PAPAVERACEE

PAPER

Papavera'ceæ. See POPPY.

Papaw', (1) fruit of a small tropical American tree (Carica papaya) of the family Passifloraceae; has an acrid quality, and when boiled with meats renders them tender. The juice, at least before the fruit is ripe, contains a remarkable albuminous substance resembling or

PAPAW.

identical with fibrin, is anthelmintic, and has detergent powers. (2) In the U. S. the name papaw, or pawpaw, is given to Asimina triloba, parviflora, grandiflora, and pygmæa, handsome shrubs, or the first a small tree, of the family Anonacea. The pulpy fruit of the first mentioned is edible, but is not generally esteemed.

Papayotin (păp-a-yo'tin), substance derived from a plant called Carica papaya, the juice of which is capable of transforming proteids into peptones; supposed to differ from pepsin not only in its vegetable origin, but also because it acts in the presence of either an alkali or acid; other derivatives of the juice have been introduced into medicine, the chief of which are papain and papoid.

Pa'per, a substance made in the form of sheets or leaves, in varying thicknesses, and employed for writing or printing upon; also for wrapping purposes, and in the manufacture of various articles of common use or

of industrial and scientific application. Vegetable fiber is the base and chief component of the article of commerce known as paper. This is used in various forms and with different intermixtures, animal as well as mineral fibers being at times incorporated into its substance, with loading or filling material and coloring matter. In its pure state vegetable fiber is known as cellulose. It is white, translucent, slightly heavier than water, without taste or odor, and is insoluble in all simple solvents; its chemical formula is C,H10O5. The fibers chiefly used in the manufacture of paper are those of cotton, bast (as linen, jute, and hemp), those derived from whole stems or leaves and associated with various vessels and cells not properly fibers (as straw,

those derived from wood. Paper derives its name from an aquatic plant, the papyrus which grew in Egypt. The material obtained from this plant was the first product, so far as known to us (except the wasp's nest), resembling that which we call paper. The manufacture originated with the Egyptians at least two thousand years before the Christian era. The Egyptian reed held undisputed command of the market for hundreds of years; in Europe till the twelfth century attempts were made to supersede it, notably by the use of parchment, but success in this direction was not attained until the introduction of paper made from cotton fiber. The Chinese are credited with the discovery of the art of paper making by the use of fibers reduced to a pulp in water. Their raw materials were the inner bark of the mulberry tree, bamboo, rice straw, rags, etc.

In the making of "hand-made " paper, the pulp, which has been prepared by machines, is mixed in a vat with water to the necessary degree of diluteness, after which the work of the person who makes the sheet of paper begins. This workman has a mold or sieve covered on one side with fine wire cloth and a movable frame, called the deckle, both forming a shallow tray. The vatman takes a mold and lays upon it the deckle; he then dips the mold into the pulp, which is kept uniformly mixed with the water in the vat by means of an agitator, and lifts up as much of the pulp as will form a sheet of paper; to this he gives a shake from him and back again, and then from right to left and back again; this done, he transfers the mold to his assistant. The assistant turns the mold upside down on a piece of woolen felt, and places another piece of felt on the sheet of paper thus deposited. The felts and sheets of paper are alternated until a pile is formed, which is then submitted to great pressure. Then this pressure is taken off, the felts and sheets of paper are drawn out and laid in separate piles. The paper is afterwards put into another press to remove the felt marks and to get rid of more moisture; it is next hung up, sheet by sheet, to dry, after which it is sized with gelatin. The paper is again pressed, dried, sorted, counted, packed, and in this finished condition goes to market.

In the U. S. to-day paper is almost universally made by machinery. If rags form the original material, they are sorted, cleaned, cut into small pieces, and then boiled in steam. After draining, the cooked rags are taken to the engine room, and are there washed by a stream of water through the washing engine until the water runs clear. The washing engine consists of an oblong tub of wood or iron, rounded at the ends. It is made in various

sizes, to accommodate from 100 to 1,500 lb. of rags. In the center of the tub there is a partition, the "midfeather," with a passageway at each end for the circulation of the water and rags through the engine. On one side of the "midfeather," occupying the space between it and the wall of the tub, is a cylinder or roll set with a series of steel knives,

PAPER

and beneath this roll is a bed plate, also furnished with steel knives and set in the floor of the trough, which at this point rises with an inclination to and surrounding the roll at a short distance therefrom, and then drops in an inclined plane known as the 'backfall" to the level of the tub bottom. On the other side of the "midfeather" the floor of the tub is flat and level with the ends, and on this side is located the washing apparatus, which consists of one or two cylinders, whose framework is covered with wire gauze. The roll and the washing cylinders are mounted in such a manner as to be raised or lowered at both ends. When the washing is going on the

FIG. 1.-PAPER MILL OF THE SIXTEENTH CENTURY.

washing cylinder is partially submerged in the contents of the engine, the water which passes through its gauze covering being discharged through an opening in the journal which rotates it. During the process of washing the stock or material is also treated in such a way by the knives on the engine roll that the fibers are separated and drawn out so as to be long and flexible.

In some mills the stock is bleached in an engine intermediate between the washing engine and the beating engine; in others the bleaching is done in the washing engine. It is effected by adding to the "half stuff" in the engine a solution of bleaching powder (chloride of lime).

The next operation is that of beating, in which process the "half stuff" is reduced to that stage of fineness requisite to convert it into paper. The beating engine is of the same type and form as the washing engine, but it is provided with sharper knives and the roll is set down closer to the bed plate. The cylinder washer is employed for a short time to wash out the bleaching solution. The beating

PAPER

is then continued until the fibers are reduced to the proper length. Next follows the sizing, if engine-sized papers are to be made; also the loading." The material used for loading or filling purposes not only adds to the weight, but further serves the useful purpose of filling the pores and giving a finer surface to the paper when it is finished. The ordinary filling is china clay, but other substances are also employed. Engine sizing consists in adding to the pulp a resin soap made by boiling powdered resin with soda ash, or crystals of soda, the alkali having been previously dissolved in water. If not thus sized the paper is treated with animal size, as described below, or it may be both engine sized and animal sized. The coloring material is also applied in the beating engine, or in making white papers the pulp is given an addition of ultramarine or other necessary color, mixed in water and strained.

At this stage the pulp is emptied from the beating engine into large cylindrical vats, in which more water is added to the pulp until it is dilute enough to be transferred by means of a stuff pump to a regulating box, the function of which is to provide a regular supply of pulp to the machine; thence the pulp is carried to the screen or strainer. On leaving the strainer the pulp passes into a vat in which there is an agitator to keep it well mixed in suspension with the water. There are numerous modifications of the beating engine, designed with a view to economy of space, the more rapid and even treatment of the material, etc.

From the vat into which the pulp discharges after it has passed the screens or strainers it flows down over an apron to the endless wire cloth of the Fourdrinier machine. This wire cloth is generally from 32 to 40 ft. long, its width being variable and based upon the greatest width of the sheet of paper which it is intended to make. The wire cloth is made of fine brass wire, the meshes varying from sixty threads upward to the inch. The wire cloth is supported on a series of brass rolls of small diameter placed near together. By this means uniformity in the layer of the pulp on the wire is gained, if the stuff in the vat is maintained of even consistency. These "tube rolls" are supported in an iron frame to which a violent lateral motion is given. This causes the fibers to interlace in various directions, and thus form a sheet which shall be nearly, if not quite, as strong in one direction of its texture as another. The water drains from the pulp through the wire cloth, and is received in a shallow box or trough. The frame in addition to the tube rolls carries several other rolls. On top of the frame at the point where the pulp flows on the machine, and extending lengthwise of it for about two thirds of the length of the wire, there is a "deckle frame" supporting two endless rubber straps, each about 1 in. thick, and running over pulleys, one on each side of the machine. These rest upon the wire cloth, and, preventing the pulp from spreading or flowing over its edges, regulate the width of the paper. By the time the pulp has passed the deckles the sheet is

PAPER

formed, although yet in a very moist and weak condition. Next and near to the deckles is located the " dandy roll," a cylindrical framework of brass covered with fine wire cloth, which presses on the surface of the wet layer of pulp, and aids in expressing the moisture; it also impresses what is known as the "watermark upon the paper. This impression is given by means of designs made from wire and soldered to the exterior covering of the roll. If the paper is not intended to receive any special design, but is to be alike on both sides, no device is fixed to the interior of the dandy roll, and the impressions made by the

FIG. 2.-BEATING ENGINE.

latter upon the moist pulp are the same as those received from the machine wire on its

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under surface. In this case the paper produced is known as "wove." "Laid" paper is that which has parallel lines watermarked at equidistant intervals, the marking being done by a series of wires encircling the exterior of the dandy roll. For the purpose of extracting a further amount of moisture from the pulp layer before it leaves the wire, there are two or more suction boxes having open or perforated tops.

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At this stage the paper has acquired sufficient consistency to pass without breaking to the couch rolls, two in number, the lower one carrying the wire cloth and giving it motion. From the couch rolls the web is conveyed on an endless woolen felt between the two "first-press rolls." The paper is then carried to the "second press," where it is transferred to another endless felt, which in turn conveys it farther on its way to the "dryers." The dryers" are metal cylinders of large diameter heated by steam. These drying cylinders vary in number on different machines, and are ranged one after the other, or in two tiers, one row above the other. Having passed the dryers, the web is passed between a series of polished rolls, or "calenders," mounted one above the other in a frame, to form a "stack," their purpose being to give the paper a smooth surface. Leaving the calenders, the web is wound on reels, and thence it goes to the cutter, where it is divided into sheets. Where the paper is intended for use on a web printing press, it is always supplied in rolls. Should it be desired to give the paper a higher finish than it has so far received, it is taken to the finishing room, where it is subjected to the action of super

PAPER

calenders having rolls made from disks of paper or cotton batting, mounted on steel shafts, and so solidly compressed by hydraulic pressure that they can be turned off truly cylindrical in a lathe. These rolls alternate with chilled-iron rolls in a frame. Another method of surfacing is to pass the sheets of paper between highly polished metal plates, through two heavy rolls which give a powerful pressure. So treated the paper is said to be "plated."

The method of sizing in the engine has been outlined. The sizing is done for the purpose of removing the porous and absorbent character of the paper, so that it can be written on. Further sizing is given on the machine, a weak solution of gelatin or animal size being placed in a shallow box through which the paper passes midway of the dryers, going thence between two " squeeze rolls," which remove the superfluous size; this is known as "tub sizing' 66 as well as machine sizing."

The Cylinder Machine.-An English paper maker named Dickinson is credited with the invention of the cylinder paper-making machine in 1809. This machine is of an entirely different type from the Fourdrinier. It consists of a large and square vat, in which is mounted a framework of brass covered with coarse wire cloth, over which an outer covering of fine wire is smoothly fitted. This cylinder is of large diameter, and fits closely by means of interposed packing to the sides of the vat in which it rotates. As the cylinder rotates it takes up on its surface a thin film of pulp, which, as it encounters atmospheric pressure, is drained of some of its water through the wire covering of the mold, the water passing out through the end of the cylinder and through the side of the vat. At the top of the vat, and connected therewith, is a framework carrying a couch roll, which rests upon the face of the making cylinder, and rotates with the latter. An endless felt runs over the surface of the couch roll, and passes to and between the first press rolls, which are located in a stand next to the vat. As the thin film of pulp forms on the cylinder mold it is brought up and in contact with the felt passing over the couch roll, and, being taken up by the felt, is carried continuously onward to the first press, where it loses a further proportion of moisture, thence to the second press, as on the Fourdrinier machine, and then to the dryers and calenders. less waste of pulp on the cylinder machine, but as there is no "shake to give lateral motion to the fibers, the latter lie mostly in the line of travel of the web, the paper thus made being weaker across the grain than lengthwise. A double- or triple-cylinder machine consists in the combination of two or three vats and making cylinders, such a combination sometimes including twelve vats and cylinders. In such machines as many webs of paper as there are cylinder molds are formed and brought in contact prior to going through the press rolls, where they are pressed together. Thus it is possible to make sheets of varying degrees of thickness. The inner layers may be made of cheaper stock, while

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There is

PAPER

the exterior surfaces may be of a better grade of material and colored as fancy may direct.

Wet Machine.-This is the first part of a single-cylinder machine, having first-press rolls, and is arranged to wind the sheet of paper in continuous layers upon the upper press roll until the desired thickness of material has accumulated upon the roll. When this has been attained an alarm bell rings, and the attendant then operates a hand lever which moves a knife down and on to the roll, by this means cutting open the paper cylinder formed on the roll and releasing the sheet. The wet machine is used for making binders'

FIG. 3.-STANDARD WEB MACHINE.

board, wood-pulp board, leather board, etc., and sometimes for strawboard.

Esparto grass, otherwise known as alfa and Spanish grass, is used to a great extent in Europe. The fiber after bleaching is white, soft, and of excellent quality. A similar boiling process is employed for the production of pulp from ordinary straw. The alkali in the residuum is recovered by evaporation, in special apparatus, to the extent of about eighty per cent. One of the most important papermaking materials is derived from wood. There is a distinction between wood pulp and wood fiber. The first is obtained by mechanical means and the second by chemical treatment. Wood pulp is produced by grinding. Wood pulp has been the great cheapening agent in what are known as print papers. While paper can be made entirely from wood pulp, or mechanical pulp, as it is sometimes called, the fiber is too weak to make a sheet of paper of sufficient strength for most of the ordinary purposes of daily use, and for this reason it is mixed in varying proportions with other material, wood (chemical) fiber being the chief admixture. Wood fiber is commonly known as chemical fiber. It is produced by two methods-the alkali and the acid processes. In the alkali or soda process the encrustating matter of wood is easily operated upon by dilute alkali, the power of which is increased at a higher and increasing temperature. The alkali has a solvent and saponifying effect. Poplar is the wood generally employed in the soda process, although other woods can be and are utilized, including pine, spruce, and hemlock. The wood is denuded of its bark and cut into chips, which, after being dusted, are put into large boilers commonly known as digesters, which are heated by coils supplied

PAPER

with steam through the journals and rotating with the boiler. The chipped wood having been packed in the digester, a solution of caustic soda is added to it. A steam pressure of about 90 to 100 lb. from eight to ten hours is requisite to cook the wood. The resultant fiber, when washed and bleached, is almost entirely pure cellulose, soft and of a fair degree of strength. The sulphate process is a modification of the soda process. In this the carbonate of soda is substituted to a large degree by the sulphate of soda.

The acid or bisulphite process consists in boiling the previously prepared wood in a solution of bisulphite of lime. Other bisulphites, such as bisulphite of magnesium or sodium, may be used, notably the former, which is employed in the Ekman process. The wood is first prepared with great care, the bark and knots being removed, and also all decayed and stained pieces; it is then cut into chips or into disks about 1 in. thick, after which it is packed in the digester. The sulphite liquor is then run in quickly, the digester is closed, and steam pressure is gradually turned on. The strength of the liquor is generally about 10° temperature, carrying about 3 per cent of sulphurous acid. The corrosive action of the bisulphite liquor

is such that it is necessary to line the digesters with acid-resisting coatings. The woods chiefly utilized are spruce and Swedish fir and pine.

Paper is classified under various heads in different countries, and its subdivisions are known by varying names. Its chief divisions are printings, writings, wrappings, and boards. These include nearly all of the grades. Each class has numerous subdivisions.

Although sheets of paper vary in size, when folded to make up in book form they have other designations, according to the number of leaves into which a sheet is subdivided. Thus a sheet of paper when folded is described as follows:

There are several kinds which call for special description. Some of these are used in the form in which they come from the mill, while others are subjected to treatment in various ways at the hands of manufacturers, broadly known as converters, who prepare the product for special uses. Blotting paper is unsized and used for absorbing ink and fluids. Cigarette paper is a thin tissue from which all chemicals have been removed or neutralized, used with tobacco for making cigarettes. Coated paper is a print paper to which a coating of white material, sometimes china clay, or gypsum, sulphate of barytes, etc., is applied; chiefly used for books or for fine prints from woodcuts and process blocks. Copying

PAPER HANGINGS

paper is a thin tissue made specially for taking copies of letters, bills of lading, etc. Detail paper is a special grade of heavy Manila paper for the use of artists and draftsmen, its surface being such as to submit to erasures without destroying the texture of the paper. Enameled paper is a glazed paper to the surface of which a metallic pigment has been applied and polished. Filter paper is unsized, thick, and spongy; employed for filtering solutions in pharmaceutical or laboratory practice. India paper is used for taking those impressions from fine engravings on steel or copper known as India proofs; also for proofs of the finest woodcuts and photo-mechanical plates; is made from the inner fiber of the bamboo. Oxford India paper is the thinnest of opaque papers, so thin indeed that five original octavo volumes of the Bible, containing 2,688 pages, have been printed on it and included in the space of one volume. Ivory paper is bristol board coated with animal size, with an admixture of white pigment, and then polished. Japan paper, prized by artists, etchers, and plate printers, is made from the fiber of the paper mulberry in various thicknesses; is of strong texture and creamy color.

U. S. fiber paper is a specialty adopted by the U. S. Govt. for use in its treasury notes and other certificates of indebtedness; is a bank-note paper containing fibers of colored silk, which are added to the pulp as it is made into paper. Manifold paper is a thin tissue used for writing on with a stylus, which produces a number of copies on as many sheets between which strips of carbon paper are interposed. Parchment paper is made by passing unsized paper through a bath of dilute sulphuric acid. Safety paper is chemically or mechanically prepared so that tampering with any printing or writing on it may be detected. Watermarks of a special design are sometimes employed, as in the Bank of England notes, or silk threads are embodied in the fiber, as in U. S. fiber paper. Silver tissue is a fine thin paper used for wrapping silverware. Sponge paper is made from paper pulp containing pieces of sponge in a state of fine subdivision; used in surgery. Toned paper or tinted paper is tinted or has its whiteness subdued or modified by a very slight addition of color to the pulp. Tracing paper is thin paper which has been treated with oil or a thin solution of resin to make it transparent; used by artists and draftsmen. Carbon paper is a thin tissue, saturated with a pigment carried in oil, and capable of imparting color to sheets of paper with which it may be brought in contact. Lithographic transfer paper is prepared by coating paper with starch paste, and is used for transferring designs from one lithographic stone to another. Photographic paper is coated or impregnated with various chemical constituents sensitive to light; occurs under many different names.

Paper Hang'ings, or Wall Paper, ornamental papers intended to be pasted on the walls or ceilings of apartments. Paper hangings are reported to have been made in Spain and Holland before 1555, but their manufacture has

PAPIN

only in recent times become a leading industry. The choicest wall papers are of good material, but for the low grade woolen, hempen, and jute waste are used. The paper was formerly all printed by hand, either by the process of block printing or stencil. Cylinder printing is now used, identical in principle with the processes employed in calico printing; but choice styles are still hand printed, the blocks being either engraved wholly in wood or partly made up with metal for the thinner lines. Flock printing is done by printing the pattern in with varnish and then sprinkling on colored flocks, in powder, the flocks being the shearings of woolen cloth. Such papers are generally called velvet paper. Satin papers are finished with powdered statite and polished. Paper Nau'tilus. See ARGONAUT.

Paphlago'nia, in ancient times a district of Asia Minor, extending along the S. shore of the Euxine from Pontus to Bithynia, and bounded S. by Galatia; inhabited by wild and warlike tribes belonging to the Semitic race; celebrated for the excellent horses it produced; originally formed an independent state, but was conquered by Croesus, and later merged in the Persian Empire. After the death of Alexander it became independent once more, but was conquered by Mithridates, and after his fall it was made a part of the Roman province of Galatia.

Pa'phos, name of two ancient cities of Cyprus; one, the present Kukla, was often called Palaipaphos (Old Paphos), and was famous for its Temple of Aphrodite, who was said to have been born here from the foam of the waves; the other, the present Baffa, was called Neopaphos (New Paphos), and was the place where St. Paul preached to Sergius.

Papier-maché (pă-pya' mä-sha'), pulp of paper mixed with glue or gum arabic, molded, and dried, or paper pasted in sheets on models. The cheaper articles of papier-maché are made of white or brown paper mashed in water and pressed in oiled molds. The better articles are produced by pasting or gluing together sheets of paper, which, when a proper thickness is attained, are powerfully pressed and dried. While moist the preparation may be molded into any form, and when dry it may be planed and rasped to shape. Several coats of varnish are next applied, and the inequalities are rubbed down with pumice stone. It is ornamented with gold, bronze powder, or colors, after which a varnish of shellac is applied and dried.

Papin (pä-păñ'), Denis, 1647-1712; French physicist; b. Blois; practiced for some time as a physician, but devoted himself later to physics and mathematics under Huyghens; made, 1687, Prof. of Mathematics at Marburg; writings are numerous, but scattered; contain many valuable discoveries, most of which, however, were not fully recognized during his lifetime; was the inventor of Papin's digester, a contrivance for softening bones; 1707 tried on the Fulda River a vessel propelled by paddles operated by a steam engine; improved the pneumatic machine invented by Otto von Gue