Although experiments in search of suitable substitutes for rags began to be made in the eighteenth century, it was Keller’s invention of ground wood in 1840, Routledge’s work on esparto grass and wood with a soda process in 1854, and our own fellow countryman Tilghmann’s patent of the sulphite process in 1866, from which we may date the beginnings of the now extensive use of materials other than cotton and linen wastes.
The accompanying table, taken from the United States Statistics of Manufacture for 1909, gives an illuminating indication of the rapid growth of our paper industry, and also shows the remarkable increase in the use of wood celluloses.
Note.—Statistics are taken from U.S. Reports for 1909. Subsequent reports are obtainable from the Director of the Census, Washington, D.C.
It may be observed that the percentage of increase in the use of wood-pulp of all kinds for the decade 1899–1909 was 111.6, and of rags, 50. Approximately four and one-quarter millions tons of paper were produced in 1909, for which the fibers used figured in the following proportions:
| Per Cent. | |
| Wood-pulp | 61.6 |
| Old and waste papers | 21.4 |
| Rags | 7.8 |
| Straw | 6.6 |
| Manila (rope) | 2.6 |
Of the total amount of wood fibers, the various proportions were approximately as follows:
| Per Cent. | |
| Ground wood | 47 |
| Sulphite pulp | 42 |
| Soda pulp | 11 |
A further investigation as to the species of woods used shows that, while spruce is still the most important, contributing nearly 60 per cent, other woods are being increasingly used.
Another noteworthy fact is the mighty increase in imports of wood-pulps, which jumped from 33,319 tons in 1899 to 307,122 tons in 1909, an amount equal to 12 per cent of all that is used in the United States.