With the compliments of the
Geo. W. Wheelwright Paper Co.,
Boston, Mass.

FROM
PAPER-MILL TO
PRESSROOM

ANCIENT PAPER-MAKING

The tools of the primitive paper-maker consisted of a pulp vat for the fiber-laden water, a frame, or mold across which was stretched a mesh of closely-spaced wires, and a removable frame known as the deckle; hence the term “deckle edged.” The beating was done by iron shod hammers which were raised and released by cams on a shaft turned by water power: this machine called a stamper is shown in the foreground of this picture.

FROM
PAPER-MILL TO
PRESSROOM

By
WILLIAM BOND WHEELWRIGHT
Author of “How Paper is Made,” etc.

The Collegiate Press
GEORGE BANTA PUBLISHING COMPANY
MENASHA, WISCONSIN
1920

Copyrighted 1920
by
William Bond Wheelwright

PRINTED AND BOUND BY
GEORGE BANTA PUBLISHING CO.
MANUFACTURING PUBLISHERS
MENASHA, WISCONSIN

TO MY FATHER
George William Wheelwright
AND TO THE MEMORY OF HIS FATHER
WHO ENTERED THE PAPER BUSINESS IN 1834
THESE PAGES ARE
RESPECTFULLY INSCRIBED

TABLE OF CONTENTS

NOTE—This book is printed on Wheelwright’s “B.P.F.” paper 25x38-70.

LIST OF ILLUSTRATIONS

INTRODUCTION

In the following pages I have endeavored to present a treatise on paper free from confusing technicalities, yet sufficiently intimate to be of service alike to the manufacturer, the salesman, and the consumer of paper viewing the subject in a broad way from the paper mill to the pressroom. The manufacturer and the consumer may notice the omission of some details, as I have aimed to touch mainly on such points as are essential to a good understanding of the work-a-day problems of paper after it reaches the printer.

I am convinced that in many cases the problems of the pressroom are too slightly understood by the “paperman,” while the technicalities of paper-making are only too vaguely comprehended by the printer. I also feel that both should have at least an acquaintance with the history and progress of paper-making.

William Bond Wheelwright.

Appleton, Wisconsin,
January, 1920.

CHAPTER ONE
THE TRADITION AND HISTORY OF PAPER-MAKING

It would be difficult to single out among the diversified objects of human investigation,” wrote John Murray in his remarks on “Modern Paper” (published in 1829), “a question more curious or interesting than the medium which bears the symbols that register the circumstances and events of past ages.... It is through such wonderful media that we are introduced into the multitudinous throng of a world’s tenantry, and from their inscription learn what they thought, and said and did.... In deciphering these transcriptions of ideas and memorials of humanity we virtually converse with minds long since numbered with those who people the world of spirits; and even the mummy from his cerements in his sycamore coffin, recovered from the vaults of eternal pyramids, talks with us by virtue of the roll of papyrus which he holds in his hand.”

From this substance of Egyptian origin is derived the name of its modern successor—paper. Paper, which in convenience and varied utility is as much in advance of its forerunner as papyrus was in advance of brick, stone, lead, copper, brass, leaves, bark, wood and skins, the successive media for the transcription of human thought.

The exact date of the origin of paper-making has probably yet to be discovered, though the researches of Dr. Aurel Stein and others have traced its antiquity back into the second century, B. C. (see Encyclopædia Britannica).

According to R. W. Sindall (“The Manufacture of Paper,” 1908), the earliest reference to the manufacture of paper is to be found in the Chinese Encyclopædia, wherein it is stated that Ts’ai-Lun, a native of Kuei-yang, entered the service of the Emperor Ho-Ti in A. D. 75, and, devoting his leisure hours to study, suggested the use of silk and ink as a substitute for the bamboo tablet and stylus. Subsequently he succeeded in making paper from bark, tow, old linen and fish-nets (A. D. 105).

The art thus originated and nurtured by the Chinese remained to be transmitted to Europe by the Arabs after their conquest of Samarkand in A. D. 751.

The first centers of the industry founded in the eleventh century were in Spain, at Toledo, Valencia and Xativa. From Spain the craftsmen migrated to Sicily, Italy, France and the Netherlands.

A mill was established at Hainault, France, as early as 1190.

The oldest-known document on cotton paper is a deed of King Roger of Sicily, dated 1102. It is probable that the famous mills of Fabriano sprang from Sicilian sources; their establishment was followed in 1360 by a mill in Padua, and later in Treviso, Bologna, Palma, Milan and Venice, while the first paper-mill of Germany was that of Ulman Stromer at Mainz in 1320.

A most interesting account of this period of paper-making is given as follows by Harold Bayley in his volume, “A New Light on the Renaissance:”

“In the Dark Ages there existed in the south of France a premature civilization far in advance of that of the rest of Europe. Among the arts and industries that flourished in Provençe and the surrounding districts, paper-making was one of the foremost. Not only was this district the cradle of European paper-making, but for many centuries it remained the center of this industry.

“The freedom and prosperity of Provençe attracted large numbers of persecuted Jews and heretics, who took refuge there, and by their industry and intellect augmented the power and influence of the country. So deeply, indeed, did heresy enter into the politics of Provençe, that in 1209 the Church of Rome considered it necessary to launch a crusade against the infected district.

“During a period of twenty years the heretical inhabitants were either extirpated or driven into perpetual exile. Those who escaped carried with them a passionate affection for their destroyed fatherland, and an undying hatred against the tyranny of the Church of Rome.

“It will be shown that from the appearance of the first water-mark in 1282 these mysterious marks are, speaking broadly, the traditional emblems of Provençe.

“From the fact that fundamentally the same designs were employed all over Europe, we can deduce the inference that Provençal refugees carried their art throughout Europe, just in the same way as at a later period and under somewhat similar circumstances Huguenots carried new industries into strange countries. It will also be shown that the same code which unlocks many of the obscurities of paper-marks elucidates the problems of printers’ marks, and evidence will be brought forward that paper-makers and printers were originally in close touch with each other, held similar views, and were associated in identical aims.”

Gradually the secrets of the craft pursued their northward trail into the Netherlands. Saardam, in the Duchy of Holland, became in the eighteenth century an important center, employing, it is said, one thousand persons.

In England, which for many years imported all its paper, the first mill was erected about 1498, as is attested by an entry for that year in the privy-purse expenses of King Henry VII. Further corroboration is also to be found in the following quaint verse from Wynken de Worde’s edition of “De Proprietatibus Rerum”:

And John Tate the younger Joye mote he broke,
Which late hathe in England doo make this paper thynne
That now in our Englyshe this book is written inne.

England, however, achieved no reputation for fine papers until the establishment of the famous James Whatman, in 1760.

In the meantime, the trade had taken root in our own country when, in 1690, William Rittenhouse started the first American mill on the Wissahickon river at Roxborough, near Philadelphia, and thirty years later New England’s first mill was established by David Hinchman at Milton, Massachusetts.

The migratory characteristics of the trade were made possible by the simplicity of the machinery which was required in these times. Pictures of early mills depict a mortar and pestle in which to macerate the rags to pulp, a small vat for the paper stuff, a mold on which the paper was formed, and a screw press with which to squeeze out the water from the new-formed sheets.

Mechanical improvements came with painful slowness, and no doubt each small advance was a jealously guarded secret.

The mortar and pestle were succeeded by a machine mechanically imitating the handwork of beating the rags to pulp. This was called a stamper. The old mortar remained, but the beating was done by iron-shod hammers, which were raised and released by cams on a shaft turned by water-power. Note the stamper in the foreground of the picture of Ancient Paper-making on page [II].

The Dutch improved upon this device by the invention of the Holland beating engine about 1770, which in its essentials is practically the same thing to-day on a much larger scale.

Until the year 1798 there had been no further advance in mechanical inventions for paper-making, but let us pause a moment for a consideration of the paper itself.

The early raw material consisted solely of cotton and linen rags, and there was very little variety of output. Until 1750 all the paper was made on molds, the seats of which were made by fine parallel wires supported by heavier wires, which ran at right angles to them. Consequently all the paper was what is called “laid.” In 1750, at the instance of the famous Printer Baskerville, a mold was made with a woven-wire seat, and the first “wove” paper was used in his famous Edition of Virgil.

The characteristics of the earlier paper are well summed up by Mr. De Vinne in an article on woodcut printing which appeared in Volume XIX, No. 6, of Scribner’s Magazine, a reading of which impresses one with the limitations of ancient paper-making as contrasted with the complexity of modern paper-making, and all the study which its variations impose upon the modern printer who seeks proficiency.

“Much of the paper made in the sixteenth century,” he says, “was unsuitable for woodcuts. By far the larger portion was made of linen stock, hard and rough as to surface, laid, or showing the marks of the wires upon which the pulp had been crushed, or ragged edges, unsized and very sensitive to dampness, uneven in thickness, usually thin in the center and thick at the edges....

“The paper selected was, in most cases, too rough and hard to be forcibly impressed against the delicate lines of fine woodcuts. It was the usage everywhere to soften the paper by a careful dampening.

“When the paper was sized it was more weakened by this dampening, which really lightened the labor of the pressman. But unsized paper was only about half the price of sized, and the inducement to use it was great. The unsized paper was dampened with difficulty, it greedily sucked up water, and when fully wet became flabby and unmanageable. Under searching pressure of the woolen blanket which was always put between the paper to be printed and the printing surface, this flabby paper was forced around the finer lines of the cut, making them much thicker than was intended.”

Let those whose shallowness leads them to regard modern paper-making as an abortion of a once noble art take thought!

The transition from the old ways of paper-making to modern processes was sudden. The century which gave them to us stands out in radiance against the dark ages of heavy toil at the vat and press.

First came the mechanic whose genius caused tons to be produced in the time that pounds were made of yore. Next came the chemist who developed unthought-of raw materials to supply the ever-growing demands of “papivorous” civilization, until it has been said with so much truth that ours is the paper age.

In 1798 an obscure French workman, Louis Robert, of Essonne, announced that he “had discovered a way to make, with one man, and without fire, by means of machines, sheets of paper of a very large size, even twelve feet wide and fifty feet long.”

Times were hard on the continent, yet the Government of France, recognizing the importance of the invention, awarded Robert eight thousand francs and a patent for fifteen years. Furthermore, permission was given to carry over the small working model to England, with the hope of interesting British capital.

A successful attempt to make paper on Robert’s machine having been made in the mill of François Didot, in France, Leger Didot purchased the patent and, accompanied by an Englishman of the appropriate name of John Gamble, proceeded to England and employed Mr. Bryan Donkin to construct a machine.

Being in need of funds, they interested two wealthy London stationers, Messrs. Henry and Sealy Fourdrinier, in their proposition, and in 1804 the first successful machine was started at Frogmore. Much credit is due Mr. Donkin, by whose ingenuity the mechanical difficulties were mastered, but the Fourdriniers, for whom the machine was named, are no less entitled to the honor, as their persistent faith in the machine finally led them into bankruptcy.

After having expended sixty thousand pounds and being reduced to penury, they finally petitioned Parliament for compensation for their losses. Their labors were fortunately appreciated, and a sum of seven thousand pounds was voted them.

Surely all these early pioneers deserve a place in the hall of fame beside that of Gutenberg.

In 1812 the type of machine known as “cylinder” was invented by John Dickinson, whose name is still associated with paper-making, and so different is the machine in principle that Dickinson’s name should also be placed alongside of Robert’s as a benefactor to mankind. Neither of these machines had any means for drying paper, consequently their production was decidedly limited. This lack was supplied by the invention of driers by T. B. Crompton in 1821, who later took out a patent for slitter-knives. Suction boxes were contributed by the ingenuity of M. Canson, a Frenchman, in 1826. John Wilks, an Englishman, produced the first dandy roll in 1830, while Thomas Barratt conceived the idea of making water-marks by means of this roll.

And so, one after another, various useful additions came into existence, until we have the modern paper-machine, which differs mainly in width, length and productive power from the machines of the thirties.

In the meantime, researches for new paper-making materials had been in progress. As early as 1719, Reamur, observing how wasps made their nests from wood, threw out the hint to paper-makers, but for over a century there was no important result.

In 1727, Dr. Brueckmann, a German naturalist, published a work on stones, four copies of which are said to have been printed on paper made with asbestos.

In 1751 M. Guettard in France published his experiments and showed samples of paper made from bark, leaves and wood; while in 1765 Jacob Christian Schaffers, of Ratisbon, published a volume, a copy of which exists in the Smithsonian Library, upon the different sorts of paper he could make without rags.[A]

[A] A copy of the second edition of this work is in the Library of the University of Michigan at Ann Arbor.

Matthias Koops in 1801 printed some account of his patents for utilizing waste papers, straw and wood. This volume, printed on straw paper, with one signature on paper claimed to be made of wood, is well worth reading, and is to be found both in the Boston Public Library and in the Harvard College Library, and quite likely elsewhere.

These experiments are only interesting as forerunners. In their own time they came to naught. Not until 1840 was ground wood-pulp invented by Keller.

The production of cellulose from straw and esparto by the soda process was discovered by Routledge, an Englishman, in 1860, while the first patents for making wood soda pulp were those of Watt and Burgess in 1854.

To an American belongs the credit for the important invention of the sulphite process, Benjamin C. Tilghmann, of Manayunk, Pennsylvania, having taken out the first patents in 1866.

Although excellent fiber was obtained, the engineering difficulties proved so serious that experiments were temporarily abandoned in the United States. But the process was afterward put upon a successful commercial basis by Fry and Ekman, at Berzwik, Sweden, in 1870. Americans soon took up the problem with renewed energy, and the late Charles S. Wheelwright, of Providence, Rhode Island, after a visit to Sweden in 1882 on which he obtained the rights to the Ekman patents, introduced the process at the plant of the Richmond Paper Company, in Providence, and while a commercial success was not realized, it was an important step in the development of the industry, and not many years passed before the United States gained a leading position in the production of wood-pulps.[B]

[B] See Little & Griffin, “The Chemistry of Paper-making.”

Thus in less than ninety years, from Robert’s invention of 1798 to the early eighties, the world witnessed a complete revolution of the paper industry, which had struggled along in the same old rut for some two thousand years.

To-day the United States leads the world in the production of paper. According to the census of 1909, we produced 4,216,708 tons, valued at $232,741,049, an amount which exceeds in tonnage the combined production of England, Germany, France, Austria and Italy.

Well may we be proud of this great industry, which after all is largely the reflection of a nation’s intelligence and culture, and commercial activity.

CHAPTER TWO
RAW MATERIALS

Paper has been defined as “an aqueous deposit of cellulose,” and while this is incomplete as a catalogue of the materials composing a sheet of modern paper, it is an excellent epitome of the foundation of paper-making. Minute cellulose fibers, derivatives of various raw materials, are deposited upon a wire cloth by the passage of a volume of water in which they have been suspended. The pulpy film thus formed becomes a sheet of paper, after the expulsion and evaporation of the water which served as a medium for their deposit.

The minute fibers composing this hypothetical sheet of paper may have been isolated from one of several sources of raw materials in present commercial use, or the sheet may be composed of a mixture of different fibers, all more or less pure cellulose, in accordance with the preliminary treatment each has undergone.

The principal sources from which American paper fibers are derived are cotton and linen rags, hemp, jute, wood, straw; and waste papers.

Previous to the year 1840, the sources were limited to rags. These are almost wholly composed of pure cellulose fibers, which give up their non-cellulose concomitants with slight resistance. The more severe chemical treatments necessary for the isolation of cellulose fibers, from wood, for example, half of which is non-cellulose in structure, were unknown to early paper-makers, and only became possible after the discovery of bleaching-powder by Tennant, and the manufacture of soda by Le Blanc.

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:

Of the total amount of wood fibers, the various proportions were approximately as follows:

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.

Table from United States Statistics of Manufacture for 1909, Showing Rapid Growth of Paper Industry.

The comparative statement follows:

[1] Balsam.

[2] Included in “All other.”

[3] Included with other wood by species.

The high point of importation of chemical wood-pulp was reached in 1914, when approximately 3,600,000 tons came in from Europe and 92,000 from Canada. In January 1916 owing to the war, imports for the month from Europe dropped from an average of 30,694 tons to 12,985 tons, while Canadian pulp increased from an average of 7,654 to an actual importation for the month of 28,833 tons.

Although the use of wood now so heavily overshadows that of rags that it almost seems as though the latter were being slowly abandoned, this is of course only relatively true, their consumption being actually greater than ever. The mere cost of the rags in 1909 was slightly in excess of the total value of all paper products recorded in the United States Census for 1850, a circumstance which leads us to wonder at the timely discoveries which made wood cellulose available.

It is evident, however, that to some extent paper history is already beginning to repeat itself. The visible supplies of wood are markedly less, as evidenced by their increasing costs, and we are forced to a much more active attitude than one of mere speculation as to what new sources may become available to supply our demand for paper, which has lately been increasing in the value of the annual products by almost 11 per cent.

In the decade from 1899 to 1909 shown by government statistics, book-paper advanced 104 per cent in quantity, but 120 per cent in value; writing-paper, 88 per cent in quantity, but 104 per cent in value; wrapping-paper, 43 per cent in quantity and 72 per cent in value. It is true that rising wages account in part for these changes in value, but above and behind all this stands the inexorable law of supply and demand.

The discrepancies between the percentages of increase in production and value serve to emphasize the increasing difficulties in obtaining raw material. That sprucewood is being consumed in this country faster than it is grown, is indicated by the recourse to less-favored species, as well as by the steadily increasing imports, both of pulpwood and wood-pulp. This situation emphasises the great importance of conserving waste papers, in spite of the fact that 21.4 per cent of the fiber used in 1909 in the United States were derived from waste papers. Vast quantities may readily be saved which now go to waste, as was definitely proved by England’s experience during the war, when the imports of pulp were shut off and immediate substitutes had to be found.

This is a matter demanding the attention not only of printers, but of municipalities and nations. It offers an immediate source of relief from the drain on our forests and is hence a most practical form of conservation. Furthermore as demonstrated by the city of Cleveland the revenue from collecting waste papers assists substantially in offsetting the cost of the collection of municipal wastes.

CHAPTER THREE
FUTURE FIBER POSSIBILITIES

The United States Department of Agriculture, in August, 1911, issued a treatise on “Crop Plants for Paper-Making,” in which the author, Charles J. Brand, concluded: “There is some skepticism as to the failure of pulpwood supplies, but this is certainly poorly grounded.

“During 1909 the quantity of spruce used was less by 40,000 cords than in 1907, but the cost was $2,000,000 greater. Present efforts in connection with reforestation of spruce and poplar are not extensive enough to produce any noteworthy effect upon the available supply within a generation.

“At the present rate of increase in consumption, it will require between 15,000,000 and 20,000,000 cords of wood for pulp and paper fiber in 1950. It will certainly be impossible to furnish this from the forests. If every acre cut over each year were reforested, it would be twenty-five or thirty years, or possibly even longer, before the trees could obtain sufficient size to warrant cutting. The forests can not recover from overdrafts continually being made on them. Hence it is only a question of a limited number of years until paper fiber must be grown as a crop, as are practically all other plants materials entering into the economy of man. While the conservation of only a few of the by-products of the farms yielding paper fiber can be accomplished profitably in the near future, and only a few of the plants promise to be money-makers immediately if grown solely for paper production, it seems very probable that raw products, now scarcely considered, may in a few years play an important part in the paper and pulp industry.”

Two lines of research are now being followed by the United States Government. The Forest Products Laboratory of the Forest Service is investigating a large number of coniferous and broad-leaved trees, which have not hitherto been used in paper-making. These sources are likely to be the first which manufactures will turn to, as the processes involved are such as they are already familiar with, and the apparatus with which they are supplied is suitable.

The second line of research is being followed by the Bureau of Plant Industry, assisted by the Bureau of Chemistry, and is concerned with plants other than trees. Private investigations are also being carried on.

The following five requirements are given by the Bureau of Plant Industry, Circular No. 82, as to the availability of crop plants:

1. They must exist in large quantities.

2. They must be available throughout the year.

3. They must yield a relatively high percentage of cellulose.

4. The fiber cells or cellulose, must be of a highly resistant character, and must have length, strength and good felting qualities.

5. And must be of such a nature that the cost of obtaining the fiber will not be prohibitive.

Fibers complying with these conditions will come into commercial use whenever the increasing costs of wood-pulp reach a figure approximately equal to cost of producing cellulose from any other available source. Up to the present time this has not been brought about, but the steady increase in the cost of wood-pulp is approaching a level with which crop pulps may soon compete.

A synopsis of the fibers described in the circular referred to is given below.

Corn Stalks.—On account of the enormous supply, corn stalks were first taken up by the Bureau. The yield of stalks per acre is conservatively estimated at one ton, and the annual product is placed as at least 100,000,000 tons, of which not over one-third is believed to be utilized by the farmers. Three products have been derived from the stalks:

1. Long fiber suitable for paper-making, composing 12 to 18 per cent of the bone-dry weight.

2. Pith pulp, suitable for paper specialties, equal to 15 to 30 per cent bone-dry weight.

3. Corn-stalk extract, obtained by lixivaition, and of value as a cattle food, a ton of stalks yielding 200 to 300 pounds of soluble solids.

It would require an immense area to supply a mill of moderate capacity, and the question of whether the derivatives of corn stalks could be sufficiently valuable to overcome the costs of harvesting and hauling, has never been answered by any experiment on a commercial scale.

Broom Corn.—Broom corn contains a higher percentage of fibers than corn stalks. In laboratory and semi-commercial tests, fiber yields of 32 to 40 per cent have been obtained with a comparatively low consumption of chemicals. The Bureau claims that results “indicate that this material is suitable for immediate use in paper-making on the basis of quality of fiber produced and yield of fiber secured.” It is estimated that 450,000 tons is the approximate annual crop. Food extracts may also be obtained as well as the fiber.

Rice Straw.—The Chinese and Japanese have for years used rice straw in paper-making, and it is regarded by the Government investigators as one of the most promising crop materials, the annual crop approximating 1,500,000 tons.

Cotton-hull Fiber.—The lint adhering to the cotton hulls, after the long fiber has been removed, may be conserved as a by-product of the cotton-seed oil industry, and this fiber may be reckoned among the possibilities. Cotton stalks also have been the subject of experiment. The yield per acre, however, is not estimated at above 1,000 pounds, so that immense tracts would have to be covered in accumulating any considerable supply, and after the cotton crop has all been picked, negro help is very difficult to obtain.

Bagasse.—Bagasse, or the refuse sugar-cane, is given rather scant consideration in the Government report. Its individual fibers are short, and the percentage of pith is large. Several small plants have had discouraging experiences in attempting to put this material to commercial use. Nevertheless, recent experiments carried on in the interests of the United Fruit Company, under the Simmons patents, point to a promising result. Under this process the cane is not treated in the usual manner of crushing for the extraction of sugar. Instead, it is shredded, dried, and the pith separated from the fiber. The product is then shipped in bales to refineries, where the sugar is extracted.

This method is said to achieve an almost complete extraction of the sugar, whereas the old method of crushing loses about twenty per cent of the sugar and injures the fibers. The Simmons process does no damage to the fibers, which though short, possess excellent felting properties. The pith, being cellulose of a non-fibrous structure, has a value for other industries than paper-making.

Flax Straw.—There is an abundant annual crop of flax straw. The average yield per acre is about one ton, and the total annual production about 3,000,000 tons. In the opinion of the Government investigators, it is a “most promising” material.

There are practical pulp men who deprecate the findings of the Bureau of Plant Industry. Martin L. Griffin, chemist to the Oxford Paper Company, of Rumford, Maine, in an article appearing in Volume XI, No. 2, of Paper for March, 1913, makes the following statement:

“There is a popular view, which has been erroneously fostered by the Government, that there are exhaustless resources of waste fiber in our country, suitable for paper, and a substitute for wood. I once thought so myself. It is very natural to think that the discarded stalks of sugar-cane, corn, cotton, rice, flax, and other plants, which mature annually, would prove an abundant substitute for wood.

“These have all been exploited for twenty-five years to my personal knowledge, with no visible results. A plant has one function to perform—it is to flower, fruit or make stalk. Its other functions are subordinate and produce only by-products. The stalk is the main product of the forest tree. No other fibrous material is so rich in cellulose; no other which lends itself so easily to paper-mill processing. It has no seasons of harvest; does not require curing; does not easily decay; requires no packing, and may be stored best in the rivers. All these waste stalks are pithy, bulky and perishable, and would require much labor to gather, pack and ship. These are but a few reasons why we may expect no practical results from this source. Wood fills a place no other material can. There is no substitute for it.”

In this argument Mr. Griffin ignores the fact that esparto grass is a crop which gives a yield of cellulose practically equal to wood, and of equal, if not superior, quality. Although it is not available for American mills, it is worth citing in contradiction to the flat statement that “there is no substitute for wood.” Furthermore, there is no evidence that the American crops furnish an inferior fiber, though the cellulose yield is less. It is quite possible that the low cellulose yield may be compensated for through the production of by-products along with the paper-making material. Hitherto, however, this low yield and other considerations, as expense of harvesting and packing, have been the factors which have retarded their development, but the increasing scarcity of wood, and its consequent advance in cost, is hastening the day when crop plants will become not only valuable, but necessary adjuncts to the paper industry.

RAGROOM, PIONEER MILL, CRANE & CO.

The two girls in the foreground are sorting shirt cuttings. Those beyond are cutting them into suitable sizes preparatory to boiling.

CHAPTER FOUR
THE CONSTITUENTS OF PAPER

The technique of paper-making varies greatly in accordance with each particular product. In fact, so wide is the range of paper products, that the different branches of paper-making severally require knowledge so special that an artisan in one branch might be as useless in another as if it were an entirely different industry. The coating of paper, for example, is an absolutely different trade from that of paper-making.

This remarkable diversification is entirely the development of a century, and principally the evolution of the past forty years consequent to the discovery of wood cellulose. To-day the products of the paper-mill are no longer confined to the use of pen or press. We ride on car wheels made in part of paper; sit in paper-seated chairs; drink from paper cups; eat from paper plates; use paper napkins; wrap our food in parchment paper; sheath our buildings with paper without, and wall paper or wall board within; keep out the rain with roofing paper if we please. Our shoes, even, contain a paper part, said to be more durable than leather. Millions of packages, mailing-tubes and boxes are made of paper. It is even spun into a kind of yarn and woven into imitation cloth, while a surprising imitation silk necktie is produced from wood-pulp. In electrical engineering, paper as an insulator is almost indispensable.

All these paper commodities, and more, too numerous to mention, require special machinery and treatment. To give an exhaustive treatment of the subject would require volumes, but for the purpose of this book we are principally concerned with printing and writing papers.

BOILER ROOM, CRANE & CO.

The contents of the rotary boiler have been emptied upon the floor. The next step is to wash and bleach.

Broadly speaking, there are five steps in the manufacture of paper:

1. The isolation of the paper-making fiber from the raw material.

2. The conversion of the fiber into pulp.

3. The beating and refining of the fiber, and the admixture of non-fibrous components.

4. The manufacture of the mixture into paper.

5. The finishing of the paper and its preparation for the market.

Cotton and linen rags, hemp, woods and plants each require their peculiar treatments. Cotton and linen, being the original paper-making fibers, will be considered first.

RAG STOCK.

Rag papers may be made from all sorts and conditions of rags, so the fineness of the finished product depends upon the newness and quality of the rags. New white cuttings from textile factories are the best, as their strength is unimpaired by previous use, and they may be prepared for manufacture with a minimum use of chemicals.

From this high standard, rags are graded down in accordance with their color, cleanliness and condition. The first sortings are made by stock-dealers, and the paper-maker orders whatever grades are suitable to his purpose. After their receipt at the mill, the bales of rags are opened, dusted by machine and distributed to girls, who sort them, open up the seams so as to release hidden dirt, remove buttons and other foreign material.

In the making of the highest grades, the new white rags are cut by hand into small pieces of uniform size, but ordinarily they are fed into a mechanical rag cutter. After this they are passed through a dusting machine to rid them as far as possible from dirt and foreign matter, which might otherwise appear as specks in the paper.

Boiling.—Dyes and greasy matters are associated with the fibers, and in order to obtain the pure cellulose fiber the rags are cooked, under steam pressure, in rotary boilers with alkali. This saponifies and dissolves the non-cellulose compounds, and the soda in combination with these soluble materials is subsequently washed out. The amount of steam pressure, the quantity of chemicals, and the duration of the cooking, are subject to variation under different conditions. At the conclusion of the process the manholes in the boilers are opened, and the contents are deposited on the floor, later to be transferred to the washer room.

Washing.—A washing engine consists of an oval tub about four feet high. It is divided longitudinally by a partition or “mid-feather,” with a passage left at either end for the circulation of the stock. On one side is located a large roll, having a continuous parallel series of knives horizontally inserted in its surface. The floor of the engine slopes gently to a point under the roll, where a bed plate is set. Behind the roll is a raised partition or dam, over which the stock is thrown as it passes between the beater roll and the bed plate. This is known as the “back-fall,” and assists in the circulation. The roll may be raised or lowered over the bed plate, and by this means the breaking of the stock is regulated.

Affixed to the tub are one or more washing cylinders, so arranged that they may be lowered into the stock. These are constructed in such a way that during the process of washing the water passes through their wire-covered surfaces and is drained into the hollow axle of the roll by an interior arrangement, called buckets. The axle, being open at one end, permits the wash water to escape.

At first the engine is partly filled with water, then the rags are gradually thrown in until the tub is full. The revolving roll keeps the mass in circulation, while the rags are broken and shredded as they pass beneath it. A continuous stream of fresh water runs into the tub, and in running out through the revolving washer drums carries off the dirt, but the fibers themselves can not pass through the wire coverings, so remain until cleansed. Necessarily the water used must be free from sediment or mineral impurities, such as iron, otherwise it would fill the stock with specks. Therefore, a filter plant is usually maintained.

Bleaching.—After the washing has been completed the drums are raised clear of the stock and bleaching liquor is introduced. This is an important step, and if not carefully managed may impair the stock. For instance, if bleaching is carried on at too high a temperature, the white color obtained will not be permanent, and discoloration will occur after the paper is made. Much of the paper, which at first displays a brilliant white color, will afterward take on a yellowish tinge, especially if it is exposed to light. A comparison between the century-old hand-made papers and modern “fine writings,” makes the old papers appear a “natural” shade, but place both for a few hours in the sunlight and often the modern paper will fade, whereas the old sun-bleached papers remain unaltered. The high artificial bleaching does not insure permanent results.

After the bleach liquor has been thoroughly mixed in, the stock is discharged into drainers and allowed to stand for a week or more, until no traces of chlorine remain. In this state the pulp is known as “half-stock.”

The treatment of hemp is so similar to that of rags that a description here of the process is superfluous.

WOOD-PULPS.

Wood-pulps are of two classes, mechanical and chemical. In the lay mind there often appears to be some confusion between the two, leading to an unreasonable prejudice against papers made from either class. The fact is so generally known that news-print, one of the cheapest grades of paper, is made from wood, that the partially informed person is prone to think that all wood papers are of low quality, whereas paper of permanence and excellent quality may be made from the high grades of wood cellulose chemically prepared.

Ground Wood.—The mechanical, or ground wood, as its name implies, is made by grinding logs from which the bark has been removed. The logs are shipped, or floated from the lumber camps to the mills, where they are cut to convenient length and the bark is removed. Next they are taken to the grinders. One type of grinder consists of a vertical grindstone encased in an iron jacket. There are three pockets over its circumference into which the logs are placed. They are held by hydraulic pressure against the revolving stone, over which flows a stream of water, and are rapidly reduced to fibers. These fibers are carried by the flowing water into a chamber below the grinders, passing through a screen which catches the coarser bits, the fibers of suitable size thus being separated from the rest. This pulp is still not sufficiently fine or uniform, so it is pumped into screens and forced through the finely perforated plates. The fibers are carried through with a large quantity of water, and are formed into thick sheets by means of a so-called “wet machine.”

Wet Machine.—The wet machine consists of a vat, in which a partially submerged hollow drum rotates. The surface is covered by a wire cloth, and the hollow axle of the drum acts as a drain for the fiber-laden water, which, in passing through the drum, deposits a film of fibers upon the revolving surface. This soft pulp film, continuously forming, is removed from the top of the drum by an endless felt running tangent to it, and held in close contact with it by a couch roll, the pressure of which causes the web of pulp to adhere to the felt.

The felt passes between two squeeze rolls, and the pulp adhering to the upper roll is wound up until a certain number of layers have accumulated, when it is cut across by a knife and removed as a thick sheet.

WOOD GRINDER

The sheets, folded to a convenient size, separated by alternate pieces of sacking, are put in a hydraulic press and squeezed to remove the water. The pulp is taken from the press about fifty per cent moist; the sheets are separated from the sacking and are now ready for use or for shipment. It is also quite customary to ship the pulp without having pressed it. In this case it contains about 70% water, due allowance for which is made in billing.

This pulp contains practically all the constituents of the original wood, has little strength, inferior felting properties, and is not of permanent character. Its utility results largely from its cheapness. When made into paper with a suitable admixture of sulphite pulp, for strength’s sake, it proves to be admirably adapted for the fast-running newspaper presses, as ink dries upon it almost instantly.

It is also used in the making of boxboards, cheap cardboards, pie plates, wall papers, etc. It should, however, be strictly excluded from all papers of more than ephemeral purposes, because of its lack of permanence. The appearance of a paper containing much ground wood is inferior, as the color is poor and small shives of wood may be discerned on the surface. An easy and reliable way to ascertain the presence of ground wood is to moisten the paper with a drop of strong nitric acid, which develops a dark-brown stain if ground wood is present. Another good test is phloroglucine, which turns ground wood to a bright carmine shade. The quantity of ground wood is roughly indicated by the intensity of the stain.

BLEACHED GROUND WOOD

A quality of pulp intermediate between chemically produced wood cellulose and ground wood is obtained by bleaching an especially finely ground quality of pulp wood. This product is excellent as a filler for medium grades of paper, as it is opaque—fine, and of fair color. Nevertheless, it is open to the same criticism as other ground wood as to permanence, though in a less degree.

CHAPTER FIVE
THE CONSTITUENTS OF PAPER—Continued

Chemical Wood-pulps.—Chemical wood-pulps are obtained by a variety of processes, all of which have as their object the isolation of the pure cellulose fiber by the dissolution of non-cellulose components. The same principles are applied to the treatment of esparto straw or other plants. The character of the pulp depends not only upon the nature of the wood, but also upon the solvents used and the duration and severity of the cooking.

The preparatory steps to any process by which chemical wood-pulp is made are identical with the preparation of trees for ground wood, only after the logs have been “barked,” they are reduced to chips by a mechanical “chipper.” The ordinary practice in America is to sort out any knotty or imperfect logs as they pass on a conveyor from the “barker,” and if the log it too faulty it is discarded. As it is desirable to have a uniform size of chips, the chips are passed through a screen for this purpose.

The chips are stored in bins convenient to the digesters. The digesters are of two types, rotary and stationary. The rotary type is horizontal and the stationary is vertical.

After the digester has been loaded with chips, the chemicals are introduced and the “cook” is carried on by means of high steam pressure. The strength of the chemicals, pressure of steam, and duration of cooking, are the principal factors in determining the result from any particular wood. Slow cooking at low temperatures yields the best results.

WET MACHINES WHERE THE PULP IS CUT OFF IN SHEETS, THE BROWN CO.

To the right are the hydraulic presses for removing moisture from the pulp. The pulp is shipped about seventy per cent moist.

Soda Pulp.—Soda pulp takes its name from the caustic soda which is used as a solvent. Rotary digesters are employed in its manufacture. The principal wood used for making soda pulp is poplar, though chestnut and aspen are also used. Soda pulp is soft in texture and of no great strength, but in combination with harder stocks it lends mellowness to the sheet. It is almost one-third cheaper than bleached sulphite pulp, quotations for February, 1915, being $2.20 to $2.35 per hundredweight, whereas bleached sulphite was quoted at $2.80 to $2.95 per hundredweight. The prices since the war have risen over 100% and were quoted in September 1919 at $4.75 to $5.00 and $5.75 to $6.25, respectively. One reason for the difference in price between soda and sulphite pulps, is that the soda is recovered from the spent liquor, whereas in the sulphite process the liquors go to waste.

Sulphate Pulp.—The solvent used in making sulphate pulp is a mixture of caustic soda, sulphide of soda and sulphate of soda. Sprucewood, largely, is used and the pulp produced is exceedingly strong. Unbleached sulphate pulp is used, notably, in the making of Kraft wrapping-paper. The soda is recovered from the spent liquors.

Sulphite Pulp.—Sulphite pulp is produced by the use of bisulphite of lime; this, being acid, necessitates a special brick lining in the digesters, which are of the vertical type. Sprucewood is the best raw material and yields a strong, fairly long fiber, capable of being bleached to a good white color.

Mitscherlich Pulp.—A special method for making sulphite pulp was invented in Germany by Professor Mitscherlich. It varies from the ordinary process in that the cook is continued over four times as long under lower steam pressure, and yields a fiber of greater strength.

The steps subsequent to cooking chemical pulps of all kinds are similar. After emptying the digesters, the soft, discolored mass of fibers is washed and bleached. The yield of cellulose fiber is close to fifty per cent of the air-dry weight of the wood. The shives and undigested particles are removed by screening, and the pulp is either run out like ground wood on wet machines, or made up into rolls, or sheets, on a paper-machine. The soda pulp is shipped in rolls and the sulphite in sheets, as this is the most favorable form in which to handle them at the paper-mill. If the pulp is to be used on the premises, it is made up into laps on the wet machine and is not artificially dried. The so-called “air dry” pulp contains about 10% moisture, and pulp containing not over this amount of moisture is billed at its actual weight.

CYLINDER MACHINE FOR DRYING PULP, THE BROWN CO.

The web of pulp is shown as it passes from the cylinder mold over the couch roll toward the driers.

Esparto and Straw.—Esparto pulp is made by the soda process from a grass obtained in the circum-Mediterranean countries, and is used most extensively in England and somewhat on the Continent, but freights have been prohibitive for American manufacturers.

Straw pulp is similarly made, and while occasionally used on medium grades of writing-papers, its principal use in this country is for strawboard and cheap wrappings. It is expensive to reduce to a clean, bleached pulp on account of its knots, and the large quantities of silicious matter it contains.

Waste Papers.—The next largest source of paper-making fibers to wood is the waste paper, such as old books, magazines, newspapers, binders’ waste, paper shavings and miscellaneous waste. This stock is collected by regular packers, sorted, and sold by grade to the mills.

The poorest grade consists of a mixture of miscellaneous papers of all colors and description. It is only used in the production of boxboards, sheathing paper, and other coarse varieties, and without undergoing any preliminary treatment it is shoveled right into the beaters.

A higher grade consists only of mixed papers, printed or unprinted. Next is a grade containing no ground wood or colored papers, and above this are graded old ledger and writing papers.

THE BEATER-ROOM, CRANE & CO.

The beater at the far end of the room is equipped with a washing drum. This drum is lowered into the tub during the process of washing.

Paper trimmings are divided into four classes, white and mixed, soft and hard “shavings,” and are especially available, as they may be used after sorting and dusting without undergoing further treatment, but it is customary to macerate them in some sort of a pulper before placing with other stock in the beaters. The printed waste must be boiled in a solution of soda ash. This makes the ink removable. After about six hours’ boiling, the stock is transferred to washers and treated like rags. The ink and dirt having first been removed, bleaching solution is introduced, and finally the stock is let down into drainers. In some mills the draining is omitted, the excess bleach is washed out and an antichlor added; then the stock is pumped over to a beating engine to be mixed with the other ingredients preparatory to manufacture. This process is less thorough, and there is more danger of getting residues of bleach into the paper, as it is rather a nice matter to exactly neutralize the bleach in the washer, and the maintenance of a uniform color is endangered.

Printers, or others, who accumulate large quantities of waste papers, will find that it pays to keep the various grades in separate receptacles, as a better price may be obtained for it in this way. Furthermore, by means of a baling press, the papers may be set aside in compact bales, which occupy less room and are not so great a fire risk as loose accumulations. The fact that 21.4 per cent of the paper-making fibers, according to United States Census Report, 1909, are derived from waste papers, indicates their importance as raw materials, while their use lessens the drain upon our forests.

THE NON-FIBROUS CONSTITUENTS OF PAPER.

The non-fibrous constituents of paper are the mineral fillers, the ingredients for sizing, and the coloring pigments and dyes. Mineral fillers should not be regarded as adulterants. They are used, not as a means for adding weight, but for the sake of certain effects which are requisite in many papers. No filler is used on good writings or ledgers, as the printing requirements do not call for a closely filled surface or a mellow texture.

In book papers a varying percentage of clay is used, as it improves the printing quality by filling up the interstices between the fibers and increases opacity. Papers for half-tone printing require more filling, in order to have smooth, level surfaces.

There are several kinds of filler in common use. The most common is China clay, of which the cleanest and finest grades are obtained principally in England. No equally good deposit has yet been successfully developed in this country. Clay is a product of the natural disintegration of feldspar. It is soft, plastic, and non-crystalline.

Agalite and talc, which are silicates of magnesia, are also used. They are cheaper and less desirable, both on account of color and their crystalline nature, which is more or less damaging to cutter knives and printing-plates. These fillers are used widely in the cheaper book-papers, and can often be detected by holding a sheet against the light, as the little, translucent crystalline particles then appear like pinholes.

Sulphate of lime, commercially known under such names as gypsum, pearl hardening, satinite, etc., is a white, crystalline substance. This is used to some extent in paper-making, but principally as a coating.

Barium sulphate, prepared chemically, and known as blanc fixe, is used largely for coating papers because of its brilliancy and purity of color.

Sizing Materials.—Starch was one of the earliest materials used for sizing paper, and is used considerably in addition to other materials, as it adds a hard, tinny character desired by the trade on certain grades. Silicate of soda is also used to impart similar characteristics.

Gelatine, or animal size, is obtained by boiling down suitable animal tissues. As a sizing agent, it is applied after the paper is made by passing the web of paper through a vat containing the hot liquid size.

Casein, which is sometimes used as sizing, is more important in its functions as an adhesive for the making of coated paper. It is prepared by treating skim milk with weak acid.

Rosin size, the most widely used size, is produced from rosin by cooking with soda ash, which produces a soft soap. The soap when mixed with water by agitation assumes a milky appearance. In this condition it is poured into the beater after all other ingredients have entered, and is precipitated by the addition of alum as a resinate of alumina.

Impurities in Paper.—Impurities, either chemical or physical, are sometimes found in paper, owing to lax methods or inferior materials.

Free acid occasionally occurs, and in some cases would be very deleterious. In papers that are to be bronzed, for example, this acid would tarnish the bronze. Needle papers, and paper for wrapping steelware, must be acid-free, otherwise they will cause rusting. The presence of free acid may only be determined by an analyst.

Sulphur, which may give rise to the formation of sulphuretted hydrogen, exists sometimes as an impurity in paper. It causes a brownish halo to appear around printed letters, because of its action on printing-ink. It would also cause oxidization of jewelry, mounted upon cardboard containing sulphur residues.

Free chlorine, or chlorine compounds, the result of inadequate draining of the stock, may cause final disintegration in the paper. It is the duty of manufacturers to guard against this and the other deficiencies noted.

Mineral impurities in paper are not uncommon. Minute particles of iron worn off the machinery, or getting into the stock in the shape of wire stitching, can often be discovered by the use of a magnet test. In photographic papers this must positively be excluded, but in most papers, if the particles do not show as specks, and are not large enough to make trouble for the printer, they are not a serious menace.

CHAPTER SIX
PAPER-MAKING

We have now reviewed the various steps preparatory to the process of beating, and this process is perhaps the most important of all. The output of a mill depends, first, upon the quality of stock which is furnished to the beaters, and secondly, on the way the stock is handled in the beaters. A formula, better known as a “furnish,” is prepared by the superintendent and given to the beater engineer. This tells him exactly how to blend his raw materials. Very few papers are made from one kind of material alone, most papers being a mixture of different fibers, with the addition of mineral filler, sizing and coloring. All the ingredients are put together into the beating engine with a large volume of water similar to a washer, minus the washing drums.

BEATING.

The process is called beating because it has displaced the original method of maceration by mallets and later by the machine described in [Chapter I] as a “stamper.”

The ultimate characteristics of the paper are dependent upon the handling of the beater roll and the character of the knives. For example, a blotting-paper is made by a quick beating with sharp knives. This cuts the fibers clean and short and leaves them in a most absorptive condition. The very same fibers, treated with dull knives and slowly beaten, would have an entirely different character. Their ends would be teased out and ragged, and in the process of manufacture they would part very slowly from the water absorbed. The paper produced would have the characteristics of a writing-paper, hard and strong. This instance will afford some idea of the wide variation in results which may be brought about by varying the treatment in the beaters. So important is this step in manufacturing that it has been said with a good deal of truth that “the paper is made in the beaters.”

After the process has been continued a sufficient length of time, the stuff is emptied into a chest called the “Jordan chest,” because it acts as a reservoir for another type of refining engine known as the “Jordan.” This engine is conical in shape and the inside is lined with knives. A cone-shaped plug, also shod with knives, fits into this shell, and by the turn of a screw may either be moved in or out, thus varying the space between the two sets of knives. By this adjustment the refining of the pulp which flows through the engine is regulated.

The stock passes through one or more of these “Jordans” into the machine chest. Thence it is pumped to a level higher than the machine, and flows through “sand settlers” to a screen. The “sand settler” is a long, open trough containing a series of baffle boards which collect any sediment, preventing it from getting into the paper.

Screens are of various types, the main feature consisting of bronze plates pierced with fine slots through which the fibers are forced. The object is to give uniformity to the stock which reaches the machine, and to exclude any knots of stock, strings or foreign substances.

The width of the slots is varied to suit different stocks—some slots being as fine as 10/1000 of an inch.

We have now described the process of paper-making up to the point where the stuff is formed into paper, and must pause for a description of the paper-machine itself.

PAPER-MACHINE.

The paper-machine may be considered in three parts: The wet end where the paper is formed and pressed, the middle, where it is dried, and the dry end, where it is calendered, slit and wound.

There are two distinct types of wet ends—the Fourdrinier and the cylinder. Both are mechanical reproductions in continuous process of the steps taken in the ancient hand methods, a brief consideration of which impresses clearly on one’s mind the rationale of the machine.

HAND PROCESS.

The tools of the primitive paper-maker consisted of a pulp vat for the fiber-laden water, a frame, or mold, across which was stretched a mesh of closely woven wire, and a removable frame, known as the deckle, which fitted around the edge of the mold to keep the moist pulp from overflowing and to help regulate the thickness of the paper.

Grasping the mold by two opposite sides, the vatman submerged the mold in the water; then raised it out, holding it level. By this means a film of pulp was caught up, being deposited on the bottom of the mold by the passage of the water in which the fibers had been suspended. A lateral shaking motion served to knit the fibers together, and to deposit them as evenly formed as possible all over the mold. As the water drained through, the film of pulp solidified. Then the deckle frame was removed, and there, on the top of the mold, was a sheet of moist pulp. The edges of this sheet would be thin and feather-like as a result of the pulp leaking under the deckle. Hence the term deckle edge.

It required a great deal of skill to remove this film, while preserving it intact. This was accomplished by inverting the mold and pressing the sheet upon a moist felt cloth. If the act was skilfully performed, the mold could be lifted away from the sheet, leaving it unbroken upon the felt. Then it was covered by a second piece of felt and the process was repeated until a small pile had accumulated.

The pile was removed to a screw press, wherein as much water as possible was squeezed out of the paper. Cellulose fibers have a strong affinity for water, however, and it is said that under any pressure which such a pile could withstand, without becoming crushed and gruelly, the paper would retain water equal to one-half its weight. Hence, the last vestiges of moisture, excepting of course that amount normally retained by air-dried paper, had to be removed by evaporation. In the old days, this was accomplished by hanging the sheets over poles to dry.

After that, if the paper required sizing, the sheets were dipped one by one into a pot of animal size, then dried once more. Lastly they were finished to the desired surface by being placed between smooth plates and pressed.

FIBER CHARACTERISTICS.

A few moments’ consideration of the changes which the fibers undergo from their condition of isolation as they exist mixed in the vat, to their status as components of a sheet of paper, will help to make clear much that seems obscure about the behavior of a sheet of finished paper, as well as to explain the reason for the different processes executed on the paper-machine.

The fiber is a hollow, collapsed tube, the ends bruised and frayed by the treatment in the beating and refining engines. Absorptive in nature to a marked degree, it swells with the water it takes up and is limp and flaccid. As the mold is raised horizontally out of the vat in the process of forming sheets, all the fibers which had been suspended in the water which passed through the meshes of the mold are caught like so many fish in a net, and lie spread in a limp, impressionable mass over the surface of the mold until they are transferred by the “coucher man” to the felt. Little alteration can take place in the general position of the fibers after they have been “couched,” consequently the formation of the sheet is the most important stage of the process. As the water is pressed out, each fiber contracts to some extent, and, from a consistency like gruel, the formed sheet passes to a more stable state, wherein it can be gently handled without disintegrating.

FOURDRINIER MACHINES, CRANE & CO.

A good view of the surface-sizing vat is obtained in the machine on the right hand. The paper is being slit just before its introduction into the vat.

As the drying proceeds there is a marked shrinkage in the dimensions of the sheet, caused by the shrinking of each individual fiber, until the fibers are thoroughly set, enmeshed one with the other.

The addition of size glazes over each fiber and makes it less susceptible to moisture. The addition of clay permeates the structure, filling up the interstices. Up to a certain point the clay does not materially weaken the structure, as a certain percentage of empty air space would exist without it. Beyond that point the clay will fill places that conceivably would be filled by fibers, and having no adhesive strength, the structure of a sheet overloaded with clay is weakened in proportion to its overload.

While the fibers are more or less moist, they are susceptible to alteration in structure, and may in this state be flattened by calendering to a smooth surface, and the presence of clay helps to fill in the microscopic valleys between the fibers so that the surface becomes level to human vision.

THE FOURDRINIER

Now to return to a sketch of the wet ends of paper-machines. The Fourdrinier part consists of a head box, which resembles the case of an upright piano. Where the keyboard might be, is a broad portal for the passage of a stream of pulp, the width of the machine, onto a horizontal, endless wire belt. This wire belt is suspended in a frame some thirty feet long and held taut by being stretched over a number of rolls. The large roll near the head box is known as the breast roll. The still larger roll at the other extreme of the frame is called the lower couch roll, on top of which is a felt-jacketed couch roll. The wire is kept level by a transverse series of “table rolls” closely set, and the under part of the wire is held down by stretch rolls. Directly under the top part, and continuing from the breast roll for about two-thirds the length of the frame, is a shallow tray called a “save-all,” as it catches all the drippings which contain filler, and some fine fibers which are returned to the screens by stuff-pumps, maintaining a continuous circulation so that nothing goes to waste. Into this save-all water may be admitted to regulate the consistency of the stuff.

Near the couch roll the wire passes over two or three suction boxes, and on top of the wire, between the suction boxes, turns a wire-covered roll called a “dandy.”

On either side of the machine is a frame which may be contracted or expanded. It carries a series of pulleys over which run rubber deckle straps, the under parts of which rest on the wire and keep the wet pulp within bounds. By this means the width of the web of paper is regulated. As a little pulp leaks under these straps machine-made paper has deckle edges on both sides of the web. Artificial deckle edges may also be produced by squirting a fine stream of water upon the web near the couch roll, but it is not possible to produce this effect across the web. Except on special papers the deckle edges are trimmed off by slitters at the end of the machine.

Near the flow box, running at right angles across the machine, are two so-called “slices” about eight inches apart. These may be adjusted at various heights from the wire, in order to regulate the thickness of the paper. Their most important function is to make the thickness uniform from one side to the other of the sheet, and to create a pond which assists in forming the paper.

The frame of the Fourdrinier has a joint near the first suction box, and a mechanical arrangement called a “shake” is located near the head box to impart a lateral shaking motion to the frame while the wire runs straight ahead, thus imitating the shaking of the hand mold.

Beyond the couch roll is a series of press rolls, between which run endless felts to carry the soft, moist paper.

Then follows a large series of steam-heated cylinders. Next a stack of iron calender rolls, and a set of reels. As soon as one reel is full a new reel is started and the paper from the first reel is slit by rotary slitters and made up into rolls of the desired widths on the winder.

PAPER IN PROCESS

It is an almost dramatic moment when the machine is ready to start. The machine tender opens the valves which admit the stuff from the flow box and a stream spreads out onto the wire. At a given signal the back tender starts the wire, and the endless white stream moves smartly forward. Then ensues the mechanical imitation of making paper by hand, only instead of forming sheet by sheet, the formation is a continuous process in the web. The shake of the machine mixes the position of the fibers in the “pond” behind the slices; the water runs like a downpour of rain through the moving wire into the save-all, leaving behind its burden of fiber, or “stuff,” as the mixture is at that stage called, in a white film.

The suction boxes accelerate the expulsion of water, and the dandy roll closes the fibers together as the film passes beneath it. Then the web is carried between the couch rolls, when the water fairly pours out in the squeeze. As the top roll is felt-jacketed, the film sometimes sticks to it, as a slight suction is created in the pores of the felt. The back tender stands by with a hose to wash down the paper if it starts to adhere to the jacket. The paper is prevented from completely going around this top roll by a guard board which is fixed across the top. Many machines are now equipped with a “suction couch roll,” which does away with the need for a top roll, as the water is sucked, instead of pressed, out of the paper.

At a given signal the back tender starts one edge of the film forward, by a skilful slap of the hand, which picks up the edge of the film and transfers it to the felt carrier between the press rolls. The remainder of the web is made to follow the lead of the first section, till finally the full width is transferred to the first felt, which carries it through the first series of press rolls.

An arrangement similar to the guard board, called a “doctor,” runs across the top press roll, so that the paper may be allowed to roll up if desired, while the machine tender regulates the flow of water until the consistency of the stuff is right. The doctor also keeps the press roll clean. Quite often the long end of paper first started at the couch roll is passed right along from the first felt to the second, carried through the second set of press rolls, and the third, if three there be, to the steam driers, and thence over the entire battery of driers, through the calenders onto the reel.

From the press rolls it is led by the back tender, assisted by a third hand, and if all goes well the paper may be winding up on the reel inside of ten minutes.

But there is many a chance for mishaps before the wet end of the machine is adjusted and the heat in the driers is regulated to a nicety.

The weight of the paper depends upon the quantity of stuff let onto the machine, the dilution of the stock, and the speed at which the machine is run. Given a certain volume, the faster the wire runs the thinner the stuff is spread, and vice versa. Before things are settled down, considerable worthless paper may be turned off.

The width of the web is controlled by the distance between the deckle straps. These are adjustable, but an allowance of ten inches or so must be made for the shrinkage of the web in drying.

The preliminaries to a run of paper may be likened to the make-ready on a printing-press, though they do not, as a rule, last nearly so long. Yet this is the reason why small odd sizes and odd shades of paper are not popular with the manufacturer, unless he can get a sufficient extra price to compensate for the “make-ready” costs.

Water-marks.[C]—The water-mark in paper is effected by raised lines on the dandy roll. The design, being impressed in the moist web, displaces the fibers and leaves thin areas in the paper, which consequently show when the sheet is held against the light, as they are more translucent than the adjoining areas.

[C] The study of ancient water-marks is quite fascinating in connection with early Printers’ marks. See “A New Light on the Renaissance,” by Harold Bailey.

FOURDRINIER MACHINE, S. D. WARREN & CO.

View showing the “Fourdrinier” part of a modern book paper-machine.

CHAPTER SEVEN
PAPER-MAKING—Continued

Technique.—The importance of the formation of the sheet on the machine wire is the same as on the hand mold, as subsequent pressing and calendering can only modify faulty formation. The stuff should be uniform and even in texture. The press rolls must be ground with absolute accuracy, and slightly crowned to allow for their sagging. Otherwise water would be unevenly expelled from the web, possibly causing a damp streak throughout the entire run of paper, which would show in the finished product.

If a portion were pressed too hard it would contain less moisture as it reached the driers and become dry before adjacent sections. If the paper were calendered, the moister parts would take on a smoother surface than the drier parts.

Another feature to be closely watched on particular papers is to eliminate, as far as possible, the impress of the weave of the wire cloth, which is left in the under side of the web. This can be accomplished to so fine a degree, by a skilful man, that the difference between the two sides of the paper is scarcely discernible. The fineness of weave of the one cloth also is an important bearing in securing an even sided sheet.

Thus we see that it is well-nigh impossible to reduce the making of paper to an exact science, and a reasonable variation must be expected, both in weight and finish. The successful management of a paper-machine depends, from start to finish, on careful, experienced judgment and alert attention. If the beater-man dilutes one batch of stuff more than another, the variation will show the minute the altered stuff appears on the machine, and only an immediate readjustment at the wet end can avoid considerable variation in the product. Then, from end to end, the long machine must be watched carefully, so that the pressing, drying and calendering may all be kept uniform. A bungler should find no place in the machine-room, but it is desirable that consumers have sufficient appreciation of human limitations, as applied to paper-making, to admit proper allowances for normal variations.

Cylinder Machine.—The cylinder machine, invented by John Dickinson about ten years after the Fourdrinier, is much the same as the wet machine described in [Chapter II], with the addition of press rolls, driers and calenders. The single-cylinder machine is used for making light-weight tissues and other thin papers. Cylinder vats can also be arranged in series, as on board machines, so that the webs formed on each cylinder can be combined. This is accomplished by an arrangement of felts which run tangent to the cylinders, picking off the formed paper automatically from each successive mold.

The felt runs between squeeze rolls, so that the various plies of paper are pressed together, forming a single thickness. Machines of this type can make very thick sheets, and are used for making bristol boards, blanks, boxboard, strawboard, etc.

The number and arrangement of driers on any machine depends on the product to be derived. Fast-running machines, such as the large news mills are equipped with, have necessarily a large number of driers, as they turn off fifty tons or so a day and require a great drying capacity. Slow running machines, such as are used in fine writing-paper mills, need a much smaller number, as the average fine writing-paper machine produces little over three or four tons a day.

CYLINDER VATS, MADE BY THE PUSEY & JONES CO.

The felts which convey the paper are omitted so as to get a clearer view of the molds.

Harper Machine.—There is a type of Fourdrinier called the Harper which differs from it in that it is turned end for end. A long felt carries the paper from the couch rolls back over the Fourdrinier part, delivering it to the first press. This is considered advantageous in making very light papers which otherwise are with difficulty led from the couch to the press rolls and are apt to break down in the passage.

Yankee Machine.—There is even one type of machine known as the “Yankee” which has but one drier of very large diameter. This is used in making machine-glazed wrapping papers, which are very smooth on the side of the sheet which comes in contact with the drier and rough on the other side. The “wet” end of this machine is a Fourdrinier type.

The arrangement and number of smoothing and calender rolls is also dependent on the class of paper to be made. Most writing-paper machines have no calenders at all as the surface is obtained on special machinery such as platers and sheet calenders after the paper comes from the drying loft. One can easily appreciate that, while the general principles of all paper-making are identical, there is a call for a wide variety of arrangements, such as those cited, to meet the varying requirements of different classes of paper.

Surface Sizing.—Surface sizing, or animal sizing, necessitates a vat with squeeze rolls. The paper is first run over enough driers to dry it; then introduced into the vat of hot size. On the cheaper grades the size is dried on the machine by a special skeleton drying apparatus, but the better grades are cut off and piled up by the “lay-boy” at the end of the machine, then transferred to drying lofts and hung up over poles to dry. Hence the term “loft-dried.” Any special finish has then to be applied sheet by sheet.

Finishing Paper.—Finishing paper is accomplished either on the paper-machine itself, or after the paper is turned off on the machine it may be treated by special apparatus.

Wove and Laid Papers.—A so-called wove paper is made with a plain dandy, covered with fine wire cloth the same texture all over. Laid paper is really a water-marked paper, in which the whole surface is marked by a specially constructed dandy which imprints a mark in imitation of the early hand molds. There are heavy lines running with the grain of the paper and lighter lines running across.

Antique.—An “antique” surface is obtained by skipping the calender rolls and leaving the paper rough as it comes off the felt to the driers. A medium finish is obtained by a slight calendering, while the highest machine finish, and the so-called English finish, is obtained by a heavy calendering.

Water Finish.—A common method of obtaining a high finish on heavy papers is by the use of “water doctors,” which keeps two or more of the calender rolls moist, dampening the paper while it is being calendered. The surface thus imparted is called a “water finish.”

SHEET CALENDERS

Fine writing-papers may be finished in a variety of ways. A plain, smoothed surface is obtained by passing the sheets, which are automatically fed, by a system of tapes, through calender stacks, called sheet calenders.