E. J. Bevan

“ The use of a rotary boiler is open to certain objections. In the first place, it is doubtful if they are as economical of soda as the vomiting boilers, especially the more recent patterns; and, secondly, the rotation of the boiler so disintegrates the pulp, that a certain proportion of the cellulose, especially those fibres which are short, is liable to be lost during the subsequent treatment. It seems probable that the best results would be obtained if the rotation of the boiler were reduced to a minimum, in fact, sufficient only to produce thorough circulation of the liquor. ”

“ On the other hand, every chemist knows that it is only the simpler of the carbohydrates which are so individualised as to be connoted by a particular formula in the stereoisomeric system. Leaving the monoses, there is even a doubt as to the constitution of cane sugar; and the elements of uncertainty thicken as we approach the question of the chemical structure of starch. This unique product of plant life has a literature of its own, and how little of this is fully known to what we may term the 'average chemist' is seen by the methods he will employ for its quantitative estimation. ”

“ The comparison of one paper with another with a view to ascertain the relative degree of sizing, is usually performed in a more or less rough and ready way by moistening the samples with the tongue for a certain time, and noticing the degree of transparency produced, which is of course inversely to the degree of hardness. 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 side. ”

“ A little reflection will prove that cellulose, starch, and sugar are of vast industrial moment in the order in which they are mentioned. If it is an open question to what extent science follows industry, or vice versa, it is not open to doubt that scientific men, and especially chemists, are called in these days to lead and follow where industrial evolution is most active. There is ample evidence of activity and great expansion in the cellulose industries, especially in those which involve the chemistry of the raw material ”

“ The determination of the strain or weight which a paper is capable of supporting is a very obvious measure of the strength of the paper. Observations of the limiting strain or breaking weight are sometimes made by paper-makers, but the apparatus and method employed are usually crude. The simplest means consist in clamping the paper—a strip of standard length and breadth, arbitrarily chosen—at one end, the clamp being firmly held in a fixed support, and to the other attaching by means of a similar clamp, an ordinary scale pan, the whole arrangement hanging vertically. ”

“ It is evident that raw materials make up a large fraction of the total cost; also that a very large item is the waste work of converting the cellulose into nitrate, only to remove the nitric groups so soon as the cellulose is obtained as thread.
It is clear that the aqueous solutions of cellulose have a double advantage in this respect—not only do they readily yield an approximately pure cellulose as a direct product of regeneration or decomposition, but the first cost of the solution is very much less. ”

“ One of the most characteristic of these modified celluloses constitutes the jute fibre, the isolated bast of an Indian plant, {17} which has an enormous industrial application for the coarser textile purposes. The chemistry of jute throws light on the course of lignification, the process by which cellulose is modified into wood, and in studying it in preference to wood we have the advantage of studying a simple tissue. ”

“ But as we are mainly concerned with the purely chemical factors we cannot pretend to deal with textile questions. We have to notice the remaining element of chemical economy as it involves a fundamental principle. The practice of washing residues or products of reaction free from reagents and soluble by-products involves a well-known mathematical law, under which the rate of purification is a function rather of the number of successive changes of washing liquid than of the volume of the latter. ”

“ A cheaper method, and one which is largely adopted in mills where only a coarse dark-coloured paper is required, consists in boiling the jute or other fibre in lime. Such a treatment is, however, not so effective as one in which caustic soda is used, and the fibre produced is harder and coarser in every way. The yield of pulp, however, owing to the fact that the fibre is imperfectly resolved, is greater. In many cases, from questions of economy, lime may be advantageously employed. ”

“ We have shown that the hydroxyfurfurals are constituents of the lignocelluloses. The proportion present in the free state is small, and it is not difficult to show that they are products of breakdown of the lignone groups. If we assume that such groups are derived ultimately from levulose, we have to account for the detachment of the methyl group. This, however, is not difficult, and we need only call to mind that the lignocelluloses are characterised by the presence of methoxy groups and a residue which is directly and easily hydrolysed to acetic acid. ”

“ Plant tissues, however, seldom, if ever, consist of pure cellulose, but contain besides, other products of growth either chemically combined with the cellulose or mechanically bound up with the tissue, which are, according to the nature of their union, removable either by means of fundamental chemical resolution or by the application of simple solvents. 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 cold, and subsequently boiling in dilute ammonia ”

“ A large amount of experimental matter has been accumulated in view of the ultimate contribution of the results to the general theory of colloidal solutions. But viscose is a complex product and essentially variable, through its pronounced tendency to progressive decomposition with reversion of the cellulose to its insoluble and uncombined condition. The solution for this reason does not lend itself to exact measurement of its physical constants such as might elucidate in some measure the progressive molecular aggregation of the cellulose in assuming spontaneously the solid (hydrate) form. ”

“ For the chemical identification of the fibres in a paper, the only available reactions are those with aniline sulphate solution. The majority of fibres (celluloses) give no reaction, straw and esparto celluloses and mechanical wood-pulp being the only ones that can be identified by its means. The authors have found that when a paper containing straw or esparto is treated for some time with a boiling 1 per cent. solution of aniline sulphate, a pink colour is produced. Esparto gives the reaction with greater intensity than straw. ”

“ Generally we may sum up the present solution of the problem of the relationship of the furfuroids to plant assimilation and growth as follows:—The pentoses are not produced as such in the process of assimilation; but furfural-yielding carbohydrates are produced directly and in approximately constant ratio to the total carbohydrates; they are mainly located in the permanent tissue; in the secondary changes of dehydration, &c., accompanying maturation they undergo such differentiation that they become readily separable by processes of acid hydrolysis from the more resistant normal celluloses ”

“ When a solution of gelatin is added to the liquors in which wood has been treated by any of the bisulphite or sulphurous acid processes, a body is precipitated in the form of a caoutchouc-like mass which can be dissolved in neutral sodium sulphite solution, or in weakly alkaline solutions, and can be reprecipitated on addition of alum to the solution. The substance consists of a compound of the gelatin with the non-cellulose constituents resembling, but not identical with, as has been supposed, the precipitate obtained by adding tannic acid to a solution of gelatin. ”

“ A group of constituents of many seeds, distinguished by giving slimy or ropy 'solutions' under the action of boiling water are designated 'amyloid.' They are reserve materials, and in this, as in the physical properties of their 'solutions,' they are very similar to starch. They are, however, not affected by diastase; and generally are more resistant to hydrolysis. Typical amyloids have been isolated by the author from seeds of Tropœolum majus, Pœonia officinalis, and Impatiens Balsamina. The raw material was carefully purified by exhaustive treatment with ether and alcohol, &c. ”

“ Whichever variety of “antichlor” is used an excess should be carefully avoided, as all act more or less upon the size and colouring matter added to the pulp subsequently. The proper method is to run in small quantities of a solution of the antichlor at a time, testing the pulps, after allowing a few minutes for complete admixture after each addition. The test is made by immersing a piece of iodide of potassium and starch paper, which will be turned blue so long as any calcium hypochlorite is present. ”

“ It is not a little remarkable that the main by-product of these bisulphite processes—the sulphonated derivatives of the lignone constituents of the wood—is still for the most part an absolute waste, notwithstanding the many investigations of technologists and attempts to convert it to industrial use (see [Pg 164] p. 149) . Seeing that it represents a percentage on the wood pulped equal to that of the cellulose obtained, it is a waste of potentially valuable material which can only be termed colossal. ”

“ The presence of starch in a paper can be readily ascertained by its behaviour with a solution of iodine. If starch be present the well-known blue colour of the compound of iodine and starch will be produced. The determination of the amount of starch present is a matter of some difficulty, the details of which are somewhat beyond the scope of the present work. It is based upon the conversion of the starch into sugar, and the estimation of the latter with Fehling’s solution. ”

“ As the group has been widened very much beyond these limits, it is clear that if any group term or designation is to be retained that of 'furfuroid' is 'neutral' in character, and equally applicable to saturated substances of such widely divergent chemical character as pentoses, hexosones, glycuronic acid, and perhaps, most important of all, levulose itself, all of which are susceptible of condensation to furfural or furfurane derivatives, as well as to those unsaturated compounds, constituents of plant tissues which are already furfurane derivatives. ”

“ For boiling and bleaching purposes it undoubtedly is, as when mixed with caustic soda or bleaching liquor they form a precipitate of carbonate of calcium, which lines the insides of boilers, breakers, and potchers as a hard scale, which is always liable to become detached, and to find its way into the finished paper. Moreover, carbonate of calcium is precipitated in the fibre, and carries with it a certain quantity of colouring matter, the subsequent removal of which is difficult. ”

“ This view receives some support from the fact that the interaction of the H2O2 with permanganates has now been established to be an oxidation of the H2 of the peroxide by the permanganate oxidation, with liberation, therefore, of the O2 of the peroxide as an unresolved molecule [Baeyer] .
Benzene itself is also powerfully attacked by the peroxide when shaken with a dilute solution in presence of iron salts. The products are phenol and pyrocatechol, with some quantity of an amorphous product probably formed by condensation of a quinone with the phenolic products of reaction. ”

“ This cement-like cupro-cellulose, as it may be termed, being insoluble in water, communicates water-resisting properties to the material so treated: moreover, the presence of copper renders the fabric less prone than before to be attacked by insects and mould, so that animal and vegetable life of a parasitic nature and fungoid growths are rarely, if ever, to be observed, even when the material is kept under conditions where boring worms, ants, rot, and mould, would be likely to attack it. ”

“ He also considers that the bisulphide of carbon, which must be regarded as a noxious compound, is a serious bar to the industrial use of the process, and for economic work he considers that the regeneration of ammonia from the precipitating liquors is necessary and would be as objectionable as the denitration baths in the collodion process. The final product not being on the market he does not pronounce a finally unfavourable opinion. ”

“ Esparto.—This fibre, on account of its high percentage of non-cellulose constituents, requires a large amount of soda to resolve it; on the other hand, being of the nature of a pecto-cellulose, the process of disintegration may be conducted at a low pressure; in fact, it is the practice at some mills to boil in open vessels, in which case, however, a larger amount of soda is required. As has been already stated, it may be taken as a general rule for all fibres, that within certain limits the higher the pressure employed the less soda is required. ”

“ It must be remembered that every special province of the science has its systematic beginning, and in that stage of evolution makes a temporary 'law unto itself.' In the absence of a dominating theory or generalisation which, when adopted, gives it an organic connection with the general advance of the science, there is no other course than to classify the subject-matter. Thus 'the carbohydrates' may be said to have been in the inchoate condition, qualified by a certain classification, prior to the pioneering investigations of Fischer. ”

“ It is obvious that while the spinner has to do with these filaments, the paper maker works up the ultimate fibre constituents or fibres. It is also an obvious corollary from this distinction that a fibrous material which from “weakness” is unavailable for textile application, may yet be perfectly “strong” from the paper maker’s point of view; in other words, the individual fibres may be strong, but have little cohesion in the filaments. ”