instruction to large classes in the laboratory. It is the authors' practice to examine their classes orally every four or five exercises, in order to secure close attention to the reasoning of the subject. With this exception, the subject is studied exclusively in the laboratory, tools in hand. Fifty laboratory exercises of two hours each have proved sufficient to give their classes a mastery of the subject as it is presented in this manual. It is scarcely necessary to say that this little work is a compilation from well-known authorities, among which may be particularly mentioned the works of Galloway, Will, Fresenius, and Northcote & Church. BOSTON, April, 1869. PREFACE TO THE REVISED EDITION. In this revised edition, undertaken with the advice and consent of the authors, such alterations and additions have been made as have been suggested by the use of the book with a number of classes in the laboratory. BOSTON, July, 1876, W. R. N. ercises, subject. e labor- rs each subject ompila- cularly TABLE OF CONTENTS. Introduction. Qualitative analysis defined. Scope of this manual. PART I. Chapter I. Example of the separation of two elements. Division of Chapter II. Class I. Chlorides insoluble in water and acids. Lead. The pre- Chapter III. Class II. Sulphides insoluble in water, dilute acids and Chapter V. Class IV. Hydrates insoluble in water, ammonia-water, Chapter VI. Class V. Sulphides insoluble in water and in saline or Chapter X. Special tests for the non-metallic elements. Effervescence. Carbonates. Cyanides. Sulphides. Sulphites. Hyposulphites. Chro- mates. Arsenites and Arseniates. Sulphates. Phosphates. Oxalates. Tartrates. Borates. Silicates. Fluorides. Chlorides. Bromides. Chapter XI. Treatment of a salt, mineral or other non-metallic solid. Preliminary examination in the dry way. Closed-tube test. Gases or vapors to be recognized. Sublimates. Re- ... aqueous solution: neutral, acid, alkaline. An acid solution. • • • of carbonate of calcium and chloride of ammonium. Fusion with acid sulphate of sodium. Deflagration. Chapter XII. Treatment of a pure metal or alloy. Action of nitric 121-12 Reagents. Acids. Sulphuretted hydrogen. Ammonia-water. Ammo- paper. Starch Solutions of known composition. Utensils. Reagent-bottles. Test-tubes. Test-tube rack. Flasks. Beakers. Glass funnels. Filtering. Filter-stand. Rapid filtration. Porcelain dishes and crucibles. Lamps. Blast-lamps and blowers. Iron-stand. Tripod. Wire-gauze. Triangle. Water-bath. Sand-bath. Blowpipes. Platinum foil and wire. Pincers. Platinum crucibles. Wash-bottle. Glass tubing. Stirring-rods. Cutting and cracking glass. Bending and closing glass tubes. Blowing bulbs. Caoutchouc. Corks. Gas-bottle. Self-regulating generator. Mortars. B QUALITATIVE ANALYS INTRODUCTION. 1. Qualitative Analysis, in the widest sen is the art of finding out the elements containe substances. The general definition has import in practice. In the first place, the art, as con applies almost exclusively to mineral, or inorgan and touches only incidentally upon the multifari of carbon with hydrogen, oxygen, nitrogen a elements, which form the subject-matter of t chemical science called organic chemistry. analysis of gases constitutes a distinct bran requiring methods and apparatus of its own to be most advantageously studied by itself. tions made, there remains the analysis of in and liquids, which is in fact the main subject analysis in the present technical sense of the t Of the sixty-three recognized chemical elen thirty-four most important are embraced in course of this manual. Means of detecting a common elements are incidentally given; bu elements which are so rare as to be at present est except to the professional chemist or mine alluded to. 2. Some previous knowledge of general sential to the successful study of qualitative a assumed that the student knows something elements and of their most important combinations, that he is familiar with the principal laws which govern chemical changes, and that he possesses a certain skill in the simplest manipulations. The tools and operations employed in qualitative analysis are few and simple; but neatness, method in working and a vigilant attention even to the minutest details, are absolutely essential. As the various substances used or produced in the operations of analysis will not be particularly described, the careful student will keep at hand some textbook on general chemistry, to which he can constantly refer to refresh his recollection of the formulæ and physical and chemical properties of the substances referred to. It should be observed that it is often very difficult — in fact, impossible in the present state of knowledge to express in exact equations the involved or obscure reactions which occur in complex mixtures during the operations of analysis. It is a useful exercise for students to write out in equations the simpler chemical changes which occur in analysis; but when the attempt is made to put a complex reaction into numerical symbols, the equations are apt to express either more than we know, or less. 3. Although the detection of the elements contained in compound substances is the ultimate object of analysis, it is only by exception that the elements themselves are isolated, and recognized in their uncombined condition. An element is generally recognized through some familiar compound, whose apparition proves the presence of all the elements it contains, just as the presence of any word upon this page makes it sure that the letters with which it is spelt are imprinted there. If, as the result of a definite series of operations upon some unknown body, the hydrated oxide of iron be produced, no iron having been added during any stage of the process, the proof of the presence of iron in the original body is quite as certain as if the gray metal itself had been extracted from it. If some well-known sulphate, like sulphate of lead, or of barium, for example, result from a series |