Transcriber’s Notes: Underscores “_” before and after a word or phrase indicate _italics_ in the original text. Equal signs “=” before and after a word or phrase indicate =bold= in the original text. A single underscore after a symbol indicates a subscript. Small capitals have been converted to SOLID capitals. Illustrations have been moved so they do not break up paragraphs. Antiquated spellings have been preserved. Typographical and punctuation errors have been silently corrected. The “CORRECTIONS FOR VOL. III.” listed at the end of the book have already been applied to the text by the transcriber. PRINCIPLES AND PRACTICE OF AGRICULTURAL ANALYSIS. A MANUAL FOR THE EXAMINATION OF SOILS, FERTILIZERS, AND AGRICULTURAL PRODUCTS. FOR THE USE OF ANALYSTS, TEACHERS, AND STUDENTS OF AGRICULTURAL CHEMISTRY. VOLUME III. AGRICULTURAL PRODUCTS. BY HARVEY W. WILEY, CHEMIST OF THE U. S. DEPARTMENT OF AGRICULTURE. EASTON, PA. CHEMICAL PUBLISHING CO. 1897. COPYRIGHT, 1897, BY HARVEY W. WILEY. PREFACE TO VOLUME THIRD. The concluding volume of the Principles and Practice of Agricultural Analysis has been written in harmony with the plan adopted at the commencement of the first volume. In it an effort has been made to place the analyst or student _en rapport_ with all the best methods of studying the composition of agricultural products. During the progress of the work the author has frequently been asked why some special method in each case has not been designated as the proper one to be used. To do this would be a radical departure from the fundamental idea of the work; _viz._, to rely on the good judgment and experience of the chemist. It is not likely that the author’s judgment in such matters is better than that of the analyst using the book, and, except for beginning students pursuing a course of laboratory instruction, a biased judgment is little better than none at all. For student’s work in the laboratory or classroom it is probable that a volume of selected methods based on the present work may be prepared later on, but this possible future need has not been allowed to change the purpose of the author as expressed in the preface of the second volume “to present to the busy worker a broad view of a great subject.” For the courtesy and patience of the publishers, for the uniformly commendatory notices of the reviewers of volumes one and two, and for the personal encouraging expressions of his professional brethren the author is sincerely grateful. He finds in this cordial reception of his book a grateful compensation for long years of labor. The plates of the first edition of the three volumes have been destroyed in order to insure a