Paper—Watermarks—Quiring.

Although we get our word “paper” from “papyrus,” this latter was not a paper at all. The essential characteristic of a true paper is the matting or felting together of small fibres, whether these be of wood, linen, or other substance. Papyrus was the inner bark of a beautiful reed, which grows along the banks of the Nile, and from a very remote period strips of this bark were laid over each other at right angles, fixed together with gum, or perhaps a little Nile mud, and used for writing upon with a soft pen. The right-angular lines of the two layers of papyrus bark can easily be seen on any papyrus MS.

Papyrus is not a good substance for writing upon; it is at first too soft, and then it gets brittle and is apt to crumble away. By sticking successive strips of papyrus to each other ancient scribes produced long rolls of manuscript, and from these rolls we derive many of the book terms which are still in use. The most obvious is “volume,” which is from “volvere,” “to roll up”; and “Bible” comes from the Greek “????,” meaning the inner bark of papyrus.

In China the possibility of making thin feltings with silk fibre was probably known at a very remote period, and it is likely enough that from some such unsatisfactory production the better and usable kinds made of vegetable fibres evolved itself. We cannot now say when the possibility of felting together fibres of wood or grass first became known to the Chinese, but it was certainly well understood in the fifth or sixth centuries, because specimens of it still exist.

In the middle of the eighth century, in 751 A.D., there were certain tribal disturbances on the Chinese frontier of Persia, and one of the combatants called in the help of the Chinese. These, however, suffered defeat at the hands of the Arab governor of Samarkand, who brought back some Chinese prisoners to his town. These men were acquainted with the Chinese methods of making paper.

From these Chinese prisoners the Arabs and their friends the Persians learnt the art of paper-making with vegetable fibres, but the supply in this particular very soon gave out, and because enough suitable fibres were difficult to get they mixed them with pulped rags. Eventually the Samarkand paper-makers used rags only, and these they easily got in sufficient quantities from old linen clothes, and also the mummy wrappings from Egypt were made use of in the same way.

From the Arabs the knowledge of paper-making passed rapidly to Europe, and by the middle of the tenth century it had entirely superseded the use of papyrus.

The researches of Dr. J. Wiesner and Dr. J. Karabacek, both professors of the University of Vienna, have been of incalculable value as regards the composition and history of ancient paper, and they were fortunate enough to have the opportunity of examining the papers in the collection of the Archduke Rainer, among which are specimens of very early work. The professors have examined these and other old papers microscopically and chemically, and found that from the beginning it was considered necessary to load papers with some binding or filling substance; they found starch, starch flour, probably from rice, and among the Chinese papers a dressing of powdered gypsum. Without some such dressing the papers would have resembled our blotting paper, and it would have been almost impossible to write upon them.

Professor Wiesner found that Chinese papers of the eighth century were really mixed papers; they contained fibres of mulberry bark, hemp and rags. Rags of fishing nets themselves would contain fibres of flax, hemp, and China grass. But the main constituent of ancient Chinese paper is fibre of mulberry-bark, and I believe it is so still, although China grass fibre is also much used.

Specimens of Chinese papers from the eighth century onwards can be seen at the British Museum. They are soft, but have lasted fairly well, and do not appear to show any wire marks. The colour of these papers is much the same as Chinese papers made now, but in some instances they have certainly darkened as modern wood pulp papers also do.

One of the later specimens, a bank note issued during the reign of the Emperor Hung-wu, A.D. 1368-1399, is made of a darkened pulp, probably due to admixture with a little lamp black, and on it are lighter impressions from large stamps bearing the square seal letters. It is just possible that these marks may be of the nature of watermarks, and were impressed while the pulp was soft and wet, but it is not possible now to take the bank note up from the cardboard on which it has been pasted, as to do so would probably cause it to fall to pieces, so it cannot, for the moment, be properly examined.

Corean and Japanese papers were the same as Chinese, and they all look as if there are no wire marks or watermarks upon them, with the one exception I have mentioned, but Dr. Wiesner says that by the ninth century marks show in many instances which prove that papers were made in moulds or sieves with network bottoms, the impression of which remains like our “chains” or laid marks. In the King’s Library at the British Museum is shown a piece of Oriental paper, an official letter in Coptic, dated A.D. 1048. It does not look so strong or good as the Chinese paper, but resembles thin blotting paper, and shows no wire mark.

An early example of European paper is preserved in the Record Office in London. It is a letter from the Count of Toulouse to Henry III., and is dated A.D. 1216. In France, however, by this time, the making of paper had been understood for some time, as it was made there in 1189. In Belgium it was not made until 1551, in which year a paper mill was set up at Tourneppe by Henri de Nevere.

By the end of the fifteenth century paper-making in Europe was perfectly understood, and the papers of that date, and for some time after it, are frequently excellent in every way, and as sound, strong, and good now as they were when first made.

The first English book printed on English paper is Bartholomaeus, De Proprietatibus Rerum, published 1495-6. The paper is of high quality, it shows a fine wire mark, and a watermark of a double circle enclosing an eight-pointed star. The paper was made at Hertford by John Tate, who was afterwards Lord Mayor of London; the title page is cut in wood, and the book is illustrated with outline wood-cuts.

At the end are some verses, and among these occur the lines:—

It is paper to be proud of, and John Tate the younger would unquestionably look upon the large majority of our modern papers with the utmost scorn, and he would be perfectly justified in doing so.

The early method of making paper was to allow the pulp to settle at the bottom of a trough like a sieve, with a wire bottom, in which the wires were arranged in a certain way, thick and thin, the trade mark of the maker also being outlined in wire. The faint marks these wires cause in the paper are called watermarks, and although at first they were makers’ marks, they eventually denoted the size of the sheet of paper on which they were shown.

The present method of making paper from rags is to pulp them thoroughly in water, and let the white particles become so thoroughly diffused that the liquid in which they float looks like thin milk.

This thin mixture, however, if left quiet, very quickly resolves itself into a sediment of white fibres with clear water above them. If now the superambient water can be drawn off, and the sediment pressed flat, paper is the result. But it is not so easily done as said. In order to catch the sediment in the most satisfactory way, the milky fluid containing the rag fibres is allowed to flow in a thin stream over a long, shallow trough, which is kept moving onwards and is also so arranged that it has a sideways tremble, backwards and forwards as well. The effect of this is that when the further end of the trough is reached, on its floor there is a thin continuous film of slightly matted fibres, the water from which has flowed away along the sides of the trough. Now another device comes into play; a thin light roller of wire presses lightly on the wet film, and by this pressure the little fibres are pressed upon each other so that they mat, interlace, and cohere together. The paper in this state is of course very delicate, but by reason of a quick drying and carrying off on light rollers it soon acquires the strength necessary to enable it to hold together until it is quite dry. Then it goes through several other stages, the most important of which is pressing. The various processes can obviously be modified easily enough so as to make a thin paper or a thick one. Paper made in this way with a vibratory trough is called “machine made,” and by reason of its fibres laying more or less in a uniform direction the resulting paper is more easily torn in one direction than in the other. If a circular piece be cut out of such pulp and laid on water it will tend to fold up two of its opposite sides.

But ancient paper was made in a trough held by hands and given a lateral movement, then pressed and dried in some simple way. By such a procedure the fibres are thoroughly mixed, and do not lie in one direction more than in another, so that if a circular bit of such paper be laid in water it will turn upwards at the edge evenly all round, and look like a little saucer.

I have mentioned a light wire roller which presses the wet film more or less into shape just before it leaves the long trough to be dried. As long ago as the thirteenth century in Europe the fact that devices could be impressed upon the undried film by thinning it and making it more transparent where touched appears to have been known, and from about that time onwards “watermarks” have fortunately been applied in the same manner, namely, so as to come in the middle of the first leaf of the pair forming a folio. It is also fortunate that the “chains” or wires forming the rollers have always been laid in the same way; it is certainly the obvious one, but obvious ways are not always adopted. The result is that by observing the direction of the strong chain marks and the fine “laid” marks between them much information concerning the folding of the original sheets can be obtained.

In very early papers these rules cannot be safely followed, because early chain marks as well as early watermarks were not produced in the same reliable way. The paper being made in moulds with wire netting at the bottom, the impression came below the paper instead of above it as in the case of the roller, and also the sizes of the sheets were more likely to differ.

Watermarks are the semi-transparent devices which show on certain pages of a printed book. They are to be seen on most papers of the fourteenth to the eighteenth centuries, and there has been a good deal written about them, especially abroad. The devices were outlined in wire and set in the bottom of the trough or on the wire roller I have just described, so that the lines are impressed upon the pulp just when it is in its most sensitive condition. The pressure from the wire device thins the pulp wherever it is touched, and so when dry the device shows lighter than the rest of the paper.

These marks should be called wire marks rather than watermarks, and the French word for them, “Filigranes,” is more correct than ours. The difference in tint between a watermark and the rest of the paper is so distinct that a photographic negative placed under one will render a capital photograph of it, far better than any drawing, but it needs a long exposure.

Watermarks are already of considerable value to Bibliographers, and it is likely that in the near future they will be much more noticed, especially in English books. Many frauds have already been detected by reason of the watermarks, as it is a point that faussaires have so far paid little attention to. The marks are, however, not to be relied on after about 1750, as they do not run reliably in machine made or wove papers.

Armorial devices have been largely used as watermarks. Many of the earlier marks show the arms of towns, especially continental ones, and among others there are the arms of France, Portugal, William and Mary and Queen Anne, shown in full heraldic outlines.

The Holbein family of Ravensburg bore a bull’s head as their armorial badge, and they were paper makers, so the bull’s head shows on their paper as a watermark. It was afterwards much copied, and during the fifteenth and sixteenth centuries it became a favourite mark on German papers. There does not seem to have been any strict copyright in any of the devices used as watermarks. They were freely used by any one who cared to do so, but the copies were never very carefully made, they were always variants of the original. They were moreover generally accompanied by another mark, that of the maker, on another part of the paper. The same privilege of using a “maker’s” mark was also allowed to the silversmiths in addition to the official hall mark.

To some slight extent watermarks on paper made for particular books have followed the subjects of those books, and in accordance with a loyal feeling there are instances of a crown watermark being used on paper prepared for special copies of books intended for presentation to reigning sovereigns.

On papers used for early English printed books we find the favourite German bull’s head, bunches of grapes, unicorns, dogs, hands with stars, and shears. These appear in several sizes, and show many varieties and modifications of their original designs.

In the sixteenth and seventeenth centuries a greater variety occur; on English paper there is found the post horn and the fool’s cap, sometimes showing as a cap only and sometimes as a fool’s head with cap and bells. A similar design was largely used abroad. In the time of Charles I. a crown was a usual watermark on official folio paper, but the Rump Parliament ordered that the foolscap should be in future substituted for it, which was done. “Double foolscap” is still used as a designation for a certain size of printing paper, so also is “double-crown.”

The foolscap itself shortly gave way to a figure of Britannia or a lion rampant. The post horn was another common watermark here; it gave its name to its paper about 1670, when the mail carrier was accustomed to announce his approach by a blast from his horn. The name “Post” still designates a certain size of printing paper. The smallest folio paper of the seventeenth century was marked with a watermark of a “pot,” and hence the name.

For specially printed books it is a pretty fancy to have a coat-of-arms set as a watermark, and it is now and then done, but I fear few readers notice it. Many papers are now made without watermarks, and it is likely enough that, except for trade terminology, they will gradually die out altogether as being unnecessary.

The possibilities of artistic watermarking have not yet been fully realised. At the St. Louis Exhibition in 1904 there was a German exhibit which showed the remarkable effect which could be made by impressing paper pulp by means of a photographic plate in relief.

The papers which had been so treated were set up in a frame with a light behind them, and they looked like most delicate paintings in monotone. Those exhibited were portraits of celebrities, and they were not only excellent but possessed the quality of permanence in a remarkable degree.

Printing papers are generally white, but sometimes they have been used in colour, green, pink, blue or yellow. Such papers are now and then found in Italian, German, and English books, more rarely in French. Silk and satin have both been used for printing on in England from the seventeenth to the nineteenth century. Vellum has also been largely used for special copies of fine printed books.

A recent French book of prayers is entirely woven in white and black silk. It looks like a beautifully printed book with monotone borders.

An original sheet of paper can of course be made and cut to any size, and the terms folio, quarto, octavo, and duodecimo do not indicate any actual size except in bookbinders’ specifications. The terms only indicate the number of times the original sheet has been folded, and this obviously is a matter which is subject to as much variation as the printers choose. But fortunately such foldings do not vary much, and so we may safely mention those that are most commonly used. There are several ways of finding this out, the most obvious being to count the leaves which follow any one letter in the white line at the bottom of the leaf. This letter is called the “signature.” If there is an A or A 1 at the bottom of the first leaf, and when eight leaves have been turned over a B or B 1 appears, then the book is an octavo, and so on. Another way of determining the same thing is by means of the direction taken by the chain or wire marks all over the paper, and yet another is to be found by studying the position of the watermark. But neither of these tests are conclusive, and often enough there are neither chain marks nor watermarks to be found at all, and the sheets are not always rightly or carefully cut, which brings the watermark all wrong, so the following notes are only what may be expected in normal books.

If a piece of paper or page of a book printed before 1750, and possibly in later work, be held up to the light, certain lines may be seen all over it in a lighter tint than the rest of the page. These appear as long thick lines crossed at right angles by short thin ones. The long thicker lines are known as “chain” lines, and the shorter ones “laid” lines, and they are of some value when they exist for helping to determine the “size” of the book.

—Fol. If the original sheet is folded once it is called a folio, and in this case the chain marks are perpendicular and the watermark is in the middle of the first leaf. In a folio there is one fold, two leaves or four pages, and nothing to cut. Most of Caxton’s books are folios although they are quite small.

—4^o in size. If the once folded sheet be folded again across the other way we get a gathering with four leaves, or eight pages, called a quarto. The chain lines are horizontal, and the watermark in the middle of the back of pp. 4 and 5; there are two foldings and two tops of leaves to be cut.

—8^o. If the quarto be again folded we get a gathering of eight leaves, or 16 pp., called an octavo, which is the commonest size for English books. In an octavo there are three foldings, the chain lines are perpendicular, the watermark is quartered at the tops of pp. 3, 4, 11 and 12, and there are two tops and two fronts to be cut.

The further foldings of 16^o, 32^o, and 64^o are the same operations carried further, but although such sizes do exist they are so uncommon that a further description of them is not necessary.

—12^o. In the case of a duodecimo a different initial folding is followed. The original sheet instead of being folded once across the middle, as in the case of a folio, is now folded into three equal divisions. The parallelogram thus formed is folded across its shorter diameter, and this again along its longer diameter. There is now a gathering of twelve leaves, or 24 pp., with four foldings, the chain marks perpendicular, the watermark halved at the tops of pp. 3 and 9, and there are two tops and four fronts to be cut. It is the commonest size of the smaller French books.

As to sizes, folios run from the great Atlas of Charles II., measuring five feet nine inches and a half by three feet two inches and a half, and requiring eight skins of morocco for its binding, to the tiny Galileo a Madame Cristina de Lorena, 1615, “imprimÉ en 1897,” measuring one half by one quarter of an inch. A folio cannot be recognised by its shape.

The sizes of quartos and octavos are also very varied, but, roughly speaking, they can be recognised by their shapes, especially in the case of modern books. A quarto is generally squarish in outline, nearly as broad as it is long; an octavo is an elongated rectangle, its breadth considerably less than its length. A duodecimo is always much longer than its breadth.

As curiosities, books have been made in many forms, circular, heart-shaped, octagonal, flower or animal forms, but they are of small importance, and have been chiefly made as Christmas cards, valentines, and such ephemeral publications.

The rules as to quiring of books printed on paper do not apply to books printed on vellum. Such books are always folios, and they are generally quired in gatherings of ten leaves, following the fashion used in the ancient manuscripts, but, of course, they can equally well be gathered together in any even number that may be preferred. There is no rule.

In Europe, until the nineteenth century, paper was always made from triturated rags, but the demand for cheap literature which has become so urgent in recent years has compelled paper manufacturers to find some commoner material from which to make their paper.

It is possible that the way out of the difficulty was suggested by an analysis of Japanese paper. This has been known here for some time. It is strong, soft, and valuable for many reasons, and is cheaply made of fibres from plants of the mulberry tree species. Japanese paper is hand made and has a certain amount of dressing, its surface is dull, but takes impressions from engraved plates or type easily. It appears to last fairly well, but would probably not stand much wear at the joints.

The idea of using pulped vegetable matter for paper was, however, not new, even to the Japanese, as there was such a thing as paper made from papyrus, but it does not seem to have been much employed, because it was not necessary in view of the fact that the papyrus did quite well by itself without any further manipulation.

For reliable papers, the Committee on the Deterioration of Paper appointed by the Society of Arts in 1898 give in their report a statement that 70 per cent. should consist of fibres of cotton, flax, or hemp, but about the middle of the nineteenth century it was found that passable paper could be very cheaply made from straw and from esparto grass, and this paved the way for the disastrous use of mechanical wood pulp for cheap newspapers and books.

Many sorts of wood pulps are now made for this purpose, and there is no doubt that the industry of breaking up wood for the purpose of paper making is a large and increasing one. In Norway there are several large establishments already working at this output. The fibres of spruce, pine, birch, poplar, jute, and manilla are all extensively used. The wood is cut up into small pieces and triturated until it is in a state of fine dissemination, a mass of small fibres, in which condition it is mixed in certain proportions with the other materials of which the paper is to be composed. In spite of the warnings of the Society of Arts Committee, there is no doubt that the use of “mechanical” wood pulp for paper is increasing, and this regardless of the fact that there is no lasting quality in such material, for the fibres of the wood are invariably brittle, and they also darken rapidly under the influence of light.

The dressing of such papers with resin or gelatine effects a certain improvement; gelatine particularly adds to the life of a paper and increases the elasticity of the wood fibres, but this good effect tends to die out in time. Resin is of less use.

One particularly troublesome result of having to deal with wood pulp papers is that it will not hold the threads used in ordinary binding; the thread cuts right through the paper because of the shortness or brittleness of the fibres, and if a book printed on such paper has to be bound, the only safe way to do it is to frame each page in a border of sound rag paper, and then have it sewn as usual. Wood paper will not stand bending, but breaks off short if there is anything like a joint or fold in it, and the framing or mounting prevents this. The process of mounting every leaf of a book is, however, a very expensive one; a couple of pounds may well be spent on a comparatively small book for this operation alone, so that the prospect before owners of libraries who wish to keep their books in good order is not brilliant. No amount of dressing can make such paper really strong, as it is the fibres themselves that are in fault.

But there is another form in which the use of wood is not so harmful, and in this case the fibres are no longer there to be found fault with. “Chemical” wood pulp is a form of cellulose, and it is likely that it is destined to play an important part in the paper of the future, in conjunction with fibres of various sorts.

Chemical wood pulp is prepared from the wood fibres by “digesting” with caustic soda or bisulphide of lime, as reducing agents. The process is one of much interest, and moreover a good deal of wood has to be used to make a comparatively small amount of wood cellulose. Esparto and straw celluloses are not so good as wood cellulose.

The invention of the “half-tone” process, by which a dotted block can be produced from a toned drawing, print, or photograph, can be made, is responsible for much dangerous procedure with regard to the paper upon which the prints from the dotted blocks are to be made.

In itself the invention of the half-tone process is a wonderful and beautiful one, but it has done more to ruin the already decadent modern paper than anything else, because it has made the dressing of the paper of greater importance than the paper itself.

Incidentally, the half-tone block has given the death-blow to the old and beautiful art of wood engraving, which is now only found in quite exceptional instances. But the half-tone block has, nevertheless, provided some small solace for the dispossessed wood engravers, because the soft metal blocks go wrong in light places and themselves need careful revision with a graver. This touching-up is so general, and so much technical skill is required for its proper execution, that it has already become a recognised profession, and the engraver’s name is often enough recognised in the lettering of the prints made from such blocks, especially in American publications.

The dots of half-tone blocks were at first of an easily visible size, but as the method of production became better understood it was found that they could be made so small that they were no longer visible as separate dots to the unaided vision, but that the effect produced was really that of a tone-wash.

But the very finely grained blocks were difficult to print from, the ink stuck too readily between the dots, where it was not wanted, and the surface of the paper was not even enough to give a clear impression, even if it was calendered and super-calendered. So something had to be done to give the paper a more level surface, and the needed material was found in china clay mixed more or less with barytes. It is laid down in the Society of Arts Report that the amount of this dressing should in no case exceed 10 per cent. in any paper, but modern “art” papers have for a long time much exceeded this fair proportion.

From the beginning some kind of dressing has always been found necessary in the manufacture of paper, but nothing so dangerous as china clay has ever been used. The net result is that almost all modern editions-de-luxe, and fine illustrated books generally, either having half-tone plates or colour plates done by the three colour process, consist of little else but thin sheets of china clay supported by the smallest possible skeleton of wood or other cheap fibres.

It must be at once granted that the impressions from delicate half-tone blocks made on clay paper are admirable, and it is also true that the printing ink makes the clay insoluble in water wherever it touches it. But the clay has a certain affinity for damp, and books printed on clay paper very readily show damp stains, and if left for any time in a really damp place they are liable to become solid bricks of white mud, quite impossible to repair.

If very dry the non-cohesive clay will turn to a white powder. Moreover, this clay-laden paper will not hold binding threads, so again it has to be preserved. A book printed on such material has to be treated in the same way as I have described in the case of wood pulp paper.

There is, however, a plan of preserving prints on clay, and this is to fasten down the printed portion on a piece of sound paper from the beginning. This is already done to some extent, and it should be universal in the case of isolated plates, but when a book is all printed on clay paper, as many fine and valuable books unfortunately are, it is difficult to say what is best to be done. The only real remedy seems to be a refusal on the part of purchasers to buy such books. But purchasers do not always know when they are buying clay instead of paper. It is, however, not difficult to tell, as the clay-laden paper feels very smooth and soft to the touch of a dry finger. This peculiarity can be easily detected in one or other of the American magazines, Harper’s or Scribner’s, and the difference between the feel of a page holding an impression from a fine half-tone block, and that having only text, will at once be evident.

If a mark may be made on a suspected sheet, a drop of water should be put upon one corner, left a second or two, and then dried off with blotting-paper. Now a light scrape with a knife over the damped place will remove a layer of white clay if it is there.

There is no doubt that the large majority of our modern books will not be in readable condition in about a hundred years’ time from the date of their publishing.

BOOKS TO CONSULT.

Paper.

Arts, Society of.—Report on the Deterioration of Paper. London, 1898.

Blades, W.—(AthenÆum, March 30th, 1889, p. 409. Paper on Watermarks).

Blanchet, A.—Essai sur l’histoire des Papier. Paris, 1890.

Breitkopf.—Versuch die Einfuhrung des Leinenpapieres. Leipzig, 1784-1801.

Briquet, C. M.—La Legende PalÉographique du Papier de Coton. GenÈve, 1884.

Briquet, C. M.—Recherches sur les Papiers du x^e au XIV^e siÈcles. Paris, 1886.

Campredon, E.—Le Papier. Paris, 1901.

Charpentier, P.—Le Papier. 1890. (FrÉmy, E.)

Dunbar, J.—Notes on the Manufacture of Wood Pulp Papers. Leith, 1892.

Erfurt, J.—The Dyeing of Paper Pulp. London, 1901.

Evans, L.—Ancient Paper Making. London, 1896.

Girard, A.—Le Papier. Lille, 1892.

Goodchild, G. F., and Tweney, C. F.—A Technological and Scientific Dictionary. London.

Griffin, R. B., and Little, A. D.—The Chemistry of Paper Making. New York, 1894.

Herring, R.—Paper and Paper Making. London, 1855.

Hoernle, A. F. R.—Who was the inventor of Rag Paper? (Royal Asiatic Society Journal, October, 1903).

Hoyer, E.—Die fabrikation des Papiers, 1886. (Bolley, P. A.)

Karabacek, J.—Mittheilungen aus der Sammlung der Papyrus Erz. Rainer. Bd. II., III., 1887.

Kay, J.—Paper. London, 1893.

Klemm, P.—Handbuch der Papierkunde. Leipzig, 1904.

Lloyd, E.—Account of a sort of Paper made of Linum Asbestinum found in Wales. (Phil. Trans., Abr. III., p. 105, 1684).

Mierzinski, S.—Handbuch der Praktischen Papier Fabrikation. Wien, 1886.

Payen, A.—La fabrication du Papier. Paris, 1873.

Piot, G. J. C., and Pinchart, A.—Specimens des Papiers recueillis dans les diverses coll. de documents qui composent les archives gÉnÉrales du Royaume de Belgique. Bruxelles, 1872.

Sartori, L.—L’Industria della Carta. Milano, 1897.

Schaefer, J. C.—Attempts towards making Paper from Plants and Wood. (German.) Regensburg, 1765.

Stonhill, W. J.—Paper Pulp from Wood and other fibres. 1885. (Rattray, J.)

Valenta, E.—Das Papier. Halle, 1904.

Watt, A.—The Art of Paper Making. London, 1890.

Wiesner, J.—Mikroskopische untersuchung alter ostturkestanischer und anderer asiatischer Papiere. Wien, 1902.

Watermarks.

Briquet, C. M.—De la valeur des Filigranes du Papier comme Moyen de determiner l’age de documents. GenÈve, 1892.

Briquet, C. M.—Papiers et Filigranes des archives de GÊves 1154 À 1700. GenÈve, 1888.

Briquet, C. M.—Les Filigranes. Dict. Hist. des Marques du Papier. 4 vols. Paris, 1907.

Castan, A.—Catalogue des Incunables. BesanÇon, 1893.

Del Marmol, F.—Dictionnaire des Filigranes. Paris, 1900.

Denne, S.—Observations on Paper Marks, 1796. (ArchÆologia, XII., p. 114).

Heitz, P.—Les Filigranes avec la crosse de BÂle. Strasbourg, 1904.

Heitz, P.—Les Filigranes des Papiers contenus dans les archives de la ville de Strasbourg. Strasbourg, 1902-04.

Heitz, P.—Les Filigranes des Papiers de la BibliothÈque de Strasbourg. Strasbourg, 1903.

Lemon, R.—Collection of Water Marks. 1891.

Midoux, E., and Matton, A.—Etudes sur les Filigranes des Papiers employÉs en France au XIV^e et XV^e siÉcles. Paris, 1868.

Piot, G. J. C., and Pinchart, A.—Specimens des Papiers recueillis dans les diverses coll. des documents qui composent les archives gÉnÉrales du Royaume de Belgique. Bruxelles, 1872.

Serma Santander, C. A. de.—SupplÉment au Catalogue des livres de la BibliothÈque de M. C. de Serma Santander. Bruxelles, 1803.

Sotheby, S. L.—Principia Typographica (with examples of foreign watermarks). London, 1858.

Sotheby, S. L.—Typography of the fifteenth century (with examples of watermarks). London, 1845.