Cheap literature and the large development of newspapers are
principally attributable to the improvements in Paper Making, by the
aid of machinery.
In the former modes of making paper, the workman held in his hands a
square frame covered with wires, which he dipped into the prepared
cotton or linen pulp, which was kept in suspension by being agitated in
water, and taking up a quantity sufficient to cover the frame, he moved
the pulp about horizontally, to spread it evenly over the surface of
the wires. Another workman transferred the layer of pulp on to felt,
and in this manner one sheet was laid upon another, with felt between
each. They were next subjected to great pressure, for the purpose of
making the fibrous particles cohere sufficiently to form sheets of
paper. The felts were then removed, and the sheets were piled upon one
another and again pressed, after which they were dried, sized, and
finished.
Paper Making, by that process, was a slow operation. The thickness
and evenness of the sheets depended altogether on the judgment and
skill of the workman, and their size was necessarily limited by the
dimensions of the frame. By the improved methods, nearly all the work
is done by machinery. The soft fibrous pulp, which is to be converted
into paper, enters the machine at one end, and in the course of two
minutes it is delivered at the other end of the machine in a continuous
sheet, that may extend for miles. By supplemental contrivances the
paper is cut into sheets, piled together, and presented in a salable
form.
The world is indebted to a Frenchman, named Louis Robert, for the
invention of the first machine for making paper. He was a workman in
M. Didot's paper mill, at Essones, and for his contrivance of a method
for making continuous paper, he obtained from the French Government, in
1799, the sum of 8,000 francs and a patent for the manufacture of the
machines. The political agitation in France at that period prevented
much progress from being made with the invention, but after the Peace
of Amiens, in 1802, M. Didot, jun. came to this country, accompanied by
his brother-in-law, Mr. Gamble, for the purpose of making arrangements
to carry it into effect. They induced Messrs. H. and S. Fourdrinier to
engage with them in bringing the machinery to perfection, and patents
obtained in this country by Mr. Gamble were assigned to them in 1804.
The engineering establishment of Mr. Hall, at Dartford, in Kent, was
selected as best adapted for the purpose of making the machinery and
for carrying the plans into operation. Mr. Bryan Donkin, who was
engaged in the manufactory, principally assisted in bringing the
machinery to perfection. The difficulties attending the completion of
all the parts, to get them to work effectually, and the obstruction
encountered in introducing the machine-made paper, rendered the
enterprise a ruinous speculation to those who first engaged in it.
Messrs. Fourdrinier having expended £60,000 in perfecting the machine.
[Illustration]
The apparatus, of which a representation is given in the annexed
woodcut, was very complicated, but the essential parts may be readily
understood.
The rags from which the paper is made undergo a variety of processes
before they are properly reduced into a state of pulp. They are sorted,
dusted, boiled, and torn into pieces by passing through cutting
rollers; they are then bleached and again submitted to the grinding
action of rollers, which reduce them into a state of fine pulp,
resembling milk in appearance. The pulp thus prepared is placed in a
large vat, where it is kept constantly agitated, to prevent the more
solid parts from being deposited. From the vat the pulp is discharged
into a cistern, over the edge of which it flows in a continuous stream
upon an endless wire cloth, the meshes of which are so fine that there
are as many as 6,000 holes in a square inch.
The wire gauze, on to which the pulp is poured, is about 4 feet wide,
and 25 feet long, and it is kept constantly moving onwards, by rollers
at each end, over which it passes. The gauze is stretched out perfectly
level, and the pulp is prevented from flowing over the edges by straps
on each side, which limit the width of the paper. As the endless
wire cloth moves along, an agitating motion is given to it, by which
means the pulp is spread evenly over the surface; the water is also
drained off through the interstices of the gauze, and this part of the
process is expedited in the improved machines by producing a partial
vacuum underneath. Before the sheet of pulp has arrived at the farther
extremity of the wire cloth, it passes between two cylinders, the under
one of which is of metal, covered with felt, and the upper one of wood.
A slight pressure given to the pulp in passing between those cylinders
imparts sufficient tenacity to it to enable it to be transferred from
the wire gauze on to an endless web of felt, by means of a slice that
clears the pulp from the wire gauze, and deposits it on the felt. The
latter is kept moving at exactly the same speed as the wire gauze,
otherwise there would be either a rent or a fold on the sheet. The
paper, still in a very wet state, is carried between cast iron rollers,
and its fibres are forcibly pressed together, which operation squeezes
out the water, and so far gives tenacity to the pulp that it may be
handled without tearing. The sheet then passes on to other rollers, by
which it is further compressed, and its surface smoothened. The paper
is, however, still damp, and requires to be dried. This is done by
passing it over large metal cylinders, heated by steam. The process of
making the paper is then completed, and the continuous sheet may be
wound upon a reel to any length; but it is now usual to cut it up into
sheets as soon as it leaves the drying cylinders.
The wire cloth moves at the rate of from 25 to 40 feet per minute, and
such a machine would consequently make at least 10 yards of paper in
that time, which is equal to a mile in three hours. The width of the
paper is usually about 4½ feet, therefore each machine will make 10,450
square yards of paper in twelve hours; and there are upwards of three
hundred of such machines at work in this country. The value of the
paper thus produced is calculated to exceed two millions sterling.
Numerous improvements have been made in Fourdrinier's original machine,
but the principle of its construction remains essentially the same,
and it is by this means that most of the paper now used for writing
or printing is manufactured. A paper-making machine, on a different
principle, has, however, been invented by Mr. Dickinson, and has been
carried by him to great perfection. Instead of allowing the pulp to
fall on to a flat surface of wire gauze, a polished hollow brass
cylinder, perforated with holes and covered with wire cloth, revolves
in contact with the prepared pulp, and a partial vacuum being produced
within the cylinder, the pulp adheres to the gauze, and its fibres
cohere sufficiently, before the cylinder has completed a revolution, to
be turned off on to another cylinder covered with felt, on which it is
subjected to pressure by rollers, and is thence delivered to the drying
cylinders.
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.
[Illustration]
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.