Mr. Dickinson afterwards obtained a patent, in 1855, for making a union paper, consisting of a thin sheet of that made by his own machine, and a similar sheet made by a Fourdrinier machine united together. For this purpose the two sheets were brought together, as they passed from the machines, whilst still wet and in an unfinished state, and were pressed together between rollers, by which means they were completely incorporated. The object of this contrivance was to combine, in a single sheet, the different kinds of surface which paper made by those two modes of manufacture present. It is also employed economically for engravings, to give a fine surface to a thick sheet of coarser material. The threads in postage envelopes and in bankers' cheques, are introduced by this process of plating two surfaces together.
The greatly increased consumption of paper threatened to exhaust the supply of the raw material, notwithstanding the large import from abroad and the enormous supply derived from the waste of the cotton mills, which, when mixed with rags, produces good paper. The quantity of old rags, old junk, and other fibrous materials imported for the purpose of making paper, in 1850, is stated in the Jury Reports of the Great Exhibition to have amounted to 8,124 tons. This large importation, added to the stock of rags supplied by the country itself, was, however, inadequate to meet the consumption, and search was anxiously made for other fibrous substances that could be converted into paper;—peat, cocoa-nut fibre, grass, straw, and even wood have been used for the purpose. Of those substances, straw has been most successfully applied, and straw paper—excellent to write upon, though not bright in colour—is now made at very low prices. The straw is first cut up into short lengths, of about half an inch, by a chaff-cutting machine, and after undergoing various processes of trituration and bleaching, it is reduced into a pulp, sufficiently adhesive to make a strong paper.
The plan of drying the paper as it leaves the rollers of the machine, was introduced by Mr. Crompton in 1820, and that gentleman was also the first to introduce a machine for cutting the paper into sheets as soon as it is dried. The first invention of the kind was patented by Mr. Crompton, in conjunction with Mr. Miller and Professor Cowper, in 1828. The continuous web of paper was made to pass directly from the drying apparatus to the cutting machine, by which it was first slit into bands of the required width by means of a series of sharp discs of steel, adjustable on two parallel axes. The bands of paper then passed on to shears, placed transversely, that cut it into sheets of any required length, which were laid upon one another, to be divided into quires.
Several other cutting machines have since been invented, the simplest of which is the one patented by Mr. Dickinson, which is represented in the woodcut.
The paper may be taken directly from the drying cylinders or from a reel, as shown in the diagram at a. The sheet passes over a large drum and through several guide rollers, till it is carried across the table a h, where it is cut lengthwise by knives, as it passes along. A series of chisel-edged cutters are placed at regulated distances beneath the table; and whilst the paper is stretched over it, several circular knives, f f, fixed into a swing frame, g g, at corresponding distances with the knives beneath, are swung across the sheet, and cut it in the manner of a pair of shears. Other kinds of cutting machines are contrived, by which sheets of writing paper, when collected in quires, are squeezed tightly together, and their edges are smoothly and evenly cut.
We must not conclude this notice of Paper Making Machinery without alluding to the ingenious self-acting mechanisms for making envelopes. In the Great Exhibition of 1851 there were three different machines exhibited in action, each one producing, with great rapidity, those neat coverings for letters, for which the penny postage system has created so great a demand. The paper, cut into the desired form by a separate machine, was piled up on one side of the envelope folder. It was taken, sheet by sheet, and stretched on a small table, on the middle of which there was a trap door, held up by a spring to a level with the rest of the table. A plunger, of the same size as the envelope to be made, pressed the trap down into a recess, and raised the four corners of the paper, the edges of which were then gummed, and small mechanical fingers folded them down. The completed envelope was then thrown out into a basket, or it slided out of the machine on to those before made.
Each of those machines, with a boy as an attendant, will fold 2,700 envelopes in an hour, which is nearly the same number that an experienced workman can fold in a day with a folding stick. Notwithstanding the supplanting of manual labour to so great an extent by these ingenious mechanisms, the effect of increased facility of manufacture has been to give increased employment, and many more persons are now engaged in making envelopes than were so employed before the invention of the machines.