Classification, of papers.
With regard to the uses to which they are put, papers are divided into several classes : (1) Writing paper, embracing what are known as bond, ledger, record, linen, bank note, ordinary writing and envelope papers. These are thoroughly sized papers, the best of which are made from rags, hemp and ramie fiber, while the poorer grades con tain also a varying amount of wood pulp.
(2) Printing paper, embracing book paper and newspaper. The best grades of the former are made from rags, while the poorer grades contain esparto, straw and wood pulp. Newspaper is al most universally made from ground wood pulp which has not been sub jected to any chemical treatment, with a small percentage of sulfite pulp. Some newspapers also contain straw.
(3) Wrapping papers, embracing also paper bags and heavy envelopes. The best grades of these are made from jute, sisal and common rags ; the poorer grades may be made in part or entirely from chemical wood pulp, straw, or ground wood. A particularly strong paper, known as "kraf brown," standing between manila and jute papers and wrap ping paper made from regular chemical wood pulp, is now made by under-cooking wood by the sulfate process and subsequently. .grinding the fiber in a special mill.
(4) Blotting and tissue paper. The best grades of the former are loosely made and free from load ing ; poorer grades contain chemical wood pulp and large quantities of clay. They are not sized. Tis sue papers are very thin and should be made from strong fiber, such as hemp and cotton.
(5) Cardboard and pasteboard are usually made of low-grade materials. Strawboard is manufac tured from unbleached and imperfectly washed straw. Parchment paper is made of long-fibered material by dipping the finished sheet in sulfuric acid, washing with water, then with ammonia, and finally with water.
Extent of the paper industry.
The quantity, kind, and value of the raw ma terials and the paper made therefrom in the United Paper-making materials of the future.
Inspection of the above table shows that by far the largest quantity of paper, more than half in fact, is made from wood. This enormous demand for 3,000,000 cords per year, when added to the quantities otherwise used, is rapidly decreasing the visible supply of the better-known paper-making woods, the effect of which is already being felt in some localities. Greater difficulty in securing and
increasing cost of spruce and poplar suitable for paper-making may be expected. It is highly prob able, however, that modern agriculture will be able to meet the demand for suitable substitutes for spruce and poplar ; indeed, there is every reason to think that very many other woods are also suitable for paper-making, and with decreasing supplies of the better-known kinds, these will be used more and more. Such use has already begun, as is shown by the very large consumption of hemlock, pine, balsam and cottonwood, and by the fact that yel low pine and chestnut are now being developed as paper-making materials in the South. The high yield of paper obtained from wood, together with the ease with which it is prepared for treatment, its freedom from dirt, the large quantity that can be got into the digester for treatment, have con tributed to make wood the cheapest paper-making material. For all but the most exacting purposes, it makes a suitable paper at a minimum cost. Any successfully competing material, therefore, must compare favorably with wood in the final cost of the finished paper and in the quality of the paper, its freedom from dirt, its appearance, strength, durability, and resistance to wear. At present, the price of pulp wood averages about six dollars per cord, and one cord makes approximately 1,300 pounds of good, clean, white paper. Six dollars' worth of any substitute, therefore, must make 1,800 pounds of an equally good paper. A number of fac tors help to make the cost of paper from other material greater than from wood. Cereal straws, wild grasses, corn-stalks, bagasse and cotton-stalks must be carefully freed from the dirt which they contain, while the high percentage of silica which the straws and wild grasses contain helps to make their chemical treatment somewhat more costly than that of wood. It is doubtful, therefore, whether these materials can yet be delivered at the mills and treated as cheaply as can wood.