WOOD PRODUCTS DISTILLATES AND EXTRACTS PART I. THE CHEMICAL PRODUCTS OF WOOD DISTILLATION PART 11. DYEING AND TANNING EXTRACTS FROM WOOD - PREFACE TO THE FRENCH EDITION WHILST - perusing the sheets of the technical treatise which MM. P. Dumesny and J. Noyer have asked me to present to the public, I could not help being struck with the progress which chemical science has accomplished in the last thirty years-a progress which leads it, step by step, to explore all parts of the field of human activity, and to biing to each of those parts the measure of knowledge which it requires. At first the preoccupation of men of science was necessarily dominated by theoretical ideas, by verification of hypotheses, and by the building up of a system of doctrines capable of simultaneously satisfying not only the desire which we possess of demonstrating more and more intimately the constitution of matter, but also the need for simplification of the methods of teaching, and for the incessant realisation of fi-esh progress. But realism never loses its rights. It was soon perceived that chemistry could not remain confined to the domain of the laboratory, that the problems of life were within its field, and that its scope became enlarged by association with the material works of mankind, by lessening human labour, and, consequently, increasing the riches and the happiness of different nations. Thus it is that we see men of science interest themselves to an ever-increasing extent in a, oricultural and industrial problems, and the teaching of industrial chemistry develop in all large countries, and so produce engineers capable of not only placing theory and practice in harmony in each industry, but capable also of modifying, of inventing and of sustaining the competition of products by diminishing their cost price. It is with the same end in view that, alongside purely scientific literature, a need has made itself felt for technical literature, to enlighten not only the young in their arduous search after knowledge, and not only the manufacturers themselves, but also their assistants, workmen and foremen whose professional skill is by this acquired knowledge relatively increased. And here again a natural departure was made. It was to those industries which, working on a large scale and handling considerable capital, were-and should have been-able to be the first to make an appeal to the assistance of the man of science that attention was first of all directed. It is now the turn of industries which, occupying a secondary rank, are, nevertheless, of great importance, as much by the riches which they create as the necessity for the products which they place on the market, and Wood Products, Distillates and Extracts aEe of this latter category. In France, a wooded country, the industrial chemistry of wood employs a great number of hands. The living which is made out of it is a somewhat hard one, since the charcoal which it prepares has to compete, especially on the markets of large towns, with many rivals, as a source of heat and particularly with gas...