STITTJTE OF CHEMISTRY 
 
 OF 
 
 GREAT BRITAIN AND IRELAND. 
 
 FOUNDED, 1877. 
 INCORPORATED BY ROYAL CHARTER, 1885. 
 
 LECiURES 
 
 ON 
 
 CELLULOSE 
 
 By 
 C. F. CROSS 
 
 (Fellow of the Institute], 
 
 3O, BLOOMSBURY SQUARE, LONDON, W.C, 
 1912. 
 
A gric . - Foresti} 7 
 
THE 
 
 INSTITUTE OF CHEMISTRY 
 
 OF 
 
 GREAT BRITAIN AND IRELAND. 
 
 FOUNDED, 1877. 
 INCORPORATED BY ROYAL CHARTER, 1885. 
 
 LECTURES 
 
 ON 
 
 CELLULOSE 
 
 By 
 C. F. CROSS 
 
 (Fellow of the Institute). 
 
 30, BLOOMSBURY SQUARE, LONDON, W.C. 
 
 1912. 
 
-. \ 
 
 
 The Lectures were delivered before the Institute of 
 Chemistry, at University College, London, on 
 January 26th (Sir Wm. Ramsay, KC.B., 
 presiding), and February 2jrd, 1912 (Professor 
 J. Norman Collie presiding). 
 
 Mam Library 
 
CONTENTS. 
 
 Lecture I. 
 
 SYLLABUS. Cellulose in relation to Science and Industry, more 
 particularly in relation to specialisation, and the career of chemist. 
 
 The three dimensions of specialisation. 
 
 Cellulose and Derivatives : prototypes of Colloids. 
 
 Colloids. Preponderating importance of Colloids. Investigations of 
 Colloids, and Colloidal State, hitherto mainly " two dimensional." 
 
 Suggestions of systematic extensions by way of Cellulose and Deri- 
 vatives. 
 
 The "Normal Cellulose" and normal processes of preparation; 
 significance in science and industry. 
 
 "Systematic Chemistry of Cellulose" on half-sheet of notepaper. 
 Specialist literature of Cellulose, of library dimensions. Meaning of 
 this relation. 
 
 Ligno-Celluloses ; constitution. Methods of resolution. Wood 
 Celluloses. By-products, and utilisation, illustrative of Chemist's Balance 
 Sheet of Industrial processes. 
 
 Special study of Chlorination process as a quantitative method. 
 Problem of adaptation to industrial requirements as a typical investigation. 
 
 Diagrams. 
 
 Statistics of Cellulose Products and Derivatives. 
 Comparative Statistics of Chemical Manufactures. 
 Jute Lignocellulose Schematic Formula. 
 Wood-pulping Processes. 
 
 Lecture II. 
 
 SYLLABUS. Some types of Carbohydrate Colloids as an evolutionary 
 series : 
 
 Starch. "Feculose" and the true Starch Colloid. Permanent aqueous 
 solutions : Applications. 
 
 Hemi-Celluloses from Seed-endosperms. Tragasol : Industrial Appli- 
 cations. Cutiloid, a new colloid : Applications in paper and leather 
 industries. 
 
 Cellulose Hydrates. Hydration by chemical reaction ; by mechanical 
 treatment. Papermaking beating process, in relation to properties of 
 paper. Some margins of industrial value. Dyeing processes in relation 
 to Chemical-colloidal constitution. Cellulose Hydrates as basis of artificial 
 structural forms. 
 
 Form and Dimensions. Practical histology in Chemical Investigations. 
 
 Physical investigations of Colloidal State by way of Starch-Cellulose 
 series. 
 
 Cellulose and Industrial Supply. Wood Cellulose and Forestry. 
 Further utilisation of World's Wastes : examples of wastes on colossal 
 scale. 
 
 List of Exhibits. 
 
 A2 
 
The Paper on which the Text is printed has been selected 
 as conforming with the following specification : 
 
 Substantially " rag " (cotton and flax) cellulose free from 
 esparto, lignocellulose, and mineral loading. 
 
Lecture I. 
 
 In accepting the invitation of the Institute to take a part 
 in the scheme of lectures under which it seeks to extend its 
 constructive work outside and beyond the more fundamental 
 academic influences, I take it that I am expected to address 
 myself chiefly to the younger members, and to give them some 
 of the results, so far as they can be so communicated, of thirty 
 years' experience as a specialist : a record which may be pre- 
 sumed to furnish points of determination, guidance and 
 warning to a younger generation. I am able to presume upon 
 a very general interest in the subject of " Cellulose " arising 
 out of the unique position of the substance itself in the world 
 of things. 
 
 As a chemical individual, however, it has only a very 
 sectional corner in the fabric of the science ; and specialists' 
 investigations of cellulose cannot claim to have contributed 
 matter of any importance to systematic science. Consequently, 
 we may be even thought to be hypercritical if we point out 
 that the sectional treatment of " Cellulose " in the standard 
 text-books is always inadequate and largely inaccurate. As 
 regards the past and the ever-elusive present, we may admit 
 that " it really doesn't matter" that our text-books attach little 
 importance to the subject ; but as a subject with a future 
 it claims critical attention. 
 
 And here we may note a very common presumption which 
 is on the way to crystallise to a prejudice, namely, that 
 cellulose is merely an eccentric form of dextrose or carbo- 
 hydrate matter, and connotes a constitutional problem, 
 ultimately to be elucidated in terms of current systematic 
 chemistry ; presenting, therefore, no problems of prospective 
 
scientific importance, though a useful hunting ground for 
 adventurous specialists of an " industrial " turn of mind. 
 
 Admitting the humour of this criticism, and further 
 recognising that a sense of humour is a necessary part of the 
 equipment of a chemist about to adventure on the high seas of 
 professional life and trouble, we have nevertheless to propound 
 a more serious view of our subject-matter. It would be out 
 of place to argue the following propositions : we present them 
 for the thoughtful consideration of younger students. 
 
 Cellulose is organised matter: "organic" matter in special- 
 ised mass forms. As an effect or product of life and in turn 
 the arena of vital processes, we may affirm that no two portions 
 of cellulose are identical ; neither is the chemist's cellulose 
 identical with the biologist's cellulose. The former connotes 
 a series of degradation products of the Iatter 3 and we have no 
 means of re-ascending the scale. 
 
 The total synthesis of carbon-compounds is sometimes 
 confused with quantitative knowledge of the forms of matter 
 so manipulated. This leads to superstition. The synthesis 
 of " organic " compounds is supposed to suggest a potential 
 synthesis of organised matter by laboratory process. As a 
 matter of fact and clear-thinking, this is a subjective creation, 
 a poetic fancy, as little grounded as was the dogmatic asser- 
 tion of the older chemists that " organic " compounds were 
 exclusively producible by vital force. 
 
 In correcting this misconception, and setting free an 
 immense territory for thought and investigation, latter-day 
 chemists are inclined to extend the negation into a dogmatic 
 elimination of the conception of life as a physical or super- 
 physical agency. "/7s aiment par instinct de faire de la 
 nature morte"* In other words it is, or has been, fashionable 
 
 * Etude Critique du Mate'rialisme et du Spiritualisme par la physique 
 experimentale." RAOUL PICTET. (Geneva, 1897.) 
 
in " science " to regard life as a property of ultimate matter, 
 organic form as the analogue of crystallisation, and vital 
 effects as a side issue of chemical philosophy. 
 
 It is necessary to make passing mention of questions which 
 must arise in the serious study of the problems of the border- 
 land between chemistry and biology, and to enjoin on the 
 young student the duty of serious and clear thinking in this 
 region. 
 
 If we now turn from " science," i.e., systematic science, to 
 human industry, cellulose emerges from its sectional corner 
 to a position of predominating importance. A few statistical 
 figures will indicate this predominance (p. 30). 
 
 Our cotton manufactures are estimated at the annual gross 
 figure of ^125,000,000 at factory cost; hemp, linen and jute 
 goods, products to be ranked as essentially cellulose, at 
 ^"20,000,000 ; of this bast-fibre section, jute manufactures 
 may be estimated in terms of imports of the raw fibre at, say, 
 ^"8,000,000 ; in the same group are ropes and twines at 
 ^"4,000,000. Paper and boards are next in order at ^"14,000,000. 
 These, it must be remembered, are primary products they 
 are the basis of further manufactures, of which we may 
 mention, for instance, lace and hosiery, books and news- 
 papers, etc. 
 
 These more obvious industrial applications of cellulose 
 products by no means exhaust the field. 
 
 " Straw " hats which are made from cereal straws, white 
 woods (" chip ") and miscellaneous vegetable products, etc., 
 represent an industry approaching /"i, 000,000 per annum. 
 
 The wood and timber trades have to be taken into reckon- 
 ing and some guide to their industrial importance is obtained 
 from the statistics of imports of the raw materials; the 
 gross figure of ^25,000,000, suggesting a very much larger 
 value for their final manufactured forms. 
 
 From these modes of manufacture of vegetable raw 
 
8 
 
 materials, in which their structural and essential chemical 
 characteristics are maintained, and leaving altogether out of 
 account the part played by cellulose as a fundamental con- 
 stituent of all agricultural and gardening produce, we pass to 
 the group of cellulose derivatives. 
 
 As certainly derived in the main from cellulose by processes 
 of regulated destruction, in effect of constructive destruction, 
 we must mention coal, of which our own production reaches 
 the colossal total of 250,000,000 tons per annum, in value, say, 
 ;" 1 50,000,000. 
 
 From such figures and their indirect consequences, upon 
 which we need not dilate, it seems an anti-climax to pass to 
 the nitro-celluloses, which, on the other hand, are direct 
 derivatives. But if coal dominates the productive and con- 
 structive life of an industrial community, its powers of offence 
 and defence under modern conditions of life are in an 
 important sense dependent upon nitro-cellulose powders. 
 Without assigning a money value to the industry in explosives, 
 they have an importance sui generis and self-evident. 
 
 The nitro-celluloses are the essential component of 
 celluloid and xylonite, and in the form of films are 
 indispensable to photography in all departments ; these 
 applications of cellulose represent not merely large industrial 
 values, but contributions of useful and aesthetic effects, not to 
 be comprehended in trade returns. 
 
 It is quite unnecessary to labour this theme to impress its 
 consequences upon this audience. Summing up our sketch, 
 it is clear that qud productive industries, cellulose occupies 
 a first position and has only one rival in respect of magnitude, 
 which is iron (and steel), with the engineering industries 
 connoted by those comprehensive terms, the gross figures of 
 our production in this sphere approaching ^"400,000,000. 
 
 Even the fermentation industries, at a gross figure of, say, 
 
9 
 
 ^70,000,000, w i tn their monstrous load of Excise contributions, 
 fall into quite a secondary category of importance. 
 
 Incidentally we may remark that the industries of most 
 direct interest to us as chemists, viz., the manufactures of 
 "heavy chemicals," chemical raw materials, and the highly 
 specialised products of organic synthesis, including dye-stuffs, 
 are of altogether subordinate moment, if not insignificant. 
 Remarkable as is this disproportion, it appears to escape 
 attention in many of the public discussions of the relative 
 progress of chemical industry in England and Germany. 
 (See Diagram, p. 30.) Without touching controversial side 
 issues, we have to complete this aspect of our subject by 
 grouping cellulose in the broadest scheme of classification 
 of industries. Cellulose is a colloidal substance and the 
 prototype of the colloids. In the industrial and widest sense 
 the colloids are useful for their structural qualities, and on 
 this view we group together industries of apparently widely 
 divergent characters : India rubber oils, paints and varnishes 
 glass, pottery and bricks, mortars and cements gelatin, 
 casein and starch silk, wool,, and leather. 
 
 Addressing an audience trained in method, both of mind 
 and practice, it would be gratuitous to justify this classifi- 
 cation or to follow up in detail the consequences of the 
 organic relations of these heterogeneous spheres of human 
 activity. To an untrained mind the connection between a 
 sheet of glass and a sheet of paper may not be obvious. But 
 a slight transformation of the paper substance without loss of 
 weight makes it into a transparent homogeneous coherent 
 sheet, indistinguishable from the vitreous colloid. 
 
 Resuming the thread of our exposition, if cellulose is 
 industrially predominant, a fortiori the predominance of the 
 industries in colloids is overwhelming. In this order of idea 
 and on this perspective we re-discover the world of nature in 
 our own artificial system. 
 
10 
 
 As chemists we are aware that the beginnings of our 
 science were those of a study of Natural History. We have 
 only to turn for recreative study of this theme to the 
 philosophical works of Robert Boyle, representing the thought 
 of the seventeenth century, or to a work such as " Elemens 
 d'Histoire Naturelle et de Chimie" of de Fourcroy, represent- 
 ing the physical conceptions of the eighteenth century, to 
 appreciate the extraordinary divergence of thought and 
 investigation of the nineteenth century. Our pioneers have 
 spent that century in the monastic seclusion of the cloisters 
 with magnificent result be it confessed and it is now the 
 calling of the chemist to apply the grammars and dictionaries 
 elaborated during this necessary period of self-contained 
 activity to a new reading of the natural order. 
 
 Evidence that such a movement is in active progress is 
 the recognition of the problem of the "Colloidal State" of 
 matter as an abstract subject of investigation, that is, as a 
 problem of pure science and apart from any question of 
 industrial result. This generalised view of the colloidal 
 state as a permanent characteristic of particular forms of 
 matter, and a potential form of an indefinitely wide range of 
 chemical individuals, is well set forth in Wo. Ostwald's 
 " Grundriss der Kolloidchemie." 
 
 A curious feature of this leading text-book of the subject 
 is that " Cellulose " is not even mentioned, and " Zellstoff" 
 once only ! 
 
 This observation has led us to remark, in our synopsis, that 
 modern or later specialisation in colloidal phenomena has 
 been mainly characterised by superficial range of treatment ; 
 whereas it is in the direction of the third dimension for 
 investigation to move with the greatest promise of progress. 
 Our opinion is that cellulose and cellulose derivations supply 
 an ideal region for the profound and exhaustive application of 
 physical methods directed to the elucidation of the colloidal 
 
11 
 
 state. The fundamental constants are for this, as for any- 
 other state of matter: volumes and solution volumes and 
 changes of specific volume with temperature, viscosity (of 
 solutions), elasticity and mechanical properties (of solids), and 
 in the next order the relations of these substances to the 
 various forms or phases of energy, more particularly to heat r 
 but also to electricity and light. 
 
 Now we have also to remember that cellulose is the 
 extreme term of the series of so-called carbohydrates, and 
 that this series, cellulose, hemi-cellulose, starch, dextrine, 
 maltose and dextrose, presents a mass of organic relationships 
 which must have their physical correlatives. 
 
 We have to remember, too, that the chemist does not 
 lightly rush in to the region of physical measurements. The 
 paradox of the physical laboratory is that the one thing to be 
 positive about is the error of observation, and that the quanti- 
 fication of error is often by far the most exacting, and perhaps 
 interesting, part of an investigation. This quite certainly will 
 be the case in investigating the cellulose, hemi-cellulose, starch 
 series, and may have proved a deterrent to many, other- 
 wise attracted to an obviously fruitful field of work. This 
 discipline of the physicist would have a parallel to the chemist 
 in the rare cases when he has to take a major interest, not in 
 the chemical individuals, which are his familiar friends, but in 
 their incidental impurities a case which arises in investigations 
 of the mechanism of reactions and in determinations of atomic 
 weight. This raises a point in relation to the colloidal 
 state which in process of time may also become a subject of 
 direct investigation. All organic colloids of natural origin 
 present an incidental " impurity " of inorganic matter. Only 
 in certain cases are these investigated or specifically estimated, 
 and chiefly as constituents of agricultural produce. They 
 represent, on the debtor side of the account, exhaustion of the 
 soil ; and they indicate on the creditor or positive side special 
 
12 
 
 functions of undoubted moment in the vital processes. It is 
 quite certain that the progress of knowledge of colloids, or 
 rather of the colloidal state, will impose upon us a re-investi- 
 gation of the inorganic or " ash " constituents of plant colloids, 
 and the co-ordination of a vast amount of material faithfully 
 recorded that is, " faithfully " in the fuller sense of faith in a 
 scientific meaning and value remaining for future workers to 
 confer upon them. 
 
 As a general criticism, therefore, the subject of colloidal 
 matter is presented to the student rather as the play of 
 " Hamlet " with the part of the prince left out. 
 
 I take it, it is not the function of a lecturer to argue, and I 
 must be allowed to commend the above statement as a subject 
 for an examination essay or a students' debate. 
 
 We have now to turn our attention to the central subject 
 of our exposition : cellulose as a chemical individual, that is, 
 in relation to systematic chemistry ; and as a necessary preface 
 to the question of a " Normal Cellulose." 
 
 The necessity of a definition will be at once evident from 
 the fact that our chemical filter papers are usually supposed to 
 represent a normal cellulose, and are, in fact, frequently taken 
 as a starting point of scientific investigation of cellulose : 
 whereas a very slight knowledge of the technology of paper- 
 making would suggest, a priori^ the improbability of any of its 
 products reaching this standard ; and a chemical examination 
 would soon dispose of any such claim. 
 
 To make this clear we must presume a basis of exact 
 knowledge, and we set out the fundamental chemistry of 
 cellulose in the shortest possible compass. Actually, the 
 typical cellulose is the cotton fibre purified by special pro- 
 cesses, to which it is assumed to offer complete resistance, 
 whereas the heterogeneous complex of " non-cellulose " con- 
 stituents of the natural fibre are removed under treatment as 
 soluble derivatives. 
 
13 
 
 Thus isolated and purified, it may be shortly described as 
 follows : 
 
 Cellulose = n. (C 6 H 10 O 6 ) or n. C 6 H 7 O 2 .(OH) 8 
 a saturated compound of unascertained molecular dimensions ; 
 insoluble in all neutral solvents ; resists action of halogens, of 
 alkaline solutions and oxidants within certain limits ; hydrated 
 and dissolved by zinc chloride (5O/ solution AqJ and 
 cuprammonium solutions (15% NH 3 , 3% CuO) ; hydrated 
 with structural changes (mercerisation) by solutions of alkaline 
 hydrates (15% NaOH). Synthetic reactions, mainly those of 
 its alcoholic OH groups : 
 
 (a) With monobasic acids (or anhydrides) giving 
 Nitrates : retaining fibrous structure : limit of esteri- 
 
 fication s.ONO 2 . 
 Acetates : acetylation usually attended by solution : 
 
 normal limit 3.0 Ac : further acetylation of hydro- 
 
 lysed derivatives. 
 Benzoates : monobenzoate fibrous : dibenzoate (limit) 
 
 amorphous. 
 Formates : esters higher than monoformate of 
 
 doubtful relationship to original. See Chem. Soc. /., 
 
 99, 1,450 (1911), Cross and Bevan. 
 
 (b) With CS 2 (and NaOH) giving cellulose xanthogenic 
 
 acid CSg^ aHl9 9 : alkali salts water-soluble. 
 
 Reactions of decomposition: 
 
 (c) With sulphuric acid giving disulphuric esters, but 
 
 with attack and disintegration of aggregate, the 
 hydrolysis proceeding to extreme limit of resolu- 
 tion to dextrose. 
 
 (d) With aqueous acids and oxidants a complex series of 
 
 products known as hydrocelluloses, oxycelluloses, 
 differing only fractionally in elementary composi- 
 tion from n.C 6 H 10 O 6 . 
 
u 
 
 In characterising a " normal cellulose," it will perhaps be 
 evident that we have to erect our standard from the inside. 
 It is the paradox of organic chemistry proper the 
 chemistry of organised matter that it is a chemistry of which 
 the fundamental relationships are unascertained. Investiga- 
 tion in this region may be compared to living without clocks 
 -or time standards, which means that to know where you are 
 in space or time at any stage of investigation you require to 
 take bearings ; and, moreover, as the sun and fixed stars are in 
 this region invisible, you are limited to observations of the 
 moon ! This analogy is not chosen at random ; it represents 
 this fact : while our major appeal is still to the balance, we 
 cannot pass from particular relative weights to the 
 generalised or transcendental relationships of molecular units. 
 We have no fixed point outside the system under observa- 
 tion. Thus, in a series of celluloses, or rather specimens of 
 a particular cellulose, we observe a varying degree of resist- 
 ance to a certain treatment measured, say, by loss of weight. 
 Thus aqueous sodium hydrate at 15 per cent, strength 
 produces the very characteristic change known as mercerisa- 
 tion. We submit to this treatment specimens all of bleached 
 cotton cellulose, and all ranking with papermakers as a 
 normal product : at the extreme limit in the one direction is 
 a specimen giving up 20 per cent, of its weight to the 
 mercerising alkali ; at the other end a specimen containing 
 -2 per cent, of alkali-soluble cellulose. This gradation, quite 
 unmarked by external characteristics, already suggests a cotton 
 ^cellulose entirely resistant, qud loss of weight, to the alkali. 
 An industrial product fulfilling this requirement is a calico- 
 printer's cotton cloth, prepared by the process of "madder 
 bleaching" ; of this we submit a specimen which we have tested. 
 But this test does not rank with the calico-printer. He 
 requires certain associated properties in his bleached product, 
 and is satisfied if these are fulfilled ; they are : 
 
15 
 
 (a) Maximum tensile strength, i.e., full maintenance of the 
 structural properties of the fibre ; (6) maximum of non- 
 reactivity as a chemical individual. 
 
 The meaning of the " madder bleach " is that the fabric will 
 not take up alizarin from the dye-bath of this colouring 
 matter ; the chemical equivalent term is non-reactive. Designs 
 are printed in thickened mordants upon the cellulose fabric, 
 and suitably " fixed." In the dyeing treatment of the whole 
 fabric, the printed portions take up their complement of dye- 
 stuff with calculated modification of shade or hue ; the unprinted 
 portion is required to resist, so that when washed up and cleaned 
 from mechanically-adhering colouring matter, it shows the 
 contrast of the pure white ground. A little reflection will 
 show that, whatever view may be taken of the course of 
 dyeing phenomena, we are dealing here with the negative 
 property of non-reactivity or chemical inertness. We may, 
 therefore, add a dyeing test, as a qualitative measure of a 
 normal cellulose. It will be also evident that when cellulose 
 under attack begins to undergo chemical, i.e., constitutional, 
 modification, the first evidence of reactivity is the setting free 
 of CO-groups, of which the familiar Fehling's solution is the 
 simplest test and measure. 
 
 Incidentally we have mentioned the fundamental charac- 
 teristics of cellulose as a structural colloid. These are 
 measured in terms of resistance to rupture, with the 
 associated quality of elongation under strain. 
 
 We have now defined three fundamental constants in 
 terms of a " normal cellulose." 
 
 (1) Quantitative resistance to mercerisation ; 
 
 (2) Non-reactivity in terms of " Fehling " and dyeing 
 
 tests ; 
 
 (3) Structural integrity measured in terms of resistance 
 
 to rupture, and of elongation under strain (elasticity). 
 
16 
 
 This is a very firm tripod for the support of a standard of 
 cellulose quality. But as a standard of science we have to 
 remember the limitations of a self-contained standard. In 
 the field of analogy we might consider the case of water and 
 its fundamental properties. What do they know of water 
 who only water know ? They may marvel at its aqueosity, 
 but should they find themselves, e.g., disappointed with the 
 Atlantic or Niagara, where is their reserve of emotional 
 suggestion? In the co-ordinate region of science, where 
 would the physicist be in the knowledge of water if he 
 had no critical standpoints external to water, or if 
 temperature were the only measure of heat ? 
 
 Now the cellulose standard must be established from the 
 standpoint of its limitations and when this is recognised, we 
 think our schools of technology will find a very useful work to 
 do, to measure in terms, as given, the degree of resistance of 
 cellulose to 
 
 Hydrolysis j Acid 
 
 and I and 
 
 Oxidation Alkaline. f 
 
 To our present audience there is no need to argue the 
 matter. Some will see it presently, that is at once, in the 
 language of Shakespeare, or at some future date in the latter- 
 day acceptation of the term; but, in either case, none the 
 better or more clearly for our much speaking. 
 
 But the industrial value of a standard of cellulose may 
 not be so obvious. And here we are really able to touch only 
 the fringe of a large subject. The particular chemical industry 
 which requires for its raw material a cellulose of nearest 
 approach to the normal, is the manufacture of nitro-cellulose 
 explosives. This, for the reason that stability of the nitric 
 esters is essentially conditioned by inertness of the cellulose, 
 
 t See The Chemical World I., p. 84, 1912. 
 
17 
 
 and undermined by modification in the direction of setting 
 free oxidisable groups. The tests usually adopted are 
 of the same character as those we have sketched, though 
 differing in detail. 
 
 But this and others of what we may consider our special 
 or specialised applications of cellulose are of minor importance 
 in regard to industrial value. The industries of more general 
 interest are those of textiles and paper. We have already 
 alluded to the calico-printer's requirements of a specially pure 
 cellulose. We may remark that the exigency and its fulfil- 
 ment are largely matters of empiricism. We may also remark 
 that the papermaker treats the chemistry of his raw material 
 as a matter of insignificant moment. It is a resistant sub- 
 stance chemically and mechanically, and so long as his 
 bleaching or purifying treatments give the result of sufficiency 
 and efficiency, as judged by external criteria, and the mechani- 
 cal treatments, the practical and commercial result, he does 
 not invoke the aid of the chemist to teach him his business. 
 
 In this neglect we can assure our audience there are elements 
 of tragedy, pathos, and comedy which the student may survey, 
 and in which he may take interest according to his temperament. 
 The tragedy of industrial wealth destroyed and lost, the pathos 
 of so much avoidable loss, and the comedy of the really dull 
 person of the play being quite unaware of the possibility of the 
 wrong man being whipped, or why he should laugh under the 
 lash. But we must warn the young student not to take 
 such revelations too seriously. Our humorists have unwittingly 
 spoiled a good deal of fun; and in these days of "many 
 masters " it is better not to attempt a setting in order on the 
 large scale. It is sufficient if we, as chemists, can see and 
 formulate an ideal, and apply it " at home." 
 
 Thus the "normal cellulose" is an ideal product and a 
 scientific conception, still perhaps requiring definition by 
 results of investigations, which investigations may well be 
 
 B 
 
18 
 
 undertaken by our schools of technology. It is of practical 
 moment in the cellulose industry, just as a gold standard is 
 essential for regulation of coinage. It is also important as a 
 criterion of processes of isolating or purifying celluloses. 
 
 These processes we have to examine in illustration of first 
 principles. 
 
 We are limiting ourselves at present to cotton, and the 
 purification or bleaching of cotton is a relatively simple 
 matter. The impurities to be removed are exceptionally low 
 in weight proportion, and readily yield to alkaline saponification, 
 and the residues to oxidation. In industrial work, this means 
 a boiling treatment under pressure with caustic alkali, and 
 oxidation of the coloured residues by weak solution of 
 hypochlorites. 
 
 In a " madder bleach," the alkaline treatment is divided 
 into two : a lime boil, followed (after " souring " to clear from 
 residues of basic lime) by pressure-boiling with soda and with 
 addition of rosin. 
 
 These alkaline treatments, as we shall subsequently and 
 more particularly show, are unsatisfactory to the technologist 
 as they are extremely complex processes and very imperfectly 
 elucidated. In the 'case of cotton, the non-cellulose to be 
 attacked and removed is a heterogeneous complex of proteid 
 residues, carbohydrates of the pectic group, and a "wax- 
 resin " mixture, the latter associated with the cuticle of the 
 fibre. It is the latter which is relatively resistant to alkaline 
 hydrolysis, and the action of the alkali is impeded by the 
 gelatinisation of " pectic " bodies in the initial stage of the 
 attack. It is also necessary to consider the special physical 
 and mechanical conditions of a mass of cloth in contact with a 
 mass of alkaline liquid from five to seven times its weight 
 only ; and, further, the mass of cotton having the structural 
 complications not only of the ultimate fibre, but of the spinners 
 twist and the interlocking contacts of the woven fabric. On 
 
19 
 
 this expose it is not difficult to appreciate the specific advan- 
 tages of the preliminary lime boil, and the indications of 
 an important general principle of chemical economy, that of 
 division of effect, fairly comparable with division of labour in 
 manual operations. 
 
 This leads us to the consideration of a group of processes 
 similarly directed to the isolation of a pure cellulose, but of 
 more distinctive character. These are the industrial treat- 
 ments of the woods for the preparation of papermaking cellu- 
 loses or pulp. We can only sketch these very briefly, and as 
 illustrating first principles. 
 
 The wood substance is a lignocellulose a colloidal com- 
 plex of cellulose and non-cellulose, or lignone, the latter a 
 highly varied though homogeneous complex of groups. This 
 is not an occasion for arguing the controversial theme of the 
 constitution of this lignone complex and its relation to the 
 cellulose. In a work now in the press (" Researches on Cellu- 
 lose," iii. Cross and Bevan) we give reasons for adopting the 
 following views for the lignone. 
 
 (i) A constitutional schematic formula, that is of general 
 or typical significance as under : 
 
 H- [CH 2 .co] a H 
 
 HgO.Hl^ y AJ ..v^<^.i..i 8 Cellu- 
 
 CO 
 
 Cellu- 
 lose a. 
 
 lose 
 
 (See Diagram, p. 31.) 
 
 (2) The combination of lignone and cellulose is not of the 
 familiar type of a union of " residues," but an interpenetration 
 of two colloidal systems of such order, and so affecting the 
 ultimate component groups, so that their reactivities are 
 modified similarly to those of groups united by definite 
 chemical bonds. 
 
 B 2 
 
20 
 
 The lignone complex is reactive in various directions. 
 We demonstrate those which are more obviously character- 
 istic : various colour reactions with aromatic bases and 
 phenols, reactions with the halogens and oxidants demon- 
 strating the unsaturated constitution of its typical groups ; 
 and a special reaction with ferric ferricyanide in which, with 
 the unsaturated characteristics of the complex, . it shows an 
 exceptional reactivity as a homogeneous colloidal system (see 
 J. Soc. Chem. Ind., 12, 104, 1893). 
 
 The isolation of cellulose from the lignocellulose complex 
 is a problem of chemical industry or manufacture. 
 
 Industrially, the simplest process is that of boiling or 
 digesting at high temperature, and under pressure, with caustic 
 soda. The lignone is resolved to alkali soluble derivatives. 
 In the case of coniferous woods, the following are the 
 general statistics of the resolution : 
 
 100 of lignocellulose are resolved into 
 (Insoluble) 35 cellulose ; 
 (Soluble) 65 lignone products of resolution. 
 
 The alkali - soluble derivatives present the following 
 characteristics and quantitative relations : 
 
 Carbonic Acid ra 
 
 Formic ,, yo 
 
 Acetic ,, 07 
 
 Lactonic Acids 32*6 
 
 Lignone 33'3 
 
 Ether-Soluble 25-2 
 
 100*0 
 
 (" Chem. Zusammensezung des Fichtenholzes," P. Klason. 
 Borntraeger, Berlin, 1911). 
 
 The proportion of soda neutralised is 20 per 100 parts 
 of the lignone complex. In practice, the caustic soda used 
 is approximately twice this proportion or about 15 to 20 
 per cent, of the original lignocellulose. 
 
21 
 
 Assuming that the caustic soda thus taken into work is 
 lost, the cost sheet of the process would present the following 
 main features : 
 
 Raw Material for i ton " soda " cellulose : pre- 
 pared wood ... ... 2'5 3'O tons. 
 
 Chemicals (Caustic Soda) 0-50-6 ton. 
 
 {Digestion Process } 
 Mechanical Treatment > i ton. 
 Cylinder drying of Pulp ) 
 Labour and Superintendence i 53. od. /i ics. od. 
 
 These are the general elementary factors of industrial 
 chemical processes. But there are important qualifying 
 factors which we may roughly set forth. 
 
 The Raw Material originally is a forest tree. As felled, it 
 contains excess of moisture, and in preparation for treatment 
 it is deprived of bark, sawn, and then chipped, and the chip 
 cleaned. For 2*5 3*0 tons of prepared wood, 4 5 tons of 
 forest wood are required, and the material has to be trans- 
 ported from the forest to the works. 
 
 Chemicals Soda Recovery. There is, of course, no loss 
 of alkali in the boiling process. The alkaline by-product 
 liquor is evaporated, and at suitable concentration is turned 
 into an incinerating furnace. The dissolved organic matter 
 has a high calorific value. As a useful constant to remember, 
 we may point out that a 12 per cent, solution of cane sugar 
 represents sufficient potential calories for its total evaporation. 
 The lignone by-products represent a higher calorific value 
 proportional to their higher carbon percentage. 
 
 Assuming that the wood is digested with twice its weight 
 of original solution, becoming yo 4-0 times its weight by 
 condensation of steam, in heating up and compensating for 
 cooling by radiation : the original by-product liquor would 
 represent a solution of 2 tons of by-product in, say, 8 10 tons 
 of soda solution, and obviously an excess of potential calories 
 
22 
 
 for total evaporation. A large proportion of the liquor can 
 obviously be removed at full strength. 
 
 But i ton of cellulose pulp when drained would retain, 
 say, 2 tons of the liquor. It is obvious that to displace this 
 we have to employ wash water. Washing is carried out to 
 the economic limit as between soda recoverable and water to 
 be evaporated. 
 
 Consequently, the item " caustic soda " is the cost of soda 
 in the form of " recovered soda," that is, the cost of evapora- 
 tion from original liquor plus washings, the cost of furnacing 
 and causticising the ash. To this is to be added the absolute 
 loss of soda, which in a series of operations will amount to 15 
 per cent. 
 
 For a full discussion of the practice of soda-recovery, which 
 is a fundamental problem of chemical engineering, we can 
 refer our audience to the excellent handbook of J. 
 Beveridge, " Paper- Maker's Pocket Book," London, 1911. 
 (McCorquodale.) 
 
 A further development of the economy of the alkali process 
 is based upon the deoxidation of sulphate of soda to sulphide 
 by the alkaline by-products of the boiling process. It is 
 evident that the absolute loss of soda can be made up by 
 addition of the equivalent of the neutral salt which in the 
 incineration would be reduced to sulphide being further in 
 part transformed to carbonate the sulphide having a hydro- 
 lytic efficiency but little inferior to the oxide (hydrate). An 
 extension, however, of this substitution enables us in a cycle 
 of operations to substitute entirely the salt or cheap sulphate 
 as source of alkali. 
 
 Taking sulphate of soda at i per ton, it is evident that 
 the theoretical value of Sodium Sulphide in this form is 363. a 
 ton, and under the conditions of its formation from the 
 sulphate by the deoxidising action of the dissolved organic 
 
23 
 
 matter, there is very little additional cost to be reckoned. On 
 the same basis the carbonate represents 273. 
 
 In actual practice the cycle is maintained on a basis of raw 
 materials as follows : 
 
 For 1,000 kilos pulp produced: 
 
 8-5 space-metres or 6 solid metres spruce wood. 
 
 160 kilos of Na 2 SO 4 and 350 kilos quick-lime and the ash 
 from the incinerator. 
 
 In the causticised ash liquor the average proportion of 
 active soda compounds is 
 
 Na 2 CO 3 12 grms. per litre. 
 NaOH 100 
 
 Na 2 S 26 
 
 Consumption of Fuel. An approximate figure for this 
 important item per ton pulp produced is : 
 
 In steam raising. For the digestion process for 3 tons steam Ibs. 
 (1,200 units per Ib.) at 90 Ibs. pressure 1,000 
 
 For drying pulp on cylinders for 1-5 tons 
 steam (1,150 units per Ib.) at 25 Ibs. 
 pressure ... 450 
 
 For evaporation of liquors. Additional to heat supplied by 
 
 combustion of by-products, 8 cwts.... 896 
 
 2,346 
 
 Labour and Superintendence. These items complete 
 the skeleton works' cost sheet and may be approximately 
 estimated at i 53. i los. per ton of pulp. 
 
 We have introduced these details rather as an illustration 
 of an important part of the work of a technical chemist, and to 
 point out to those who may not have considered such matters 
 from the point of view of a chemist's training, that they are 
 merely an extension of our ordinary practice of quantitative 
 analysis. 
 
 Resuming the main theme of our inquiry, we find that the 
 alkaline processes of cellulose isolation fulfil certain technical 
 ideals: yielding a main product of satisfactory quality, and 
 organic by-products which are also utilised in doing chemical 
 
24 
 
 work, and in effect the net result is an industrial process of a 
 high order of economic efficiency. 
 
 The objections to those processes are : there is a con- 
 siderable destruction of cellulose under the action of the 
 alkali, the yields of pulp are considerably below the maximum 
 of laboratory normal processes, and the attack of the active 
 agent or its result may be likened to a chemical debdde. 
 Reverting to our schematic formula for the lignone complex, 
 this ought to suggest to the student that a merely hydrolytic 
 attack must be of the most highly complex order, and as an 
 exercise of imagination, applied to the consideration of the 
 functions of a lignocellulose in nature, he will discover in the 
 complex a paradoxical union of sensitiveness and resistance to 
 the chemical influences of our planet. These are notably 
 water and oxygen under the very special conditions of energy 
 equilibrium following from the activity of life on the one hand, 
 and on the other, light, heat and electricity the forms 
 of energy with which we are familiar. The perennial individual 
 must be endowed with sensitiveness to meet the endless chain 
 of adaptations imposed by corporate organic existence, and 
 resistance as the obvious condition of permanence. 
 
 But the formula is based upon, and therefore might 
 suggest, specific reactions of characteristic groups. Two of 
 these are of especial interest and, though of very opposite 
 characteristics they have certain main features in common. 
 
 (i) They are quantitative and invariable; (2) while they 
 specifically modify a particular group, the lignone complex is 
 affected as a whole and converted into derivatives which 
 are soluble. These reactions are : 
 
 (i) Chlorination to a quinone chloride; (2) Combination 
 with bisulphite residues, in the first stage to an aldehyde- 
 bisulphite compound, leading, as a second stage, to sulphona- 
 tion, the entire lignone complex being obtained as a colloidal 
 sulphonate in solution. 
 
25 
 
 The latter reaction is the basis of the now well-known 
 industrial process of preparing cellulose (" bisulphite pulp ") 
 from coniferous woods, a process with which we may be said 
 to have grown up. 
 
 We only deal with this process in specific contrast to the 
 alkaline or soda processes. The solution employed is a 
 calcium bisulphite solution containing 3 per cent, of SO^ of 
 which one-third is combined with CaO (and MgO) in the ratio 
 M"O.SO 2 . The proportion by weight to the wood is 3-5 5-0, 
 according as the digestor is of the rotary or stationary type. 
 It may be assumed that the proportion of SO 2 required for 
 the actual reaction of synthesis is 10 per cent, of the pure 
 wood substance. From the excess of bisulphite solution 
 employed, one-third of the SO 2 is recovered by the simple 
 method of "blowing off" during the digestion and absorbing 
 after cooling, in the freshly-prepared bisulphite liquor. 
 
 In comparing the costs of this process with the alkaline 
 processes, it is evident that the main item of difference is the 
 cost of sulphur, which is lost in the form of sulphonated by- 
 product, compared with the cost of recovery of the soda of the 
 alkaline processes, plus the value of the soda beyond the limit 
 of economic recovery. 
 
 In the bisulphite process, moreover, the wood requires 
 selection and more careful preparation, the reaction upon 
 which it depends being obviously specific to lignocellulose ; 
 whereas the alkaline hydrolysis constitutes a universal attack 
 and decomposes bark, cuticular tissues, even knots, and denser 
 forms of lignocellulose. 
 
 The prepared wood for this process may be taken at 
 $ 155. "4 per ton of pulp. The cost of sulphur combined 
 in by-product liquor and therefore lost, at 5 per cent, on the 
 wood, say 12-5 per cent, on the pulp, and with incidental costs 
 of conversion into bisulphite, approximately i per ton. 
 
26 
 
 Finally, we note that the differences of costs of production 
 are reflected in the market prices of the products, " soda " 
 and " sulphate " pulps ruling at an average of j a ton ; 
 " sulphite " pulps at /"8 g. 
 
 As our concluding illustration we have to consider the first 
 of our characteristic quantitative reactions that between the 
 lignone complex and chlorine as the basis of a possible 
 industrial process. 
 
 As we are taking an ideal case as distinct from an 
 industrial actuality, we will take the " academic licence " of 
 simplifying the problem in terms of the simplest type of 
 lignocellulose, which is the jute fibre. 
 
 This fibre substance reacts in the cold with chlorine, 
 combining with 8 per cent, of its weight as lignone-chloride, 
 and forming an equivalent proportion of hydrochloric acid. 
 
 Allowing for unavoidable losses, it appears therefore that 
 100 parts of jute lignocellulose can be resolved by treatment 
 with 20 parts of chlorine. 
 
 Of the products of reaction we may take the lignone 
 chloride as of no value. It is soluble in alkalis and would be 
 so removed from the cellulose, obtained as a pulp, or mass of 
 disintegrated ultimate fibres. 
 
 But the hydrochloric acid has a value, and it is one of the 
 paradoxes of chemical industry that evolution brings about a 
 partial inversion of primary values ; thus hydrochloric acid 
 comes to have in certain circumstances a value superior to 
 that of the element. In evidence of this point, we refer to a 
 recent paper in the " Chemiker Zeitung," 1912, 36, p. 54, " Zur 
 Herstelling von Salzsaure aus Chlor," which, by the way, 
 sounds like travelling from London to Paris via Berlin. 
 Without discussing the complex equilibrium of the alkali 
 industry, it is general knowledge that the displacement of the 
 Leblanc by the Solvay soda process on the one hand 
 which cuts the production of HC1 and by electrolytic 
 
27 
 
 processes, on the other which means a relative over- 
 production of chlorine must involve a modification of the 
 theoretical ratio of values Cl : HC1. The author of 
 the above paper O. Nagel proposes a reaction with 
 water vapour and carbon at high temperature, thus : 
 Cl 2 +H a O + C==CO + 2HCl, for the industrial production of 
 the acid. 
 
 It would appear, therefore, that a cellulose process based 
 upon consumption of chlorine, with production of HC1 as a 
 by-product, might also contribute to remove an artificial 
 industrial congestion. 
 
 Apart from this, in the first place, our present problem is 
 the cost of treating jute fibre with 20 per cent, of its weight of 
 chlorine. What are we to take as the value of chlorine ? 
 
 A theoretical maximum value is indicated by the current 
 market price of bleaching powder. Taking this at 925., and 
 
 at 37 per cent. " chlorine," the value is = 2485. or 
 
 12 8s. The value at the centre of production is obviously 
 less by the costs of conversion into bleaching powder, packing 
 and transport. If, however, we electrolysed sodium chloride 
 we should require to decompose 
 
 = 35 kilos of common salt to treat 100 kilos of 
 
 jute fibre, and with the 20 of chlorine we should obtain 
 
 t O V O(~) 
 
 = 30 of Na 2 CO 3 (Hargr eaves- Bird process), or 26 of 
 NaOH (Castner-Kellner process). 
 
 In an ordinarily efficient electrolyser, steam power, repre- 
 sented by 5 k.w. hours, should produce i kilo chlorine, i.e. t 
 under favourable conditions, for 2d., together with the equiva- 
 lent of soda compounds in solution. To this figure we have to 
 add cost of raw material, labour, upkeep of electrolytic plant 
 and general costs. 
 
We now turn to the actual process of resolving the ligno- 
 cellulose. (100 Kilos.) 
 
 Taking jute butts or root ends, they require an open 
 boiling with an alkali say 5 per cent, of their weight of caustic 
 soda. This would be furnished as a fifth of the alternative 
 products of electrolysis. 
 
 The fibre boiled, washed, and squeezed to hold its own 
 weight of water is exposed to the electrolytic chlorine till 
 fully chlorinated. 
 
 The HC1 formed is removed by systematic washing. 
 Adding 300 litres of water and removing 300, we recover 6 
 kilos HG1 in 2 per cent, solution, adding 700 litres and 
 removing 700, we obtain 7 kilos HC1 in i par cent, solution. 
 
 Removing the residue of acid at a dilution beyond a useful 
 or economic limit, the chlorinated fibre is then treated with 
 electrolytic alkali in dilute solution, using 10 per cent, of its 
 weight. After washing from the by-products thus dissolved, 
 the cellulose is obtained as a pulp. 
 
 A preliminary theoretical cost sheet of materials employed 
 in the treatment is made up as follows : 
 
 To yield 100 kilos of alkali-boiled and purified jute ligno- 
 cellulose, we require 120 kilos of raw material, which at 12 
 per ton (1,000 kilos) represents 295. 
 
 We have used of electrolytic products costing, say, 43., the 
 whole of the chlorine, and three-fifths of the alkaline pro- 
 ducts: to obtain, say, 75 kilos jute (cellulose) half-stuff or pulp. 
 
 As a set-off we have 6-7 kilos of HC1 in the form of acid 
 liquid, dilute and impure from the presence of some organic 
 matter dissolved from the chlorinated fibre, together with the 
 surplus of electrolytic soda. Presuming a use for such pro- 
 ducts, and estimating their value at one-half the cost of 
 obtaining them by dissolving or diluting the ordinary com- 
 mercial products, we might reduce the item of 45. to 33. 6d. 
 
29 
 
 To treat i ton of boiled raw material, represented by 
 1,200 kilos of original raw material, the chemicals required are 
 thus in the neighbourhood of 453. per ton of half-stuff. The 
 further costs are those of steam for the boiling and for power 
 consumed in incidental mechanical operations : and, lastly, 
 labour and superintendence, which would bring the total cost 
 to, say, ^"24 per ton. With jute at present prices such a cost 
 would be prohibitive. But we have selected jute merely as a 
 chemical type. In our earlier days jute cuttings had a very 
 different market value, viz., 5 6 per ton, and a process on 
 these lines would have had an industrial outlook. 
 
 We must plead the exigencies and limitations of a lecture 
 as our reason for merely sketching the theoretical features of 
 the industrial exploitation of a laboratory reaction. We con- 
 clude with an actual demonstration of the operations incidental 
 to the treatment of 120 grams of material, and a very important 
 result of experience, viz., that the cellulose chemist is expected 
 to estimate very closely from observations on 100 grams of 
 material what the factory working will show with 100 tons. 
 
30 
 
 APPROXIMATE STATISTICS. 
 The following diagrams were used in illustration. 
 
 U.K. ANNUAL TRADE IN CELLULOSE PRODUCTS AND 
 DERIVATIVES. 
 
 Production. 
 Cotton manufactures ... ... ... ... ^125,000,000 
 
 Linen, hemp jute 19,000,000 
 
 Rope, twine, net ... ... ... ... 3,500,000 
 
 Cocoa fibre, straw hat, and miscellaneous ... 2,000,000 
 
 Paper and boards 13,500,000 
 
 Special industries, cellulose derivatives, 
 
 explosives, celluloid, and artificial silk 3,000,000 
 
 Coal, 260,000,000 tons, say 150,000,000 
 
 CHEMICAL MANUFACTURES. 
 
 Total production, United Kingdom ^"23,740,000 
 
 Germany 62,500,000 
 
 Aniline, \ German exports, total 8,000,000 
 
 anthracene 
 
 dyes & indigo / * wmcn to United Kingdom 1,700,000 
 
 Percentage-ratio of chemical manufactures to total trade. 
 
 United Kingdom. Germany. 
 
 Imports 1-5 ... 4-5 
 
 Exports 4-5 ... 9-5 
 
 [E. F. Hooper "Some Aspects of Chemical Trade"/. Soc. Chem. Ind., 
 31, p. 7, 1912.] 
 
31 
 
 Schematic Formula. Lignone complex (jute lignocellulose) 
 approximately C 20 H 22 O 10 . 
 
 A B CD 
 
 O O /O^ 
 
 H/NH - [CH 2 . CO] 2 -Hf \H.CH. CH. CH gg | 
 
 H x 
 
 Lignone. Cellulose. 
 
 Constituent Groups. Quantitative Diagnosis. 
 
 A Benzenoid Chlorination to C 19 H 18 C1 4 O 9 
 
 and reactions of Cl : deriva- 
 tives. 
 
 B Ketene Acetic acid by hydrolysis, oxi- 
 
 dation and destructive distil- 
 lation. 
 
 C Pyrone or Hydropyrone Production of acetone and 
 
 maltol ; various reactions. 
 
 D Side chain : Aldehydic Reaction with bisulphites and 
 
 production of lignone sulpho- 
 nates. 
 
 Methoxyl Estimation. Zeisel method. 
 
32 
 
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33 
 
 Lecture II. 
 
 Having in our first brief survey of the field of cellulose, 
 taken a few prominent examples of industrial problems as 
 illustrations of principles, we revert to our main theme, which 
 is colloidal matter, or the colloidal state, of which cellulose is 
 the obvious prototype. 
 
 It will be useful to give a few practical demonstrations 
 of colloids, in their various moods and tenses, not only for 
 their detached interest as striking forms of matter, but to 
 present these types as an evolutionary series in progressive 
 development of properties which culminate in cellulose. 
 
 A familiar case of a transitional colloid that is rapidly 
 passing from the colloidal to the crystalline form, is calcium 
 carbonate in its hydrated state, resulting from double decom- 
 position, as in the preparation of sodium from calcium 
 hypochlorite according to the simple reaction : 
 
 Bleaching powder solution I CaCl2 
 
 1 
 
 Ca(OCl) 2 Na a C0 3 . 
 On mixing solutions of equivalent concentration, solidifica- 
 tion takes place. We may assume that we have a complex of 
 all the active groups with very great hydration capacity : a 
 phase of synthesis. Cleavage then asserts itself, with 
 reversion to the simpler molecular forms : the calcium 
 carbonate, as a dehydrated crystalline body, now occupying its 
 normally small volume. It is quite probable that this is a 
 very general characteristic of reaction, and that the colloidal 
 phase represents a synthetic complex with an interior unstable 
 equilibrium of affinities. The colloids we shall consider are 
 
 C 
 
34 
 
 all complex polyhydroxy compounds, and of these compounds, 
 whether inorganic or organic, it is generally true that the 
 OH groups are of variable function, which, at the extreme 
 of divergence, represents a polar opposition, or, in our ordinary 
 terminology, the opposition of base and acid. Alumina is an 
 obvious case ; and in silica we can easily demonstrate that 
 one of the OH groups manifests basic properties. 
 
 We show the simple experiment of adding to a solution of 
 sodium silicate, hydrochloric acid one-tenth less and one-tenth 
 more than equivalent to the soda. The former sets to a " gel," 
 the latter remains fluid, through formation of a saline chloride 
 or hydrochloride. This observation is due to Prof. Jordis, of 
 Erlangen. 
 
 In the carbohydrates, the development of polarity, or 
 amphoteric opposition, may be referred to characteristic 
 constituent groups of Ketene or CO CH 2 configuration, this 
 labile and somewhat elusive complex, which appears as a 
 factor of constitution of many groups of carbon compounds. 
 As to the potentialities of this " diatom," we refer our audience 
 to a highly instructive and suggestive paper by our Chairman 
 [" Derivatives of the Multiple Ketene Group." J. Norman 
 Collie Chem. Soc. /., 91, p. 1806 (1907.) ] 
 
 Starch, which we have taken as a type of colloid, occupies 
 a unique position, whether considered from the point of view 
 of organic function, industrial utility, which is largely the 
 fulfilment of its organic function in relation to animal life, or 
 its special chemistry. We must presume acquaintance with 
 all that defines its special position in the world of matter 
 and science, since for obvious reasons we can only call atten- 
 tion to certain of its particular characteristics. 
 
 Occurring in specialised forms, its colloidal " habit" is 
 particularly manifested in the phenomena of its hydration, 
 the swelling and bursting of the granule in contact with water 
 at specific temperatures to a state of pseudo solution, the 
 
35 
 
 familiar starch paste. This may be regarded as a distension, 
 ad infinitum, of the starch granule, presenting in the aggre- 
 gate a complex of phases ; consequently, on drying a starch 
 paste, there is a diversity of reversion phases, producing a 
 discontinuous solid residue, with more or less of the structure 
 of the original granule. 
 
 Hence, in many of the industrial uses of starch, e.g., as a 
 " finishing " agent for textiles, there is an evident cause of 
 low efficiency. For it is manifest per contra that the true colloid 
 is one that is homogeneous throughout its solution phases, and in 
 reverting, by loss of solvent, maintains that continuity of mass 
 which, in thin layers, produces a transparent film. 
 
 It is common knowledge that starch is extremely sensitive 
 to acids, and alkalis, and, even though a " saturated " body, to 
 oxidants ; and by various treatments with these reagents, is 
 modified to " soluble starches," in which there is an approxi- 
 mation to the true colloid as above defined. Without 
 attempting to describe or compare these numerous products, 
 we call attention to one with which we are familiar, produced by 
 interaction of dry starch with glacial acetic acid. This action 
 results in partial acetylation and an attack on the starch 
 complex or aggregate, which may be controlled to produce a 
 range of definite variations of the essential colloidal proper- 
 ties. These products known as " Feculose " are employed 
 in industry for various purposes and, in accordance with 
 requirements, they may be prepared so as to yield true 
 solutions of high concentration, e.g., up to 25 per cent., which 
 may be either permanent, or revert to a gel when the 
 originally hot solution is allowed to cool. 
 
 Specimens of such Feculose solutions are submitted, 
 comparatively with pseudo solutions of starch produced under 
 similar conditions. It is well known, however, that the limits 
 of fluidity of starch pastes from ordinary starches and 
 modified starches is reached at 5 10 per cent, concentration. 
 
 c 2 
 
36 
 
 The most important use of Feculose one of many is in 
 paper coating, that is, the surface filling of papers to be used 
 as the basis of mechanical prints. In producing these " art 
 papers," a white inert pigment is suspended in a colloidal 
 medium, e.g., gelatin, or casein solution, and the mixture is 
 applied to the paper surface by rollers, followed by a brush- 
 ing treatment to complete the even distribution of the coating. 
 The paper thus coated is carried forward and hung in festoons 
 in a drying-room, and is reeled off continuously at the end 
 of its travel, to be finally surfaced by calendering. 
 
 Feculose in this industry replaces casein, weight for 
 weight, and gelatin of best quality in the proportion of 5:4, 
 with the advantages (i) of being a colourless and nitrogen-free 
 solid, and (2) that high temperatures can be used in drying. 
 
 This is a useful, practical example of the industrial colloid, 
 and the appreciation of colloidal quality by chemical treat- 
 ment. For the scientific account of these products we refer 
 to : " Die niederen Acetylderivate der Starke und Cellulose " 
 Cross, Bevan and Traquair, Chem. Ztg., 29 (1905). 
 
 Starch is to the biologist the first visible product of assimi- 
 lation in the plant cell, but its main function is that of reserve 
 material stored in the seed endosperm to supply nutrient 
 material for transformation by the germinating embryo ; to the 
 chemist it is a polyhexose anhydride, and by reason of its 
 hydrolysis to sugars, the basis of the fermentation industries, 
 that government-ridden section of chemical industry ! 
 
 Proceeding upward in the chemical scale, we have now to 
 mention a group of plant products, also conspicuous and 
 widely distributed as constituents of seed endosperms, which 
 may be classed as hemi-celluloses. This term indicates a 
 genetic relationship of the bodies to cellulose, which may or may 
 not be actual : we are only concerned to demonstrate that 
 their properties are intermediate between those of starch and 
 cellulose. 
 
37 
 
 As a type, we take the endosperms of the locust bean 
 (Ceratonia Siliqua), and show specimens of the following 
 stages of treatment : (a) separation of endosperms from 
 cotyledons on the one hand, and external protecting tissues on 
 the other, i.e., the proximate resolution of the seeds into 
 component tissue ; (6) digestion of endosperms with water at 
 90 100, and progressive hydration to the condition of a " gel," 
 or pseudo solution, in which, at 3 to 4 per cent, strength, it is 
 an industrial product known as " Tragasol." 
 
 The actual constituents of this " gel," according to the 
 exhaustive researches of E. Bourquelot, are in the main 
 mannan and galactan, the anhydride form of the hexoses 
 mannoss and galactose, in the proportion of 4:1. According 
 to our own observations, the proportion of galactose is usually 
 somewhat lower, viz., from 10 to 15 per cent. 
 
 The elementary composition of the complex we have 
 determined as follows : 
 
 (a) Composition of total solids. 
 
 (6) Composition of solids precipitated by alcohol. 
 
 (a) (6) 
 
 Carbon 42-40 ... 43-50 
 
 Hydrogen 5-98 ... 5-90 
 
 which numbers conform with the general distinction in this 
 group between hydration and hydrolysis : hydration of the 
 anhydrides proceeds to indefinite limits without determining 
 hydrolysis. These hemi-celluloses are in effect resistant to 
 enzyme hydrolysis, but are readily attacked by acids and 
 alkalis. 
 
 The industrial uses of tragasol are conditioned by these 
 properties, together with the most important property of 
 reverting to a continuous solid, that is a translucent film. 
 Specimens of the tragasol film are submitted, showing an 
 apparently fibrous structure due to considerable residues of 
 the original cellular structures of the hemi-cellulose, drawn 
 out by manipulation of the viscous " gel." 
 
38 
 
 The precipitation of these hemi-cellulose hydrates by tannic 
 acid yields a new colloid of remarkable properties. 
 
 Taking for the mannan-galactan complex the formula 
 CujHaaOn, and for tannic acid C 14 H 10 O 9 , combination takes 
 place approximately in the ratio of the formula-weights ; the 
 following numbers having been obtained for the elementary 
 composition of the precipitated compound : 
 
 Carbon 47-3 
 
 Hydrogen 4-4 
 
 The new colloid, termed " Cutiloid," insoluble in cold water, 
 separates as a massive homogeneous curd, representing 
 5 6 per cent, of solid contents. On slightly raising the 
 temperature, i.e., to 40 50 C., the mass changes from a white 
 coagulum to a transparent homogeneous solution with an 
 enormous increase of viscosity: the change is comparable 
 in sharpness with the bursting point of starch granules at 
 6070 C. under similar conditions of heating, but with the 
 difference that the phenomena are reversible. 
 
 The properties of the new colloid mark it out for various 
 industrial applications, which will be evident. 
 
 Most characteristic are its reactions with gelatin. The 
 reactions of tannic acid with gelatin, and the colloids of animal 
 skin, are well-known : by the previous combination of tannic 
 acid with the complex carbohydrates, its interaction with 
 gelatin is entirely changed. Highly complex colloidal bodies 
 result, but without separation from solution. Hence the 
 application of cutiloid as a tanning agent. 
 
 The tanning by " Cutiloid " may be shortly described as a 
 restrained effect, and practical experience has shown that by 
 thus restraining and modifying the attack of tannic acid, it is 
 possible to carry on the tanning process with great rapidity, 
 and without detriment to the product. This is a feature of 
 colloid phenomena which has its parallel in the well-known 
 practice of the silk-dyer. The avidity of silk for colouring 
 
39 
 
 matters is so considerable and general that it would be 
 impossible to dye silk evenly in the skein or mass by the 
 ordinary practice of a dyeing bath, unless the intensity 
 of interaction were restrained. This is effected in practice by 
 using in place of water as the medium, the solution obtained 
 by neutralising the liquors used in degumming the silk. 
 These are soap solutions, and, after boiling with the raw silk, 
 contain its hydrolysable colloids in solution. On neutralising 
 with acid, there is formed a complex colloidal emulsion, and 
 the colouring matters enter into intermediate combination 
 with the components of the emulsion, through which they are 
 taken up by the silk substance at a very much reduced rate, 
 and for obvious reasons. 
 
 Before we leave this group of hemi-cellulose colloids we 
 mention another product which has considerable interest. 
 
 This is known as "Japanese Isinglass,"* or more generally 
 as Agar-Agar. The preparation of colloids, from edible sea- 
 weeds, e.g., Calidium Lamouroux, is a characteristic Japanese 
 industry, and occupies about 70 villages on the coast provinces 
 of Yamashiri-Tanba, Setsou, and Shinane. It is a steadily 
 
 * There is some doubt as to the identity of this particular specimen, a 
 portion of a large exhibit at the recent Anglo-Japanese Exhibition. Its 
 general characteristics are those of Agar-Agar, which is the Malayan name 
 (" sea-weed ") for Gracilaria lichenoides (G. Birdwood, Jour. Royal Soc. Arts, 
 60-439). The percentage of galactose estimated is lower than the 33 per 
 cent, usually accepted for Agar-Agar. (Konig and Bettels, " Chem. 
 Centralblatt " : 1905, ii., 1606.) The low yield of furfural (and methyl 
 furfural) appears to exclude cellulosines of laminaria. It is also doubtful 
 whether the above description of an industry does not rather apply to the 
 " Nori," a popular foodstuff in Japan, obtained from Porphyria Laciniata. 
 
 The point, however, is not material, the substance being a typical 
 cellulosine of the second group, as distinct from the first, which are those 
 of seed endosperms, and a large Japanese industry in such products 
 actually existing. 
 
 For a full account of these characteristic colloids see " Biochemisches 
 Handlexikon" (E. Abderhalden), Vol. 2. Springer, Berlin, 1911. 
 
40 
 
 increasing industry, and the value of the exports for 1910 was 
 16,000,000 yen (i yen = 2s. ojd.). Most of this is exported to 
 China, where it is consumed as food. 
 
 Specimens of this product are exhibited, and we demonstrate 
 its characteristic relationships to water. A 2 per cent, solution 
 reverts on cooling to a firm structureless jelly. From this we 
 have prepared the reverted product in transparent film. We 
 have investigated this colloid, with others of the same class, 
 and we may mention its approximate characteristics as 
 
 follows : 
 
 Moisture (air dry) 22*9 
 
 Ash ... 2-9 
 
 Albuminoids ... 0*91 
 
 Furfuroids 2-5 calculated from 
 
 the yield of furfural i'2 / 
 
 The most characteristic constituent is galactan carbo- 
 hydrate, which we estimated at 25-0 per cent. It is to be 
 noted that this product has a limited sale in this country, 
 at a wholesale price of is. 6d. per lb., c.i.f. London. Its 
 chief consumption is in the preparation of cultural media 
 in bacteriological research. 
 
 It will be evident that these are not merely types selected at 
 random, but naturally or artificially selected, each as a basis of 
 industry. It is not to be affirmed that this selection is finally 
 exclusive; it is certainly true that throughout the natural 
 world there are vast numbers of these colloidal substances 
 presenting altogether special properties, and in the future the 
 science will use this material in formally attacking the problem 
 of the causal relationship of structure to constitution, which 
 problem is for obvious reasons more directly suggested and 
 defined by the natural and industrial function of cellulose. 
 
 The colloidal characteristics of cellulose are conspicuous 
 in all those reactions which result in a soluble product. 
 
 Though we limit ourselves in this exposition to the cellu- 
 lose-water series, we just note that the higher synthetical 
 derivatives, the cellulose esters, soluble in specific solvents, 
 
41 
 
 present a closely similar range of properties, notably gelatini- 
 sation by the solvent as the first stage, then solution to a more 
 or less homogeneous fluid of high but variable viscosity, and a 
 working maximum of filterable solutions at 7 8 per cent, 
 cellulose. 
 
 Hence it is immediately clear that the specific colloidal 
 characteristics of cellulose are not bound up with its OH 
 groups, and this gives a first suggestion that these properties 
 have a more deeply-seated cause and origin than the condition 
 of proximate constitution or molecular aggregation. 
 
 Cellulose presents us with a bewildering complexity of 
 forms and degrees of hydration, of which we first demonstrate 
 some conspicuous examples, connecting cellulose with the 
 colloids previously described. 
 
 Cellulose and Zinc Chloride. The hydration of cellulose 
 by zinc chloride (50 / ZnCl 2 Aq), at 60 70 C., proceeds in 
 unbroken continuity to the maximum represented by solution. 
 The aqueous solution at i 2 per cent, concentration (cellu- 
 lose), limpid and viscous at 60, reverts on cooling to a firm 
 homogeneous gel. 
 
 The reactions involved in this series of phenomena are, 
 chemically speaking, obviously of the simplest, and suggest 
 that cellulose interacts as an amphoteric complex, that is, 
 reciprocally, with acid and basic groups of the metallic salt. 
 
 Cellulose. Alkaline Hydrate Carbon Disulphide. These 
 are stages in the now well known and often described 
 " Viscose " reaction, and we demonstrate an extended series 
 of these products, including those of reversion from the fluid 
 stage by spontaneous decomposition of the xanthogenic ester. 
 
 It will be noted that the first product, alkali-cellulose, 
 which has the percentage composition 
 
 Cellulose 25 NaOH 12 Water 63 
 
 represents considerable hydration of the cellulose, with which 
 are associated large modifications in the structure of the fibre. 
 
42 
 
 After reaction with the bisulphide, the new ester, as Na 
 salt, has a great avidity for water. We demonstrate this 
 combining capacity by the reaction in which we substitute a 
 lignocellulose. 
 
 The association of the cellulose and lignone groups some- 
 what modifies the reaction. It will be noticed that as we 
 proceed to treat with water the reaction product from 5 grams 
 original jute, there is an enormous and progressive distension 
 of the fibres, and we obtain a colloidal sponge occupying some 
 1,000 c.c. To this we add acetic acid, which at once attacks 
 the coloured alkaline by-products, but which only slowly 
 attacks the xanthate soda. We hasten the reversion, which, to 
 take place spontaneously, requires a lengthened period, and we 
 have a complete restoration of the original fibrous structure. 
 We may regard this extreme distension as the penultimate 
 stage of hydration of cellulose with the structure persisting. 
 It is impossible to draw any line between this phase and the 
 ultimate condition of a structureless solution, if indeed any 
 such can be prepared. The demonstration is an ocular one of 
 the continuity of the solution and reversion phases, which 
 condition the important industrial uses of these derivatives. 
 
 Less obvious than these extreme cases are the partial 
 hydrations which accompany and condition the processes of 
 the papermaker. 
 
 The mechanical process of " beating " fibrous materials has 
 the two functions, the reduction to uniform and convenient 
 length (2 3 mm.), and the production of a condition of the pulp 
 which affects its suspension in the carrying medium, which is 
 water, and determines a graduated sedimentation as it parts 
 with water, through the sieve or continuously running wire of 
 the papermaking machine. That this condition of the pulp of 
 cellulose is, or involves, hydration, will be easily recognised 
 when the beating process has been prolonged to 24 36 hours. 
 The product then is recognised as a hydrated colloid, and, 
 
43 
 
 when allowed to dry in masses, these finish as a coherent 
 aggregate, to which the term " cellulith " is applied. 
 
 In the earlier stages of beating, the effects of hydration are 
 empirically recognised in the terminology of the "beatermen" ; 
 the stuff in process develops " wetness " or " greasiness." 
 
 The complex of effects produced in the beater are now the 
 object of analytical study, and of inventions designed to 
 separate and control the various factors, notably that of hydra- 
 tion. Mr. H. Jackson, of Garstang, Lanes., papermaker, 
 adopting fundamental views of his raw materials as colloids, 
 and of colloidal quality that it is a variable to be controlled 
 and is measured by hydration capacity, has invented a beating 
 engine designed especially to give maximum hydration effects 
 in minimum time. The mechanical principle of the new beater 
 is a " wet hammering " of the fibres, effected by actual 
 hammers operating centrifugally, so that the force of the 
 blows will vary with the speed of rotation. 
 
 We could very well occupy an entire lecture in discussing 
 the problems of this section of cellulose technology. It 
 must suffice to demonstrate a series of products showing the 
 graduated development of the more obvious colloidal character- 
 istics with progressive hydration, up to extreme products in 
 gelatinous forms, which revert on desiccation and dehydration 
 to coherent solids : these can be turned and polished, being, 
 in fact, aggregates of fibrous residues embedded in relatively 
 structureless colloidal cellulose. 
 
 These effects of hydration are not only positive factors of 
 the first order of the structural qualities of paper and boards, 
 but they play their part in the process of sizing, by which 
 these products are rendered relatively water and ink-resistant. 
 It would take us too far afield to introduce a technical 
 discussion of the process of " engine sizing " by means of 
 rosin. If we merely state a typical case, we shall direct 
 attention to a technical principle involved in the result. 
 
44 
 
 One hundred parts of fibrous cellulose, beaten with 2,500 
 parts water, receive, as sizing agent, 2 4 parts rosin in 
 solution as soda-rosin soap, to be decomposed by sulphate of 
 alumina in excess. Now it is assumed in the text-books that 
 the sizing effect produced is the result of double decomposition 
 between the reagents, and deposition of the precipitated 
 resinate as a coating of the fibres the latter, therefore, a 
 purely mechanical effect, the cellulose being inert. A little 
 consideration will show that this view is superficial ; what is 
 involved is a complex equilibrium (i) as between cellulose 
 plus cellulose hydrates, and soda resinate in highly dilute 
 solution, say i/iooo ; (2) as between the products of interaction 
 under (i) and sulphate of alumina. That is a final equilibrium 
 as between cellulose to be regarded as a colloidal hydroxide, 
 of amphoteric character : alumina, which may be described 
 in the same terms, and the resin acid (abietic acid). 
 
 This problem is essentially a problem of colloidal 
 chemistry, as, indeed, are all the mill operations of the paper- 
 maker. 
 
 The process is the subject of considerable difference of 
 opinion amongst technologists, as to the actual effective sizing 
 compound, and divergent practice as to employing rosin sizes 
 of "neutral" or "acid" composition. 
 
 There are in effect several systems of acid sizing, that is, 
 based upon a rosin size containing 20 40 per cent, of free or 
 uncombined resin acid : systems which claim to economise 
 from 20 33 per cent, of the sizing costs, and are industrially 
 exploited on this basis. 
 
 But in this controversy the cellulose has been left out of 
 consideration, as the inert recipient of an added effect. The 
 contribution of hydrated colloidal cellulose from the beating 
 operations is also generally ignored. 
 
 It is clear to us, and we suggest to our younger 
 technologists, that in these primary and secondary factors 
 
45 
 
 of value of paper and boards, there are margins of value 
 which are largely ignored. 
 
 If we can only get our manufacturers to recognise clearly 
 that of the primary group, the values of the fibrous raw 
 
 minus 
 materials are the commercial or actual cost, , s say 303. a 
 
 ton, and in the secondary group, the value of rosin (in sizing) 
 
 minus . ,. 
 
 is its commercial cost, j^- 35. (per ton of paper), and that 
 
 it is the function of the trained chemist to use his abilities in 
 this field of margins towards controlling their incidence on the 
 plus side, we shall have done something for technical progress. 
 
 On this question of rosin-sizing we refer to a recent 
 experimental investigation of Remington, Bowack and 
 Davidson, printed in J. Ind. Eng. Chem., iii., No. 7 (1911). 
 
 The phenomena of engine-sizing thus briefly discussed are 
 of the same order as those processes of dyeing and colouring 
 which in the main are accessory to the textile and paper 
 industries. We have no intention of entering upon this 
 territory further than to point out that for the routine of 
 industrial work in cellulose, a study of the practice and 
 theoretical principles of dyeing is a necessary equipment. 
 
 But if beyond this the chemist is attracted as a contributor 
 to the literature of the theories of dyeing, we would enjoin a 
 severely critical programme of research ; and above all to be 
 critically selective of really typical cases, whether in the fibre 
 substance taken for experiment, or the colouring matter to be 
 studied. 
 
 It is to be observed that, as regards the latter, there always 
 has existed a wealth of material, that is of compounds con- 
 stitutionally defined ; and in the region of " Cellulose," we now 
 have an accumulation of definitely varied derivatives, not only 
 as regards chemical constitution, but also in regard to minute 
 structure and dimensions. 
 
46 
 
 Lastly, there are features in the actual dyeing processes, 
 as in the product which may be selected as typical, such as 
 in the interaction of lignocelluloses and ferric ferricyanide. 
 
 These reactions admit of demonstration, and we show the 
 process of dyeing jute with 10 20 and 30 per cent, its weight 
 of the blue cyanides, by simple immersion in the solution of 
 the red cyanide. The typical features of this are the large 
 proportions of cyanide taken up, without affecting the external 
 characteristics of the fibre ; accompanying this unusual 
 combination and interpenetration of two colloids, there is a 
 rearrangement of groups, with transference of oxygen to the 
 unsaturated lignone groups, and production of ferroso ferric 
 cyanides. 
 
 It will have been observed that, throughout this brief 
 exposition of the main aspects of " Cellulose," questions 
 of structure are always present. The structural cycle is in 
 fact this : we only know the raw material in the specialised 
 forms of the plant world, fibres and cells ; by mechanical 
 devices we can destroy the form more or less with little 
 change of substance ; by chemical means, i.e. } by reaction, we 
 advance another stage, viz., to that of structureless solution, 
 but with certain constitutional modifications of the cellulose ; 
 from these solutions we can revert to the solid form, and by 
 suitable means produce thread, film, or massive solids. 
 
 These artificial forms of cellulose in continuous length are 
 of regular or controlled dimensions, and hence it is evident 
 that throughout the entire cycle, structural problems move 
 hand-in-hand with molecular changes which we, of course, 
 can only visualise by theory and imagination. At present the 
 connection between these complementary phenomena is an 
 empirical one, but we cannot doubt that the progress of 
 research will establish the causal relations in quantitative 
 terms. 
 
47 
 
 It is obviously necessary for the chemist entering this field 
 to master the general principles of histological research; 
 questions of minute structure and dimensions are at the root 
 of practice in the textile and papermaking industries, and 
 problems involving measurements even in the ultra visual 
 region are as numerous as daisies, in the field of colloids. 
 
 The study of structure and minute dimensions in this field 
 has originated and developed rather on an empirical technical 
 basis. The transition to a scientific use of the data furnished 
 by these methods is a direct one. Thus, as an illustration : for 
 the artificial fibres considered as regular cylinders, we may 
 take the surface as the product of length by perimeter of sections, 
 i.e., 1 TT D, and surface varies with diameter. In the finer 
 threads or " silks " the unit filament presents about i Cm 2 of 
 surface per metre of length; or the textile thread 14 17 
 times this surface. Taking a reaction, depending primarily 
 upon surface, an investigation of the rate of combination of 
 the dehydrated product with atmospheric moisture, may 
 therefore be directed to the rate per unit of surface. Threads 
 of any required diameter being prepared may be compared on 
 this basis ; and, moreover, the masses of such threads varying 
 as the square of diameter, we can thus establish in numerical 
 terms the mechanism of communication of the hydration 
 effect from the surface inwards. From such data it would be 
 possible to arrive at a measure of the exterior surface of 
 natural fibrous celluloses, e.g., cotton, of irregular and variable 
 form. 
 
 The ratio of surface to mass is generally assumed to be 
 specifically characteristic of colloids, but the conception is 
 applied in this sense to the unit masses, molecules, or poly- 
 molecules of the colloids, i.e., as chemical individuals. A 
 study of the grosser relationships of the visible forms of 
 matter in this order of idea may very well lead to speculative 
 
48 
 
 treatment of the more fundamental constants, and, by means 
 of reactions, to some relative measure of the reacting unit. 
 
 But apart from remote speculation, a whole field of work 
 is waiting to be ploughed by standard physical methods, and 
 sown with seed of established ideas and conceptions. Thus, 
 specific volumes, solution volumes, volumes in relation to 
 temperature observed in media with and without presumed 
 interaction with the celluloses, and even the fundamental con- 
 stants of specific heat, have not been seriously studied in this 
 region of celluloses, cellulose derivatives and compound 
 celluloses. 
 
 And, as we have endeavoured to show by demonstrations 
 of allied forms of matter as particular variants of colloidal 
 matter, such physical methods may be extended to include a 
 graduated series of colloids having very definite connecting 
 links with the simpler forms of matter for which physical 
 constants are in effect measures of the reaction unit, or 
 molecule, according to the fully established generalisations of 
 the science. 
 
 From cellulose in relation to science, we revert in conclu- 
 sion to the question of its economic basis and relationships. 
 
 The world's supplies of cellulose are divided between : 
 (i) " crop plants," annuals under cultivation primarily for fibre, 
 but yielding secondary products of very great value, of which 
 we need only specify cotton-seed, flax-seed, and (2) perennial 
 woods, which furnish the staple raw material of the paper 
 industry. 
 
 In either group there are economic problems of great 
 magnitude, whether in the region of primary supply in relation 
 to consumption, or affecting the secondary element of value in 
 the possible utilisation of waste products. 
 
49 
 
 A concise handling of some of these problems will be 
 found in a recent publication of the U.S. Department of 
 Agriculture, " Crop Plants for Papermaking " (C. J. Brand), 
 1911. 
 
 Of present waste materials potentially available, this 
 brochure mentions, 
 
 Cornstalks 30,000,000 tons, 
 
 Rice straw ... ... 1,500,000 
 
 also flax straw, megasse or bagasse ; the sugar-cane refuse ; 
 and cotton-seed hulls, i.e., the residues of the cotton-oil and 
 cake industry retaining a proportion of cotton fibre (20 per 
 cent.) which has resisted the ginning process. Of this latter, 
 the amount available in the United States may be estimated 
 at 1,500,000 tons annually. 
 
 The separation and utilisation of this cotton hull fibre as a 
 staple papermaker's cellulose, has been very much advanced 
 by the recent invention of machines which effect a very perfect 
 separation of fibre from shell residues, producing a raw material 
 of 85 per cent. Cellulose concentration. An Anglo-American 
 Corporation (American Cotton Hull and Fibre Co.), exploiting 
 this invention, is already placing a considerable annual 
 tonnage on the European market. 
 
 For a general expose of this interesting development, we 
 refer to a paper by Beadle and Stevens, /. Soc. Chem. Ind. 28, 
 p. 1015. 
 
 As to megasse, which is certainly capable of producing a 
 staple half-stuff, fulfilling many of the requirements of the 
 papermaking industry, the potential supply, estimated on the 
 basis of the world's production of cane sugar, is 9,000,000 tons. 
 Many attempts have been made towards an effective industrial 
 solution of the problem, but so long as wood is able to meet 
 the world's demands, on the present basis of competitive 
 values, it imposes a standard of quality qud cellulose, or fibre, 
 
 D 
 
50 
 
 which competing raw materials have so far been unable to 
 meet. The reasons for this, which are technical and 
 economical, will be found fully dealt with in the standard text- 
 books. But, with increasing demand, and in absence of 
 general systematic forestry for maintaining the supply of raw 
 material, there may be a serious shifting of the economic 
 equilibrium, and a place made for one or more of the supplies 
 to be derived from present-day waste products. 
 
 But the wood cellulose industry cannot be said to have 
 reached its economic basis so long as we have to number the 
 by-products of the bisulphite process amongst the world's 
 wastes. The lignone constituents of the lignocellulose, or 
 wood substance, pass into solution in the cellulose process 
 with little change beyond that of sulphonation. Notwith- 
 standing this, and the high utility of the lignone complex in 
 the natural order, we, that is, industrial we, have no use for it. 
 This is one of the most conspicuous of our economic failures ; 
 the waste of organic matter in this form, potentially valuable, 
 is simply colossal. 
 
 It must not remain unmentioned that certain directions of 
 utilisation are being exploited, and technically developed ; but, 
 it must be confessed, on an insignificant scale. They only 
 serve to emphasise the fact of the general waste and loss of 
 value which eclipse the familiar and historical cases of glycerin 
 and the by-products of coal-gas manufacture. 
 
 Given a value of only ^"5 per ton for this material, obtain- 
 able in marketable form at little more than the cost of evapora- 
 tion, we see that in the wood cellulose industry there is still 
 one of those large margins of- unrealised value, which it is 
 difficult to credit in these days of advanced technology. 
 
 But the wood industry has yet another colossal waste to 
 bewail, and that is in the familiar form of sawdust, turnings 
 and general waste of mechanical processes. 
 
51 
 
 Here, again, we have certain directions of utilisation, e.g., 
 the mechanical grinding to wood meal and the chemical 
 processes of dry distillation, and fusion with alkalis for the 
 production of oxalic acid. Of minor uses, we may mention the 
 attempts to prepare fermentable sugars by processes of acid 
 hydrolysis, and employing these as the raw material for alcohol, 
 or the entire product as an ingredient of cattle foods. 
 
 But sawdust is still a typical " by-word," and if we could 
 knock the sawdust out of the world's dreams of wealth by 
 utilising it on an adequate scale, it could well afford to give up 
 dreams for a season. 
 
 There is, in conclusion, no conclusion to this subject, save 
 the formal one dictated by space and time limits ! As we said 
 at the outset, it is a subject for the younger generation of 
 chemists ; it is just beginning to take definite scientific shape, 
 and may be destined to carry us into regions of natural history 
 which our forefathers loved long since, and we, perhaps, have 
 lost awhile. 
 
52 
 
 EXHIBITS. 
 
 The lectures were illustrated by exhibits and a range of 
 special products, more particularly : 
 
 Artificial Silk (Viscose Process), full range of specimens, 
 for which we are indebted to Messrs. S. Courtauld & Co., Ltd. 
 
 Films of Cellulose (Viscose Process) one metre in width, 
 continuous length. These are manufactured by the Societe 
 Blanchisserie et Teinturerie de Thaon,and the Societe Fran9aise 
 de la Viscose, to whom we are indebted for the specimens. 
 
 Fee u lose, and its applications to coated art papers, 
 confectionery, etc., for which we are indebted to the Feculose 
 Co., of Paisley, N.B. 
 
 Tragasol, raw material, industrial forms, films, photo- 
 graphs, and specimens illustrating applications to leather, etc., 
 for which we are indebted to the Gum Tragasol Supply Co., 
 Ltd., of Hooton, Cheshire. 
 
 Cotton Hulls, raw material, bleached fibre, and specimens 
 of papers, for which we are indebted to the American Cotton 
 Hull and Fibre Company, Ltd., London. 
 
 Jackson Beater specimens of beaten materials, and 
 papers, for which we have to thank Mr. H. Jackson, of 
 Garstang, Lanes. 
 
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