added to the pulp in the beating engine. _Yellow._--_Chrome Yellow_--The paper pulp is first impregnated with acetate of lead, and potassium or sodium bichromate added. This precipitates the chromate of lead as a yellow pigment. _Chrome Orange_--The addition of caustic alkali to the bichromate solution converts the chrome yellow into an orange. _Blue.--Prussian Blue_--The paper pulp impregnated with iron salts is treated with potassium ferrocyanide. The blue colour is at once obtained. _Brown.--Iron Buff_--A light yellow-brown colour due to the precipitation of ferrous sulphate by means of an alkali. _Bronze._--Manganese chloride followed by caustic soda. SOLUBLE COLOURS. (A) Natural Dyes. These colouring matters are now seldom used. _Yellow and Brown._--The vegetable extracts, such as fustic, quercitron, cutch, turmeric, have practically all been replaced by aniline colours. _Red._--Madder (Turkey red), Brazilwood, cochineal (a dye obtained from dried cochineal insects). Safflower. _Black_.--Logwood, used in conjunction with an iron salt. Cutch, used with an iron salt. (B) Coal Tar Dyes. The dyeing and colouring of paper pulp by means of the artificial organic substances has become a matter of daily routine, the expensive natural dyes and the ordinary pigments having been almost completely superseded. The numerous colouring matters available may be classified either by reference to their chemical constitution or simply on general lines, having regard to certain broad distinctions. If the latter classification is taken, then the dyes familiar to the paper-maker may be divided into-- (a) Acid dyes, so called because the full effect of the colouring matter is best obtained in a bath showing an acid reaction. (b) Basic dyes, so called because the colour is best developed in an alkaline solution, without any excess of mordant. (c) Substantive dyes, which do not require the use of a mordant, as the colour is fixed by the fibre without such reagents. Some of the most frequently used colouring matters are shown in the accompanying table on page 202. The distinction between _acid_ and _basic_ dye-stuffs is largely due to certain characteristics possessed by many of them. Thus magenta, which is the salt of the base known as Rosaniline, belonging to the basic colouring matters, a group of dyes which do not possess the fastness of colour peculiar to acid dyes, has a limited application. But by treatment with sulphuric acid magenta is converted into an acid magenta, and this dye has wider application than the basic salt. Similarly the basic dye called aniline blue is insoluble in water, and therefore has only a limited use, but by treatment with sulphuric acid it is converted into alkali blue, soluble blue and so on, which dissolve readily in water and are good fast colours. The acid dyes generally have a weaker colouring power than the basic dyes, but they produce very even shades. -------+-------------------+-----------------+----------------- Colour.| Acid. | Basic. | Substantive. -------+-------------------+-----------------+----------------- Yellow | Metanil yellow. | Auramine. | Cotton yellow. and | Paper yellow. | Chrysoidine. | Chrysophenine. Orange.| Orange II. | | | Naphthol yellow S.| | | Quinoline yellow. | | | | | Red. | Fast red A. | Rhodamine. | Congo red. | Cotton scarlet. | Paper scarlet. | Benzopurpurin. | Erythrine. | Safranine. | Oxamine red. | Ponceau. | Magenta. | | | | Blue | Water blue 1 N. | Methylene blue. | Azo blue. and | Fast blue. | Victoria blue. | Violet.| Acid violet. | New blue. | | | Indoine blue. | | | Methyl violet. | | | Crystal violet. | | | | Brown | Naphthylamine | Bismarck brown. | | brown. | Vesuvine. | | | | Black | Nigrosine. | Coal Black B. | | Brilliant black B.| | | | | Green | | Diamond green. | | | Malachite green.| -------+-------------------+-----------------+----------------- The difference in the composition of the basic and acid dyes is taken advantage of in the dyeing of paper pulp to secure a complete distribution of the colouring matter upon the pulp, with the result that the intensity of colour is increased, its fastness strengthened, and the process of dyeing generally rendered more economical. This is effected by the judicious addition of a suitable acid dye to the pulp already coloured with the basic dye. The direct colouring matters have but a very limited application for paper dyeing owing to their sensitiveness to acids and alkalies. In the colouring of paper pulp, attention is given to many important details, such as:-- _Fading of Colour._--Some loss of colour almost invariably occurs even with dyes generally looked upon as fast to light. The shade or tint of the paper is affected not only by exposure to light, but by contact of the coloured paper with common boards on which it is often pasted. The alkalinity of straw boards, for example, is frequently one source of serious alteration of colour, and the acidity of badly made pastes and adhesives another. In all such cases, the dyes must be carefully selected in order to obtain a coloured paper which will show a minimum alteration in tint by exposure to light or by contact with chemical substances. This is particularly necessary in coloured wrapping paper used for soap, tea, cotton yarn, and similar goods. _Unevenness of Colour._--The different affinity of the various paper-making fibres for dyes is apt to produce an uneven colour in the finished paper. This is very noticeable in mixtures of chemical wood pulp or cellulose and mechanical wood pulp. The ligno-cellulose of the latter has a great affinity for basic dyes, and if the required amount of dye is added to a beater containing the mixed pulps in an insufficiently diluted form, the mechanical wood pulp becomes more deeply coloured than the cellulose. If the former is a finely ground pulp, the effect is not very noticeable, but if it is coarse, containing a large number of coarse fibres, then the paper appears mottled. The defect is still further aggravated when the paper is calendered, especially if calendered in a damp condition. In that case the strongly coloured fibres of mechanical wood are very prominent. When dyes have been carelessly dissolved and added to the beating engine without being properly strained, unevenness of colour may often be traced to the presence of undissolved particles of dye. _Irregular Colour of the two Sides._--Many papers exhibit a marked difference in the colour of the two sides. When heavy pigments are employed as the colouring medium, the under side of the sheet, that is, the side of the paper in contact with the machine wire, is often darker than the top side. The suction of the vacuum boxes is the main cause of this defect, though the amount of water flowing on to the wire, the "shake" of the wire, and the extent to which the paper is sized are all contributory causes. By careful regulation of these varying conditions the trouble is considerably minimised. The under surface of the paper is not invariably darker than the top surface. With pigments of less specific gravity the reverse is found to be the case. This is probably to be explained by the fact that some of the colouring matter from the under side is drawn away from the paper by the suction boxes, and the pigment on the top side is not drawn away to any serious extent, because the layer of pulp below it acts as a filter and promotes a retention of colour on the top side. It is interesting to notice that this irregularity sometimes occurs with soluble dyes, as for example in the case of auramine. The decomposition of this dye when heated to the temperature of boiling water is well known, and the contact of a damp sheet of paper coloured by auramine with the surfaces of steam-heated cylinders at a high temperature brings about a partial decomposition of the dye on one side of the paper. Generally speaking, acid dyes are more sensitive to heat than basic dyes. The presence of china clay in a coloured paper is also an explanation of this irregular appearance of the two sides. China clay readily forms an insoluble lake with basic dyes, and when the suction boxes on the machine are worked with a high vacuum the paper is apt to be more deeply coloured one side than another. _The Machine Backwater._--Economy in the use of dyes to avoid a loss of the colouring matter in the "backwater," or waste water from the paper machine, is only obtained by careful attention to details of manufacture on the one hand and by a knowledge of the chemistry of dyeing on the other. The loss is partly avoided by regulating the amount of water used on the machine, so that very little actually goes to waste, and further reduced by ensuring as complete a precipitation of the soluble dye as possible. The _acid_ dyes generally do not give a colourless backwater, and all pulps require to be heavily sized when acid dyes are used. The _basic_ dyes are more readily precipitated than the acid dyes, particularly if a suitable mordant is used, even with heavily coloured papers. The addition of an acid dye to pulp first coloured with a basic dye is frequently resorted to as a means of more complete precipitation. _Dyeing to Sample._--The matching of colours has been greatly simplified through the publication of pattern books by the firms who manufacture dyes, in which books full details as to the composition of the paper, the proportion of colour and the conditions for maximum effects are fully set out. The precise results obtained by treating paper pulp with definite proportions of a certain dye, or a mixture of several dyes, is determined by experimental trials. A definite quantity of moist partially beaten and sized pulp, containing a known weight of air-dry fibre, is mixed with a suitable volume of water at a temperature of 80° to 90° F. and the dye-stuff added from a burette in the form of a 1 per cent. solution. If preferred a measured volume of a 1 per cent. solution of the dye can be placed in a mortar, and the moist pulp, previously squeezed out by hand, added gradually and well triturated with the pestle. The dyed mixture is then suitably diluted with water, made up into small sheets of paper on a hand mould or a siphon mould, and dried. The effect of small additions of colour to the contents of a beating engine is frequently examined in a rough and ready way by the beaterman, who pours a small quantity of the diluted pulp on the edge of the machine wire while the machine is running. This gives a little rough sheet of paper very quickly. The comparison of the colour of a beaterfull of pulp with the sample paper which it is desired to match is also effected by reducing a portion of the paper to the condition of pulp, so that a handful of the latter can be compared with a quantity of pulp from the engine. This is not always a reliable process, especially with papers coloured by dyes which are sensitive to the heat of the paper machine drying cylinders. _Detection of Colours in Papers._--The examination of coloured papers for the purpose of determining what dyes have been employed is a difficult task. With white papers which have been merely toned the proportion of dye is exceedingly small, and a large bulk of paper has to be treated with suitable solvents in order to obtain an extract containing sufficient dye for investigation. With coloured papers dyed by means of pigments, the colour of the ash left on ignition is some guide to the substance used, a red ash indicating iron oxide, a yellow ash chromate of lead, and so on. With papers dyed by means of coal tar colours the nature of the colouring matter may be determined by the methods of analysis employed for the examination of textile fibres. The following hints given by Kollmann will be found useful:-- Tear up small about 100 grammes of paper, and boil it in alcohol, in a flask or a reflux condenser. This must be done before the stripping with water, so as to extract the size which would otherwise protect the dye from the water. Of course the alcohol treatment is omitted with unsized paper. The paper is now boiled with from three to five lots of water, taking each time only just enough to cover the paper. This is done in the same flask after pouring off any alcohol that may have been used, and also with the reflux condenser. The watery extract is mixed with the alcohol extract (if any). Three cases may occur:--(1) The dye is entirely stripped, or very nearly so. (2) The dye is partly stripped, what remains on the fibres showing the same colour as at first or not. (3) The dye is not stripped. To make sure of this the solution is filtered, as the presence in it of minute fragments of fibre deceive the eye as to the stripping action. In the first two cases the mixed solutions are evaporated down to one half on the water bath, filtered, evaporated further, and then precipitated by saturating it with common salt. The dye is thrown out at once, or after a time. It may precipitate slowly without any salt. The precipitated dye is filtered off and dried. To see whether it is a single dye or a mixture, make a not too dark solution of a little of it in water, and hang up a strip of filter paper so that it is partly immersed in the solution. If the latter contains more than one dye they will usually be absorbed to different heights, so that the strip will show bands of different colours crossing it. If it is found that there is only one dye, dissolve some of it in as little water as possible, and mix it with "tannin-reagent," which is made by dissolving equal weights of tannin and sodium acetate in ten times the weight of either of water. If there is a precipitate there is a basic dye, if not, an acid dye. In the former case mix the strong solution of the dye with concentrated hydrochloric acid and zinc dust, and boil till the colour is destroyed. Then neutralise exactly with caustic soda, filter, and put a drop of the filtrate on to white filter paper. If the original colour soon reappears on drying, we draw the following conclusions:-- (_a_) The colour is red; the dye is an oxazine, thiazine, azine, or acridine dye, _e.g._, safranine. (_b_) It is orange or yellow; the dye is as in (_a_), _e.g._, phosphine. (_c_) It is green; the dye is as in (_a_), _e.g._, azine green. (_d_) It is blue; the dye is as in (_a_), _e.g._, Nile blue, new blue, fast blue, or methylene blue. (_e_) It is violet; the dye is as in (_a_), _e.g._, mauveine. If the original colour does not reappear on drying, but does so if padded with a 1 per cent. solution of chromic acid, we draw the following conclusions:-- (_a_) The colour is red; the dye is rhodamine or fuchsine, or one of their allies. (_b_) It is green; the dye is malachite green, brilliant green, or one of their allies. (_c_) It is blue; the dye is night blue, Victoria blue, or one of their allies. (_d_) It is violet; the dye is methyl violet, crystal violet, or one of their allies. If the original colour does not reappear even with chromic acid, it was in most cases a yellow or a brown, referable to auramine, chrysoidine, Bismarck brown, thioflavine, or one of their allies. If the tannin reagent produces no precipitate, reduce with hydrochloric acid and zinc, or ammonia and zinc, and neutralise and filter as in the case of a basic dye. The solution when dropped on to white filter paper may be bleached (_a_), may have become a brownish red (_b_), may have been imperfectly and slowly bleached (_c_), or may have undergone no change (_d_). (_a_) If the colour quickly returns the dye is azurine, indigo-carmine, nigrosine, or one of their allies. If it returns only on padding with a 1 per cent. solution of chromic acid, warming, and holding over ammonia, some of the dye is dissolved in water mixed with concentrated hydrochloric acid, and shaken up with ether. If the ether takes up the dye, we have aurine, eosine, erythrine, phloxine, erythrosine, or one of their allies. If it does not, we have acid fuchsine, acid green, fast green, water blue, patent blue, or one of their allies. If the colour never returns, heat some of the dye on platinum foil. If it deflagrates with coloured fumes, the dye is aurantia, naphthol yellow S., brilliant yellow, or one of their allies. If it does not deflagrate, or very slightly, dissolve a little of the dye in one hundred times its weight of water, and dye a cotton skein in it at the boil for about fifteen minutes. Then rinse and soap the skein vigorously. If the dyeing is fast with this treatment we have a substantive cotton yellow or thiazine red; if it is not, we have an ordinary azo dye. (_b_) The dye is an oxyketone, such as alizarine. (_c_) The dye is thiazol yellow, or one of its allies. (_d_) The dye is thioflavine S., quinoline yellow, or one of their allies. If the dye is not stripped by alcohol and water, it is either inorganic or an adjective dye, such as logwood black, cutch, fustic, etc.; and we proceed according to the colour as follows:-- If it is red or brown, the dyed fibre is dried and divided into two parts. One is boiled with bleaching powder. If it is bleached entirely or to a large extent, the dye is cutch. If the bleach has no action, incinerate some of the dyed fibre in an iron crucible and heat the ash on charcoal before the blowpipe. If a globule of lead is formed, we have saturn red. The second portion is boiled with concentrated hydrochloric acid. If there is no action, we have Cologne umber; if there is partial action, we have real umber; if the dye dissolves completely to a yellow solution, we have an ochre; if the solution is colourless instead of yellow, and chlorine is evolved during solution, we have manganese brown. If the colour is yellow or orange, boil with concentrated hydrochloric acid. If we get a green solution and a white residue, we infer chrome yellow or orange. If we get a yellow solution, we boil it with a drop or two of nitric acid and then add some ammonium sulphocyanide. A red colour shows an ochre or Sienna earth. If the colour is green, boil with caustic soda lye. If the fibre turns brown, we have chrome green. If no change takes place, boil with concentrated hydrochloric acid. A yellow solution shows green earth; a red colour logwood plus fustic. If the colour is blue or violet, boil with caustic soda lye. If the fibre turns brown, we have Prussian blue. If no change takes place, boil with concentrated hydrochloric acid. A yellow solution shows smalts. If the colour is destroyed, and the smell of rotten eggs is developed, we have ultramarine. If the colour is black, warm with concentrated hydrochloric acid containing a little tin salt. If the black is unchanged, we have a black pigment. If we get a pink to deep red solution we have logwood black. By means of the tests above detailed at length the group to which the dye belongs is discovered, and often the actual dye itself. Once the group is known it is generally easy, by means of the special reactions given in many books, _e.g._, in Schultz and Julius's "Tabellarische Übersicht," to identify the particular dye. When one has to deal with a single dye and simply desires to determine its group, the following table, due to J. Herzfeld, will suffice. Originally intended for textiles, it will serve, with some modifications here made in it, for the rapid testing of paper. 1.--RED AND REDDISH BROWN DYES. Boil the paper with a mixture of alcohol and sulphate of alumina. If no dye is extracted or a fluorescent solution is formed, we have an inorganic pigment, or eosine, phloxine, rhodamine, safranine, or one of their allies. Add bleaching powder solution, and heat. If the paper is bleached, add concentrated hydrochloric acid. A violet colour shows safranine or an analogue. If there is no colour, but the fluorescence disappears, we have eosine, phloxine, rhodamine, or one of their allies. If the paper is not bleached test for inorganic colouring matters. Cutch brown is partly but not entirely bleached. If the alumina solution gives a red or yellow solution without fluorescence, add to it concentrated sodium bisulphite. If bleaching takes place, heat a piece of the paper with dilute spirit. A red extract shows sandal wood, fuchsine, etc. If there is little or no extract, we have acid fuchsine or one of its allies. If the bisulphite causes no bleaching, boil a piece of the paper with very dilute hydrochloric acid. If the colour is unchanged, heat another piece of the paper with dilute acetate of lead. If no change takes place, we have an azo dye. If the colour turns to a dark brownish red, we have cochineal or the like. If the boiling with very dilute hydrochloric acid darkens the colour we have a substantive cotton dye. 2.--YELLOW AND ORANGE DYES. Heat some of the paper with a not too dilute solution of tin salt in hydrochloric acid. If the colour is unchanged, with a colourless or yellow solution, boil some more paper with milk of lime. A change to reddish or brown shows turmeric or a congener. Absence of change shows phosphine, quinoline yellow, or a natural dye-stuff. If the acid tin solution turns the paper red, and then quickly bleaches it to a pale yellow, we have fast yellow, orange IV., metanil yellow, brilliant yellow, or the like. If the tin turns the paper greyish, heat another portion with ammonium sulphide. A blackening shows a lead or iron yellow. If there is no change, we have naphthol yellow, auramine, azoflavine, orange II., chrysoidine, or one of their allies. 3.--GREEN DYES. Heat a sample of the paper in dilute spirit. If the spirit acquires no colour, warm for a short time with dilute sulphuric acid. If both paper and solution become brownish red, we have logwood plus fustic. If this fails, boil with concentrated hydrochloric acid. A yellow solution shows green earth. If this fails, boil with concentrated caustic soda. Browning shows chrome green. If the spirit becomes blue, it is a case of paper which has been topped with blue on a yellow, brown, or green ground. The solution and the insoluble part are separately tested. The case is probably one of an aniline blue dyed over a mineral pigment. If the spirit becomes green, heat with dilute hydrochloric acid. If the fibre is completely or nearly bleached, and the acid turns yellow, the dye is brilliant green, malachite green, or one of their allies. 4.--BLUE AND VIOLET DYES. Heat some of the paper with dilute spirit. If the alcohol remains colourless, we have Prussian blue or ultramarine. If it becomes blue or violet, shake some of the paper with concentrated sulphuric acid. A dirty olive green shows methylene blue, and a brownish colour shows spirit blue, water blue, Victoria blue, methyl violet, etc. If the spirit turns yellow, and the colour of the paper changes, we have wood blue or wood violet. CHAPTER XI PAPER MILL MACHINERY In the case of common printings and writings, which form the great bulk of the paper made, the possibility of one mill competing against another, apart from the important factor of the cost of freight, coal, and labour, is almost entirely determined by the economy resulting from the introduction of modern machinery. The equipment of an up-to-date paper mill, therefore, comprises all the latest devices for the efficient handling of large quantities of raw material, the economical production of steam, and the minimum consumption of coal, matters which are of course common to most industrial operations, together with the special machinery peculiar to the manufacture of paper. The amount of material to be handled may be seen from the table on page 215, which gives the approximate quantities for the weekly output of a common news and a good printing paper. _Economy in Coal Consumption._--The reduction to a minimum of the amount of coal required for a ton of paper has been brought about by the use of appliances for the better and more regular combustion of the coal, such as mechanical stokers, forced and induced draught, the introduction of methods for utilising waste heat in flue gases by economisers, and the waste heat in exhaust steam and condensed water by feed-water heaters, the adoption of machines for securing the whole energy of the live steam by means of superheaters, adequate insulation of steam mains and pipes, high pressure boilers, and engines of most recent design. The firing of steam boilers is now conducted on scientific principles, the coal being submitted regularly to proper analysis for calorific value, the evaporative power of the boilers being determined at intervals by adequate trials, the condition of the waste flue gases being automatically TABLE SHOWING THE MATERIALS REQUIRED FOR NEWS AND PRINTINGS. -----------------------------+--------------+------------------ -- | Common News.| Good Printings. -----------------------------+---------------+----------------- Weekly output of paper, say | 600 tons | 250 tons Mechanical wood pulp, moist, | | 50 per cent. dry | 800 " | Nil. Chemical wood pulp, dry | 200 " | 150 tons Esparto | Nil. | 200 " Soda ash | Nil. | 16 " Coal | 600 tons | 800 " Lime | Nil. | 45 " China clay | 60 tons | 25 " Bleach | Nil. | 30 " Alum, rosin, and chemicals | 20 tons | 20 " Water, per ton paper | 8,000 gallons| 40,000 gallons -----------------------------+---------------+----------------- _The Sarco Combustion Recorder._--This instrument is a device which automatically records the percentage of carbonic acid gas in the waste gases from boiler furnaces. The flue gases are analysed at frequent and regular intervals, and the results of the analysis can be seen on a chart immediately, so that it is possible to determine the effect of an alteration in the firing of the boilers within two minutes of its taking place. The apparatus is rather complicated, but the principle upon which it is based is simple. Measured quantities of the flue gases are drawn into graduated glass tubes and brought into contact with strong caustic soda solution, which absorbs all the carbonic acid gas. The remaining gases not absorbed by the caustic soda are automatically measured and the percentage of carbonic acid gas registered on the chart. The use of suitable boiler feed-water is also an important factor in modern steam-raising plant. The hot condensed water from the paper machine drying cylinders, and exhaust steam from the engines and steam-pipes, is returned to the stoke-hole to be utilised in heating up the cold water which has been previously softened by chemical treatment. [Illustration: FIG. 55.--Conventional Diagram of a Water Softening Plant. A. Water supply. B. Regulating tank. C. Lime mixer. D. Soda tank. E. Settling tank and filter. F. Outlet for softened water. ] _Water Softening._--The water softeners available on the market are numerous, and as each possesses special advantages of its own, it would be almost invidious to select any one for particular notice. They are based upon the principle of mixing chemicals with the water to be treated, so as to precipitate the matters in solution and give a boiler feed-water free from carbonates and sulphates of lime and magnesia. The chemicals are added in the form of solutions of carefully regulated strength to the water, which flow in a continuous stream into a tank. The flow of the water and chemical reagent is adjusted by previous analysis. The various machines differ in details of construction, and in the methods by which the mixing of the water and reagents is effected. The object to be achieved is the complete precipitation of the dissolved salts and the production of a clear water, free from sediment, in an apparatus that will treat a maximum quantity of water at a cheap rate per 1,000 gallons. The process needs proper attention. The addition of reagents in wrong proportions will do more harm than good, and possibly result in hardening the water instead of softening it. The following may be quoted as an example:-- ----------------------+-----------+-----------+------------ Composition of Water. | Before | After | Change. | Treatment.| Treatment.| ----------------------+-----------+-----------+------------ Calcium carbonate | 13·863 | 38·920 | 25·057 gain Calcium oxide (lime) | 0·0 | 14·300 | 14·300 " Calcium silicate | 2·062 | 3·591 | 1·529 " Calcium sulphate | 1·625 | 2·121 | 0·496 " Magnesia | 0·0 | 0·266 | 0·266 " Ferric oxide, etc. | 0·447 | 0·987 | 0·540 " +-----------+-----------+------------ Scale forming mineral| 17·997 | 60·185 | 42·188 gain +-----------+-----------+------------ Calcium chloride | 1·331 | 2·114 | 0·783 gain Magnesium chloride | 0·672 | 0·0 | 0·672 loss Sodium chloride | 0·478 | 0·476 | 0·003 " +-----------+-----------+------------ Soluble salts | 2·482 | 2·590 | 0·108 gain +-----------+-----------+------------ Total mineral matter | 20·479 | 62·776 | 42·297 gain +-----------+-----------+------------ Carbonic acid gas | 9·71 | 0·0 | 9·71 loss Oxygen gas | 0·66 | 0·66 | 0·0 " ----------------------+-----------+-----------+------------ Treatment required: 1·8 lbs. of lime, 0·2 lbs. soda ash per 1,000 gallons. Apparently 5·5 lbs. of lime were being used and no soda (Stromeyer). _Superheated Steam._--The effective application of the energy of the high pressure steam is probably one of the most important problems in paper mill economy. The use of superheated steam is being extended in every direction, and, in addition to the advantages obtained in the steam engine itself, its wider possibilities for the boiling of esparto, wood, and fibres generally have been noted. The following case may be quoted as the result of a trial at a paper mill, showing for stated conditions the advantages of superheated steam:-- --------------------------+-------------+---------- -- | Superheated | Ordinary | Steam. | Steam. --------------------------+-------------+---------- Duration of test hours | 26 | 34 | | Coal consumed (lbs.)-- | | Per hour | 610·5 | 661·5 Per 1 h.-p. hour | 1·83 | 2·08 | | Water evaporated (lbs.)-- | | Per hour | 4,832 | 5,679 Per 1 h.-p. hour | 14·55 | 17·8 From and at 212° F. | 8·7 | 8·94 | | Steam, temperature F. | 464 | 334 Pressure | 90·3 | 90·8 | | Steam engine-- | | 1 h.-p. total | 331·5 | 323·2 Temperature F. | 381·8 | 333·8 | | Coal used per 1 h.-p.-- | | Per hour at boiler | 1·83 | 2·08 --------------------------+-------------+---------- This appears to show a saving of 12 per cent. _Gas Producers._--The substitution of gas for steam in the paper mill has not yet proved a success. The fact that heat is required for the drying cylinders of a paper machine, and that the heat is most cheaply and readily obtained in the form of exhaust steam from the engines driving the paper machine, militates considerably against economies which might otherwise be possible. The difficulties of heating such cylinders, or rather of properly controlling and regulating the temperature by any other means than steam, may easily be surmised. Gas engines of over 200 h.-p. seem to give considerable trouble at present, but no doubt in course of time the required improvements will be effected. It is generally supposed that gas producers can only be economical when utilised for the production of gas on a large scale, and for distribution to engines of smaller capacity than the main steam engine required in a paper mill. The peculiar conditions of the manufacture of paper do not appear to be favourable to the adoption of the gas producer system in its present form. _Motive Power._--The paper-maker has taken advantage of every modern improvement in steam engines for the purpose of reducing the cost of motive power. Amongst other alterations in this direction the use of a high speed enclosed engine and the employment of the modern steam turbine may be noted. In the enclosed engine the working parts are boxed in by a casing fitted with oil-tight doors. The cranks and connecting rods splash into the oil, which is thus thrown about in all directions, so as to ensure sufficient lubrication. Another feature of this engine is the variable speed, and it is possible to run the paper machine at speeds varying from 100 to 500 ft. per minute without the use of change wheels. _Electrical Driving._--The application of electricity for motive power has made steady advances in the paper mill. At first it was limited to the driving of machinery in which variations of speed or load were not required to any large extent, but of recent years beating engines, calenders, and paper machines have all been fitted with electrical drives. [Illustration: FIG. 56.--An "enclosed" Steam Engine.] The following details relate to the installation at the Linwood Paper Mills:-- The installation consists of 250-K.W. steam dynamos. The engines are Willan's high speed triple expansion, working with a boiler pressure of 250 lbs. per square inch at the stop valve, the steam being superheated to give a temperature of 500° Fahr. at the engine. By means of jet condensers a vacuum of 25 to 25½ inches is obtained on the engines. The two boilers are of the Babcock type, and have 3,580 square feet of heating surface each. The furnaces have chain grate stokers, and the boilers are arranged with their own superheaters. The motor equipment consists of eight 80, two 50, and ten 25 B.H.P. motors. Six of the 80 B.H.P. drive the beating engines, and it has been found that the motors readily respond to an overload of 50 per cent. without beating or other trouble. To remedy the excessive and sudden variation a belt drive was adopted. An 80 motor drives the pulp refining engine. The two paper-making machines have each two motors, one a 25 and a 50 and the other two 25 B.H.P. motors. The speed can be regulated with exactitude. The auxiliary plant of the paper-making machine, pumps, agitators, etc., is worked from lines of shafting driven by motors. Calender motors are of the variable speed type, being designed to run from 100 revolutions per minute to 600 revolutions per minute. Variations from 300 to 600 revolutions per minute can be regulated by the shunts, the loss being negligible. Several of the motors are geared up to the various machines, as is the case with the calender. As regards cost, the capital outlay on the 500-K.W. generating plant, including engines, dynamos, boilers, condensers, steam pipes, filters, etc., and all engine room accessories, was £9,500. [Illustration: FIG. 57.--An Electrically Driven Paper Machine.] In addition to the above, the plant also contains a Parson's steam turbine of 1,000 K.W., driving two continuous current dynamos. [Illustration: FIG. 58.--Diagram of the "Eibel" Process.] _The Eibel Patent._--One of the most important improvements in connection with the manufacture of newspaper is the Eibel process, designed to increase the speed of the machine and to reduce the amount of suction at the vacuum box. In the ordinary machine the wire has usually been arranged to move in a horizontal plane. In some machines means have been provided for adjusting the breast-roll end of the wire to different elevations to provide for dealing with different grades of stock, but the wire has never hitherto been so inclined as to cause the paper stock to travel at a speed, under the action of gravity, to equal or approximate the speed of the wire. In all previous methods of working, the wire has for a considerable portion of its length, starting from the breast-roll, drawn the stock along in consequence of the wire moving much faster than the stock, and the stock has waved, or rippled, badly near the breast-roll end of the wire. This has gradually diminished until an equilibrium has been established and an even surface obtained, but not until the waving or rippling has ceased at some considerable distance from the breast-roll have the fibres become laid uniformly, and the machines have therefore necessarily been run slowly to give ample time for the water to escape and for the fibres to lie down so as to make them a uniform sheet. In many cases the breast-roll has been raised 14 or 15 inches, and the stock rushes, as it were, downhill. As, during the formation of the paper, the stock and the wire practically do not move relatively to each other, there is no drag of the stock upon the wire; consequently there is a more rapid and uniform drainage of the water from the stock, the full influence of the "shake" is made effective to secure uniformity in the distribution and interlocking of the fibres, and the regularity of the formation of the paper is not disturbed by waves or currents, which would otherwise be caused by pull of the wire upon the stock. This ingenious device is now working successfully in many paper mills. _Machinery._--In setting out the plant necessary for a paper mill which is designed to produce a given quantity of finished paper, the manufacturer takes into consideration the class of paper to be made and the raw material to be employed. The following schedule has been prepared on such a basis:-- PLANT AND MACHINERY FOR HIGH-CLASS PRINTINGS. _Paper._ High-class printings made of wood pulp and esparto, used alone or blended in varying proportions as required. Quantity, 250 tons weekly. _Raw Material._ Esparto; chemical wood pulp. Quantity: esparto, about 200 tons; wood pulp, 150 to 160. China clay and usual chemicals. In the estimation of materials required for the production of about 250 tons of paper, it is assumed that the 200 tons of esparto fibre will yield 90 tons bleached esparto fibre, and that the mechanical losses which take place during manufacture are counterbalanced by the weight of china clay added to the pulp. These conditions naturally vary in different mills, but such variations do not affect the schedule of machinery. _Unloading Sheds._ 2 steam or electric cranes for handling fibre, clay, alum, bleach, rosin, coal, and finished paper. 1 3-ton weighbridge. 1 5-cwt. platform scales. _Steam Plant._ 6 8-ft. by 30-ft. Lancashire boilers. Fuel economiser. Feed-water pump and tank. Water softening apparatus. 1 500-h.-p. main steam engine, for fibre departments and beater floor. _Chemical Department._ Hoist for clay, alum, bleach, lime, &c. 4 causticising pans, 9 ft. diameter, 9 ft. deep. 2 storage tanks. 2 chalk sludge filter presses. 2 clay-mixing vats, 6 ft. diameter, 6 ft. deep. 1 starch mixer, 6 ft. diameter, 6 ft. deep. 1 size boiler, 8 ft. diameter, 8 ft. deep. 3 size storage tanks, 1,000 gallons each. 3 bleach-mixing vats. 3 bleach liquor settling tanks. 2 clear bleach liquor storage tanks. 1 alum dissolving tank. _Recovery Department_:-- _Soda._ 1 multiple effect evaporating plant. 1 rotary furnace. 4 lixiviating tanks, 2,000 gallons each. 2 storage tanks for clear liquor from lixiviating tanks, 20,000 gallons capacity. _Fibre._ 2 tanks for receiving machine backwater. 2 Fullner's stuff catchers, or some other system of treating backwater. 2 filter presses. _Esparto Department._ 1 esparto duster. Travelling conveyer for cleaned esparto. 6 Sinclair vomiting boilers, each of 3 tons capacity. 2 measuring tanks for caustic liquor. 4 washing engines, 15 cwt. capacity. 6 Tower bleaching engines. 1 presse-pâte. 10 galvanised iron trucks. _Wood Pulp Department._ 4 pulp disintegrators and pumps. 4 Tower bleaching engines. 4 washing tanks or drainers. 6 galvanised iron trucks. _Beater Floor._ 8 1,200-lbs. beating engines. 2 Marshall refiners. 6 galvanised iron trucks. _Paper Machine Room._ 2 paper machines, 106 in. wide, with stuff chests, strainers, and engines complete. 1 paper machine, 120 in. wide, with stuff chests, strainers, and engines complete. Patent dampers for each machine. _Calendering Room._ 2 110-in. supercalenders. 2 100-in. supercalenders. 2 6-reel cutters. 1 200-h.-p. main steam engine. _Finishing Room._ Sorting tables. Packing press. Weighing machine. _Repairs Department._ Usual repair outfit, such as lathes, planing machine, drilling tools, etc. Blacksmith's shop outfit. Carpenter's shop outfit. Calender roll grinder. _Water Supply._ Main storage tank, 50,000 gallons capacity. Water pumps. Piping and connections to various departments. Bell's patent filters (if necessary). CHAPTER XII THE DETERIORATION OF PAPER Recent complaints about the quality of paper and the rapid decay of manuscripts and papers have resulted in arousing some interest in the subject of the durability of paper used for books and legal documents, and in the equally important question of the ink employed. The Society of Arts and the Library Association in England and the Imperial Paper Testing Institute in Germany have already appointed special committees of inquiry, and from this it is evident that the subject is one of urgent importance. It is sometimes argued that the lack of durability is due to the want of care on the part of manufacturers in preserving the knowledge of paper-making as handed down by the early pioneers, but such an argument is superficial and utterly erroneous. The quality of paper, in common with the quality of many other articles of commerce, has suffered because the demand for a really good high-class material is so small. The general public has become accustomed to ask for something cheap, and since the reduction in price is only rendered possible by the use of cheap raw material and less expensive methods of manufacture, the paper of the present day, with certain exceptions, is inferior to that of fifty years ago. The causes which favour the deterioration of paper are best understood by an inquiry into the nature of the fibres and other materials used and the methods of manufacture employed. _The Fibres Used._--Cotton and linen rags stand preeminent amongst vegetable fibres as being the most suitable for the production of high-class paper capable of withstanding the ravages of time. This arises from the fact that cotton and linen require the least amount of chemical treatment to convert them into paper pulp, since they are almost pure cellulose, cotton containing 98·7 per cent. of air-dry cellulose, and flax 90·6 per cent. The processes through which the raw cotton and flax are passed for the manufacture of textile goods are of the simplest character, and the rags themselves can be converted into paper without chemical treatment if necessary. As a matter of fact certain papers, such as the O. W. S. and other drawing papers, are manufactured from rags without the aid of caustic soda, bleach, or chemicals. The rags are carefully selected, boiled for a long time in plain water, broken up and beaten into pulp, and made up into sheets by purely mechanical methods. The liability of papers to decay, in respect of the fibrous composition, is almost in direct proportion to the severity of the chemical treatment necessary to convert the raw material into cellulose, and the extent of the deviation of the fibre from pure cellulose is a measure of the degradation which is to be expected. The behaviour of the fibres towards caustic soda or any similar hydrolytic agent serves to distinguish the fibres of maximum durability from those of lesser resistance. It may be noted that in the former the raw materials, viz., cotton, linen, hemp, ramie, etc., contain a high percentage of pure cellulose, while in the latter the percentage of cellulose is very much lower, such fibres as esparto, straw, wood, bamboo, etc., giving only 40-50 per cent. of cellulose. The two extremes are represented by pure cotton rag and mechanical wood pulp. Other things being equal, the decay which may take place in papers containing the fibre only, without the admixture of size or chemicals, may be considered as one of oxidation, which takes place slowly in cotton, and much more rapidly with mechanical wood pulp. Experimental evidence of this oxidation is afforded when thin sheets of paper made from these materials are exposed to a temperature of 100° to 110° C. in an air oven. The cotton paper is but little affected, while the mechanical wood pulp paper soon falls to pieces. The order of durability of various papers in relation to the fibrous constituents may be expressed thus: (1) rag cellulose; (2) chemical wood cellulose; (3) esparto, straw, and bamboo celluloses; (4) mechanical wood pulp. The rate and extent of oxidation is approximately shown by the effect of heat as described. The differences between the celluloses are also shown by heating strips of various papers in a weak solution of aniline sulphate, which has no effect on wood or rag cellulose, dyes esparto and straw a pinkish colour, and imparts a strong yellow colour to mechanical wood pulp and jute. _Physical Qualities._--The permanence of a paper depends not only upon the purity of the fibrous constituents and the freedom from chemicals likely to bring about deterioration, but also upon the general physical properties of the paper itself. Other things being equal, the more resistant a paper is to rough usage the longer will it last. The reason why rag papers are so permanent is that not only is the chemical condition of the cellulose of the highest order, but the physical structure of the fibre is such that the strength of the finished paper is also a maximum. The methods of manufacture may be modified to almost any extent, giving on the one hand a paper of extraordinary toughness, or on the other hand a paper which falls to pieces after a very short time. Thus a strong bank-note paper may be crumpled up between the fingers three or four hundred times without tearing, while an imitation art paper is broken up when crumpled three or four times. A thorough study of the physical qualities of a paper is therefore necessary to an appreciation of the conditions for durability. The physical structure of the fibre, the modifications produced in it by beating, the effect of drying, sizing, and glazing upon the strength and elasticity of the finished paper, are some of the factors which need to be considered. _Strength._--The strength of a paper as measured by the tensile strain required to fracture a strip of given width, and the percentage of elongation which the paper undergoes when submitted to tension, are properties of the utmost importance. The elasticity, that is, the amount of stretch under tension, has not received the attention from paper-makers that it deserves. If two papers of equal tensile strength differ in elasticity, it may be taken for granted that the paper showing a greater percentage of elongation under tension is the better of the two. The strength of a paper, as already indicated, is greatly influenced by the conditions of manufacture. This has been explained in the chapter devoted to the subject of beating, and other examples are briefly given in the following paragraphs. _Bulk._--The manufacture during recent years of light bulky papers for book production has accentuated the problem in a marked degree, and the factor of _bulk_ as one of the causes of deterioration is therefore a comparatively new one. It is interesting to notice that the rapid destruction of such books by frequent use is in no way related to the chemical purity of the cellulose of which it is composed, or to the influence of any chemical substance associated with the fibre. It is purely a mechanical question, to be explained by reference to the process of manufacture. This paper is made from esparto entirely, or from a mixture of esparto and wood pulp. The pulp is beaten quickly, and for as short a time as possible, little or no china clay being added, and only a very small percentage of rosin size. The wet sheet of paper is submitted to very light pressure at the press rolls, and the bulky nature is preserved by omitting the ordinary methods of calendering. The paper thus produced consists of fibres which are but little felted together. The physical condition and structure of the paper are readily noticeable to the eye, and when these peculiarities are reduced to numerical terms the effect of the conditions of manufacture is strikingly displayed. The effect of this special treatment is best seen by contrasting the bulky esparto featherweight paper with the normal magazine paper made from esparto. In the latter case a smoother, heavier, stronger sheet of paper is made from identically the same raw material. But the pulp is beaten for a longer period, while mineral matter and size are added in suitable proportions. The press rolls and calenders are used to the fullest extent. The difference between these two papers, both consisting, as they do, of pure esparto with a small proportion of ash may be emphasised by comparing the analysis by _weight_ with analysis by _volume_. The two papers in question when analysed by weight proved to have the following composition:-- -------------------------------------------- | Parts by Weight. +----------------+------------ -- | Featherweight. | Ordinary. --------------+----------------+------------ Esparto fibre | 96·0 | 95·4 Ash, etc | 4·0 | 4·6 | ----- | ----- | 100·0 | 100·0 --------------+----------------+------------ But if the papers are compared in terms of the _composition by volume_, it will be found that the featherweight contains a large amount of air space. --------------+----------------------------- | Composition by Volume. +----------------+------------ -- | Featherweight. | Ordinary. --------------+----------------+------------ Esparto fibre | 28·0 | 65·5 Ash, etc | 0·7 | 1·8 Air space | 71·3 | 32·7 | ----- | ----- | 100·0 | 100·0 --------------+----------------+------------ In other words, the conditions of manufacture for the bulky paper are such that the fibres are as far apart from one another as possible, and the cohesion of fibre to fibre is reduced to a minimum. While paper of this description is agreeable to the printer, and probably to the general reading public, yet its strength and physical qualities, from the point of view of resistance to wear and tear, are of the lowest order. It is very difficult to rebind books made from it, which is not altogether to be wondered at, seeing that the bookbinder's stitches can hardly be expected to hold together sheets containing 60 to 70 per cent. of air space. This concrete case emphasises the necessity for including in a schedule of standards of quality a classification of papers according to strength and bulk. _Surface._--The introduction of new methods of printing has brought about some changes in the process of glazing and finishing paper which are not altogether favourable to the manufacture of a sheet having maximum qualities of strength and elasticity, two conditions which are essential to permanence. In other words, the very high finish and surface imparted to paper by plate-glazing, supercalendering, water finish, and other devices of a similar character is carried to excess. All papers are improved in strength by glazing up to a certain point, but over-glazing crushes the paper, renders it brittle and liable to crack. Unfortunately, the maximum strength of a paper is generally reached before the maximum of finish, with the result that the former is frequently sacrificed to the latter. The usual result of glazing is found in an increase of 8 to 10 per cent. in the tensile strength, but a diminution of elasticity to the extent of 8 to 10 per cent. With supercalendered magazine papers, the high surface is imparted for the sake of the illustrations which are produced by methods requiring it. The addition of considerable quantities of clay or mineral substances improves the finish, so that the question of the relation of glazing to strength, surface, and loading is one which affects the subject of deterioration of paper very materially. With writing paper the false standard of an "attractive" appearance is almost universally accepted by the public as the basis of purchase without any reference to actual quality. _Mineral Substances._--China clay, sulphate of lime, agalite and other inert mineral substances are important factors in lowering the quality of paper, not so much in promoting the actual deterioration of paper by any chemical reaction with the fibres, as in making the paper less capable of resistance to the influence of atmospheric conditions and ordinary usage. Clay in small, well-defined quantities serves a useful purpose, if added to some papers, because it favours the production of a smooth surface, but when the combination of mineral substances is carried to an extreme, then the result from the point of view of permanence is disastrous. This is well recognised by all paper-makers, and in Germany the limits of the amount of clay or loading in high-grade paper have been rigidly fixed. In the case of _imitation art_ paper, which contains 25 to 30 per cent. of its weight of clay, the strength and resistance of the sheet is reduced to a minimum. The paper falls to pieces if slightly damped, the felting power of the fibres being rendered of no effect owing to the weakening influence of excessive mineral matter. This paper is used chiefly for catalogues, programmes, circulars, and printed matter of a temporary and evanescent character, and so long as it is confined to such objects it serves a useful purpose, being cheap, and suitable for the production of illustrations by means of the half-tone process; but its lasting qualities are of the lowest order. The addition of 10 per cent. of any mineral substance must be regarded as the maximum allowance for papers intended for permanent and frequent use. _Coating Material._--The ingenious method for producing an absolutely even surface on paper by the use of a mixture of clay or other mineral substance and an adhesive like glue or casein brushed on to the surface of the paper, is responsible for many of the complaints about the papers of the present day. The sole merit of this substance is the facility with which half-tone process blocks can be utilised for the purpose of picture production. Beyond this, nothing can be said. The paper is brittle, susceptible to the least suspicion of dampness, with a high polish which in artificial light produces fatigue of the reader's eye very quickly, heavy to handle, and liable to fall to pieces when bound up in book form. As the fibrous material is completely covered by mineral substances, it is frequently considered of secondary importance, with the result that the "value" of the paper is judged entirely by the surface coating, with little regard to the nature of the body paper. In such cases, with an inferior body paper, the pages of a book very quickly discolour, and the letterpress becomes blurred. ANALYSIS OF A TYPICAL ART PAPER. ---------+-----------+-----------+------------ | Per Cent. | | Volume -- | by | -- | Composition | Weight. | | per Cent. ---------+-----------+-----------+------------ Fibre | 77·5 | Fibre | 68·3 Ash, etc.| 22·5 | Ash | 12·0 | | Air space | 19·7 | ----- | | ----- | 100·0 | | 100·0 ---------+-----------+-----------+------------ _Rosin._--The presence of an excess of rosin is a well-known factor in the disintegration of the paper, even when the fibrous composition is of the highest order. The decomposition is largely due to the action of light, many experiments having been made by Herzberg and others to determine the nature of the reactions taking place. One of the chief alterations is the change brought about in the ink-resisting qualities of the paper. The actual character of the chemical reactions as far as the effect on the fibre is concerned is not accurately known. The degradation of a hard-sized rosin paper by exposure to strong sunlight, for example, is probably due to the alteration in the rosin size, and not to any material change in the cellulose. It is hardly conceivable that in a pure rag paper sized with rosin and yielding readily to ink penetration, after about one year's exposure to light, the cellulose itself had undergone any chemical changes capable of detection. _Gelatine._--Papers properly sized with gelatine are preferable to those sized with rosin for the majority of books and documents preserved under normal circumstances. But the nature of a tub-sized paper may be, and often is, greatly altered by unusual climatic conditions. In hot, damp countries papers are quickly ruined, and high-class drawing papers sized with gelatine often rendered useless. The change is scarcely visible on the clean paper, and is only observed when the paper is used for water-colour work, the colour appearing blotchy in various parts of the sheet where the gelatine has been decomposed by the united action of heat and damp. The artist is frequently compelled in such cases to put a layer of heavy white colour on the sheet of paper before proceeding to paint the picture. The storage of books under favourable conditions has a great deal to do with the permanence of the paper, and the degradation of a paper in relation to the tub-sizing qualities is much hastened by the presence of moisture in the air. _Starch._--The same is true of starch, which is largely employed as a binding or sizing material in paper. The degradation of gelatine, starch, and similar nitrogenous substances is due to the action of organisms, and the following experiments, suggested by Cross, are interesting in this connection. If strips of paper are put into stoppered bottles with a small quantity of warm water and kept at a temperature of about 80° F., fungus growths will be noticed on some of them after the lapse of fourteen days. Rag papers sized with gelatine will show micro-organisms of all kinds. A pure cellulose paper, like filter paper, will not produce any such effects. The result in the first case is due to the nitrogenous substance, viz., the gelatine used in sizing, since the two papers are identical as far as the cellulose fibres are concerned. High-class wood pulp papers, unless sized with gelatine, would not show similar results. The action of the organisms upon the nitrogenous material by a process of hydrolysis is in the direction of the production of soluble compounds allied to the starch sugars capable of being assimilated by organisms. The cellulose of esparto and straw are readily attacked, and it is on this account that the tissues of the various straws are digested more or less when eaten by animals. It is for this reason that the celluloses from straw and esparto are inferior to the cotton cellulose in producing a paper likely to be permanent. _Chemical Residues._--The necessity for manufacturing a pure cellulose half-stuff is fully recognised by paper-makers. This was not the case in the early days of the manufacture of wood pulp, for it is a matter of common experience that many of the books printed on wood pulp paper between 1870 and 1880 are in a hopeless condition, and it is quite easy to find books and periodicals of that date the pages of which crumble to dust when handled. This serious defect has been proved to be due to the presence of traces of chemicals used in manufacture which have not been thoroughly removed from the pulp. The precautions necessary in bleaching pulp by means of chloride of lime, in order to prevent (1) any action between the fibre and the calcium hypochlorite, (2) the presence of residual chlorine or soluble compounds derived from it, and (3) the presence of by-products arising from the use of an antichlor, are also well known to paper-makers. The subject has been closely studied by chemists, who have shown that the deterioration of many modern papers may be ascribed to carelessness in bleaching. The questions relating to the chemical residues of paper can only be adequately dealt with by a discussion of actual cases which arise from time to time. There are certain conditions in manufacture, common to all papers, which may give rise to the presence of chemical residues, of which two have already been mentioned. The acidity of papers is frequently quoted as an instance. It is true that the presence of free acid in a paper is most undesirable, as it seriously attacks the cellulose, converting it into an oxidised form. This in course of time renders the paper so brittle as to destroy its fibrous character. The change is brought about by the acid, which itself suffers no material alteration, so that the process of deterioration is continued almost indefinitely until the cellulose is completely oxidised. Most papers, however, show an acid reaction when tested with litmus, the usual reagent employed by those not familiar with the proper methods of testing paper. All papers which have been treated with an excess of alum for sizing purposes would show an acid reaction with litmus without necessarily containing any free acid. The presence of iron is undesirable, particularly in photographic papers, and since cellulose has a remarkable affinity for iron, the conditions of manufacture which tend to leave iron in the pulp have to be taken into consideration. The presence of minute quantities of iron in the form of impurities must not be confused with the presence of iron in large quantities derived from the toning and colouring of paper by means of iron salts. The fading of colour is frequently observed when coloured papers are tested on boxboards, particularly those made of straw. This fading may often be traced to the presence of alkali in the straw board which has not been completely removed in the process of manufacture. The blurring of letterpress is a defect which often occurs with printing papers made of chemical wood pulp. The oil in the ink seems to separate out on either side of the letter, producing a discoloration. In such cases the paper itself frequently exhibits an unpleasant smell. These defects are usually determined by the presence of traces of sulphur compounds in the paper resulting from incomplete washing of the pulp in manufacture. The presence of sulphur compounds sometimes associates itself with papers which have been coloured by means of ultramarine, which in presence of alum is slightly decomposed by the heat of the drying cylinders. Some knowledge of the effect of chemical residues in paper is important, not only in regard to the deterioration which takes place in the fibre itself, but also in relation to the fading of the ink which is used. The subject of the ink has received much attention from chemists on account of the serious difficulties which have been experienced by State departments in various countries. The United States Department of Agriculture have devised certain methods for ascertaining the suitability of stamping ink used by the Government and suggest the qualities desirable in such an ink. The ink, first of all, must produce an indelible cancellation; that is, it must be relatively indelible as compared with the ink used for printing the postage stamps. The post-mark made with the ink must dry quickly in order that the mail matter may be handled immediately without any blurring or smearing of the post-mark. Both this property and the property of the indelibility involve the question of the rate at which the ink penetrates or is absorbed by the fibre of the paper. A satisfactory ink does not harden or form a crust on the ink-pad on exposure to air. There must be no deposition of solid matter on the bottom of the vessel in which the ink is stored, and the pigments on which the indelibility of the ink depends, if insoluble, must not settle out in such a way as to make it possible to pour off from the top of the container a portion of the ink which contains little or none of the insoluble pigment or pigments. _Colour._--If the subject of deterioration of paper is to be considered in its broadest sense as including changes of any kind, the fading of colour must be taken into account. The use of aniline dyes which are not fast to light results in a loss of colour in paper just as with textiles, and the fading may be regarded as a function of the dye and not as arising from its combination with the paper. The gradual fading of some dyes, however, and of many water-colour pigments may be traced to the presence of residual chemicals in the paper and to the presence of moisture in an atmosphere impregnated with gaseous or suspended impurities. In fact the latter is a greater enemy to permanence of colour than light, since it has been proved by experiment that most colours do not fade when exposed to light in a vacuum. The oxygen of the air in combination with the moisture present is the principal agent in bringing about such changes. The dulling of bronze, or imitation gold leaf, on cover papers is a practical illustration of this, though this can hardly be quoted as an instance of actual deterioration of the paper. The maintenance of the original colour can only be assured by the careful selection of pure fibrous material, the use of fast dyes, and the preservation of the book or painting from the conditions which favour the fading as described above. For common papers such precautions become impossible, but for water-colour drawings and valuable papers they are essential. The demand for an abnormally white paper is indirectly the cause of deterioration in colour, but in this case the ultimate effect is not a fading but a discoloration of white to a more or less distinct yellow or brown colour, due to changes in the fibre which may often be traced to excessive bleaching. In this case the fading of colour is directly due to deterioration of the paper itself, and may occur in celluloses of the best type. With lower-grade papers containing mechanical wood pulp the degradation of colour and fibre is inevitable. _Air and Moisture._--The exact effects produced on paper freely exposed, or in books as ordinarily stored, depend upon the condition of the atmosphere. Pure air has little or no action upon paper, cellulose being a remarkably inert substance, and even in impure mechanical wood pulp, if merely exposed to pure dry air, the signs of decay would be delayed considerably. The combined action of air and moisture is of a more vigorous character in promoting oxidation changes in the fibres, or a dissociation of the sizing and other chemical ingredients of the paper. The presence of moisture is, indeed, absolutely essential for the reaction of some substances upon one another, and it is easy to show that certain chemical compounds can be left in ultimate contact, if absolutely dry, for a lengthened period without reacting, but the addition of a little moisture at once produces chemical union. This may be shown by a simple experiment. Thus a piece of coloured paper which may be bleached immediately if suspended in an atmosphere of ordinary chlorine gas will remain unbleached for several hours if first thoroughly dried in an oven and exposed to dry gas. In the case of books and papers, these conditions which promote slow disintegration are aggravated by the presence of impurities in the air, such as the vapours of burning gas, the traces of acidity in the atmosphere of large manufacturing towns, the excessive dampness and perhaps heat of a climate favouring the growth of organisms. All these factors are of varying degrees in different places, so that the deterioration of papers does not proceed in the same measure and at the same rate everywhere. _Moisture._--It may not be out of place to discuss some important relations between moisture and the physical qualities of a sheet of paper. A paper in its normal condition always contains a certain proportion of water as one of its ingredients, and the presence of this moisture has much to do with the strength, elasticity, and use of the paper, the absence of moisture giving rise to defects and troubles in the use of the paper which to a certain extent lower its commercial value and deteriorate it, though not perhaps in the sense of permanent degradation of quality. One trouble frequently experienced by stationers and others is that known as wavy edges. The edges of a stack containing sheets of paper piled upon one another frequently twist and curl, producing what are known as wavy edges. This arises from the fact that the paper when manufactured was deficient in natural moisture, and that when stacked it has gradually absorbed moisture, which is taken up first by the edges exposed to the air. This causes unequal expansion of the fibres with the production of the so-called wavy edges. The only remedy in such cases is the free exposure of the sheets before printing, so that the moisture is absorbed equally all over the sheet. The cracked edges of envelopes may be explained by reference to the same conditions. The paper is worked up into envelopes in an over-dry condition, and the fibres, being somewhat brittle, readily break apart from one another. If the paper is kept in stock for some time before use this defect can be very largely remedied. With supercalendered papers it is only possible to obtain the best results by allowing the paper to stand for several days after making before it is glazed. It is evident from these few examples that many of the troubles experienced by printers are due to the fact that orders for paper are frequently accompanied by an instruction for immediate delivery, under which circumstances it is impossible to obtain the best results. The expansion of papers used for lithography, and the bad register frequently seen in colour work, may be explained by reference to the behaviour of the individual fibres towards moisture. The expansion is usually greater in one direction of the paper than in the direction at right angles to it, and this is due to the fact that fibres have a greater ratio of expansion in the diameter than in the length. The behaviour of papers when damped is a peculiarity well known to paper-makers and printers. For certain purposes it is desirable that paper should not show any material alteration when damped, since any expansion of the sheet is liable to throw the printing out of "register." The liability of papers to such stretch or expansion is largely minimised by careful manipulation of the pulp during the process of beating, and also by a proper regulation of the web of paper as it passes from the wet end of the paper machine over the drying cylinders to the calenders. The paper which fulfils the necessary qualifications as to a minimum stretch is prepared from pulp which has not been beaten for too long a period, so that the pulp obtained is fairly light and bulky. By this means the expansion of the fibres takes place in the sheet itself without making any material alteration in its size. That is to say, as the sheet of paper is fairly _open_, there is sufficient room for expansion, which thus takes place with the least alteration of the total area of the sheet. The paper which is allowed to shrink on the machine during the process of drying, without undue tension, usually exhibits a minimum amount of expansion subsequently in printing. It is important to notice that the expansion of paper is different for the two directions, that is for the machine and cross directions. This arises from the fact that in the machine-made paper the greater proportion of the fibres point in the direction of the machine while the paper is being made. In consequence of this the expansion of the paper is greatest in what is known as the cross direction of the paper, that is, in the direction at right angles to the flow of the pulp along the machine wire. This is to be explained by reference to the behaviour of fibres when damped or brought into contact with an excess of water. The question of the exact changes in the dimensions of a fibre due to absorption of water has been dealt with in an interesting manner by Hohnel. He points out that the well-known peculiarity of the shrinkage of ropes which have been lying in the water can be explained by an examination of the behaviour of the single fibres. He relates in detail the experiment which can be carried out for the exact observation of the fibres when in contact with water. A dry fibre when soaked in water appears to become 20 to 30 per cent. greater in diameter, whereas in length it is usually only increased by one-tenth per cent. The method adopted by Hohnel was to place a fibre of convenient length on a glass slip down the centre of which was a fine narrow groove capable of holding water, so that the fibre could be wetted. Over the fibre was a cover glass with a small scale marked on it. The loose end of the fibres passed over a small roller and was stretched by a light weight. The movements of the fibre were measured by means of an eye-piece micrometer. In this way it is possible to determine alterations in length to within 0·005 per cent., and this variation can be directly seen under the microscope. Hohnel observes in his account of the experiments that all fibres become thicker when wetted, that vegetable fibres are more susceptible than animal fibres. Animal fibres expand about 10 to 14 per cent. in diameter, but vegetable fibres as much as 20 per cent., as shown in the following table:-- -------------+----------+------------------+---------- Animal Fibre.| Per Cent.| Vegetable Fibre. | Per Cent. -------------+----------+------------------+---------- Human hair | 10·67 | New Zealand flax | 20·0 Angora wool | 10·2 | Aloe hemp | 25·8 Alpaca wool | 13·7 | Hemp | 22·7 Tussah silk | 11·0 | Cotton | 27·5 -------------+----------+------------------+---------- The reverse is the case when the expansion of the fibres in regard to length is considered, since animal fibres expand 0·50 to 1·00 per cent. of their length, and vegetable fibres only 0·05 to 0·10 per cent. The maximum amount of expansion in the case of the vegetable fibres is obtained by gently breathing upon them rather than by the use of an excess of water. These figures are important as explaining many of the peculiar characteristics of vegetable and animal fibres. Advantage is taken of the greater expansion of the latter in the manufacture of instruments for the measurement of moisture, such as the hair hygrometer, in which the elongation of a stretched hair registers the variation in the moisture of the atmosphere. _Quality of Book Papers._--The Committee of the Society of Arts in dealing with the evidence as to the permanence of finished papers suggest the following classification as indicating the desired standards of quality:-- (A) CLASSIFICATION AS TO FIBRES. A. Cotton, flax, and hemp. B. Wood celluloses, (_a_) sulphite process, and (_b_) soda and sulphate process. C. Esparto and straw celluloses. D. Mechanical wood pulp. The Committee find little fault with the Principles which govern the trade in the manufacture of high-class papers, and limit the result of their investigation to the suggestion of a normal standard of quality for book papers required in documents of importance according to the following schedule:-- _Fibres._--Not less than 70 per cent. of fibres of Class A. _Sizing._--Not more than 2 per cent. rosin, and finished with the normal acidity of pure alum. _Loading._--Not more than 10 per cent. total mineral matter (ash). With regard to written documents, it must be evident that the proper materials are those of Class A, and that the paper should be pure, sized with gelatine and not with rosin. All imitations of high-class writing papers, which are in fact merely disguised printing papers, should be carefully avoided. These recommendations are good as far as they go, but in order to establish the proper standards of quality some specifications must be laid down with regard to the strength of the paper and its physical properties, together with a reference to the use for which the paper is intended. The physical condition of the paper itself apart from the nature of the fibre has much to do with its resistance to wear and tear, and this is easily proved by comparing modern book papers made from esparto with book papers of an earlier date made from the same material. The only official schedule of requirements in relation to public documents is that issued by the Stationery Office. The details set out relate chiefly to questions of weight and strength, the limits being expressed in definite form and not allowing much margin for variation in respect of strength or fibrous constituents. Mechanical wood pulp is excluded in all papers except common material as stated in the schedule. The papers required for stock are divided into twelve classes. In each class the trade names of various sized papers are given, the size of the sheet and the weight of the ream, and, where required, any special characteristics are set out. The schedule is as follows:-- _Class 1. Hand-made or Mould-made._ _General Specification._--Hand-made or mould-made. Animal tub-sized. ("Hand-made" or "Mould-made" to be marked on the wrapper.) Where special water-marking is required mould will be supplied by the Stationery Office for those papers made by hand. _Class 2. Writings, Air-dried._ _General Specification._--Plate rolled. Machine made. Animal tub-sized. Air-dried. (Must bear ink after erasure.) _Note._--The mean breaking strain and mean stretch required are given for each paper. The figures represent the mean of the results obtained for both directions of the sheet, and are calculated on a strip of paper five-eighths of an inch wide and having a free length of seven inches between the clips. _Class 3. Writings, Ordinary._ _General Specification._--Rolled. Machine-made. Animal tub-sized. _Class 4. Writings, Coloured._ _Specification._--Highly rolled. Machine-made. Animal tub-sized. _Class 5. Blotting Papers._ _Specification._--All rag. Machine-made. Free from loading. _Class 6. Printing and Lithographic Papers._ _General Specification._--Rolled. Machine-made. Engine-sized. Loading not to exceed 15 per cent. _Class 7. Coloured Printings._ _General Specification._--Rolled. Machine-made. Engine-sized. _Class 8. Copying and Tissue Papers._ _Specification._--Machine-made. Free from loading. (Copying papers are required to give three good copies.) _Class 9. Brown Papers, Air-dried._ _Specification._--Air-dried. Machine-made. _Note._--The mean breaking strain and mean stretch required are given for each paper. The figures represent the mean of the results obtained for both directions of the sheet, and are calculated on a strip of paper two inches wide and having a free length of seven inches between the clips. In the case of papers indicating a larger breaking strain than the minimum required, a proportional increase in the stretch must also be shown. _Class 10. Brown Paper, Cylinder-dried._ _General Specification._--Machine-made. _Note._--The mean breaking strain required is given for each paper. The figures represent the mean of the results obtained for both directions of the sheet, and are calculated on a strip of paper two inches wide and having a free length of seven inches between the clips. _Class 11. Smallhands._ _General Specification._--Machine-made. Engine-sized. _Class 12. Buff Papers._ _Specification._--Highly finished both sides. Machine-made. Hard engine-sized. Mechanical wood pulp must not be used in the manufacture of any papers, with the exception of engine-sized coloured printings, and buff papers, where an addition up to 25 per cent. will be allowed. All animal tub-sized papers are required to be as far as possible free from earthy matter; and, except where specially stated, the amount of _loading_ added to other papers must not exceed 6 per cent. When sulphite or soda pulps are used, either separately or conjointly, in the manufacture of printing papers, the quantity of neither material shall separately exceed 50 per cent. The most complete specification as to the requirements for standard papers is that published by the Paper Testing Institute in Germany, and used as the basis of most contracts, at least for public and official documents. _Standards of Quality in Germany._--The classification of papers according to the raw materials used and the nature of the finished paper is very complete. The classification is made under three headings: (_A_) Raw Material; (_B_) Strength; (_C_) Uses. _(A) Classification according to Material._ (1) Paper made from rags only (linen, hemp, and cotton). (2) Paper made from rags with a maximum of 25 per cent. of cellulose from wood, straw, esparto, manila, etc., but free from mechanical wood pulp. (3) Paper made from any fibrous material, but free from mechanical wood pulp. (4) Paper of any fibrous material. _(B) Classification according to Strength._ ----------------------+-------+-------+-------+-------+-------+------ Class | 1. | 2. | 3. | 4. | 5. | 6. ----------------------+-------+-------+-------+-------+-------+------ Mean tearing length | | | | | | in metres | 6,000 | 5,000 | 4,000 | 3,000 | 2,000 | 1,000 | | | | | | Elasticity per cent. | 4 | 3·5 | 3 | 2·5 | 2 | 1·5 | | | | | | Resistance to folding | | | | | | (Schoppers' method, | | | | | | number of foldings) | 190 | 190 | 80 | 40 | 20 | 3 ----------------------+-------+-------+-------+-------+-------+------ The tests for tearing length, resistance to folding, elasticity, etc., are made in air showing relative humidity of 65 per cent. The calculations for tearing length are made on strips of paper dried at 100° C. _(C) Classification according to Use._ ------+-------------------+------+----------+-----------+--------------- | | | | | Weight of | |Fibre.| Strength.| Size of +-------+------- Class.| Uses. |Class.| Class. | Sheets. | 1,000 | 1 Sq. | | | | Cm. |Sheets.| Metre. | | | | | Kg. | Grms. --+---+-------------------+------+----------+-----------+-------+------- 1 | Writing papers for | | | | | | important documents | 1 | 1 | 33 × 42 | 15 | -- | | | | | | | Paper for State | | | | | | documents | 1 | 1 | 26·5 × 42 | 12 | -- | | | | | | 2 | Paper for registers, | | | | | | account books, | | | | | | and ledgers-- | | | | | | | | | | | | (_a_) First quality | 1 | 2 | 33 × 42 | 14 | -- | | | | | | | (_b_) Second quality | 1 | 3 | 33 × 42 | 13 | -- | | | | | | 3 | Documents intended to | | | | | | be preserved longer | | | | | | than ten years-- | | | | | | | | | | | | (_a_) Foolscap paper | 2 | 3 | 33 × 42 | 13 | -- | | | | | | | Letter paper | | | | | | (quarto size) | 2 | 3 | 26·5 × 42 | 10·4 | -- | | | | | | | Letter paper | | | | | | (octavo size) | 2 | 3 | 26·5 × 21 | 5·2 | -- | | | | | | | Duplicating | | | | | | paper | 2 | 3 | 33 × 42 | 7 | -- | | | | | | | (_b_) Official | | | | | | writing paper | 2 | 4 | 33 × 42 | 13 | -- | | | | | | 4 | Paper for documents of| | | | | | lesser importance-- | | | | | | | | | | | | (_a_) Foolscap paper | 3 | -- | 33 × 42 | 12 | -- | | | | | | | Letter paper | | | | | | (quarto size) | 3 | -- | 26·5 × 42 | 9·6 | -- | | | | | | | Letter paper | | | | | | (octavo size) | 3 | -- | 26·5 × 21 | 4·8 | -- | | | | | | | (_b_) Official | | | | | | writing paper | 3 | 4 | 33 × 42 | 12 | -- | | | | | | 5 | Envelopes and | | | | | | wrappers-- | | | | | | | | | | | | (_a_) First quality | -- | 3 | -- | -- | -- | | | | | | | (_b_) Second quality | -- | 5 | -- | -- | -- | | | | | | 6 | Writing paper of | | | | | | medium quality | -- | 5-6 | -- | -- | -- | | | | | | 7 | Covers for documents--| | | | | | | | | | | | (_a_) That required | | | | | | for frequent use| 1 | Tearing | 36 × 47 | 81·2 | 480 | | | length | | | | | | 2,500 | | | | | |Elasticity| | | | | | 3·5% | | | | | | | | | | (_b_) For other | | | | | | purposes | 3 | Tearing | 36 × 47 | 42·3 | 250 | | | length | | | | | | 2,500 | | | | | |Elasticity| | | | | | 2·5% | | | | | | | | | 8 | Printing paper-- | | | | | | | | | | | | (_a_) For important | | | | | | printed matter | 1 | 4 | -- | -- | -- | | | | | | | (_b_) For less | | | | | | important | | | | | | printed matter | 3 | 4 | -- | -- | -- | | | | | | | (_c_) For common use | -- | 5-6 | -- | -- | -- --+-----------------------+------+----------+-----------+-------+------- CHAPTER XIII BIBLIOGRAPHY ANALYSIS, TECHNOLOGY, ETC. 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LACROIX, A.--Historique de la papeterie d'Angoulême suivi d'observations sur le commerce de chiffons en France. _Paris_, 8^o, 1863. LALANDE, J. J. LE F. DE.--L'art de faire le papier. Acad. Roy. des sciences. Description des Arts et Métiers, vol. 1. Fol., 1761. LETTRE sur les découvertes de M. Didot aîné dans les arts de ... la papeterie (l'invention du papier-vélin). _Paris_, 12^o, 1783. LEUCHS, J. C.--Beschreibung der in den letzten acht Jahren in der Papierfabrikation gemachten Verbesserungen. Nachtrag. _Nürnberg_, 8^o, 1828. MARABINI.--Bayrische Papiergeschichte. 1 Teil. Die Papiermühlen im Gebiete der weiland freien Reichsstadt Nürnberg. _Nürnberg_, 1894. MAUREL, F.--Le papier japonais. Histoire et fabrication d'après les documents Anglais et indigènes (excerpt). _Paris_, 4^o, 1871. MEERMAN, G., AND OTHERS.--Epistolæ, etc., de chartæ vulgaris lineæ origine. Ed. J. Van Vassen, Hagæ Com. Sm. 8^o, 1767. MIDOUX, E., AND MATTON, A.--Étude sur les filigranes des papiers employés en France aux 14^e et 15^e siècles. _Paris_, 8^o, 1868. MILLAR, O.--Papier-Industrie. Schweizerische Landesausstellung, 1883. Berichte, Gruppe 8, 1884. MURRAY, J.--Practical Remarks on Modern Paper, etc., with an Introductory Account of its Former Substitute. _Edinburgh_, 8^o, 1829. PARLATORE, P.--Mémoire sur le papyrus des Anciens et sur le papyrus de Sicile, Acad. des Sciences. Paris. Mèm. par divers Savans.... 2^e Serie, Tome 12. 4^o, 1854. PEIGNOT, E. G.--Essai sur l'histoire du parchemin et du vélin. _Paris_, 8^o, 1812. PENIG.--(Patentpapierfabrik zu Penig.) Ein Beitrag z. Geschichte d. Papiers, 1897. ROBERT, N. L.--Le centenaire de la machine a papier continu. Son invention par N. L. Robert en 1799. Biographie de l'inventeur, par J. Breville. Historique des divers perfectionnements ... par Didot Saint-Leger, 1800-1818. _Paris_, 8^o, 1901. ROBERTSON.--Fifty Years' Experience in Paper-making. _Leith._ SCHAEFFER, J. C.--Proefnemingen en Monster-Bladen om Papier te maaken zonder Lumpen of met een gering Byvoegzel derzelven. Uit het Hoogduits vertaald. Deel 1-2. _Amsterdam_, 2 vols., sm. 4^o, 1770. SCHAEFFER, J. C.--Sämtliche Papierversuche, 2te Aufl. Nebst 81 Mustern und 13 Kupfertafeln. _Regensburg_, 6 vols. in one, sm. 4^o, 1772. SCHAEFFER, J. C.--Erweis in Musterbogen dass die neuen Papierarten ... sich allerdings auch zu Tapeten übermahlen und gebrauchen lassen. _Regensburg_, fol. SMITH, J. E. A.--History of Paper, Genesis and Revelations. _Holyoke, Mass., U.S.A._, 1882. SOTHEBY, S. L.--The Typography of the 15th Century ... Exemplified in a Collection of Facsimiles from 100 Works, with their Watermarks. _London_, fol. 1845. SOTHEBY, S. L.--Principia Typographica. An Attempt to Elucidate the Paper Marks of the Period. _London_, 3 vols., fol. 1858. SPECHTHAUSEN.--Hundert Jahre der Papierfabrik Spechthausen. 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WEBER, R.--Papier-Industrie. Vienna Universal Exhibition, 1873. WEHRS, G. F.--Vom Papier, den vor der Erfindung desselben üblich gewesenen Schreibmassen und sonstigen Schreibmaterialien. _Halle_, 8^o, 1789. WINKLER, O.--Der Papierkenner. 1887. PAPER, SPECIAL KINDS. ANDÉS, L. E.--Papier-Spezialitäten, praktische Anleitung zur Herstellung. 1896. ANDÉS, L. E.--Treatment of Paper for Special Purposes. Translated from German. 1907. ANDÉS, L. E.--Die Fabrikation der Papiermaché und Papierstoff-Waren. _Leipzig_, 1900. ANDÉS, L. E.--Blattmetalle, Bronzen und Metallpapiere, deren Herstellung und Anwendung. _Wien_, sm. 8^o, 1902. BOECK, J. P.--Die Marmorirkunst für Buchbindereien, Buntpapierfabriken. _Wien_, sm. 8^o, 1880. BRIQUET, M.--De quelques industries nouvelles dont le papier est la base. _Genève_, 1885. EXNER, W. F.--Tapeten- und Buntpapier-Industrie. Paris Univ. Exhibition, 1867. Austrian Comm. Berichte. Heft 8. 1867. EXNER, W. F.--Tapeten- und Buntpapier. Vienna Universal Exhibition, 1873. Officieller Ausstellungs-Bericht. Heft 53. 8^o, 1873. FICHTENBERG.--Nouveau manuel complet du fabricant de papiers de fantaisie, papiers marbrés, etc. _Paris_, 18^o, 1852. HERRING, R.--Guide to Varieties and Value of Paper. 1860. HOFMANN, A. W.--Report on Vegetable Parchment (Gaine's Patent, No. 2834 of 1853). _London_, 8^o, 1858. KAEPPELIN, D.--Fabrication des papiers peints. Lacroix E., Études sur l'exposition de 1867. Vol. 1. 8^o, 1867. KAEPPELIN, D.--Fabrication des papiers peints. 1881. LINDSEY, G.--Pens and Papiermaché. Bevan, G. P., Brit. Manufacturing Industries (iii.). 12^o, 1876. MORTON, G. H.--The History of Paper-hangings, with Review of other Modes of Mural Decoration. _Liverpool_, 8^o, 1875. SANBORN, K.--Old Time Wall Papers. 1905. SCHMIDT, C. H.--Die Benutzung des Papiermaché. _Weimar_, 12^o, 1847. SCHMIDT, C. H.--Die Papier-Tapetenfabrikation. 3te Aufl. _Weimar_, 12^o, 1856. SCHMIDT, C. H.--The Book of Papiermaché and Japanning. _London_, 1850. SEEMAN, TH.--Die Tapete, ihre aesthetische Bedeutung u. Techn. Darstellung, sowie kurze Beschreibung der Buntpapierfabrik. 1882. SILCOX.--Manufacture of Paper Barrels. Vienna Exhibition, 1873. U.S.A. Reports, ii. SMEE, A.--Report on Vegetable Parchment (Gaine's Patent, No. 2834 of 1853). _London_, 8^o, 1858. THON, C. F. G.--Der Fabrikant bunter Papiere, 3te Aufl. _Weimar_, 12^o, 1844. WEICHELT, A.--Buntpapier-Fabrikation. _Berlin_, 8^o, 1903. WHITING PAPER CO.--How Paper is Made. _Holyoke, Mass._, 32^o, 1893. WINZER, A.--Die Bereitung und Benutzung der Papiermaché und ähnlicher Kompositionen, 3te Aufl. _Weimar_, 12^o, 1884. Ditto, 4th edition, 1907. WOOLNOUGH, C. W.--The Whole Art of Marbling, as applied to Paper, Book Edges, etc. _London_, 8^o, 1881. WYATT, SIR M. D.--Report on Paper-hangings. Paris Univ. Exhibition, 1867. Brit. Comm. Report, Vol. II. 8^o, 1867. STATISTICS AND VARIOUS. AKESSON.--Lexikon der Papier-Industrie. Deutsch-Englisch-Französisch, 2te Aufl. 1905. ARCHER, T. C.--British Manufacturing Industries. Vol. 15. Industrial Statistics. _London._ BARTH, E.--Arbeitsregeln für Fabriken mit besonderer Berücksichtigung von Papierfabriken. _Karlsruhe_, 1897. BAUDISCH, J.--Einige ins Papierfach schlagende Berechnungen. _Biberach_, 1893. DYSON.--Mosely Commission Report. _Manchester_, 1903. ERMEL.--Rapport sur le matériel et les procédés de la papeterie, etc. Paris Univ. Exhibition, 1878. Rapports. Classe 60. 8^o, 1881. FOREIGN OFFICE, No. 4 (1871).--Reports on the Manufacture of Paper in Japan. _London_, fol., 1871. GEYER, A.--Registry of Water-marks and Trade-marks. Compiled from the American Paper Trade (2nd edition). _New York_, 1898. Ditto, 5th edition, 1903. GRATIOT, A.--Description de la papeterie d'Essonnes, London International Exhibition of 1851, Prospectuses of Exhibitors. Vol. 2. 8^o, 1851. KRAWANY, F.--Warte der Papier-Halbstoff- und Pappenfabriken Oesterreich-Ungarns. 1905. LANDGRAF, J.--Papier-Holzschliff und seine Zollpolitische Würdigung. _Mannheim._ LOCKWOOD & CO.--American Dictionary of Printing and Bookmaking. _New York_, 1895. LUDWIG, G.--Trockengehalts-Tabellen. _Pirna_, 1897. MACNAUGHTON, J.--Factory Book-keeping for Paper Mills. 1900. MAHRLEN.--Papierfabrikation, im Königr. Württemberg (im Jahre 1860). _Stuttgart_, 8^o, 1861. MARR, D.--Kosten der Betriebskräfte bei 1-24 stündiger Arbeitszeit täglich und unter Berücksichtigung des Aufwandes für die Heizung. _München_ u. _Berlin_. MELNIKOFF, N.--Lehrbuch der Papier-Holzschliff, Zellstoff und Pappenfabrikation. _Petersburg_, 1905. MELNIKOFF, N.--Kleines Handbuch Papierfabrikation. _Petersburg_, 1906. MELNIKOFF, N.--Geschichte, Statistik u. Literatur der Papierindustrie nebst russischen Wasserzeichen. _Petersburg_, 1906. MUNSELL, J.--Chronology of Paper-making. _Albany_, 8^o, 1857. Ditto, 4th edition, 1870. MUNSELL, J.--Chronology of the Origin and Progress of Paper and Paper-making. _Albany_, 1876. MUNSELL, J.--Observations Illustrative of the Operation of the Duties on Paper. _London_, 8^o, 1836. MUNSELL, J.--Matériel et procédés de la papeterie, etc., 1889. Rapports du Jury. Classe 58. 8^o, 1889. PARIS UNIV. EXHIBITION.--Papiers peints, 1889. Rapports du Jury. Classe 21. 8^o, 1891. PASSERAT, A. L.--Barème complet pour papeteries. _Paris._ PATENTS.--Patent Abridgments. Class 96. Patent Office Abstracts on Paper-making. From 1855 to date. ROULHAC.--Papeterie. Paris Univ. Exhibition, 1867. Rapports du Jury. Classe 7, sect. 1. 8^o, 1868. SAMPSON, J. T.--Paper-staining. Mansion House Committee. Artisans' Reports, Paris Exhibition. 8^o, 1889. TREASURY.--Report of the Excise Commission. 1835. VOGEL, K.--Papierindustrie, etc., Auf der Weltausstellung in Chicago. Chicago Exhibition, 1893. Austrian Central Committee. Officieller Bericht. Heft iv. 8^o, 1894. VOIGT, G.--Papiergewichtstabellen. _Merseburg_, 1894. WARD, SIR W.--Report on German Paper-making Industry. Parliamentary Paper, 1905. WATER-MARKS.--Water-marks and Trade-marks Registry (2nd ed.). _New York_, 16^o, 1898. WOOD PULP AND PULP WOOD. BRITISH AND COLONIAL PRINTER.--History of Wood Pulp. Vol. 8. 1882. DUNBAR.--Wood Pulp and Wood Pulp Papers. FITTICA, DR. F.--Geschichte der Sulfitzellstoff-Fabrikation. _Leipzig_, 1901. FITTICA, DR. F.--Forestry and Forest Products. [Edinburgh Forestry Exhibition. 1884.] GOTTSTEIN.--Holzzellstoff in seiner Anwendung für die Papier- und Textil-Industrie und die bei seiner Herstellung entstehenden Abwässer. 1904. GRIFFIN, M. L.--Sulphite Processes. American Society C. E. 417. 1889. HARPER, W.--Utilisation of Wood Waste by Distillation. _U.S.A._, 1907. HARPF, A.--Die Erzeugung von Holzschliff und Zellstoff. _Wien_, 1901. HARPF, A.--Flüssiges Schwefeldioxyd. _Stuttgart_, 1901. HUBBARD.--Utilisation of Wood Waste. 1902. JOHNSON, G.--Wood Pulp of Canada. 1902-08. Yearly. MICHAELIS, O. E.--Lime Sulphite Fibre Manufacture in the United States. With Remarks on the Chemistry of the Processes, by M. L. Griffin (excerpt). _New York_, 8^o, 1889. PHILLIPS, S. C.--Uses of Wood Pulp. 1904. ROSENHEIM, G. M.--Die Holzcellulose. _Berlin_, 1878. SCHUBERT, M.--Die Holzstoff oder Holzschliff-Fabrikation. 1898. SCHUBERT, M.--Die Cellulosefabrikation (Zellstofffabrikation). Praktisches Handbuch für Papier- u. Cellulosetechniker. 1906. SINDALL, R. W.--The Sampling of Wood Pulp. _London_, 8^o, 1901. VEITCH, L. P.--Chemical Methods for Utilising Wood. U.S.A. Department of Agriculture. 1907. VEITCH, L. P.--Wood Pulp, Uses of. U.S.A. Consular Reports, vol. xix. * * * * * BANKS AND CRATE.--Pulpwood Problems. Letters to the _Globe_, Toronto, Canada. 1907. GAMBLE, J.--Indian Timbers. GRAVES.--The Woodsman's Handbook. _U.S.A._ PINCHOTT, G.--Forestry Primer. _U.S.A._, 1900. PINCHOTT, G.--The Adirondack Spruce. _U.S.A._ RATTRAY, J., AND MILL, H. R.--Forestry and Forestry Products. _Edinburgh_, 1885. SCHLICH.--Forestry Manual. * * * * * Some more or less interesting articles on "Paper" will be found in the following encyclopædias, etc.:-- DATE. 1738. Chambers's Encyclopædia. 1757. Barrow. Dictionary of Arts. 1759. New. Universal History of Arts. 1770. Royal Dictionary of Arts. 1788. Howard. A Royal Encyclopædia. 1806. Gregory. A Dictionary of Arts and Sciences. 1807. Encyclopædia Perthensis. 1809. Nicholson. The British Encyclopædia. 1813. Martin. Circle of the Mechanical Arts. 1813. Pantologia. 1819. Rees' Cyclopædia. 1821. Encyclopædia Londoniensis. 1827. Jamieson's Dictionary. 1828. Oxford Encyclopædia. 1829. The London Encyclopædia. 1830. Edinburgh Encyclopædia. 1833. Phillip's Dictionary of Arts. 1835. Partington. British Cyclopædia. 1836. Archæologia, vol. xxvi. 1836. Barlow. Encyclopædia of Arts. 1840. The Penny Encyclopædia. 1845. Encyclopædia Metropolitana. 1848. Useful Arts of Great Britain. S.P.C.K 1851. Knight's Cyclopædia of Industry. 1855. Appleton's Dictionary of Mechanics. 1860. Hebert. Mechanic's Encyclopædia. 1861. Knight's English Cyclopædia. 1861. New American Cyclopædia. 1866. Tomlinson's Dictionary of Arts. 1871. Yeats. The Technical History of Commerce. 1874. Clarke's Practical Magazine. 1875. Ure's Dictionary of Arts. 1875. Globe Cyclopædia. 1876. American Mechanical Dictionary. 1877. Johnson's Universal Cyclopædia. 1880. Wylde. Industries of the World. 1882. Spon's Encyclopædia of Manufactures. 1886. Encyclopædia Britannica. 1889. Chambers's Encyclopædia. 1889. Blaikie. Modern Cyclopædia. 1890. Popular Encyclopædia. 1892. Spon's Workshop Receipts. 1903. Gilman. International Encyclopædia. 1904. Encyclopædia Americana. 1904. Tweney's Technological Dictionary. NEWSPAPERS. _England._ Papermaker and British Paper Trade Journal. S. C. Phillips, London. Papermakers' Circular. Dean & Son, London. Papermakers' Monthly Journal. Marchant, Singer & Co., London. Paper Box and Bag Maker. S. C. Phillips, London. Papermaking. London. The Paper and Printing Trades' Journal. London. World's Paper Trade Review. W. J. Stonhill, London. _Canada._ Pulp and Paper Magazine. Biggar-Wilson, Ltd., Toronto. _United States of America._ American Bookmaker. Howard Lockwood & Co., New York. The Paper Trade. Chicago. The Stationer. Howard Lockwood & Co., New York. Paper Mill and Wood Pulp News. L. D. Post & Co., New York. Paper Trade Journal. Howard Lockwood & Co., New York. The Paper World. C. W. Bryan & Co., Holyoke, Mass. _France._ Bulletin Journal des Fabricants de Papier. Paris. Journal des Papetiers. M. Edmond Rousset, Paris. Le Moniteur de la Papeterie Française. Paris. La Papeterie. Paris. La Revue de la Papeterie Française et Étrangère. M. Edmond Rousset, Paris. Le Papier. H. Everling, Paris. _Germany._ Centralblatt für die Österreichisch-Ungarische Papierindustrie. Adolf Hladufka, Wien. Der Papierfabrikant. Otto Elsner, Berlin. Der Papier-Markt. Carl Dobler, Frankfurt a. Main. Deutsche Papier- und Schreibwarenzeitung. S. Richter, Berlin. Die Postkarte. Gustav Fahrig, Leipzig. Export-Journal. G. Hedeler, Leipzig. Holzstoff-Zeitung. Camillo Drache, Dresden. Papierhändler Zeitung für Österreich-Ungarn. Wien. Papier-Industrie. Berlin. Papier- und Schreibwaren-Zeitung. Wien. Papier-Zeitung. C. Hofmann, Berlin. Schweizer Graphischer Central-Anzeiger. H. Keller, Luzern. Wochenblatt für Papierfabrikation. Guntter-Staib Biberach (Württ). Wochenschrift für den Papier- und Schreibwarenhandel. Dr. H. Hirschberg, Berlin. ANALYSIS, TECHNOLOGY. BEADLE AND STEVENS.--Blotting paper, nature of absorbency. 1905. WINKLER.--Estimation of Moisture in Wood-pulp. 1902. Translated by Dr. H. P. Stevens. HAUPTVERSAMMLUNG.--Published annually by the Verein der Zellstoff- und Papier-Chemiker. _Berlin_, 1907 et. FIBRES, etc. DODGE, C. R.--Catalogue of useful Fibre-plants of the World. Report No. 9. Dept. of Agriculture. _U.S.A._, 1897. DUCHESNE, E. A.--Répertoire des plantes utiles et des plantes vénéneuses du globe, etc. _Bruxelles_, 1846. GABALDE, B.--Essai sur le bananier et ses applications à la fabrication de papier. 1843. MONTESSUS DE BALLORE.--Alfa et papier d'Alfa. 1908. PECHEUX.--Les textiles, les tissus, le papier. 6 pp. _Paris_, 1907. RENOUARD.--Études sur les fibres textiles. _Paris._ RENOUARD.--Les fibres textiles de l'Algérie. _Paris._ RIVIERE, AUGUSTE ET CHARLES.--"Les Bambous." Société d'Acclimatation. _Paris._ RICHMOND, G. F.--Philippine Fibres and Fibrous Substances. _Manila_, Bureau of Printing, 1906. HISTORICAL. BRIQUET, C. M.--Recherches sur les premiers Papiers employés du X^e au XIV^e siècle. pp. 77. _Paris_, 1886. BRIQUET, C. M.--De la valeur des Filigranes du Papier comme moyen de déterminer l'âge de documents. pp. 13. _Genève_, 1892. BRIQUET, C. M.--La Légende paléographique du Papier de Coton. pp. 18. _Genève_, 1884. BRIQUET, C. M.--Lettre sur les Papiers usités en Sicile à l'occasion de deux manuscrits en papier dit le coton. 16 pp. _Palermo_, 1892. DESMAREST, N.--Art de la Papeterie. _Paris_, 1879. DELON, C.--Histoire d'un livre. _Paris_, 1879. DIDOT, A. F.--Le centenaire de la Machine à Papier continu. pp. 79. _Paris_, 1900. DICKINSON, J.--Dickinson's Paper Mills. _Calcutta_, 1884. GIRARD, A.--Le Papier. Ses ancêtres. Son histoire. _Lille_, 1892. JULIEN, S.--Description des procédés chinois pour la fabrication du papier. Traduit de l'ouvrage chinois par Thien-Kong-Kha-We. 1840. KAY, J.--Paper, its history. pp. 100. _London_, 1893. LEMPERTZ, H.--Beiträge zur Geschichte des Leinen-Papiers. _Köln_, 1891. PAPER MANUFACTURE. BORY, P.--Les Métamorphoses d'un Chiffon. _Abbeville_, 1897. CHABROL, L.--La Réglementation du Travail dans l'industrie du papier. pp. 168. _Paris_, 1901. DEMUTH, F.--Die Papier-Fabrikation. 1903. DEMUTH, F.--Die Störungen im deutschen Wirtschaftsleben 1900. _Leipzig_, 1903. LIMOGE.--Cercles d'Études commerciales, Le Papier. pp. 140. _Limoge_, 1892. PAPER, SPECIAL KINDS. SPALDING AND HODGE.--Printing papers; a handbook. _London_, 1905. STATISTICS, etc. BEADLE, C.--Development of Water-marking. _London_, 1906 (Society of Arts). DUMERCY.--Bibliographie de la Papeterie. pp. 28. _Bruxelles_, 1888. BRUCE, H.--Gladstone and Paper Duties. _Edinburgh_, 1885. ELLIS, J. B.--Hints for the Paper Warehouse. _Leeds_, 1887. WEBSTER, J.--Synopsis of Sizes of Paper. _Southport_, 1889. WHITSON, W.--The Concise Paper Calculator. _Edinburgh_, 1903. WOOD PULP, etc. DROPISCH, B.--Holzstoff und Holzcellulose. _Weimar_, 1879. INDEX Acid dyes, 201 in papers, 239 size, 170 Agave, 40 Alum, 167, 168 Aniline dyes, 201 sulphate, 121 Animal size, 63, 164 Antichlors, 163 Art paper, 142 imitation, 145 testing, 147 Asbestos, 174 Ash in paper, 171 Backwater, 120, 205 Bagasse, 41 Bamboo, 43 Barker, 97 Beating engines, 186 patents, 192 power consumed, 191 Beating, conditions of, 197 early methods of, 176 experiments in, 179 process of, 58, 175 Bibliography, 253 Bisulphite of lime, 159 Bleaching, 57, 83 powder, 161 Blue prints, 140 Board machine, 132, 135 Boards, manufacture of, 131 duplex, 132, 134 Book papers, quality of, 246 Books, decay of, 237 Brown papers, 127 Carbonic acid recorder, 215 Casein, 165, 235 Caustic soda, 81, 155 Cellulose, 21 derivatives of, 29 hydrolysis of, 27, 229 oxidation of, 28 percentage of, in plants, 23 properties of, 26 Chemical residues in paper, 238 wood pulp, 104 Chemicals, 153 China clay, 117, 150, 171, 204, 234 Coal consumption, 214 Coated paper, 142 Cold ground pulp, 100 Colophony, 169 Colour of paper, fading of, 203, 241 matching, 205 unevenness of, 203 Colouring of paper pulp, 199 analysis of, 206 Cotton, 22, 69 Cyanotype papers, 140 Cylinder machine, 131 Density of paper, 181 Deterioration of paper, 228, 246 Digesters, 52, 89, 109 Dilution tables, 157, 163 Duplex boards, 134 Dyeing of paper, 199 Eibel patent, 223 Electrical power, 219 Electrolytic bleaching, 57 Engine sizing, 117, 167 Esparto, 72 bleaching of, 83 composition of, 73 test for, in papers, 87 yield of, 77 Evaporation apparatus, 76, 79 tables, 81 Featherweight papers, 232 Fibres for paper-making, 38 examination of, 43 reagents for staining, 71 Flax, 40 Fourdrinier machine, early, 16 French chalk, 173 Gas producer, 218 Gelatine, 63, 164, 237 Glue, 137, 142, 235 Grinders, 100 History of paper, 1 Hoernle, 7 Hollander, 16, 59, 176, 185 Hot ground pulp, 100 Imitation art paper, 145, 235 Kraft paper, 129 parchment, 137 Improvements in paper-making, 214 Iron in paper, 229 Kraft papers, 128 Laid papers, 66 Lime, 52, 157 bisulphite, 159 sulphate, 173 Linen fibre, 70 Loading, 171 M. G. caps, 130 Machinery, 214, 224 Manila paper, 127 Mechanical pulp, 95 detection of, 121 Metanil yellow, 122 Middles, 134 Mitscherlich pulp, 107 Moisture, influence of, 243 Multiple effect evaporation, 79 Neutral size, 169 Newspaper, 116, 215 Output of a paper machine, 122 Paper, art, 142 ash in, 171 brown, 127 bulk of, 231 chemical residues in, 238 clay in, 234 colour of, 199, 241 colour in, analysis of, 207 deterioration of, 229 fibres for, 38 history of, 1, 5 iron in, 239 permanence of, 230 rags used for, 47 sizing of, 63 special kinds of, 137 standards of quality, 246 strength, of, 184, 231 surface of, 233 volume composition of, 233 Paper machine, early, 16 output of, 122 Papier-maché, 150 Papyrus, 2, 42 Paraffin paper, 148 Parchment, 4 paper, 137 Peat, 41 Phloroglucine, 121 Pigments, 199 Porion evaporator, 76 Presse-pâte, 86 Prussian blue, 200 Rag paper, manufacture of, 47 origin of, 5 Rags, bleaching, 55 boiling, 51 classification, 48 sorting, 48 Ramie, 40 Records, early, 1 Recovered ash, 158 Recovery processes, 78, 113 Refiners, 90 Rope browns, 127 Rosin size, 117, 169, 236 Screens, 102 Sealings, 129 Shrinkage of paper, 181 Sizing of paper, 63, 117, 167 Society of Arts, 246 Soda, 153 Soda pulp, 107, 113 recovery, 78 silicate of, 166, 171 Softening of water, 216 Spent liquors, 78, 113 Staining reagents for fibres, 71 Standards of quality, 246, 248, 250 Starch, 166, 237 Stationery Office, 248 Stone beater rolls, 189 Straw, 88 Sulphate pulp, 107 Sulphite pulp, 107 Sulphites, 159, 163 Supercalender, 65 Superheated steam, 218 Tinfoil paper, 148 Transfer paper, 149 Ultramarine, 199 Volume composition of paper, 233 Vulcanised fibre, 139 Water softening, 216 Watermarks, 67 Wavy edges, 243 Waxed paper, 147 Wet press machine, 103 Wiesner, 6 Willesden paper, 139 Wood, 22 pulp, 95 chemical, 104 mechanical, 95 soda, 107, 113 sulphite, 107 Wove papers, 66 Wrappers, 127 BRADBURY, AGNEW, & CO. LD., PRINTERS, LONDON AND TONBRIDGE. VAN NOSTRAND'S "Westminster" Series Bound in uniform style. Fully Illustrated. Price $2·00 net each. The Volumes in the _"Westminster" Series_ have been designed to meet the growing demand for books on practical subjects; to bring within the ken of the non-technical reader an accurate knowledge of manufacturing processes and the practical application of modern science to industries. Each volume is written by an expert to the end that practical readers and all who are engaged in the numerous allied branches of the engineering and technical trades may have reliable works of reference. The series provides for a class not hitherto reached in published works. The volumes can be easily read by the general public, and make excellent handbooks at a moderate price for the student. The series is well suited to public libraries and will be found valuable for libraries in engineering shops and factories. D. VAN NOSTRAND COMPANY _Publishers and Booksellers_ 23, Murray and 27, Warren Streets, New York. $Coal.$ By JAMES TONGE, M.I.M.E., F.G.S., etc. (Lecturer on Mining at Victoria University, Manchester). With 46 Illustrations, many of them showing the Fossils found in the Coal Measures. LIST OF CONTENTS: History. Occurrence. Mode of Formation of Coal Seams. Fossils of the Coal Measures. Botany of the Coal-Measure Plants. Coalfields of the British Isles. Foreign Coalfields. The Classification of Coals. The Valuation of Coal. Foreign Coals and their Values. Uses of Coal. The Production of Heat from Coal. Waste of Coal. The Preparation of Coal for the Market. Coaling Stations of the World. Index. This book on a momentous subject is provided for the general reader who wishes accurate knowledge of Coal, its origin, position and extent, and its economical utilization and application. $Iron and Steel.$ By J. H. STANSBIE, B.Sc. (Lond.), F.I.C. With 86 Illustrations. LIST OF CONTENTS: Introductory. Iron Ores. Combustible and other materials used in Iron and Steel Manufacture. Primitive Methods of Iron and Steel Production. Pig Iron and its Manufacture. The Refining of Pig Iron in Small Charges. Crucible and Weld Steel. The Bessemer Process. The Open Hearth Process. Mechanical Treatment of Iron and Steel. Physical and Mechanical Properties of Iron and Steel. Iron and Steel under the Microscope. Heat Treatment of Iron and Steel. Electric Smelting. Special Steels. Index. The aim of this book is to give a comprehensive view of the modern aspects of iron and steel, together with a sufficient account of its history to enable the reader to follow its march of progress. The methods of producing varieties of the metal suitable to the requirements of the engineer, foundryman and mechanician are described so that the worker may learn the history of the material he is handling. $Natural Sources of Power.$ By $Robert S. Ball$, B.Sc., A.M.Inst.C.E. With 104 Diagrams and Illustrations. CONTENTS: Preface. Units with Metric Equivalents and Abbreviations. Length and Distance. Surface and Area. Volumes. Weights or Measures. Pressures. Linear Velocities, Angular Velocities. Acceleration. Energy. Power. Introductory Water Power and Methods of Measuring. Application of Water Power to the Propulsion of Machinery. The Hydraulic Turbine. Various Types of Turbine. Construction of Water Power Plants. Water Power Installations. The Regulation of Turbines. Wind Pressure, Velocity, and Methods of Measuring. The Application of Wind Power to Industry. The Modern Windmill. Constructional Details. Power of Modern Windmills. Appendices A, B, C. Index. Two departments of Engineering and their applications to industry form the subject of this volume: the "natural" sources of water and wind power which supply mechanical energy without any intermediate stage of transformation. Most people will be surprised at the extent to which these natural power producers are used. The widespread application of water power is generally known, but it is interesting to learn that the demand for windmills was never so great as it is to-day, and there are signs of abnormal expansion in the direction of their useful application in the great agricultural countries of the world. Though primarily of importance to the engineer, this work will be of great interest to every manufacturer who in economizing his means of power production can take the natural forces that lie to his hand and harness them in his service. The author is the son of Sir Robert Ball, the eminent mathematician and astronomer. $Liquid and Gaseous Fuels, and the Part they play in Modern Power Production.$ By Professor VIVIAN B. LEWES, F.I.C., F.C.S., Prof. of Chemistry, Royal Naval College, Greenwich. With 54 Illustrations. LIST OF CONTENTS: Lavoisier's Discovery of the Nature of Combustion, etc. The Cycle of Animal and Vegetable Life. Method of determining Calorific Value. The Discovery of Petroleum in America. Oil Lamps, etc. The History of Coal Gas. Calorific Value of Coal Gas and its Constituents. The History of Water Gas. Incomplete Combustion. Comparison of the Thermal Values of our Fuels, etc. Appendix. Bibliography. Index. The subject of this book has, during the last decade, assumed such importance that it is hoped this account of the history and development of the use of various forms of combustible liquids and gases for the generation of energy may do some service in its advancement. $Electric Power and Traction.$ By F. H. DAVIES, A.M.I.E.E. With 66 Illustrations. LIST OF CONTENTS: Introduction. The Generation and Distribution of Power. The Electric Motor. The Application of Electric Power. Electric Power in Collieries. Electric Power in Engineering Workshops. Electric Power in Textile Factories. Electric Power in the Printing Trade. Electric Power at Sea. Electric Power on Canals. Electric Traction. The Overhead System and Track Work. 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Cooking by Gas. The Healthfulness and Safety of Gas in all its uses. Town Gas for Power Generation, including Private Electricity Supply. The Legal Relations of Gas Suppliers, Consumers, and the Public. Index. The "country," as opposed to the "town," has been defined as "the parts beyond the gas lamps." This book provides accurate knowledge regarding the manufacture and supply of town gas and its uses for domestic and industrial purposes. Few people realize the extent to which this great industry can be utilized. The author has produced a volume which will instruct and interest the generally well informed but not technically instructed reader. $Electro-Metallurgy.$ By J. B. C. KERSHAW, F.I.C. With 61 Illustrations. CONTENTS: Introduction and Historical Survey. Aluminium. Production. Details of Processes and Works. Costs. Utilization. Future of the Metal. Bullion and Gold. Silver Refining Process. Gold Refining Processes. Gold Extraction Processes. Calcium Carbide and Acetylene Gas. 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Dry Processes. Electro-Thermal Processes. Electro-Galvanizing. Glossary. Name Index. The subject of this volume, the branch of metallurgy which deals with the extraction and refining of metals by aid of electricity, is becoming of great importance. The author gives a brief and clear account of the industrial developments of electro-metallurgy, in language that can be understood by those whose acquaintance with either chemical or electrical science may be but slight. It is a thoroughly practical work descriptive of apparatus and processes, and commends itself to all practical men engaged, in metallurgical operations, as well as to business men, financiers, and investors. $Radio-Telegraphy.$ By C. C. F. MONCKTON, M.I.E.E. With 173 Diagrams and Illustrations. CONTENTS: Preface. Electric Phenomena. Electric Vibrations. Electro-Magnetic Waves. Modified Hertz Waves used in Radio-Telegraphy. Apparatus used for Charging the Oscillator. The Electric Oscillator: Methods of Arrangement, Practical Details. The Receiver: Methods of Arrangement, The Detecting Apparatus, and other details. Measurements in Radio-Telegraphy. The Experimental Station at Elmers End: Lodge-Muirhead System. Radio-Telegraph Station at Nauen: Telefunken System. Station at Lyngby: Poulsen System. The Lodge-Muirhead System, the Marconi System, Telefunken System, and Poulsen System. Portable Stations. Radio-Telephony. Appendices: The Morse Alphabet. Electrical Units used in this Book. International Control of Radio-Telegraphy. Index. The startling discovery twelve years ago of what is popularly known as Wireless Telegraphy has received many no less startling additions since then. The official name now given to this branch of electrical practice is Radio-Telegraphy. The subject has now reached a thoroughly practicable stage, and this book presents it in clear, concise form. The various services for which Radio-Telegraphy is or may be used are indicated by the author. Every stage of the subject is illustrated by diagrams or photographs of apparatus, so that, while an elementary knowledge of electricity is presupposed, the bearings of the subject can be grasped by every reader. No subject is fraught with so many possibilities of development for the future relationships of the peoples of the world. $India-Rubber and its Manufacture, with Chapters on Gutta-Percha and Balata.$ By H. L. TERRY, F.I.C., Assoc.Inst.M.M. With Illustrations. LIST OF CONTENTS: Preface. Introduction: Historical and General. Raw Rubber. Botanical Origin. Tapping the Trees. Coagulation. Principal Raw Rubbers of Commerce. Pseudo-Rubbers. Congo Rubber. General Considerations. Chemical and Physical Properties. Vulcanization. India-rubber Plantations. India-rubber Substitutes. Reclaimed Rubber. Washing and Drying of Raw Rubber. Compounding of Rubber. Rubber Solvents and their Recovery. Rubber Solution. Fine Cut Sheet and Articles made therefrom. Elastic Thread. Mechanical Rubber Goods. Sundry Rubber Articles. India-rubber Proofed Textures. Tyres. India-rubber Boots and Shoes. Rubber for Insulated Wires. Vulcanite Contracts for India-rubber Goods. The Testing of Rubber Goods. Gutta-Percha. Balata. Bibliography. Index. Tells all about a material which has grown immensely in commercial importance in recent years. It has been expressly written for the general reader and for the technologist in other branches of industry. $Glass Manufacture.$ By WALTER ROSENHAIN, Superintendent of the Department of Metallurgy in the National Physical Laboratory, late Scientific Adviser in the Glass Works of Messrs. Chance Bros. and Co. With Illustrations. CONTENTS: Preface. Definitions. Physical and Chemical Qualities. Mechanical, Thermal, and Electrical Properties. Transparency and Colour. Raw materials of manufacture. Crucibles and Furnaces for Fusion. Process of Fusion. Processes used in Working of Glass. Bottle. Blown and Pressed. Rolled or Plate. Sheet and Crown. Coloured. Optical Glass: Nature and Properties, Manufacture. Miscellaneous Products. Appendix. Bibliography of Glass Manufacture. Index. This volume is for users of glass, and makes no claim to be an adequate guide or help to those engaged in glass manufacture itself. For this reason the account of manufacturing processes has been kept as non-technical as possible. In describing each process the object in view has been to give an insight into the rationale of each step, so far as it is known or understood, from the point of view of principles and methods rather than as mere rule of thumb description of manufacturing manipulations. The processes described are, with the exception of those described as obsolete, to the author's definite knowledge, in commercial use at the present time. $Precious Stones.$ By W. GOODCHILD, M.B., B.Ch. With 42 Illustrations. $With a Chapter on Artificial Stones.$ By ROBERT DYKES. LIST OF CONTENTS: Introductory and Historical. Genesis of Precious Stones. Physical Properties. The Cutting and Polishing of Gems. Imitation Gems and the Artificial Production of Precious Stones. The Diamond. Fluor Spar and the Forms of Silica. Corundum, including Ruby and Sapphire. Spinel and Chrysoberyl. The Carbonates and the Felspars. The Pyroxene and Amphibole Groups. Beryl, Cordierite, Lapis Lazuli and the Garnets. Olivine, Topaz, Tourmaline and other Silicates. Phosphates, Sulphates, and Carbon Compounds. An admirable guide to a fascinating subject. $Patents, Designs and Trade Marks: The Law and Commercial Usage.$ By KENNETH R. SWAN, B.A. (Oxon.), of the Inner Temple, Barrister-at-Law. CONTENTS: Table of Cases Cited--_Part I.--Letters Patent._ Introduction. General. Historical. I., II., III. Invention, Novelty, Subject Matter, and Utility the Essentials of Patentable Invention. IV. Specification. V. Construction of Specification. VI. Who May Apply for a Patent. VII. Application and Grant. VIII. Opposition. IX. Patent Rights. Legal Value. Commercial Value. X. Amendment. XI. Infringement of Patent. XII. Action for Infringement. XIII. Action to Restrain Threats. XIV. Negotiation of Patents by Sale and Licence. XV. Limitations on Patent Right. XVI. Revocation. XVII. Prolongation. XVIII. Miscellaneous. XIX. Foreign Patents. XX. Foreign Patent Laws: United States of America. Germany. France. Table of Cost, etc., of Foreign Patents. APPENDIX A.--1. Table of Forms and Fees. 2. Cost of Obtaining a British Patent. 3. Convention Countries. _Part II.--Copyright in Design._ Introduction. I. Registrable Designs. II. Registration. III. Marking. IV. Infringement. APPENDIX B.--1. Table of Forms and Fees. 2. Classification of Goods. _Part III.--Trade Marks._ Introduction. I. Meaning of Trade Mark. II. Qualification for Registration. III. Restrictions on Registration. IV. Registration. V. Effect of Registration. VI. Miscellaneous. APPENDIX C.--Table of Forms and Fees. INDICES. 1. Patents. 2. Designs. 3. Trade Marks. This is the first book on the subject since the New Patents Act. Its aim is not only to present the existing law accurately and as fully as possible, but also to cast it in a form readily comprehensible to the layman unfamiliar with legal phraseology. It will be of value to those engaged in trades and industries where a knowledge of the patenting of inventions and the registration of trade marks is important. Full information is given regarding patents in foreign countries. $The Book; Its History and Development.$ By CYRIL DAVENPORT, V.D., F.S.A. With 7 Plates and 126 Figures in the text. LIST OF CONTENTS: Early Records. Rolls, Books and Book bindings. Paper. Printing. Illustrations. Miscellanea. Leathers. The Ornamentation of Leather Bookbindings without Gold. The Ornamentation of Leather Bookbindings with Gold, Bibliography. Index. The romance of the Book and its development from the rude inscriptions on stone to the magnificent de Luxe tomes of to-day have never been so excellently discoursed upon as in this volume. The history of the Book is the history of the preservation of human thought. This work should be in the possession of every book lover. Van Nostrand's "Westminster" Series LIST OF NEW AND FORTHCOMING VOLUMES. $Timber.$ By J. R. BATERDEN, A.M.I.C.E. $Steam Engines.$ By J. T. ROSSITER, M.I.E.E., A.M.I.M.E. $Electric Lamps.$ By MAURICE SOLOMON, A.C.G.I., A.M.I.E.E. $The Railway Locomotive.$ By VAUGHAN PENDRED, M.I.Mech.E. $Leather.$ By H. GARNER BENNETT. $Pumps and Pumping Machinery.$ By JAMES W. ROSSITER, A.M.I.M.E. $Workshop Practice.$ By Professor G. F. CHARNOCK, A.M.I.C.E., M.I.M.E. $Textiles and their Manufacture.$ By ALDRED BARKER, M.Sc. $Gold and Precious Metals.$ By THOMAS K. 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VAN NOSTRAND COMPANY _Publishers and Booksellers_ 23, MURRAY AND 27, WARREN STREETS, NEW YORK. +--------------------------------------------------------------------+ | Transcriber's Notes | | | | The following inconsistencies were kept: | | | | 500-K.W. -- 1000 K.W. | | back-water -- backwater | | bed-plate -- bedplate | | Buntpapier-Fabrikation -- Buntpapierfabrikation | | cc. -- c.c. | | coloration -- colouring | | conical-shaped -- conical shaped | | Cwts. -- cwts. | | Darthford (cited) -- Dartford | | drum washers -- drum-washer | | economiser -- economizing | | edge runner -- edge-runner | | gesamte -- gesammten | | grams -- grammes | | h.p. -- h.-p. | | Holzschliffes -- Holzschliffs | | Hydral-Cellulose -- hydra-cellulose | | India-Rubber -- India-rubber | | midfeather -- mid-feather | | Mitteilungen -- Mittheilungen | | oval shaped -- oval-shaped | | Oxy-Cellulose -- Oxy-cellulose | | oxy-cellulose -- oxycellulose | | Paper-maker -- Papermaker | | Papiererzeugung -- Papier-Erzeugung | | Papierfabrikation -- Papier-Fabrikation | | per cent. -- per Cent. | | realise -- realize | | Schreibwarenzeitung -- Schreibwaren-Zeitung | | sugarcane -- sugar-cane | | utilisation -- utilization | | utilised -- utilized | | Vulcanised -- Vulcanization | | Watermarks -- Water-marks | | workman -- work-woman | | | | The following changes have been made: | | | | p. iii "versâ" replaced by "versa" | | p. ix "PRESSE-PÀTE" replaced by "PRESSE-PÂTE" | | p. 10 "Kulturhistorischen" replaced by "Kulturhistorisches" | | (caption Fig. 2) | | p. 16 "Vollstandige Muhlen" replaced by "Vollständige Mühlen" | | p. 19 "couch-rolls" replaced by "couch rolls" | | p. 54 "back-fall" replaced by "backfall" | | p. 57 "Beaume" replaced by "Baumé" | | p. 84 "tes" replaced by "test" | | p. 141 "Beaume" replaced by "Baumé" | | p. 203 "lignocellulose" replaced by "ligno-cellulose" | | p. 210 "Ubersicht" replaced by "Übersicht" | | p. 226 "press-pâte" replaced by "presse-pâte" | | p. 238 "paper makers" replaced by "paper-makers" | | p. 256 "Andes" replaced by "Andés" | | p. 257 "Muller" replaced by "Müller" | | p. 259 "Hoessle" replaced by "Hössle" | | p. 260 "Paralatore" replaced by "Parlatore" | | p. 264 "Muller" replaced by "Müller" | | p. 267 "Bookbinding" replaced by "Bookmaking" | | p. 268 "Parish" replaced by "Paris" | | p. 253 - 272B Further 97 corrections in German, Dutch and French | | book titles without separate notices. | | (4) "Bye-Products" replaced by "By-Products" | | (7) "evey" replaced by "every" | | | | | +--------------------------------------------------------------------+