We are indebted to the standard works of Allen, Crookes, Fresenius, Lunge, Michell, Percy, and Sutton, and wish to express our sense of special indebtedness to Mr. Richard Smith, of the Royal School of Mines. One or two of the illustrations are taken from Mr. Sexton's excellent little book on _Qualitative Analysis_. Our obligation to some others is mentioned in the text. Finally, we have to thank for assistance in the experimental work Messrs. Bailey, Beswick, Clarke, Grant, Higgins, and Smith. THE AUTHORS. CAMBORNE, _Nov. 1889_. CONTENTS. PART I. CHAPTER I. INTRODUCTORY. Page Object of assaying 1 Sampling 1 Drying: determination of moisture 5 Calculation and statement of results 7 Laboratory books and report forms 9 Quantity to be taken for an assay 11 Exercises 14 CHAPTER II. METHODS OF ASSAYING.--DRY GRAVIMETRIC METHODS. Methods of assaying 15 Gravimetric methods 15 Mechanical separations 16 Dry assays 16 (a) Fluxes 16 (b) Reducing agents 21 (c) Oxidising agents 22 (c) Apparatus 24 CHAPTER III. WET GRAVIMETRIC METHODS. Wet gravimetric methods 27 (a) Solution 29 (b) Precipitation 30 (c) Filtration 31 (c) Drying and igniting 32 CHAPTER IV. VOLUMETRIC ASSAYS. Titrometric assays 35 (a) Standard solutions 36 (b) Standardising 37 (c) Methods of working 42 (c) Indirect titration 43 Colorimetric assays 44 Gasometric assays 44 CHAPTER V. WEIGHING AND MEASURING. Weighing 47 Measuring liquids 49 (a) Graduated flasks 49 (b) Pipettes 50 (c) Burettes 51 Measuring gases 52 CHAPTER VI. REAGENTS. Acids, &c. 54 Bases, salts, &c. 59 CHAPTER VII.