the scientific estimate of the importance of cellulose as an in- dustrial product. The production of cellulose nitrate, the basis of modern military explosives, attained in 1918 to 5,000 tons per week in America alone. Another ester derivative of cellulose, the acetate, took a prominent and perhaps unique position in regard to war material, as the basis of the dope-dressing applied to the textile coverings of the wings of aeroplanes. The intensive production of these synthetic derivatives necessarily involved extensions of research with resulting additions to our knowledge of cellulose as a chemical individual, and in evidence of the magnitude of these industries and the wide scope of their tech- nology we may refer to E. C. Worden's elaborate treatise on the " Nitro Cellulose Industries." In evidence of the rapid growth of the subject in its wider aspects we may refer to the same author's treatise (projected in 1921), to be issued in ten volumes over a period of years.
Progress of investigation and knowledge of cellulose as a chemical individual was in 1921 more definitely marked as following three independent lines, obviously converging towards a constitutional formula or expression: (i) The study of cellulose as it is; a colloidal substance, perhaps the prototype of colloids, and of its immediately related derivatives, having closely similar physical properties. (2) The study of its resolutions by reaction to compounds of Ci-C 6 dimensions, also carbo-hydrates, which are presumed to be actual components, and, being compounds of known constitution, to be the foundation of an integral for- mula of constitution of the parent substance. With this primary or fundamental method is associated the study of the whole range of reactions and interactions of cellulose as diagnostic of its component groups. (3) The study of resolutions (a) to highly complex mixtures of products, by destructive distillation, or by natural processes of which the ultimate residual products are humus-lignite coal; (b) to ultimate products of C 3 -C dimensions by symbiotic bacterial process of decomposition.
Of the above, No. 2 is the line or method of systematic chem- istry, and its exponents detach themselves in the main from all considerations of the natural history and physiology of the celluloses: their organized structure and colloidal characteristics are treated as of subordinate moment, and the technology of the cellulose industries is for the most part ignored. Nevertheless, the contributions of this school of workers are of first importance.
The following are to be noted:
Resolution to Dextrose by ester formation, solution in water, and progressive hydrolysis of esters: (a) Reaction with H 2 SO4 Ost & Wilkening (1910-3) confirm Flechsig (1882) in the general con- clusion that cellulose is quantitatively converted to dextrose; (b) reaction with HC1. Aq. Willstatter and Zechmeister (1913). rediscovering the solvent action of the acid at maximum concentra- tion (W. A. Miller, Organic Chemistry, p. 130, ed. 1869), apply the reaction to an analogous process of resolution and further confirm the generally accepted relationship.
Resolution to Biose (cellobiose) and Monose (dextrose) following con- version into (a) acetic ester and (6) methyl and ethyl ethers or ethoxides (c) mixed (acetic) ester Aether derivatives. By the former, Ost has demonstrated the production of the biose as octacetate with the monose as pentacetate, the joint yield calculated to the monose representing 90% of the cellulose. By resolution of the methoxide derivatives Denham and Woodhouse obtain 1,2,5, trimethyl glucose and establish a critical constitutional point in regard to current discussion of the several alternative formulae based on the general acceptance of the quantitative cellulose dextrose relation- ship. The " acetolysis " of the ethoxides has been specially in- vestigated by Hess and Wittelsbach.
Resolution by Heat to Laevo-glucosan. A direction of research of critical importance is opened up by A. Pictet and co-workers, and subjecting cellulose (starch and glucose) to distillation in vacua (12.14 mra - at 210) with production of laevo-glucosan
CH-CHOH-CHz \o
in large yield (40 %). CHOH.CHOH.CH Helvetica Chem. Acta, 1918-20; also P. Karrer, ibid. 1920.
These notes are sufficient as evidence of the rapid advance of knowledge due to the active work and discussions of the chemists
whose ultima thule is expressed by a recent contributor " the time would now seem to be opportune when the question of direct synthesis should be undertaken." This project issues from a comprehensive critical discussion of the research work of the last decade (H. Hibbert, "The Constitution of Cellulose," Jour. Ind. Eng. Chem. 13 (1921), 256 et seq.), of which the following is characteristic " Cellulose is thus nothing more than a polymerised dextrose glucoside of dextrose."
As indicated above, the perspective of this school of workers is that of systematic chemistry, self-contained, and perhaps ar- bitrarily delimited from the objective relationships of cellulose as a dominant factor of the organic world and a main subject of natural history of which the complementary chapters are those of human industries.
Investigations from this point of view have also established points of critical importance:
1. The primary importance of specific volumes of cellulose and derivatives, for the adequate interpretation of reaction in this field.
2. The reactive continuity of cellulose: it reacts as a system, whereas systematic chemistry interprets its reactions in terms of a " molecular " individual.
_ 3. Cellulose is profoundly modified, structurally and constitu- tionally by mechanical shock and strain : as it is in degree propor- tionate to the active influence by all forms of energy (light, elec- trical current, heat).
4. Cellulose, is resolved by bacteria to ultimate products of C 3 -Ci dimensions: and recent research has brought these reactions under such control that the massive treatment of the " normal " celluloses is an industrial operation of the order of starch fermenta- tions. It is noteworthy that these transformations are in the main direct, and do not involve the transitional phases of the familiar operations of the brewer and distiller.
5. Lastly, as a negative point and a general criticism of the con- clusions of the school of systematic chemists, the cellulose-dextrose relationship postulating a conversion of 100 of cellulose to in dextrose is not established. Research in this field is limited to cotton cellulose. If extended to esparto cellulose (a type sharply and characteristically differentiated), to the wood celluloses, or even to cotton cellulose modified by mercerization and other treatments yielding products which maintain the structural characteristics, it would be recognized in the results that the " constitution of cellulose " is a problem of the dimensions of a continent rather than of a village: or possibly, that the " synthesis of cellulose " is an ideal, illusory, however useful. (The reader is referred to C. F. Cross, Canter Lectures " Cellulose " /. R. Soc. Arts 1920; and to papers by same author in /. Soc. Dyers and Col. 1918-20.)
Cellulose Products in War Service (1914-8). The following note on the development of the technology of the cellulose nitrates to meet the exacting requirements of the fighting services is contributed by Sir R. Robertson, who, as director of research at Woolwich, was responsible for the chemical technical control of the manufacture.
In England cellulose nitrates were. used during the war in the Land Service for the manufacture of cordite R.D.B., and for Admiralty cordite; towards the end of the war a small proportion was used for making nitro-cellulose powder. By far the largest use was for cordite R.D.B., as this propellant was ultimately manufactured at the rate of about 2,000 tons a week, involving the nitration of about 700 tons of purified cellulose. For Admi- ralty cordite over too tons a week of sliver cotton was prepared, this material being specially selected and purified. The cotton for the nitro-cellulose powders was a high grade of " linters."
The preparation of cellulose for the Land Service assumed the proportion of a great industry. The raw materials were drawn from wastes from the spinning-mills not only of England, but also of Egypt, India, and of other countries. It was soon found that the variations in treatment of the crude wastes produced a product which gave variable results after it had been nitrated, especially when it reached the stage of its incorporation with nitro-glycerine and gelatinization by means of ether-alcohol. All the materials for producing cellulose for nitration were there- fore coordinated under the Department of Explosives Supply, which instituted a system of chemical control of the product, with the objects of obtaining uniformity of production, reducing the quantity of impurities, and obtaining a suitable low viscosity. A uniform process of " kiering " (boiling under pressure with a lye of caustic soda) was introduced, and under strict supervision a
