PRINCIPLES AND PRACTICE —OF— AGRICULTURAL ANALYSIS. A MANUAL FOR THE ESTIMATION OF SOILS, FERTILIZERS, AND AGRICULTURAL PRODUCTS. FOR THE USE OF ANALYSTS, TEACHERS, AND STUDENTS OF AGRICULTURAL CHEMISTRY. VOLUME I. =SOILS.= BY HARVEY W. WILEY, CHEMIST OF THE U. S. DEPARTMENT OF AGRICULTURE. EASTON, PA., CHEMICAL PUBLISHING CO., 1894. COPYRIGHT, 1895, BY HARVEY W. WILEY. PREFACE TO VOLUME FIRST. In this volume I have endeavored to place in the hands of teachers and students of Agricultural Analysis, and of analysts generally, the principles which underlie the science and art of the analysis of soils and the best approved methods of conducting it. In the prosecution of the work I have drawn freely on the results of experience in all countries, but especially in the matter of the physical examinations of soils, of this country. Science is not delimited by geographic lines, but an author is not to be blamed in first considering favorably the work of the country in which he lives. It is only when he can see nothing of good outside of its own boundaries that he should be judged culpable. It has been my wish to give full credit to those from whose work the subject-matter of this volume has been largely taken. If, in any case, there has been neglect in this matter, it has not been due to any desire on my part to bear the honors which rightfully belong to another. With no wish to discriminate, where so many favors have been extended, especial acknowledgments should be made to Messrs. Hilgard, Osborne, Whitney, and Merrill, for assistance in reading the manuscript of chapters relating to the origin of soils, their physical properties, and mechanical analysis. With the wish that this volume may prove of benefit to the workers for whom it was written I offer it for their consideration. H. W. WILEY. WASHINGTON, D. C., Beginning of January, 1895. TABLE OF CONTENTS OF VOLUME FIRST. PART FIRST. _Introduction_, pp. 1–27.—Definitions; Origin of soil; Chemical elements in the soil; Atomic masses; Properties of the elements; Relative abundance of the elements; Minerals occurring in rocks; Classification of minerals. _Rocks and Rock Decay_, pp. 28–43.—Types of rocks; Microscopical Structure of Rocks; Composition of rocks; Color of rocks; Kinds of rocks; Eruptive rocks.