Part 1

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 re-writing of the second edition when it shall be demanded, in order to keep it abreast of the rapid progress in the field of agricultural chemical analysis.

WASHINGTON, D. C.,

Beginning of January, 1897.

TABLE OF CONTENTS OF VOLUME THIRD.

PART FIRST. SAMPLING, DRYING, INCINERATION AND EXTRACTIONS.

Introduction, pp. 1-3.—Methods of study; Scope of the work; Limitations of work; General manipulations.

Methods of Sampling, pp. 3-13.—Vegetable substances; Animal substances; Preserving samples; Collecting samples; Grinding samples; Grinding apparatus.

Drying Organic Bodies, pp. 13-36.—Volatile bodies; Drying ovens; Air baths; Drying in vacuum; Electric drying ovens; Steam coil apparatus; Drying in hydrogen; Drying in tubes; Drying viscous liquids; General principles of drying.

Incineration, pp. 36-40.—Principles of incineration; Products of combustion; Purpose and conduct of incineration; German ash method; Courtonne’s muffle.

Extraction of Organic Bodies, pp. 40-57.—Object of extraction; Solvents; Methods of extraction; Extraction by digestion; Extraction by percolation; Apparatus for extraction; Knorr’s extraction apparatus; Soxhlet’s extraction apparatus; Compact extraction apparatus; Recovery of solvents; Authorities cited in Part First.

PART SECOND. SUGARS AND STARCHES.

Introduction, pp. 58-62.—Carbohydrates; Nomenclature; Preparation of pure sugar; Classification of methods of analysis.

Analysis by Density of Solution, pp. 63-72.—Principles of the method; Pyknometers; Calculating volume of pyknometers; Hydrostatic balance; Areometric method; Correction for temperature; Brix hydrometer; Comparison of brix and baumé degrees; Errors due to impurities.

Estimation of Sugars with Polarized Light, pp. 74-120.—Optical properties of sugars; Polarized light; Nicol prism; Polariscope; Kinds of polariscopes; Character of light; Description of polarizing instruments: Laurent polariscope; Polariscope lamps; Soleil-Ventzke polariscope; Half Shadow polariscope; Triple field polariscope; Setting the polariscope; Control observation tube; Quartz plates; Correcting quartz plates; Application of quartz plates; Sugar flasks; Preparing sugar solutions for polarization; Alumina cream; Errors due to lead solutions; Double polarization; Mercuric compounds; Bone-black; Inversion of sugar; Clerget’s method; Influence of strength of solution; Calculation of results; Method of Lindet; Use of invertase; Activity of invertase; Inversion by yeast; Determination of sucrose; Determination of raffinose; Specific rotatory power; Calculating specific rotatory power; Variations in specific rotatory power; Gyrodynatic data; Birotation.

Chemical Methods of Estimating Sugar, pp. 120-149.—General principles; Classification of methods; Reduction of mercuric salts; Sachsse’s solution; Volumetric copper methods; Action of copper solution on dextrose; Fehling’s solution; List of copper solutions; Volumetric laboratory method; Filtering tubes; Correction of errors; Permanganate process; Modified permanganate method; Specific gravity of cuprous oxid; Soldaini’s process; Relation of reducing sugar to quantity of suboxid; Factors for different sugars; Pavy’s process; Peska’s process; Method of Allein and Gaud; Method of Gerrard; Sidersky’s modification; Titration of excess of copper.

Gravimetric Copper Methods, pp. 149-170.—General principles; Laboratory copper method; Halle method; Allihn’s method; Meissl’s method; Determination of invert sugar; Estimation of milk sugar; Determination of maltose; Preparation of levulose; Estimation of levulose.

Miscellaneous Methods of Sugar Analysis, pp. 171-196; Phenylhydrazin; Molecular weights of carbohydrates; Birotation; Estimation of pentosans; Determination of furfurol; Method of Tollens; Method of Stone; Method of Chalmot; Method of Krug; Precipitation with pyrogalol; Precipitation with phloroglucin; Fermentation methods; Estimating alcohol; Estimating carbon dioxid; Precipitation with earthy bases; Barium saccharate; Strontium saccharate; Calcium saccharate; Qualitive tests; Optical tests; Cobaltous nitrate test; The Dextrose group; Tests for levulose; Tests for galactose; Tests for invert sugar; Compounds with phenylhydrazin; Detection of sugars by means of furfurol; Bacterial action on sugars.