,a ,,text-,,book ,,of ,,paper-,,making2 ,,by ,c4 ,f4 ,,cross ,,and ,e4 ,j4 ,,bevan 7#ahhh7 ,illustration3 ,,cotton4 #ej4 ,,linen4 #ej4 ,,esparto4 #ej4 ,,mechanical ,,wood-,,pulp4 #ej4 ,,chemical ,,wood-,,pulp4 #ej4 ,a ,,text-,,book ,,of ,,paper-,,making4 ,,by ,c4 ,f4 ,,cross ,,and ,e4 ,j4 ,,bevan4 ,illustration ,e4 ,f4 ,n4 ,,spon1 #abe1 ,,strand1 ,,london4 ,,new ,,york3 #ce1 ,,murray ,,street4 #ahhh4 ,,preface4 ,the practical portion of the present work has in part already appeared as an article1 by one of the authors1 in #8,spons' ,encyclopdia of the ,industrial ,arts4' ,since its publication1 however1 many and important improvements have been introduced in this1 as in other branches of the art of paper-making1 which necessitated considerable additions to the original article4 ,it has at the same time been to a great extent re-written1 and1 as the authors hope1 improved4 ,our object in writing this book has been to bring before students and others the principles upon which scientific paper-making should be conducted1 a concise exposition of which has not1 we believe1 been hitherto attempted4 ,considerable prominence has been given to this aspect of the subject1 possibly at the expense of what some may consider more essential details4 ,a belief in the importance of a thorough scientific training for paper-makers has dictated the style and purpose of the book4 ,we have not thought it necessary to enter into minute details respecting the construction of machinery1 c42 for these the reader is referred to such works as ,hofmann's ,treatise on the ,manufacture of ,paper4 ,much of the scientific portion is here published for the first time4 ,part of it has already appeared in the form of papers read before various societies4 ,the chapter relating to the ,treatment of ,wood formed the subject of an essay1 which obtained the prize offered by the ,scottish ,paper-makers' ,association1 in connection with the ,edinburgh ,forestry ,exhibition1 #ahhd4 ,we would here express our obligations to ,messrs4 ,g4 and ,w4 ,bertram1 ,messrs4 ,masson1 ,scott1 and ,bertram1 ,messrs4 ,rckner and ,co41 and others1 for their courtesy in furnishing us with the drawings from which the illustrations were prepared2 to ,dr4 ,c4 ,r4 ,a4 ,wright1 ,f4,r4,s41 who kindly communicated the substance of the chapter on the ,action of ,cuprammonium on ,cellulose2 to ,mr4 ,carl ,christensen1 for drawings and information regarding the manufacture of mechanical wood-pulp2 also to the following friends1 among others1 who have1 in various ways1 rendered us important assistance3--,messrs4 ,r4 ,c4 ,menzies1 ,c4 ,m4 ,king1 ,g4 ,e4 ,davis1 ,a4 ,beckwith1 and ,c4 ,beadle4 ,finally1 we would tender our thanks to ,mr4 ,c4 ,g4 ,warnford ,lock for the care he has bestowed on the editing of the book4 ,the indexing and the ,chapter on ,statistics are entirely his production4 ,c4 ,f4 ,,cross and ,e4 ,j4 ,,bevan4 #d1 ,,new ,,court1 ,,lincoln',s-,,inn1 ,w4,c4 ,,contents4 ,,introductory ,,note 4 4 4 #a ,,chapter ,i4 ,,cellulose--,,the ,,chemical ,,properties ,,of ,,typical ,,members ,,of ,,the ,,cellulose ,,group1 ,,with ,,reference ,,to ,,their ,,natural ,,history 4 4 4 #d ,,chapter ,,ii4 ,,physical ,,structure ,,of ,,fibres--,,microscopical ,,examination 4 4 4 #cj ,,chapter ,,iii4 ,,chemical ,,analysis ,,of ,,plant ,,substances 4 4 4 #db ,,chapter ,,iv4 ,,an ,,account ,,of ,,the ,,chemical ,,and ,,physical ,,characteristics ,,of ,,the ,,principal ,,raw ,,materials 4 4 4 #df ,,chapter ,v4 ,,processes ,,for ,,isolating ,,cellulose ,,from ,,plant ,,substances 4 4 4 #fb ,,chapter ,,vi4 ,,special ,,treatment ,,of ,,various ,,fibres--,,boilers1 ,,boiling ,,processes1 ,c4 4 4 4 #gi ,,chapter ,,vii4 ,,bleaching 4 4 4 #aaj ,,chapter ,,viii4 ,,beating 4 4 4 #aag ,,chapter ,,ix4 ,,loading1 ,,sizing1 ,,colouring1 ,c4 4 4 4 #abg ,,chapter ,x4 ,,paper ,,machines1 ,,hand-,,made ,,paper 4 4 4 #add ,,chapter ,,xi4 ,,calendering1 ,,cutting1 ,c4 4 4 4 #afg ,,chapter ,,xii4 ,,caustic ,,soda1 ,,recovered ,,soda1 ,c4 4 4 4 #agg ,,chapter ,,xiii4 ,,the ,,testing ,,of ,,paper1 ,,mechanical1 ,,chemical1 ,,and ,,microscopical 4 4 4 #aic ,,chapter ,,xiv4 ,,general ,,chemical ,,analysis ,,for ,,paper-,,makers 4 4 4 #bje ,,chapter ,,xv4 ,,site ,,for ,,paper-,,mill--,,water ,,purification 4 4 4 #baj ,,chapter ,,xvi4 ,,action ,,of ,,cuprammonium ,,on ,,cellulose--,,willesden ,,paper 4 4 4 #bag ,,chapter ,,xvii4 ,,statistics 4 4 4 #bba ,,chapter ,,xviii4 ,,bibliography 4 4 4 #bbi ,,chapter ,,xix4 ,,addenda 4 4 4 #bca ,,index 4 4 4 #bcc #a ,,paper-,,making4 ,,introductory ,,note4 ,the raw materials of the paper-maker are primarily the vegetable fibrous substances2 in addition to these there are various articles which are employed as auxiliaries1 either in the preparatory or finishing processes to which these fibrous materials1 or the web of paper are subjected4 ,the latter class are of subsidiary importance1 more especially from our present point of view4 ,in insisting upon the recognition of first principles1 we cannot overrate the importance of a thorough grasp of the constitution of the plant fibres1 as the necessary foundation for the intelligent conduct of paper-making1 and to this subject we will at once proceed4 ,careful study of a mature plant will show that it is made up of structural elements of two kinds1 viz4 fibres and cells1 which1 to use a rough parallel1 we may liken in function to the bricks and mortar of a house4 ,it is the former which admit of the many extended uses1 with which we are familiar1 in the arts of spinning and weaving1 and which constitute the fabrics which are the most indispensable to our civilised life4 ,for the most part1 as we know1 fibres and cells are aggregated together into compound tissues1 and a process of separation is therefore a necessary preliminary to the utilisation of the former4 ,the cotton fibre is the only important exception to this general condition of distribution4 ,here we have the seed envelope or perisperm1 converted into a mass #b of fibres1 and these by a spontaneous process accompanying the ripening1 so isolated as to be immediately available4 ,next in order in point of simplicity of isolation1 are those fibrous masses1 or tissues1 which1 although components of complex structures1 exhibit a greater cohesion of their constituent fibres than adhesion to the contiguous cellular tissues with which they go to build up the plant4 ,into such a tissue the 8bast10 or inner bark layer of shrubs and trees1 more especially those of tropical and sub-tropical regions1 frequently develops1 and it is1 in fact1 this bast tissue1 graduating in respect of cohesion of its constituent fibres1 from a close network such as we have spoken of1 to a collection of individual fibres or fibre-bundles disposed in parallel series1 which supplies the greater part of the more valuable of the textile and paper-making fibres2 we may instance flax1 hemp1 and jute1 each of which is the basis of an enormous industry4 ,according to the degree of adhesion of the bast to the contiguous tissues1 or1 in another aspect1 according to its lesser aggregate development1 so is the difficulty of isolation and the necessity of using processes auxiliary to the mechanical separation of the tissue4 ,it is worthy of note here that the ,japanese paper with which we are in these times so familiar1 is prepared by the most primitive means from the bast of a mulberry 7,broussonetia papyrifera72 the isolated tissue1 consisting of a close network of fibres1 is simply cut and hammered to produce a surface of the requisite evenness1 and the production of a web of paper is complete4 ,in isolating the bast fibres employed in the textile industries1 a preliminary partial disintegration of the plant stem is brought about by the process of steeping or retting1 by which the separation of fibre from flesh or cellular tissue is much facilitated4 ,last in order of simplicity of distribution1 we have the fibres known to the botanist as the fibro-vascular bundles of leaves and monocotyledonous stems1 these bundles being irregularly distributed through the main cellular mass1 and consequently1 by reason of adhesion thereto1 much more #c difficult of isolation4 ,for this and other reasons1 more or less in correlation with natural function1 we shall find this class of raw material lowest in value to the paper-maker4 ,it is necessary at this stage to point out that the work of the paper-maker and that of the textile manufacturer are complementary one to the other1 and the supply of fibrous raw material is correspondingly divided3 it may be said1 indeed1 that the paper industry subsists upon the rejecta of the textile manufactures4 ,the working up of discontinuous fibre elements into thread1 which is the purpose of the complicated operations of the spinner1 is conditioned by the length and strength of these ultimate fibres4 ,paper-making1 on the other hand1 requires that the raw material shall be previously reduced to the condition of minute subdivision of the constituent fibres1 and therefore can avail itself of fibrous raw material altogether valueless to the spinner1 and of textile materials which from any cause have become of no value as such4 ,to the raw materials of the paper-maker1 which we have briefly outlined above1 we must therefore add1 as a supplementary class1 textiles of all kinds1 such as rags1 rope1 and thread4 ,having thus acquired a general idea of the sources of our raw materials1 we must study more closely the substances themselves1 and first of all we must investigate them as we should any other chemical substance1 i4e4 we must get to understand the nature and properties of the matter of which the vegetable fibres are composed4 ,while these exhibit certain variations1 which are considerable1 the substances present a sufficient chemical uniformity to warrant their being designated under a class name3 this name is cellulose4 ,the prototype of the celluloses is the cotton fibre4 #d ,,chapter ,i4 ,,cellulose3 ,,the ,,chemical ,,properties ,,of ,,typical ,,members ,,of ,,the ,,cellulose ,,group1 ,,with ,,reference ,,to ,,their ,,natural ,,history4 ,plants are so far built up of cellulose that it may be called the material basis of the vegetable world4 ,plant tissues1 however1 seldom1 if ever1 consist of pure cellulose1 but contain besides1 other products of growth either chemically combined with the cellulose or mechanically bound up with the tissue1 which are1 according to the nature of their union1 removable either by means of fundamental chemical resolution or by the application of simple solvents4 ,a general method for the isolation of cellulose consists in exposing the moist tissue to the action of chlorine gas or of bromine water in the cold1 and subsequently boiling in dilute ammonia2 repeating this treatment until the alkaline solution no longer dissolves anything from the tissue or fibre4 ,the cellulose is then washed with water1 alcohol1 and ether1 and dried4 ,obtained in this way1 or in the form of bleached cotton1 or of ,swedish filter paper1 it is a white substance1 more or less opaque1 retaining the microscopic features of the tissue or fibre from which it has been isolated4 ,its sp4 gr4 is #abe-ade4 ,its elementary composition is expressed by the percentage numbers 7,schulze7 ,c #ddj #ddb ,h #fc #fd ,o #dig #did or by the corresponding empirical formula1 viz4 ,c#f;,h#aj,o#e4 ,these numbers represent the composition of the ash-free cellulose4 ,nearly all celluloses contain a certain proportion1 #e however small1 of mineral constituents1 and the union of these with the organic portion of the fibre or tissue is of such a nature that the ash left on ignition preserves the form of the original4 ,it is only in the growing point of certain young shoots that the cellulose tissue is free from mineral constituents4 7,hofmeister47 ,as already indicated1 cellulose is insoluble in all simple solvents2 it is1 however1 dissolved by certain reagents1 but only by virtue of a preceding chemical modification4 ,an exception to this is to be found1 perhaps1 in the ammoniacal solution of cupric oxide 7,schweitzer's reagent71 in which it dissolves without essential modification1 being recovered by precipitation1 in a form which is chemically identical with the original1 though differing1 of course1 in being structureless1 or amorphous4 ,this reagent may be employed in a variety of forms1 but the following method of using it is to be recommended as the most certain in its results4 ,the substance to be operated upon is intimately mixed with copper turnings in a tube which is narrowed below and provided with a stopcock4 ,strong ammonia is poured upon the contents of the tube and1 after being allowed to stand for some minutes1 is drawn off and returned to the tube2 the operation is several times repeated until the solution of the substance is effected4 ,in order to facilitate the oxidation of the copper by the atmospheric oxygen1 a current of air may be aspirated through the apparatus4 ,the solution of the oxide prepared in this way is more effective in its action on cellulose than that obtained by dissolving the precipitated hydrate in ammonia4 ,cellulosic tissues in contact with this reagent are seen to undergo a disaggregation of their fibres1 which swell up1 become gelatinous1 and disappear in solution4 ,on adding an acid to the viscous solution1 a precipitate of the amorphous cellulose is obtained in the form of a jelly resembling hydrated alumina2 after washing and drying1 it forms a brownish1 brittle1 horny mass4 ,the cellulose is also precipitated upon simply diluting the viscous solution with water and allowing it to stand #f #h-aj days in a closed vessel4 ,from this observation it was inferred by ,erdmann that the cellulose could not be considered as dissolved in the strict sense of the word1 but the experiments of ,cramer upon the osmotic properties of the solution proved this inference to be unfounded1 and that cellulose is actually dissolved by the ammoniacal solution of copper oxide4 ,on treating the ammonio-cupric solution of cellulose with metallic zinc1 this metal precipitates the copper1 replacing it in the solution1 and producing the corresponding ammonio-zincic solution of cellulose1 which is colourless4 ,some of these solutions are lvo-gyrate4 ,cellulose1 in those forms to which the application of the term has been hitherto restricted1 is a comparatively inert substance1 and its reactions are consequently few4 ,one of these is available for the identification of cellulose1 and is chiefly used in the microscopical examinations of tissues3 this is its reaction with iodine4 ,cellulose is not coloured blue by a solution of iodine excepting under the simultaneous influence of hydriodic acid1 potassium iodide1 sulphuric acid1 phosphoric acid1 or zinc iodide or chloride4 ,the solution is prepared in the following way3 zinc is dissolved to saturation in hydrochloric acid1 and the solution is evaporated to sp4 gr4 #bj2 to #ij parts of this solution are added #f parts potassium iodide dissolved in #aj parts of water2 and in this solution iodine is dissolved to saturation4 ,by this solution cellulose is coloured instantly a deep-blue or violet4 ,for the identification of cellulose in the gross1 mere inspection is usually sufficient2 confirmatory evidence is afforded by an observation of the action of the ammonio-copper reagent1 and of the absence of reaction with chlorine water4 7,see p4 #ah47 ,cellulose in its earlier stages of elaboration has no action upon light2 but with age it acquires the property of double refraction1 not1 as has been shown by experiment1 by virtue of its state of aggregation1 but of its molecular constitution 7,sachs74 #g ,animal ,cellulose4--,the mantles of many of the mollusca1 e4g4 the ,pyrosomid1 ,salpid1 and ,phallusia mammillaris1 contain a resistant substance which1 after isolation by chemical treatment1 has been found to be identical both in composition and properties with vegetable cellulose4 ,cellulose has also been stated to occur in degenerated human spleen and in certain parts of the brain4 ,compounds of ,cellulose4--,the chemical inertness of cellulose is a matter of everyday experience in the laboratory1 where it fulfils the important function of a filtering medium in the greater number of separations of solids from liquids4 ,its combinations with acids and with basic oxides are1 as might be expected1 few and of little stability4 ,it has been shown by ,mills that cellulose 7cotton7 in common with certain other organic fibrous substances1 when immersed in dilute solutions of the acids or basic oxides1 condenses these bodies within itself at the expense of the surrounding solution1 which is proportionately weakened4 ,this effect of concentration is sufficiently uniform and constant to lead us to assign it to a chemical cause1 and the view is strengthened by a consideration of the relative effects upon the various acids and bases which have been investigated1 and brought to the following numerical expression3--,weight of cotton #c grm4 7with #fi per cent4 ,h#b,o and #jje per cent4 ash7--i4e4 #bhic anhydrous fibre4 ,strength of solution about #je grm4 of the reagent in #bej cc4 ,temp4 ,time4 ,weight absorbed4 ,h#b,,so#d #d ,c4 7#ci ,f47 #c min #jjjdie ,h,cl #jjjgcc ,na,o,h #jjbjbj ,the molecular ratio of the absorption1 in the two latter1 is #c ,h,cl 3 #aj ,na,o,h1 and it is noteworthy that the same ratio was observed for silk4 ,cellulose removes barium hydrate from its solution in wafer to form with it an insoluble compound4 ,on adding lead acetate to the solution of cellulose in the ammonio-copper reagent1 so prepared as to contain no carbonate1 a #h precipitate is obtained consisting of a compound of cellulose with lead oxide1 but in variable proportions4 ,the compound ,c#f;,h#aj,o#e,pb,o is formed by the action of finely-divided lead oxide upon the above solution4 ,quite recently it has been shown 7,o',shea1 ,chem4 ,news1 ,may #bhth1 #ahhf7 that when dilute solutions of lead are passed through ordinary filter paper1 a certain amount is retained which cannot be removed by washing4 ,cellulose does not combine with metallic salts1 a fact which has been established incidentally to researches upon the mode of action of mordants4 ,the combinations of cellulose with acid radicles 7ethereal salts7 are both definite and stable4 ,triacetyl ,cellulose ,c#f;,h#g 7,c#b;,h#c,o7#c ,o#e is formed by treating cellulose with six times its weight of acetic anhydride at #ahj ,c4 7#cef ,f474 ,the product of the reaction is a syrupy solution from which the compound in question separates on dilution with water as a white flocculent precipitate4 ,triacetyl cellulose is insoluble in alcohol and in ether1 but soluble in glacial acetic acid4 ,it is easily saponified by boiling with a solution of potassium hydrate1 the cellulose being regenerated4 ,no derivative containing more than three acetyl groups has been obtained2 but a mixture of the mono-and di-acetyl cellulose is formed in treating cellulose with only twice its weight of acetic anhydride1 the formation of these bodies being unattended by their solution4 ,whenever cellulose1 in any form1 is brought into contact with strong nitric acid at a low temperature1 a nitro product1 or a nitrate1 is formed4 ,the extent of the nitration depends upon the concentration of the acid1 on the time of contact of the cellulose with it1 and on the state of the physical division of the cellulose itself4 ,knop1 and also ,kamarsch1 and ,heeren1 found that a mixture of sulphuric acid and nitric acid also formed nitrates of cellulose2 and still later 7#ahdg71 ,millon and ,gaudin employed a mixture of sulphuric acid and nitrates of soda or potash1 which they found to have the same effect4 #i ,several well characterised nitrates have been formed1 but it is a very difficult matter to prepare any one in a state of purity1 and without admixture of a higher or lower nitrated body4 ,the following are known3-- ,hexa-nitrate1 ,c#ab;,h#ad,o#d7,,no#c7f1a gun cotton4 ,in the formation of this body1 nitric acid of sp4 gr4 #ae1 and sulphuric acid of sp4 gr4 #ahd are mixed1 in varying proportions1 about #c of nitric to #a of sulphuric 7sometimes this proportion is reversed71 and cotton is immersed in this at a temperature not exceeding #aj ,c4 7#ej ,f47 for #bd hours3 #ajj parts of cellulose yield about #age of cellulose nitrate4 ,the hexa-nitrate so prepared is insoluble in alcohol1 ether1 or mixtures of both1 in glacial acetic acid or in methyl alcohol4 ,acetone dissolves it very slowly4 ,this is the most explosive gun-cotton4 ,it ignites at #afj-agj ,c4 7#cbj-cch ,f474 ,according to ,eder the mixtures of nitre and sulphuric acid do not give this nitrate4 ,ordinary gun cotton may contain as much as #ab per cent4 of nitrates soluble in ether-alcohol4 ,the hexa-nitrate seems to be the only one quite insoluble in ether-alcohol4 ,footnote #a3 ,to represent the series of cellulose nitrates so as to avoid fractional proportions1 the ordinary empirical formula is doubled and the nomenclature has reference to this double molecule4 ,penta-nitrate1 ,c#ab;,h#ae,o#e7,,no#c7e4 ,this composition has been very commonly ascribed to gun-cotton4 ,it is difficult1 if not impossible1 to prepare it in a state of purity by the direct action of the acid on cellulose4 ,the best method is the one devised by ,eder1 making use of the property discovered by de ,vrij1 that gun-cotton 7hexa-nitrate7 dissolves in nitric acid at about #hj-ij ,c4 7#agf-aid ,f47 and is precipitated1 as the pentanitrate1 by concentrated sulphuric acid after cooling to #j ,c4 7#cb ,f472 after mixing with a larger volume of water1 and washing the precipitate with water and then with alcohol1 it is dissolved in ether-alcohol1 and again precipitated with water1 when it is obtained pure4 ,this nitrate is insoluble in alcohol1 but dissolves readily #aj in ether-alcohol1 and slightly in acetic acid4 ,strong potash solution converts this nitrate into the di-nitrate1 ,c#ab;,h#ah,o#h 7,,no#c7b4 ,the tetra- and tri-nitrates 7collodion pyroxyline7 are generally formed together when cellulose is treated with a more dilute nitric acid1 and at a higher temperature1 and for a much shorter time 7#ac to #bj minutes71 than in the formation of the hexa-nitrate4 ,it is not possible to separate them1 as they are soluble to the same extent in ether-alcohol1 acetic ether1 acetic acid or wood spirit4 ,on treatment with concentrated nitric and sulphuric acids1 both the tri-and tetra-nitrates are converted into penta-nitrate and hexa-nitrate4 ,potash and ammonia convert them into di-nitrate4 ,cellulose di-nitrate1 ,c#ah;,h#ac,o#h 7,,no#c7b always results as the final product of the action of alkalis on the other nitrates1 and also from the action of hot1 somewhat dilute1 nitric acid on cellulose4 ,the di-nitrate is very soluble in ether-alcohol1 acetic ether1 and in absolute alcohol4 ,further action of alkalis on the di-nitrate results in a complete decomposition of the molecule1 some organic acids and tarry matters being formed4 ,the reactions and resolution products of this body have1 however1 been but slightly studied1 and apparently not at all with the view to elucidate anything respecting the constitution of cellulose itself4 ,cellulose and ,chlorine4--,dry chlorine gas has no action upon cellulose1 but the presence of water determines an indirect oxidising action4 ,this oxidising action results from the decomposition of water by chlorine with formation of hydrochloric acid and liberation of oxygen4 ,the reaction1 however1 can only take place in the presence of light4 ,cellulose and ,oxygen4--,when cotton is exposed for some time to the action of a solution of bleaching powder1 in the cold1 and with access of air1 e4g4 when a piece of white calico is moistened with the solution1 squeezed out and exposed to the air1 it is found to undergo gradual disintegration accompanied by a change in composition1 and an elementary #aa analysis of the product shows it to contain less carbon and more oxygen than the original cellulose4 ,the following percentage numbers indicate the composition of these oxidised derivatives of cellulose1 and the progress of the oxidation3-- #ab hours' exposure4 #bd hours' exposure4 ,c #dcgh #dcdg #dcjj #dbij ,h #ehe #fac #fbh #fah ,o #ejcg #ejdj #ejgb #ejib ,other oxidising agents produce similar results2 even by exposure to air and light1 cellulose is slowly converted into these oxidised derivatives4#b ,from their mode of formation1 they have been termed oxycelluloses1 and to distinguish them from a series of more highly oxidised derivatives1 produced by the action of nitric acid upon cellulose1 which they nevertheless resemble in many of their characteristics1 the prefix is employed4 ,the following are the distinguishing features of the oxycelluloses as represented by the more extreme of the above mentioned products4 ,it reduces ,fehling's solution at the boiling temperature1 and the cuprous oxide is deposited upon the fibre in a state of intimate union1 producing the effect of an orange dye4 ,it attracts the basic colouring matters from their solutions and is dyed to a full shade1 the depth of colour being proportionate to the amount of oxidation to which the cellulose has been subjected4 ,see also p4 #dc4 ,treated with a warm solution of phenylhydrazine salts in water1 it is coloured a bright lemon-yellow4 ,its most remarkable property is its attraction for the vanadium compounds1 which is so powerful that combination may be proved to take place when this element in the form of chloride is presented to the oxycellulose in an aqueous solution containing not more than #a in #a1jjj1jjj1jjj1jjj parts4 ,footnote #b3 ,witz4 ,bull4 ,soc4 ,ind4 ,rouen1 ,x4 #daf1 and ,,xi4 #ahi4 ,the oxycellulose resulting1 as already indicated1 from the action of dilute nitric acid upon cellulose1 will be subsequently considered1 under the head of the decompositions of cellulose1 to which the reaction which we have been considering may be regarded as transitional4 #ab ,decomposition of ,cellulose4--,acids4--,of the decomposition of cellulose by artificial means1 i4e4 by the action of reagents1 the most important are those which disclose the relationship which it bears to the group of so-called carbo-hydrates4 ,cellulose is1 indeed1 a highly elaborated carbo-hydrate1 differing from dextrin and starch1 not so much in its essential constitution as in the molecular arrangement which has been impressed upon it in and through the life of the plant4 ,there are numerous observations in biological science which demonstrate the close connection1 and in many cases the physiological equivalence of the members of this natural group1 which includes the sugars1 dextrin1 starches1 and cellulose4 ,the following facts show the constitutional or chemical ties which underlie their interdependence4 ,amyloid4--,when cotton is treated with #cj times its weight of sulphuric acid somewhat diluted 7#a part ,h#b,o1 #d parts ,h#b,,so#d7 it quickly dissolves1 the solution being at first gelatinous1 becoming afterwards syrupy4 ,on pouring this solution into water1 a white flocculent precipitate is formed1 consisting of a substance closely resembling the cellulose from which it is derived1 differing1 indeed1 only in being amorphous1 and in being coloured blue by iodine4 ,this substance1 from its resemblance to starch1 has been called amyloid4 ,when sufficiently dehydrated it constitutes a swollen starchy mass1 which dries to a brittle transparent solid4 ,this transformation appears to consist in a simple hydration of the cellulose molecule1 thus3-- ,cellulose4 ,amyloid4 #b 7,c#f;,h#aj,o#e7 ,h#b,o ,c#ab;,h#bb,o#aa4 ,the modification of cellulose1 which occurs on the conversion of unsized paper into the so-called parchment paper1 by exposure for a short time to the action of strong sulphuric acid1 and subsequent washing and drying1 consists doubtless in a superficial conversion of the cellulose into amyloid1 or a body closely resembling it4 ,hydracellulose4--,closely related in composition to the above #ac described amyloid1 is the substance called hydracellulose1 into which cellulose is converted by exposure for some time to the action of moderately strong sulphuric1 or hydrochloric acids 7sp4 gr4 #ace74 ,this substance is also formed by the action of very weak acids1 if the exposure of the cellulose be sufficiently prolonged4 ,its formation is accompanied by the complete disintegration of the cellulose4 ,if the action of strong sulphuric acid be prolonged1 a further modification ensues1 dextrin or sugar being formed4 ,these products have not been sufficiently studied to have established their exact identity with any of the substances known under these group-names4 ,the dextrin has a close resemblance to the dextrin obtained from starch2 the sugar is susceptible of fermentation2 but beyond this nothing specific is known of these bodies4 ,their general properties1 however1 and mode of formation1 sufficiently establish the fact that cellulose itself is constituted of similar molecules4 ,the action of zinc chloride solution upon cellulose is similar to that of sulphuric acid4 ,cellulose in contact with iron1 and in presence of air and moisture1 is converted into a sugar and a gummy substance1 which latter is converted into a sugar on boiling with dilute acids4 ,oxidised by potassium permanganate or bichromate in presence of acetic acid1 it is converted into glucose1 dextrin1 and formic acid4 ,cellulose and nitric acid3 ,oxycellulose4#c--,on digesting cellulose with nitric acid 7sp4 gr4 #ac7 at #ajj ,c4 7#bab ,f471 a considerable quantity of oxalic acid is formed2 but after prolonged digestion1 a residue remains1 which yields but very slowly to the action of the acid4 ,this substance1 which is white and flocculent1 when thrown upon a filter and washed with water1 combines with the latter to form a gelatinous hydrate4 ,it dissolves in dilute alkalis1 but without forming a stable compound with the base4 ,it usually amounts to about #cj per cent4 of the cellulose acted upon4 ,its elementary composition is expressed by the formula #ad ,c#ah;,h#bf,o#af 7,c #dcd1 ,h #ec per cent474 ,treated with a mixture of concentrated sulphuric and nitric acids1 it dissolves1 and1 on pouring the solution into water1 the compound ,c#ah;,h#bc,o#ac7,,no#c7c separates as a white flocculent precipitate4 ,in its essential properties therefore oxycellulose exhibits a close resemblance to cellulose itself4 ,this oxycellulose is distinguished from the members of the cellulose group by dissolving in concentrated sulphuric acid with development of a pink colour4 ,it appears to stand in very close relationship to the group of pectic substances1 which are oxidised derivatives of cellulose4 ,footnote #c3 ,cross and ,bevan1 ,chem4 ,soc4 ,journ41 xliii4 p4 #bc4 ,alkalis4--,concentrated solutions of the caustic alkalis in the cold attack and disintegrate cellulose but slowly4 ,the action is in many cases merely superficial4 ,dilute solutions of the alkalis are without action upon cellulose even at the boiling temperature1 unless the condition of oxidation is super-added2 in this case1 acid bodies are found4 ,the extreme product of the oxidation of cellulose in presence of the caustic alkalis is oxalic acid2 this acid has indeed been prepared on the commercial scale by the 8fusion0 of cellulosic substances1 with mixture of sodium and potassium hydrates4 ,malic acid has been obtained as an intermediate product of this decomposition4 ,by potassium permanganate in presence of potassium hydrate1 both in solution1 finely divided cellulose is oxidised to a syrupy mixture of acids resembling in composition and properties ,frmy's meta-pectic acid4 ,a similar decomposition is effected by concentrated solutions of the hypochlorites1 employed cold4 ,water at ,high ,temperature4--,cellulose itself is only slightly affected by exposure to a temperature of #bjj ,c4 7#cib ,f47 but in contact with water at this temperature1 in sealed glass#d most part into dark brown insoluble products1 a portion1 however1 passing into solution in the water1 imparting to it a deep yellow colour4 ,a large quantity of carbonic acid is #ae formed1 and the solution contains in addition to formic acid an appreciable quantity of pyrocatechol4 ,the formation of this aromatic substance from cellulose is1 perhaps1 the most noticeable feature of the decomposition4 ,footnote #d3 ,the action of alkaline substances dissolved from the glass must be taken into account in this decomposition4 ,decomposition by means of ferments1 c4--,the soluble ferment of the foxglove has been found to convert cellulose into glucose and dextrin4 ,the fluid from the vermiform appendix of the rabbit has also been found to digest cellulose with liberation of marsh gas and formation of a soluble compound which reduces cupric oxide in alkaline solution4 ,humus4--,in the natural decay of cellulosic structures a large quantity of marsh gas is formed1 and solid products are formed1 which are usually known as humic or ulmic substances4 ,these bodies are amorphous1 are largely dissolved by alkaline solutions1 and are attacked by chlorine gas in presence of moisture1 yielding yellow coloured chlorinated derivatives whose composition has a general resemblance to the chlorinated compounds obtained from the compound celluloses1 to be hereafter described4 ,the most important part which ulmic substances play in the economy of nature1 is in the composition of soils4 ,it is doubtful whether they act directly as fertilisers1 but by their action upon the mineral constituents of soils they contribute to the supply of these necessary elements of growth to the plant4 ,synthesis of ,cellulose4--,a transformation of certain soluble carbo-hydrates into cellulose1 which may be regarded as a proximate synthesis of cellulose1 has recently been brought to light4 ,this is set up spontaneously in beet-juice1 and results in the formation of a hard white substance1 insoluble in boiling dilute potash1 soluble in the ammonio-copper reagent1 converted by sulphuric acid into dextrin and sugar1 and by nitric acid into oxalic acid4 ,on adding some of these cellulose lumps to a solution of pure cane-sugar1 a further transformation of the saccharose into the same substance is brought about4 ,at the same time there is simultaneously produced a gummy substance1 which is precipitated by #af alcohol as a white amorphous caoutchouc-like mass1 of the same composition as cellulose1 but swelling up with water1 and otherwise differing in its physical properties from cellulose4 ,this latter substance is also formed by the action of diastaste upon a solution of saccharose4 ,the process of cellulosic fermentation may be represented by the equation3 n4 7,c#ab;,h#bb,o#aa7 n4 7,c#f;,h#aj,o#e7 n4 7,c#f;,h#ab,o#f7 ,saccharose4 ,cellulose4 ,glucose4 ,a similar transformation takes place under the influence of certain fatty seeds1 e4 g4 those of rape and colza2 and it is probable that the formation of cellulose in living plants may take place at the expense of saccharose and under the influence of ferments4 ,in support of this it has been established that in the sugar-cane1 the formation of wood--i4e4 cellulose--is accompanied pari passu by a decrease in saccharose4 ,more recently1 ,a4 ,brown 7,chem4 ,soc4 ,journ41 #dcb1 #ahhf7 has investigated the formation of cellulose by the 8vinegar plant0 growing in solutions of the carbo-hydrates1 e4 g4 dextrose in yeast-water4 ,the cells elaborate an extra-cellular fibrin1 which acts as a 8cell-collecting medium10 and they possess therefore a two-sided activity1 i4e4 the property above mentioned1 in addition to their strictly fermentative activity4 ,the cellulose film in question was found to contain #ej to #fj per cent4 of pure cellulose4 ,it is noteworthy that in a solution of levulose the growth of the 8plant0 is unattended by fermentative action1 #cc per cent4 of the substance being1 on the other hand1 transformed into cellulose4 ,modifications of ,cellulose in the ,plant4 ,compound ,celluloses4--,it has been already stated that cellulose occurs in nature for the most part in a form different from that in which we have hitherto considered it1 viz4 either combined or mixed with other substances which are of such a nature that they may be removed by a chemical process1 more or less simple4 ,one of the most characteristic of these modified celluloses constitutes the jute fibre1 the isolated bast of an ,indian plant1 #ag which has an enormous industrial application for the coarser textile purposes4 ,the chemistry of jute throws light on the course of lignification1 the process by which cellulose is modified into wood1 and in studying it in preference to wood we have the advantage of studying a simple tissue4 ,like cellulose1 jute dissolves in cuprammonia1 and is similarly acted upon by the concentrated acids4 ,by nitric acids it is converted into nitric ethers1 which are yellow coloured1 but in other respects closely resemble the pyroxylins4 ,they are entirely soluble in acetone4 ,jute differs from cellulose in the following respects3 its percentage composition 7excluding ash7 is ,c #dgj #dhj per cent4 ,h #ei #eg ,o #dga #dfc ,it is harsher to the touch1 and its colour varies from grey to brown2 it combines directly with the greater number of the organic colouring matters1 removing them from solution1 i4e41 becoming dyed with them2 it is coloured deep yellow by immersion in a solution of aniline sulphate2 moistened with a solution of phloroglucol and afterwards with hydrochloric acid1 it gives a deep red coloration2 with pyrrol also in presence of hydrochloric acid it gives a deep carmine colour2 it is attacked and partially converted into soluble products by a number of reagents which have no action1 under similar conditions1 upon cellulose4 ,certain of these we must consider more in detail4 ,iodine4--,jute absorbs iodine from its solution in potassium iodide4 ,this action is characteristic of all lignified tissues1 the quantity of iodine taken up being proportional to the amount of lignification4 ,if the physical conditions remain the same1 the amounts of iodine absorbed will be found to be constant for each particular fibre4 ,this constancy points to the formation of a definite chemical compound1 probably resembling the blue compound of starch and iodine4 ,this property may be made available for the estimation of the #ah amount of mechanical wood-pulp in papers2 it will be more fully considered elsewhere4 ,bromine4--,jute1 exposed to the action of bromine water in the cold1 combines with the halogen1 being oxidised at the same time1 and the products may be dissolved by boiling the modified fibre in weak alkaline solutions4 ,on repeating this treatment four or five times1 a residue of cellulose is ultimately obtained1 amounting to #gb or #gc per cent4 of the original fibre3 the cellulose is obtained in the form of the disintegrated fibre elements4 ,on allowing the halogen to act in presence of an alkali1 i4e41 as hypobromite1 not only is its action intensified and accelerated1 but its modus operandi more clearly revealed4 ,the chief products are in this case1 carbonic acid1 bromoform ,c,h,br#c 7which may be isolated by distillation71 and cellulose4 ,at the same time the yield of cellulose is considerably less than by the former method1 the cellulose itself being attacked by the hypobromite4 ,chlorine4--,dry chlorine gas has no action upon jute even when the temperature is raised to #adj ,c4 7#bhd ,f471 but the presence of moisture determines rapid combination1 at ordinary temperature1 accompanied by evolution of heat4 ,the colour of the jute changes to a bright yellow1 which1 on treatment of the fibre with a solution of sodium sulphite1 gives place to a pure magenta4 ,this reaction is characteristic of all lignified tissues1 and is a valuable aid in the micro-chemical examination of plant structures4 ,for this purpose1 the reagent may be employed in the form of chlorine water2 the sections or small fragments to be examined are allowed to remain in this solution a short time1 and then mounted for observation in a dilute solution of sodium sulphite4 ,by combination with chlorine the fibre substance or ligno-cellulose is partially resolved4 ,alcohol dissolves away from the chlorinated fibre1 a bright yellow substance1 which is precipitated in yellow flocks on pouring the solution into water4 ,this chlorinated derivative has the composition ,c#ai;,h#ah;,cl#d,o#i4 ,by this formula1 as well as by its colour reactions1 and by its yielding protocatechuic acid on fusion with potash1 it is #ai shown to be related to the trihydric phenols1 and to the tannins which are derivatives of these4 ,after dissolving away this compound by exhaustive treatment with alcohol1 the fibre still gives a brilliant reaction with sodium sulphite1 showing that a portion is still held back in combination with the cellulose1 or cellulose residue4 ,on treating the residual fibre with boiling nitric acid1 a considerable quantity of chloropicrin ,c,cl#c,,no#b is formed1 and it is probable that the union of the molecule ,c#ai;,h#ah;,cl#d,o#i with the cellulose may be effected by the aldehyde#e molecule ,c,cl#c;,,coh2 each group being contained in the original lignocellulose1 the action of the chlorine tending to disturb the atomic equilibrium and to rearrange the atoms into groups1 which in their modified form have less mutual coherence4 ,if the chlorinated fibre be directly boiled with the sodium sulphite solution1 its resolution into cellulose and soluble non-cellulose derivatives is complete3 and this treatment constitutes the most simple and rapid method of estimating the cellulose in lignified tissues4 ,it is only necessary finally to wash the cellulose with hot water containing a little acetic acid 7when placed in a funnel it acts as its own filter71 and then with1 alcohol1 when it may be dried and weighed4 ,in order to ensure the resolution of the fibre by a single chlorination 7in the case of jute1 and the like71 it must1 previously to exposure to the gas1 be boiled in a dilute 7#a per cent47 solution of potassic hydrate4 ,in the case of wood and other more resistant structures1 it will be necessary to repeat the chlorination4 ,footnote #e3 ,furfural may also be isolated from the chlorinated jute2 the survival of this aldehyde is noteworthy4 ,the percentage of cellulose yielded by this method is1 in the case of jute1 usually #b-c per cent4 higher than by the bromine method4 ,moreover1 if the temperature be maintained at #j ,c4 7#cb ,f471 by placing the fibre1 which is to be exposed to the action of the gas1 in contact with pounded ice1 the percentage may be still further increased1 amounting #bj in some cases to #hj-hb4 ,corresponding to this increased yield1 the cellulose is obtained in long filaments4 ,it will be seen1 therefore1 that the cellulose isolated by chemical treatment from a compound cellulose is affected both in character and quantity by the process employed1 and it is affected in a much greater degree than the cellulose itself exposed to the same treatment1 after isolation4 ,the composition of the cellulose obtained in this way differs from that of celluloses1 such as cotton1 which exist in the plant in an isolated and more fully formed condition2 it contains #dc per cent4 ,c and #f per cent4 ,h1 corresponding to the formula n #c ,c#f;,h#aj,o#e;,h#b,o4 ,the composition of this cellulose will be seen to be identical with that of certain of the oxycelluloses previously described2 and its properties are1 moreover1 those of an oxycellulose4 ,these facts go to show that the jute fibre substance1 and the substances allied to it1 are compounds of cellulose with other molecules1 i4e4 they are compound celluloses4 ,they may be conveniently grouped under the term ligno-cellulose4 ,dilute ,mineral ,acids4--,under the action of dilute sulphuric or hydrochloric acid 7#e-aj per cent47 at #fj-hj ,c4 7#adj-agf ,f471 a considerable portion of the fibre substance is dissolved4 ,the action of either reagent is of course purely hydrolytic2 and the hydrolysis is of the simplest character1 since the substance dissolved as well as the residual fibre are found to have the same percentage composition4 ,moreover1 the residual fibre1 though having undergone a profound structural modification1 and having been converted into a disintegrated mass of brittle fragments1 still preserves the chemical characteristics of the original1 unaltered4 ,thus it is converted by the action of chlorine into a similar complex of derivatives1 yielding on resolution by sodium sulphite solution #ge per cent4 of cellulose2 also when acted upon by alkaline hypobromite it yields bromoform4 ,under the action of these hydrolytic reagents1 therefore1 the fibre shows itself to be essentially a chemical whole4 ,at the boiling temperature1 these acids resolve as well as dissolve the fibre substance1 and the volatile products are acetic acid and the peculiar aldehyde #ba furfural ,c#d;,h#c,o4,,coh4 ,the yield of this aldehyde may be raised with suitable precautions to #ae-bj per cent4 of the raw fibre4 ,the action of dilute nitric acid upon the fibre differs from that of the above-mentioned acids1 in effecting its resolution into soluble derivatives and insoluble cellulose2 the yield of the latter when the reaction is conducted at #fj ,c4 7#adj ,f471 with #e parts ,,hno#c is #fj per cent4 only1 showing that in the process of isolation some of the cellulose itself is attacked and converted into soluble products4 ,schulze's method of isolating cellulose from wood1 and from the ligno-celluloses generally1 consisted in macerating them for #ab to #ad days with #h_/aj their weight of potassium chlorate dissolved in #ab parts by weight of nitric acid 7sp4 gr4 #aaj71 and completing the resolution by afterwards boiling with dilute ammonia4 ,by the action of a more concentrated acid1 #ej per cent4 ,,hno#c1 at #hj ,c4 7#agf ,f471 a soluble derivative is obtained which has the composition 7,c#be;,h#dj,,no#be74 ,it is a syrupy1 highly acid body1 dyeing animal fibres a deep yellow shade1 and giving with the earthy bases salts of the formula 7,c#be;,h#cb,,no#be,m#d71 which are precipitated by alcohol from their aqueous solution in the form of bright yellow flocks that dry to a yellow powder4 ,dilute ,alkalis4--,the action of boiling dilute solutions of the caustic alkalis upon the ligno-celluloses is similar to that of the dilute acids1 viz41 purely hydrolytic1 causing no essential change in the composition of the fibre substance4 ,water at ,high ,temperatures4--,the ligno-celluloses undergo a profound modification when heated with water at elevated temperatures4 ,they are to a great extent converted into soluble products1 of which a large proportion are the volatile bodies1 acetic and formic acids and furfural4 ,the residual fibre is found to be more or less disintegrated1 and of a dark-brown colour1 but preserving many of the chemical features of the original4 ,a similar disintegration is caused by exposing the ligno-celluloses in a dry state to an atmosphere of superheated steam1 the effect being much increased if the ligno-cellulose be previously bleached by any of the ordinary #bb processes1 i4e41 under oxidising conditions4 ,in these decompositions oxidation1 as well as hydration1 plays an important part4 ,it is found that the presence of small quantities of reducing agents1 e4g41 sulphites1 exerts a remarkable effect in retarding and often entirely preventing these changes4 ,it is probable that they act in obviating an initial change1 which1 with a cumulative reaction on the fibre1 effects the profound resolutions above described4 7,see p4 #ga47 ,concentrated ,hydrochloric ,acid4--,when exposed to the concentrated aqueous acid at ordinary temperatures1 ligno-cellulose undergoes a profound structural modification1 and is largely converted into soluble bodies4 ,the disintegrated residue reacts with chlorine similarly to the original jute1 but the quantity of cellulose isolated by subsequent treatment with alkaline solutions is only #ej per cent4 of the original4 ,since jute cellulose1 after isolation1 exhibits under similar treatment a much smaller conversion into soluble products1 #aj per cent4 as compared with #cc1 we have here further evidence that the cellulose is present in the fibre in a condition chemically different from that of the isolated cellulose4 ,sulphuric ,acid4--,on triturating the fibre with the concentrated acid1 it dissolves to a brownish-purple solution2 on pouring this solution into water1 a substance is precipitated in dark-brown flocks2 when dried it has the following composition3 ,c #fdd ,h #dd ,o #cab ,the solution yields on distillation furfural and acetic acid4 ,nitric and ,sulphuric ,acids4--7#a 3 #b by vol47--,by the action of these acids ligno-cellulose is converted into yellow-coloured explosive compounds1 preserving all the external features of the original fibre1 and showing a close resemblance to the pyroxylins4 ,the increase in weight resulting from the fixation of the #bc nitric acid residue is approximately equal to that of cotton 8nitrated0 under the same conditions4 ,they are freely soluble in acetone4 ,on examination they prove to be homogeneous4 ,if the fibre be warmed with the mixture after the first reaction is completed1 it dissolves4 ,the solution is found to contain oxalic1 succinic1 and suberic acids1 but no aromatic nitro-derivatives1 whereas if ligno-cellulose contain a benzene nucleus1 as has been supposed1 such derivatives could not fail to be formed under these conditions4 ,animal ,digestion of ,ligno-cellulose4--,it has long been known that the urine of herbivorous animals contains hippuric acid1 or benzoyl glycocine1 as a normal constituent1 and it has been shown that the benzoyl radicle necessary to form this body by reacting with the glycocine of the liver1 is a product of the digestion of ligno-cellulose4 ,on the other hand1 it has been shown that ligno-cellulose contains no benzene compounds as such4 ,we have therefore1 in this fact additional evidence that a portion of the complex ligno-cellulose molecule is in what we may term a potentially aromatic condition4 ,distribution of ,ligno-celluloses4--,as already indicated1 the distribution of the ligno-celluloses is extremely wide2 they are met with in every variety of vegetable tissue1 and their presence is readily ascertained by the reaction of chlorination already described4 ,of these ligno-celluloses most closely allied to jute1 we may mention the stony concretions of pears 7glycodrupose7 and the main tissue of fir wood 7glycolignose74 ,decay of ,ligno-cellulose4--,when a mass of ligno-cellulose 7jute7 is allowed to lie for a long period in a damp state1 it undergoes resolution accompanied by structural disintegration4 ,the soluble products of this change are acid bodies of the pectic class1 and astringent substances closely resembling the tannins4 ,in this decomposition also we have evidence of the plastic condition of the ligno-cellulose molecule1 of the variety of its modes of resolution1 according to the various directions in which it is attacked4 ,decomposition by ,heat4--,the celluloses burn in the air with #bd a quiet luminous flame4 ,when heated out of contact with the air1 they are completely resolved into gaseous and volatile products on the one hand1 and a residual black mass1 which1 although containing a high percentage of carbon1 and approximating in its properties to the element itself1 nevertheless contains hydrogen and oxygen in essential chemical union with the carbon1 in consequence of which it is expedient to apply the term pseudo-carbon to this as to all similar substances4 ,the volatile products of the destructive distillation of pure cellulose have not been studied1 but those of certain of the ligno-celluloses 7woods7 have been exhaustively investigated1 and have moreover1 a very considerable commercial importance4 ,they divide themselves into two groups 7a7 soluble in water1 and containing1 besides water1 acetic acid1 methyl alcohol1 methylic acetate and acetone2 7b7 insoluble in water1 or wood tar1 containing tolyene1 xylene1 cymene1 naphthalene1 chrysene1 anthracene1 retene1 pittacal1 cedriret solid paraffins1 c4 ,the quantity of the pseudo-carbon 7charcoal7 obtained is1 in the case of the hard woods1 about #be per cent4 of their weight4 ,the liquid portion of the products amount to some #ej per cent41 and contains about one-fifth of the carbon of the original wood2 the remainder of the carbon is eliminated in the gaseous form 7,,co1 ,,co#b1 c474 ,the proportion of acetic acid is #c-d per cent41 the tar amounting to #g-h per cent4 ,the coals themselves may be regarded as pseudo-carbon derivatives of celluloses1 formed by a process of molecular condensation1 the true nature of which remains a matter of speculation4 ,in this view1 the whole of our vast series of aromatic or benzene compounds1 derived as they are from the products of the destructive distillation of coals1 may be traced back to a cellulose origin4 ,pseudo-carbons are obtained as products of the action of various reagents upon the celluloses1 and other of the so-called carbo-hydrates4 ,these reagents1 such as sulphuric acid1 act in virtue of their dehydrating power2 and the recognition of this fact1 together with the supposed 8carbonaceous0 #be character of the product1 led to the erroneous conclusion that the carbohydrates are in such decompositions simply resolved into carbon and water2 a conclusion which seems to derive additional warrant from the peculiar numerical relationship which exists between the ,c1 ,h1 ,o atoms of all the members of the group4 ,their relation is expressed in the general formula ,cn ,h#b7nm7 ,o7nm71 and in the somewhat misleading term carbohydrate1 which is applied to the whole group4 ,we now know that the removal of water from these bodies by the action of dehydrating agents--including heat--follows the ascertained laws of chemical dehydration1 involving molecular condensations and rearrangement1 and that the pseudo-carbons are the extreme terms of a series of such condensations or cumulative resolutions4 ,the matter1 however1 is not as yet sufficiently investigated to enable us to state with any preciseness the mechanism of these changes4 ,still this general statement will enable us to avoid many of the erroneous views which have existed on the subject1 and in a measure to anticipate the results of future investigation4#f ,footnote #f3 ,it is worthy of mention that by the action of chlorine in presence of water1 and by the action of concentrated nitric acid upon the cannel coals1 substitution derivatives are formed resembling those obtained by the action of these reagents respectively upon the ligno-celluloses4 ,general conclusions4--,the aldehydic character of the group of ligno-celluloses is typical of the constituents of plant tissues generally1 and is1 there can be no doubt1 extended to the celluloses4 ,indeed the evidence of biological observation goes to show that the ligno-celluloses are formed1 by a process of chemical modification1 from some more purely cellulosic tissue1 which preceded it1 and with this modification there is1 nevertheless1 a retention of the general features of the original cellulose4 ,in the domain of animal chemistry1 recent investigation has also shown that the development of proteid tissues finds its chemical expression in their aldehydic characteristics1 or as it has been put1 the immediate physical cause of life is to be found in the chemical tension of aldehydes4 ,the meaning of this expression will be readily grasped on #bf reference to the properties of the aldehydes as a group2 their power of combining with oxygen2 of uniting by their own molecules1 to polymerise2 of uniting by way of dehydration2 of combining with the aromatic alcohols2 a consensus of properties which shows them to possess an activity surpassing that of any other group of compounds4 ,the evidence of biology1 added to our knowledge of the properties of these substances1 would lead us therefore to define cellulose as a condensed aldehyde allied to the sugars1 and likewise containing alcoholic ,,oh groups2 and ligno-cellulose a compound cellulose1 containing a cellulose nucleus or residue so combined with certain groups which may be included in the term non-cellulose1 that it yields1 under the action of reagents1 products belonging either to the aromatic1 the furfural1 or the fatty group4 ,adipo-cellulose4--,cork or ,cuticular ,tissue4--,from the mode of formation of cork and cuticular tissues1 it has been concluded that they are also modified celluloses4 ,the aggregate ultimate composition of cork is represented by the following percentage numbers3 ,c #feg ,h #hc ,o #bde ,n #ae ,cork1 however1 unlike the jute fibre1 is by no means chemically simple1 but can be resolved by the action of mere solvents into a number of proximate constituents1 such as acids1 a variety of fatty bodies1 nitrogeneous bodies1 c4 ,cuticular tissues1 such as constitute the covering of fruits1 are more simple in composition2 the cuticle of the apple after purification1 has the following percentage composition3 ,c #gcff ,h #aacg ,o #adig ,the cuticular substance of cotton1 straw1 esparto1 c41 are doubtless similar bodies4 ,these numbers point to a #bg remarkable similarity in composition to the fats1 and1 indeed1 from the results of his study of this tissue1 ,frmy concluded that it was a fat in everything but its physical properties1 of which we may mention insolubility in alcohol and in ether1 and infusibility4 ,this tissue1 however1 as also cork1 contains a cellulose residue1 which may be isolated by any of the methods of treatment given for ligno-cellulose4 ,under the action of boiling nitric acid these tissues are resolved into cellulose on the one hand1 and a series of fatty acids or products of their decomposition1 suberic and adipic acids1 c41 on the other2 the latter amounting in the case of cork to #dj per cent4 of the weight of the substance treated4 ,the cellulose obtained by this treatment is but #b-c per cent42 this number1 however1 represents only the amount which has survived a treatment which we know to be destructive to cellulose4 ,if1 on the other hand1 cork be resolved by treatment with sodium sulphite solution at #ajjlb4 pressure1 or #aff ,c4 7#cca ,f471 a soft mass is obtained1 preserving the structural features of the original cork1 until subjected to slight pressure1 when it falls to a cellular mass4 ,from this1 cellulose is isolated by any of the less drastic processes above described1 and is found to amount to #i-aj of the original cork4 ,as in ligno-cellulose1 we have evidence of a transition from cellulose to the tannins1 so in cork and cuticular tissue we have evidence of the metamorphosis of cellulose into fats1 a fact indicated in the term adipo-cellulose1 which we have applied to the compound celluloses constituting these protective plant tissues4 ,this metamorphosis is doubtless a very complex process1 and would appear to involve the formation of tannins also1 at least as a subsidiary result4 ,still1 the essential feature of the change is the production of the peculiar fat-like substances which have been described2 and with due regard to the limitation pointed out1 the views here advanced represent the results of the investigations of the subject as far as they have proceeded4 ,it may be observed that the general characteristics of the #bh adipo-celluloses as of the ligno-celluloses are those of a complex aldehyde4 ,pecto-,cellulose4--,the compound cellulose described under the names adipo-cellulose and ligno-cellulose have this feature in common1 that they are richer in carbon than cellulose4 ,on the other hand there is a large number of cellulosic tissues which contain in the aggregate less carbon1 i4e41 in which the cellulose is combined or mixed with substances of lower carbon percentage than itself4 ,such tissues1 or rather the substances which compose them1 are resolved by simple treatment with dilute alkaline solutions into insoluble cellulose1 and soluble bodies of the pectic class4 ,thus the purified bast of the ,russian flax1 i4e41 the raw flax1 is found to contain-- #dcg per cent4 ,c4 #ei ,h4 ,on boiling with an alkali it loses in weight about #bj per cent41 the substance dissolved being identical in properties with ,frmy's pectic acid1 a substance containing #db per cent4 ,c and #d4h per cent4 ,h ,c#af;,h#bb,o#ae4 ,many other bast fibres1 as well as cellulose tissues1 exhibit similar properties1 and although this branch of the subject has been but little investigated1 there is sufficient evidence for constituting a special class of compound celluloses under this term1 pecto-cellulose1 having properties indicated in the type selected above4 ,in addition to pectic acid there exists in1 or can readily be obtained from certain plants1 a series of bodies of a similar nature1 such as pectose1 pectin1 parapectic acid and metapectic acid4 ,the most important of these are pectic acid and metapectic acid4 ,pectic acid1 though it rarely exists ready-formed in the plant1 can readily be obtained from it by the action of weak alkalis4 ,it is best procured by boiling the pulp of turnips with a #aj per cent4 solution of sodium carbonate for about half an hour4 ,if an acid be added to the filtered liquid1 pectic acid is precipitated as a transparent colourless jelly1 which #bi dries up to a transparent horny mass4 ,by the prolonged action of alkalis or acids1 pectic acid is converted into metapectic acid 7,c#h;,h#ad,o#i71 which may be obtained as a syrupy1 strongly acid liquid4 ,from what we know of the properties of the members of the pectic group1 and therefore of the pecto-celluloses1 it will be readily seen that the latter are very liable under the action of alkalis to undergo conversion into soluble derivatives4 ,conversely1 a study of the action of alkalis upon plant substances1 enables us to determine to what extent the latter partake of the nature of the pecto-cellulose1 the importance of which to the practical paper maker we need hardly point out4 ,for a further development of this idea 7see p4 #dc74 #cj ,,chapter ,,ii4 ,,physical ,,structure ,,of ,,fibres4 ,we now have to treat of the fibrous raw materials from the point of view of form or structure1 which is1 of course1 a very important factor in determining the quality of the paper or other fabric into which they are manufactured4 ,it is sufficiently evident that the strength of paper is primarily due to the cohesion of its constituent fibres4 ,when paper is torn1 the edges present a fibrous appearance1 and observation teaches us that1 other things being equal1 the greater the manifestation of fibrous structure the stronger will be the paper4 ,if a paper be thoroughly wetted1 its tensile strength is reduced to a minimum1 and if subjected to a slight strain we get1 not a tearing1 but a pulling asunder of the fibres4 ,if this be performed under a lens1 the structure of the paper is more clearly seen1 and it will be appreciated to what extent the qualities of a paper are the aggregate of the qualities of its constituent fibres4 ,a more careful dissection of the paper shows that these fibres1 which are the ultimate fibres of the plant1 as distinguished from the bundles of these1 or filaments1 which the spinner employs1 are interlaced in all directions4 ,to produce this effect of interweaving1 and to insure that uniformity which is an essential feature of good paper1 we have among others the following contributory causes3 7#a7 the deposition of the fibres from suspension in water2 7#b7 the composition of the pulp with regard to the reduction of the fibrous bundles1 and the isolation of the individual fibres2 and 7#c7 the structure of these ultimate fibres4 ,it is with the last that we are chiefly concerned at present4 ,to convey a general notion of the influence of the structure #ca of fibres upon fabrics1 we shall with advantage travel outside our immediate province to consider briefly the woollen and silk manufactures in relation to this point4 ,wool is1 as we know1 a discontinuous fibre1 and its structure is that represented in ,fig4 #a1 the most conspicuous feature being its broken surface1 consisting apparently of imbricated scales4 ,illustration3 ,,fig4 #a4 ,the silk fibre1 on the other hand1 is a dual cylinder1 spun by the worm in a continuous length1 and with a perfectly smooth surface4 ,now1 it would not be to our purpose to point out that in starting from a discontinuous simple fibre1 to produce a continuous1 therefore necessarily compound one1 a very different treatment or process of spinning is required from that which the opposite condition renders practicable4 ,we will rather consider the influence of structure upon materials manufactured from these fibres4 ,it is obvious that the wool fibres1 brought into contact with one another1 tend to interlock2 whereas silk fibres if rubbed or pressed together1 simply slide over one another2 the result in the fabric is by multiplication of the effect1 a shrinking or contracting in length and breadth4 ,this interaction of the fibres1 and the phenomena to which it gives rise1 is known as the felting of wool and woollen goods2 this tendency1 for the contrary reason1 is not seen in silk fabrics4 ,the production of paper from a disintegrated fibrous mass or pulp introduces similar considerations4 ,that paper will be the stronger in which the constituent fibres are the better felted1 and the degree in which felting takes place will depend to a great extent upon the form or microscopic peculiarities of the fibres4 ,this is only one of the more obvious inferences to be drawn from the structure of fibres to the qualities of the papers which they compose4 ,other #cb equally important practical bearings will be seen to attach to the microscopic study of our fibrous raw materials1 and to the consideration of this branch of the subject1 we now ask the careful attention of the student4 ,,microscopical ,,examination4--,under the head of 8,microscopic ,features0 we must include everything which has to do with the structure of the vegetable fibres1 as well as their organisation and distribution in the plant4 ,in the analysis of 8organised0 structures we employ the two methods4 7#a7 of dissection2 7#b7 examination by means of the microscope2 in other words1 we first isolate the part under investigation by a mechanical process and then proceed to the optical resolution or analysis of the part4 ,having by analysis acquired a knowledge of the parts1 we study their mutual relations in the structure they compose--we integrate our knowledge1 so to speak--by means of sections of the structure1 cut so as to preserve the cohesion of the parts in section1 and yet in so fine a film as to appear under the microscope to be virtually a plane surface4 ,these points are illustrated in the drawings given4 ,it is impossible for us to deal specially with the subject of the microscope and its manipulation4 ,the microscope1 as a revealer of natural wonders is one thing2 as an instrument of scientific discovery1 quite another4 ,for the latter1 the student must train himself by systematic work1 and should especially concentrate his attention upon some one branch of natural history1 however restricted4 ,we shall assume1 in our treatment of the subject1 a knowledge of the microscope as an instrument of research1 such as can be easily acquired in a few weeks of work under the guidance of a teacher or of one of the excellent manuals which now abound4 ,we also assume a certain acquaintance with the elements of vegetable physiology1 which it will be seen is necessary for a full grasp of the subject4 ,such an acquaintance1 also1 may be easily acquired1 under direction1 in a few weeks of work4 ,illustration3 ,,fig4 #b4 ,illustration3 ,,fig4 #c4 ,we have before alluded to the differences presented by #cc mono and dicotyledonous stems in regard to the distribution of their fibrous constituents4 ,in illustration of this1 we may cite ,figs4 #b1 #c1 which represent1 7#b7 a section of the aloe1 7#c7 a section of the jute plant4 ,the available fibres are in 7#b7 the fibro-vascular bundles 7f71 which are irregularly distributed throughout the main mass of cellular tissue1 and #cd in 7#c7 the bast fibres 7f71 which constitute a definite and separate tissue4 ,we have already alluded to the practical consequences of this typical difference of distribution1 in regard to processes of separating these fibres on the large scale4 ,this process we have explained is necessarily simpler in the case of a fibrous tissue1 definitely localised2 and this may be demonstrated by a superficial examination of a young branch of an exogen4 ,as we know1 the bark tissues are easily stripped from the underlying wood4 ,if now we work up the former in a mortar1 with a little water1 we soon perceive the separation of the compound tissue into cellular matter on the one hand and fibres1 the latter being more or less long and silky1 according to the plant from which isolated4 ,they vary in length from one millimetre to several centimetres1 and are aggregated together in the plant in such a way as to constitute bundles1 often of very considerable length2 the general arrangement being comparable with that of the tiles in the roof of a house4 ,it is important to distinguish the fibre-bundles from the elementary or normal fibres1 and to this end they are designated by the term filament4 ,bast fibres are flexible and fusiform1 terminating gradually in a point at either end1 as represented in ,fig4 #d2 bast filaments1 built up of these fibres1 containing often as many as twelve in the bundle1 are usually cylindrical1 but exhibit the widest differences in regard to the aggregation1 in degree as well as number of their constituents4 ,it is obvious that while the spinner has to do with these filaments1 the paper maker works up the ultimate fibre constituents or fibres4 ,it is also an obvious corollary from this distinction that a fibrous material which from 8weakness0 is unavailable for textile application1 may yet be perfectly 8strong0 from the paper maker's point of view2 in other words1 the individual fibres may be strong1 but have little cohesion in the filaments4 ,as we proceed1 the student will see more and more the practical bearings of this branch of the study1 and will perceive the inferences to be drawn from the investigation of #ce minute relationships to manufacturing processes and their products4 ,illustration3 ,,fig4 #d4 ,we shall say but little as to the necessary equipment4 7#a7 ,a dissecting microscope1 for dissecting under a lens1 magnifying the object to #dj or #ej diameters4 7#b7 ,an ordinary student's microscope with lenses for magnifying to #ajj and #cjj diameters4 ,this is adequate to the work1 though of course1 it may be an advantage in certain cases1 to be provided with higher powers4 7#c7 ,a glass slide1 carrying an engraved scale of centimetres and millimetres for measuring the lengths of objects1 and a micrometer1 divided into #a_/aj mm4 for measuring diameters4 ,it is also important to be able to determine the degree of enlargement under any particular combination of lenses1 and for this purpose to possess a micrometer eye-piece1 with a millimetre scale divided into hundredths4 7#d7 ,an effective microtome and the usual mounting accessories4 ,a very important feature in the diagnosis of fibres1 more especially in regard to the composition of the fibre substances1 is the effect produced by treatment with various reagents4 ,certain of these reactions we have already #cf indicated4 ,we shall now give the details of composition of the several solutions which will be required4 ,neutral ,mounting ,solutions4--,it is advantageous in mounting transparent objects to employ a solution of the same refractive power as the substance itself4 ,for this purpose1 pure glycerin or a syrupy solution of calcium chloride may be employed2 it is expedient to mix with either reagent a small proportion of acetic acid4 ,the designation 8neutral0 has reference to the fact that these reagents are without sensible action on the fibres4 ,iodine ,solution4--,we have previously described the preparation of a solution1 giving the characteristic blue reaction with cellulose directly4 ,it is1 however1 often preferable to bring about this colouration in another way1 and the following are the solutions employed3--#a gramme of potassium iodide is dissolved in #ajj cc4 water1 and the solution is saturated with iodine2 it is preserved in stoppered bottles1 containing a few fragments of the element1 so as to keep up the saturation of the solution4 ,the accessory solution1 dilute sulphuric acid1 which is employed to determine the reaction between the cellulose and the iodine1 is prepared as follows3--#b volumes of concentrated glycerin are mixed with #a volume water1 and to the mixture an equal volume of oil of vitriol 7#agh sp4 gr471 is slowly added1 so as to prevent as far as possible a rise of temperature4 ,the effect of the glycerin is very remarkable in preventing the distortion of the objects under the action of the acid1 which in other respects remains uninfluenced4 ,by way of verification of this iodine test1 which is somewhat capricious1 it is advisable to test the reagents with a standard substance4 ,the best for the purpose is a linen yarn which has been partially bleached4 ,under the action of the reagents the fibres composing this yarn1 which must1 of course1 be suitably 8teazed out0 for mounting1 are coloured a light blue1 the centre1 however1 showing a yellow line1 #cg marking the distribution in the interior canal of a non-cellulose fibre constituent4 ,should these effects not appear1 it may be concluded that the acid requires to be strengthened4 ,on the other hand1 too great a concentration is equally to be avoided2 it is evidenced by causing a distortion of the fibre1 easily recognised by comparison with the fibre mounted in a neutral medium4 ,chlorine ,water4--,one of the most characteristic reactions of lignose1 or lignified cellulose1 is that of combining with chlorine4 ,the reaction of the chlorinated derivatives with sodium sulphite solution1 is an important feature in the microscopic diagnosis of lignified fibres and cells4 ,the reagent is prepared by dissolving chlorine to saturation in water4 ,the sodium sulphite solution is prepared by dissolving the crystallised salt in #bj parts distilled water4 ,aniline ,sulphate ,solution4--,with this reagent lignose gives a characteristic deep yellow colouration4 ,a convenient strength is a #b per cent4 solution of the salt4 ,the colour is more quickly developed if the reagent is acidified2 a few drops of sulphuric acid should therefore be added4 ,solutions of the ,aniline ,colours4--,some of these are of importance in enabling the microscopist to differentiate plant tissues4 ,the 8affinities0 of the fibre substances for these are very various in kind and intensity4 ,the phenomena of staining cannot be adequately treated in our histological scheme1 which is necessarily very restricted4 ,we1 therefore1 merely mention the more important colours which are used in staining1 viz41 magenta1 methylene blue1 eosine1 diphenylamine blue4 ,a convenient strength is a solution of #a in #bjjj4 7,see also p4 #dc47 ,the employment of the aniline sulphate solution1 as well as of the solutions of the aniline colours1 presents no difficulties1 and therefore needs no detailed description4 ,the former strikes a more or less deep yellow with lignose2 the aniline colours stain or dye the tissue or fibre more or less deeply1 according to its composition1 and1 as it is a reciprocal action1 #ch according also to the composition of the colouring matter4 ,in following up this subject1 the student will require to consult works on vegetable histology4 ,preparation of the objects4--,the necessary preliminary to the examination of the fibres themselves is their isolation4 ,this is accomplished either by means of the dissecting microscope1 or more roughly1 according to circumstances4 ,having obtained the filaments1 they are boiled in a #aj per cent4 solution of sodium carbonate until sufficiently softened to yield easily to the 8teazing0 needles4 ,in certain cases the boiling must be supplemented by trituration in a mortar2 this1 or some similar operation1 is especially necessary when the fibres are embedded in a mass of cellular tissue 7parenchyma7 e4 g4 in the fibro-vascular bundles of monocotyledons4 ,sections of the filaments are prepared by cutting in a microtome1 the filaments being previously agglutinated into a stiff bundle by means of any of the usual stiffening solutions1 and after drying1 embedded in wax in the usual way4 ,sections of fresh stems and tissues are cut with a 8section0 razor4 ,having prepared the objects1 their examination under the microscope necessarily divides itself into3--7#a7 the determination of external features2 7#b7 the diagnosis of chemical composition4 ,the fibres themselves will be individually considered in regard to microscopic features4 ,there is one aspect of these structural features1 however1 which admits of more general treatment1 and in respect to this we may anticipate with advantage1 viz41 the dimensions or simple elements of form4 ,the importance of the determination of the length and diameter of both filaments and fibres will be readily appreciated by an inspection of the following table1 in which the numbers are given for several of the more important4 ,a careful study of this table in relation to the application of these several fibres1 will show that the correlation of the latter with these ultimate dimensions is close and essential4 #ci ,,table ,,of ,,lengths ,,of ,,raw ,,fibres 7,,filaments7 ,,and ,,dimensions ,,of ,,constituent ,,cells ,,and ,,fibres4 ---------------------------------------- ---------------------------------------- ---------- ,diameter of ,cells4 ,length of ,length of -------------------- ,filament4 ,fibres4 ,extreme4 ,normal4 ---------------------------------------- ---------------------------------------- --------- cm4 cm4 #a_/ajjmm4 #a_/ajjmm4 ,a4 ,seed hairs4 ,filaments composed of individual cells4 ,cottons4 ,gossypium barbadense 7,sea ,island7 #dje #dje #aib-bgi #beb ,gossypium acuminatum #bhd #bhd #bja-bii #bid ,gossypium arboreum #bej #bej #bjj-cgh #bii ,bombax heptaphyllum #b-c #b-c #ai-bi 44 ,b4 ,bast fibres4 ,filaments or fibre bundles1 made up of individual fibre-cells aggregated together4 ,flax4 ,linum usitatissimum #bjadj #bj-dj #ab-be #af ,hemp4 ,cannabis sativa #ajj-cjj 44 #ae-bh #ah ,china ,grass4 ,boehmeria nivea 44 #bbj #dj-hj #ej ,ramie4 ,boehmeria tenacissima 44 #hj #af 44 ,jute4 ,corchorus capsularis #aej-cjj #h #aj-bj #af ,corchorus olitorius #aej-cjj #h #af-cb #bj ,paper mulberry4 ,broussonetia papyrifera 44 #g-ba 44 #cf ,linden bast4 ,tilia grandifolia 44 #aa-bf 44 #ae ,c4 ,fibro-vascular bundles ,new ,zealand ,flax4 ,phormium tenax #hj-aaj #be-ef #h-ai #ac ,aloe4 ,aloe perfoliata #dj-ej #ac-cg #ae-bd 44 ,esparto4 ,stipa tenacissima #aj-dj #je-ai #i-ae 44 ---------------------------------------- ---------------------------------------- --------- ,a very important point in the diagnosis of a raw material1 and next in order of treatment1 is the degree of purity of the substance1 in so far as this is related to structure4 ,the fibres may be associated with cellular tissue1 or with cellular debris1 if they have undergone the retting process or other treatment for separation2 or with 8encrusting and intercellular substances0 in various proportions4 ,in the latter case the association with the fibres is usually much more intimate2 they are in fact essential constituents of the fibre bundles #dj 7bast-fibres1 fibro-vascular bundles71 whereas the former we may regard as 8foreign matter40 ,we may1 however1 distinguish between the normal incrustation of the fibre-cells1 and such an incrustation of the filaments as would be described as a loose adhesion of non-fibrous matter4 ,the latter is seen in such tissues as the bast of the adansonia1 and the fibro-vascular bundles of the aloes4 ,these are points with which observation alone can familiarise the student2 as experience grows he will find it increasingly easy to follow general distinctions1 and in proportion as he uses his own faculties1 so he will be able to generalise for himself4 ,he will find this equally true of the second section of the microscopic examination1 i4e41 the micro-chemical diagnosis of fibres4 ,under this head is included the observation of the behaviour of fibres towards the various reagents above described4 ,in addition to their microscopical employment it is useful to note their effect on fibres in the gross1 both in their natural state and after treatment with bleaching agents4 ,in applying the iodine reaction1 attention must be paid to the following details of manipulation4 ,place the object 7dry7 upon the glass slide1 moisten with a few drops of the iodine solution1 cover with a glass slip and examine under the microscope4 ,note the effects1 which are those of the iodine alone4 ,then remove the iodine solution by means of blotting paper1 and introduce the sulphuric acid by the method of 8irrigation40 ,the colouration of the cellulose 7blue-violet7 is immediate2 it has the effect moreover1 of bringing out more clearly a number of the structural details of the fibre4 ,we have already treated of the resolution of the raw fibres into cellulose and non-cellulose constituents by processes which convert the latter into soluble derivatives4 ,the student will derive much instruction from following up the attendant structural disintegration with the aid of the microscope4 ,the chemical dissection of lignified fibres by the alternate action of bromine water and alkalis1 should be studied by mounting specimens of the fibre at all stages and #da carefully noting all the changes which occur4 ,the more drastic action of chlorine should also be studied by mounting the chlorinated fibre 7in water7 and then irrigating with the alkaline solvent 7caustic alkali or sulphite7 and noting the stages in the completion of the disintegration4 #db ,,chapter ,,iii4 ,,scheme ,,for ,,the ,,diagnosis ,,and ,,chemical ,,analysis ,,of ,,plant ,,substances4 ,it will be convenient at this point to present to the reader a general scheme for the chemical analysis of fibrous raw material4 ,we have already discussed 7p4 #d7 the methods for the determination of cellulose in fibrous substances4 ,this is to the paper-maker the most important constituent1 and is that upon which his calculations of the value of a raw material are based4 ,not only1 however1 is it of the greatest importance for him to be able accurately to determine the amount of cellulose1 but it is necessary to be able to form some idea of the nature of the cellulose and also the ease with which it can be obtained from the fibre4 ,this latter point can only be properly established by direct trial of the fibre under the conditions existing in the factory4 ,it should also be borne in mind that these conditions influence to a considerable degree the amount of cellulose1 actually obtained in practice1 and that therefore the percentage shown by a careful determination in the laboratory should only be taken as an indication of the amount likely to be realized4 ,the student will be able1 from what has been said before of the properties of the different celluloses1 to apply his knowledge to a determination of any particular specimen4 ,in order to supplement this knowledge1 it may be well at this particular point to cite the chief results of an investigation bearing upon this point by ,webster 7,chem4 ,soc4 ,journ41 #ahhc1 p4 #bc74 ,his method of investigation consisted in 7#a7 estimating #dc the cellulose2 7#b7 determining the loss sustained by the fibre when boiled for #e minutes1 and also for #fj minutes1 with an alkaline solution 7caustic soda #a per cent4 ,na#b,o71 the former being taken to represent the purely solvent action1 the difference between the two amounts being an indication of the degrading action of the soda2 7#c7 determining the ultimate composition 7,c ,h and ,o7 of the fibre substance4 ,it should be observed that the specimens were carefully averaged and purified by boiling in glacial acetic acid and in alcohol4 ,on carefully considering the following table it will be seen that the chief points brought out by ,webster's investigation are 7#a7 the association of a low carbon percentage with pectous properties and considerable degrading action on long boiling in alkali4 ,the bearing of this will be better understood in connection with a discussion of the properties of pectic acid 7p4 #bh7 and the oxycelluloses 7p4 #ac74 7#b47 ,the influence of the composition of the original fibre on the isolated cellulose4 ,the solutions of aniline sulphate and of the aniline colours give valuable aid in a diagnosis of plant substances4 ,webster observed1 as was to be expected1 that the yellow colour produced could be taken as an indication of the amount of lignification1 those fibres which were of a pectous nature showing little or no colour4 ,on the other hand1 when the fibres were treated with a neutral solution of the so-called alkali-blue it was found that the converse took place1 highly pectous fibres being dyed much more deeply than those which were lignified4 7,compare the action of aniline colours on oxycellulose1 p4 #aa47 ,if the student require more precise knowledge of the nature of a fibrous material than that afforded by a determination of the cellulose1 the following method of analysis will prove of service4 #dd ,,fibro-,,vascular ,,bundles ,,of ,,monocotyledonous ,,plants4 ---------------------------------------- ---------------------------------------- -------- ,ananassa ,musa ,phormium ,agave ,yucca sativa paradisiaca tenax ,americana4 gloriosa4 7,pine ,apple47 7,manilla74 7,new ,zealand ,flax74 ---------------------------------------- ---------------------------------------- -------- #a4 ,yield of cellulose #hab #hjh #gfc #fbh #hfc by chlorine method #b4 ,character of ,fibres free4,fibres free4 ,fibres ,fibres ,fibres isolated cellulose agglutinated4agglutinated4 partially agglutinated4 #c4 ,loss in boiling #a #ii #ade #if #ahf #eh per cent4 caustic soda 7#e minutes7 #d4 ,ditto 7#fj minutes7 #adf #afe #aij #cag #ii #e4 ,ash #aj #ac #aj #af #ji #f4 ,elementary ,c4 #dei 44 #dbe #dbf #ddd composition ,h4 #fa 44 #ef #ef #ei #g4 ,lignified or ,lignified4 ,lignified4 ,lignified4 ,lignified4 ,lignified4 otherwise4 ,aniline sulphate reaction ---------------------------------------- ---------------------------------------- -------- ,,bast ,,fibres ,,of ,,dicotyledonous ,,plants4 ---------------------------------------- ---------------------------------------- -------------------- ,urtica ,crotolaria ,linum ,corchorus ,boehmeria heterophylla juncea ,hibiscus usitatissimum capsularis ,puya4 7,nilgherry 7,sunn74 strictus4 7,flax74 7,jute74 ,nettle74 ---------------------------------------- ---------------------------------------- -------------------- #a4 ,yield of cellulose #hch #iej #gfi #fcj #hbj #gej by chlorine method #b4 ,character of ,fibres ,fibres free4,fibres free4 ,fibres ,fibres free4 ,fibres free4 isolated cellulose partially partially agglutinated4 agglutinated4 #c4 ,loss in boiling #a #aef #bf #ec #acg #gh #agb per cent4 caustic soda 7#e minutes7 #d4 ,ditto 7#fj minutes7 #bda #gc #ajg #bee #aff #ahf #e4 ,ash #cg #aj #ji #bj #ag #aa #f4 ,elementary ,c4 #dah #dbi 44 44 #dcg #dga composition ,h4 #fj #ei 44 44 #ei #ei #g4 ,lignified or ,not ,not ,lignified4 ,lignified4 ,not ,lignified4 otherwise4 ,aniline lignified4 lignified4 lignified4 sulphate reaction ---------------------------------------- ---------------------------------------- -------------------- ,about two grms4 are taken and dried at #aaj-aae ,c4 until the weight remains constant3 the loss represents water4 ,the fibre is then treated with a hot mixture of benzene and alcohol1 dried as before and weighed3 the loss is fat1 wax1 #de c4 ,the residue from this treatment is then repeatedly exhausted with boiling water and again dried at #aaj-aae ,c4 and weighed3 the loss is put down as aqueous extract4 ,the exhausted fibre is then treated for cellulose by either of the methods given on p4 #ai4 ,the ash is determined in a separate portion4 #df ,,chapter ,,iv4 ,,an ,,account ,,of ,,the ,,chemical ,,and ,,physical ,,characteristics ,,of ,,the ,,principal ,,raw ,,materials4 ,this chapter contains the results obtained from an investigation of the different plant fibres by the methods indicated in the two previous chapters4 ,in the following table the fibres are classified according to the reactions which they give with iodine solution4 ,,classification ,,of ,,plant ,,fibres ,,according ,,to ,,their ,,colour ,,reaction ,,with ,,iodine ,,solution 7,v,,tillart74 ,a4 ,b4 ,c4 ,seed ,hairs4 ,dicotyledonous ,monocotyledonous ,bast ,fibres4 ,fibres corresponding to ,bast ,fibres4 ,blue reaction ,cotton4 ,linen4 ,straw4 ,hemp4 ,esparto4 ,china grass4 ,pine apple4 ,paper mulberry ,sunn4 ,yellow reaction ,jute4 ,new ,zealand flax4 ,yucca4 ,hibiscus4 ,aloe4 ,manilla hemp4 ,class ,a4 ,,cotton4--,genus1 ,gossypium4 ,order1 ,malvace4 ,seed hairs1 consisting of ultimate fibres4 ,length1 #bj-dj c4m41 diameter1 #jjab-jjcg mm4 ,mean ratio1 #abej4 ,illustrated in ,fig4 #e3 a1 sections2 b1 longitudinal views2 c1 ends2 mag4 #cjj4 ,microscopic features4--,fibres simple1 opaque1 flattened1 always more or less twisted upon itself1 side wall membranous1 showing stri4 #dg ,sections4--,simple1 oval1 irregular1 central cavity often containing granules4 ,micro-chemical reaction4--,blue with iodine solution4 ,illustration3 ,,fig4 #e4 ,general chemical characteristic4--,pure cellulose basis with slight admixture of colouring matters1 c4 ,,composition ,,of ,,raw ,,fibre4 ,church4 ,mller4 ,cellulose #iaae #iace ,fat #jea #jdj ,aqueous extract 7containing nitrogeneous substances7 #jfg #jej ,water #gef #gjj ,ash #jaa #jab ,cuticular substance 7by difference7 44 #jfc ,e4 ,schunck in his investigation of cotton bleaching 7,chem4 ,news1 #ag1 p4 #aa7 finds that in boiling with sodium carbonate solution the fibre loses #e per cent4 in weight4 ,some portion of the dissolved substances is precipitated on acidifying and is found to contain a wax1 brown resinous and colouring matters1 and pectic acid4 #dh ,forms in which employed4--,fibrous refuse from the decortication of the seeds2 spinning waste1 threads1 rags1 new and old4 ,class ,b4 ,,flax4--,genus1 ,linum4 ,order1 ,linace1 ,bast fibres and filaments4 ,length of fibres1 #be-cj mm42 diameter1 #jjb mm41 ratio1 #abjj4 ,illustrated in ,fig4 #f3 a1 sections of the fibres1 isolated and in groups2 b1 the fibres viewed longitudinally1 one showing the creases produced by repeated bending2 c1 ends2 a1 sections of fibres situated near the butt of the plant2 mag4 #cjj4 ,illustration3 ,,fig4 #f4 ,microscopic features4--,fibres transparent1 regular1 with tapered ends1 side walls thick1 consequently central canal small1 smooth externally1 sometimes slightly striated4 ,filaments easily split up into fibres4 ,sections4--,polygonal1 regular1 angles more or less acute1 lumen represented by point2 slight indications of concentric arrangement of fibre substance4 ,micro-chemical reaction4--,blue with iodine solution4 ,general chemical characteristic4--,pecto-cellulose4 ,composition of raw fibre4--,this varies with the different species1 and is doubtless also influenced by variations in the #di processes of retting4 ,the following are the analyses of two samples of ,belgian flax 7heckled73-- ,mller4 ,cellulose #haii #gjee ,fat and wax #bcg #bcd ,aqueous extract #cfb #eid ,pectous substances #bgb #ibi ,water #hfj #ajef ,ash #gj #acb ,the chemistry of the flax fibre has been investigated by ,kolb4 ,forms in which employed4--,scutching refuse1 spinning waste1 threads1 rags1 new and old4 ,,hemp4--,cannabis sativa4 ,order1 ,cannabinac4 ,bast fibres3 length1 #bb mm42 diameter1 #jjbb mm42 ratio1 #ajjj4 ,illustrated in ,fig4 #g3 a1 a1 sections of groups of fibres of the first and second zone respectively2 b1 fibres seen longitudinally2 c1 ends2 mag4 #cjj4 ,illustration3 ,,fig4 #g4 ,microscopic features4--,compact bundles4 ,fibres show stri and fissures1 and often fibrill1 detached or adherent4 ,the central canal almost obliterated1 ends of fibres large and flattened4 ,the bundles show fine transverse markings4 #ej ,section4--,well marked concentric zones of fibre substance1 irregular in outline4 ,micro-chemical reaction4--,blue and yellow reaction with iodine solution1 the joint result showing green colouration4 ,general chemical characteristic4--,pecto-cellulose4 ,,composition ,,of ,,raw ,,fibre 7,,italian ,,hemp74 ,mller4 ,cellulose #ggac ,fat and wax #ee ,aqueous extract #cde ,pectous substances #ibe ,water #hhj ,ash #jhb ,forms in which employed4--,scutching refuse1 spinning waste1 threads1 cuttings and rope ends4 ,,sunda or ,,sunn ,,hemp4--,genus1 ,crotalaria4 ,order1 ,papilionace4 ,bast filaments3 length1 #g-h mm42 diameter1 #jjc2 ratio1 #bjj 3 #a4 ,microscopic features4--,generally similar to those of hemp4 ,micro-chemical reactions4--,with iodine various1 from blue to yellow4 ,with aniline sulphate1 slight yellow4 ,general chemical characteristics4--,pecto-cellulose 7with some ligno-cellulose74 ,the following are the results of analysis of the raw fibre 7,h4 ,mller73-- ,cellulose #hjja ,fat and wax #ee ,aqueous extract #bhb ,pectous substances #fda ,water #ifj ,ash #jfa ,this fibre1 exported from ,india and the ,sunda ,islands1 has found employment in ,spain and ,portugal1 but up to the present has not been adopted to any extent in other parts of ,europe4 ,,china ,,grass1 ,,rhea1 ,,ramie4--,genus1 ,bhmeria4 ,order1 ,urticace4 ,bast filaments3 length1 #abj mm42 diameter1 #jje2 ratio1 #bdjj 3 #a4 ,illustrated in ,fig4 #h3 a1 section of a #ea bundle of fibres2 b1 a fibre seen longitudinally2 c1 ends2 mag4 #cjj4 ,illustration3 ,,fig4 #h4 ,microscopic characteristics4--,irregular in form and length2 often conspicuous in respect of latter 7see ,table1 p4 #ci72 fibre sometimes cylindrical1 either smooth or striated1 sometimes flattened2 central canal well developed1 often containing granules2 extremities of fibres rounded1 spatulated or lance-shaped4 ,sections marked by numerous concentric layers1 often showing radiating stri4 ,micro-chemical reaction4--,blue to violet1 with iodine solution4 ,general chemical characteristics4--,pecto-cellulose4 ,composition of raw fibre 7,h4 ,mller73-- ,cellulose #gehc #fbej ,fat and wax #bj #jef ,aqueous extract #fbi #igf ,pectous substances #fjg #abjj ,water #hgd #iee ,ash #bhg #efc ,forms in which employed4--,up to the present the price has been prohibitive4 ,has been the subject of successful #eb experiments2 imparts great tensile strength to paper4 ,the portions available will be as in flax4 ,,common ,,nettle4--,urtica dioica4 ,order1 ,urticace4 ,bast filaments3 length1 #bg mm42 diameter1 #jje2 ratio1 #eej4 ,microscopic characteristics similar to the above4 ,the fibres of this plant were1 in the olden times1 separated in the same way as flax1 and worked up into cloth4 ,at present it has no practical interest to the paper-maker1 but deserves attention at the hand of the student1 as the most easily accessible for the purpose of study4 ,it is1 moreover1 possible that1 under cultivation1 it may yet become a source of raw material for paper-making4 ,,jute4--,corchorus4 ,order1 ,tiliace4 ,bast3 length1 #b mm42 diameter1 #jjbb2 ratio1 #ij4 ,illustrated in ,fig4 #i3 a1 section of bundles of fibres2 b1 fibres seen longitudinally2 c1 ends2 mag4 #cjj4 ,illustration3 ,,fig4 #i4 ,microscopic features4--,compact bundles2 fibres smooth4 ,micro-chemical reactions4--,yellow brown1 with iodine2 yellow1 with aniline sulphate2 bright yellow1 with chlorine water2 changed to carmine by treatment with sodium sulphite solution4 #ec ,general chemical characteristic4--,ligno-cellulose4 ,the chemistry of jute as the type of ligno-cellulose has been treated on p4 #ag4 ,composition of raw fibre 7,mller73-- ,cuttings or ,butts4 #ast ,quality4 7,root ends74 ,cellulose #fcgf #fjhi ,fat and wax #jch #dd ,aqueous extract #ajj #chi ,non-cellulose1 or lignin #bdcb #bjih ,water #ihf #abdj ,ash #fh #adj ,forms in which employed4--,threads1 butts1 bagging4 ,,bast ,,tissues4--,we have alluded1 in our opening remarks1 to the broad division of the bast of exogen or dicotyledonous plants into coherent and non-coherent tissues4 ,we have now considered the more important of the latter1 and we find that they are obtained from the stems of annuals4 ,we find also that while they constitute a tissue1 in the sense of being definitely localised1 the constituent fibres are disposed in parallel series of independent bundles or filaments1 which are isolated by a mechanical operation after the whole stem has undergone the preparatory retting process4 ,in exogens of longer and larger growth1 the bast1 as might be expected1 becomes a coherent compound tissue1 which is1 in many cases1 easily detached from the underlying wood4 ,we shall mention three of these as receiving very important applications2 though only one has been applied to any extent by the papermakers of this country4 ,this1 which we shall consider first1 is the bast of the ,adansonia digitata1 or baobab1 a tree which flourishes in the tropical regions of the ,west ,coast of ,africa4 ,it is exported chiefly from ,loanga1 in the form of fibrous lumps of a brown colour4 ,these are seen to be composed of a network of bast bundles1 which are but slightly coloured1 intersected by medullary rays of a dark brown colour4 ,the microscopic features of the fibre are those which are generally characteristic of the bast of exogens2 we do not know that we could cite any whereby it could be identified with certainty4 #ed ,the fibres give a yellow colouration with aniline sulphate1 but they contain only a small proportion of lignose4 ,the following are the results of analyses of this bast3-- ,cellulose #dice #ehhbg ,fat and wax #jid #jda ,aqueous extract #aceg #gjh ,pectous substances #aije #aeai ,water #ajij #acah ,ash #fai #dgb ,footnote #g3 ,made up of #acge cellulose from medullary tissue1 #dejg cellulose of fibres4 ,linden ,bast 7,tilia ,europa7 is the raw material employed in the manufacture in ,russia of the mats so largely used in this country for wrapping furniture and heavy goods1 and also by gardeners for a variety of purposes4 ,one of the features of this bast is the strong cohesion of the fibres in the bundles or filaments4 ,they are resolved1 but with difficulty1 on long boiling1 with a solution of carbonate of soda1 the soluble products being of a mucilaginous nature4 ,this bast has not been applied to any extent by the paper-makers of this country4 ,bast of the ,paper ,mulberry 7,broussonetia papyrifera74--,this product deserves mention1 not from its importance to the ,european papermaker1 but because of its application to the manufacture of the peculiar papers of the ,chinese and ,japanese4 ,the special features of this1 and the other basts which are similarly employed in these countries--,edgworthia papyrifera1 ,broussonetia kaempferia1 are 7#a71 the ease with which the coherent fibrous tissue is separated from the parenchymatous tissue which accompanies it2 7#b71 its comparative freedom from medullary rays2 7#c71 the great length and fineness of the fibres4 ,these properties conduce to its ready conversion into a well felted paper1 of great tensile strength and remarkable softness4 ,class ,c4--,these are whole stems of monocotyledonous annuals4 ,the isolation of fibres for paper-making from these plants depends upon a chemical process of resolution2 the #ee pulp obtained is1 therefore1 a complex of the various orders of cell-fibres contained in the plant4 ,while the pulp consists for the most part of the vessels of the fibro-vascular bundles1 it contains in addition the serrated cuticular cells which are so characteristic of this group4 ,they therefore present a general similarity in microscopic features2 there are1 however1 certain individual characteristics1 such as the form and dimensions of particular cells1 which serve for the identification of the various pulps4 ,where such occur they will be indicated4 ,illustration3 ,,fig4 #aj4 ,,esparto4--,stipa tenacissima and ,lygeum ,spartum4 ,order1 ,gramine4 ,bast fibres of fibro-vascular bundles4 ,length1 #ae mm42 diameter1 #jjab mm42 ratio1 #abe4 ,illustrated in ,figs4 #aj1 #aa4 ,in ,fig4 #aj1 the fibro-vascular #ef bundles f are seen spread throughout the interior of the leaf1 but the intervals1 instead of being occupied by parenchyma1 with large cells and thin walls1 are filled with a compact mass of fine solid fibres f2 e1 external epidermis2 e1 internal epidermis2 mag4 #ajj4 ,in ,fig4 #aa1 a is a section of a group of fibres2 b1 fibres seen longitudinally2 c1 ends2 mag4 #cjj4 ,illustration3 ,,fig4 #aa4 ,microscopic features4--,short1 smooth1 cylindrical1 uniform in diameter1 central canal very small1 extremities rounded1 truncated and bifurcated4 ,section4--,minute1 generally oval1 sometimes polygonal2 central cavity represented by a point4 ,micro-chemical reaction4--,both blue and yellow with iodine solution4 ,in examining a paper containing esparto under the microscope1 the pulp will be found to contain1 in addition to the fibres of the fibro-vascular bundles1 a certain number of the cuticular cells 7see ,fig4 #ab71 together with some of the fine hairs which are seen in the section 7,fig4 #aj74 ,these are very characteristic4 ,general chemical characteristics4--,pecto-cellulose mixed with some ligno-cellulose4 #eg ,composition 7,hugo ,mller73-- ,spanish4 ,african4 ,cellulose #dhbe #dehj ,fat and wax #bjg #bfb ,aqueous extract #ajai #iha ,pectous substances1 c4 #bfci #bicj ,water #ich #hhj ,ash #cgb #cfg ,,straw4--,order1 ,gramine4 ,microscopic features4--,generally similar to those of esparto4 ,there are1 however1 differences of shape and dimensions of the serrated cuticular cells1 which differentiate the various kinds of straw from each other and from esparto4 ,illustration3 ,,fig4 #ab4 ,in ,fig4 #ab are shown these cells1 from maize-straw 7a and b72 from rye-straw 7c7 and from esparto 7d74 ,the #eh following table gives the dimensions of the cells from different kinds of straw3-- ,length4 ,breadth4 ,barley #jajc-jbbd mm4 #jjab-jjad mm4 ,rye #jjhf-jcde #jjab-jjaf ,wheat #jaeb-jddi #jjah-jjbd ,oats #jahf-jddh #jjab-jjag ,another distinctive feature of straw-fibre is the presence in it of a number of oval cells1 derived from the pithy matter attached to the inside of the stem4 ,these are clearly shown at b 7,fig4 #ac71 which represents the general appearance of straw pulp4 ,illustration3 ,,fig4 #ac4 ,general chemical characteristics4--,both ligno-cellulose and pecto-cellulose4 ,the following are the results of analyses of straws 7,hugo ,mller73-- #ei ,winter ,wheat4 ,winter ,rye4 ,cellulose #dffj #dgfi ,fat and wax #adi #aic ,aqueous extract #hjg #jje ,non-cellulose or lignin #bhdi #bfge ,water #ihe #aach ,ash #eej #cbj ,,bamboo ,,and ,,sugar ,,cane4--,order1 ,gramine4 ,from the close botanical relationship of these products to the stems of the gramine of our own climate1 their microscopic features are1 as might be expected1 similar to those of straw4 ,the similarity is further shown by the chemical composition 7,hugo ,mller73-- ,air-dried ,cellulose #ejac ,fat and wax #gh ,aqueous extract #ajef ,lignin and pectous substances #bdhd ,water #hef ,ash #eac ,,new ,,zealand ,,flax4--,phormium tenax4 ,order1 ,lineace4 ,fibro-vascular bundles of the leaves4 ,microscopic characteristics4--,length of fibres1 #i mm41 diameter #jjaf mm41 ratio1 #efj4 ,fibres are fine1 regular and smooth2 the walls are uniform1 central canal small1 extremities vesicular4 ,the fibres have little cohesion in the bundle4 ,sections round or polygonal4 ,illustrated in ,fig4 #d1 p4 #ce4 ,micro-chemical reaction4--,yellow1 with iodine solution4 ,characteristic deep red colouration with concentrated nitric acid 7,mller74 ,general chemical characteristic4--,ligno-cellulose4 ,it contains #hfc per cent4 of cellulose4 ,,manilla ,,hemp4--,musa textilis1 ,abac4 ,order1 ,musace4 ,fibro-vascular bundles of leaves4 ,microscopic characteristics4--,length of fibres1 #f mm42 diameter1 #jbd mm42 ratio1 #bej4 ,fibres1 white lustrous2 the walls are uniform2 central cavity large and very apparent4 ,fibres easily detached4 #fj ,sections round or polygonal4 ,illustrated in ,fig4 #ad3 a1 section of bundle of fibres2 b1 fibres seen longitudinally2 c1 ends2 mag4 #cjj4 ,illustration3 ,,fig4 #ad4 ,micro-chemical reaction4--,yellow with iodine solution4 ,composition 7,hugo ,mller73-- ,cellulose #fdjg ,fat and wax #fb ,aqueous extract #if ,lignin and pectous substances #bafj ,water #aagc ,ash #ajb ,,wood4--,nearly1 if not the whole of the chemical wood pulp used in this country is obtained from trees belonging to the order ,conifer 7,gymnosperm71 more particularly from the genera ,abies and ,pinus4 ,in ,america1 however1 poplar and other woods are largely employed4 ,the conifer yield a larger proportion of pulp than most other woods1 the individual fibres1 moreover1 are longer1 and for these reasons it is generally preferred4 ,on the other hand1 however1 poplar is more readily acted upon by reagents4 ,fig4 #ae gives the microscopic appearance of #fa the fibre of the common white fir4 ,it is characterised by the presence of numerous pitted vessels 7,fig4 a74 ,illustration3 ,,fig4 #ae4 ,pine wood consists essentially of a compound cellulose1 resembling in most of its properties the jute fibre 7see p4 #af74 ,with iodine solution it gives a deep yellow colour4 ,the chemical composition of some of the more important woods will be seen from the following analyses4 7,mller47 ---------------------------------------- ----- ,birch4,beech4,lime4,pine4,poplar4 ----------------------------- ,cellulose#h #eeeb #dedgecjiefii #fbgg ,resin #aad #jda #cic #jig #acg ,aqueous extract #bfe #bda #cef #abf #bhh ,water #abdh #abegajajachg #abaj ,lignin #bhba #ciadbicbbfia #bjhh ---------------------------------------- ----- ,footnote #h3 ,for the amounts of cellulose actually obtained in practice see p4 #gg4 ,the above results are calculated on the ash-free wood4 ,the ash varies from about #jc to #jg per cent4 #fb ,,chapter ,v4 ,,processes ,,for ,,isolating ,,cellulose ,,from ,,plant ,,substances4 ,we are now in a position to discuss generally the various methods by which the paper-maker obtains cellulose from the different raw materials4 ,the special treatments necessary for each of the more important of these will be given more fully subsequently4 ,these methods1 though they vary considerably with the different materials to be treated1 may be roughly divided into two groups--the alkaline and the acid processes4 ,the former1 which we will call a1 comprises all processes in which caustic soda1 carbonate of soda and lime1 or mixtures of these are employed2 the latter1 b1 the various processes which have been introduced of late years1 involving the use of sulphurous acid1 either alone or in combination with a base1 such as lime or magnesia4 ,the processes in group a may be applied to the treatment of every known fibrous vegetable material2 those in group b are at the present time applied exclusively to the preparation of pulp from wood4 ,group a may be conveniently subdivided according to the nature of the materials operated upon4 ,it is obvious that those materials1 such as bleached cotton and linen threads and rags1 which have already undergone treatment by the textile manufacturer1 and are therefore more or less already in the state of pure cellulose1 require but little chemical treatment at the hands of the paper-maker1 whose attention is therefore chiefly directed to the removal of such adventitious matters as size1 grease1 c4 ,this can generally be effected by the employment of weak solutions of caustic soda1 or even of lime at a low pressure4 #fc ,we now have to consider the treatment of those materials which consist of the compound celluloses4 ,all methods for the isolation of cellulose from the compound celluloses depend upon a hydrolytic resolution of their constituents1 i4e4 a splitting up by combination with water into cellulose on the one hand1 and a series of soluble derivatives on the other4 ,this1 as will be shown1 may to a certain extent be accomplished by the action of water itself at a high temperature4 ,as1 however1 the products of such an action are acid bodies1 which1 if allowed to remain in contact with the cellulose1 would injuriously affect it1 and would induce the production of complicated bodies1 the removal of which from the cellulose would become increasingly difficult1 it is necessary to have present a body such as caustic soda1 which by combining with these acid bodies1 removes them as such from the sphere of action4 ,in certain raw materials1 such as straw and esparto1 we have1 in addition to the compound celluloses which form1 so to speak1 the groundwork1 a certain proportion of fatty and resinous bodies1 whose removal is brought about by the action of the caustic soda converting them into soaps4 ,the compound celluloses may be divided1 as we have seen1 into three classes--pecto-celluloses1 ligno-celluloses1 and adipo-celluloses4 ,the last-named being present in only a few paper-making materials1 and then only in very small proportion1 is without any practical interest4 ,we are concerned therefore with the two former only4 7#a7 ,pecto-celluloses4--,from what we have seen of the nature of the pecto-celluloses1 it follows that for their resolution a tolerably simple treatment with soda will be sufficient4 ,the chief members of this group in which the paper-maker is interested1 are esparto and straw4 ,the former being but very slightly lignified1 its resolution can be effected at a very low pressure2 in fact it is even possible by using tolerably strong solutions to do it by boiling in open vessels4 ,straw1 on the other hand1 though it possesses certain features in common with esparto1 is more lignified1 and in #fd consequence1 necessitates a much more energetic action to complete its resolution4 ,it is therefore usual to boil it at somewhat high pressures 7#dj-gj lb471 and with larger quantities of soda than are demanded in the case of esparto4 ,it is1 moreover1 essential1 so to regulate the treatment1 that even the most resistent portions of the straw1 such1 for example1 as the knots1 shall be completely resolved1 otherwise unbleached portions are liable to find their way into the finished paper4 ,by increasing the quantity of soda1 it is possible to boil under reduced pressure1 and vice vers2 this may be taken as a general principle applicable in all other cases4 ,we now come to the second class of celluloses1 that is to say1 the ligno-celluloses4 ,of these1 perhaps the most important are jute1 manilla1 and wood4 ,for their complete resolution1 it is imperative to employ very strong solutions at very high temperatures and pressures2 thus in the case of wood it is necessary to boil at temperatures corresponding to a pressure of #ajj-abj lb4 per square inch4 ,the use of strong caustic soda solutions at high temperatures is attended with very serious objections1 apart from the question of cost4 ,among these may be mentioned the destructive action of the soda upon the cellulose itself1 involving a considerable loss of pulp2 the de-hydration1 condensation1 and oxidation of the non-cellulose portion of the fibre 7which1 as we have seen 7p4 #be7 is of the nature of an aldehyde1 and therefore peculiarly susceptible of such changes71 and the formation of dark coloured products which remain intimately combined with the residual cellulose2 the inconvenience of working at very high temperatures and pressures4 ,with a view to removing the difficulties attending the use of soda1 various processes have from time to time been proposed1 in which the hydrolytic agent is a solution of sulphurous acid in water1 either alone or in combination with a base4 ,these processes are comprised under group ,b4 #fe ,several of them have lately acquired great commercial and industrial importance1 and a clear understanding of them is therefore essential to the student of paper-making4 ,though applicable to lignified fibres generally1 they have only been applied up to the present time to wood1 and it is in this connection1 therefore1 that we propose to consider them4 ,in order to bring out more clearly the fundamental differences underlying the two classes of processes1 it will be well to consider1 somewhat in detail1 these processes1 which1 although they have now a merely historical interest1 will assist the student in thoroughly grasping the rationale of the modern and improved methods4 ,water ,process4--,wood is to a certain extent resolved by treatment with water at a high temperature1 the degree of disintegration being1 within certain limits1 proportional to the temperature at which it is digested4 ,the volatile products of the resolution are chiefly acids of the acetic series1 furfurol and terpenes4 ,the non-volatile soluble products are for the most part acids4 ,this process was studied by ,fry1 who1 in #ahff1 made it the subject of a patent4 ,he found that under the most favourable conditions of treatment1 the yield of brown pulp amounted to #gj per cent4 of the wood employed4 ,the objections to the process were sufficiently obvious3 the pulp produced was of low quality1 and the soluble products acted powerfully on the iron digesters employed4 ,the chemical causes of its failure lie in the prominence of the conditions which determine re-combinations of the products of resolution with one another1 viz4 oxidation1 high temperature1 and the presence of acids4 ,it is worthy of note that in one experiment the amount of acids produced from #ajj parts wood were equivalent to #cd parts of soda 7,na#b,o74 ,this was by far the most serious defect in the process1 and it eventually caused its abandonment in favour of the older method of treatment with caustic alkali4#i ,footnote #i3 ,see ,journ4 ,soc4 of ,arts41 ,february #ahhc1 p4 #bbc4 ,alkali ,processes4--,the first to develop the alkali process #ff were ,watt and ,burgess1 in ,america 7#ahec-aheg71 and ,houghton in this country4 ,to follow up the several modifications introduced is unnecessary2 they differ from one another in the economical balance which they strike between temperature and quantity of chemicals3 thus ,watt and ,burgess employed a lye of #ab ,baum1 and digested at #fj lb4 pressure 7equal to #aeb ,c471 whereas ,houghton used a lye of #d ,b41 at #ajj-ahj lb4 ,one great defect of these processes was the gradual neutralisation of the alkali1 necessitating as a compensating condition the employment of a very high temperature towards the end of the operation4 ,to overcome this objection1 ,ungerer devised a process which aimed at securing a properly graduated action of the lye4 ,this process1 being based on an eminently rational view of the action of the alkali1 is worthy of a more extended notice1 especially as the principle on which it is founded is capable of wide application4 ,a system of nine vertical digesters1 connected together in series by means of pipes and cocks1 so that the liquid contents can be transferred from one to the other in succession1 is the main feature of the method employed4 ,in connection with this system there is a double service of pipes1 by which the hot soda lye at #ij lb4 pressure1 and cold water1 may be respectively introduced4 ,the operation is so conducted that in five of the digesters wood is being treated at a high temperature1 in three the pulp is being washed1 while the remaining one is being charged with fresh wood4 ,the whole round of operations may be described thus1 numbering the digesters according to their position in the series3--,nos4 #a1 #b1 and #c1 ,washing the finished pulp2 #d1 ,final treatment with lye at the extreme pressure of #ij lb42 #e1 ,digesting at lower pressure with lye previously employed in #d2 #f1 ,treatment at still lower pressure with lye which has already done duty in #d and #e2 and so on to #h1 where the liquor1 having passed through the series1 is employed at #ae-bj lb4 pressure on a fresh charge of wood4 ,the washings are conducted in such a way that the water which is introduced into #a displaces the solution in each digester without #fg the last being allowed to escape4 ,the introduction of the fresh liquor at #d is similarly accomplished1 #a1 #b1 and #c being cut off by closing the cocks which control the ingress and egress of liquid4 ,the pulp produced by this method is of a sufficiently pale colour to be capable of application for many purposes without bleaching4 ,it is converted into a perfectly white pulp by treatment in the ordinary way with from #c to #d per cent4 of bleaching powder1 calculated in the dry pulp4 ,as far as it goes the method is practically perfect1 and it appears to have given sound results1 at least as regards the main product4 ,the principal disadvantages were the complications attending such an elaborate system of working which would doubtless make it costly4 ,we have next to consider a class of processes which are based primarily upon the action of an alkali1 but which introduce the simultaneous action of a soluble sulphide1 generally that of sodium4 ,as far back as #ahee ,jullion patented in this country a process of this nature1 which1 however1 does not appear to have been applied to wood4 ,the results obtained with such materials as straw and esparto appear to have been very unsatisfactory1 and to have led to the early abandonment of the method4 ,recently the increased attention which has been given to wood as a raw material has led to a revival of these sulphide processes for its treatment4 ,we believe that at least two processes of this class are being worked on the continent1 viz4 those of ,dahl and ,blitz4 ,that of the former consists in heating wood1 at pressures varying from #fj-abj lb4 per square inch1 with a solution of the following composition3-- ,sodium sulphate #cg ,sodium carbonate #h ,sodium hydrate #bd ,sodium sulphide #bh ,various compounds #c #ajj #fh ,this solution is obtained only after the process has been some time at work1 and it then remains tolerably constant4 ,the wood1 to commence with1 is boiled with a solution containing a large quantity of sodium sulphate1 with a small quantity of sodium hydrate1 obtained by boiling sodium sulphate with lime4 ,the liquor from this operation is then evaporated and calcined1 the result being a fused mass which1 when dissolved in water1 yields a liquor containing the above-mentioned ingredients4 ,the loss of chemicals is made up by the addition of fresh quantities of sodium sulphate4 ,from experiments which the authors have made with this process1 it appears1 that while it is perfectly true that pulp can be obtained1 it is necessary to employ either very strong solution or very high pressures4 ,this is equivalent to saying that either the hydrolytic action is weak1 or the tendencies to reversal of the hydrolysis are strong1 and indeed both are to be predicted from the nature of the solution4 ,one great objection to the process is that during the boiling a quantity of very foully-smelling compounds are produced4 ,the process of ,blitz consists in heating wood to from #ej-fj lb4 pressure1 with a solution of sodium sulphide1 containing an infinitesimal proportion of vanadate of ammonia4 ,it is difficult to see what influence the presence of the costly vanadate of ammonia can have on the result4 ,actual experiment on this point has failed to convince us of its efficacy4 ,although in these sulphide processes a strongly reducing agent is present1 its effect in preventing oxidation is more than outweighed by the weakening of the hydrolytic action of the soda1 both directly by its combination with sulphur1 and indirectly by the complication which it induces by combination with the soluble bye-products4 ,further1 as regards the final product1 they offer no advantage over the caustic alkali processes4 ,there is1 however1 a considerable advantage in point of economy1 which should lead to their adoption in districts where the production of malodorous gases is permitted4 #fi ,acid ,processes4--,we now come to consider the processes which are based upon the hydrolytic action of acids as a primary condition4 ,we have seen that in the water process this condition obtains as a secondary result1 and that while it aids in resolving the wood1 it also determines the limit of the action1 in consequence of its promoting secondary combination amongst the soluble products4 ,the use of powerful oxidising acids1 such as nitric and nitro-hydrochloric1 induces an action which is sufficiently drastic to cause a complete resolution of the non-cellulose constituents of the wood with the formation of soluble products4 ,the use of these acids has been made the subject of numerous patents4 ,the process of ,barre and ,blondel consisted in digesting the wood in the cold for twenty-four hours in #ej per cent4 nitric acid1 by which it was converted into a soft fibrous mass4 ,this was boiled for some hours in water1 afterwards in a solution of sodium carbonate1 and finally bleached in the ordinary way4 ,many other patents have been taken out in this direction1 but none have met with practical success1 owing doubtless1 to the high cost of nitric acid1 and the difficulty of recovery4 ,a process has lately been patented by ,young and ,pettigrew 7,no4 #ad1ihh1 #ahhd7 in which they claim the use of either nitric or nitrous acids2 the acid fumes which are evolved being condensed and reconverted into nitric acid4 ,the process has not yet1 however1 been tried on a practical scale4 ,the resolution of wood by the hydrolytic action of non-oxidising acids1 is for reasons already stated1 very imperfect4 ,an important feature1 however1 of this action is the production of glucose as a bye-product1 and a process having the double object of producing this1 together with a brown pulp1 was patented by ,bachet and ,machard in #ahfd1 and worked for some time in ,switzerland4 ,the process consisted in boiling the wood for twelve hours in dilute hydrochloric acid2 the solution1 which contained glucose to the amount of #bj per cent4 of the weight of the wood1 was drawn off1 neutralised with chalk1 and fermented by the addition of #gj yeast4 ,alcohol was separated from the fermented liquor in the usual way4 ,the residual pulp1 after being ground with stones1 was made into coarse packing paper4 ,the process failed commercially4 ,the next processes in the order of the development of our subject1 but not chronologically1 are those involving the use of reducing acids1 i4e4 those which combine with their hydrolytic function a de-oxidising or anti-oxidising action4 ,of these the only one which has been practically investigated is sulphurous acid4 ,a full account of the earlier discoveries in regard to the use of this reagent1 for the special purpose under consideration1 will be found in the ,papier ,zeitung1 #ahhd1 ,no4 #ea1 p4 #aibg2 this should be consulted by those who are interested in the history of a subject which has now grown to be of the first importance4 ,the first patented process claiming the use of sulphurous acid1 in the form of its aqueous solution1 for the purpose of disintegrating wood1 was that of ,tilghmann 7#ahff74 ,so far as is known1 however1 the results obtained by the inventor with the acid alone were such as to lead him to abandon it for solutions containing a certain proportion of base4 ,the reasons1 doubtless1 were the greater facility of preparation and simplicity of application of such solutions4 ,more recently ,professor ,pictet1 of ,geneva1 on the basis of the experience acquired by him in the preparation and employment of sulphurous acid in his patent freezing processes1 has revived and perfected a process which in other hands had proved impracticable4 ,the method and apparatus employed will be found fully described in the author's specification4 ,the process consists in digesting the wood in closed vessels with an aqueous solution of the acid 7#aj-ab per cent4 ,,so#b7 at #agf-aid ,f4 7#hj-ij ,c471 and under the corresponding pressure 7#fj-ge lb4 per square inch74 ,a complete disintegration of pine wood is effected in about twenty-four hours' treatment4 ,the yield of pulp is1 we are informed1 from #dj-ej per cent4 of the wood 7,pinus sylvestris72 it is also stated to be readily bleached #ga with a moderate amount of bleaching powder1 and to yield a pulp of the highest quality4 ,further1 the recovery of the sulphurous acid1 for which special apparatus is provided1 is practically complete 7#ie-ih per cent474 ,in view of the probable utilisation of the bye-products1 it is interesting to observe that they are obtained in a form in which they can very readily be treated4 ,the process being as yet undeveloped on a large scale1 we cannot do more than recommend it to the consideration of paper-makers4 ,at the same time we would draw attention to the features of interest which it possesses in regard to the general aspect of our subject4 ,the resolution which it effects is obviously one of simple hydrolysis1 and it affords an indirect proof of the chemical complications which attend all other processes for disintegrating wood which employ temperature much above the boiling-point of water4 ,the soluble bye-products are obtained in the simplest form1 and may be isolated by mere evaporation4 ,as regards the chemical features of the pulp1 they will presumably be different from those of any other1 whether on the side of advantage or not it remains to decide4 ,provided the process fulfils the condition of economical working1 we have no hesitation in predicting for it a considerable development4 ,the difficulties attending the employment of a gaseous acid have doubtless operated in deterring many1 in addition to the originator1 from a complete investigation of its action1 and have led them to adopt in preference one of its several compounds with bases1 the employment of which defines a group of processes to which we now desire to call attention4 ,there is a variety of processes agreeing in the essential feature of employing a bisulphite as the disintegrating reagent1 and differing from one another only in the less essential details of method4 ,the general principle of these processes will be readily understood from what has gone before4 ,the chief agency is the hydrolytic action of sulphurous acid1 aided by the conditions of high temperature and pressure3 and the subsidiary #gb agencies are--7#a7 ,the prevention of oxidation2 7#b7 ,the removal from the sphere of action of the soluble products of resolution in combination with the sulphite as a true double compound4 ,this mode of union is well known to be peculiarly characteristic of all aldehydes1 to which class we have shown that the non-cellulose constituents of wood belong4 ,the combination is expressed by the general equation-- ,m4,,cho ,,so#c;,h,na ,m4,,ch7,,oh_/,,so#c7,na4 ,aldehyde4 ,sodium ,double compound4 bi-sulphite4 7#c7 ,the removal of a portion of the constituents in combination with the base1 i4e4 with expulsion of sulphurous acid4 ,the verification of these views has been afforded in the course of an investigation of the bye-products from the ,ekman process1 undertaken by the authors for ,messrs4 ,thomson1 ,bonar ,co41 the proprietors of the patent4 ,as the various bisulphite processes differ chiefly in their working details1 the essential feature of the employment of a solution of sulphurous acid1 combined with a certain amount of base1 being common to them all1 it will not be necessary to do more than examine one or two typical cases4 ,we shall select those of ,ekman and ,partington1 the latter being based upon ,francke's patent1 with certain modifications and additions4 7#a7 ,the ,chemicals employed4--,in both cases sulphur is used as the source of the sulphurous acid4 ,the ,ekman process starts from magnesite1 a native carbonate of magnesia4 ,this is converted by calcination into magnesia1 and in this state is introduced into lead-lined towers1 through which is passed sulphurous acid gas1 obtained by burning sulphur in suitable furnaces1 while a stream of water trickles down from the top4 ,the supply of the gas being properly adjusted1 a continuous production of a solution of magnesium bisulphite of uniform strength is obtained4 ,to secure this uniformity1 constant attention is necessary1 and further1 the loss of sulphurous acid by oxidation to sulphuric acid1 and by diffusion1 is1 in consequence of its distribution over so large a surface1 #gc and with free exposure to the air1 necessarily very large4 ,it is unnecessary1 however1 to point out that the preparation of the magnesium bisulphite is capable of very considerable modification2 in fact1 we understand that numerous improvements in this direction have already been introduced by the proprietors of the process4 ,partington's method1 in addition to the advantage of starting from lime1 the cheapest of all basic substances1 is free from the disadvantages referred to as attending the use of a tower4 ,it consists in passing the sulphurous acid gas through a series of three vessels connected together with pipes4 ,into these vessels a charge of milk of lime is introduced1 and the two first being closed air-tight1 the gas is passed in4 ,the third remains open to the air1 and from it escapes a continuous stream of nitrogen1 resulting from the removal of the oxygen by the burning sulphur1 from the stream of air which is blown through the sulphur retort at a pressure of #e lb4 to the square inch4 ,the expenditure for chemicals is under #al4 per ton1 whereas1 by the ,ekman process1 it has been variously estimated at from #bl4 to #cl4 #ajs4 per ton4 ,provided therefore1 that as good pulp can be obtained by ,partington as by ,ekman1 the former offers considerable advantages both from point of view of simplicity and economy4 ,doubtless the cost of chemicals could be somewhat reduced in both systems by the adoption of a cheaper form of sulphur1 such as pyrites4 ,preparation of the ,wood4--,although the acid sulphite processes can1 by suitable modifications1 be made available for the preparation of cellulose from almost all kinds of wood1 yet it is necessary1 in order to insure uniformity of result1 not only to take care that the wood is carefully selected1 but that it is freed from bark and roots1 which1 if allowed to remain1 would be imperfectly pulped1 and would be exceedingly difficult to bleach4 ,the most suitable kind of wood is ,pinus sylvestris4 ,after the bark has been carefully removed the logs are sawn into boards of ordinary sizes4 ,this treatment #gd exposes the knots1 which are then removed either by boring or cutting out with an axe4 ,the pieces are then passed through a machine1 which cuts them or rather breaks them into fragments about an inch long4 ,in order that the acid sulphite may as quickly as possible enter into the wood1 these fragments must be crushed and opened out by passing through heavy rollers3 moreover1 the wood is cut across the grain1 by which means it is more or less split up into lamin4 ,a machine for this purpose has been patented by ,fry1 ,ransome1 and ,wilkie 7,no4 #aa1chi1 #ahhd74 ,the ,boiling ,process4--,ekman uses a lead-lined1 jacketed cylindrical boiler1 suspended on trunnions1 so that it can be turned upside down for discharging4 ,the pressure in the outer jacket is #gj lb4 per square inch1 while inside the boiler it is #ij lb41 the difference being due to the tension of the sulphurous acid gas4 ,the duration of boiling is from ten to twelve hours4 ,partington1 on the other hand1 boils with live steam1 and therefore is enabled to use a boiler of simpler construction4 ,his boilers are spherical1 lead-lined and rotary4 ,the pressure employed does not exceed #fj lb4 per square inch1 the time of boiling being about sixteen hours4 ,various other sulphite processes have been from time to time devised1 which differ but little either in principle or in working detail from those described1 and therefore a brief mention of them will suffice4 ,mitscherlich employs a bisulphite of lime in somewhat weaker solution than that employed by ,francke or ,partington1 and in order to produce the same result he is obliged to extend the time of boiling to from #dj to #fj hours4 ,graham1 after treating the wood with a mono-sulphite1 injects into the boiler either a solution of a bisulphite or gaseous or liquid sulphurous acid4 ,flodgvist uses a solution prepared by dissolving bones in sulphurous acid solution4 ,the cellulosic products of the various processes present certain slight differences1 but so far as has been investigated1 not such as to constitute a distinct advantage for one or #ge another4 ,one feature of these processes1 to which but little attention has hitherto been paid1 is that of the utilisation of their bye-products4 ,these bodies are1 as already indicated1 obtained in a condition not materially different from that of the parent substance1 the non-cellulose constituents of the wood4 ,one important property of these bodies1 and one capable of considerable application1 has been made the basis of a patent by the authors4 ,when a solution of gelatin is added to the liquors in which wood has been treated by any of the bisulphite or sulphurous acid processes1 a body is precipitated in the form of a caoutchouc-like mass which can be dissolved in neutral sodium sulphite solution1 or in weakly alkaline solutions1 and can be reprecipitated on addition of alum to the solution4 ,the substance consists of a compound of the gelatin with the non-cellulose constituents resembling1 but not identical with1 as has been supposed1 the precipitate obtained by adding tannic acid to a solution of gelatin4 ,the solution of this substance in sodium sulphite can be applied to many of the purposes to which gelatin itself is ordinarily applied4 ,a serious objection to all processes involving the use of sulphurous acid or acid sulphite1 and one which has to some extent deterred paper-makers from adopting them1 is the necessity of using a boiler lined with lead4 ,in addition to the fact that such boilers are heavy and costly1 they are objectionable on account of the difficulty and expense of keeping them in thorough repair4 ,this difficulty arises from the fact that1 owing to the different co-efficients of expansion of lead and iron1 the lead lining originally placed in contact with the iron or steel shell of the boiler1 becoming detached on heating1 swells out in various places1 which are thus rendered weaker and liable to fracture4 ,this is especially the case if1 in the course of lining the boiler1 any air has been allowed to remain between the two linings4 ,various expedients have been proposed to obviate these defects but with only partial success4 ,graham 7,eng4 ,pat4 ,no4 #ecfg1 #ahhc7 coats the plate of his boiler by pouring molten lead upon the perfectly clean surface which has been #gf previously prepared with zinc chloride4 ,sometimes minute holes are drilled in the iron plate to allow the escape of air4 ,notwithstanding all the attempts that have been made1 the use of a lead-lined boiler is a serious objection1 and any process which will fulfil the conditions on which the bi-sulphite processes depend1 and which at the same time admits of the use of the ordinary iron boilers1 is an obvious desideratum4 ,such a process is that patented by one of the authors 7,cross1 ,no4 #dihd1 #ahhj71 claiming the use of solutions of the neutral sulphites with or without the further addition of an alkali4 ,this process is very suitable for the treatment of fibres such as straw1 jute1 c41 but not economically applicable to the preparation of wood pulp on account of the cost of chemicals4 ,the preservative effect of the sulphite is shown by the largely increased yield of pulp4 ,the chief advantages of the various bi-sulphite processes for the preparation of wood pulp over the old soda processes are1 7#a7 the increased yield of fibre2 7#b7 the preservation of its original strength1 and 7#c71 the economy in chemicals4 ,it is well known that cellulose1 even in its most stable forms1 is attacked more or less by hot solutions of the caustic alkalis1 and is more or less profoundly modified according to the strength of the solution and the temperature at which it is employed2 while on the other hand the solutions of the bisulphites affect it but little4 ,thus1 the authors have exposed jute cellulose1 which is of the same nature as that obtained from wood1 to the action of magnesium bisulphite under the conditions which obtain in the ,ekman process1 without its undergoing sensible loss of weight1 and further1 they have determined the amount of cellulose in freshly cut grasses1 in which it is but imperfectly elaborated1 and therefore very susceptible of modification1 both before and after treatment by the process1 and in each case the percentage obtained was the same4 ,there is therefore no doubt that in the bisulphite processes1 even the structurally delicate forms of cellulose are conserved4 ,as before indicated1 the influence of this upon the yield of cellulose is of course very marked2 the yield from white pine1 #gg by the soda process1 being approximately #cc per cent41 whereas by the ,ekman process it is from #de-ej per cent4 ,it is important to remember that this increased yield of cellulose cannot fail to affect the quality1 and therefore the paper-making properties of the pulp4 ,papers made entirely by the bisulphite processes have a strongly marked individuality1 being distinguished by their hardness and transparency4 ,in regard to the bleaching of the pulp1 it will be found that some practical experience is required for the control of the operation1 so as to produce uniform results4 ,although the pulp produced by these processes is of a very light-grey colour1 so light indeed that they may be used for certain low classes of white paper without further treatment1 yet to obtain a pure white colour almost as much bleaching powder is required as in the case of soda pulps1 although the latter are much darker in colour4 ,the chief points to be observed are 7#a7 the complete removal of the sulphites from the pulp before the addition of bleaching liquor1 which would otherwise be ineffectively consumed2 7#b7 the avoidance1 in washing1 of waters containing iron1 which would combine with certain constituents of the pulp to form dark-coloured bodies4 ,the following ,table1 compiled from ,dr4 ,hugo ,mller's #8,pflanzenfaser1' is of interest1 as indicating the probable yield of pulp from different woods1 compared with the amounts obtained in actual practice by the ,watt and ,burgess 7soda7 process3-- ---------------------------------------- ----------------------------- ,water ,lignin1 ,pulp--,watt ,water4 ,extract4 ,resin4 c4 ,cellulose4 and ,burgess ,process4 ---------------------------------------- ------------------- ,birch #abdh #bfe #aad #bhba #eeeb #djjj ,pine #abhg #dje #afc #bhah #ecbg #cdgj ,oak #acab #abbj #jia #cdcj #cidg #bjfj ,chestnut #abjc #eda #aaj #bhhb #ebfd #beaj ---------------------------------------- ----------------------------- ,the following ,table1 which gives a concise account of the various typical processes that have been employed for the preparation of wood pulp1 will be readily understood in connection with the theoretical considerations previously discussed3-- #gh ,,view ,,of ,,the ,,chemical ,,processes ,,for ,,disintegrating ,,wood4 ,aqueous ,alkalis4 ,water4 ,aqueous ,acids4 ,hydrolysis1 aided by alkali ,hydrolysis1 aided by acids 7a7 ,oxidising and hydrolytic-- directly1 also indirectly by formed from the wood4 7,fry1 combination with products of #ahfg7 ,nitric acid4 7,coupier and resolution4 7,watt and ,burgess1 ,mellier1 #aheb4 ,barre and #ahec4 ,houghton1 #aheg47 ,limit of action determined by ,blondel1 #ahfa47 reversal of hydrolysis1 i4e4 dehydration aided by oxidation4 ,nitro-hydrochloric4 7,orioli1 #ahfe47 7b7 ,simply hydrolytic-- ,hydrochloric acid4 7,bachet and ,machard1 #ahfd47 7c7 ,reducing and hydrolytic-- ,sulphurous acid4 7,tilghmann1 #ahff4 ,pictet1 #ahhb47 ,solutions of ,alkaline ,bisulphites4 ,sulphides4 ,hydrolysis1 aided primarily ,hydrolysis1 aided by alkaline by sulphurous acid1 and bases directly and indirectly secondarily by combination of by combination with products4 products with bisulphites1 also by prevention of oxidation4 ,reversal of hydrolysis lessened ,water1 together with neutral 7,tilghmann1 #ahff4 ,mitscherlich1 by presence of reducing agent4 ,sulphites4 #ahgd4 ,ekman1 #ahha4 ,francke1 #ahha4 ,graham1 #ahhb47 7,both categories3 ,jullion1 ,simple hydrolysis-- #ahee4 ,blitz1 #ahhc4 ,dahl1 #ahhd47 ,products removed from sphere of action by combination with base and sulphite4 7,cross1 #ahhj47 ,oxidation prevented by presence of sulphite4 #gi ,,chapter ,,vi4 ,,special ,,treatment ,,of ,,various ,,fibres2 ,,boilers1 ,,boiling ,,processes1 ,,etc4 ,we have already1 in ,chapter ,v41 discussed in a general way the principles upon which the treatment of the various fibres should be based2 we now proceed to consider each fibre in detail1 giving at the same time such information as is necessary regarding the preliminary treatment of the various fibres and describing the forms of apparatus in which these operations are conducted4 ,we shall consider the fibres in the order of their simplicity of treatment4 ,rags 7,linen and ,cotton74--,the treatment necessary for rags differs largely with the quality and1 of course1 with the kind of paper for which they are intended4 ,these different qualities are known in the trade by different names and marks1 such for example as the following3--,new linen pieces1 new cotton pieces1 superfines1 dark fines1 grey linen1 sailcloth1 seconds1 thirds1 c41 c4 ,the two former consist of the cuttings produced in the manufacture of various garments1 c42 not having been worn1 they are usually free from dirt1 and are1 in fact1 if bleached1 nearly pure cellulose1 containing only the starch and other sizing material which has been added in the process of finishing the goods4 ,they may1 of course1 contain considerable quantities of china clay or other loading material4 ,in purchasing rags1 therefore1 regard should be had to the probable presence of these bodies4 ,such rags require only a very slight treatment2 in fact1 for certain classes of paper they might be used without any preparation4 ,if1 as is sometimes the case1 the rags are unbleached1 a rather more severe boiling is necessary4 #hj ,illustration3 ,,fig4 #af4 ,the greater part of the rags used in paper-making1 however1 consist of the residual portions of garments1 household linen1 c41 which vary in quality from clean1 almost unused portions1 to the very foulest sorts2 the latter require a very drastic treatment4 ,the first thing to be done with the rags is to 8sort0 and cut them into convenient pieces4 ,this is usually done by women1 who stand at tables furnished with broad knives firmly fixed into them1 with the backs towards the worker1 and inclined at a slight angle4 ,near to the women are placed a number of boxes1 corresponding with the number of qualities of rags1 lined at the bottom with coarse wire gauze1 into which the different sorts are put4 ,the distinctions made are purely arbitrary1 but as a general rule the rags are sorted with special reference to their colour and the material of which they are composed4 ,the coloured rags may be allowed to accumulate1 and then made into a coloured paper4 ,during the process of cutting1 all hard substances1 #ha such as buttons1 pieces of iron1 c41 are carefully removed4 ,the rags are cut into pieces of from two to five inches square4 ,in some mills machines are used for cutting4 ,fig4 #af shows the construction of a machine that may be used either for rags or rope4 ,the material is passed into the machine along the table ,a1 where it passes between the stationary knife ,c and the knives ,b1 fixed in the revolving drum ,d4 ,the cut rags fall into a receptacle placed underneath the drum4 ,notwithstanding the extra expense of cutting by hand1 it is nevertheless preferred by many1 especially for the finer grades of paper4 ,one reason for this is to be found in the fact that more perfect sorting and removal of impurities can be effected4 ,it is moreover said that less waste of fibre occurs in the subsequent operations4 ,illustration3 ,,fig4 #ag4 ,the next process which the rags undergo is that of removing all loose extraneous matter4 ,this may be done in a machine such as is shown in ,fig4 #ag4 ,the rags are fed continuously by the endless travelling platform ,a into the willow4 ,this consists of two wrought-iron drums1 ,b ,b1 furnished with wrought-iron teeth ,c1 which when the drums revolve pass rapidly near to the stationary teeth fixed into the cast-iron framework of the willow4 ,the sides are covered in with cast-iron doors1 and the top is covered over #hb with sheet iron4 ,underneath the drums is a grating for the escape of dust4 ,the rags1 having been thoroughly beaten by the teeth of the drums1 pass into the duster ,d1 consisting of a kind of hollow cylinder ,e1 made of strong iron bars securely fastened to the circular ends ,f1 the bars being covered with wire cloth or perforated zinc4 ,it is made to revolve almost horizontally1 a slight dip being given to it in order that the rags may be carried forward to the lower end4 ,the bars or skeleton of the cylinder are furnished with a number of teeth securely bolted on4 ,the whole is enclosed in a strong wooden box in which it revolves1 and which serves to collect the dust passing through the wire cloth4 ,the cylinder ,e is driven by the gearing ,g4 ,this combined willow and duster may be used for dusting and cleaning not only rags1 but almost any other kind of fibre4 ,the willow and duster sometimes form two separate machines4 ,the cleaned and dusted rags are now ready to be boiled1 although it is the practice in some mills to give them a preliminary washing with water4 ,the boiling may be conducted either in spherical or cylindrical boilers1 or in the ordinary vomiting boilers described under ,esparto4 7,see p4 #ib47 ,in ,fig4 #ah is shown1 part in section and part in elevation1 a spherical rag-boiler1 as manufactured by ,messrs4 ,g4 ,w4 ,bertram4 ,this boiler1 of from #h to #i feet diameter1 is supported by means of the hollow journals ,a on the standards ,b1 and is made to revolve by means of the gearing ,c4 ,steam enters by the pipe ,d1 which is fitted with a safety-valve ,e1 and vacuum valve ,f4 ,the steam on entering the boiler is distributed by means of the 8baffle-plate0 ,g4 ,lye enters by the pipe ,h4 ,the boiler is fitted with two doors ,i1 wherewith to fill and empty2 the waste lye is run off by the cock ,j4 ,l is a small blow-through cock4 ,the false bottom ,k prevents the rags from choking up the cock and also serves to drain off the waste liquor4 ,illustration3 ,,fig4 #ah4 ,the alkali employed may be either caustic lime1 caustic #hc soda1 sodium carbonate1 or a mixture of the latter and lime1 which is of course equivalent to using caustic soda4 ,the proportion of alkali depends upon so many considerations that it is quite impossible to give exact information on this point4 ,in the case of caustic soda1 a quantity equal to from #e-aj per cent4 on the rags may be taken to be a fair average4 ,if lime be used it should be slaked with water1 made into a thin milk and carefully filtered through fine wire cloth to keep back the particles of sand1 coal1 c41 which lime is always liable to contain4 ,from #e-aj per cent4 may be used4 ,the amount of lime actually dissolved in the water is relatively small 7#ac grms4 per litre72 the portion in solution however1 rapidly combines with the grease1 dirt1 and colouring matter of the rags and forms with them insoluble compounds1 a fresh portion of lime being at the same time dissolved4 ,this formation of insoluble compounds constitutes an important objection to the use of lime1 as they are liable #hd to remain to some extent fixed in the rags and are with great difficulty removed by washing4 ,for this reason1 therefore1 the more soluble alkali is to be preferred4 ,moreover1 the lime sometimes tends to exert a hardening effect upon the cellulose4 ,notwithstanding these objections1 lime is used by some paper-makers in preference to soda4 ,in making choice of the chemical for boiling1 much depends on the quality of the rags and the nature of the paper for which they are intended1 so that no definite rules can be given4 ,the time of boiling varies from #b to #f hours1 according to the quality of rags1 the chemical employed1 and the pressure4 ,the use of very high pressures should be avoided as far as possible1 as there is a danger1 owing to the correspondingly high temperature1 of fixing the dirt and colouring matters instead of dissolving them4 ,the quantity of water should be kept as low as may be1 in order to have as strong a solution of alkali as possible2 this effects a saving both in the time of boiling1 and in the alkali4 ,this is of great importance where it is necessary to evaporate the whole of the waste liquors4 ,it should also be remembered that a certain amount of water is always formed by condensation in all boilers in which live steam is used4 ,on the other hand1 if too little water be added1 the rags are liable to become 8burned0 and the fibre therefore weakened4 ,during the operation the boiler should be made to revolve slowly1 in order to produce thorough circulation of the liquor4 ,the boiling being completed1 the pressure is allowed to fall1 either by cooling or by blowing off from a cock usually provided for that purpose1 and the liquor allowed to collect at the bottom of the boiler4 ,it is then run off by the cock ,j 7,fig4 #ah71 and the rags drained as much as possible4 ,water is then run in to give the rags a preliminary washing4 ,if time permits the steam may be turned in and the operation assisted4 ,after again draining1 the rags are withdrawn from the boiler into any suitable receptacle4 ,a convenient form is that of a rectangular iron box on wheels1 which can be readily transferred from one part of the mill to another4 #he ,the next process is that of washing4 ,this is usually performed in a washer or breaker1 the construction of which is shown in ,fig4 #ai4 ,illustration3 ,,fig4 #ai4 ,it consists essentially of a rectangular vessel with rounded ends1 in the centre of which1 but not extending the whole #hf way1 is a partition ,b1 known as the 8mid-feather40 ,the roll ,a1 which is furnished with a number of steel knives ,g1 and driven from the wheel ,h1 revolves in one of the compartments formed by the mid-feather4 ,in this compartment the floor is inclined in such a way as to bring the pulp well under the roll1 as shown by the dotted line ,d4 ,immediately under the roll is what is called the 8bed-plate10 the end of which is seen at ,i1 extending up to the mid-feather1 and fitted with knives similar to those in the roll ,a4 ,the arrangement of the knives1 both in the bed-plate and the roll1 is similar to that given in ,figs4 #cc and #cd4 ,the distance between the roll and the bed-plate can be varied at will by means of the handle ,e1 which is so arranged as to raise both ends of the roll simultaneously4 ,in those breakers of an older pattern1 one end only of the roll was raised1 and thus the knives became worn unequally4 ,after passing between the roll and the bed-plate1 the pulp flows down the 8back-fall0 ,d1 and finds its way round to the other side of the mid-feather4 ,on the inclined part of the floor1 and immediately in front of the bed-plate ,i1 a small depression is made1 covered with an iron grating1 for the purpose of catching buttons1 small pieces of stone1 and other heavy substances that may have found their way into the rags4 ,there is generally a similar grating with rather finer openings on the other side of the mid-feather4 ,the engine is constructed of iron1 generally made in one casting4 ,the dirty water from the rags is removed by the 8drum-washer0 ,c4 ,it is divided into compartments by the partitions shown by the dotted line c4 ,the centre of the drum is formed of a conical tube1 the narrow end of which is towards the mid-feather4 ,the ends of the drum are generally made of mahogany1 as this is found to stand the action of alkali better than any other wood4 ,the periphery is covered with fine copper or brass wire-cloth1 laid on to a backing of a much coarser material4 ,an improved form of backing has been introduced lately1 which is much more durable than wire4 ,it is formed of brass cut into the form shown in #hg ,fig4 #bj4 ,the drum can be raised or lowered by the small wheel ,f1 and it is driven by a belt on the shaft that bears the roll4 ,illustration3 ,,fig4 #bj4 ,the wash-water passes through the wire cloth into the compartments formed by the partitions c1 and finding its way down to the narrow end of the inner conical tube1 flows out through the side of the drum into a trough which is placed across the washer to receive it4 ,or it may1 as shown in the drawing1 be conducted through the mid-feather itself1 which is made hollow at this part for the purpose4 ,another form of drum-washer1 called the siphon-washer1 is sometimes used4 ,its construction will be understood by reference to ,figs4 #ba and #bb4 ,the drum is simply a hollow cylinder of wire cloth1 the ends of which are formed of wood4 ,inside the cylinder is the siphon tube ,a1 into which the water passing through the wire cloth flows4 ,the continuation of the siphon tube ,b 7,fig4 #bb7 is made of flexible tubing4 ,the action of the siphon is commenced by filling it with water through the cock ,c 7,fig4 #bb74 ,the water then flows in the direction indicated by the arrows4 ,the tube ,a is fixed1 and passes through a hollow journal fitted on to the end of the drum4 #hh ,the other end is connected with the rod ,e1 on which the driving pulley ,d is placed4 ,illustration3 ,,fig4 #ba4 ,illustration3 ,,fig4 #bb4 ,the water passing through the wire cloth on the drum carries with it a certain amount of fibre which1 unless special precautions are taken 7see 8,save-all10 p4 #aed7 is lost4 ,the amount is considerable in the case of weak rags1 and care should therefore be taken that the washing is not prolonged more than is consistent with proper cleansing1 and that the pulp should not be too much broken up at this stage4 ,the washed and broken pulp goes by the name of 8half-stuff40 #hi ,the following is the usual plan of treating rags in the washer3--,it is first half-filled with water1 and the rags from the boiler put in gradually until nearly filled4 ,water is now allowed to flow in at the opposite end to where the drum-washer is placed4 ,this1 by the action of the roll1 mixes thoroughly with the pulp and extracts all the soluble matter1 and also carries with it fine insoluble impurities4 ,the action of the knives in the roll on the rags passing between it and the knives in the bed-plate serves to break them up and thoroughly disintegrate them4 ,the dirty water then passes away through the drum-washer1 the stream of pure water being regulated so as to keep the level constant4 ,this is continued until only pure water passes away4 ,the supply is then stopped1 the washer still being kept in action4 ,as the level falls the drum is lowered by means of the handle ,f4 ,when sufficiently drained the pulp is discharged through a valve in the bottom of the engine4 ,it is now ready to be bleached4 ,this may be done in separate engines called 8potchers10 somewhat resembling the breaker or washer already described1 or it may be done in the breaker itself4 ,the process of bleaching will be described in ,chapter ,,vii4 ,occasionally1 the bleaching process is conducted in the 8beater0 itself1 but this is not to be recommended4 ,esparto4--,this fibre1 on account of its high percentage of non-cellulose constituents1 requires a large amount of soda to resolve it2 on the other hand1 being of the nature of a pecto-cellulose1 the process of disintegration may be conducted at a low pressure2 in fact1 it is the practice at some mills to boil in open vessels1 in which case1 however1 a larger amount of soda is required4 ,as has been already stated1 it may be taken as a general rule for all fibres1 that within certain limits the higher the pressure employed the less soda is required4 ,the quantity necessary also varies with the district from which the grass comes4 ,caustic soda is the chemical invariably employed2 lime1 on account of its forming insoluble compounds with the #ij non-cellulose portion of the grass1 is inapplicable4 ,not only does the amount of soda depend upon the pressure1 but it also depends to a considerable extent on the form of boiler employed4 ,the use of rotary boilers is objectionable1 as the esparto tends to collect together into compact masses1 which are with difficulty penetrated by the liquor4 ,it is therefore the almost universal practice to employ stationary boilers4 ,illustration3 ,,fig4 #bc4 ,the first treatment that the esparto undergoes is that of 8picking40 ,the bands of the bales in which esparto is packed1 generally by hydraulic pressure1 are cut1 and the grass is spread out on tables by women1 who carefully remove such impurities as weeds1 root-ends1 c41 which from their nature are with great difficulty boiled and bleached1 and which if not removed would be liable to appear in the finished paper as dark-coloured specks1 technically known as 8sheave40 ,this treatment is called 8dry-picking10 in contradistinction to a subsequent process1 known as 8wet-picking40 ,a portion of the table is covered with coarse wire gauze1 through which when the grass is spread over it loose particles of sand1 dirt1 c41 escape4 ,the cleaning of esparto can be much better accomplished by means of machinery4 ,fig4 #bc is an elevation of a machine manufactured for the purpose by ,messrs4 ,masson1 ,scott and ,bertram4 ,the grass1 which may be in the form of sheaves1 as taken from the bales1 is put in by the hopper ,a4 ,it passes thence to a conical #ia drum made of steel bars placed very close together1 driven rapidly by the shaft ,b4 ,it is provided with five rows of teeth4 ,fixed to the sides of the willow there is also a row of stationary teeth4 ,the grass is thoroughly broken up and dusted by the action of the teeth1 and is transferred to the wide end of the willow at ,c1 where it is carried forward on the travelling tables ,d4 ,during its passage along the tables it can be examined and picked by women standing on the platforms ,e4 ,the dust and dirt passing through the steel bars of the drum are drawn away by a fan through the pipe ,f4 ,this machine is also adapted so as to carry the cleaned grass to the boiler-house4 ,it is taken forward by means of travelling rakes over the tops of a series of boilers1 any one of which can be furnished by simply opening a door corresponding in position with the lid of the boiler4 ,boiling4--,the ordinary form of boiler is shown in ,fig4 #bd4 ,it is known as a vomiting boiler4 ,the grass is put in by the door ,e1 which is hinged1 and is counterbalanced by the weights ,l4 ,it is securely fastened down by the screws ,f4 ,steam enters by the inner pipe ,a1 which dips a little below the perforated false bottom ,b4 ,surrounding the steam-pipe is a wider pipe ,c1 open at the top1 which is made slightly trumpet-shaped2 also open at the bottom1 where it ends in a kind of shoulder1 on which the false bottom rests4 ,the lower part has two or more openings ,g cut away1 through which the liquor can freely pass4 ,in order to get as large a charge into the boiler as possible1 steam is turned on while furnishing1 and a quantity of caustic soda lye is also run in1 which has the effect of softening the grass and making it more compact4 ,this is continued until the boiler is well filled4 ,the action of the boiler is as follows3--,the steam passing through the pipe ,a heats the liquor that has drained from the grass through the perforations in the false bottom1 and forcing it up the wide pipe ,c1 causes it to strike against the dome or bonnet ,d1 and distribute itself again over the grass4 #ib ,this is technically known as 8vomiting40 ,in this way a constant circulation of liquor is kept up4 ,illustration3 ,,fig4 #bd4 ,the boiler is emptied by the door ,h and the liquor is run off by the cock ,i4 ,the boilers are usually supplied with a safety valve ,e1 and also with a pipe for letting off the steam when the boiling is finished4 ,the boiling generally takes from four to six hours4 ,the quantity of soda necessary depends upon the nature of the grass1 ,spanish requiring less than ,african4 #ic ,routledge1 to whom the introduction of esparto as a paper-making material is due1 gives #aj per cent4 as the proper quantity4 ,the pressures employed vary from #e lb4 to #de lb4 ,there has been a growing tendency of late to employ the higher pressures for reasons already stated4 ,illustration3 ,,fig4 #be4 ,of late years great improvements in the form of the boiler have been introduced4 ,fig4 #be is an illustration of ,roeckner's ,patent ,boiler4 ,the vomit pipe is outside the boiler4 ,steam entering by the cock ,d1 forces the liquor up the vertical vomit pipe and distributes it over the grass4 ,the pipe ,k is used for heating the liquor at the commencement of the operation by means of waste steam4 ,f ,f are gauges for indicating the height of the liquor4 ,the grass is put in by the opening ,g4 ,the pipes ,a ,b and ,c are for the supply of #id steam1 strong lye and water4 ,the boiled grass is discharged by the circular door ,e4 ,the boiler holds three tons of grass and the boiling is completed in about #b #a_/b hours1 the pressure being about #ce-dj lb4 per square inch4 ,it is claimed that by its use a saving both of time and soda is effected4 ,illustration3 ,,fig4 #bf4 ,sinclair's ,patent ,boiler is shown in ,fig4 #bf4 ,the vomit pipes1 of which there are two1 are made of thin steel plates #ie riveted to opposite sides of the boiler4 ,the liquor drains through the perforated false bottom1 and is then forced up the vomit pipes above the perforated plates through which it is distributed over the grass in a number of fine jets4 ,the boiler is charged by the door e and emptied by j4 ,the small cock a is used as a blow-through cock2 the opening b is used for blowing-off steam when emptying the boiler2 c for letting in caustic soda lye2 d for water4 ,steam enters by the small branch of the ,t pipe at the bottom of the boiler1 the other1 g being used for running off the waste liquor4 ,a boiler holds from two to three tons of grass1 and a boiling is completed in about two hours at a pressure of #dj-ej lb4 per square inch4 ,the two forms of boiler above described possess the obvious advantage of having the whole or nearly the whole of the interior available for holding grass2 the boilers can therefore be made to hold more1 and the boiling is moreover much more evenly accomplished4 ,washing4--,the boiling being completed1 the steam is allowed to escape and the liquor to collect at the bottom of the boiler where it is run away by the pipes placed at the bottom for the purpose4 ,water is then run in and steam turned on for a short time2 this is also run off1 and the grass drained as completely as possible4 ,the boiled grass is then emptied into trucks and taken away to the washing engines4 ,these resemble those already described under rags4 ,during the process of washing1 a certain amount of the shorter fibres find their way through the meshes of the wire-cloth4 ,in addition to this a large proportion of the cellular tissue surrounding the fibro-vascular bundles 7see ,fig4 #ab1 p4 #eg7 is carried away4 ,if the wash-water be examined under the microscope1 it will be seen to consist largely of this cellular matter4 ,though this entails a certain loss of cellulose1 its removal is in other respects advantageous1 as it is possessed of hardly any 8felting0 properties1 and it is moreover exceedingly difficult to bleach4 ,the amount of fibre actually obtained in practice is but little below that contained in the grass4 ,a certain loss is #if inevitable1 but this probably does not exceed #a or #b per cent4 ,the percentage of cellulose in esparto is given on p4 #eg4 ,the following numbers obtained by the authors are somewhat higher4 ,they are calculated on the absolutely dry fibre2 those mentioned are on the air-dry samples3-- ,cellulose per cent4 ,spanish #ehj ,tripoli #dfc ,arzew #ebj ,oran #dif ,there is no doubt that considerable differences occur even between different specimens of the same kind of grass4 ,it is the practice in some mills to wash the grass in a series of tanks connected together in the same way as the lixiviating tanks of an alkali works4 ,they are so arranged that pure water flows in at one end1 passes through fresh lots of grass in succession1 and issues at the further end highly charged with the soluble products of the grass4 ,by such an arrangement the grass can be washed without any loss of fibre1 and with a minimum quantity of water4 ,this latter feature is of great importance in mills where it is necessary to evaporate the whole of the waste liquors from the esparto1 as they are then obtained in a very concentrated form4 ,even with such an arrangement it is advisable to give the grass a short final treatment in the washing engine4 ,the washing having been completed1 and the esparto having been broken up into 8half-stuff10 it is now ready to be bleached 7see ,chap4 ,,vii474 ,the presse-pte system1 originally adopted for the treatment of straw1 has of late years been extensively applied to esparto4 ,the presse-pte consists of the wet end of a paper machine1 and is furnished with sand-tables and strainers4 ,the pulp is allowed to flow on to the wire cloth1 so as to form a thick web of pulp4 ,the bulk of the water passes away through the wire cloth2 a further quantity is removed by the #ig vacuum-boxes and couch-rolls4 ,the pulp1 containing from #ej to #fj per cent4 of water1 is wound round an iron rod until a sufficiently large roll is formed4 ,the advantages of the presse-pte system are the possibility of the removal of dirt and unboiled portions by means of the sand-tables and strainers1 and the very complete washing and removal of the products of the action of bleaching powder4 ,it also enables manufacturers to dispense with the somewhat costly methods of dry and wet picking4 ,the presse-pte system can also be applied to the unbleached pulp4 ,it may be interesting at this point to say something about the substances which are removed from the esparto by the caustic soda4 ,on referring to p4 #eg it will be seen that the original grass contains nearly half its weight of extractive matter1 the removal of which has to be effected4 ,only a small proportion of this is extractive matter in the ordinary sense of the term1 i4e4 that can be extracted by the usual solvents2 the remainder is intimately combined with the cellulose4 ,the action of the caustic soda is to resolve these bodies1 the cellulose remaining behind1 and the other constituents being dissolved as resinous bodies by the soda4 ,a certain proportion of the mineral constituents1 notably the silica1 dissolves in the lye1 the latter forming silicate of soda4 ,on neutralizing the liquor with an acid1 the bulk of the dissolved constituents is thrown down as a dark brown resinous mass4 ,if this crude product be purified1 it is found to consist of a definite body having the formula ,c#ba;,h#bd,o#h4 ,by the action of chlorine on this resin a bright yellow chlorine compound is formed1 resembling the compound from jute described on p4 #ah4 ,if the resin be treated with concentrated nitric acid1 a bright yellow body is formed1 which forms definite compounds with bases1 and which has the property of dyeing animal fibres a bright orange colour4 ,in addition to this body1 a yellowish-white wax can be isolated4 ,it sometimes happens that this wax is but imperfectly dissolved in the caustic lye2 if the waste liquor be allowed #ih to stand1 the wax is occasionally found to collect in small quantities on the surface4 ,various attempts have been made from time to time to remove from the waste liquors the soluble matter derived from the esparto by the addition of lime4 ,this throws it down as a very voluminous precipitate1 exceeding difficult of filtration4 ,the filtrate contains only caustic soda4 ,the difficulties of removal of the precipitate1 however1 are almost insurmountable4 ,the usual method of disposing of the liquor is to evaporate it to dryness and ignite it1 as will be subsequently described under the head of 8,soda ,recovery10 ,chapter ,,xii4 ,straw4--,straw very closely resembles esparto in its chemical constitution2 it is1 however1 more highly lignified1 and for this reason 7see p4 #fc7 requires a more drastic treatment for its resolution4 ,it is therefore usual to treat straw with rather larger quantities of caustic1 and generally at high pressures4 ,it is possible1 however1 to resolve it at #e-aj lbs4 pressure1 but the resulting pulp is more difficult to bleach1 and can only be used for inferior kinds of paper4 ,in treating straw for use in high-class paper1 it is necessary to boil under such conditions that even the knots1 which are much less readily attacked1 shall be so far disintegrated that they may be bleached with a moderate quantity of bleaching powder4 ,such a treatment1 on the other hand1 involves a diminished yield of pulp1 and at the same time a somewhat weakened fibre4 ,the kinds of straw in general use are wheat1 oat1 rye1 and barley2 the two first constituting the bulk of the raw material1 at least in this country4 ,some idea of the composition of straw may be gathered from the analyses given on p4 #ei4 ,it will be seen that the amount of cellulose is quite as high as in esparto1 but for the reasons above given and from the fact that a large proportion of the cellulose consists of cellular tissue 7see ,figs4 #ab and #ac71 which is easily attacked by soda and readily passes through the meshes of the #ii drum-washers and the wire-cloth of the presse-pte and paper machine1 the yield obtained in practice falls considerably below that from esparto4 ,in addition to the numbers already quoted on p4 #ei1 the following results of analyses made from time to time by the authors1 may be interesting4 ,the percentages are calculated on the absolutely dry material4 ,cellulose per cent4 ,oat ,straw #ebj ,oat ,straw #ece ,wheat ,straw #dif ,rye ,straw 7,foreign7 #ecj ,oat ,straw 7,foreign7 #dfe ,wheat ,straw 7,foreign7 #ejb ,the yield of pulp is greatly influenced by the conditions under which it is obtained2 high pressures and temperatures exerting considerable influence on the result4 ,this is probably the case with straw more than any other fibre1 on account of the physical and chemical nature of the cellulose4 ,it is doubtful whether much more than #ce per cent4 is actually obtained in practice4 ,straw is usually boiled in cylindrical rotary boilers4 ,some paper-makers1 however1 prefer to use one or other of the different forms of vomiting boilers already described4 ,the use of a rotary boiler is open to certain objections4 ,in the first place1 it is doubtful if they are as economical of soda as the vomiting boilers1 especially the more recent patterns2 and1 secondly1 the rotation of the boiler so disintegrates the pulp1 that a certain proportion of the cellulose1 especially those fibres which are short1 is liable to be lost during the subsequent treatment4 ,it seems probable that the best results would be obtained if the rotation of the boiler were reduced to a minimum1 in fact1 sufficient only to produce thorough circulation of the liquor4 ,the proportion of soda necessary to boil straw thoroughly is1 for reasons already stated1 greater than is the case with esparto4 ,the amount varies from #aj to #bj per cent4 on the raw material4 #ajj ,the different processes to which straw is subjected vary greatly4 ,the following may be taken as a general indication of the methods employed4 ,the straw is usually cut into short pieces of about #a-b in4 in length by means of an ordinary chaff-cutter4 ,the cut straw is carried by means of a blast of air along a wooden tube or shaft into a chamber1 the sides of which are made of coarse iron gauze4 ,this chamber is itself inclosed in another chamber1 in which the dust and dirt accompanying the straw collect4 ,the clean straw is then placed in sacks and conveyed to the boiler-house4 ,owing to the bulky nature of straw1 it is difficult to get a large charge into a boiler at one operation2 it is therefore usual1 after having filled it as completely as possible1 to run in a portion of the lye required1 and to turn on the steam for a few minutes4 ,this has the effect of so far softening the straw as to make it lie closely at the bottom of the boiler and to allow of a further quantity being put in4 ,this having been accomplished1 the remainder of the lye required is run in1 together with the requisite quantity of water1 and the steam turned on4 ,the pressure may vary from #aj to #ej1 or even #hj lbs4 per sq4 in41 and the time from #d-h hours4 ,when the boiler has sufficiently cooled1 the charge is run out by a cock in the bottom4 ,owing to the rotary action of the boiler the straw is in the state of fine pulp1 having been almost completely disintegrated2 so fine1 in fact1 that it flows readily through a #c-;in4 pipe4 ,it is run into large tanks with perforated tile bottoms1 where the excess of liquor is allowed to drain away and the pulp washed by the addition of water4 ,it is then dug out and taken to be bleached4 ,before this is done1 however1 it may be necessary to give it a further washing4 ,this may be done in the potcher itself4 ,instead of washing the straw in tanks1 it may be washed in an ordinary washing engine1 such as has been already described4 ,owing to the finely divided state of the pulp1 however1 this method1 unless the meshes of the wire-cloth covering the drum washer are very fine1 entails #aja a considerable loss of fibre4 ,it is more suitable in cases in which the straw has been boiled in stationary boilers1 and in which therefore it is less disintegrated4 ,when stationary boilers are employed1 it is not necessary to cut the straw very fine2 in fact1 it is sometimes put into the boiler whole4 ,the cutting has this advantage1 that it loosens the adhering dirt4 ,in cases where the action of the soda has not been carried far1 or when the straw has been put into the boiler whole1 the pulp will not be disintegrated to the same extent1 and it would not flow through a narrow pipe4 ,it is necessary therefore to discharge the boiler through the doors used for filling4 ,a novel form of washer especially adapted for straw1 whereby the washing is effected with the minimum quantity of water1 has been used on the ,continent to a considerable extent1 and to some extent in this country4 ,the pulp is caused to pass along a series of revolving cones covered with wire-cloth1 through which the liquor escapes4 ,as it reaches the end of each cone1 the pulp is emptied into a small tank containing water from the cones further on in the series4 ,it is carried forward by means of hollow bent arms connected with the inside of the next cone1 which then discharges it at the other end1 to be again carried forward4 ,as already stated1 the presse-pte system is largely adopted for straw pulp2 it has been described under ,esparto4 ,it may sometimes be employed with advantage before bleaching1 though it is generally used after4 ,a method of treating straw is sometimes adopted which produces a pulp of higher quality than is obtainable by the ordinary method4 ,the washed pulp is mixed in a chest provided with stirrers1 with a large quantity of water1 and is then pumped into another chest placed at a higher level1 from which it flows between a pair of hard granite millstones1 the surfaces of which are cut into radial grooves4 ,the stones are fixed horizontally1 and are made to revolve at a very rapid rate4 ,during the passage of the pulp through the stones1 the knots1 weeds1 and other hard portions of the #ajb straw which may have resisted the action of the alkali are reduced to a fine state of division1 and are thus more readily acted upon in the subsequent operation of bleaching4 ,the degree of fineness to which the pulp is reduced can be determined by regulating its flow and the distance between the stones4 ,pulp produced in this way is of a very even character1 and is comparatively free from unbleached particles4 ,within the last few years a process of treating straw has been introduced which1 on account of the high quality of the pulp produced1 has attracted considerable attention from paper-makers4 ,it consists in exposing pulp obtained in the usual way by the action of caustic soda to the action of chlorine gas4 ,the method was patented in ,england on ,march #crd1 #ahhj 7,no4 #ich71 by ,friedrich ,carl ,glaser4 ,the amount of soda in the preliminary boiling is reduced much below that necessary for perfect pulping1 the result being that the cellulose is much less liable to be destroyed1 and thus a greater yield is obtained4 ,the pulp is thoroughly washed and partially freed from moisture in a centrifugal machine until only about #gj per cent4 remains4 ,the partially dried pulp is then exposed in leaden or stone chambers for some hours in an atmosphere of chlorine1 produced by the action of hydrochloric acid upon manganese dioxide4 ,by the action of the chlorine1 those portions of the straw which have been but imperfectly acted upon by the caustic soda in the boiling process are completely disintegrated1 or1 rather1 are rendered more susceptible to the action of the bleaching liquor employed subsequently4 ,the consequence is that when bleaching liquor is added1 the whole of the straw is rapidly reduced to the state of pure cellulose1 and the finished product is remarkably free from anything like unbleached portions4 ,owing to the fact that the action of the caustic is minimised1 a considerable proportion of the more easily degraded cellulose survives1 and the yield of pulp is thereby increased4 ,the process is1 however1 necessarily expensive4 ,the action of the chlorine will be readily understood by a reference to p4 #ai4 #ajc ,owing to the fact that a considerable proportion of the pulp obtained from straw consists of cellular tissue 7see ,fig4 #ac1 p4 #eh71 which1 although cellulose1 is devoid of fibrous structure1 paper made from straw only is found to be much weaker than that made from fibres such as esparto4 ,on the other hand1 being a cheap material1 and one capable of yielding a very white pulp with a moderate quantity of bleach1 it is held in considerable repute by many paper-makers1 especially as a material for mixing with esparto4 ,it is sometimes mixed with cotton and linen rags1 even in the finest qualities of paper4 ,jute1 ,manilla1 ,adansonia1 c4--,the boiling processes already described under ,esparto and ,straw are1 with certain slight modifications1 equally applicable to fibres of this class4 ,for convenience in manipulation they are usually cut into small pieces by a machine such as is shown in ,fig4 #af1 and are then cleaned and dusted in a willowing machine4 ,the boiling process calls for no special notice beyond what has been already said with regard to other fibres4 ,a cheaper method1 and one which is largely adopted in mills where only a coarse dark-coloured paper is required1 consists in boiling the jute or other fibre in lime4 ,such a treatment is1 however1 not so effective as one in which caustic soda is used1 and the fibre produced is harder and coarser in every way4 ,the yield of pulp1 however1 owing to the fact that the fibre is imperfectly resolved1 is greater4 ,in many cases1 from questions of economy1 lime may be advantageously employed4 ,jute can only be employed successfully when it is imperfectly resolved1 that is to say1 when it is not reduced to the state of pure cellulose4 ,in such a state it forms a comparatively weak fibre1 owing to the fact that it is resolved into its individual fibres4 ,if the filaments are not completely resolved1 then a strong fibre is the result1 but in this case1 the pulp cannot be obtained in a pure white state4 ,owing to this fact1 jute has had up to the present only a limited consumption1 except for the manufacture of coarse papers4 #ajd ,jute and ,adansonia are largely used for papers where strength is of more importance than appearance1 such1 for example1 as paper for telegram forms1 strong wrapping paper1 c4 ,wood4--,the processes for treating wood have already been described in ,chapter ,v4 ,when an alkaline treatment is adopted1 the alkali employed is1 at least in this country1 caustic soda4 ,in ,germany the sulphide of sodium processes have been very largely adopted4 ,the alkali method is1 however1 being superseded by the more perfect and more economical method of treatment with sulphurous acid or acid sulphites4 8,broke0 ,paper4--,under this head may be included all the partially formed paper which is always obtained in greater or less degree when a paper-machine is started1 or such portions as are occasionally unavoidably damaged in its passage over the drying cylinders1 together with the imperfect or rejected portions4 ,it may also include used or waste paper1 a large proportion of which1 if not too dirty1 is re-made into paper4 ,the cleaner portions1 especially if they have not been dried1 are frequently returned direct to the beaters1 and mixed with other pulp4 ,that which has been actually made into paper requires to be softened by boiling in water and #aje gentle breaking in an engine4 ,it may be necessary to heat it for a short time in a weak solution of caustic soda4 ,this may be done either in a breaker or in special tanks provided for the purpose4 ,paper which has been printed upon requires a rather more drastic treatment1 and it must of course be used for an inferior quality of paper1 as it is impossible to get it to as good a colour as the original pulp from which it was made--at least not economically4 8,broke0 paper may be advantageously disintegrated by means of an edge-runner4 ,it consists of a pair of stones arranged in the same way as an ordinary mortar-mill 7,fig4 #bg74 ,illustration3 ,,fig4 #bg4 ,mechanical ,wood ,pulp4--,a very large quantity of pulp is used in the commoner kinds of paper1 such as cheap news1 c41 which is obtained by disintegrating wood by mechanical means alone1 no chemicals being employed4 ,the idea of making paper in this way dates back about #ajj years1 but owing to the want of suitable machinery it is only lately that a good product has been obtained4 ,the following are1 in a general way1 the details of the process employed3-- ,the wood is first cut up into blocks1 the size of which is determined by the width of the stones used for grinding2 any knots present are cut out with an axe4 ,the stones are made of sandstone1 and are covered over three quadrants with an iron casing1 the remaining quadrant being exposed4 ,the surfaces of the stones are made rough by the pressure of a steel roll studded with points1 and which is pressed against it while revolving4 ,in addition to this1 channels about #a_/d in4 deep are cut into the stone at distances of #b-c in4 ,they are made in two sets1 crossing each other in the centre of the stone1 and serve to carry off the pulp to the sides of the stone1 in addition to giving increased grinding-surface4 ,the pressure of the blocks of wood against the stones is steadily maintained by screws worked by suitable gearing2 this is necessary in order to obtain a pulp of uniform character4 ,a stream of water is kept constantly playing on the stone2 by this means1 the pulp as fast as it is formed can be conveniently carried away4 ,it is first passed #ajf through a rake1 which retains small pieces of wood that have escaped grinding4 ,the stream of pulp then passes through the sorters1 the object of which is to keep back such portions of the wood as have not been sufficiently disintegrated4 ,these consist of cylinders about #c ft4 long and #b ft4 in diameter1 covered with a coarse wire-cloth4 ,the fibres that are retained by this wire fall into the refiners1 which consist of a couple of horizontal cylinders of sandstone1 the upper one only of which revolves4 ,here they are further #ajg disintegrated1 and are again passed through the wire-cloth2 this is repeated until all the fibres have passed through4 ,the pulp1 after passing through the first sorter1 may be conducted through a series of gradually increasing fineness1 and1 by this means1 be separated into different qualities4 ,though pulp so prepared cannot compete with chemically-prepared stuff1 as the fibres are extremely short1 and have comparatively little felting-power1 it may be used with advantage as a sort of filling-material4 ,illustration3 ,,fig4 #bh4 ,various modifications of the foregoing process have from time to time been proposed2 among others1 that of softening the wood by previous soaking in water1 or steaming1 seems to be valuable1 as by so doing1 it is highly probable that a longer fibre could be obtained1 the soft wood being more readily torn away by the stones4 ,some inventors have proposed to replace the sandstone by an artificial stone containing a large quantity of emery4 ,an improved method of preparing mechanical wood pulp1 lately patented by ,mr4 ,a4 ,l4 ,thune1 of ,christiania1 has been communicated to us by ,mr4 ,carl ,christensen4 ,illustration3 ,,fig4 #bi4 ,illustration3 ,,fig4 #cj4 ,the apparatus employed is shown in ,figs4 #bh1 #bi1 and #cj4 ,fig4 #bh illustrates an arrangement of grinding apparatus fixed direct on to a turbine4 ,the stone is fastened on to the shaft ,s worked by the turbine ,t4 ,the wood in the form of small blocks is kept in contact with the stone by a number of hydraulic presses ,p4 #ajh ,a somewhat similar arrangement1 but placed horizontally1 is shown in front and side elevation in ,figs4 #bi and #cj4 ,the same letters correspond4 ,illustration3 ,,fig4 #ca4 ,the ground and sorted pulp is made into thick sheets by means of the board machine shown in ,fig4 #ca4 ,the pulp mixed with water passes down the shoot ,d into the vat ,b in which the cylinder ,k revolves4 ,this cylinder is covered with wire-cloth1 and as it revolves it takes with it a certain quantity of pulp in the form of a continuous sheet4 ,this sheet is taken on to the endless travelling felt ,f by the small couch roll ,e4 ,when it reaches the rolls ,c it is wound round the upper one1 from which it is removed when a sufficient thickness is obtained4 ,obtained in this form the pulp is readily transported4 ,the woods commonly employed are white pine and aspen4 ,the latter yields a pulp of a better colour1 but of inferior strength than the former4 ,paper containing mechanical wood pulp is very liable to become discoloured by the action of air and light1 the ligno-celluloses being much more readily acted upon than the celluloses isolated from them4 ,such fibre is1 moreover1 devoid of much felting power2 it has1 in fact1 little to recommend it but its comparative cheapness4 ,it is nevertheless used in large quantities1 some cheap papers being made entirely from it4 #aji ,,table ,,of ,,strength ,,of ,,caustic ,,soda ,,solutions 7#ae ,c4 #ei ,f47 7,t,,nnerman74 ---------------------------------------- ----------------- ,equivalent ,percentage ,specific ,degrees ,per cent4 of #fj per cent4 ,gravity4 ,twaddle4#aj ,na#b,o4 ,caustic ,soda4 ---------------------------------------- ----------------- #ajjdj #jhj #jcjb #jejc #ajjha #afb #jfja #ajja #ajafc #cbf #abji #bjae #ajbdf #dib #ahac #cjba #ajccj #ffj #bdah #djcj #ajdad #hbh #cjbb #ejcg #ajejj #ajjj #cfbf #fjdc #ajehg #aagd #dbca #gjea #ajfge #acej #dhce #hjei #ajgfd #aebh #eddj #ijfg #ajhee #agaj #fjdd #ajjgc #ajidh #ahif #ffdh #aajhj #aajdb #bjhd #gbec #abjij #aaacg #bbgd #gheg #acjie #aabcc #bdff #hdfb #adajc #aaccj #bffj #ijff #aeaaj #aadbh #bhef #ifgj #afaag #aaebh #cjef #ajbge #agabe #aafcj #cbfj #ajhgi #ahaca #aagcd #cdfh #aadhd #aiadj #aahda #cfhb #abjhh #bjadg #aaidh #chif #abfib #baaec #abjeh #daaf #acbig #bbafa #abagh #dcef #acija #bcagj #abbhj #defj #adejf #bdagg #abcib #dghd #aeaaj #beagj ---------------------------------------- ----------------- ,,note4--,it must be borne in mind that the above numbers refer only to solutions of pure caustic soda4 ,with liquors containing sodium chloride1 sulphate1 c41 the specific gravity will give an erroneous view of the amount of alkali present1 as these salts of course raise the gravity4 ,for example1 a liquor prepared by causticising a solution of recovered soda has a specific gravity of #aje 7#aj ,tw474 ,according to the above table this corresponds to #fjdc per cent4 of #fj per cent4 caustic4 ,tested by means of standard acid it showed #debj per cent4 ,too much reliance should therefore not be placed upon determinations of specific gravity1 but in important cases the actual amount of alkali should be determined by titration with standard acid4 ,footnote #aj3 ,to convert degrees ,twaddle into specific gravity1 multiply by #e1 add #ajjj and divide by #ajjj3 thus #g ,tw41 #g #e #ce #ajjj #ajjj7 #ajce 7#ajce sp4 gr4 #ajjj #cejj #cjjj #ejjj #ejjj #aaj ,,chapter ,,vii4 ,,bleaching4 ,the methods of bleaching being essentially the same for all pulps1 it will only be necessary to describe one in detail4 ,the process depends upon the use of a solution of calcium hypochlorite1 prepared by dissolving bleaching powder in water4 ,this solution is best prepared in a vessel provided with stirrers or agitators1 whereby a thorough mixture of the bleaching powder and water is obtained4 ,bleaching powder always contains a certain amount of free lime and calcium carbonate1 which remain undissolved in the water4 ,this should be allowed to settle to the bottom of the vessel1 and the clear liquor run off4 ,the residue may then be again treated with water1 or with weak liquor obtained by washing the residue4 ,if the washings are too weak to be conveniently used for bleaching1 they may be stored in a separate tank and used for dissolving fresh powder4 ,in this way a strong stock solution can be readily prepared1 the powder at the same time being thoroughly exhausted4 ,the washing should be repeated as frequently as possible1 after which the residue may be allowed to drain4 ,this operation is best conducted on a filter bed provided with an air-pump similar to that described in ,chapter ,,xii4 ,the residue is obtained in this way as a hard cake1 containing about #fj per cent4 of water4 ,if the above operations have been properly conducted1 it should not contain more than about #jbe per cent4 of chlorine4 ,the original powder should contain from #ccj to #cej per cent4 of 8available chlorine10 that is1 chlorine which is effective in the bleaching process4 #aaa ,owing to the ease with which it decomposes it should be kept cool and not exposed to the air4 ,if possible1 one or more large store tanks should be provided for the strong bleach liquor1 so that time may be given for the complete separation of the insoluble portions4 ,the liquor can be drawn off with a 8siphon0 pipe without disturbing the residue4 ,it is of the utmost importance that only clear liquor be used1 as a milky solution of calcium hypochlorite is much more sluggish in its action than one which is perfectly clear and bright4 ,a convenient strength for the stock solution is #f ,twaddle3 this corresponds to about half a pound of bleaching powder to the gallon4 ,the method of testing the powder and its solution will be described in ,chapter ,,xiv4 ,the washed and broken pulp is placed in the 8potcher0 together with the necessary quantity of bleaching liquor and as much water as is required to produce complete circulation of the mass4 ,in many mills the breaker itself answers the purpose of a potcher also4 ,the quantity of water should be kept as low as possible1 as it is found that by the use of strong solutions less bleaching powder is required than with weak solutions2 moreover1 less time is required to produce the effect4 ,on the other hand1 with very strong solutions1 the pulp is liable to be injuriously affected4 ,straw and esparto pulps are sometimes bleached in large potchers made of brick covered with cement4 ,the circulation of the pulp is produced by the action of paddles made of wood or1 preferably1 of iron4 ,many 8potchers0 are provided with steam pipes1 whereby the mass of pulp and liquor is heated4 ,this should be done with great care1 so as to avoid superheating in any part1 as this is certain to cause destruction of the fibre4 ,the better plan1 where it can be adopted1 is to uniformly heat the pulp before running in the bleach4 ,in certain cases the action of the calcium hypochlorite is #aab assisted and accelerated by the addition of either sulphuric or hydrochloric acids2 these combine with the lime and liberate hypochlorous acid1 which has a more rapid action than its calcium salt4 ,if the acid be added in too large quantity1 or of too great a strength1 it sometimes happens that instead of hypochlorous acid1 chlorine gas is given off1 part of which escapes into the air1 thus causing loss4 ,moreover1 the chlorine is liable to enter into combination with the fibre substance forming the yellow chlorination products described on p4 #ah4 ,this liability is greater in the case of highly lignified fibres1 such as wood or jute3 in these cases1 therefore1 the use of acids should be avoided4 ,when used the acid should be largely diluted with water and added gradually4 ,the best plan is to allow the action of the bleach to continue for some time1 only adding the acid when it is nearly exhausted4 ,in this way risk of damage to the pulp is avoided4 ,the diluted acid should be conveyed by a leaden pipe passing down to the floor of the potcher1 and perforated at its lower extremity4 ,other means of accelerating the action of the bleaching powder have been suggested1 such1 for example1 as the use of bicarbonate of soda1 which by double decomposition forms with the bleaching powder carbonate of lime and free hypochlorous acid4 ,it is1 however1 much too expensive an agent4 ,the amount of bleaching powder necessary to produce a good white colour differs materially with the fibre to be bleached1 and of course with the degree of resolution of the fibre substance in the preliminary treatment with caustic soda4 ,the following numbers may be taken to be approximations of the amount necessary to bleach well-boiled pulps3-- ,per cent4 ,powder calculated on ,unboiled ,fibre4 ,esparto #aj to #ae ,straw #g to #aj ,wood #ae to #bj #aac ,a well-boiled pulp should contain from #ij to #ie per cent4 of cellulose4 ,very excellent results are sometimes obtained by substituting sodium hypochlorite for the calcium compound4 ,this is done by decomposing a solution of bleaching powder with an equivalent quantity of either sodium sulphate or sodium carbonate4 ,the precipitate of calcium sulphate or carbonate is allowed to settle and the clear liquor run off4 ,such a solution is more sluggish in its action than one of calcium hypochlorite1 but it is more easily controlled1 and is less liable to injure any material treated with it4 ,the time necessary to produce a perfect bleach depends on the nature and condition of the pulp1 on the degree of concentration of the liquor1 and on the temperature at which the operation is conducted4 ,some paper-makers prefer to extend the bleaching over a considerable period of time1 but this involves the employment of a larger system of 8potchers10 which in many instances is an objection4 ,if this method is adopted1 especially in the case of straw or esparto1 the action of the paddles or roll should be stopped1 as otherwise the fibres are liable to felt together in the form of small grains1 which sometimes escape the action of the beating roll1 and occasionally find their way into the paper1 causing an unevenness of surface4 ,by giving longer time to the bleaching there is less risk of damage to the fibre1 and consequently a greater yield of bleached pulp4 ,the action of the bleaching solution should1 as far as possible1 be confined to the non-cellulose portions of the fibre4 ,a certain action on the cellulose itself invariably takes place1 but it should be reduced to a minimum4 ,the action of bleach upon cellulose has been indicated in ,chapter ,i41 p4 #aj4 ,for further information on this subject the reader is referred to the #8,journal of the ,society of ,chemical ,industry1' #ahhd1 ,april #bi and ,may #bi4 ,a very good method of bleaching consists in a preliminary treatment in the ordinary way in the potcher1 followed by a prolonged steeping in tanks4 #aad ,in the case of pulps which are very difficult to bleach1 the action can be greatly assisted by washing out the products of the bleaching action1 treating the pulp for a short time with a weak alkaline solution1 again washing1 and then repeating the bleaching process4 ,in this way very refractory pulps can easily be bleached4 ,even an intermediate washing with water is useful4 ,in most cases1 where a fairly good colour has been obtained by the use of bleaching powder alone1 the colour is greatly improved by a souring or treatment with weak hydrochloric acid1 or1 better still1 with solution of sulphurous acid4 ,or the bleaching may be conducted in two or more operations with intermediate treatments with acid4 ,all these modifications1 however1 are more or less troublesome1 and should only be resorted to when the ordinary method fails4 ,after bleaching1 a certain quantity of calcium hypochlorite always remains in the pulp4 ,it may be removed in the potcher itself1 or when the pulp reaches the beater4 ,in any case1 the methods adopted are the same4 7,see p4 #abg47 ,in some mills it is the practice to free the bleached pulp from the products of the decomposition of the bleach by pressing the pulp in hydraulic presses1 or by draining in vats provided with perforated bottoms4 ,or the pulp may be made to pass through a pulp-saver 7see ,fig4 #eb1 p4 #aee47 ,chlorine gas as a bleaching agent has been almost entirely superseded by the more manageable calcium hypochlorite4 ,its employment is open to the serious objection indicated before1 viz4 the liability to form difficultly removable chlorine compounds4 ,its use as a disintegrating agent has already been alluded to 7see p4 #ajb74 ,a process has lately been invented 7,english patent1 ,no4 #aa1ccc1 #ahhd71 by ,prof4 ,lunge1 which involves the use of acetic acid4 ,the quantity required is1 however1 very small1 as during the process of bleaching it becomes regenerated4 ,the free lime in the bleaching powder solution should first be #aae nearly neutralised with a cheaper acid1 such as hydrochloric or sulphuric1 followed then by the addition of the acetic acid4 ,this process1 we are informed1 gives excellent results with high-class material1 such as the best cotton and linen rags2 it is1 however1 not to be recommended for such materials as straw or esparto4 ,for the bleaching of rags the process invented by ,thompson 7,english patent1 ,no4 #eie1 #ahhc7 has proved very effective4 ,the method consists in saturating the material with a weak solution of bleaching powder1 and then exposing them to the action of carbonic acid gas4 ,in this way the bleaching action is made very rapid and effective4 ,electrolytic ,bleaching4--,various attempts have from time to time been made to bleach by means of electricity--that is to say1 by means of the products of the electrolysis of solutions of alkaline chlorides and the chlorides of the alkaline earths4 ,the only process which has been to any extent developed is that of ,m4 ,hermite4 ,this process is based upon the electrolysis of a solution of magnesium chloride1 this salt having been found to give the most economical results4 ,the solution1 at a strength of about #be per cent4 of the anhydrous salt 7,mg,cl#b71 is electrolysed until it contains the equivalent of about #cj grms4 chlorine per litre4 ,this solution is then run into the 8poacher0 containing the pulp to be bleached2 a continuous stream is then kept up1 the excess being removed by means of a drum-washer4 ,this excess1 which after being in contact with the pulp in the engine is more or less deprived of its bleaching properties1 is then returned to the electrolysing vat1 where it is again brought up to the normal strength4 ,the electrolysing vat consists of a rectangular vessel of slate or other suitable material4 ,the negative electrode may be constructed of zinc2 for the positive it is necessary to employ platinum4 ,the electrolysed solution has been found to possess very remarkable properties1 which have considerable bearing upon the economy of the process4 ,if a solution be taken of equal #aaf oxidising efficiency with one of calcium hypochlorite1 as indicated by the arsenious acid test 7see p4 #bjf71 it is found that the former possesses greater bleaching efficiency than the latter in the proportion of #e to #c4 ,moreover1 the bleaching is much more rapid1 and the loss of weight which the substances undergo is less1 for equal degrees of whiteness obtained4 ,it has been shown that by the electrolytic method the bleaching of paper pulp can be effected at nearly one-half the cost of bleaching powder4 ,the process is now being industrially carried out4 ,those interested in the subject are referred to a paper by the authors in the #8,journal of the ,society of ,chemical ,industry' for ,april #ahhg4 #aag ,,chapter ,,viii4 ,,beating4 ,the bleached pulp is now ready for the final treatment4 ,if it were attempted to make paper from the pulp in the state in which it leaves the 8potchers0 or 8steeping0 chests1 it would be found to be wanting in evenness of texture and uniformity of surface4 ,this result can only be secured by an elaborate process of comminution or disintegration4 ,this is in effect the result produced by the action of the 8beaters40 ,they resemble in general appearance the breaking engines previously described2 the roll1 however1 carries more knives1 and it is usually let down much nearer to the bed-plate4 ,in the case of fibrous substances1 whose ultimate fibres are relatively short 7see table1 p4 #ci71 it is only necessary to split up the filaments into their constituent fibres3 esparto1 straw1 and wood are of this class4 ,in the case of straw1 the disintegration is for the most part accomplished in the boiling and bleaching processes1 and therefore but little work devolves upon the beater4 ,esparto and wood require a certain amount of beating1 but this should be regulated to the drawing asunder of the individual fibres1 any cutting of the fibres being carefully avoided4 ,this is accomplished by adjusting the distance of the roll from the bed-plate1 so that by the friction of the fibres upon themselves1 when passing over the plate1 a kind of rubbing or 8brushing0 is produced4 ,if a carefully-made paper of esparto or wood be examined by the microscope1 it will be found that the majority of the fibres preserve the pointed or slightly rounded ends #aah characteristic of bast cells4 ,on the other hand1 it is obvious that cotton1 whose ultimate fibres have a length of #bj to #dj mm41 and flax 7#be-cj mm471 with other similar fibres1 will require to be broken up into short fragments in order to develop to the fullest the felting property of the pulp4 ,not only are the fibres reduced to the most favourable dimensions1 but in cotton and linen a further contributory advantage accrues2 for on account of the internal structure of the ultimate fibres they tend to split up at the point of rupture into a number of fibrill1 which1 in the case of cotton1 take the form of a network2 and in case of linen1 are seen as a bundle of distinct fibres parallel to and continuous with the fibre4 ,this gives to ends of the fragments a ragged contour1 which has considerable influence on the felting power of the pulp1 and therefore on the strength of the paper into which it is made4 ,with these fibres1 therefore1 the 8cutting0 as distinguished from the 8breaking0 action should be avoided as much as possible1 otherwise the effect described above will not be produced1 and the fibres will show instead a clean cut4 ,the appearance shown by cotton and linen pulp1 when thoroughly 8beaten0 and ready to be made into paper1 is given in the frontispiece1 which is taken from the author's micro-photographs4 ,the 8half-stuff0 is furnished to the 8beater10 or 8beating0 engine as it is sometimes called1 previously partially filled with water4 ,the furnishing is done in successive portions1 the first being allowed to mix thoroughly with the water before another lot is added4 ,this is continued until the mass is so thick that it will only just turn round in the beater under the action of the 8roll40 ,owing to the construction of the beater it frequently happens that a portion of the pulp lodges in the corners1 from which the beaterman removes it by means of a wooden paddle1 which also serves to push forward the pulp to the roll in case the motion is inclined to be sluggish4 ,the proportion of water to pulp should not be too high1 otherwise the beating is not so effective2 at the same time1 #aai if the mass is allowed to get too thick1 imperfect circulation results4 ,the operation of 8beating0 occupies a considerable time1 and consumes a large amount of power4 ,cotton and linen rags naturally take longer--in some cases as much as ten hours is given to the operation4 ,esparto1 on the other hand1 can be sufficiently disintegrated in from two to four hours4 ,wood pulp requires very gentle beating2 it is therefore necessary to prolong the time to about six hours4 ,these differences in the duration and method of beating should be borne in mind when pulps of different natures are mixed together in the same beater1 as is frequently the case4 ,it is better1 with very dissimilar fibres1 to 8beat0 each separately1 and only to mix them in the stuff-chests4 ,this1 however1 is open to the objection that the pulps may be insufficiently mixed4 ,the length of fibre to which pulps should be reduced depends to some extent upon the kind of paper to which it is to be applied4 ,the authors have examined a number of papers by well-known makers1 and find the dimensions in millimetres of various pulps to be as follows3-- ,fibre4 ,maximum4 ,minimum4 ,mean4 ,cotton #acb #jbc #jge ,linen #abj #jbj #jgf ,esparto #adj #jdj #ajj ,straw #aej #jej #jhh ,wood #bfj #ajj #bjj ,wood and straw pulp1 when imported in the form of dry sheets1 may1 before being beaten1 be conveniently disintegrated and thoroughly mixed with water by means of the edge-runner described under 8,broke ,paper10 p4 #ajd1 ,fig4 #bh4 ,in making the finer kinds of paper1 the roller bars or knives1 instead of being made of steel are made of bronze1 thus any contamination with oxide of iron is avoided4 ,this is especially liable to take place in case of steel knives when the beater has been allowed to stand for some time4 #abj ,the inside of the heater itself is often lined with lead1 a material which is not liable to oxidize1 and which can very readily be cleaned4 ,when a beater has been running for some time the knives of the roll and the bed-plate become worn and so far reduced that they must be taken out and re-cut4 ,the bed-plate is removed1 firmly fixed in the bed of a planing machine1 and the edges trimmed by means of a chisel1 so as to cut the knives at the proper angle4 ,the roll and bed-plate are shown in section in ,fig4 #cb4 ,fig4 #cc is a plan of a bed-plate1 and ,fig4 #cd illustrates the manner in which the knives are fixed4 ,illustration3 ,,fig4 #cb4 ,it will be seen that the knives in the bed-plate are placed so that they do not lie parallel with those of the roll4 ,this arrangement imitates to some extent the action of a pair of scissors4 ,occasionally the knives are slightly bent1 so as to form a very obtuse angle4 ,bed-plates so fitted are called #aba 8knee-plates40 ,they are largely used in ,america1 but not much in this country4 ,illustration3 ,,fig4 #cc4 ,illustration3 ,,fig4 #cd4 ,to obviate the necessity of removing the roll1 a small machine has been devised whereby the knives can be cut in situ4 ,this machine1 which can be firmly fixed between the mid-feather and the side of the beater1 consists of a small steam-engine which actuates a movable cutter1 which is made to pass to and fro horizontally along the edge of each knife in succession4 ,the engine is supplied with steam by a piece of strong flexible rubber tubing4 ,the ordinary form of beater contains only one roll1 though some have been constructed containing two or even four rolls4 ,in ,america1 beaters of a totally different construction are much in vogue4 ,the most important of these are the ,jordan and ,kingsland beaters1 so called from the names of the inventors4 ,the former consists essentially of a roll in the shape of a truncated cone1 fitted with knives in the usual way1 revolving in an iron box of corresponding shape1 furnished with knives placed in the direction of its length1 but at slightly different angles4 ,the half-stuff enters the beater at the narrow end through a box provided with an #abb arrangement for regulating the flow1 and is discharged by two or more openings in the cover at the wider end4 ,the ,kingsland engine consists of a circular chamber1 the sides of which are covered with knives1 and between which a circular plate1 also furnished with knives1 revolves4 ,the pulp enters through a pipe in the centre of one of the sides of the chamber1 and flows out through an opening in the opposite side4 ,another form of beater is that invented by ,s4 ,l4 ,gould4 ,the only essential difference between it and the ,kingsland beater is that1 instead of having a plate which revolves vertically against two stationary ones1 the plate1 which is placed horizontally1 is furnished with knives on one side only1 and revolves upon but one fixed plate1 much in the same way as a pair of millstones4 ,the half-stuff supplied to these forms of beater is generally disintegrated to a greater extent in the breaker than is the case with those of the ordinary construction1 as it is necessary to make it flow easily through them1 and this could not be done if the fibres were kept long4 ,a single passage of the pulp through the beater is sufficient to beat it up ready for making into paper4 ,the chief advantages claimed for them is that they are more economical1 both of time and power2 also that the pulp is more regularly beaten4 ,certain new forms of beaters have lately been introduced in this country1 and are rapidly gaining in favour1 chiefly on account of the saving of driving power1 and the space occupied1 compared with the amount of 8stuff0 they are capable of beating4 ,fig4 #ce shows the construction of ,forbes' patent engine1 as manufactured by ,messrs4 ,g4 ,w4 ,bertram1 of ,edinburgh4 ,this beater is divided into three channels4 ,the rolls1 one of which is shown uncovered1 are placed in the outer channels1 while in the centre one the mixing and circulating wheel a is placed1 the peculiar construction of which enables it to throw the pulp alternately into the two outer channels1 from whence1 after passing under the rolls again1 it enters the central channel at the other end of the beater4 #abc ,in ,umpherston's patent engine great economy of space is effected by causing the pulp to travel over and under the backfall 7a1 ,fig4 #cf74 ,another advantage is that the stuff circulates freely with less water than in the ordinary forms1 thus increasing its output4 ,it is also claimed that the pulp is beaten with less power1 and as it is less liable to lodge in corners it is more evenly beaten4 ,illustration3 ,,fig4 #ce4 ,the construction of the engine will be readily understood by reference to ,fig4 #cf4 ,the direction which the stuff takes is indicated by the arrows4 ,cooke and ,hibbert's beater1 as manufactured by ,messrs4 ,masson1 ,scott and ,bertram1 resembles1 to a certain extent1 ,gould's engine1 previously described2 it differs from it1 however1 in that the discs are placed vertically1 instead of horizontally4 ,moreover1 the general construction of the beater more nearly resembles those in ordinary use4 ,fig4 #cg1 which shows it in plan and in section at the line ,d ,e1 illustrates its construction4 ,illustration3 ,,fig4 #cf4 ,illustration3 ,,fig4 #cg4 ,the shaded portions ,a represent the stationary disc4 ,it is furnished for about two-thirds of its circumference with steel bars or knives1 placed tangentially4 ,b represents the #abe revolving disc on which similar knives are placed radially round the whole circumference4 ,the direction that the pulp takes is indicated by the arrows4 ,after passing between the plates it is thrown violently into the trough at ,g1 the result being that it is very thoroughly mixed4 ,the distance between the plates can be regulated by means of the gearing ,h4 ,the engine is driven by the pulley ,c fixed on the shaft ,f4 ,it is claimed that by means of this form of beater a great saving in time and power is effected1 and that moreover the pulp is obtained in a more even condition4 ,illustration3 ,,fig4 #ch4 ,illustration3 ,,fig4 #ci4 ,the quality of the water used to furnish the engine is a matter of very great importance1 especially in the manufacture of high-class papers4 ,above all it should be free from suspended matter1 and from dissolved iron2 the former finds its way directly into the paper1 and the latter is liable to become precipitated in the pulp as oxide1 thus injuriously affecting its colour4 ,careful settling and filtration are sufficient to eliminate insoluble matter2 soluble impurities are more difficult of removal2 therefore the water should1 if possible1 be free from them4 ,in most mills settling ponds are provided1 for the purpose of removing suspended matter1 and in addition it is usual to employ woollen filter-bags #abf fastened to the nozzle of the pipe that supplies the beaters with water4 ,for methods of purifying water see p4 #baa4 ,the beaters are generally driven from a separate engine1 and are connected with it by a system of spur-wheels1 pinions1 and belts4 ,messrs4 ,g4 and ,w4 ,bertram have lately introduced a system of direct driving of beaters1 whereby a great saving in power is effected4 ,it is illustrated in plan and elevation in ,figs4 #ch and #ci4 ,the crank-shaft of the engine is coupled direct on to the main driving-shaft4 ,large pulleys are keyed on to this shaft1 from which the power is taken directly on to the pulleys connected with the rolls4 #abg ,,chapter ,,ix4 ,,loading1 ,,sizing1 ,,colouring1 ,,etc4 ,the bleached half-stuff as it leaves the steeping chests usually contains an excess of bleaching liquor1 which can be removed in two ways1 viz4 by washing or by decomposition with an 8antichlor40 ,the first method has the advantage of not only removing the bleach1 but of also eliminating the chloride of calcium1 partly existing ready formed1 and also that resulting from the decomposition of the calcium hypochlorite originally present in the bleach4 ,on the other hand1 this method takes some time1 and consumes a large amount of water1 which in some mills is a matter of considerable importance4 ,for this purpose1 many beaters are provided with one or more drum washers 7see ,fig4 #cf74 ,an additional objection to this method lies in the fact that a certain quantity of fibre passes through the meshes of the wire-cloth covering the washers1 and is thus lost4 ,the more usual plan is to remove the bleach by decomposing it with an 8antichlor40 ,the substance generally employed for this purpose is sodium hyposulphite1 or thiosulphate as it is now called1 which1 in presence of calcium hypochlorite1 is oxidized to sodium sulphate1 the latter being reduced to calcium chloride4 ,double decomposition then takes place between these salts1 with the formation of calcium sulphate and sodium chloride4 ,the reactions which take place may be expressed by the following equation3-- #b 7,ca7,cl,o7#b7 ,na#b,s#b,o#c ,h#b,o #b ,ca,s,o#d #b ,h,cl #b ,na,cl4 ,calcium ,sodium ,water4 ,calcium ,hydrochloric ,sodium hypochlorite4 thiosulphate4 sulphate4 acid4 chloride4 #abh ,the above decomposition does not accurately represent the action of bleach upon sodium thiosulphate4 ,if the solutions employed are very dilute1 the decomposition may take place in another direction1 viz43-- ,ca7,cl,o7#b #d ,na#b,s#b,o#c ,h#b,o #b ,na#b,s#d,o#f #b ,na,cl ,calcium ,sodium ,water4 ,sodium ,sodium hypochlorite4 thiosulphate4 tetrathionate4 chloride4 #b ,na,o,h ,ca,o4 ,caustic soda4 ,lime4 ,at the particular degree of dilution which occurs in a beater1 the bleach is decomposed almost entirely according to the first of the equations2 from which1 on calculating1 it will be seen that #aeh parts of sodium thiosulphate are equivalent to #bhf parts of calcium hypochlorite4 ,as commercial sodium thiosulphate contains #cfc per cent4 of water1 and bleaching powder #gj per cent4 of calcium hypochlorite1 on the basis of #ce per cent4 available chlorine it follows that #bdh parts of the former are required to neutralize #dji parts of the latter4 ,within the last few years other forms of 8antichlor0 have been introduced1 such1 for example1 as the various sulphites4 ,the most important of these is sodium sulphite1 which has been manufactured by a patent process at a cheap rate1 by ,gaskell1 ,deacon1 ,co41 ,widnes4 ,their product contained as much as #ge per cent4 of ,na#b,,so#c1 ordinary crystallized sodium sulphite containing only #ej per cent4 ,sulphites are converted by the action of bleach into sulphates1 thus3-- ,ca7,o,cl7#b #b ,na#b,,so#c ,ca,s,o#d #b ,na#b,,so#d #b ,na,cl ,calcium ,sodium ,calcium ,sodium ,sodium hypochlorite4 sulphite4 sulphate4 sulphate4 chloride4 ,from this equation1 it will be seen that #beb parts of sodium sulphite will neutralize #adc parts of calcium hypochlorite1 or #bjdc parts of bleaching powder4 ,assuming that crystallized sodium sulphite contains #ej per cent4 ,na#b,,so#c1 the same amount of bleach would require #ejd parts4 ,as ,messrs4 ,gaskell1 ,deacon ,co4's sulphite contains #ge per cent4 ,na#b,,so#c1 only #ccf parts are needed4 ,comparing these numbers with #abi those given above for sodium hyposulphite1 it will be seen that #bjde parts of bleach require for neutralisation #abi parts of sodium thiosulphate and #ejd parts of crystallised sodium sulphite1 or #ccf parts of the stronger product4 ,sodium sulphite is preferred to sodium thiosulphate by some paper makers1 notwithstanding the fact that even in its most concentrated form1 nearly three times as much is required to produce a certain result4 ,it is said that when it is used the wire cloth of the machine is preserved for a longer time than if sodium thiosulphate is employed4 ,this may be due to the fact that with the latter a certain amount of free acid is always formed1 which of course would act injuriously on the wire2 whereas1 when sodium sulphite is used1 the products of decomposition are neutral salts without any action upon metals4 7,see the above equations47 ,a very cheap 8antichlor0 may be prepared by boiling together lime and sulphur4 ,one hundred and sixty-eight parts of lime1 made into a milk with water1 are heated to boiling in an iron vessel4 ,three hundred and eighty-four parts of flour of sulphur or ground sulphur are then added in small quantities at a time1 and the boiling continued until the whole is dissolved4 ,the liquid which is now of a deep yellow colour1 is allowed to settle and cool and is then ready for use4 ,it contains a mixture of calcium thiosulphate and calcium pentasulphide1 the latter compound giving to it its deep yellow colour4 ,the following equation represents the action which takes place between the lime and the sulphur3-- #c ,ca,o #ab ,s ,ca,s#b,o#c #b ,ca,s#e ,lime4 ,sulphur4 ,calcium ,calcium thiosulphate4 pentasulphide4 ,the decomposition which takes place when the mixture is acted upon by calcium hypochlorite may be represented as follows3-- #b 7,ca,s#b,o#c #b ,ca,s#e7 #i 7,ca7,o,cl7#b7 #f ,ca,s,o#d ,calcium ,calcium ,calcium ,calcium thiosulphate4 pentasulphide4 hypochlorite4 sulphate4 #ah ,s #i ,ca,cl#b ,sulphur4 ,calcium chloride4 #acj ,from this it is seen that a large quantity of free sulphur is formed1 which is precipitated as a fine yellowish powder in the fibre4 ,this not only affects the colour of the pulp1 but is objectionable on account of its liability1 in contact with the hot cylinders of the paper machine1 or by the action of moisture over a long period of time to become oxidised to sulphuric acid1 which undoubtedly1 even if present only in very small quantities1 has an injurious effect upon the finished paper4 7,see hydracellulose47 ,this property of sulphur and its action upon cellulose may be shown by the following experiment4 ,take a piece of water-leaf paper1 rub into it a mixture of flour of sulphur and water4 ,if the paper thus treated be rapidly dried1 it will be found to be weakened or even slightly charred in those portions which have been in contact with the sulphur4 7,see also ,chem4 ,soc4 ,journ41 p4 #bdi1 #ahgi47 ,whichever variety of 8antichlor0 is used an excess should be carefully avoided1 as all act more or less upon the size and colouring matter added to the pulp subsequently4 ,the proper method is to run in small quantities of a solution of the antichlor at a time1 testing the pulps1 after allowing a few minutes for complete admixture after each addition4 ,the test is made by immersing a piece of iodide of potassium and starch paper1 which will be turned blue so long as any calcium hypochlorite is present4 ,these papers are made as follows3-- ,three grms4 of starch are ground up with a small quantity of water and poured into #gjj cc4 of boiling water1 and to the solution #a grm4 of iodide of potassium and #je grm4 carbonate of soda are added4 ,sheets of white paper1 water-leaf in preference1 are now soaked in the solution and dried4 ,in presence of calcium hypochlorite1 iodine is liberated from the potassium iodide1 and acting upon the starch forms with it a characteristic blue colour4 ,loading4--,it is usual1 except in the case of papers of the very highest quality1 to add to the pulp a quantity of some cheap loading material1 such as china clay1 or for the better #aca qualities of paper1 8pearl-hardening10 or sulphate of lime4 ,the addition of clay in moderate quantity can hardly be looked upon as an adulteration1 since it serves to fill up the pores of the paper1 and enables it to take a good surface in the subsequent operations of calendering4 ,moreover1 it enables the manufacturer to meet the demand for cheap papers with some chance of remuneration to himself4 ,if added largely1 it of course tends to weaken the paper4 ,china clay or kaolin is sold in the form of large lumps of a white or yellowish-white colour4 ,it is formed by the gradual disintegration of felspar by means of the action of air and water1 and consists essentially of a silicate of aluminium4 ,its quality depends upon its whiteness and its freedom from coarse micaceous particles4 ,it is usually prepared for admixture with the pulp by making it into a fine cream with water in a vessel provided with stirrers2 it is then passed through a fine sieve in order to remove any impurities it may contain1 and is then run into the beater4 ,the clay or other filling material is usually run into the beater as soon as the latter is charged with pulp1 so that by the time the beating operation is concluded1 a perfect admixture of pulp and clay is effected4 ,sulphate of lime1 or 8pearl-hardening10 is usually sufficiently pure to put direct into the engine4 ,it is made by decomposing a solution of calcium chloride1 with sulphate of soda1 and is precipitated as a fine brilliantly white powder1 consisting of ,ca,s,o#d #b ,h#b,o4 ,two distinct forms of precipitated calcium sulphate are met with in commerce1 differing from each other by their microscopical features1 the one consisting of flat tabular crystals 7,fig4 #da71 the other of fine needles 7,fig4 #db74 ,another form1 erroneously called precipitated pearl-hardening1 is also sold3 it consists of the finely ground native mineral4 ,illustration3 ,,fig4 #dj4 ,illustration3 ,,fig4 #da4 ,some of the finer qualities of paper are made without addition of any loading material whatever1 though such papers are of course the exception4 ,the proportion of clay or #acb other material that can be put into a fibre depends to a certain extent upon the nature of the fibre1 and upon the degree of fineness to which it is reduced in the beater4 ,the amount added by different makers varies considerably1 from #acc two or three per cent4 to twenty1 and even in rare cases to thirty per cent4 ,illustration3 ,,fig4 #db4 ,illustration3 ,,fig4 #dc4 ,a new loading material called 8agalite0 has been lately introduced1 possessing certain advantages over china clay1 #acd or calcium sulphate4 ,agalite is a mineral of the nature and chemical properties of asbestos3 it consists of nearly pure magnesium silicate4 ,its structure is more or less fibrous1 like that of asbestos1 which1 as is well known1 can be spun and woven and even made into paper1 and it therefore1 when added to a paper1 forms a part of the fabric itself4 ,it is even claimed that it assists in keeping back some of the finer fibres that invariably find their way through the meshes of the wire cloth1 and it is said that #ij per cent4 of the amount added to the engine is found in the paper4 ,in the case of china clay it is well known that only from #dj to #fj per cent4 is actually 8carried0 by the pulp4 ,figs4 #dj1 #da1 #db1 and #dc show the appearance of china clay1 pearl-hardening1 and agalite when viewed under the microscope1 magnified #bjj times4 ,the nature of agalite is such that it assists the paper in taking a high finish4 ,this is probably due to its 8soapy0 nature1 a feature which is characteristic of asbestos1 ,french chalk1 8soap-stone10 and other magnesium silicates4 ,illustration3 ,,fig4 #dd4 ,when papers contain such excessive quantities as #ae or #bj per cent4 of clay1 it cannot be to the advantage of the consumer1 and should be looked upon as an adulteration4 ,it is a matter of some importance to be able to determine rapidly and accurately the amount of mineral matter in a paper4 ,the usual method is to ignite a weighed quantity of the paper in a platinum crucible until the ash so obtained is either white or a very pale grey4 ,from the weight of the ash1 the percentage of mineral matter is easily calculated4 ,the following is a very convenient plan in cases where a platinum crucible or dish is not obtainable3--,take a weighed piece of the paper to be examined1 from #b to #d in4 square1 according to the thickness1 roll it into a narrow hollow cylinder4 ,round this wind a weighed piece of platinum wire about #a_/ej in4 thick1 as in ,fig4 #dd4 ,hold this by means of a pair of crucible tongs in the flame of a ,bunsen burner until it is completely burned4 ,if the wire is carefully wound round1 and especially if the roll of paper is made conical1 the ash will be securely held in #ace position4 ,those who do not possess a chemical balance of the ordinary form will find a convenient substitute1 which will answer the purpose of weighing the paper and ash with sufficient accuracy1 in the spiral balance invented by ,prof4 ,jolly#aa illustrated in ,fig4 #dd4 ,it consists of a spiral of hard wire ,a1 which is suspended in front of a mirror ,b1 upon which millimetre divisions are marked4 ,a small float ,d1 dipping under the surface of the water in the vessel ,e1 is provided for the purpose of steadying the spiral and allowing it to come quickly to rest4 ,the balance is provided with a light pan made of a thin plate of mica1 and suspended by very thin platinum wires4 ,for the present purpose1 however1 the pan is not necessary1 and it can be replaced by the roll of paper and platinum coil as shown in the drawing4 ,footnote #aa3 ,this balance can be obtained from ,nalder ,bros4 ,co41 ,westminster4 ,the method of using is exceedingly simple1 as the increase in the length of the spiral is in direct ratio to the increment of weight4 ,the position of the spiral is ascertained by placing the eye in a direct line with the small glass bead ,c and its image in the mirror1 and noting the corresponding division on the scale4 ,the position of the bead can be altered so as to bring it to any desired point on the scale by raising or lowering the upright rod ,f1 which is kept in position by the screw ,g4 ,the balance stands on a foot provided with levelling screws4 ,it is evident that where proportional weights only are required it is not necessary to know the value of the spiral1 but if the balance is to be used to ascertain actual weights1 the coefficient of the spiral must first be determined4 ,this is done by noting the increase in length after the addition of a one gram weight4 ,the spirals are made of different thicknesses of wire1 which of course give varying degrees #acf of sensibility3 the most useful is one which gives with one gram an extension of #ajj millimetres3 one mm4 being therefore equivalent to one mgrm4 ,the following experiment will illustrate the method of using the balance and of calculating the results of a determination of the amount of mineral matter in a paper3-- ,position of bead on scale #ajj mm4 ,position of bead after attaching platinum wire #aea ,position of bead with wire and roll of paper attached #bjj ,weight of paper expressed as millimetres #bjjaea #di ,position of bead with wire and ash attached #aefe ,weight of ash expressed as millimetres #aefeaea #ee ,weight of paper ,weight of ash ,percentage of expressed in expressed in ash in millimetres4 millimetres4 paper4 #di 3 #ajj 33 #ee 3 #aabbd ,in order to ascertain the percentage of mineral matter actually added to a paper it is necessary to deduct from the amount of ash obtained a certain quantity due to the mineral matter in the fibre of which the paper is composed4 ,this amount varies with each particular fibre1 and with the method by which it has been prepared4 ,the following table gives the percentage of ash yielded by the various pulps in a perfectly bleached state4 ,in all cases the fibres were previously treated with a dilute solution of hydrochloric acid1 in order to remove any carbonate of lime or other bodies which might have been introduced in the boiling and bleaching processes3 the percentages are calculated on the dry substances3-- ,pulp from linen rags #be ash per cent4 ,pulp from cotton rags #aj ,pulp from esparto #ej ,pulp from straw 7soda process7 #dhj ,pulp from straw 7,leunig process7 #acf ,pulp from wood 7soda process7 #ej ,pulp from wood 7bisulphite process7 #jf ,pulp from wood 7mechanical7 #dj ,if the paper contains calcium sulphate the ash obtained may consist partly of calcium sulphide1 due to the reducing action of the carbon found on ignition1 and the amount will #acg therefore not represent the true amount added4 ,the ash should be moistened with a few drops of sulphuric acid1 and again ignited1 in order to reconvert it into calcium sulphate4 ,it should also be borne in mind that the sulphate of lime as present in the paper is combined with two atoms of water ,ca,s,o#d #b ,h#b,o1 and therefore that every part of calcium sulphate obtained represents #abf parts of 8pearl-hardening0 actually added4 ,sizing4--,papers that are intended to be written upon with ink1 and also most printing papers1 require to have the interstices of the fibres filled up with some material which will to a greater or less extent resist the action of water1 and thus prevent the ink or other liquid applied to them from 8running40 ,this may be accomplished in two ways1 viz41 by 8engine-sizing0 and 8tub-sizing02 the former is so called because it is performed in the beating engine itself1 the latter being done on the finished paper1 as will be subsequently described4 ,engine-sizing consists in precipitating a compound called resinate of alumina in the pulp4 ,this compound when dried has the property of being with difficulty wetted with water4 ,in order to obtain a thorough mixture of this compound with the fibre it is formed in the engine by adding an aqueous solution of rosin-soap to the pulp1 and when this is intimately mixed with it1 running in a solution of alum4 ,rosin 7colophony7 consists of a mixture of pinic and sylvic acids1 which1 when heated with a solution of carbonate of soda1 combine with the alkali to form a soap1 carbonic acid being evolved4 ,the soap is prepared in the following manner3-- ,ordinary rosin1 the quality depending upon the quality of paper1 is boiled in a jacketed pan for from two to three hours with a solution of carbonate of soda1 until a sample of the soap formed is completely soluble in water4 ,the quantity of carbonate of soda 7,na#b;,,co#c #aj ,h#b,o7 required is about #cj per cent4 of the weight of the rosin4 ,it is usual to employ crystallised carbonate of soda 7soda-crystals71 but #ach soda-ash of good quality1 or even caustic soda1 might very well be employed1 in which case of course the proportion would be different4 ,a very convenient form of carbonate of soda has lately been introduced by ,messrs4 ,gaskell1 ,deacon ,co41 which goes by the name of 8,crystal ,carbonate40 ,it is obtained in the form of minute crystals of the mono-hydrate1 ,na#b;,,co#c ,h#b,o4 ,it contains #ej per cent4 of alkali 7,na#b,o71 and possesses this advantage over soda-ash1 that is dissolves readily in water without forming a hard cake4 ,it is much cheaper in proportion than soda crystals1 as the expense of crystallisation and carriage is saved4 ,the latter contain only #bafh per cent4 ,na#b,o1 #fbic per cent4 of their weight consisting of water of crystallisation4 ,one hundred parts of soda crystals are equivalent to #dccf parts of the 8,crystal ,carbonate40 ,an excess of soda should be carefully avoided1 as it consumes an equivalent quantity of alum 7see below73 on the other hand1 it is very essential that the rosin should be completely dissolved1 otherwise small particles are sure to find their way into the pulp1 and would form clear transparent specks in the finished paper4 ,the boiling being completed1 the charge is run off into iron tanks and allowed to settle2 the soap forms a semi-solid mass1 while a dark-coloured liquor1 containing the impurities of the rosin1 rises to the surface1 and can thus be removed4 ,the soap so purified is next dissolved in hot water containing a small quantity of carbonate of soda1 in case complete solubility has not been attained1 and is then mixed with a quantity of starch paste prepared in a separate vessel by dissolving starch in boiling water4 ,the mixture is then carefully sieved and is ready for use4 ,the proportion of starch to rosin differs in nearly every mill1 and also the quantity of size to be added to the beater varies according as the paper is required to be soft or hard-sized4 ,about #c parts of starch to #a of rosin1 and between #c or #d lbs4 of the mixture to #ajj lbs4 of pulp may be considered an average quantity4 ,some manufacturers prefer to add the #aci starch and rosin size to the engine separately2 others again do not dissolve the starch in water1 but merely make it up to a thin paste1 in which state it is added to the pulp4 ,this method is employed by makers of very fine papers1 as it is said to give a certain feel to the paper which cannot be obtained in any other way4 ,the method is costly1 as only a small proportion of the starch added is actually found in the paper4 ,some papers1 which are not intended to be sized1 such as blotting and filter-papers1 are made with the addition of starch only1 this being used to bind the fibres together to some extent4 ,the presence of the starch does not prevent the paper from being absorbent4 ,papers which are intended to be tub-sized only are usually made up with a small quantity of starch1 and are sometimes sized to a small extent with rosin also4 ,the addition of a certain amount of ordinary soap to the rosin soap is said to give good results2 it enables the paper to take a higher finish when calendered4 ,sizing with animal size 7gelatine71 or ,tub-sizing as it is called1 will be described in ,chapter ,x4 ,the mixture of size and starch may be added directly to the engine1 or it may be previously dissolved in water2 the latter method is perhaps preferable4 ,after allowing it to mix thoroughly with the pulp1 a solution of alum is run in4 ,it is made up with boiling water in either lead or copper tanks4 ,iron or zinc vessels must be avoided1 as the solution acts rapidly on these metals4 ,alum consists of a double sulphate of aluminium and potassium or ammonium1 ,al#bc ,,so#d1 ,k#b,,so#d #bd ,h#b,o2 its function being to form with the rosin acids insoluble soaps which are precipitated in intimate mixture with the pulp1 the sulphate of potash taking no part in the reaction4 ,the choice of a suitable alum is a matter of very great importance2 it should be free from excess of sulphuric acid and from iron4 ,the former is deleterious on account of its action upon the colouring matter used to tone the paper1 some colours being completely discharged by it2 and because #adj of its effect upon any metal work with which it may come in contact1 especially upon the brass wire-cloth on which the paper is made4 ,the iron is objectionable as it forms a dark red precipitate of oxide of iron4 ,alum as supplied by makers of repute is generally sufficiently pure for even the best classes of paper4 ,many years ago a substitute for alum was introduced1 called ,pochin's aluminous cake4 ,it consisted principally of sulphate of alumina ,al#bc ,,so#d1 and was1 provided it was pure1 as suitable for the papermaker as the more expensive potash alum4 ,it was more economical at equal price1 as it contained about #ad per cent4 of alumina1 whereas potash alum1 even if absolutely pure1 could only contain #ajhe per cent4 ,pochin's aluminous cake however1 was liable to contain a considerable amount of free sulphuric acid and soluble sulphate of iron4 ,of late years1 a number of different varieties of sulphates of alumina have been introduced into commerce1 of so pure a nature1 and at such a low price1 that it is a matter of wonder that they have not entirely superseded the more expensive alum4 ,they are prepared either from very pure native alumina 7bauxite71 or from ,china clay of good quality4 ,methods have been discovered of eliminating almost the whole of the iron and free sulphuric acid4 ,the following analyses of different specimens sufficiently indicate their purity4#ab ,alumina 7,al#b,o#c7 #adhd #adgj #adie #adhe #afjj #afbj ,ferric oxide 7,fe#b,o#c7 #jf #ab #je trace nil trace ,sulphuric acid 7,,so#c7 #cejj #cdfj #cfji #cdid #chjj #chjj ,free sulphuric acid #cb #dj nil #bi nil nil ,lime 7,ca,o7 #aa #aa #ag #ad #af #ad ,water #didb #diie #dhgb #difj #deej #dedc #iige #iihh #iiih #iihb #iiff #iige ,footnote #ab3 ,journ4 ,soc4 ,chem4 ,ind41 ,jan4 #ahhf1 p4 #af4 ,sulphate of alumina possesses this advantage over alum1 that it is more soluble in water1 and thus a stock solution of considerable strength can be prepared4 ,it is soluble in #ada #b parts of cold water1 alum requiring #ah parts for complete solution4 ,the amount of alum or sulphate of alumina added to a pulp is largely in excess of the quantity necessary to precipitate the rosin soap2 as a matter of fact1 in the case of esparto or straw pulps1 for the bleaching of which considerable quantities of bleach have been employed1 and which therefore contain a certain amount of basic lime1 together with calcium chloride1 complete precipitation of the size is effected without the addition of alum4 ,a certain amount is also required to precipitate the starch4 ,the excess of alum appears to be necessary1 however1 not only to brighten the colour of the paper1 but also to render it capable of resisting the action of ink4 ,from experiments made by the authors1 it appears that one part of rosin requires #bi parts of alum for complete precipitation from its solution in soda4 ,one part of starch requires #jdj part alum4 ,colouring4--,cellulose1 except in rare instances1 is never sufficiently white to produce a perfectly white paper1 and the manufacturer finds it necessary to complement the slightly yellow colour which most bleached pulps possess by the addition of small quantities of blue and pink colouring materials4 ,the blues usually employed are ultramarine1 smalts1 and aniline blues2 the pinks are generally preparations of either cochineal or aniline dyes4 ,ultramarine is met with in commerce as a bright blue powder2 the shade of colour and the quality of which vary considerably4 ,in choosing an ultramarine1 attention should be directed not only to its tinctorial power but to its behaviour with a solution of alum1 inferior qualities being entirely discharged by it4 ,all ultramarines are readily decomposed by free acids1 hence the necessity of employing an alum as free as possible from this impurity4 ,smalts on the other hand resists the action of acids1 but it is only used for the finer qualities of paper1 owing to its high price4 ,the aniline blues are perhaps scarcely so brilliant in colour as the above-mentioned colours1 and they #adb are moreover somewhat readily discharged by the action of light2 they have however the advantage of cheapness4 ,the pink colouring matters are sold either as lakes1 that is1 compounds of the colouring matter with alumina or as solutions4 ,they are also frequently to be met with mixed with starch in varying proportions4 ,those made from cochineal are superior to those containing aniline colours4 ,ultramarine can be detected by means of its reaction with hydrochloric acid1 the colour being discharged and sulphuretted hydrogen evolved1 which can be recognised by its odour4 ,smalts is not acted upon by acids4 ,the latter contains cobalt1 the presence of which can be determined by its giving a blue bead with borax in a blowpipe flame4 ,the aniline blues are soluble either in hot water or hot alcohol1 the liquid being intensely coloured4 ,most of them are discharged by treatment either with strong acids or alkalis1 the colour being restored by the reverse treatment4 ,paper of any desired colour may be made either by using rags already dyed the necessary colour or by adding to the bleached pulp in the beater such dyes or pigments as will produce it4 ,any colouring matter which can be obtained in the form of a fine powder or as a solution can be used4 ,blue papers are usually coloured with ultramarine2 the dark blue papers used for wrapping sugar and other purposes are coloured with ,prussian blue1 either added directly to the beater or produced in it by the action of potassium ferrocyanide on ferric sulphate4 ,the so-called toned paper is produced by adding to the pulp a solution of pernitrate of iron1 from which a fine precipitate of oxide of iron is deposited on the fibres2 thus the slightly brown shade characteristic of this kind of paper is produced4 ,the same effect may be produced by the addition of yellow ochre or some similar pigment4 ,the following are a few of the materials which are used for producing coloured papers3--,methyl violet1 eosine1 chrome yellow1 venetian red1 catechu4 ,useful receipts for the preparation of coloured papers will be found in ,dunbar's #8,practical ,paper-,maker4' #adc ,during the time that the loading1 sizing and colouring processes have been going on1 the pulp has been continually acted upon by the roll1 and if these operations have extended over a considerable time1 it is probably in a proper condition for making into paper4 ,the amount of 8beating0 depends1 as has been stated before1 upon the nature of the fibre1 and also to some extent on the nature of the paper for which it is intended4 ,the 8beaterman0 examines the pulp from time to time by taking a portion from the engine and placing it in a hand-bowl containing water3 from its appearance when so diluted he is able to judge of the time during which it may be necessary to continue the disintegration4 ,as soon as this is completed1 the pulp is ready to be let down to the stuff-chests1 usually placed at a lower level than the beaters1 so that the pulp can flow into them by gravity4 ,for this purpose the valve at the bottom of the engine is opened3 to remove the last portion of pulp it is necessary to rinse out the engine with water4 ,,table4--,,strength ,,of ,,alum ,,solutions 7#age ,c41 #fce ,f474 ---------------------------------------- --------------------- ,percentage of ,specific ,gravity4 ,degrees ,twaddle4 ,k#b;,al#b7,,so#d7d #bd ,h#b,o4 ---------------------------------------- --------------------- #aj #ajjfe #acj #bj #ajaaj #bbj #cj #ajaff #ccb #dj #ajbah #dcf #ej #ajbfi #ech #fj #ajcbj #fdj ---------------------------------------- --------------------- #add ,,chapter ,x4 ,,paper ,,machines2 ,,hand-,,made ,,paper4 ,the pulp as it comes from the beaters is now ready to be made into paper4 ,we will first consider briefly the manufacture of hand-made paper4 ,it is made on a mould of wire-cloth1 with a movable frame of wood1 called the 8deckle10 fitting on to the outside of the mould and extending slightly above its surface4 ,the wire-cloth is generally supported by a much coarser wire-cloth1 or by pieces of thick wire1 and these again by wedge-shaped pieces of wood1 the thin end being next to the wire4 ,to form a sheet of paper the workman dips the mould1 with the 8deckle0 in position1 into a vat containing the prepared pulp diluted with water1 lifting up just so much as will make a sheet of the necessary thickness4 ,as soon as the mould is removed from the vat1 the water begins to drain through the wire-cloth1 and to leave the fibres on the surface in the form of a coherent sheet of paper4 ,the felting or intertwining is assisted by lateral motion in every direction given to the frame by the workman4 ,the movable deckle is then removed1 and the mould1 with the sheet of paper1 given to another workman1 called the 8coucher10 who turns it over and presses it against the felt1 by this means transferring the sheet from the wire to the felt4 ,in the meantime the 8vat-man0 is engaged in the formation of another sheet with a second mould4 ,illustration3 ,,the ,,fourdrinier ,,paper ,,machine4 ,,plate ,i4 ,a number of the sheets thus formed are piled together1 alternately with pieces of felt1 and when a sufficient number #ade have been obtained1 the whole is subjected to strong pressure1 to expel the water4 ,the felts are then removed1 and the sheets again pressed4 ,they are then sized1 if required1 by dipping them into a solution of gelatine3 again slightly pressed1 and hung up on lines or poles to dry4 ,such paper is called loft-dried4 ,when dry the sheets of paper are calendered4 7,see ,chapter ,,xi47 ,the making of paper by hand involves considerable dexterity on the part of the workman2 on account of the expensive labour necessary1 in comparison with paper-machines1 it is comparatively little practised in the present day2 certain kinds of paper1 however1 such as bank-notes1 various drawing papers1 and printing papers intended for the production of very elaborate editions are always made in this way4 ,any pattern or name required on the paper is obtained by means of a raised pattern on the wire-cloth mould3 consequently1 less pulp lodges there1 and the paper is proportionally thinner1 thus showing the exact counterpart of the pattern4 ,such devices are known as 8water-marks40 7,see also p4 #aef47 ,the ,paper ,machine4--,the paper machine of the present day1 with all its ingenious improvements1 differs but little in principle from that originally constructed by ,fourdrinier4 ,it consists essentially of an endless mould of wire-cloth1 on to which the prepared pulp flows1 and on which a continuous sheet of paper is formed4 ,the sheet of paper then passes through a series of rollers and over a number of heated cylinders1 where it is completely dried4 ,a modern ,fourdrinier paper machine is shown in plan and side elevation in ,plates ,i4 and ,,ii4 ,the pulp1 after leaving the beaters1 passes into a large vessel called the stuff-chest1 of which there are one or more to each machine4 ,as soon as the beater is empty1 water is run in to thoroughly rinse out the remaining pulp1 the washings also going into the stuff-chests4 ,these may be #adf made either of wood or iron1 and should be provided with arms fixed on a vertical shaft1 made to revolve by suitable gearing4 ,the arms are for the purpose of keeping the pulp thoroughly mixed1 and should only work at a moderate speed1 otherwise they are liable to cause the fibres to form into small knots or lumps4 ,the pulp is drawn from the stuff-chests by means of the pump ,a1 and is discharged into a regulating-box 7not shown74 ,the object of this box is to keep a regular and constant supply of pulp on the machine4 ,it consists of a cylindrical vessel1 having two overflow-pipes near the top1 and a discharge-pipe near the bottom4 ,the pulp is pumped in through a ball-valve in the bottom1 in larger quantity than is actually needed1 the excess flowing away back into the stuff-chests1 through the two overflow-pipes4 ,by this means1 the box is always kept full1 and therefore the stream of pulp issuing out of the bottom pipe is always under the same pressure4 ,it flows from this pipe1 the quantity being regulated by means of a cock1 according to the thickness of paper required1 directly on to the sand-tables4 ,these may be of various sizes and shapes1 but should be so large that the pulp takes some little time to travel over them4 ,they consist of long shallow troughs1 generally of a sinuous form4 ,the bottoms are sometimes covered with woollen felt1 or with thin strips of wood placed across the direction of the flow of the pulp1 and at a slight angle4 ,these serve to retain any particles1 such as sand and dirt1 that may have escaped removal in the previous treatment of the pulp1 and that are heavy enough to have sunk down during the passage of the pulp along the sand-tables4 ,in some mills1 where great care is exercised1 the pulp is caused to flow over sand-tables #bjj yards in length4 ,as the pulp1 when it leaves the stuff-chests1 does not contain sufficient water for the purpose of making paper1 it is mixed1 where it enters the sand-tables1 with a quantity of water from the 8save-all0 7see p4 #aed71 flowing from the box ,b placed at a higher level4 ,in some mills1 instead of being pumped into the #adg regulating-box1 the pulp flows into a small vessel below the stuff-chest1 and is lifted on to the sand-tables by means of buckets fastened on the circumference of a wheel4 ,the pulp1 after leaving the sand-tables1 passes on to the strainers4 ,these consist of strong brass or bronze plates1 having a large number of very fine ,v-shaped slits cut in them1 the narrowest end being on the outside4 ,strainers4--,the strainers are for the purpose of removing from the pulp all lumps formed by the intertwining of the fibres1 and all pieces of unboiled fibre1 which1 if allowed to pass on1 would show in the paper as inequalities in the surface1 or as dark specks4 ,the slits are made narrow at the top1 and gradually increasing in width1 so as to prevent them from getting choked up4 ,these slits allow only the individual fibres to pass through1 and their width varies according to the quality of the paper4 ,they are from #b to #c in4 long1 and they vary in width from #jjg to #je in4 ,they are put at distances of about #a_/d in4 apart4 ,several plates1 each containing about #ejj slits1 are bolted together1 and form a strainer4 ,the whole strainer receives a violent shaking motion1 to assist the passage of the fibres through the slits4 ,in the machine represented1 two of these strainers are shown at ,c4 ,the shaking motion is produced by the ratchet-wheel or cams a acting on the hammer b4 ,an improved form1 called the 8revolving strainer10 has of late years been introduced4 ,the pulp generally passes first through one of these1 and then through the ordinary or 8flat0 strainers1 as they are called4 ,a revolving strainer is shown at ,d4 ,it consists of a rectangular box1 the sides of which are formed of plates perforated with slits4 ,inside this box1 a slight vacuum is formed by means of an indiarubber bellows worked by a crank on the shaft d4 ,the vacuum is intended to serve the purpose of the shake in the ordinary form4 ,the box revolves slowly inside a vat containing the pulp1 and the strained pulp flows into the box ,d#a1 and thence on to the flat strainers4 ,illustration3 ,,fig4 #de4 ,various patents have been taken out from time to time for #adh flat strainers worked by means of a vacuum underneath the plates caused by the motion of discs of indiarubber or thin metal4 ,fig4 #de shows in plan a set of strainers1 as manufactured by ,messrs4 ,g4 ,w4 ,bertram1 similar to those in ,plate ,,ii41 but illustrated somewhat more in detail4 ,the pulp first passes through the flat strainer ,b1 and from thence to the two revolving strainers ,a4 ,from these it flows along the shoots placed at the side on to the paper-machine at ,e4 ,illustration3 ,,fig4 #df4 ,fig4 #df gives a view of a patent flat vacuum strainer made by the same firm1 which may also be used for cleaning straw or esparto previous to its passage over a presse-pte4 ,the pulp flows on to the strainer at a1 and passes away by #adi the cast-iron pipes f4 ,the valve g is for running off waste pulp4 ,the plates are placed at a slope of about #a in4 in their length2 those nearest the supply of pulp are provided with coarser slits1 as the impetus carries the knots forward4 ,the vacuum pumps are worked by the rods d from the shaft e4 ,by means of the tubes c water can be directed on to the plates1 whereby the coarser particles of fibre are carried forward1 and the slits are kept clean4 ,the plates can be removed in a few minutes4 ,figs4 #dg and #dh show in side and end elevation1 ,messrs4 ,masson1 ,scott1 ,bertram's patent self-cleaning strainer4 ,the novelty consists in an arrangement by means of which the upper surface of the plates are continually freed from those portions of the pulp which cannot pass through the slits4 ,the scrapers d are made of vulcanised indiarubber1 and are continually carried forward by an endless chain2 the knots1 c41 collect in a heap at the end of a strainer4 ,the #aej pulp flows on at a1 and passes away through the pipe b4 ,the pumps are driven from the shaft e4 ,illustration3 ,,fig4 #dg4 ,illustration3 ,,fig4 #dh4 ,messrs4 ,c4 ,h4 ,f4 ,l4 ,roeckner's patent strainer 7,no4 #gicb1 #ahhe7 consists of a series of cylindrical tubes1 open at one end and perforated with slits4 ,they are placed in a vat into which the pulp flows4 ,inside the cylinders are placed two1 three1 or more plates1 fixed to the shafts on which the cylinders are supported1 and extending to the circumference4 ,these plates form a kind of fan1 which1 together with the cylinders1 are caused to oscillate by means of a rod and cranks4 ,this oscillating motion serves to draw the fibres through the slits1 and at the same time to keep the outsides of the cylinders clean4 ,the cylinders are easily removable4 ,after a time1 the slits in the plates get too large1 owing to the plate having been worn away by the constant friction of the fibres1 and as they are very expensive1 various attempts have been made to invent plans for partially closing them again4 ,hammering will effect this1 but is liable to break the plates4 ,annandale of ,beltonford has introduced a method of closing the plates1 by means of heavy pressure acting on small steel rollers moving on each side of the slit1 in which is placed a small sheet of metal the exact thickness of the width desired4 #aea ,another method of closing the plates consists in filling them up by means of electrically deposited copper or other metal4 ,they can then be recut in the usual way4 ,in the case of revolving strainers1 all that cannot pass through the slits falls to the bottom of the vat1 in connection with which it is customary to have an auxiliary strainer1 or 8patent knotter10 as it is called1 shown at ,e4 ,all fibre that passes through this one1 which is of the ordinary flat kind with shaking motion1 goes into a box near ,e1 called the 8low box0 for 8save-all0 water 7see p4 #aed74 ,the pulp1 after passing through the strainers1 should be perfectly free from knots and impurities1 and in a fit condition for making paper4 ,in the machine shown1 it passes from the last strainer directly on to the wire1 its flow being regulated by a movable gate e4 ,in some cases1 however1 it first flows into a small vat1 in the centre of which revolves a rod carrying paddles1 with the object of keeping the pulp well stirred up4 ,it is carried right on to the wire by means of the apron1 a piece of canvas1 oil-cloth1 or sheet rubber1 one end of which is fastened to the breast-board e1 the other end resting on1 and covering the wire to the extent of about #ae in4 ,the edges of the apron are rolled up to prevent the pulp from overflowing4 ,after leaving the apron1 it passes under a gate1 or 8slicer10 as it is sometimes called1 made of two pieces of brass1 overlapping each other in the centre1 and bolted together4 ,it is made thus to enable it to be lengthened or shortened according to the width of the paper2 its height from the wire-cloth can be altered by means of screws1 and should be equal at all points1 in order to ensure a uniformly thick sheet of paper4 ,the ends of the two pieces forming the slicer are fastened to the frame f or 8deckle10 as it is called1 and this again is carried by two or more rods stretching right across the wire1 and fastened by small upright supports on both sides to the frame g4 ,the deckle-frame also carries the grooved pulleys h1 along which the deckle-straps i1 endless square bands of indiarubber1 move4 #aeb ,illustration3 ,,fig4 #di4 ,the object of the deckle-straps is to regulate the width of the paper2 they form1 together with the wire-cloth1 a kind of mould into which the pulp flows1 thus corresponding to the mould used in hand-made paper-making4 ,the width of the paper can be altered by shifting the position of the frame f1 and also the deckle-straps1 which are carried on it as described1 the pulleys h being so arranged that they slide along the rods on which they revolve4 ,in order to alter the width of the paper it is necessary to stop the flow of pulp on to the wire1 and it not only consumes a considerable amount of time1 but generally necessitates a partial cleaning up of the machine4 ,various attempts have1 therefore1 been made to devise an arrangement whereby the change can be effected while the paper is being made4 ,several #aec contrivances have lately been introduced1 all similar to the one shown in ,figs4 #di and #ej4 ,in it the frame f carrying the deckle-strap is made to slide along the rods e by means of the small wheel b1 and by a similar arrangement on the opposite side and geared with it4 ,the movable apron l1 ,fig4 #di1 is wound round the spindle g1 and is kept taut by the cords m connected with the springs n4 ,as the deckles approach each other1 the excess of apron is wound up1 when they are separated it unwinds again4 ,the flow of pulp is regulated by two slices a a1 which are kept in position by the screws h4 ,the whole arrangement is securely bolted to the frame of the machine2 c 7,fig4 #ej7 represents the breast-roll1 and corresponds to ,f1 ,plates ,i4 and ,,ii4 ,illustration3 ,,fig4 #ej4 ,the thickness of the paper is regulated by altering the supply of pulp to the wire-cloth1 and by the speed at which the machine is working4 ,this speed may vary from about #fj feet to as high as #bgj feet per minute4 ,the 8wire0 is an endless cloth made of very fine wire1 the fineness depending much on the quality of the paper required4 ,the mesh varies from #fj to #gj and even more threads to the inch4 ,it is not woven endless1 but is joined by very careful sewing with wire4 ,its width varies considerably1 some #aed being made as wide as #abf inches2 the length is generally #ce-dj ft4 ,it is carried by the breast-roll ,f1 the lower couch-roll ,g1 and the small rolls f1 and by a large number of small rolls f4 ,the latter and the breast-roll are supported by the frame g1 while the small rolls f are supported by brackets attached to it4 ,the course of the wire is indicated by the arrows4 ,the frame g works on two pivots g1 and receives a shaking motion from side to side from the rod j1 in connection with a crank worked by two conical drums ,h4 ,the supports g are also pivoted at their lower ends to allow for the shaking motion4 ,this shaking motion is given for the purpose of weaving or intertwining the fibres4 ,one or more of the rolls f can be moved up or down on the support which carries it1 for the purpose of stretching the wire4 ,there is usually a large number of the small rolls f1 as it has been found by experience that1 probably owing to capillary attraction1 they1 cause the water to leave the pulp4 ,though a large quantity of water thus passes through the wire-cloth1 it is necessary to assist it by artificial means4 ,this is done by means of the suction-boxes ,i connected by pipes with the vacuum-pumps ,i4 ,this part of the machine1 which is called the 8wet-end10 is placed at a slight slope of about #a in4 in its entire length1 the lowest end being nearest the strainers4 ,underneath the wire-cloth is placed a box called the 8save-all0 ,k1 connected with the box ,e4 ,the water that passes through the wire-cloth contains a considerable quantity of very fine fibres1 together with size1 alum1 clay1 and colouring materials1 that have passed through the wire1 and which would be lost but for the arrangement now universally adopted4 ,it flows into the box ,e1 and is pumped1 together with the pulp that has passed through the knotter ,e 7see p4 #aea71 into the high box ,b1 whence the mixed stuff flows on the sand-tables1 to be again used to dilute fresh pulp from the stuff-chests4 ,the following numbers will give some idea of the nature and amount of fibre1 c41 which passes through4 #aee ,the paper was made from esparto and straw1 sized with rosin and starch4 ,it contained #ab per cent4 of clay4 ,grains per ,gallon of ,waste ,water4 ,fibre #cdcg ,clay #cgaj ,starch #adj ,illustration3 ,,fig4 #ea4 ,illustration3 ,,fig4 #eb4 ,it is almost impossible to utilise the whole of the back-water passing through the wire-cloth in the way described4 ,in some mills a portion of this water is made to pass through a 8pulp-saver10 such as is shown in ,figs4 #ea and #eb4 ,it consists of a conical drum ,a1 the circumference of which is covered with wire-cloth1 and it is caused to revolve slowly by suitable gearing4 ,the water enters by the pipe ,b1 and passes through the meshes of the wire-cloth1 the pulp gradually finding its way to the wider end1 where it is discharged into the box ,c4 ,it can then be returned to the beaters4 ,this pulp-saver can also be used for recovering the fibre from other waste water1 such as the wash water from the washing and beating-engines2 or it can be used for freeing bleached pulp from water in cases where drainage or hydraulic pressure is not resorted to4 ,if any pattern or name is required on the paper1 it is produced by means of a light skeleton roll1 called a 8dandy-roll10 covered with raised wires in the form of the desired pattern1 #aef placed between the suction-boxes1 and pressing lightly on the still moist paper4 ,the paper is thinned where the wire pattern presses1 and thus a mark 7water-mark7 is produced4 ,the other side of the paper has a mark corresponding to the wire-cloth2 by using a dandy-roll covered with wire-cloth1 the two sides can be obtained alike1 such paper going by the name of 8wove40 ,paper in which a series of parallel lines are produced is called a 8laid0 paper4 ,some water-marks are produced by means of a dandy-roll in which the pattern is formed by depressions in the surface4 ,the paper is thus thicker where the pattern is formed than in the ground-work4 ,de la ,rue 7,patent ,no4 #hcdh1 #ahhd7 has patented the use of dandy-rolls so formed as to produce upon the paper the effects both of thickening and thinning4 ,imitation water-marks can be produced on the finished paper by subjecting it to pressure in contact with plates on which the design has been produced in relief4 ,in this way very beautiful results can be obtained4 7,see ,patent ,no4 #ac1dee1 #ahhd47 ,it sometimes happens that the wire-cloth slips slightly to one side4 ,this can be obviated by the machine-man shifting1 by means of screws1 one of the rolls provided for the purpose with a movable journal1 until its axis is at a slight angle to that of the other rolls4 ,an automatic apparatus has been invented for this purpose4 ,two brass plates are fixed1 one on each side of the wire-cloth1 to a long rod1 connected by suitable machinery with the screws working the movable journal1 so that1 as the wire presses against one or the other of these plates1 the roll is shifted so as to correct this4 ,the paper1 which1 even after passing the suction-boxes1 is still very wet1 passes with the wire-cloth between the couch-rolls ,g ,g4 ,these are hollow copper or brass cylinders1 covered with a tightly-fitting endless jacket of felt4 ,they may also be made of wood 7sycamore or mahogany7 or of iron or iron and brass combined4 ,the pressure of the upper couch-roll upon the lower can be regulated by means of #aeg screws or levers4 ,they serve to press out water from the paper1 and to detach the paper from the wire-cloth4 ,by dexterous manipulation on the part of the machine-men1 the paper is transferred to the endless felt1 travelling over the rolls k in the direction of the arrows4 ,it is known as the 8wet felt10 from the condition of the paper at this stage4 ,in its passage along this felt1 the paper passes between two iron rolls ,k1 called the first press-rolls1 with the object of having the water squeezed or pressed out of it4 ,these rolls are sometimes covered with a thin brass case1 and the top one is provided with an arrangement called the 8doctor10 in order to keep it clean1 and free from pieces of paper that may have stuck to it4 ,the lower press roll is sometimes covered with an indiarubber jacket4 ,the 8doctor0 is a kind of knife placed along the whole length of the roll1 and pressing against it at every point4 ,the pressure on the rolls can be regulated by means of levers1 or1 as in the illustration1 by the screw k4 ,it will be readily seen that the under side of the paper that has been next to the felt will1 in its still moist condition1 have taken to some extent an impression from the felt1 while the upper side will have been made comparatively smooth by the pressure against the top roll of the #ast press4 ,in order to make both sides of the paper as nearly as possible alike1 it is passed through another set of rolls ,l1 called the #bnd press4 ,this time it is reversed1 and enters at the back of the rolls2 thus the other side of the paper is next the metal1 being taken through by the felt 7called the 8#bnd press felt07 travelling on the small rolls l1 the paper1 after leaving the wet felt1 and before being taken on to the #bnd press felt1 travels over the rolls l4 ,the #bnd press felt is necessary1 because the paper is too tender to withstand1 unsupported1 the pressure of the rolls4 ,illustration3 ,,fig4 #ec4 ,the paper1 after passing the #bnd press rolls1 travels over the drying-cylinders ,m1 the number of which varies somewhat4 ,in the machine shown1 there are in all eight cylinders4 ,sometimes as many as twelve are employed4 ,between the #aeh #bnd press rolls and the cylinders1 a passage ,s allows easy access to the other side of the machine4 ,the paper generally passes alone over the first two1 which are only slightly heated2 afterwards it is led over the others by means of felts1 as shown4 ,the arrangements shown at ,r are for the purpose of stretching the felts4 ,the cylinders are heated by means of steam1 and are generally divided into two sets1 between which is a pair of chilled-iron1 highly-polished rolls ,n1 called 8smoothers10 the function of which is sufficiently explained by their name4 ,they are also heated by means of steam4 ,the cylinders are usually made of slightly decreasing diameter1 in order to allow for the shrinking of the paper on drying4 ,messrs4 ,g4 ,w4 ,bertram introduce into some of their machines one or two small drying cylinders1 over which the #bnd press felt travels1 the object being to drive off some of the moisture absorbed from the paper4 ,this contrivance is said to give excellent results1 and to ensure a considerable saving in felts4 ,the arrangement is shown in ,fig4 #ec4 ,it is especially useful in machines running at a high speed1 or in those having limited drying power4 ,after leaving the cylinders1 the paper should be quite dry2 it is then led through the calenders1 of which there are in some machines #aei as many as three sets1 though only one is shown4 ,these are similar to the smoothing-rolls1 just described4 ,pressure is applied by the screws ,o1 or by levers and weights4 ,the friction of the hot calenders on the dry paper develops a large quantity of electricity1 which occasionally discharges itself in bright sparks4 ,it is the practice in some mills to cool the paper before passing it through the calenders4 ,this is effected by passing it over a copper cylinder1 through which a stream of cold water runs4 ,the degree of smoothness or 8finish0 that can be given to the paper by the calenders1 depends to a large extent upon the degree of moisture which it contains4 ,as it leaves the last cylinder it is perfectly dry1 that is to say1 it contains only that amount of water which cellulose1 from whatever source1 always carries4 ,this amount varies slightly with the nature of the cellulose1 and with the plant from which it has been isolated1 and also with the state of the atmosphere1 it being greater on damp days4 ,it would be impossible so to regulate the drying action of the cylinders that the requisite amount of water should always be left in the paper2 it is therefore better to dry it as thoroughly as possible1 and then to add the water1 by artificial means1 just before it passes through the calenders4 ,this method1 moreover1 has the advantage of damping only the surface of the paper4 ,fig4 #ed shows a damping arrangement as manufactured by ,messrs4 ,james ,bertram ,son4 ,the paper on leaving the last drying cylinder passes on to two copper cylinders c1 filled with cold water4 ,steam passes through the pipe a1 and issues through a number of fine holes in a pipe running at right angles to the direction in which the paper is travelling1 and near to it4 ,the steam condenses on the paper and on the surface of the cylinders1 from which the paper absorbs it4 ,the supply can be regulated by the cocks shown in the drawing4 ,the troughs d carry off any excess of condensed water4 ,amongst other methods proposed is one by ,annandale2 it #afj consists in breaking up jets of water into a very fine spray by means of a blast of air4 ,the finished paper1 after passing through the calenders1 is wound on the reels ,p4 ,the gearing by which the whole machine is driven is shown in ,plate ,,ii4 ,illustration3 ,,fig4 #ed4 ,it sometimes happens that1 owing to the increased tension due to the contraction of the paper in drying1 the paper breaks4 ,it is therefore necessary to alter the speed of some of the cylinders to compensate for this4 ,a rough expedient which is largely adopted1 consists in attaching1 by means of a mixture of rosin and tallow1 a piece of felt to one or other of the pulleys 7,plate ,,ii471 and thus altering its speed4 ,tub-sizing4--,the foregoing description is of a machine for the manufacture of engine-sized papers2 some slight modifications are necessary in the case of papers that are tub-sized on the machine4 ,in making the cheaper qualities of tub-sized papers1 the paper1 after being partially dried over a few cylinders1 is passed through a vessel containing a #afa solution of gelatine 7see p4 #afb74 ,it then goes between a pair of rollers1 which press out the excess of size1 and then again over drying-cylinders4 ,the vessel or trough containing the size is filled to overflowing from a tank placed at a higher level2 the overflow passes into a lower vessel1 from which it is pumped up to the top tank4 ,the size is kept warm by means of a coil through which steam passes placed in one or other of the vessels containing it4 ,the paper passes between a pair of rollers placed in a trough and dipping into the size4 ,the size may be made to flow through a pipe pierced with a number of holes1 the stream running directly on to the web of paper4 ,in the other1 and perhaps most general way1 at least for the better qualities1 the paper is wound off immediately after leaving the last drying-cylinder ,a 7,fig4 #ee71 and sized at some future time1 or it may be passed directly into the vat ,b containing the size4 ,after passing between the squeezing-rolls4 ,c1 it is generally wound off as at ,d2 and after having stood some time #afb to allow the size to be evenly absorbed by the paper1 it is wound off from ,f1 and passed over the cylinders ,h1 of which there may be a very great number1 some machines having over #cjj of them4 ,these cylinders are made of light spars of wood2 inside them1 and revolving rapidly in an opposite direction1 are the fans ,g4 ,the paper1 in travelling over these drums1 is only slowly dried1 and is supposed by this means to be more perfectly sized1 and increased in strength4 ,it is wound on to reels again at ,i4 ,only the first and last two drums are shown4 ,this method was devised to imitate1 as far as possible1 the sizing process of hand-made paper4 ,even now1 paper that has been made on the machine is sized by hand1 after having been cut into sheets1 much in the same way as hand-made4 ,illustration3 ,,the ,,fourdrinier ,,paper ,,machine4 ,,plate ,,ii4 ,illustration3 ,fig4 #ee4 ,preparation of ,size4--,very pure gelatine can now be obtained in the form of light-coloured cakes4 ,it is1 however1 more economical for the paper-maker to prepare his own3 this is therefore done in the majority of cases4 ,a great many animal substances1 such as clippings of hides1 horns1 bones1 c41 yield gelatine when heated with water4 ,any of these substances may be used1 the first being the chief raw material4 ,they are first softened by soaking in cold water for some days3 they are then cleansed by washing in a stream of water4 ,the next operation is that of heating with water4 ,this is usually done in iron or copper vessels provided with a false bottom or outer jacket1 into which steam may be passed4 ,the hide cuttings are covered with water1 and the mass gradually raised to a temperature of about #he 7#ahe ,f474 ,in from #aj to #ae hours nearly the whole of the cuttings will have passed into solution as gelatine4 ,this solution is then drawn off and any insoluble substance suspended in it is removed by subsidence or filtration4 ,the hides contain a certain quantity of fat1 which collects on the surface of the solution4 ,the residue in the boiler is again heated with water and the solution added to the bulk4 ,it is of the greatest importance that too high a temperature be avoided1 as gelatine is liable1 when strongly heated with water1 to lose its power of gelatinising4 #afc ,to the filtered solution of gelatine1 which should be1 if properly prepared1 of a pale colour1 a quantity of alum solution is added4 ,the effect of alum upon gelatine is very remarkable4 ,if added slowly it will be found gradually to render it stiff until at a certain point the mass will become almost solid2 a further addition renders it fluid again4 ,it is in this state ready to be used for sizing purposes4 ,the amount of alum necessary to produce this effect is about #bj per cent4 of the weight of the raw material4 ,the alum is also useful in preventing the decomposition of the gelatine1 but its chief characteristic is to render the gelatine a more efficient sizing material4 ,there is no doubt that1 besides its action upon the gelatine itself1 it has a considerable effect upon cellulose4 ,it is of the greatest importance that the alum or the sulphate of alumina1 which can be substituted1 should not contain any free acid4 ,this is especially necessary in the case of papers made from rags1 in the bleaching of which an acid has been used2 one effect of which is to remove all basic substances derived from the boiling or bleaching processes4 ,in the case of esparto and similar fibres1 a considerable quantity of such substances are present in the pulp1 the result being that the free acid of alum is to a large extent neutralised1 and its injurious effects prevented4 ,the effect of the free acid is seen in the weakening of the paper and the destruction of metal surfaces with which it comes in contact4 ,the effect of acid upon cellulose will be found more fully described in p4 #ab4 ,many paper-makers add to the gelatine a certain quantity of soap1 the effect of which is to render the paper capable of taking a high finish4 ,the soaps employed should be white and firm1 and should be free from rosin4 ,some soap-makers prepare a special soap for paper-making4 ,they are usually made from tallow1 or a mixture of this with a small quantity of coconut oil4 ,if a solution of soap be added to one of alum1 a double decomposition immediately occurs1 the fatty acid being thrown down in combination with the alumina1 and the soda #afd combining with the sulphuric acid4 ,if1 however1 the soap solution be previously mixed with a solution of gelatine1 no precipitation takes place1 the mixture forming an emulsion having somewhat the appearance of thin milk4 ,various attempts have from time to time been made to size paper in the engine with gelatine1 by precipitating it in the pulp after the manner of rosin sizing1 but as yet no successful method has been devised4 ,single-cylinder ,machines4--,modified forms of the original ,fourdrinier machine have been introduced to meet various requirements4 ,one suitable for the manufacture of very thin paper1 or of papers one side only of which is required to be glazed1 called a single-cylinder or ,yankee machine1 is shown in ,fig4 #ef4 ,illustration3 ,,fig4 #ef4 ,it resembles the ,fourdrinier machine as far as the couch-rolls ,a and ,b4 ,the paper is taken off the wire-cloth on to an endless felt running round the upper couch-roll ,a1 and travelling in the direction of the arrows4 ,it is taken from the felt on to the large drying-cylinder ,c1 of about #aj feet diameter1 heated with steam4 ,it is carefully turned and polished so as to impart a high gloss to the surface of the paper with which it is in contact4 ,calender-rolls are sometimes supplied in addition4 ,the arrangement shown at ,d is for the purpose of washing the felt4 ,this is necessary to cool and open it out after passing between the cold press-roll ,e and the hot cylinder4 #afe ,the paper1 after passing over the greater part of the surface of the cylinder1 is sufficiently dried1 and it is then wound off at ,f4 ,illustration3 ,,fig4 #eg4 ,a machine of a very different construction from the ordinary form is shown in ,fig4 #eg4 ,the pulp1 after passing through the strainer ,a1 enters the vat ,b1 in the centre of which a large drum or cylinder ,c revolves4 ,this cylinder is covered with fine wire-cloth1 and on it the paper is made4 ,as it revolves1 the fibres attach themselves to the wire1 and the water passes through the meshes1 being assisted by means of a pump4 ,the sheet of paper thus formed is taken on to the endless felt passing round the couch-roll ,d1 and travels along with it to the large drying-cylinder ,e1 heated by steam4 ,it leaves the felt at ,f1 and is then taken on to the cylinder1 after travelling round which it is sufficiently dried1 and is then wound off as at ,g4 ,the felt on its return journey passes through the washer ,h1 where it is cleaned and freed from adhering particles by the scraper ,i4 ,it is squeezed free from excess of #aff water by the rolls ,k4 ,paper made on such a machine is weaker than that made in the ordinary way1 because it has not been found possible to give a shaking motion to the cylinder1 and thus the fibres are only imperfectly felted4 ,a modification of this machine is used for making millboards1 the difference being that it has no drying-cylinder4 ,the felt carrying the paper passes between a pair of press-rolls1 which squeeze out the water4 ,the sheet of paper is then allowed to wind round the top press-roll until of the required thickness4 ,when this happens1 it is cut off the roll by a knife4 ,the thick sheets so produced are dried either in the open air or in a room heated for the purpose4 7,see p4 #ajh1 ,fig4 #ca47 #afg ,,chapter ,,xi4 ,,calendering1 ,,cutting1 ,,etc4 ,the paper1 as it leaves the machine1 is for many purposes not sufficiently highly glazed1 and it is therefore necessary for it to undergo a further process of calendering4 ,this may be done in various ways4 ,illustration3 ,,fig4 #eh4 ,one method1 called 8web glazing10 is to pass the paper between a number of rolls1 alternately of polished iron and very highly compressed paper or cotton4 ,the construction of such a calender will be understood by reference to ,figs4 #eh 7end elevation7 and #ei 7front elevation74 ,the reel of paper1 as taken from the machine1 is shown at ,a 7,fig4 #eh71 its course over the rolls being indicated by arrows4 ,after passing over the bottom roll1 it is wound off on a wooden or hollow iron cylinder ,b 7,fig4 #eh71 driven by the toothed wheel shown by the dotted line ,c1 on the same shaft as the wheel ,d1 which is driven by ,e1 keyed upon the bottom roll4 ,the whole machinery is driven by the large toothed wheel ,f 7,figs4 #eh and #ei71 which is itself driven by the small wheel ,g on the main shaft ,h4 ,the paper rolls are marked ,p1 and the iron rolls ,i4 ,it will be seen that there are two paper rolls in the middle1 for the purpose of1 as it were1 reversing the paper1 and so making both sides alike4 ,pressure is applied to the rolls by means of the screws ,k1 and by the weight ,l 7,fig4 #eh7 acting on the compound lever ,m4 ,the brake1 which consists of a strap of leather1 pressing1 by means of the weight and lever ,n1 on the circumference of the wheel ,o1 connected by toothed wheels with the cylinder ,a on which the paper is wound1 is used for the purpose of preventing the paper from leaving #afh the cylinder too rapidly4 ,but for this appliance1 the paper would be apt to crease4 ,the paper rolls have an inner core of iron1 the paper only extending to a depth of about #e in4 ,the iron rolls are hollow1 and are connected with steam-pipes1 by which they can be heated4 #afi ,illustration3 ,,fig4 #ei4 ,another method1 known as 8friction-glazing10 employed for giving a very high finish to paper1 generally on one side only1 is to pass it between a large paper roll and a smaller iron one1 the latter revolving at a much greater speed than the #agj former4 ,by this means a very smooth surface can be obtained4 ,it is sometimes assisted by rubbing a small quantity of bees'-wax on the small iron roll4 ,the above-mentioned methods apply to the glazing of paper in the web4 ,paper cut into sheets may also be treated in the same way4 ,various modifications of these calenders have been devised2 they do not1 however1 involve the application of any special principle4 ,plate-glazing1 a method that is adapted to hand-made and the better qualities of paper1 consists in applying heavy pressure to sheets placed between polished plates of copper or zinc4 ,the metallic plates and the sheets of paper are made into bundles1 and the whole is passed between two strong rolls1 heavy pressure being communicated to them by means of screws or levers and weights applied to the ends of the upper roll4 ,illustration3 ,,fig4 #fj4 ,a calender for this purpose is shown in ,fig4 #fj4 ,the bundle of plates and paper is passed along the table a2 after #aga passing through the rolls c1 it slides along the inclined table d1 where it is received by a workman4 ,the pressure on the rolls is regulated by the handle e and the weights b4 ,by passing paper between rolls on which devices have been cut1 the 8repped0 and other similar papers are produced4 ,with calender rolls of the ordinary construction1 as the pressure is applied at the extreme ends1 the roll is liable to assume a slightly curved shape1 the effect of which is to produce an uneven surface on the paper1 the outer portion of the web being more highly finished than the centre4 ,illustration3 ,,fig4 #fa4 ,this defect is obviated to a very large extent by ,schurmann's ,patent ,anti-,deflection ,rolls 7,fig4 #fa74 ,the roll proper consists of an outer shell a1 through the centre of which and securely wedged in at b is the centre core c1 the ends of which run in journals1 and to which pressure is applied in the usual way4 ,the pressure is communicated to the outer shell at the point of contact b1 the result being that the parallelism of the surfaces of the rolls is maintained1 and in consequence1 the paper tends to be equally finished in every direction4 ,cutting4--,except for special purposes1 such1 for example1 as for use in a continuous printing machine1 paper is usually sent from the mill in the form of sheets4 ,the form of cutter1 called a revolving cutter1 generally used1 is shown in ,fig4 #fb4 ,the paper from the webs ,a is drawn forward by the rolls ,b2 it is then ripped into widths of a convenient size by means of two circular knives1 the upper one of which is shown at ,c4 ,it again passes between a pair of rollers1 after leaving which it meets a knife ,d fastened to the revolving drum ,e1 and pressing against a fixed knife not shown4 ,the cut sheets #agb then fall upon the endless travelling felt ,f4 ,the action of the knives will be understood by reference to ,fig4 #fc4 ,the edges of the two knives are shown at ,a and ,b4 ,the knife ,b has a slot1 in which the bolt ,d slides1 and it is kept in position by means of a spring4 ,this spring causes the knife to slide back slightly as it comes against the fixed knife ,a4 ,the position of the paper is shown by the dotted line ,c4 ,the knife ,b is set on the drum not quite horizontally1 so that one end meets the stationary knife a little before the other1 thus acting in every respect like a pair of scissors4 ,fig4 #fd shows a pair of ripping-knives4 ,the upper one ,a is kept in position against the lower one ,b by means of the spring ,c4 ,the cutting surfaces are slightly hollowed out1 so as to have a sharper edge4 ,the paper is shown by the dotted line ,d4 ,by altering the relative speed of the drum ,e #agc and the rolls ,b1 by means of the expanding pulley ,g1 sheets of any desired size can be cut4 ,the cutting-knives are sometimes placed inclined to the drawing-in rolls ,b1 so that the sheet1 instead of being cut into a rectangle1 is cut into a rhomboid4 ,such paper is used chiefly for the manufacture of envelopes1 this shape occasioning a smaller loss when the envelopes are cut out4 ,illustration3 ,,fig4 #fb4 ,illustration3 ,,fig4 #fc4 ,illustration3 ,,fig4 #fd4 ,single-sheet ,cutter4--,it is sometimes necessary1 as in the case of paper having a water-mark1 that the sheet should be cut with great exactness1 so that the device shall come exactly in the centre4 ,the ordinary cutter cannot be relied on for this purpose1 and1 in its place1 a machine called a 8single-sheet cutter0 is used 7,fig4 #fe74 ,it consists essentially of a large wooden drum ,a1 fixed on a horizontal axis1 over which the paper is led by a pair of drawing-in rolls ,b4 ,the paper is held against the drum by a clamp worked by the arm ,c4 ,the paper is cut by the knife ,e moving against the stationary knife ,d4 ,after the cut1 the drum describes part of a circle1 the paper being still held1 so that it cannot go back with the drum4 ,as soon as it has gone far enough1 the clamp is removed1 and the drum returns1 bringing the paper with it4 ,the length of the arc through which the drum moves1 and therefore the size of sheet1 is regulated by the length of the crank-arm ,f4 ,if from any cause the cut should not take #agd place at the right time1 the man in charge can1 by pressing against the clamp1 retard the motion of the paper1 and thus bring back the cut to the right place4 ,the small roller ,g is for the purpose of keeping the paper always tight4 ,illustration3 ,,fig4 #fe4 ,guillotine ,cutter4--,it is sometimes necessary to trim the edges of sheets of paper or to divide them into smaller sheets4 ,this is done by means of a guillotine cutter1 an improved form of which1 as manufactured by ,salmon of ,manchester1 and called the 8,victory0 cutter1 is shown in ,fig4 #ff4 ,the paper to be cut is placed on the table ,f1 touching the back gauge ,g1 which can be brought backwards or forwards by means of the handle ,h1 thus regulating the size of sheet4 ,the machine is set in motion by means of the lever ,a1 which acts upon a friction-clutch connected with the driving-gear4 ,this causes the knife-bar ,b and the clamp ,c to descend4 #age ,when the latter meets the paper its progress is arrested4 ,the knife ,d1 however1 continues to descend1 and passes through the sheets of paper4 ,by means of slots placed at the back1 the knife is made to take a diagonal course4 ,the pressure of the clamp is maintained upon the paper during the cutting operation by means of a powerful spring contained in the tube ,e4 ,illustration3 ,,fig4 #ff4 ,sorting4--,the sheets of paper are now ready to be examined before being finally sent away from the mill4 ,this is done in the 8,finishing-house10 or 8,salle0 as it is sometimes called4 ,this sorting is usually performed by women1 who reject the inferior or damaged sheets4 ,these are sold at a reduced price under the name of 8retree40 ,paper is sold in sheets of definite sizes1 and is made up into reams containing from #dhj to #eaf sheets4 ,these sizes #agf correspond to different trade names--such1 for example1 as crown1 demy1 royal1 imperial1 c4 ,the weight per ream is usually expressed in addition to the name1 thus3 #ad-lb4 demy1 #ah-lb4 double crown1 c4 ,in this way the consumer is enabled to make a rough comparison of the thickness of the different kinds of paper4 ,in making paper it is the duty of the machineman to examine and weigh from time to time a sheet of the desired size1 in order to ensure uniformity4 ,special lever balances can be obtained1 showing at a glance the weight per ream of different numbers of sheets4 #agg ,,chapter ,,xii4 ,,caustic ,,soda1 ,,recovered ,,soda1 ,,etc4 ,as we have already pointed out1 caustic soda and lime are the only alkalis employed by the paper-maker for boiling fibres2 the special cases in which carbonate of soda is used have been mentioned in their proper place4 ,the preparation of milk of lime requires little or no description1 as the operation is a simple and tolerably familiar one4 ,before using1 it should be passed through a fine wire sieve1 to keep back sand1 coal1 and similar impurities which the lime invariably contains4 ,caustic soda is met with in commerce in four forms1 differing from each other in alkaline strength and colour1 and of course in price4 ,the lowest quality is what is known as caustic 8bottoms03 it consists of that portion remaining at the bottom of the caustic-pot after the clear fused caustic soda has been ladled out1 and it contains a considerable quantity of ferric oxide and other insoluble impurities4 ,it is of a dark reddish brown colour1 and contains #ej-fj per cent4 of alkali 7,na#b,o74 ,its use in paper-making cannot be recommended1 except for the preparation of the very lowest grade of pulp4 ,the solution should be allowed to remain at rest1 in order that the insoluble matter may subside4 ,the next in quality is known as cream caustic1 so called from its slightly brown colour4 ,it is usually sold containing #fj per cent4 of alkali1 in the form of a tolerably friable mass1 having a crystalline structure4 ,it is a very suitable form of alkali for the paper-maker4 ,the next in order is what is called #fj per cent4 white4 ,it #agh consists of a hard white mass1 requiring considerable force to break it4 ,though whiter in appearance than cream caustic1 it is in reality less pure1 as it contains a considerable quantity of salt4 ,it is made by continuing the evaporation of the caustic liquor to a further point than is the case with cream caustic1 the result being that the whole of the water is driven off4 ,a small quantity of nitre is then added to oxidise the sulphides and other compounds which impart the colour to cream caustic4 ,common salt is then added to reduce its strength to #fj per cent41 in order to satisfy the whim of the consumer1 who insists upon an article of a given definite strength4 ,on this account it is somewhat inferior to cream caustic1 and is1 moreover1 more expensive4 ,the highest quality of all is white #gj per cent4 ,this resembles white #fj per cent4 in appearance1 but is much purer1 and more expensive4 ,a very pure form of caustic soda has within the last few years been introduced by the ,greenbank ,alkali ,company4 ,it consists of small fragments1 more or less crystalline1 of almost pure sodium hydrate4 ,it can be packed in wooden casks1 and it dissolves very readily in water4 ,it contains #gf per cent4 of alkali4 ,it is1 however1 much too costly for boiling purposes2 it might1 however1 be used for the preparation of rosin size4 ,the following analyses of different forms of caustic soda and their relative prices will possibly be of interest3-- ---------------------------------------- -------------------------- 7,davis47 7,davis47 7,morrison47 ,white 7#gj ,per ,white 7#fj ,per ,cream 7#fj ,per ,cent4 ,na#b,o74 ,cent4 ,na#b,o74 ,cent4 ,na#b,o74 ---------------------------------------- -------------------------- ,sodium hydrate #hifj #gebe #gjjj ,sodium carbonate #bdh #bec #ejj ,sodium chloride #cib #agdj #gjj ,sodium sulphate #cdb #ddj #bjj ,sodium sulphide #jjb #jjc -- ,sodium silicate #jcj #jcj -- ,sodium aluminate trace trace -- ,water none none #aehj ,insoluble matter none none #jbj ---------------------------------------- -------------------------- #agi ,their relative prices per ton f4o4b ,liverpool1 in ,december #ahhf1 were3--#gj per cent4 white1 #hl4 #es42 #fj per cent4 white1 #gl4 #es42 #fj per cent4 cream1 #gl4 ,all the above-mentioned forms of caustic soda occur in the form of more or less hard masses1 and are contained in thin wrought-iron drums1 which are filled with the caustic in a fused state4 ,the soda is removed by breaking the drum with a chisel and hammer4 ,the lumps of caustic may be put direct into the boiler1 though it is better to dissolve them previously in water and allow any insoluble impurities to settle to the bottom of the solution4 ,instead of buying caustic soda direct1 it is the custom of some paper-makers to prepare it for themselves from carbonate of soda1 which can now be obtained in various forms1 some of great purity4 ,it occurs as caustic ash1 containing about #dj per cent4 of alkali as carbonate1 and about #aj per cent4 as caustic soda2 soda-ash containing about #eb per cent4 total alkali1 nearly all as carbonate2 and refined soda-ash containing #eg-eh per cent4 of alkali as carbonate4 ,some forms of carbonate of soda1 such1 for example1 as those made by the ammonia process1 are of even greater purity4 ,the method of converting sodium carbonate into caustic soda will be described subsequently4 ,unless the arrangements for washing and draining the lime-mud are very perfect1 it is probably cheaper for the paper-maker to buy his caustic direct from the maker4 ,soda ,recovery4--,in former years1 the liquors in which rags1 esparto1 and other paper material had been boiled1 was run into the nearest watercourse2 but now1 owing partly to the fact that is insisted upon by the ,rivers ,pollution ,act of #ahgf1 and partly because it can be made remunerative1 all these liquors are preserved1 and the soda they contain utilised4 ,the method adopted is to evaporate to dryness and ignite the residue4 ,the soda during the process of boiling takes up a large amount of non-cellulose fibre constituents and dissolves them as resinous compounds4 ,these on evaporation and ignition become converted into sodium carbonate4 ,many raw #ahj materials1 especially esparto and straw1 contain a large amount of silica1 a large proportion of which is dissolved by the soda in the form of sodium silicate1 in which form also it is found in the recovered soda4 ,illustration3 ,,fig4 #fg4 ,illustration3 ,,fig4 #fh4 ,the apparatus for accomplishing the evaporation varies with almost every mill4 ,in some1 it is very primitive and #aha crude1 consisting perhaps of only a furnace for incinerating the residue1 and over it a pan containing the liquor1 the latter being heated and evaporated by the heat from the furnace4 ,it is obvious that1 with such an arrangement1 a large quantity of heat must be wasted4 ,to economise as much as possible of this waste heat1 various plans have been suggested4 ,that of ,rckner1 of ,newcastle1 appears to be to a great extent efficacious4 ,it consists practically of a series of shallow trays ,b 7,fig4 #fg7 placed in a brick chamber1 alternated so as to allow the heated air from the furnace below to play upon the surface of each in succession1 on its way to the chimney1 with which the whole system is in connection4 ,above the chamber containing these trays1 is a large tank ,c1 containing a store of the liquor to be evaporated1 placed there so as still further to economise the heat1 and from which the liquor runs on to the trays4 ,the furnace ,a is of the ordinary reverberatory kind2 below it1 and connected with it by a kind of damper1 is a large chamber ,j1 where the calcined residue from the furnace is put to cool1 thus preventing any nuisance from the smell of the burning mass4 ,the chamber is provided with a pipe ,l1 through which the vapours pass into the furnace4 ,several pipes ,e from the furnace pass through the #ahb tank1 to assist in warming the liquor4 ,the residue1 when cold1 is drawn through doors from the chamber below the furnace4 ,rckner has devised an apparatus 7,fig4 #fh71 consisting of a small chamber containing a series of pipes ,a1 through which a stream of cold water constantly runs1 in connection with the flue from his evaporator1 for the purpose of condensing volatile bodies1 and thus preventing1 to a certain extent1 contamination of the surrounding air4 ,a very economical form of evaporator is that invented by ,porion1 a ,french distiller1 and named after him4 ,it is shown in sectional elevation and plan in ,figs4 #fi and #gj4 ,it is largely used on the ,continent1 and also in ,england and ,scotland4 ,it consists of a large chamber k1 the floor of which is slightly inclined from the chimney shaft1 and through which the waste heat from the furnace a passes4 ,illustration3 ,,fig4 #fi4 ,illustration3 ,,fig4 #gj4 ,the liquor to be evaporated is run in at the end nearest the chimney from the tank placed above the chamber c4 ,a number of cast-iron fanners i1 dip into the liquor and revolve rapidly1 usually at the rate of about #cjj revolutions per #ahc minute1 producing and filling the chamber with a very fine spray1 thus presenting a very large evaporating surface4 ,between the furnace and the evaporator are placed the chambers c and f4 ,in c a number of brick walls d are so placed that the flames from the furnace are intercepted and broken up4 ,the object of this is to give time for all the products of combustion to be thoroughly burnt up1 which would not be the case without the 8smell-consumer10 as these chambers are called4 ,this part is an addition to the original evaporator1 and was devised by ,messrs4 ,menzies and ,davis4 ,the liquor after having been concentrated in the chamber k runs into a trough placed alongside the doors h and flows into one or other of the furnace beds b where it is still further concentrated1 and the residue ignited by the flames from the fires a4 ,the draught can be regulated by the damper g1 and also by one placed near the shaft j4 ,the doors e1 in the smell-consuming chamber1 are for the purpose of cleaning out4 ,the fanners i are worked by a small steam engine1 not shown in the drawing4 ,under properly regulated conditions very excellent results can be obtained with this evaporator4 ,the temperature of the gases near the chimney should not be higher than about #he4 ,by running the fanners at a very high speed the temperature of the gases may be even further reduced1 thus showing the completeness of the evaporation4 ,this form of evaporator is open to the objection that the whole of the sulphur in the coal employed for the furnaces1 finds its way into the recovered soda4 ,it combines with the alkali to form sulphite of soda1 part of which is decomposed in the furnace with formation of sodium sulphate1 sulphide1 and other sulphur compounds4 ,the same objection1 of course1 applies1 though perhaps in a less degree1 to all systems of evaporation in which the flame is in contact with the liquor to be evaporated4 ,the ,porion evaporator can be erected at very small cost1 and costs but little for maintenance4 ,it is capable of producing #c_/d ton of recovered soda per ton of coal with liquors #ahd of the usual strength4 ,it has proved itself to be perhaps the most economical evaporator existing4 ,some time ago there was erected in ,lancashire an evaporator invented and patented by ,mr4 ,alfred ,chapman4 ,it is shown in ,figs4 #ga1 #gb1 #gc1 and #gd4 ,the evaporation is effected at a low temperature in three vacuum pans ,e1 and with the unusual result that the concentrated liquor gelatinises after leaving the third vacuum-pan1 instead of taking the ordinary form of the concentrated products of other evaporators4 ,it is said that this apparatus gives an excellent product1 with great economy of labour and water1 and with no drainage of foul liquor from the buildings4 ,observations extending over three months have proved that it evaporates #bb lb4 of water from the liquor per lb4 of coal used under the boiler4 ,it is however very costly to erect4 ,illustration3 ,,fig4 #ga4 ,illustration3 ,,fig4 #gb4 ,illustration3 ,,fig4 #gc4 ,illustration3 ,,fig4 #gd4 ,the waste liquor is discharged into the tank ,a1 whence it is pumped by the donkey-engine ,b1 through the feed-heater ,c1 #ahe into the boiler ,d1 which receives heat from the incinerating furnace ,h1 and1 in case of need1 from an auxiliary furnace shown on the plan1 under the feed-liquor-heater4 ,the steam produced in ,d is taken to the first vacuum-pan at ,e1 and having heated its contents1 the products of evaporation pass over into the tubes of the second pan2 this1 in its turn1 gives up its products of evaporation to the third1 whence they go to the condenser of the vacuum-engine ,f4 ,thus the heat from the furnace ,h is used for incinerating the concentrated liquor #ahf on its bed1 for beating the feed-liquor in the feed-heater pipes1 and for making steam out of the liquor itself in the boiler2 this steam finally drives the donkey-pump and vacuum-engine1 and causes the evaporation in the three vacuum-pans ,e4 ,one advantage of this evaporator is the fact that the liquor is evaporated out of contact with the furnace gases4 ,whatever be the method of evaporating or concentrating the liquor1 the final treatment in the furnaces is much the same in every case4 ,the furnaces shown in ,figs4 #fi and #gj may be taken to represent the ordinary form4 ,the concentrated liquor is run on to either of the beds b1 where the last portions of water are driven off by the heat from the fireplaces a1 and the residual mass is ignited until all the organic matter contained in the liquors is carbonised and the soda is converted into carbonate of soda4 ,this takes place in about #d hours1 according to the degree of concentration of the liquor as it is run into the furnaces4 ,the running in of liquor should be done with great care1 as explosions sometimes occur through the sudden liberation of steam on the liquor coming in contact with the hot beds4 ,the charge should be allowed to remain in the furnace until it is thoroughly carbonised and all volatile matters have been driven off1 otherwise a nuisance may be caused when the still burning mass is exposed to the air4 ,rckner's evaporator is provided with a special chamber into which the charge is drawn 7,j1 ,fig4 #fg74 ,the composition of the recovered soda varies with the nature of the liquors from which it has been obtained1 and1 as has been already pointed out1 with the form of evaporator employed4 ,it consists essentially of carbonate of soda1 together with a certain amount of silicate of soda1 if derived from liquors in which straw or esparto have been boiled1 chloride of sodium1 sulphate of soda1 sulphite of soda1 sulphide of sodium1 and other sulphur compounds1 the rest being made up of carbon and insoluble impurities4 ,the amount of soda varies from #ce to #de per cent4 7,na#b,o74 ,the following analysis #ahg will give some idea of the composition of ,recovered ,soda3-- #ac,sodium carbonate #gbcc ,sodium hydrate #aic ,sodium chloride #hcj ,sodium sulphate #cie ,sodium sulphite #fc ,silica #gji ,carbon #dgj ,oxide of iron and alumina #ej ,other constituents 7by difference7 #eg #ajjjj ,the whole of the soda present as sulphur compounds is not lost1 as a large proportion of it is present as sodium sulphite1 most of which is converted into caustic soda by the causticising process4 ,footnote #ac3 ,a certain quantity of potash derived from the mineral constituents of esparto and straw is always present in recovered soda4 ,a certain amount of soda is carried forward1 partly mechanically and partly volatilised1 to the flue leading to the chimney4 ,this accumulates1 and may be from time to time removed in the form of fine dust4 ,it contains1 besides carbonate of soda1 much sulphate and chloride4 ,in two different samples examined by the authors1 the amounts of soda 7,na#b,o7 present were #bej and #bga per cent4 ,causticising4--,the next process consists in converting the sodium carbonate in the recovered soda into caustic soda4 ,this operation is known as 8causticising10 and consists in heating a solution of the soda with lime4 ,the decomposition which takes place is shown in the following equation3-- ,sodium ,lime4 ,water4 ,caustic ,calcium ,carbonate4 ,soda4 ,carbonate4 ,na#b;,,co#c ,ca,o ,h#b,o #b ,na,o,h ,ca,c,o#c4 ,the recovered soda should be dissolved in separate vessels4 ,perhaps the best form of apparatus is a series of lixiviating tanks such as are used for dissolving the alkali in black ash4 #ahh ,by this means a nearly perfect exhaustion of the mass can be effected with a minimum of labour4 ,special tanks are sometimes made for the purpose1 provided with mechanical stirrers4 ,it is essential in dissolving the recovered soda that a high temperature should be employed1 as otherwise a portion of the soda present as silicate of soda will be lost1 as it is only with difficulty soluble1 and requires rather prolonged heating with water4 ,whatever the form of apparatus employed it should be so arranged that1 after running off the strong liquor1 the insoluble residue may be further treated with water4 ,in the case of the vats mentioned above1 this process is made continuous1 pure water being run in at one end1 and strong liquor flowing from the other4 ,if other forms are used1 the liquor after settling1 may be run off by means of a pipe passing through the bottom or side of the vessel1 and near the bottom1 and consisting of two parts1 one long1 and one short4 ,the short part is stationary1 and is connected to the longer part by means of a movable knee joint1 allowing it to be deflected4 ,the liquor having settled sufficiently1 the movable limb is lowered beneath the surface of the liquor which is then allowed to flow through4 ,as the surface of the liquor falls1 the pipe is gradually lowered4 ,in this way the clear solution can be run off without disturbing the residue at the bottom4 ,the open end of the pipe is usually covered with coarse wire gauze1 to keep back insoluble impurities4 ,with properly calcined recovered soda1 the solution should be bright and almost colourless4 ,if at all brown in colour1 and if it has an empyreumatic odour1 it indicates imperfect calcination4 ,the residue in the dissolving tanks consists chiefly of carbonaceous matter1 together with some soda1 insoluble matter1 c4 ,the liquor is now ready to be causticised4 ,this should be done in a separate vessel1 although it is the practice in many mills to perform this operation in the same vessel in which the solution of the soda has been conducted4 ,a good form of causticiser can be made from an old egg-shaped boiler1 by cutting it in two along its length4 #ahi ,it should be provided with two or more vertical steam pipes1 connected at the bottom of the boiler with a horizontal pipe perforated with numerous holes4 ,the vertical steam pipes should be furnished with injectors1 whereby air is drawn in1 and forced with the steam through the holes in the horizontal pipe4 ,the stream of air serves the double purpose of thoroughly agitating the liquor and of oxidising any sodium sulphide in the recovered soda4 ,the liquor before causticising should be reduced in strength to about #bj-be degrees ,twaddle1 which may be done with the washings of the residue from the recovered soda1 or from the washings obtained subsequently from the lime-mud4 ,this strength should never be exceeded1 otherwise imperfect conversion into caustic soda is the result4 ,this is due to the fact that concentrated solutions of caustic soda react upon calcium carbonate1 forming sodium carbonate1 and calcium hydrate1 the reaction being the reverse of that indicated in the above equation4 ,if the liquors are very strong in carbonate of soda1 and comparatively free from sulphate1 they should not be causticised at much over #bj ,twaddle1 if they contain much sulphate1 and therefore less carbonate1 the higher strength can with safety be adopted4 ,the causticising vessel should be provided with a stout iron cage or basket1 into which the lime can be put4 ,this should be securely fastened to the vessel1 and should dip into the liquid4 ,the liquor having been properly diluted1 is now heated by means of the steam pipes1 and the lime put into its cage4 ,it should be put in in lumps4 ,as the liquor reaches the boiling point1 the reaction will proceed rapidly1 and the lime will gradually disappear2 fresh lumps should be added if necessary4 ,if the liquor is sufficiently heated the causticising will be complete in from two to three hours4 ,the liquor should be tested from time to time2 this is usually done by a workman4 ,he withdraws a sample of the liquor1 and after allowing the calcium carbonate to subside1 pours off a portion of the clear liquid into a glass vessel4 ,he #aij then adds an excess of either sulphuric or hydrochloric acid4 ,if any effervescence takes place1 due to the evolution of carbonic acid gas1 he knows that the operation of causticising is incomplete2 the heating must therefore be continued4 ,it is difficult1 without an undue expenditure of time and steam1 to convert the whole of the soda into caustic3 it should however be so perfect1 that on testing only a very slight effervescence occurs4 ,it is quite easy to convert as much as #ie per cent4 of the soda1 or even more4 ,the actual amount converted can only be ascertained by a careful analysis of the liquor4 ,the amount of lime used is generally somewhat in excess of the theoretical quantity2 #ajf parts of sodium carbonate 7,na#b;,,co#c7 require #ef parts of lime 7,ca,o73 it is necessary1 however1 to add about #fj parts4 ,a very good plan is to conduct two or even three causticisings in the same vessel without cleaning out or removing the calcium carbonate1 using in the first operation a large excess of lime4 ,the causticising being completed1 the calcium carbonate and excess of lime are allowed to settle down1 and the clear liquor run off by an arrangement such as that already described in the dissolving process4 ,fresh solution is then run in and the whole mass heated for some time1 until the excess of lime is converted into carbonate4 ,fresh lime is then added if necessary until the conversion of the carbonate of soda is complete4 ,the liquor is then allowed to settle1 and is run off as before3 this operation may again be repeated4 ,the residual calcium carbonate1 or 8lime-mud0 as it is called in alkali works1 is then washed once or twice by running in water1 boiling up1 allowing to settle1 and running off the clear liquor4 ,if these liquors are too weak for use in boiling fibres1 they may be used for diluting fresh recovered soda liquor before causticising1 or for dissolving the soda4 ,some arrangement should be provided for removing as much as possible of the liquor from the lime-mud before throwing it away or otherwise disposing of it4 ,this is best done by throwing it on a filter made of layers of stones1 #aia ashes and sand1 and covered at the top with perforated iron plates4 ,the filter is connected with a vacuum pump4 ,in this way very perfect draining is accomplished1 and the mud forms a hard mass on the surface of the filter1 from which it can be easily removed with spades4 ,in this form it contains only #ej-fj per cent4 of water4 ,if properly washed it should contain in this state only about #b per cent4 of alkali 7,na#b,o74 ,by careful manipulation1 even this amount can be reduced4 ,the importance of thoroughly washing the mud can hardly be too much insisted upon4 ,where proper means are not employed for draining1 the washing should be made more perfect4 ,the lime-mud consists chiefly of carbonate of lime1 together with silicate1 free lime1 c4 ,the following analysis is of a mud obtained by causticising recovered soda derived from the liquors in which esparto and straw had been boiled3-- ,calcium carbonate #djjb ,calcium hydrate #eac ,silica #dja ,sodium hydrate #bac ,oxide of iron and alumina #jcj ,water #dhaj ,other constituents #jca #ajjjj ,as already pointed out the liquors contain a certain amount of soda1 as sodium sulphide and other sulphur compounds4 ,the presence of the former1 if in large quantities1 is objectionable1 as it is liable to discolour fibres boiled in liquors containing it4 ,it is therefore best to remove it4 ,this can be conveniently done by blowing air into the liquors during the process of causticising3 this has the effect of oxidising it to sulphate of soda1 in which form it is harmless4 ,the air can of course be blown into the liquor by means of a pump2 the most economical way is to connect with the steam pipe an injector constructed on the principle of the injectors used for feeding boilers and for other purposes4 ,by this means a strong current of air is drawn in1 and #aib being forced with the stream to the bottom of the liquor1 passes through it in a number of fine streams4 ,if the amount of sulphide present be very high it may be necessary to prolong the oxidising operation beyond the time necessary for complete causticising4 ,in many paper-mills the causticising is conducted in circular vessels furnished with mechanical agitators4 ,these are more expensive than the simple form described above1 and they possess no special advantages4 ,the use of causticisers in which neither mechanical agitation nor agitation by means of air is provided for is exceedingly wasteful of labour1 time1 steam1 and soda4 ,the lime-mud settles at the bottom as a hard mass1 very difficult to manipulate4 #aic ,,chapter ,,xiii4 ,,paper ,,testing4 ,there are two points of view from which a paper may be tested3 first1 of physical or mechanical properties2 secondly1 of material composition4 ,we shall consider the subject according to this division4 7,i47 ,quantitative measurements of such properties as resistances to breaking and tearing strains are seldom made by ,english paper-makers4 ,in ,germany1 on the other hand1 the matter has been very thoroughly investigated in connection with the work of the ,knigl4 ,techn4 ,versuchsanstalt1 ,berlin1 and through the agency and influence of ,prof4 ,sell1 and ,c4 ,hofmann1 a department has been organised exclusively for the work of paper testing4 ,the results of the tests are becoming widely recognised by practical men and the trade in that country1 as affording a true index of the quality of a paper4 ,it is therefore of importance to give an outline of the methods employed4 ,the determination of the strain or weight which a paper is capable of supporting is a very obvious measure of the strength of the paper4 ,observations of the limiting strain or breaking weight are sometimes made by paper-makers1 but the apparatus and method employed are usually crude4 ,the simplest means consist in clamping the paper--a strip of standard length and breadth1 arbitrarily chosen--at one end1 the clamp being firmly held in a fixed support1 and to the other attaching by means of a similar clamp1 an ordinary scale pan1 the whole arrangement hanging vertically4 ,into the pan1 weights are added in due succession until fracture of the strip is determined4 ,it is scarcely necessary to point #aid out that the errors of experiment with such a method are very great3 indeed it has been found that even with the refined apparatus about to be described the errors are not inconsiderable4 ,however1 by exhaustive investigation1 according to the well-known 8law of errors10 these have been quantified1 and a careful operator can therefore obtain results which are trustworthy4 ,the apparatus in question is the ,hartig-,reusch machine4#ad ,it is shown in sectional elevation and plan in ,figs4 #ge and #gf4 ,footnote #ad3 ,a complete description of this machine is given in #8,civil ,engineer1' #ahgi4 ,the principle will be readily grasped by inspection of the diagrammatic representation of its essential parts--,fig4 #gg4 ,the strip of paper is held horizontally by the clamps a and b1 a being held by the fixed support ,a1 b by the movable carriage ,b4 ,b is connected by means of a swivel with the spiral spring ,f1 and this again is similarly connected with the screw1 which is made to rotate by the wheel ,d4 ,by turning ,d1 therefore1 the spiral may be extended1 and a corresponding strain communicated through ,b and b to the paper4 ,the paper undergoes a certain elongation under the strain1 and the carriage ,b moves from right to left in consequence4 ,the rotation of the screw is continued1 and the extension of the spiral proceeds until the paper is fractured4 ,at this point it is required to determine1 7#a7 the elongation of the spiral which is the measure of the breaking strain1 and 7#b7 the distance through which the carriage has moved1 i4e4 the elongation of the paper4 ,both these effects are communicated to the pencil ,g1 the latter directly1 since the pencil-holder is in rigid connection with ,b1 the former through the rod ,i1 from which1 by a special arrangement1 the horizontal is converted into a vertical motion of the pencil4 ,this1 therefore1 traces a curve1 of which the ordinates represent the strains1 and the absciss the elongations of the paper produced by the strain4 ,the scale shown in ,fig4 #gf indicates the exact position of the clamp ,a4 #aie ,illustration3 ,,fig4 #gg4 ,illustration3 ,,fig4 #gf4 #aif ,the values for the spiral spring--i4e4 extension for a given load--having been determined by previous observations in a special apparatus1 the curve obtained is at once a measure and a permanent record of these cardinal factors1 breaking strain and elasticity4 ,as with all other such instruments1 the recording apparatus introduces certain errors1 which1 however1 by careful investigation and modification in accordance with the results1 have been reduced to a minimum4 ,nevertheless1 the director1 ,dr4 ,martens1 has recently adopted a simpler instrument1 altogether similar in principle1 but based upon a direct reading of the two movements1 in which of course these errors do not appear4 ,for the student1 however1 the recording instrument is the more instructive1 and we have given it preference for description here1 more especially as no difference in essential parts is involved4 ,those who wish to pursue the matter into the most interesting details of the investigations made upon the subject1 are referred to the papers published by the ,institute for #ahhe4ae ,footnote #ae3 ,mittheilungen a4 d4 ,knigl4 ,techn4 ,versuchsanst1 ,berlin4 ,in testing the strength of papers by this or similar machines1 it is important to observe the hygrometric state of the atmosphere at the time the trials are made1 as this has been found to exert a considerable influence on the results1 a paper being weaker the moister the atmosphere4 ,the results of the tests are expressed in the following terms3--,the elongation is given directly in percentage of the original length4 ,this is uniformly taken at #ahj mm41 a length arrived at after laborious investigation1 as minimising the errors of experiment2 in other words1 as giving mean value with the minimum of variation4 ,for the breaking strain an ingenious expression has been arrived at1 viz4 the length of the paper which suspended vertically1 with one end hanging freely1 the other fixed1 would determine fracture at the fixed end4 ,as the breaking strain would vary with the thickness1 the numbers obtained in #aig units of force or weight for strips of constant breadth1 would need correction in order to admit of strict comparison with one another4 ,by substituting an expression in terms of the paper itself--since a paper of greater thickness1 and requiring therefore a proportionately greater force to fracture it1 weighs more per unit of area1 and in the same proportion--all the numbers for breaking strains are strictly comparative one with the other4 ,in the same way also the question of width may be disregarded4 ,a further mechanical test1 forming a part of the scheme of investigation1 is the resistance of the paper to rubbing4 ,this test is an altogether empirical one1 as the following brief description will show3--,a piece of the paper1 about #f inches square1 crumpled by successive folding in two directions at right angles1 is grasped by the thumb and forefinger of each hand1 at a distance of #c-d inches apart4 ,it is then rubbed upon itself across the thumbs a given number of times 7seven is the number chosen7 and held up to the light4 ,if no holes are visible1 the rubbing is repeated4 ,the number of times necessary to repeat the rubbing until holes appear is the measure of the resistance4 ,a sufficient uniformity in the results of this test has been observed to make it the basis of a classification of papers1 in regard to their resistance to such disintegration2 they are divided into the following eight groups1 beginning with the lowest3-- #j4 ,extremely weak4 #a4 ,very weak4 #b4 ,weak4 #c4 ,medium4 #d4 ,moderately strong4 #e4 ,strong4 #f4 ,very strong4 #g4 ,extremely strong4 ,the classification of papers on the results of these tests cannot be more lucidly given than in the following scheme1 under which the results are officially recorded3-- ,class4 #a #b #c #d #e #f a4 ,mean breaking length 7metres7 not less than #fjjj #ejjj #djjj #cjjj #bjjj #ajjj b4 ,mean elongation 7per cent47 at fracture not less than #de #d #c #be #b #ae c4 ,resistance to rubbing #f #f #e #d #c #a #aih ,this classification is based on the results of some hundreds of observations4 ,it is interesting to note the differences observed in the numbers for a and b according to the direction for the test in which the paper is cut1 i4e4 in the direction in which it was run on the paper machine1 or at right angles 7see ,chap4 ,,xi4 p4 #aga74 ,the mean ratio for the breaking lengths 7strains7 may be taken as #a 3 #af1 i4e4 the paper is about #dj per cent4#af weaker across the web2 the elongation under strain on the other hand is about double4 ,footnote #af3 ,in the statement of results the mean of the numbers obtained in the two directions is given4 ,it is also of interest to note the influence of the glazing process 7p4 #afg7 upon the quality of the paper as determined by these tests4 ,first1 we must notice the effect of the treatment upon the substance of the paper itself4 ,the mean reduction of thickness is #bc per cent4 ,on the other hand1 the reduction of weight1 calculated per unit of surface 7square metre71 is #fg per cent41 whence we may infer an increase of surface1 flattening out1 in the process4 ,these quantities1 but more particularly the latter1 will doubtless vary with the various methods of glazing and with the materials of which the paper is composed4 ,the breaking length 7strain7 shows a mean increase of about #h per cent42 the elongation under strain1 on the other hand1 a diminution of #f per cent4 ,for an interesting discussion of the question of the relative strengths of machine and hand-made paper see #8,paper1' by ,richard ,parkinson4 ,illustration3 ,,fig4 #gh4 ,the thickness of a paper may be determined by means of an ordinary micrometer1 such as is shown in ,fig4 #gh4 ,the paper is placed in the jaws of the instrument1 and the screw #aii advanced until it touches the paper4 ,the thickness is then read off on the scale4 ,other forms of apparatus are sold for the same purpose4 ,in making a determination of the thickness of a paper it is necessary to take the mean of a series of observations at different points of the sheet1 as the thickness may vary somewhat4 ,determination of ,composition of ,papers4 7,,ii47 ,the analysis of a paper naturally divides itself into two parts3--7a7 ,the determination of the nature of the fibrous material of which it is composed2 and 7b7 the identification of such adventitious substances as size and filling material4 7a7 ,this again is divided into two sets of observations--microscopical and chemical4 ,a fragment of the paper is soaked for some time in glycerine1 and is then carefully teased out with a pair of needles1 and the fragments laid on a glass slip with a drop of glycerine4 ,a cover-glass is then laid on and lightly pressed down so as to spread the fibres in a thin layer4 ,the microscopical features of the different fibres have been already described1 and it is only necessary now to summarise the chief characteristics of the more important materials4 ,cotton4--,flat riband-like fibres1 frequently twisted upon themselves4 ,the ends generally appear laminated4 ,the fibres are frequently covered with numerous fine markings 7see ,frontispiece74 ,linen4--,cylindrical fibres1 similar to the typical bast fibre 7see ,fig4 #f74 ,the ends are frequently drawn out into numerous fibrill 7see ,frontispiece74 ,esparto4--,esparto pulp consists of a complex of bast fibres and epidermal cells4 ,these serrated cells are1 as has been already pointed out1 characteristic of esparto1 straw1 and similar fibres4 ,certain differences exist between those of esparto and straw1 and even between the different species of straw1 which enable the microscopist to identify their source4 ,the most characteristic feature of esparto pulp is the presence #bjj of a number of the fine hairs which line the inner surface of the leaf 7e1 ,fig4 #aj71 some of which invariably survive the boiling and washing processes1 although the greater portion passes away through the wire-cloth of the washing engines4 ,the presence of these hairs may be taken as conclusive evidence of the presence of esparto4 ,straw4--,straw pulp very closely resembles esparto-pulp in its microscopical features4 ,the hairs above alluded to are1 however1 absent4 ,on the other hand1 a number of flat oval cells are always present in paper made from straw 7b1 ,fig4 #ac74 ,it should be borne in mind1 however1 that bamboo and similar pulps also contain these cells4 ,wood 7,chemical74--,flat riband-like fibres1 showing unbroken ends 7see photographs1 ,frontispiece74 ,the presence of the pitted vessels 7,frontispiece1 and a1 ,fig4 #ae7 is eminently characteristic of pulp prepared from pine-wood4 ,the fibres of other woods are not sufficiently characteristic4 ,they much resemble those of pine-wood1 with this difference1 that the pitted vessels are absent4 ,wood 7,mechanical74--,mechanical wood-pulp may be recognised by the peculiar configuration of the torn ends of the fibres1 and from the fact that the fibres are rarely separated1 but are generally more or less agglomerated 7see ,frontispiece74 ,pulp from pine of course shows the pitted vessels already referred to4 ,they are usually more distinct than in chemical wood-pulp4 ,occasionally fragments are to be met with connected together with portions of the medullary rays4 ,the microscopical examination of a paper is a matter of very great difficulty1 and one requiring much practice4 ,the student is recommended to study closely for himself the microscopical features of pulps obtained from authentic specimens4 ,some approximate idea of the relative proportion of the various fibres present in a paper can be obtained from a careful microscopical examination4 ,vtillart maintains that a quantitative determination within a fair limit of accuracy is possible4 ,on the other hand1 the #bja ,berlin ,prfungsanstalt do not profess to do more than merely identify the fibres4 ,in examining a paper under the microscope1 it should be observed whether the fibres appear as fragments1 or whether they consist of whole bast cells in which the tapered ends appear4 ,cotton and linen1 owing to the great length of their ultimate fibres1 yield1 when beaten1 fragments showing where the fracture has taken place4 ,from the appearance of this fracture it is possible to ascertain whether or not the beating operation has been properly conducted4 ,if the beater-knives have been too sharp1 or have been let down to the bed-plate too quickly1 the fractures will appear as clean cuts1 whereas when the operation has been properly conducted the fracture will appear ragged and drawn out4 ,the bearing of this on the strength of the finished paper is considerable4 ,esparto1 straw1 and wood1 whose ultimate fibres do not exceed #a-b mm41 should1 in the majority of cases1 appear as whole bast fibres with two tapered ends2 the beating1 when properly conducted1 being confined merely to the separation into these ultimate fibres4 7b7 ,for the chemical identification of the fibres in a paper1 the only available reactions are those with aniline sulphate solution4 ,the majority of fibres 7celluloses7 give no reaction1 straw and esparto celluloses and mechanical wood-pulp being the only ones that can be identified by its means4 ,the authors have found that when a paper containing straw or esparto is treated for some time with a boiling #a per cent4 solution of aniline sulphate1 a pink colour is produced4 ,esparto gives the reaction with greater intensity than straw4 ,in this way the presence of a very small quantity of these pulps can be detected with certainty4 ,mechanical wood-pulp1 when treated with a solution of aniline sulphate1 develops1 even in the cold1 a deep yellow colour4 ,if a paper containing mechanical wood-pulp so treated be examined under the microscope1 the fragments of wood will be found to be deeply stained1 whereas the other #bjb fibres remain colourless or nearly so4 ,it must be borne in mind that cellulose obtained from lignified fibres1 if the boiling and bleaching processes have not been carried sufficiently far1 will give with aniline sulphate a more or less intense yellow coloration4 ,various other reagents have been suggested for the identification of mechanical wood-pulp1 all based upon the production of a colour with lignose4 ,the reaction of lignose with chlorine and sodium sulphite solution already referred to 7p4 #ai7 may also be made available for the detection of mechanical wood-pulp in a paper4 ,imperfectly boiled or bleached pulps sometimes give this reaction faintly4 ,quantitative ,estimation of ,mechanical ,wood-pulp4--,the determination of the amount of mechanical wood-pulp present in a paper is sometimes a matter of some importance1 and it is also a matter of great difficulty4 ,some idea of the amount present can be obtained by observing the depth of the yellow colour produced with aniline sulphate or the intensity of the magenta reaction with chlorine and sodium sulphite4 ,it is also possible to calculate approximately the percentage from the percentage of cellulose contained in the specimen4 ,mechanical wood-pulp 7pine7 may be taken to contain #fj per cent4 of cellulose4 ,if1 therefore1 a paper ascertained to contain a pure cellulose in addition to this constituent1 yield #ge per cent4 of cellulose on the ordinary test1 it may be assumed that about #fbe per cent4 of mechanical wood-pulp is present4 ,the authors have proposed a method of estimating the amount of mechanical wood-pulp present in a paper1 based upon the absorption of iodine in definite proportions by wood in a finely divided state1 under strictly regulated conditions4 ,the paper is carefully reduced to a fine pulp1 and is then left in contact with a standard solution of iodine in potassium iodide4 ,at the end of twenty-four hours the amount of free iodine is determined by titration with sodium thiosulphate and by deducting this from the amount originally taken1 the amount absorbed is ascertained4 ,as this amount1 under #bjc strictly comparative conditions1 always corresponds to a definite amount of mechanical wood-pulp the amount present can be readily calculated4 #b4 ,loading1 ,sizing ,materials1 c4--,the determination of the amount of loading material in a paper has been already described 7p4 #acd74 ,the identification of the material can only be arrived at by a careful chemical analysis4 ,the principal loading materials are china-clay and pearl-hardening 7calcium sulphate74 ,the ash from a paper containing china-clay is insoluble in boiling dilute hydrochloric acid2 that from paper containing calcium sulphate is soluble3 the solution on cooling deposits long needle-shaped crystals of ,ca,s,o#d #b ,h#b,o and gives with barium chloride a copious precipitate of ,ba,s,o#d 7barium sulphate7 insoluble in acids1 and with ammonia and oxalate of ammonia a precipitate of calcium oxalate4 ,the presence of starch in a paper can be readily ascertained by its behaviour with a solution of iodine4 ,if starch be present the well-known blue colour of the compound of iodine and starch will be produced4 ,the determination of the amount of starch present is a matter of some difficulty1 the details of which are somewhat beyond the scope of the present work4 ,it is based upon the conversion of the starch into sugar1 and the estimation of the latter with ,fehling's solution4 ,the nature of the material with which a paper is sized may be ascertained in the following way3-- ,the sample1 cut up into small fragments1 is warmed for a few minutes with alcohol containing a few drops of acetic acid4 ,the alcohol is allowed to cool1 and is then poured into four or five times its bulk of distilled water4 ,if any precipitate or cloudiness is produced1 it indicates that the paper has been sized with rosin4 ,the alcohol dissolves the rosin1 which1 being insoluble in water1 is thrown down on dilution4 ,the alcohol used should be previously purified by distillation1 as some samples contain a small quantity of shellac1 which would itself be precipitated with water4 #bjd ,the paper after treatment with alcohol should now be boiled for some minutes with water3 the solution allowed to cool1 and then filtered4 ,to the filtrate a few drops of a solution of tannic acid are added1 when1 if the paper has been sized with gelatine1 a white curdy precipitate will be formed4 ,the estimation of the amount of sizing material in a paper is a very complicated process and one which demands considerable chemical experience for its proper conduct4 ,the amount of gelatine present is best ascertained by determining the amount of nitrogen present by combustion with soda-lime1 and from this1 calculating the amount of gelatine4 ,pure gelatine contains #ahaf per cent4 of nitrogen 7,muntz74 ,the comparison of one paper with another with a view to ascertain the relative degree of sizing1 is usually performed in a more or less rough and ready way by moistening the samples with the tongue for a certain time1 and noticing the degree of transparency produced1 which is of course inversely to the degree of hardness4 ,a more accurate method consists in placing a drop of a mixture of alcohol and water containing some colouring matter in solution and determining the time necessary for the colour to make its appearance on the other side4 ,in this way more trustworthy comparisons can be made4 ,colouring ,matters4--,the chemical reactions of the chief colouring matters have been already described 7p4 #ada74 #bje ,,chapter ,,xiv4 ,,general ,,chemical ,,analysis ,,for ,,paper-,,makers4 ,a knowledge of the methods usually employed for the qualitative and quantitative analysis of the various chemical substances met with in paper manufacture is of considerable importance4 ,the scope of this work will not allow us to enter fully into the necessary details of manipulation2 for these the reader is referred to standard works on analysis2 we will merely indicate the methods4 ,caustic ,soda1 ,soda ,ash1 ,recovered ,soda1 c4--,these substances are always valued by the amount of real alkali 7,na#b,o7 that they contain1 which is determined by titration with a standard acid4 ,in testing recovered soda1 it is necessary to boil the finely powdered ash for some time with water2 unless this be done1 the amount of alkali will probably be under-estimated1 as part of the soda is present as a difficultly soluble silicate4 ,it is sometimes desirable to determine the amount both of sodium hydrate and carbonate in a sample of alkali4 ,for this purpose an excess of a solution of barium chloride is added to a solution containing a known quantity of the substance under examination1 and the mixture made up to a definite volume4 ,it is then filtered1 and an aliquot portion of the filtrate titrated with standard alkali4 ,the filtrate contains only the alkali that was originally present as hydrate1 the carbonate of soda having formed with the barium chloride1 insoluble barium carbonate1 and sodium chloride4 ,bleaching ,powder4--,the value of bleaching powder #bjf depends upon the amount of available chlorine that it contains4 ,this is determined by means of a standard solution of arsenious acid4 ,the standard solution is prepared by dissolving pure arsenious oxide 7,as#b,o#c7 in sodium carbonate solution4 ,to test the powder1 a quantity1 say about #e grms41 is taken1 and is carefully ground up in a mortar with a small quantity of water1 more water is then added1 and the coarser particles allowed to settle for a few seconds4 ,the milky liquid is then run off into a graduated flask2 the residue is again ground up with water1 and the operations repeated until the whole of the powder is transferred to the flask4 ,the flask is now filled up to the proper mark1 carefully shaken1 and an aliquot portion withdrawn as quickly as possible4 ,it is necessary to take both the soluble and insoluble portions in order to obtain uniform results4 ,standard arsenious acid solution is now run in until the solution ceases to produce a blue colour with iodide of potassium and starch papers4 ,the method of estimating the amount of available chlorine in bleaching powder by determining the quantity of ferrous sulphate it is capable of oxidising is fallacious1 as by this means calcium chlorate is included in the result4 ,bleaching powder should contain about #ce per cent4 of available chlorine1 but the percentage frequently falls below this amount1 especially in warm weather4 ,great care should be exercised in the sampling of bleaching powder1 as indeed of all chemicals1 in order to insure an average result4 ,small portions should be taken from different parts of the bulk2 the whole should then be carefully mixed1 and1 if necessary1 reduced to powder4 ,portions of the mixture should be taken1 pounded1 and again thoroughly mixed4 ,if this process be repeated once or twice1 a perfectly uniform sample will be obtained4 ,alum1 ,sulphate of ,alumina1 ,alum ,cake1 c4--,the points to be considered in an examination of these products are 7#a7 the percentage of alumina contained in them2 7#b7 the #bjg percentage of iron1 and 7#c7 the amount of free sulphuric acid present4 7#a7 ,the alumina is estimated as such by precipitation with ammonia4 ,ferric oxide is also thrown down with alumina1 and must therefore be deducted from the amount of the mixed oxides obtained4 7#b7 ,the percentage of iron oxide present is determined in the following way4 ,a considerable quantity of the sample under examination is dissolved in water1 and to the boiling solution a large excess of caustic potash solution is added4 ,the caustic potash precipitates both the alumina and ferric hydrates1 the former1 however1 redissolves4 ,the solution is filtered1 and the precipitate of ferric hydrate washed1 dissolved in dilute hydrochloric acid1 and reprecipitated with excess of caustic potash4 ,it is again thrown on to a filter1 washed1 redissolved in hydrochloric acid1 and again reprecipitated with ammonia4 ,in this way it is obtained free from alumina4#ag ,footnote #ag3 ,for a method of estimating minute quantities of iron in alums see #8,journ4 ,soc4 ,chem4 ,ind41' ,april #ahhg1 p4 #bgf4 7#c7 ,free ,acid4--,this can be estimated indirectly1 i4e4 by estimating the alumina and ferric oxide1 calculating the amount of sulphuric acid necessary to combine with them1 and deducting this from the total amount of sulphuric acid obtained4 ,in the case of alum it is of course necessary to make due allowance for the sulphate of potash or ammonia present4 ,the sulphuric acid is estimated as barium sulphate in the usual way4 ,it should be borne in mind that sulphates of alumina are sometimes met with containing uncombined alumina4 ,a convenient method of estimating free acid consists in digesting a weighed quantity of the finely powdered sample in strong alcohol4 ,the alcohol dissolves away the free acid1 which can be estimated in the solution by means of a standard solution of alkali4 ,free acid can be detected by means of a solution of #bjh ,congo-red1 which is turned blue with free acid1 but not with pure sulphate of alumina4 ,antichlor1 ,sodium ,thiosulphate1 ,sodium ,sulphite1 c4--,sodium thiosulphate can be estimated by means of a standard solution of iodine in potassium iodide4 ,the operation should be performed in dilute solution 7see p4 #aaa74 ,the same solution serves also for the estimation of sulphurous acid in sodium and other sulphites4 ,starches4--,after having made a careful microscopical examination of the sample1 it should be examined for water by drying at #ajj;,c41 and for mineral matter by igniting in a platinum crucible and weighing the residue4 ,the water should not exceed #ah per cent41 and the ash #ej per cent4 ,the samples should be carefully examined for insoluble matter by dissolving in water and filtering4 ,it is also useful in comparing different samples of starch to convert the specimens into pastes1 under exactly similar conditions4 ,when perfectly cold1 the 8stiffness0 of the pastes should be compared4 ,this may be done by noting the relative resistance to weights placed upon their surface4 ,information on this subject is contained in a paper by ,w4 ,thomson in the #8,journ4 ,soc4 ,chem4 ,ind41' ,march #ahhf4 ,the identification of starches by means of their microscopical appearances is tolerably simple1 as each particular kind possesses characteristic differences4 ,gelatine4--,samples of gelatine should be examined for water and ash4 ,the water should not exceed #af per cent4 and the ash #bg per cent4 ,the relative strengths of the jellies formed with water should also be compared4 ,this may be done in the way indicated above for starches4 ,raw materials intended for the preparation of gelatine may be similarly examined4 ,they yield the whole of their gelatine on heating with water4 ,the effect of prolonged heating on solution of gelatine should be borne in mind4 ,the amount of residue left after treatment with water should be carefully determined4 ,soaps4--,the soaps most suitable for use in paper-making #bji are those known as curd and mottled1 the former being chiefly used for the fine qualities4 ,they should be carefully examined for free alkali and unsaponified fat4 ,full descriptions are contained in ,lant ,carpenter's #8,treatise on ,soap-making4' ,dyes1 ,pigments1 ,loading ,materials1 c4--,these substances are best examined from a physical and tinctorial point of view1 by comparison with specimens of undoubted purity and excellence4 ,the chemical examination is both difficult and somewhat misleading4 ,a microscopical examination will often throw much light on their composition4 ,for comparing the tinctorial power of different samples1 weighed quantities should be ground up with starch or some other white powder4 ,in this way some idea of the intensity of colour can be readily arrived at4 #baj ,,chapter ,,xv4 ,,site ,,for ,,paper-,,mill1 ,,water-,,supply1 ,,water ,,purification1 ,,etc4 ,in choosing a spot on which to build a paper-mill1 the manufacturer has to take into consideration several very important circumstances4 ,chief of these is the necessity for having a large supply of water at command4 ,not only is a large quantity needful1 but it should be free from impurities1 such as suspended matter and iron4 ,the former1 it is true1 can be removed by settling and filtration2 the latter cannot1 and is liable to injuriously affect the colour of the paper4 ,again1 as a question of economy in working1 it is advantageous to have convenient water-power2 therefore for this1 as well as for the former reason1 paper-mills are usually situated on the bank of a stream4 ,in choosing such a site1 paper-makers are probably also influenced by the fact that it affords a ready means for the removal of impurities4 ,in properly conducted mills1 where suitable apparatus is employed for evaporating the liquors in which the raw material has been boiled1 the stream should not be polluted to any very great extent4 ,generally speaking1 the greater the pollution1 the more are valuable materials being lost to the manufacturer4 ,it is obvious that the site for a mill should also be chosen with reference to its proximity to means of transit for the raw and manufactured materials4 ,the disposition of the different divisions of a paper-mill depends of course upon the nature of the paper it is intended to make and to a large extent upon local circumstances4 ,fig4 #gi will give some idea of the general arrangement of a mill for manufacturing esparto paper4 #baa ,water ,purification4--,arnot in his ,cantor ,lectures on the ,technology of the ,paper ,trade states that from #cj1jjj to #dj1jjj gallons of water are required for the manufacture of each ton of paper4 ,the importance of a pure and copious supply is therefore very evident4 ,illustration3 ,,fig4 #gi4 ,the impurities of water consist of two classes1 insoluble and soluble4 ,the former can be readily removed by processes of settling and filtration4 ,for this purpose most paper-mills are provided with large ponds capable of holding several days' supply4 ,these are sometimes supplemented by filtering beds4 ,insoluble impurities can also be removed by passing the water through filter-presses4 ,fig4 #hj is an illustration of ,rckner's patent clarifier1 which may also be applied to this purpose4 ,the cylinders ,c dip below the surface of the water to be purified1 which is contained in the reservoir ,a4 ,they are open at their lower ends1 but are closed at the top by the domes ,d4 ,these are connected with the pump ,i by means of the pipes ,h4 ,on starting the pump the water rises slowly in the cylinders4 ,as soon as it reaches the level of the top1 the action of the pump is stopped and the cocks ,k opened1 when the water commences to flow down the pipes ,g1 which together #bab with the cylinders form a kind of siphon4 ,if the reservoir ,a be kept full1 the siphons can be made to act continuously4 ,the flow of water being slow1 insoluble impurities have time to subside4 ,the impurities may from time to time be removed by means of the small pump ,l connected with the bottom of the reservoir4 ,the clarifier can also be used for the purification of the effluent water from paper-mills4 ,illustration3 ,,fig4 #hj4 ,insoluble impurities can be removed from water by means of the ,stanhope purifier1 shown in ,fig4 #ha4 ,the soluble impurities of water consist mainly of carbonate and sulphate of calcium and iron1 and occasionally organic matter4 ,it is a moot point among paper-makers #bac whether or not the presence of the two former in a water is objectionable4 ,for boiling and bleaching purposes it undoubtedly is1 as when mixed with caustic soda or bleaching liquor they form a precipitate of carbonate of calcium1 which lines the insides of boilers1 breakers1 and potchers as a hard scale1 which is always liable to become detached1 and to find its way into the finished paper4 ,moreover1 carbonate of calcium is precipitated in the fibre1 and carries with it a certain quantity of colouring matter1 the subsequent removal of which is difficult4 ,carbonate of calcium1 though practically insoluble in pure water1 is soluble in water containing carbonic acid4 ,when this carbonic acid is neutralised by lime or soda1 the carbonate is precipitated4 ,the sulphate of calcium is unacted upon by lime1 but by the action of caustic soda is converted into free lime and sodium sulphate4 ,the lime then neutralises the free carbonic acid in the water1 and forms carbonate of calcium1 which is of course precipitated4 ,these reactions may be represented by the following equations3-- ,calcium ,carbonic ,lime4 ,calcium carbonate4 acid4 carbonate4 #a4 ,ca,c,o#c ,,co#b ,ca,o #b ,ca,c,o#c4 ,calcium ,caustic ,calcium ,sodium sulphate4 soda4 hydrate4 sulphate4 #b4 ,ca,s,o#d #b ,na,o,h ,ca,h#b,o#b ,na#b,,so#d4 ,calcium ,carbonic ,calcium ,water4 hydrate4 acid4 carbonate4 ,ca,h#b,o ,,co#b ,ca,c,o#c ,h#b,o4 ,if sodium carbonate be used instead of caustic soda1 the decomposition will take place thus3-- ,calcium ,sodium ,calcium ,sodium sulphate4 carbonate4 carbonate4 sulphate4 ,ca,s,o#d ,na#b;,,co#c ,ca,c,o#c ,na#b,,so#d4 ,it will be seen from the above equation that in the boiling processes the lime salts are removed from the water at the expense of an equivalent quantity of caustic soda4 ,the amount thus decomposed is not sufficiently large to make it advisable #bad on that account to purify the water4 ,it is indeed so small that processes of purification1 based upon the use of lime and caustic soda1 are now largely used1 the cost for chemicals rarely exceeding #a;d4 per #ajjj gallons4 ,but for the reasons we have stated above1 and also from the fact that it serves to remove dissolved iron and organic matter from a water1 such a purification process is in certain cases advisable4 ,the processes now in use consist1 as we have indicated1 in the addition to the water of lime and caustic soda or carbonate of soda1 the quantities being regulated according to the hardness of the water1 and the relative proportions of carbonate and sulphate of calcium4 ,the method of removing carbonate of calcium from water by the addition of lime is due to the late ,dr4 ,clark1 of ,aberdeen1 and the process is still called after him4 ,it is in use in its original form in many places4 ,the plant necessary consists simply of a tank for mixing the water and the lime1 and of large settling tanks in which the carbonate of calcium subsides4 ,various modifications of this process have been proposed1 chiefly in the direction of improved plant4 ,in the ,porter-,clark process the carbonate of calcium is removed by passing the water after the addition of lime 7in the form of lime-water7 through a filter-press4 ,illustration3 ,,fig4 #ha4 ,in ,fig4 #ha is shown the ,stanhope purifier1 which is largely used for the purpose of softening water4 ,the following details will render its action clear3 ,a is a store tank containing caustic soda solution4 ,b is a tank into which the water to be treated flows1 and which is maintained at a constant level by means of a valve and float4 ,c and ,c are two tanks which are used alternately1 and in which lime water is prepared4 ,a definite quantity of caustic soda solution is added from ,b2 this mixture forms the reagent by which the softening of the water is accomplished4 ,d is a small tank for the purpose of maintaining a constant head of reagent4 ,the reagent and the water are mixed together in the pipe ,f1 the quantities being regulated by the cocks #baf shown at ,h4 ,the pipe ,f leads into the vessel ,e1 which is fitted with a number of ,v-shaped shelves1 placed at an angle of #de1 and riveted alternately to opposite sides of the vessel4 ,this arrangement causes the water to take a serpentine course4 ,the position of the shelves is indicated by the dotted lines4 ,as soon as the mixture of water and reagent flows down the pipe ,f1 and enters the vessel ,e1 the calcium carbonate commences to precipitate and settles upon the ,v-shaped shelves4 ,at the top of the tank a layer of wood shavings1 inclosed in wire-netting1 is placed as shown by the dotted lines4 ,this acts as a filter1 and intercepts any particles that may not have subsided4 ,the clear purified water passes away by the pipe ,i4 ,the precipitate that collects on the ,v-shaped plates is from time to time drawn off by the cocks shown at ,g2 this may be done without interfering with the working of the apparatus4 ,while there can be no doubt that the use of soft water is advantageous in the boiling1 washing1 and bleaching processes1 and also of course for supplying steam boilers1 it is probably an advantage to use a hard water for diluting the pulp before running it into the machine4 ,in the case of papers which are loaded with any of the forms of calcium sulphate 7pearl-hardening1 crystal-hardening1 c47 the use of very soft water is objectionable from the fact that a certain quantity of calcium sulphate is dissolved4 ,this would not take place to the same extent with water which is already charged with sulphate and carbonate of calcium4 ,the removal of soluble iron from a water is effected by the softening processes described4 #bag ,,chapter ,,xvi4 ,,action ,,of ,,cuprammonium ,,on ,,cellulose4 ,,preparation ,,of ,,willesden ,,paper4 ,the action of a solution of copper oxide in ammonia upon cellulose has been already referred to 7see p4 #e74 ,celluloses1 and also lignocelluloses1 when treated with such a solution1 gradually gelatinise and finally dissolve4 ,on evaporating the solution to dryness1 a gummy amorphous mass is obtained1 containing the cellulose intermixed with copper oxide4 ,if the cellulose be in excess1 e4g4 when the solution is evaporated on the surface of paper1 calico1 c41 merely dipped in the solution1 the copper oxide is often not formed at all1 but a green varnish-like mass of cellulose combined with copper oxide1 which coats the surface of each filament1 welding and cementing them together4 ,this cement-like cupro-cellulose1 as it may be termed1 being insoluble in water1 communicates water-resisting properties to the material so treated3 moreover1 the presence of copper renders the fabric less prone than before to be attacked by insects and mould1 so that animal and vegetable life of a parasitic nature and fungoid growths are rarely1 if ever1 to be observed1 even when the material is kept under conditions where boring worms1 ants1 rot1 and mould1 would be likely to attack it4 ,as has been already indicated 7p4 #e71 the solution of cuprammonium hydroxide is preferable to one containing cuprammonium salts2 not only is the action on cellulose more energetic1 but various other advantages are obtained4 ,preparation of the ,copper ,solution4--,the cuprammonium solution is prepared according to the patent of ,dr4 ,c4 ,r4 ,alder ,wright 7,no4 #gcg1 #ahhc74 #bah ,a series of cast-iron towers1 two to three feet in diameter and ten to twelve feet high1 is so arranged that a current of air can be blown by a powerful engine successively through the whole series4 ,the towers are then nearly filled with fragments of metallic copper 7crumbled up sheet1 cuttings1 c471 and solution of ammonia3 the air-current being turned on1 oxidation of the copper and solution of the oxide so produced are rapidly effected4 ,the ammonia solution employed is previously impregnated with a considerable quantity of copper by passing a stream of water over scrap copper in similar towers1 a current of ammonia gas mixed with a suitable proportion of air being at the same time forced in4 ,the liquor passing from one tower is used over again to supply a second instead of water1 and so on through the series3 finally the liquor is brought up to full copper strength in the series of towers described above4 ,the spent air issuing from the towers carries with it a notable quantity of ammonia2 this is intercepted by means of an 8exhaust0 scrubber containing copper1 and well supplied with water1 whereby a comparatively weak solution of ammonia and copper is obtained1 which can be used instead of water in the first series of towers4 ,in order to produce the maximum effect on the cellulose1 the solution should contain from #ajj to #aej lbs4 of ammonia1 and from #bj to #be lbs4 of copper per #ajj gallons4 ,by decomposing a cuprammonium solution by means of metallic zinc1 a corresponding solution of zinc-ammonium hydroxide can be obtained4 ,this solution is also capable of gelatinising cellulose1 but not to the same extent as the copper solution4 ,it may1 however1 be advantageously employed in certain cases in conjunction with a copper solution4 ,such a solution can be conveniently prepared by substituting brass for copper in the dissolving-towers4 ,it is worthy of note that although1 as we have seen1 zinc has the power of replacing copper in a cuprammonium solution1 iron is without any action1 although it readily replaces copper in a solution #bai of copper sulphate4 ,this fact is of very great industrial importance1 as it enables the manufacturer to employ vessels and machinery of iron4 ,the 8,willesden0 goods may be divided into two classes4 ,goods of the first class1 such as rope1 cordage1 netting1 c41 are prepared by simply dipping the made-up materials in a bath of cuprammonium solution1 using certain precautions as to the mode of immersion and its duration1 and the strength of the solution4 ,on subsequently drying the dipped fabrics1 they are obtained coated and impregnated with cupro-cellulose1 which thus not only forms a kind of varnish-like surface dressing1 but further adds strength to the fibres by more or less intimately cementing them together4 ,goods of the second class constitute a much more important group to which at present the ,willesden ,company more especially devotes its attention4 ,these fabrics are essentially of three kinds1 viz4 ,willesden ,canvas1 ,willesden ,scrim1 and ,willesden ,paper4 ,the two former of these classes are prepared in much the same way as the goods just described1 saving that the fabric to be treated is usually unwound from one roller and rewound upon another1 after passing through the bath and over a succession of drying cylinders4 ,willesden ,paper4--,this may be divided into two departments1 viz4 7#a7 ,willesden unwelded2 7#b7 ,willesden welded1 the first class being prepared from a single web of paper by passing it through the bath1 rolling and drying4 ,certain coarse varieties furnish a waterproof material excellently adapted for lining packages1 c4 ,finer qualities furnish envelopes and stationery1 possessing the valuable property of not being affected by water4 ,letters written on such paper would remain perfectly legible1 even after prolonged immersion4 ,it may be interesting to point out here that the cuprammonium solution offers a very simple means of fastening envelopes in such a way as to be proof against any attempts at tampering4 ,the method consists in using a concentrated solution as the fastening material2 the envelope #bbj is then closed and ironed with a warm flat-iron1 whereby the gelatinised cellulose is converted into an insoluble cupro-cellulose1 and the cover is fastened so securely that the only possible mode of opening is by tearing the paper4 ,willesden ,welded ,goods are prepared by simultaneously dipping two or more sheets of paper and pressing them into one compact homogeneous sheet whilst the surfaces are still in a gelatinous state4 ,in this way a continuous length of fabric of extraordinary durability is produced that is scarcely affected by water1 even when heated in it for some weeks at a pressure of #fj lbs4 per square inch4 ,as1 on drying fabrics treated with cuprammonium solution1 the whole of the ammonia in the solution absorbed by them is volatilised1 it is necessary1 in order to make the process economical1 to collect and re-use this ammonia4 ,this is effected by conducting the drying process in closed chambers1 from which the ammonia gas is conducted by suitable appliances and recovered4 ,in addition to the advantages already mentioned1 it may be stated that ,willesden paper is much less inflammable than ordinary paper4 ,among the many uses to which ,willesden goods can be applied1 the following may be cited3--,roofs and sheds2 huts and tents2 partitions2 tanks and pipes2 damp-proof foundations2 underlining slates2 sails1 awnings1 c4 c4 #bba ,,chapter ,,xvii4 ,,statistics4 ,raw ,materials4 ,the statistics concerning the trade in raw materials for paper-making are not published in a detailed form1 all the various kinds of fibre1 c41 being grouped under two heads1 viz4 rags 7linen and cotton71 and esparto 7which embraces other fibres1 and probably wood pulps74 ,the figures for recent years are shown in the accompanying tables3-- 7a7 ,imports of cotton and linen rags3 tons4 l4 #ahhj4 #bi1fdb #dea1ghb #ahha4 #bf1ggc #cif1bgd #ahhb4 #ba1bjj #cjc1cdi #ahhc4 #bh1edc #dja1ibb #ahhd4 #cf1bcc #dhg1hff #ahhe4 #ce1dgj #dff1ibh 7b7 ,esparto and other material3 tons4 l4 #ahhj4 #bbh1ehj #a1fdb1ijc #ahha4 #bch1jdc #a1fbf1hjj #ahhb4 #bea1eid #a1ghd1jgh #ahhc4 #bhh1edi #a1idc1gcb #ahhd4 #bfj1edd #a1fch1efd ,but a portion of these imports was exported again1 the figures being as follows3-- 7a7 ,exports of rags and other paper-making material produced in the ,united ,kingdom3 tons4 l4 #ahhj4 #ee1gib #fgc1ebc #ahha4 #ej1dhh #efc1dfj #ahhb4 #di1ceb #ebf1eed #ahhc4 #ea1bic #ejb1hea #ahhd4 #fj1ibd #efb1ijc #bbb 7b7 ,exports of ditto of foreign and colonial produce3 tons4 l4 #ahhj4 #f1ife #ajb1dii #ahha4 #aj1ahc #adf1aja #ahhb4 #g1jjd #hd1eae #ahhc4 #aa1efa #aba1iib #ahhd4 #bf1dih #bgd1ffd ,the relative proportions of raw material furnished by the various countries in #ahhd 7the latest available return7 are shown in the subjoined tables3-- 7a7 ,imports of linen and cotton rags in #ahhd3 ,from ,tons4 ,germany #ba1bhj #bid1hhc ,holland #d1djf #ef1ecg ,belgium #b1hfg #cd1gac ,turkey #b1jcf #af1bbh ,france #a1hge #bh1acc ,russia #a1ghd #cc1bic ,channel ,islands #bhb #c1igb ,norway #bfa #c1cgg ,denmark #aih #c1jbj ,british ,south ,africa #acc #a1fae ,australasia #aac #b1bde ,canary ,islands #if #a1jdc ,spain #ic #a1jji ,argentine ,republic #fd #a1bhj ,other countries #gde #f1eah - #cf1bcc #dhg1hff 7b7 ,imports of esparto and other fibres in #ahhd3 ,from ,tons4 ,algeria #hh1ceg #eae1bcb ,spain #dj1aei #cad1ibg ,tripoli #cc1icj #agb1bhb ,tunis #bj1ebf #aag1cgd ,other countries #a1jcc #e1gch #ahd1jje #a1abe1eec 7c7 ,imports of other materials1 including rag and wood pulps1 in #ahhd3 #bbc ,from ,tons4 ,norway #dg1ibc #bgf1bjd ,belgium #g1afi #eh1chc ,holland #f1dhd #df1ajd ,sweden #e1agh #dh1ebc ,germany #c1gcb #cf1ehb ,france #b1abh #ad1ffg ,denmark #a1bje #ac1ccb ,british ,india #a1jdf #g1gce ,egypt #hgj #d1icc ,other countries #hjd #f1edd #gf1eci #eac1jaa ,a considerable export of raw material for paper-making also takes place from ,british shores1 the figures1 embracing rags and other materials1 for #ahhd being as below3-- 7a7 ,exports of home produced rags and other paper-making materials in #ahhd3 ,to ,tons4 ,united ,states #ei1bbb #eej1ibd ,holland #fdi #b1gjc ,british ,america #cij #d1bee ,germany #bfb #a1fgc ,other countries #dja #c1cdh #fj1ibd #efb1ijc 7b7 ,exports of foreign produced ditto in #ahhd3 7i47 ,linen and cotton rags4 ,to ,tons4 ,united ,states #ad1aia #afg1hja ,other countries #ead #e1eai #ad1gje #agc1cbj 7ii47 ,esparto and other fibres4 ,to ,tons4 ,all countries #adj #gja 7iii47 ,pulps and other materials4 ,to ,tons4 ,united ,states #aa1bij #ig1fbj ,other countries #cfc #c1jbc #aa1fec #ajj1fdc #bbd ,our imports of 8rags and other paper-making materials0 from ,norway increased from #bc1dhc tons1 value #ach1jihl41 in #ahhj1 to #dh1aii tons1 #bgi1fgil41 in #ahhd1 mainly owing to the development of the wood-pulp industry4 ,later figures will probably show a similar increment4 ,the same articles from ,denmark grew from #cei tons1 #cdjfl41 in #ahhj1 to #adjc tons1 #af1cebl41 from the same cause4 ,german statistics have even a stronger upward tendency3 #aa1ehg tons1 #aif1jeal41 in #ahhj1 against #aif1jea tons1 #cca1eial41 in #ahhd4 ,our receipts of esparto from ,algeria show an advance1 but not a marked one1 being #fj1fab tons1 #dba1cdcl41 in #ahhj1 and #hh1ceg tons1 #eae1bcbl41 in #ahhd4 ,but shipments of the same fibre from ,spain show a decline from #ea1dac tons1 #ded1gacl41 in #ahhj1 to #dj1aei tons1 #cad1ibgl41 in #ahhd2 and from ,morocco they have fallen away from #bhgi tons1 #ah1bcal41 in #ahhj1 to #bfj tons1 #abijl41 in #ahhd2 while the figures relating to ,tunis and ,tripoli also show a disposition to recede1 though not at such a rapid rate4 ,the wood-pulp industry of ,norway for the year #ahhf shows a very large increase upon the figures of a few years back1 albeit prices have ruled very low4 ,this latter circumstance is attributed1 not so much to over-production1 as to excessive competition among the sellers of this article4 ,the quantity exported during the year #ahhf is about #abj1jjj tons2 in the year #ahhe it was #ajg1fea tons2 #ahhd1 #hh1bbj tons2 #ahhc1 #gj1dfd tons2 #ahhb1 #eh1hhd tons2 #ahha1 #db1aid tons2 #ahhj1 #bf1jee tons4 ,several of the old works have extended their production during the past year1 and several new establishments are in the course of erection1 so the production this year may probably be put at #aej1jjj tons wood pulp with #ej per cent4 water4 ,the greatest part of the ,norwegian wood pulp is exported to ,england1 ,france1 and ,belgium2 in ,russia1 the increase in the duty has stopped business1 and the same can almost be said of ,germany4 ,america1 too1 has drawn part of her supply from ,norway1 but this trade is not expected to continue4 #bbe ,manufactured ,material4 ,our import trade in manufactured paper has been growing of late years1 as the following figures will show3-- ,imports of paper and pasteboard1 of all kinds except hangings3 cwt4 l4 #ahhj4 #a1jba1ieb #a1aei1fdf #ahha4 #a1jfe1iab #a1ach1idc #ahhb4 #a1jih1aah #a1bjb1ije #ahhc4 #a1afj1ajd #a1bde1hfa #ahhd4 #a1ddg1cce #a1djc1ddf ,at the same time1 our exports of manufactured paper1 though amounting to only about one-third the weight1 have very nearly as high an aggregate value as the imports1 and have increased in much the same proportion in corresponding years4 ,thus3-- ,exports of paper of all kinds but hangings3 cwt4 l4 #ahhj4 #dgb1afh #a1ajf1iif #ahha4 #eee1bai #a1bdb1ifb #ahhb4 #ehd1idg #a1cje1jbe #ahhc4 #eig1ibc #a1bhd1hfb #ahhd4 #fgj1gfj #a1cgd1cib ,the above figures relate to paper manufactured in the ,united ,kingdom4 ,in addition1 there were re-exports of paper of foreign and colonial manufacture to the following amounts3-- ,re-exports of foreign-made paper3 cwt4 l4 #ahhj4 #fh1hdc #ajh1dbf #ahha4 #fh1hfa #aja1aig #ahhb4 #ej1djc #hb1dfd #ahhc4 #di1ebf #gf1fbj #ahhd4 #ea1dfg #gh1ghe ,taking the latest year for which detailed statistics are available1 viz4 #ahhd1 we find that the importations of paper #bbf are derived from foreign states in the following proportions3-- ,imports of paper in #ahhd-- 7a7 ,writing or printing paper3 ,from ,cwt4 ,germany #ib1fha #abi1aab ,belgium #db1aci #fh1cgj ,sweden #bg1gdg #cf1fhb ,holland #bf1ejg #cd1hhd ,france #f1dfc #bh1ibe ,austria #e1cii #i1cad ,norway #d1cjj #d1gga ,other countries #c1agd #e1fee #bjh1daj #cag1gac 7b7 ,unenumerated sorts3 ,from ,cwt4 ,germany #aci1aef #bji1iaf ,sweden #aaf1dhh #abj1gic ,belgium #hb1bfc #abd1dgf ,holland #ed1eid #hd1fii ,norway #cb1bid #bf1gfe ,france #ai1cbh #fi1gfc ,united ,states #aj1ihj #ca1bja ,austria #e1ibg #ab1jab ,spain #gcf #d1jei ,japan #dba #d1gcf ,other countries #c1edg #e1iie #dfe1gcd #fid1dae 7c7 ,pasteboard and millboard3 ,from ,cwt4 ,holland #dci1gdi #bja1hid ,germany #bce1feh #aaf1ahe ,belgium #ea1bce #be1cej ,sweden #cb1cca #bj1bda ,norway #h1bfj #e1gbf ,france #c1bfb #ai1bei ,other countries #b1fif #b1ffc #ggc1aia #cia1cah ,the exports of home-made paper in the same year were distributed as follows3-- #bbg ,exports of home-made paper in #ahhd-- 7a7 ,writing1 printing1 and envelopes3 ,to ,cwt4 ,australasia #bhj1jbd #ede1hcj ,france #dd1dbg #aja1hcc ,bengal and ,burma #cc1ifc #ga1hcd ,bombay and ,scinde #bi1gfg #fd1bbg ,british ,south ,africa #af1ijj #cc1jda ,british ,north ,america #ad1hga #dd1eaa ,madras #aj1ecb #be1fea ,argentine ,republic #h1fhc #cj1ied ,united ,states #f1ihe #ca1gbb ,sweden and ,norway #f1aja #aa1hgj ,belgium #e1iha #ac1ibf ,germany #e1ifi #ad1ahh ,british ,west ,indies #d1gjf #ac1daa ,ceylon #d1ffh #aj1iai ,other countries #ca1cig #ic1ded #ejd1igc #a1ajg1cga 7b7 ,pasteboard and millboard3 ,to ,cwt4 ,australasia #ad1edb #bj1gga ,bengal and ,burma #e1adg #d1ehi ,bombay and ,scinde #d1egb #d1acd ,france #ihg #b1cji ,other countries #e1ega #ac1cfg #cj1hai #de1agj 7c7 ,unenumerated1 and articles made of paper3 ,to ,cwt4 ,australasia #fb1gca #ha1che ,british ,south ,africa #i1cda #aa1hji ,bombay and ,scinde #g1adf #aj1chi ,argentine ,republic #f1bhc #h1aac ,germany #e1adg #aa1cid ,belgium #e1abb #aa1cjj ,france #e1jeb #af1bch ,bengal and ,burma #e1jjf #f1fgh ,united ,states #d1hda #ad1ffh ,british ,america #c1gcg #g1hja ,holland #b1daj #e1ebi ,other countries #ah1aeb #cf1edg #acd1ifh #bba1hea #bbh ,the re-exports of foreign and colonial-made papers during the same period went to the following destinations3-- ,re-exports of foreign paper in #ahhd-- 7a7 ,printing and writing3 ,to ,cwt4 ,british ,india #aj1dhh #ad1fdc ,australasia #d1ijh #g1fie ,other countries #c1bcf #g1eed #ah1fcb #bi1hib 7b7 ,unenumerated3 ,to ,cwt4 ,british ,india #e1heb #g1ced ,egypt #e1afg #g1gea ,australasia #b1aca #d1cih ,russia #a1efj #g1hbi ,other countries #h1dfe #ae1hbe #bc1age #dc1aeg 7c7 ,pasteboard and millboard3 ,to ,cwt4 ,all countries #i1ffj #e1gcf #bbi ,,chapter ,,xviii4 ,,bibliography4 ,j4 ,murray4 ,practical ,remarks on ,modern ,paper4 ,edinburgh3 #ahbi4 ,l4 ,s4 ,le ,normand4 ,manuel du ,fabricant des ,papiers4 ,paris3 #ahcd4 ,g4 ,planche4 ,l',industrie de la ,papeterie4 ,paris3 #ahec4 ,l4 ,mller4 ,die ,fabrikation des ,papiers4 ,berlin3 #ahee4 ,proteaux4 ,manufacture of ,paper and ,boards4 ,philadelphia3 #ahff4 ,c4 ,hofmann4 ,manufacture of ,paper4 ,philadelphia3 #ahgc4 ,hugo ,mller4 ,pflanzenfaser4 ,leipzig3 #ahgc4 ,t4 ,routledge4 ,bamboo considered as a ,paper-making ,material4 ,london and ,new ,york3 #ahge4 ,vtillart4 tudes sur les ,fibres ,vgtales4 ,paris3 #ahgf4 ,arnot4 ,technology of the ,paper ,trade 7,cantor ,lecture1 ,society of ,arts74 ,london3 #ahgg4 ,j4 ,dunbar4 ,the ,practical ,paper-maker4 ,london3 #ahha4 #bcj ,forestry and ,forest ,products 7,edinburgh ,forestry ,exhibition74 ,edinburgh3 #ahhd4 ,c4 ,f4 ,cross and ,e4 ,j4 ,bevan4 ,cellulose4#ah ,london3 #ahhe4 ,r4 ,parkinson4 ,a ,treatise on ,paper4 ,preston3 #ahhf4 ,c4 ,t4 ,davis4 ,manufacture of ,paper4 ,philadelphia3 #ahhg4 ,tomlinson4 ,manufacture of ,paper4 ,paper-makers' ,monthly ,journal4 ,london3 since #ahgb4 ,paper ,trade ,journal4 ,new ,york3 since #ahgb4 ,papier ,zeitung4 ,berlin3 since #ahgf4 ,footnote #ah3 ,gives a list of works on ,cellulose and its derivatives4 #bca ,,chapter ,,xix4 ,,addenda4 ,the ,yaryan ,process of ,evaporation4 ,this process1 the invention of ,mr4 ,h4 ,j4 ,yaryan1 of ,toledo1 ,ohio1 ,u4,s4,a41 has been considerably developed in ,america in its several applications1 and as we have authentic information of its successful working for the recovery of soda in some of the largest paper-mills in the ,states1 we think it deserving of mention4 ,the principle of the process is that of 8multiple effects10 upon which1 indeed1 all the modern methods of economic evaporation are based4 ,the principle may be briefly explained as follows3--,a liquid is converted into vapour under ordinary conditions of boiling1 by overcoming the pressure of the atmosphere upon its surface4 ,the quantity of heat required to vaporise1 as also the temperature of the ebullition1 will be less as the pressure to be overcome is less4 ,further1 the vapour continuously driven off carries with it a quantity of heat1 which is its heat of condition or latent heat4 ,this heat it imparts to any colder body 7e4 g4 a further quantity of the same liquid7 with which it comes in contact1 direct or indirect2 if the quantity of the latter be relatively small1 it will raise its temperature approximately to that of the ebullition of the first liquid4 ,if now the pressure 7atmospheric7 on the surface of the latter be slightly reduced1 by any means1 it will boil4 ,the vapour from this can be made to boil a third quantity of the liquid1 under a further diminished pressure4 ,the successive effects in economic evaporation consist1 therefore1 in utilising the latent heat of a vapour given off from a liquid under a certain pressure 7e4 g4 that of the atmosphere7 to vaporise a further quantity of the liquid under a pressure maintained by mechanical means below that of the first4 ,in the ordinary methods the vapour does its work in the successive effects by passage through systems of tubes1 the liquid to be heated being in contact externally2 in the ,yaryan system1 on the other hand1 the arrangement #bcb is reversed4 ,the liquid to be evaporated traverses the system of tubes which are heated externally by the vapours4 ,at the end of each effect1 the liquid is caused to impinge1 in a special chamber1 upon a disc3 in this way a complete separation of liquid and vapour is effected1 each then passing on to the next effect1 the former through the tube-system1 the latter to the chamber inclosing these4 ,the flow of liquid is maintained by a force-pump1 and the diminished pressure by a vacuum-pump suitably disposed4 ,this system differs from that described on page #ahj1 in that the evaporation is continuous1 the dilute liquors entering the apparatus and the highly concentrated liquors leaving it in an unbroken stream4 ,the rate of flow is such that the evaporation of the caustic liquors from wood boiling from #h-aj to #hj ,twaddell1 in a quadruple effect1 requires only a few minutes4 ,at the latter concentration it is ready for the incineration process1 which by means of a rotary furnace1 such as that of ,mr4 ,j4 ,w4 ,hammond1 of the firm of ,s4 ,d4 ,warren and ,co41 is also effected continuously4 ,it is found1 moreover1 that the excess of heat available from this process is sufficient for the evaporation4 ,ferric ,oxide ,causticising ,process4 ,the principle of this process is the expulsion of the carbonic acid from sodium carbonate by ferric oxide at high temperatures2 this oxide playing the part of a weak acid1 entering into a loose combination with the soda1 which is overcome by water in the subsequent lixiviation process1 the ferric oxide being regenerated and a solution of caustic soda obtained4 ,the ferric oxide is therefore continuously available4 ,the main features of the process1 disregarding the question of commercial economy1 are 7#a7 that it leaves no by-products to be disposed of1 7#b7 that it enables the manufacturer to produce directly1 without evaporation1 a highly concentrated caustic lye4 ,this process has been worked out under the auspices of ,messrs4 ,brunner1 ,mond1 ,co41 and there is every reason to expect an extensive application of so simple a method4 #bcc ,,index4 ,abaca1 see ,manilla hemp ,abies pulp1 #fj ,acetic acid in bleaching1 #aad ,acid1 action on paper1 #afc in alum1 estimating1 #bjg 1 evils of1 #afc processes for wood1 #fi radicles and cellulose1 #h ,acids added in bleaching pulps1 #aab and cellulose1 #ab ,adansonia fibre1 #ec 1 boiling1 #ajc 1 cutting1 #ajc 1 willowing1 #ajc ,adipo-cellulose1 #bf ,adulterating paper1 #acj ,agalite loading1 #acc ,agave americana fibre1 #cc1 #dd ,alkali boiled with rags1 #hb process for isolating cellulose1 early methods1 #fe ,alkaline processes for isolating cellulose1 #fb ,alkalis and cellulose1 #ad and ligno-cellulose1 #ba ,aloe fibre1 #cc1 #ci1 #dd1 #df 1 dimensions1 #ci perfoliata fibre1 #ci ,alum1 action on cellulose1 #afc 1 on gelatine1 #afc 1 analysing1 #bjf cake1 analysing1 #bjf 1 estimating acid in1 #bjg 1 freedom from acid1 #afc in sizing1 #aci 1 proportion required1 #ada solutions1 table of strengths1 #adc ,alumina resinate1 #acg ,alumina sulphate1 analysing1 #bjf in sizing1 #adj ,aluminous cake1 #adj ,ammoniacal solution of cupric oxide1 #e ,amyloid1 #ab ,analysis of plant substances1 #db ,analysing alum1 #bjf cake1 #bjf alumina sulphate1 #bjf antichlor1 #bjh bleaching powder1 #bje caustic soda1 #bje dyes1 #bji gelatine1 #bjh loading material1 #bjc1 #bji paper1 #aii pigments1 #bji recovered soda1 #bje size1 #bjc soaps1 #bjh soda ash1 #bje sodium sulphite1 #bjh thiosulphate1 #bjh starches1 #bjh wood pulp1 #bja ,ananassa sativa fibre1 #dd ,aniline blues1 #ada colours1 solutions1 #cg for diagnosing plant substances1 #dc pinks1 #adb sulphate solution1 #cg ,animal cellulose1 #g ,annandale's damping method1 #aei ,antichlor1 analysing1 #bjh 1 lime and sulphur1 #abi 1 proportion required to neutralise bleaching powder1 #abh 1 removing bleaching liquor by1 #abg ,antichlor1 sodium hyposulphite1 #abg1 #abi 1 sulphite1 #abe 1 thiosulphate1 #abg1 #abi 1 testing1 #acj ,apparatus for microscopic examination of fibres1 #ce ,ash of cotton pulp1 #acf of esparto pulp1 #acf of linen pulp1 #acf of paper1 estimating1 #acd of paper1 natural1 #acf of straw pulp1 #acf of wood pulp1 #acf ,aspen for mechanical wood pulp1 #ajh ,available chlorine in bleaching powder1 #aaj ,bachet and ,machard's process forwood1 #fi ,baobab fibre1 #ec composition1 #ed ,barium hydrate and cellulose1 #g ,bark fibres1 #b ,barley straw1 #ih ,barre's acid process for wood1 #fi ,bast fibres1 #cd 1 dimensions1 #ci filaments1 #cd 1 nature of1 #b tissues1 #ec ,beater bed-plate1 #abj knives1 #abj 1 cutting in situ1 #aba 1 lead-lined1 #abj ,beaters1 #aag 1 direct-driven1 #abf 1 engine for driving1 #abf 1 water for1 #abe ,beating esparto1 #aag 1 proportion of water to pulp1 #aah pulp1 #aag 1 duration of1 #aai wood pulp1 #aag ,bed-plate of beater1 #abj ,beech1 composition1 #fa ,bertram's beater1 #abb damping cylinder1 #aei direct-driven beaters1 #abf ,bertram's rag boiler1 #hb smoothers1 #aeh strainers1 #adh ,bibliography1 #bbi ,birch1 composition1 #fa 1 pulp yield1 #gg ,bisulphite1 action on cellulose compared with soda1 #gf 1 colour of pulp produced by1 #gg process1 advantages1 #gf processes for wood1 #ga ,bleached pulp1 freeing from bleach1 #aad 1 improving colour1 #aad ,bleaching1 acetic acid in1 #aad action should be confined to non-cellulose1 #aac by chlorine1 #aad 1 electrolytic1 #aae pulp in potchers1 #aaa pulps1 #aaj rags1 #aae refractory pulps1 #aad 1 time required by1 #aac 1 with sodium hypochlorite1 #aac ,bleaching-liquor1 clear1 #aaa 1 removing by antichlor1 #abg 1 removing from half-stuff1 #abg 1 storing1 #aaa 1 strength1 #aaa 1 washing out from half-stuff1 #abg ,bleaching-powder1 accelerating action of1 #aab 1 analysing1 #bje and cellulose1 #aj 1 available chlorine in1 #aaj 1 keeping1 #aaa 1 neutralising by lime and sulphur1 #abi 1 by sodium hyposulphite1 #abg1 #abi 1 by sodium sulphate1 #abh 1 by sodium thiosulphate1 #abg1 #abi 1 preparing1 #aaj 1 proportion of antichlor required to neutralise1 #abh 1 quantities needed1 #aab ,blitz's sulphide process1 #fg ,blondel's acid process for wood1 #fi ,blotting paper1 starching1 #aci ,blue colours1 #ada ,boehmeria1 #ej nivea fibre1 #ci puya fibre1 #dd ,boilers for esparto1 #ij for resolving wood1 #gd for straw1 #ii 1 iron1 #gf 1 lead-lining1 #ge ,boiling adansonia fibre1 #ajc esparto1 #hi1 #ia jute1 #ajc manilla hemp1 #ajc rags1 #hb straw1 #ajj ,boiling-liquors1 recovering soda from1 #agi ,bombax heptaphyllum fibre1 #ci ,books on paper-making1 #bbi ,bottoms1 caustic1 #agg ,broke paper1 grinding mill1 #aje 1 using up1 #ajd ,bromine and jute1 #ah ,broussonetia kmpferia fibre1 #ed papyrifera fibre1 #ci1 #ed ,burning recovered soda1 #ahf ,calcining recovered soda1 #ahf ,calendering1 #afg ,calenders1 #aeh 1 deflection1 #aga ,calcium carbonate mud1 #aij hypochlorite1 removing from pulp1 #aad sulphate1 estimating1 #bjc loading1 #aca ,cannabis sativa fibre1 #ci1 #di ,carbonic acid bleaching1 #aae ,carbonising recovered soda1 #ahf ,caustic soda1 analysing1 #bje 1 brands1 #agh 1 commercial forms1 #agg drums1 emptying1 #agi 1 prices1 #agi solutions1 table of strengths1 #aji ,causticisers1 #ahh1 #aib ,causticising1 #ahg by ferric oxide1 #bcb 1 lime used1 #aij 1 oxygenating during1 #aia ,cellular tissue in straw1 #ajc ,cellulose1 #d 1 absorption of acids and basic oxides1 #g 1 action of alum on1 #afc 1 of cuprammonium on1 #e1 #bag 1 of lime on1 #hd 1 of soda and bisulphite compared1 #gf 1 of sulphur on1 #acj 1 on light1 #f and acids1 #ab and alkalis1 #ad and barium hydrate1 #g and bleaching powder1 #aj and chlorine1 #aj and humus1 #ae and hydrochloric acid1 #ac and lead solutions1 #h and metallic salts1 #h and nitric acid1 #ac and oxygen1 #aj and sulphuric acid1 #ab and water at high temperature1 #ad and zinc chloride1 #ac 1 animal1 #g 1 behaviour under ,schweitzer's reagent1 #e 1 bleaching should not affect1 #aac 1 burning1 #bc 1 characters1 #d 1 combinations1 #g 1 with acid radicles1 #h compared with jute1 #ag 1 composition1 #d 1 compounds1 #g1 #af 1 decomposition1 #ab 1 by ferments1 #ae 1 by heat1 #bc 1 destructive action of soda on1 #fd di-nitrate1 #aj 1 early form of alkali process for isolating1 #fe formed by vinegar plant1 #af 1 formula1 #d gelatinised1 #e 1 general method of isolation1 #d hexa-nitrate1 #i 1 identification1 #f1 #ah ,cellulose in contact with iron1 #ac in fibre1 estimating1 #db in straw1 #ii 1 isolating by sulphurous acid1 #fd 1 from plant substances1 #fb 1 from wood1 ,schultze's method1 #ba 1 lignification1 #ag 1 mineral constituents1 #e 1 modifications of1 in the plant1 #af 1 nitration of1 #h 1 oxidation1 #aj 1 penta-nitrate1 #i 1 percentage yielded by jute1 #ai 1 proportion in esparto1 #if 1 of1 in well-boiled pulp1 #aac 1 reactions1 #f 1 soluble in ,schweitzer's reagent1 #e 1 sulphides for isolating1 #fg 1 solubility1 #e 1 synthesis1 #ae 1 tetra-nitrate1 #aj 1 triacetyl1 #h 1 tri-nitrate1 #aj 1 yield from esparto1 #ie 1 from straw1 #ih ,celluloses1 compound1 hydrolytic resolution1 #fc 1 1 treating for paper1 #fc ,cellulosic fermentation1 #af ,chapman's evaporator1 #ahd ,chemical analysis of plant substances1 #db examination of paper1 #bja ,chestnut1 pulp yield1 #gg ,china clay1 estimating1 #bjc loading1 #aca grass1 #ci1 #df1 #ej 1 character1 #ej 1 composition1 #ea fibres1 dimensions1 #ci 1 forms in which employed1 #ea 1 general chemical characteristics1 #ea 1 micro-chemical reaction1 #ea 1 microscopic features1 #ea ,chlorinating straw pulp1 #ajb ,chlorinating wood tissue1 #ai ,chlorine and cellulose1 #aj and jute1 #ah as a bleaching agent1 #aad 1 available1 in bleaching powder1 #aaj water solution1 #cg ,clarifying water1 #abe ,classification of paper as to strength1 #aig ,cleaning straw1 #ajj ,closing plates of strainers1 #aej ,cochineal lakes1 #adb ,collodion pyroxyline1 #aj ,colophony1 #acg ,colour1 improving1 #aad of pulp produced by bisulphite1 #gg ,colouring paper1 #ada ,commercial statistics1 #bba ,composition of paper1 testing1 #aii ,compound celluloses1 hydrolytic resolution1 #fc 1 treating for paper1 #fc ,conifer pulp1 #fj ,constitution of plant fibres1 #a ,cooke and ,hibbert's beater1 #abc ,corchorus capsularis fibre1 #ci1 #dd1 #eb olitorius fibre1 #ci ,cork1 #bf ,cotton1 #df 1 classification1 #df 1 composition of raw fibre1 #dg fibres1 dimensions1 #ci 1 forms in which employed1 #dh 1 general chemical characteristic1 #dg in paper1 detecting1 #aii1 #bja 1 micro-chemical reaction1 #dg 1 microscopic features1 #df 1 nature of1 #a pulp1 ash1 #acf 1 beaten1 #aah 1 dimensions of fibre1 #aai rags1 statistics1 #bba1 #bbb 1 treatment for paper1 #gi sections1 #dg ,couch rolls1 #aef ,cream caustic1 #agg ,cross's boiler1 #gf ,crotalaria juncea fibre1 #dd1 #ej ,crystal carbonate1 #ach ,cuprammonium1 #bag ,cuprammonium solution1 preparing1 #bag ,cuticular tissue1 #bf ,cutting1 #aga adansonia fibre1 #ajc beater knives1 #aba jute1 #ajc manilla hemp1 #ajc rags1 #ha straw1 #ajj ,dahl's sulphide process1 #fg ,damping-cylinders1 #aei ,dandy roll1 #aee ,dark paper from jute1 #ajc ,deckle1 #add1 #aeb ,densities1 ,twaddle1 and sp4 gr41 #aji ,detecting adulteration1 #bjc ,diagnosis of plant substances1 #db ,dicotyledonous stems1 fibres of1 #cc1 #df ,direct-driven beaters1 #abf ,discoloration of paper from mechanical wood pulp1 #ajh ,doctor1 #aeg ,draining bleached pulp1 #aad boiled rags1 #hd straw pulp1 #ajj ,drum washer for boiled rags1 #he ,dry pulp1 preparing1 #aai ,drying cylinders1 #aeg ,dusting rags1 #hb ,dyes1 #ada 1 analysing1 #bji ,economy of sulphide processes1 #fh ,edgerunner mill1 #aai ,edgworthia papyrifera fibre1 #ed ,ekman's bisulphite process1 #gb process1 preparing wood for1 #gc ,electrolytic bleaching1 #aae ,emptying soda drums1 #agi ,engine for driving beaters1 #abf sizing1 #acg ,esparto1 #df1 #ee 1 amount of bleaching powder needed by1 #aab 1 beating1 #aag 1 boiled1 washing1 #ie boiler1 ,roeckner's1 #ic 1 ,sinclair's1 #id 1 boiling1 #hi1 #ia 1 character1 #ee 1 cleaning machine1 #ij 1 composition1 #eg fibres1 dimensions1 #ci 1 general chemical characteristics1 #ef in paper1 detecting1 #aii1 #bja liquor1 disposal of1 #ih 1 micro-chemical reaction1 #ef 1 microscopic features1 #ef paper mill1 arrangement1 #baj 1 picking1 #ij 1 presse-pte system1 #if 1 pressure for boiling1 #ic 1 proportion of cellulose in1 #if pulp1 ash1 #acf 1 dimensions of fibre1 #aai 1 quantity of soda for1 #ib section1 #ef 1 soda required by1 #hi 1 statistics1 #bba1 #bbb 1 substances removed from1 by caustic soda1 #ig 1 time of boiling1 #ib 1 treating for paper1 #fc 1 yield of cellulose1 #ie ,estimating acid in alum1 #bjg added mineral matter in paper1 #acf mineral matter in paper1 #acd ,evaporating soda liquors1 #ahj1 #bca ,evaporators1 #ahj1 #bca 1 ,chapman's1 #ahd 1 ,roeckner's1 #aha 1 ,porion's1 #ahb 1 smell consumer1 #ahc 1 ,yaryan1 #bca ,felting1 #ca caused in potchers1 #aac ,fermentation1 cellulosic1 #af ,ferments decomposing cellulose1 #ae ,ferric oxide causticising process1 #bcb ,fibre bundles1 #cd 1 interweaving to form paper1 #cj 1 theoretical value in paper1 #cj ,fibres1 analysis1 complete1 #dc and cells1 #a 1 apparatus for microscopic examination1 #ce classified according to iodine reaction1 #df 1 dimensions1 #ch 1 in pulps1 #aai 1 estimating cellulose in1 #db 1 purity1 #ci 1 isolating for examination1 #ch 1 microscopic features1 #cb 1 nature of1 #a of dicotyledonous stems1 #cc of monocotyledonous stems1 #cc 1 physical structure1 #cj 1 raw1 analysing1 #db 1 reagents for examining1 #cf 1 sections for examination1 #ch 1 separation1 #cd 1 table of characters1 #dd 1 of length1 #ci 1 ,webster on analysis of1 #db ,fibrous tissue1 #cd ,fibro-vascular bundles1 #b 1 dimensions1 #ci ,filaments1 #cd 1 dimensions of cells and fibres1 #ci 1 table of lengths1 #ci ,filter bags for water1 #abf paper1 starching1 #aci ,filtering lime mud1 #aij ,finish1 #aei ,finishing-house1 #age ,fir pulp1 #fa ,flax1 #ci1 #dd 1 characters1 #dh 1 composition of raw fibre1 #dh fibres1 dimensions1 #ci 1 forms in which employed1 #di 1 general chemical characteristic1 #dh 1 micro-chemical reaction1 #dh 1 microscopic features1 #dh sections1 #dh ,forbes' beater1 #abb ,fourdrinier machine1 #ade ,francke's bisulphite process1 #gb ,friction-glazing1 #afi ,fry1 ,ransome1 and ,wilkie's wood-splitting machine1 #gd ,furfural1 #ba ,gaskell and ,deacon's crystal carbonate1 #ach sodium sulphite1 #abh ,gelatine1 action of alum on1 #afc 1 analysing1 #bjh 1 estimating amount of1 #bjd for sizing1 #afa1 #afb size1 making1 #afb with soap1 #afc ,glaser's straw pulp chlorinating process1 #ajb ,glazing1 #afg 1 influence on strength1 #aih ,gossypium fibres1 #ci1 #df ,gould's beater1 #abb ,greenbank soda1 #agh ,grinding straw pulp1 #aja wood to pulp1 #aje ,guillotine cutter1 #agd ,gun-cotton1 #i ,half-stuff defined1 #hh 1 freeing from bleaching liquor1 #abg 1 removing bleaching liquor from1 by antichlor1 #abg 1 washing out bleaching liquor from1 #abg ,hand-made paper1 #add ,hartig-,reusch paper-testing machine1 #aid ,hemp1 #ci1 #df1 #di 1 characters1 #di 1 composition1 #ej fibres1 dimensions1 #ci 1 forms in which employed1 #ej 1 general chemical characteristic1 #ej 1 micro-chemical reaction1 #ej 1 microscopic features1 #di 1 section1 #ej ,hermite's electrolytic bleaching1 #aae ,hibiscus strictus fibre1 #dd1 #df ,humus and cellulose1 #ae ,hydracellulose1 #ab ,hydrochloric acid and cellulose1 #ac ligno-cellulose1 #bb in bleaching pulps1 #aab ,hydrolytic resolution of compound celluloses1 #fc ,igniting recovered soda1 #ahf ,iodine and jute1 #ag lignified tissue1 #ag starch paper1 making1 #acj reaction1 details of manipulation1 #dj solution1 #cf 1 testing1 #cf ,iron boilers1 #gf oxide causticising process1 #bcb ,jolly's balance1 #ace ,jordan beater1 #aba ,jute1 #cc1 #ci1 #dd1 #df1 #eb and bromine1 #ah chlorine1 #ah iodine1 #ag 1 boiling1 #ajc 1 character1 #eb compared with cellulose1 #ag 1 cutting1 #ajc 1 dark paper from1 #ajc fibres1 dimensions1 #ci 1 forms in which employed1 #ec 1 general chemical characteristic1 #ec 1 micro-chemical reactions1 #eb 1 microscopic features1 #eb 1 objection to acid in bleaching1 #aab 1 reactions1 #ag 1 treating for paper1 #fd 1 willowing1 #ajc ,kaolin1 estimating1 #bjc 1 loading1 #aca ,kingsland beater1 #aba ,knives for cutters1 #aga of beater1 #abj 1 cutting in situ1 #aba ,knotter1 #aea ,laid paper1 #aef ,lead lining to beater1 #abj solutions and cellulose1 #h ,leaden boilers1 #ge ,leaf fibres1 #b ,lignification estimated by aniline1 #dc of cellulose1 #ag ,lignified tissue and chlorine1 #ah iodine1 #ag ,ligno-cellulose1 #bj 1 aldehydic character1 #be 1 and dilute alkalis1 #ba and dilute mineral acids1 #bj and hot water1 #ba and hydrochloric acid1 #bb and mineral acids1 #bj and nitro-sulphuric acid1 #bb and sulphuric acid1 #bb 1 animal digestion of1 #bc 1 decay of1 #bc 1 decomposition by heat1 #bc 1 distribution1 #bc 1 treating for paper1 #fd ,lime1 action on cellulose1 #hd and sulphur for neutralising bleaching powder1 #abi boiled with rags1 #hc for causticising1 #aij 1 milk of1 #agg mud1 #aij 1 composition1 #aia 1 filtering1 #aij salts in water1 #bab sulphate loading1 #aca unsuited for esparto1 #hi ,lime-tree1 composition1 #fa ,linden bast fibres1 #ci1 #ed ,linen1 #df in paper1 detecting1 #aii1 #bja pulp1 ash1 #acf 1 beaten1 #aag 1 dimensions of fibre1 #aai rags1 statistics1 #bba1 #bbb 1 treatment for paper1 #gi ,linum usitatissimum fibre1 #ci1 #dd1 #df ,literature1 #bbi ,loading1 estimating1 #acd materials1 analysing1 #bji paper1 #acj with agalite1 #acc with china clay1 #aca with lime sulphate1 #aca with magnesium silicate1 #acd with pearl-hardening1 #aca ,loft-dried paper1 #ade ,lunge's bleaching method1 #aad ,lygeum spartum fibre1 #ee ,machine1 #ade ,magnesium silicate loading1 #acd ,manilla hemp1 #dd1 #df1 #ei 1 boiling1 #ajc 1 composition1 #fj 1 cutting1 #ajc 1 micro-chemical reaction1 #fj 1 microscopic features1 #ei 1 sections1 #fj 1 treating for paper1 #fd 1 willowing1 #ajc ,masson1 ,scott1 and ,bertram's beater1 #abc esparto-cleaning machine1 #ij strainer1 #adi ,mechanical wood pulp1 #aje 1 quantitative estimation1 #bjb ,menzies and ,davis' smell consumer1 #ahc ,metallic salts and cellulose1 #h ,microscope equipment1 #ce ,microscopic features of fibres1 #cb ,microscopical examination of paper1 #bja ,milk of lime1 #agg ,mill1 arrangement1 #baj 1 site for1 #baj ,millboard machine1 #aff ,mineral acids and cellulose1 #bj and ligno-cellulose1 #bj matter1 added1 estimating1 #acf in paper1 estimating1 #acd ,mixing pulps1 #aai ,monocotyledonous stems1 fibres of1 #cc1 #df1 #ed ,mounting solution1 #cf ,musa paradisiaca fibre1 #dd textilis1 #ei ,names in paper1 #ade1 #aef ,nettle1 #eb ,neutral mounting solution1 #cf ,new ,zealand flax1 #ci1 #dd1 #df1 #ei 1 dimensions1 #ci general chemical characteristics1 #ei micro-chemical reaction1 #ei ,new ,zealand flax1 microscopic features1 #ei ,nilgherry nettle1 #dd ,nitric acid and cellulose1 #h1 #ac ,nitro-sulphuric acid and ligno-cellulose1 #bb ,oak1 pulp yield1 #gg ,oat straw1 #ih ,oxidising sodium sulphide1 #aia ,oxycellulose1 #ac ,oxygen and cellulose1 #aj ,oxygenating liquors while causticising1 #aia ,paper ash1 estimating1 #acd 1 broke1 pulp from1 #ajd 1 colouring1 #ada from mechanical wood pulp1 faults of1 #ajh 1 hand-made1 #add 1 loading1 #acj 1 loft-dried1 #ade machine1 #ade makers' soap1 #afc making and textiles1 #c 1 measuring strength1 #aic 1 natural ash1 #acf 1 printed1 pulp from1 #aje 1 sources of raw material1 #a 1 thickness1 #aec 1 toned1 #adb trade1 statistics1 #bbe waste1 pulp from1 #ajd 1 width1 #aeb ,paper-mulberry fibres1 #ci1 #df1 #ed ,partington's bisulphite process1 #gb ,patterns on paper1 #ade1 #aef ,pearl hardening1 #aca 1 estimating1 #bjc ,pectic acid1 #bh ,pecto-cellulose1 #bh 1 treating for paper1 #fc ,phormium tenax fibre1 #ci1 #dd1 #ei ,physical structure of fibres1 #cj ,picking esparto1 #ij ,pictet's sulphurous acid process1 #gj ,pigments1 #ada 1 analysing1 #bji ,pine1 composition1 #fa 1 pulp yield1 #gg ,pine1 white1 for mechanical wood pulp1 #ajh wood fibre1 #fa ,pineapple fibre1 #dd1 #df ,pink colours1 #ada ,pinus fibre1 #fj ,plant fibres1 constitution1 #a 1 structural elements1 #a tissues mainly cellulose1 #d ,pochin's aluminous cake1 #adj ,poplar1 composition1 #fa fibre1 #fj ,porion's evaporator1 #ahb ,porter-,clark process for water1 #bad ,potchers1 felting caused in1 #aac for bleaching pulp in1 #aaa for rags1 #hj ,presse-pte system for esparto1 #if for straw1 #aja ,pressure for boiling straw1 #ajj in relation to soda1 #fd ,prussian blue1 #adb ,pulp1 beating1 #aag 1 bleaching1 #aaj 1 refractory1 #aad 1 colour of1 produced by bisulphite1 #gg 1 dimensions of fibre in1 #aai 1 dry1 preparing1 #aai 1 duration of beating1 #aai 1 freeing from bleach1 #aad 1 improving colour1 #aad 1 mixing1 #aai 1 removing calcium hypochlorite from1 #aad1 #abg saver1 #aad1 #aee yield from straw1 #ii woods1 #gg ,purification of water1 #baa ,rags1 bleaching1 #aae 1 boiled1 draining1 #hd 1 1 washing1 #he 1 boiling1 #hb 1 with lime1 #hc 1 cutting1 #ha 1 dusting1 #hb 1 potchers1 #hi 1 proportion of alkali1 #hc 1 quantity of water for boiling1 #hd 1 sorting1 #hj 1 statistics1 #bba1 #bbb 1 time of boiling1 #hd 1 treatment for paper1 #gi 1 in washer1 #hi 1 willowing1 #ha ,ramie fibres1 dimensions1 #ci1 #ej ,raw material for paper1 #a ,reagents for examining fibres1 #cf ,recovered soda1 analysing1 #bje 1 carbonising1 #ahf causticising1 #ahg 1 composition1 #ahf ,refractory pulps1 bleaching1 #aad ,repped paper1 #aga ,resinate of alumina1 #acg ,retree1 #age ,rhea fibre1 #ej ,roeckner's esparto boiler1 #ic evaporator1 #aha strainer1 #aej water clarifier1 #baa ,rosin1 #acg soap1 #acg ,rotary boilers unsuited to esparto1 #ij ,rubbing test for paper1 #aig ,rye straw1 #ih ,salle1 #age ,salmon's guillotine1 #agd ,save-all1 #aed ,schultze's method of isolating cellulose from wood1 #ba ,schurmann's calender rolls1 #aga ,schweizer's reagent1 #e ,sections of fibres for examination1 #ch ,seed hairs1 #df 1 dimensions1 #ci ,self-cleaning strainer1 #adi ,settling ponds1 #abe ,seventy per cent4 white caustic1 #agh ,sheave1 causes of1 #ij ,silk fibre1 #ca ,sinclair's esparto boiler1 #id ,single cylinder machines1 #afd sheet cutter1 #agc ,siphon washer for boiled rags1 #hg ,site for mill1 #baj ,sixty per cent4 white caustic1 #agg ,size1 estimating amount of1 #bjd 1 nature of1 #bjc 1 making with gelatine1 #afb ,sizes of sheets1 #age ,sizing1 #acg ,slicer1 #aea ,smalts1 #ada ,smell consumer1 #ahc ,smoothers1 #aeh ,smoothness1 #aei ,soaking wood1 #ajg ,soap1 analysing1 #bjh and gelatine1 #afc for paper-makers1 #afc ,soda1 action on cellulose compared with bisulphite1 #gf ash1 analysing1 #bje bicarbonate for accelerating action of bleaching powder1 #aab 1 brands1 #agh carbonate for sizing1 #ach 1 commercial kinds1 #agg 1 destructive action on cellulose1 #fd drums1 emptying1 #agi for esparto1 #hi for isolating cellulose1 #fc in relation to pressure1 #fd liquor from esparto1 treatment of1 #ih 1 evaporating1 #ahj1 #bca 1 removing sodium-sulphur compounds1 #aia 1 prices1 #agi 1 proportion for straw1 #ii 1 recovered1 analysing1 #bje 1 carbonising1 #ahf 1 causticising1 #ahg 1 composition1 #ahf recovery1 #agi solutions1 table of strengths1 #aji 1 substances removed from esparto by1 #ig ,sodium hypochlorite in bleaching1 #aac hyposulphite1 analysing1 #bjh for neutralising bleaching powder1 #abg1 #abi sulphide1 oxidising1 #aia sulphite1 analysing1 #bjh to neutralise bleaching powder1 #abh -sulphur compounds in soda liquors1 #aia thiosulphate1 analysing1 #bjh thiosulphate for neutralising bleaching powder1 #abg1 #abi ,soft water1 objections to1 #baf ,soluble sulphides for isolating cellulose1 #fg ,solutions1 alum1 table of strengths1 #adc 1 aniline colours1 #cg 1 aniline sulphate1 #cg 1 chlorine water1 #cg 1 iodine1 #cf 1 neutral mounting1 #cf ,sorting1 #age rags1 #hj ,specific gravity1 ,twaddle converted into1 #aji ,spherical rag boiler1 #hb ,stanhope purifier1 #bab1 #bad ,starch and iodide paper1 making1 #acj 1 estimating1 #bjc paste for sizing1 #ach ,starches1 analysing1 #bjh ,starching blotting paper1 #aci filter paper1 #aci ,statistics1 #bba ,steam and ligno-celluloses1 #ba ,steaming wood1 #ajg ,stipa tenacissima fibre1 #ci1 #ee ,strainers1 #adg 1 closing plates1 #aej 1 knotter1 #aea ,straw1 #df1 #eg 1 amount of bleaching powder needed by1 #aab 1 boiled1 washing1 #ajj 1 boilers for1 #ii 1 boiling1 #ajj 1 cellulose yield from1 #ih 1 cleaning1 #ajj 1 composition1 #ei1 #ii 1 cutting1 #ajj 1 dimensions of cells1 #eh 1 general chemical characteristics1 #eh in paper1 detecting1 #bjj1 #bja 1 microscopic features1 #eg paper1 source of weakness1 #ajc 1 pressure in boiling1 #ajj 1 proportion of soda for1 #ii pulp1 ash1 #acf 1 chlorinating1 #ajb 1 dimensions of fibre1 #aai pulp1 draining1 #ajj 1 dry1 preparing1 #aai 1 grinding1 #aja 1 yield1 #ii 1 soda treatment1 #ih 1 treating for paper1 #fc washer1 #aja ,strengths of alum solutions1 table1 #adc of paper1 classification1 #aig 1 influence of glazing1 #aih 1 measuring1 #aic ,sugar-cane fibre1 #ei ,sulphide processes1 economy of1 #fh 1 malodours of1 #fh ,sulphite processes1 objection to1 #ge ,sulphur1 action on cellulose1 #acj and lime for neutralising bleaching powder1 #abi ,sulphuric acid and cellulose1 #ab and ligno-cellulose1 #bb in bleaching pulps1 #aab ,sulphurous acid for isolating cellulose1 #fd processes for wood1 #gj processes1 objection to1 #ge ,sunda1 see ,sunn hemp4 ,sunn hemp1 #dd1 #df1 #ej 1 characters1 #ej 1 composition1 #ej 1 general chemical characteristics1 #ej 1 micro-chemical reactions1 #ej 1 microscopic features1 #ej ,synthesis of cellulose1 #ae ,table of processes for resolving wood1 #gh of strengths of alum solutions1 #adc of caustic soda solutions1 #aji ,teazing needles1 #ch ,telegram paper1 #ajd ,test paper1 making1 #acj ,testing antichlor1 #acj iodine solution1 #cf paper1 #aic by rubbing1 #aig ,textile trade waste1 treating for paper1 #fb ,thickness of paper1 gauging1 #aec 1 measuring1 #aih ,thompson's rag-bleaching process1 #aae ,thune's mechanical wood pulp1 #ajg ,tilghmann's sulphurous acid process1 #gj ,tilia grandifolia fibre1 #ci1 #ed ,time of boiling rags1 #hd ,toned paper1 #adb ,trade statistics1 #bba ,triacetyl cellulose1 #h ,tub sizing1 #acg on the machine1 #afj ,twaddle degrees1 converting into specific gravity1 #aji ,ultramarine1 #ada ,umpherstoil's beater1 #abc ,urtica dioica fibre1 #eb heterophylla fibre1 #dd ,vacuum strainer1 #adh ,victory cutter1 #agd ,vinegar plant forming cellulose1 #af ,vomiting boiler1 #ia ,washing boiled esparto1 #ie rags1 #he straw1 #ajj out bleaching liquor from half-stuff1 #abg ,waste paper1 pulp from1 #ajd ,water and ligno-cellulose1 #ba at high temperature and cellulose1 #ae 1 clarifier1 #baa 1 clarifying1 #abe 1 filter bags1 #abf for beaters1 #abe 1 lime salts1 #bab marks1 #ade1 #aef 1 ,porter-,clark process1 #bad proportion to pulp in beating1 #aah 1 purification1 #baa 1 quantity for boiling rags1 #hd resolving wood by1 #fe 1 settling ponds1 #abe 1 soft1 objections to1 #baf 1 soluble impurities1 #bab ,water supply1 #baj ,web glazing1 #afg ,webster on analysis of fibres1 #db ,weighing paper ash1 #acd ,weight per ream1 #agf ,weighting paper1 #acj ,wet end of machine1 #aed felt1 #aeg ,wheat straw1 #ih ,white fir fibre1 #fa pine for mechanical wood pulp1 #ajh ,width of paper1 gauging1 #aeb ,willesden canvas1 #bai paper1 #bai scrim1 #bai welded goods1 #bbj ,willowing adansonia fibre1 #ajc jute1 #ajc ,manilla hemp1 #ajc rags1 #ha ,winding1 #afj ,wire-cloth1 #aec in rag washer1 #hg 1 shifting1 #aef ,wood1 acid processes1 #fi 1 amount of bleaching powder needed by1 #aab 1 bisulphite processes1 #ga 1 boiling with sulphites1 #gd 1 chemical1 in paper1 detecting1 #bjj 1 cutting up for pulp1 #aje 1 grinding1 #aje 1 mechanical1 in paper1 detecting1 #bjj1 #bja 1 objection to acid in bleaching1 #aab processes1 table of1 #gh pulps1 #fj 1 ash1 #acf beating1 #aag 1 dimensions of fibre1 #aai 1 dry1 preparing1 #aai from aspen1 #ajh from white pine1 #ajh 1 mechanical1 #aje 1 1 quantitative estimation1 #bjb 1 statistics1 #bbd 1 resolving by water1 #fe 1 ,schultze's method of isolating cellulose from1 #ba 1 soaking1 #ajg splitting machine1 #gd 1 steaming1 #ajg suitable for ,ekman's process1 #gc 1 sulphide treatment1 #fg 1 sulphurous acid processes1 #gj 1 treating for paper1 #fd ,woods1 pulp yield of1 #gg ,wool fibre1 character1 #ca ,wove paper1 #aef ,wrapping paper1 #ajd ,yankee machine1 #afd ,yaryan evaporator1 #bcb ,young and ,pettigrew's acid process1 #fi ,yucca gloriosa fibre1 #dd1 #df ,zinc chloride and cellulose1 #ac ,,london3 ,,printed ,,by ,,wm4 ,,clowes ,,and ,,sons1 ,,limited1 ,,stamford ,,street ,,and ,,charing ,,cross4 ,,advertisements4 advertisement ,,geo4 ,,wm4 ,,bertram1 ,,makers ,,of ,,every ,,description ,,of ,,machinery ,,in ,,connection ,,with ,,the ,,manufacture ,,of ,,paper4 ,,st4 ,,katherine',s ,,works1 ,,sciennes1 ,,edinburgh1 ,,and ,,london4 ,illustration3 ,gold and ,silver ,medals1 ,edinburgh ,international ,exhibition1 #ahhf4 ,illustration3 ,first-class ,medal1 ,london ,international ,exhibition1 #ahfb4 ,,specialties4 ,improved ,paper ,making ,machines 7nearly #ajj at work74 ,presse ,pte ,machines4 ,single ,cylinder ,machines4 ,patent ,flat ,strainers 7over #bjj at work74 ,special ,strainer ,plates4 ,kollergangs or ,edge ,runners4 ,angle and ,square ,paper ,cutters4 ,slitting and ,winding ,machines4 ,web ,glazing ,calenders4 ,superior ,chilled ,rolls4 ,patent ,cone ,beater4 ,sheet and ,boarding ,calenders4 ,improved ,damping ,rolls4 ,patent ,deckle for ,wire ,frames 7,archibald and ,purdie's74 ,patent ,wire ,guide4 ,improved ,pulp ,engines4 ,direct ,driving ,gear for ,pulp ,engines4 ,pumps of ,all ,kinds4 ,hydraulic ,presses and ,hoists4 ,,also ,steam ,engines of all ,classes1 ,high-pressure4 ,condensing1 or ,compound1 up to any indicated ,horse-power1 ,over #cjj at work4 _/advertisement advertisement ,,bentley ,,jackson1 ,,paper-,,makers' ,,engineers1 ,,bury1 ,,near ,,manchester1 ,makers of ,rag ,choppers1 ,dusters ,willows4 ,patent ,rag ,cutter1 ,to ,cut ,rags or ,bagging into pieces #a inch square and upwards4 ,spherical ,cylindrical ,revolving ,rag ,boilers4 ,improved ,rag ,engines4 ,paper-,cutting ,machines4 ,ripping ,winding ,machines4 ,presse ,ptes4 ,paper-,making ,machines4 ,steam ,engines4 ,illustration3 ,,edge ,,runner4 ,,machine-,,made ,,wheels ,,and ,,pulleys4 ,,estimates ,,on ,,application4 _/advertisement advertisement ,mc,dougall's ,patent ,steam ,trap1 ,,specially ,,adapted ,,for ,,paper-,,makers4 ,for ejecting automatically1 without loss of steam1 the water of condensation from drying cylinders1 calender rolls1 steam-engine cylinders1 steam piping1 c41 c4 ,will work at zero1 or #bej lb4 pressure4 ,all working parts are of gun-metal4 ,the only trap made on a correct principle4 ,illustration ,for ,prices and further information apply to ,,the ,,chadderton ,,iron ,,works ,,co41 ,,limited1 ,,engineers1 ,,boiler ,,makers1 ,,and ,,ironfounders1 ,,irk ,,vale1 ,,chadderton1 ,near ,,manchester1 ,sole ,makers of ,plant for ,mc,dougall's ,patent ,wood ,pulp ,process4 ,specialty1 ,revolving ,boilers1 #h to #ab feet diameter4 ,,london ,,office--#aj ,,mark ,,lane4 ,,manchester ,,office--#fh1 ,,port ,,st4 _/advertisement advertisement ,published on the #ajth of each ,month4 ,,the ,,oldest ,,established ,,and ,,the ,,recognised ,,representative ,,of ,,the ,,paper ,,trade ,,in ,,great ,,britain4 ,,special ,,reports ,,from ,,own ,,correspondents4 ,illustration3 ,,paper ,,makers' ,,circular1 ,rag ,merchants' ,gazette1 and ,price ,current4 ,,terms ,,for ,,subscription3-- ,united ,kingdom--,five ,shillings4 ,united ,states--,one dollar fifty cents4 ,british ,colonies--,six ,shillings4 ,post ,free ,france--,eight ,francs4 for ,germany--,six ,marks4 ,twelve ,months4 ,italy--,eight ,lires4 ,published in connection with this ,journal1 price #es41 ,paper ,makers' ,directory of all ,nations1 ,by ,s4 ,,chas4 ,,phillips4 ,,best ,,medium ,,for ,,advertisements4 ,offices3 #ai1 ,,cursitor ,,street1 ,,chancery ,,lane1 ,,london1 ,e4,c41 ,and #afj;a1 ,fleet ,street1 ,london1 ,e4,c4 ,,new ,,york3 #fj1 ,duane ,street4 ,,paris3 #ag1 ,rue de la ,banque4 ,,leipsic3 #c1 ,grimmaischer ,steinweg4 ,,amsterdam3 #fj1 ,rokin4 _/advertisement advertisement ,,established #ahdi4 ,j4 ,r4 ,,shorrock1 ,bolton ,road and ,lee ,foundries1 ,,darwen1 ,,lancashire1 ,,manufacturers ,,of ,,specialties ,,in ,,paper-,,makers' ,,machinery4 ,illustration ,,comprising3 ,,fourdrinier ,,paper ,,machines1 of the most modern construction1 of any specified width1 and having any required number of ,cylinders4 ,,single ,,cylinder1 ,,millboard ,,and ,,half-,,stuff ,,machines4 ,,revolving ,,and ,,flat ,,strainers 7including ,wrigley and ,robertson's ,patent74 ,,rag ,,and ,,rope ,,choppers of various sizes4 ,,spherical ,,or ,,cylindrical ,,revolving ,,boilers ,,and ,,vertical ,,boilers1 in ,wrought ,iron or ,steel4 ,,rag ,,engines ,,of ,,all ,,sizes1 with ,troughs cast in one piece1 or in segments4 ,,web ,,and ,,plate ,,glazing ,,calenders1 with ,rolls of ,chilled ,iron1 ,steel1 ,brass1 ,paper1 or ,cotton4 ,,ripping ,,and ,,winding ,,machines4 ,,reeling ,,machines 7including ,lowe's ,patent74 ,,improved ,,revolving ,,paper ,,cutters4 ,,square ,,and ,,circular ,,dusters4 ,,double ,,and ,,single ,,willows4 ,,hydraulic ,,presses1 ,,agitators1 ,,stuff ,,chests4 ,,mixing ,,pans ,,and ,,cisterns4 ,,double ,,and ,,single ,,acting ,,pumps of all sizes1 for ,water1 ,pulp1 or ,chemicals4 ,,brass ,,couch ,,and ,,press ,,rolls1 ,,and ,,brass ,,strainer ,,plates4 ,,steam ,,boilers1 ,,steam ,,engines4 ,,shafting1 ,,pulleys1 ,,pipes1 ,c4 ,,london ,,office3--#g1 ,,queen ,,victoria ,,street4 _/advertisement advertisement ,illustration ,,established #ahdi ,j ,r ,shorrock ,engineers1 ,bolton ,road ,lee ,foundries1 ,,darwen1 ,,lancashire ,london ,office #g ,queen ,victoria ,st4 ,e4 ,c4 ,illustration ,,makers ,,of ,,simple ,,and ,,compound ,,condensing ,,steam ,,engines ,,from #aj ,,to #ajjj ,h4,p4 ,,specialties ,,in ,,machinery ,,for ,,paper ,,making ,,paper ,,staining ,,calico ,,weaving1 ,,calico ,,printing ,,mill ,,gearing1 ,,pulleys ,,for ,,belt ,,or ,,ropes ,,up ,,to #cf ,,feet ,,dia4 ,,spur1 ,,bevel1 ,,mortice1 ,,helical ,,worm ,,wheels ,,in ,,iron1 ,,steel ,,or ,,phosphor ,,bronze ,,iron ,,castings ,,up ,,to #dj ,,tons ,,weight _/advertisement advertisement ,fcap4 #hvo1 cloth1 price #cs4 ,,the ,,practical ,,paper-,,maker4 ,,by ,,james ,,dunbar4 ,third ,edition4 ,,spons' ,,encyclop,,dia ,,of ,,raw ,,materials ,,and ,,manufactures4 ,parts ,,xv4 and ,,xvi4--,,fibrous ,,substances4 ,part ,,xxiv4--,,paper4 ,price #bs4 each ,part4 ,e4 ,f4 ,n4 ,,spon1 #abe1 ,strand1 ,london4 ,new ,york3 #ce1 ,murray ,street4 _/advertisement advertisement ,,pure ,,powdered #ih ,,caustic ,,soda4 ,,bleaching ,,powder ,,of ,,extra ,,strength4 ,,aluminate ,,of ,,soda1 ,substitute for ,alum3 a new ,specialty for ,paper ,makers4 ,,above ,,in ,,all ,,sizes ,,of ,,packages ,,to ,,suit ,,large ,,or ,,small ,,consumers4 ,correspondence invited4 ,special information given4 ,greenbank ,alkali ,works ,co41 ,,st4 ,,helens1 ,,lancashire4 ,,established #ahff4 _/advertisement advertisement ,,important ,,to ,,paper ,,makers4 #bith ,,year of ,,publication4 ,circulated throughout the ,civilized ,world4 ,the oldest established and recognised organ of the ,,stationery ,,and ,,paper ,,trades4 ,illustration3 ,,the ,,stationer1 ,,printer1 ,,and ,,fancy ,,trades' ,,register4 ,,to ,,advertisers4 information1 including ,scale of ,charges and ,quotations for ,advertisements1 will be forwarded on application to ,s4 ,,chas4 ,,phillips1 #afj;a1 ,,fleet ,,street1 ,,london1 ,e4,c4 ,,new ,,york3--#fj1 ,duane ,street4 ,,paris3--#bi1 ,rue ,des ,petites ,ecuries4 ,,leipsic3--#c1 ,grimmaischer ,steinweg4 ,,amsterdam3--#fj1 ,rokin4 ,,melbourne1 ,,sydney1 and ,,calcutta1 c4 ,quarter of a ,century of ,success4 ,best ,medium for ,paper ,makers' ,advertisements4 ,,published ,,on ,,the #fth ,,or #gth ,,of ,,each ,,month4 ,,terms ,,of ,,subscription3 ,home1 #fs4 #f;d4 ,indo-,colonial 7abroad generally71 #gs4 #f;d4 ,post-free4 _/advertisement advertisement ,crown #hvo1 cloth1 with ,illustrations1 ,price #es4 ,,workshop ,,receipts1 ,,for ,,the ,,use ,,of ,manufacturers1 ,mechanics1 ,scientific ,amateurs4 ,,by ,,ernest ,,spon4 ,,contents3 ,bookbinding -- ,bronzes -- ,candles -- ,cement -- ,cleaning -- ,concretes -- ,dyeing -- ,electro-,metallurgy -- ,enamels -- ,engraving -- ,etching -- ,firework ,making -- ,freezing -- ,fulminates -- ,furniture ,creams1 ,oils1 ,polishes1 ,lacquers1 and ,pastes -- ,gilding -- ,glass ,cutting -- ,glass ,making -- ,graining -- ,gums -- ,horn ,working -- ,india-rubber -- ,ink -- ,japans -- ,lacquers -- ,marble ,working -- ,matches -- ,mortars -- ,paper ,hanging -- ,painting in ,oils -- ,photography -- ,polishes -- ,pottery -- ,silvering -- ,soap-,solders -- ,taxidermy -- ,treating ,horn1 ,mother-o'-,pearl1 and like substances -- ,varnishes -- ,veneering -- ,whitewashing1 c41 c4 _/advertisement advertisement ,crown #hvo1 cloth1 #es4 ,,workshop ,,receipts 7,,second ,,series74 ,,by ,,robert ,,haldane4 ,devoted mainly to subjects connected with ,chemical ,manufactures4 ,an entirely ,new ,volume4 ,uniform in ,size1 ,style1 and ,type with the ,original #8,workshop ,receipts4' ,,contents4 ,acidimetry and ,alkalimetry -- ,albumen -- ,alcohol -- ,alkaloids -- ,baking ,powders -- ,bitters -- ,bleaching -- ,boiler ,incrustations -- ,cements and ,lutes -- ,cleansing -- ,confectionery -- ,copying -- ,disinfectants -- ,dyeing -- ,staining and ,colouring -- ,essences -- ,extracts -- ,fireproofing -- ,gelatine -- ,glue and ,size -- ,glycerine -- ,gut -- ,hydrogen ,peroxide -- ,inks -- ,iodine -- ,iodoform -- ,isinglass -- ,ivory ,substitutes -- ,leather -- ,luminous ,bodies -- ,magnesia -- ,matches -- ,paper -- ,parchment -- ,perchloric ,acid -- ,pigments -- ,paint and ,painting -- ,potassium ,oxalate -- ,preserving4 ,e4 ,f4 ,n4 ,,spon1 #abe1 ,strand1 ,london4 _/advertisement advertisement ,crown #hvo1 cloth1 #es4 ,,workshop ,,receipts 7,,third ,,series74 ,,by ,c4 ,g4 ,,warnford ,,lock1 ,f4,l4,s4 ,devoted mainly to ,electrical and ,metallurgical subjects4 ,,contents3 ,alloys -- ,aluminium -- ,antimony -- ,barium -- ,beryllium -- ,bismuth -- ,cadmium -- ,csium -- ,calcium -- ,cerrium -- ,chromium -- ,cobalt -- ,copper -- ,didymium -- ,electrics 7including alarms1 batteries1 bells1 carbons1 coils induction1 intensity1 and resistance1 dynamo-electric machines1 fire risks1 measuring1 microphones1 motors1 phonographs1 photophones1 storing1 telephones7 -- ,enamels and ,glazes -- ,erbium -- ,gallium -- ,glass -- ,gold -- ,indium -- ,iridium -- ,iron -- ,lacquers -- ,lanthanum -- ,lead -- ,lithium -- ,lubricants -- ,magnesium -- ,manganese -- ,mercury -- ,mica -- ,molybdenum -- ,nickel -- ,nisbium -- ,osmium -- ,palladium -- ,platinum -- ,potassium -- ,rhodium -- ,rubidium -- ,ruthenium -- ,silenium -- ,silver -- ,slag -- ,sodium -- ,strontium -- ,tantalum -- ,terbium -- ,thallium -- ,thorium -- ,tin -- ,titanium -- ,tungsten -- ,uranium -- ,vanadium -- ,yttrium -- ,zinc -- ,zirconium4 _/advertisement advertisement ,crown #hvo1 cloth1 #es4 ,,workshop ,,receipts 7,,fourth ,,series74 ,by ,c4 ,g4 ,,warnford ,,lock1 ,f4,l4,s4 ,devoted mainly to ,handicrafts and ,mechanical subjects4 #bej ,illustrations1 with complete ,index and a general ,index to the ,four ,series4 ,,contents3 ,waterproofing3 rubber goods1 cuprammonium processes1 miscellaneous preparations -- ,packing and ,storing articles of delicate odour or colour1 of a deliquescent character1 liable to ignition1 apt to suffer from insects or damp1 or easily broken -- ,embalming and ,preserving anatomical specimens -- ,leather ,polishes -- ,cooling ,air and ,water1 producing low temperatures1 making ice1 cooling syrups and solutions1 and separating salts from liquors by refrigeration -- ,pumps and ,syphons1 embracing every useful contrivance for raising and supplying water on a moderate scale1 and moving corrosive1 tenacious1 and other liquids -- ,desiccating3 air- and water-ovens1 and other appliances for drying natural and artificial products -- ,distilling3 water1 tinctures1 extracts1 pharmaceutical preparations1 essences1 perfumes1 and alcoholic liquids -- ,emulsifying as required by pharmacists and photographers -- ,evaporating3 saline and other solutions1 and liquids demanding special precautions -- ,filtering3 water1 and solutions of various kinds -- ,percolating and ,macerating -- ,electrotyping -- ,stereotyping by both plaster and paper processes -- ,bookbinding in all its details -- ,straw ,plaiting and the fabrication of baskets1 matting1 etc4 -- ,musical ,instruments3 the preservation1 tuning1 and repair of pianos1 harmoniums1 musical boxes1 etc4 -- ,clock and ,watch ,mending3 adapted for intelligent amateurs -- ,photography3 recent development in rapid processes1 handy apparatus numerous recipes for sensitizing and developing solutions1 and applications to modern illustrative purposes4 ,e4 ,f4 ,n4 ,,spon1 #abe1 ,strand1 ,london4 _/advertisement advertisement ,,spons' ,,encyclop,,dia ,,of ,,the ,,industrial ,,arts1 ,,manufactures1 ,,commercial ,,products4 ,,edited ,,by ,c4 ,g4 ,,warnford ,,lock1 ,f4,l4,s41 c41 c4 ,in ,super-royal #hvo1 containing #bajj pp41 and ,illustrated by nearly #aejj ,engravings4 ,can be had in the following bindings3-- s4 d4 ,in #b vols41 cloth #c #aj #j ,in #e divisions1 cloth #c #aa #f ,in #b vols41 half-morocco1 top edge gilt1 bound in a superior manner #d #aj #j ,in #cc monthly parts1 at #bs4 each4 ,any ,part can be had separate1 price #bs41 postage #b;d4 ,,complete ,,list ,,of ,,all ,,the ,,subjects4 ,acids1 ,parts #a1 #b1 #c ,alcohol1 #c1 #d ,alkalies1 #d1 #e ,alloys1 #e1 #f ,arsenic1 #f ,asphalte1 #f ,aerated ,waters1 #f ,beer and ,wine1 #f1 #g ,beverages1 #g1 #h ,bleaching ,powder1 #h ,bleaching1 #h1 #i ,borax1 #i ,brushes1 #i ,buttons1 #i ,camphor1 #i1 #aj ,candles1 #aj ,carbon1 #aj ,celluloid1 #aj ,clays1 #aj ,carbolic ,acid1 #aa ,coal-tar ,products1 #aa ,cocoa1 #aa ,coffee1 #aa1 #ab ,cork1 #ab ,cotton ,manufactures1 #ab1 #ac ,drugs1 #ac ,dyeing and ,calico ,printing1 #ac1 #ad ,dyestuffs1 #ad ,electro-,metallurgy1 #ad ,explosives1 #ad1 #ae ,feathers1 #ae ,fibrous ,substances1 #ae1 #af ,floor-cloth1 #af ,food ,preservation1 #af ,fruit1 #af1 #ag ,fur1 #ag ,gas1 ,coal1 #ag ,gems1 #ag ,glass1 #ag ,graphite1 #ah ,hair ,manufactures1 #ah ,hats1 #ah ,ice1 ,artificial1 #ah ,indiarubber ,manufactures1 #ah1 #ai ,ink1 #ai ,jute ,manufactures1 #ai ,knitted ,fabrics 7,hosiery71 #ai ,lace1 #ai ,leather1 #ai1 #bj ,linen ,manufactures1 #bj ,manures1 #bj ,matches1 #bj1 #ba ,mordants1 #ba ,narcotics1 #ba1 #bb ,oils ,fatty ,substances1 #bb1 #bc1 #bd ,paper1 #bd ,paraffin1 #bd ,pearl and ,coral1 #bd ,perfumes1 #bd ,photography1 #bd1 #be ,pigments and ,paint1 #be ,pottery1 #be1 #bf ,printing and ,engraving1 #bf ,resinous and ,gummy ,substances1 #bf1 #bg ,rope1 #bg ,salt1 #bg1 #bh ,silk1 #bh ,skins1 #bh ,soap1 ,railway ,grease1 and ,glycerine1 #bh1 #bi ,spices1 #bi ,starch1 #bi ,sugar1 #bi1 #cj1 #ca ,tannin1 #ca1 #cb ,tea1 #cb ,timber1 #cb ,varnish1 #cb ,wool and ,woollen ,manufactures1 #cb1 #cc ,e4 ,f4 ,n4 ,,spon1 #abe1 ,strand1 ,london4 _/advertisement ,,transcriber',s ,,note3 ,original spelling and grammar have been generally retained1 with some exceptions noted below4 ,original printed page numbers are shown like this3 #eb4 ,original small caps are now uppercase4 ,italics look like this4 ,footnotes have been relabeled #a-ah1 and moved from within paragraphs to nearby locations between paragraphs4 ,the transcriber produced the cover image and hereby assigns it to the public domain4 ,original page images are available from archive4org--search for 8gri#ccabejjgihaifh04 ,subscripts are indicated with underscore followed by curly brackets1 e4g4 8,h#b,o04 ,some missing full stops have been inserted4 ,many ditto marks have been eliminated1 replaced by repeated text4 ,enlarged curly brackets 80 employed to combine information in two or more lines or columns have been eliminated1 by restructuring text if necessary4 ,one such instance is the table on page #ci4 ,the table on page #dd and some other large tables were moved from their original locations inside a paragraph of text to nearby locations between paragraphs4 ,the page #dd table was also divided into two parts1 after column six4 ,illustrations have also been moved from within paragraphs of text to nearby locations between paragraphs4 ,page #ab4 8tranformation0 to 8transformation04 8,c#ab;,h#bj,o#aa0 to 8,c#ab;,h#bb,o#aa04 ,page #adn4 ,the note had no anchor2 a new one has been inserted after 8in sealed glass04 ,page #ag4 8chemisty0 to 8chemistry04 ,page #fe4 8revolution0 to 8resolution04 ,page #acf4 8being therefore equivalent to one mgrm0 is retained1 but presumably should be read 8being therefore equivalent to ten mgrm04 ,page #aifn4 ,the note had no anchor in the text4 ,a new one has been inserted after 8papers published by the ,institute for #ahhe401 as a plausible guess4 ,page #aig4 8following seven groups0 to 8following eight groups04 ,page #bbj4 8the following way0 to 8the following may04 ,page #bde4 ,a section of advertisements begins here4 ,this section in the original printed book depended heavily upon the advantages of typography1 graphics1 and page-breaks4 ,in this simple text edition1 the codes advertisement and _/advertisement have been inserted fore and aft1 for each ad4