appears not the slightest doubt, that if Routledge's conclusions are correct, we have here an almost boundless and very valuable source of material. Unfortunately, the opinions of experienced men differ somewhat on the question ; but notwith standing this, the subject is one that deserves very careful attention, as it is becoming obvious that in the future, perhaps the near future, the supply of esparto, to which the paper-makers of this country now look for the largest proportion of their raw material, will be considerably smaller than at present, and may in fact ultimately cease altogether. That it is steadily diminishing, is evident, and this, together with the fact that it takes about 14 years to raise from seed, if indeed it could be conveniently done at all, renders it absolutely necessary that manufacturers should devote more attention to probable new sources of material.