These frames are generally made so as to hold each one sheet, and each sheet when sufficiently coherent is hung or fixed against a wall to dry. It is then rubbed over with thin paste made of rice-flour and water, again dried, and afterwards pressed. The process is usually completed by glazing, which is done in some cases by rubbing each sheet with an oiled stone roller.
In Europe, down to the beginning of the 18th century, cotton, flax, and hemp were the usual materials, except rags, used in the manufacture of paper. Cotton and linen rags are now chiefly used for this purpose, because they are more easily and cheaply converted into pulp, and furnish a better article when finished than other fibrous materials. But the comparatively high price of rags, and the enormous demand for cheap paper, have compelled manufacturers to turn their attention to other sources of supply, and efforts are being unceasingly made to manufacture paper from the fibres of different vegetable substances.
It is objected by manufacturers of paper that pulp from unwoven fibres does not draw through the present machinery so well as that made from rags. A modification of machinery would no doubt remedy this. But new materials involve new machinery for reducing them to pulp, and the older paper - makers have not yet established machinery suited for these new materials in addi tion to that at present in use. Enterprising men are laying themselves out to make pulp or half-stuff for sale to the paper-makers, and it will be by those men that any new materials will be worked. Many thousands of inventors and manufacturers, many years of incessant labour, and millions of pounds sterling have been expended in experiments upon wood, straw, and similar substances ; but the problem of obtaining good paper, at a moderate cost, from raw vegetable fibre, is yet only partially I solved. Neither straw, nor wood, nor any similar material has superseded linen and cotton rags. The raw fibre of papyrus was used for thirteen centuries ; the reign of rags has lasted twelve and a half centuries. The most practical of the sub stitutes seems to be straw, the first useful paper from which was made in 1800, and used in a book printed by Burton of London, a copy of which was presented by the Marquis of Salisbury to king George Iii. The work is entitled An His
torical Account of Substances used in Paper making. Cobbett, in 1828, employed, experi mentally, some paper made from the husks of Indian corn, but with little success. The substi tution of straw in 1800 was regarded of great national importance, and highly deserving support. It was neglected for many years, but straw is now extensively used in paper-making in England, and on the Continent of Europe.
A book written in German by M. Schaffers so long ago as 1772 (Sammtliche Papierversuche von Jacob Christian Schaffers, Prediger zu Regensburg, Regensburg 1772), contains sixty specimens of paper made from the bark of the willow, beech, aspeirillawthorn, lime, and mulberry ; from the down of the asclepias, the catkins of black poplar, and the tendrils of the vine ; from the stalks of nettle, mugwort, dyer's weed, thistle, bryony, burdock, clematis, willow herb, and lily ; from cabbage-stalks, fir-cones, moss, potatoes, wood shavings, and sawdust ; and it has been likewise made froqa rice, hop- bine, liquorice -root, the stalks of the mallow, and the- husks of Indian corn. M. Bardoux, a manufacturer of Poictiers, manufactured paper from oak, walnut, pine, and Chesnut. The question of the present day there fore is not, of what vegetable subtances can paper be made?' but 'which of them can compete with rags?' In a memorandum, drawn up by Dr. J. Forbes Boyle, on the materials for paper-making pro curable from India, he reviewed the entire unutilised and utilised fibrous plants of 'India. Several bales of the straw of certain Indian grasses were forwarded to the Society of Arts, but the report of competent judges was that none of them are well adapted for the making of paper, though they did not doubt that paper can be made from all of them. The common rice-straw (Oryza sativa) was the best. They added that all the samples are very inferior in paper-making quality to many substances which can be obtained readily in England, but which are not even con sidered as worth using.