The acquisition of the raw material represents merely the preliminary phase of the whole issue. To reduce it to pulp involves the consumption of coal—cheap water-power is rare in these islands—and so the probable fuel bill requires to be sounded. How many tons of coal will be required to produce a ton of pulp? It is a simple question and one which prompts another, closely allied thereto, namely, “How many tons of such-and-such material will be required to furnish a ton of paper?”
This is the rock upon which many buoyant expectations have been completely wrecked. Still confining ourselves to the couch grass, and considering the second factor first, we find that it has rather a low yield efficiency, this being in the neighbourhood of 27 per cent. In other words, it will require nearly four tons of crude grass to produce one ton of paper. When ranged beside esparto grass, with which it seems to have much in common, and which therefore is a convenient comparative unit, the outlook for the couch grass is completely shattered, because the efficiency yield of esparto is high, 43·5 per cent. Only a little more than two tons of grass are necessary to produce one ton of paper.
But the fuel factor is far more destructive to the claims of the waste grass growing upon the seashore. To make one ton of paper from esparto grass, under the most favourable conditions, requires 3 tons of coal. In actual practice it ranges from 3·5 to 4 tons. But with spartina grass the coal consumption is forced up to 5, and even to 7, tons under the unfavourable conditions prevailing in many paper-mills. Accordingly, it will be seen that couch grass cannot be construed into an attractive raw material for paper. I may say there are other objections to its use, but the foregoing are sufficient to bring about its rejection in this phase of utility.
Even if we take those materials which are accepted as being the most favourable to the manufacture of paper we gain enlightenment. One ton of waste-paper will not yield one ton of new paper as might be imagined. The loss in re-manufacture is about 25 per cent., so that from the 58,000 tons which enter into the made waste of the country we could produce about 44,000 tons of new paper. Cotton rags have a high yield efficiency, being in the neighbourhood of 85 per cent. and upon this basis we might safely expect a yield of some 16,000 tons of paper from the 19,000 tons of rags committed to the dust-bins of the country.
It may be mentioned that in the search for indigenous materials whence paper might be manufactured, the whole gamut of obvious domestic contributions to the issue have been examined, including such substances as sawdust, wood-shavings, wood-slats, grasses of which there are over 100 varieties, mimosa bark, peat, straw, flax-wastes, flax-shoves, and dried potato vine. Of this wide selection only four materials hold out any promise of extending commercial possibilities. These include sawdust, wood-shavings, wood-slats and straw, with potato haulm serving as an excellent material for the fabrication of a coarse, strong, brown packing paper. Of course, it must be explained that these materials are in addition to those generally utilized in the industry, such as rags, sacking, bagging and reeds, to mention only a few substances.
The definite end sought in the first instance was not so much the discovery of suitable substances to supersede entirely the imported mechanical and chemical pulps, as the presentation of materials which might be considered effectively as useful for dilution purposes. By this is meant the production of a pulp, made perhaps from some familiar product, which, when added to a certain proportion of the conventional pulp, would yield a paper comparable with that derived from the last-named exclusively. Any success recorded in connection with a diluent offers the means to enable a specific quantity of the imported raw material to be induced to go farther than would be the case otherwise, this tendency becoming accentuated as dilution is increased.
It was essentially in this light that the feasibility of pressing sawdust, wood-slats, and other wood and vegetable refuse was considered. Of course, behind all these developments, experiments, and researches, there has been the lingering hope that ways and means might ultimately be found of enabling us to dispense with outside sources of supply in their entirety. This hope still prevails, and, if properly fostered, may lead to realization. But to consummate such an end it is essential to employ materials capable of yielding a pulp as closely resembling the article derived from the tree as possible. Patient investigation proved that sawdust offered the most attractive possibilities in this connection.
While doubt has been expressed concerning the adaptability of sawdust to this duty there are the experiences of Canada and the United States to guide us. Indeed, we need not go out of these islands to obtain confirmatory evidence of its applicability to paper-making. Britain pioneered the utilization of sawdust for the manufacture of paper, and, by a strange coincidence, it was the Napoleonic wars which compelled us to resort to such a manifestation of enterprise. With the exit of Napoleon from the world’s political stage the necessity to exploit sawdust in this connection disappeared, and so the process fell into disuse, to lie dormant for a round one hundred years. Consequently the use of sawdust really represents but a revival of an old practice.
But, so far as these islands are concerned, and under normal conditions, sawdust can scarcely be regarded as a paper-making material. The quantity available from our sawmills is too meagre to enable the idea to be practised extensively. There is just one chance of placing the development upon a firm footing. We are big consumers of timber, but the greater part of our requirements in this field are satisfied by importing supplies in a manufactured condition. Attempts are being made to restore the British wood-working industry by importing lumber in the slabbed condition, that is square trimmed logs either in the form of huge rafts or demountable ships. Should this development mature then our sawmills will become clogged with huge accumulations of wood-waste in the form of the sawdust, the exploitation of which will be keenly appreciated.
During the war, however, the necessity to exploit the forests of Britain to contribute to the requirements of the army and mines in regard to wood has resulted in the piling-up of huge heaps of sawdust. It was discovered that in Scotland alone this residue was accumulating at the rate of 60,000 tons a year, through the activity of the Canadian lumberjacks. Conservative estimates place the annual sawdust yield throughout the British Isles at 150,000 tons. Of this gigantic contribution only from 5 to 10 per cent. is drawn from hard woods. The balance, 90 to 95 per cent., is derived from the soft woods and so furnishes a huge reservoir of potential raw material for paper-making.