PREFACE: The preparation of this book was undertaken because it was felt that there was need of a work dealing primarily with the chemical aspects of the pulp and paper industry and embodying under one cover the results of recent investigations along this line. The endeavor has been to include all details which the chemist should have to enable him to grasp the methods of manufacture, but it is not intended to be a treatise on paper making in all its mechanical phases, and in fact the mechanical features of the industry are discussed only in so far as they are necessary for a satisfactory understanding of the chemistry involved. It has been written chiefly with the idea of helping the young technical man, whether chemist or chemical engineer, and it has therefore been assumed that the reader has a fair knowledge of the elements of chemistry. At the same time it has been attempted to write as simply and plainly as possible and it is believed that any one connected with the pulp and paper industry will find it helpful and suggestive. The subject matter has been collected from personal notes and experiences during the authors twenty years service as chemist in the industry, as well as from a careful review of the literature relating to the subject. The latter is often contra- dictory in the extreme and in certain cases it has proved almost impossible to reconcile conflicting statements. In such cases both sides of the argument have been presented as fairly as possible. It is peculiar to the industry that there are usually a large number of variable factors which influence any one operation, and since it is practically impossible to control all of these variables it necessarily follows that results in different mills will not be in harmony. For this reason it is expected that the observant reader will find statements to which he will take exceptions, but such differences of opinion are often desirable since they indicate lines of investigation which will lead to a better understanding of many things present obscure. which are at Regarding the methods of analysis and testing which are given it may be said that the attempt has been made to include all which are necessary for routine work in controlling opera- tions. There are many occasional analyses which it is necessary to make during special investigations, but it is impractical to include all of these and for such methods reference must be made to the numerous standard text-books of analytical procedure. L. Merrill Acknowledgment is made of the assistance of Mr. J. on the subject of Straw and also of that of my associates at the mills of S. D. Warren Company, whose encouragement has helped to overcome many difficulties. I am also indebted to the publishers ofVan Nostrands Chem- ical Annual for a number of the tables which will be found in the appendix. Contents include: CHAPTER I PAGE CELLULOSE Physiological and Physical. Composition and Constitution. Cellulose and Water. Solvents. Cellulose and Salts. Decomposition by Acids, Alkalis, Oxidants, Ferments and Heat. Compounds, Nitrates, Gun- Cotton, Nitrites, Acetates, Sulphuric Esters. Mixed Esters, Benzoates, Formates, Alkali-Cellulose. Sulpho-Carbonates. Groups of Celluloses. Compound Celluloses. Methods of Determination. CHAPTER II FIBROUS RAW MATERIALS t . . . 34 The Vegetable Cell. Seed Hairs. Bast Fibres. Fibres from Whole Stems. Woods. Length of Fibres. Densities and Composition of Woods. Bark and Knots. Decay. Woods used in Pulp Making. Bulk of Raw Materials. CHAPTER III RAGS, ESPARTO, STRAW, BAMBOO 68 Grades of Rags. Dusting. Boiling. Boilers. Losses. Esparto. Cleaning. Boilers. Cooking. Bleaching. Alkali Recovery. Straw. Com- position. Cooking with Lime. Soda Cooks. Bamboo. Sources. Analyses. Cooking...