PREFACE. IT has been the intention of the Authors, in writing the present work, to prepare a complete Manual of Qualitative Chemical Analysis for the use of Laboratory Students, while it is hoped that more advanced experimenters also will find in it ample information concerning the rarer subjects of research. In attempting to accomplish this double purpose, care has been taken to avoid perplexing the beginner with the descriptions of the less common substances; with this intention, such descriptions are printed in small type. The present volume is not an account of general chemistry, nor does it contain descriptions of the apparatus employed, or of technical processes; for information on these points, reference must be made to special treatises*: but it aims to be a complete and systematic Guide to Qualitative Analysis, and to represent the present condition of this department of chemical science. To the following features of the present work the Authors would request the attention of Chemists, and of all those engaged in instructing pupils in Chemical Analysis: 1. In the First Part of the volume, at the end of each group * Mr. C. Greville Williams's admirable work will afford the student every information concerning apparatus and manipulation, while Dr. Odling's forthcoming Manual will convey, on all points connected with theoretical and descriptive chemistry, the most exact and trustworthy information, and also an able explanation of the grounds upon which the system of notation and equivalents adopted in the present work is based. of elements or salts, concise Tables are given, which show at a glance the most striking properties of the more common substances, as well as their most characteristic reactions. 2. The student is gradually accustomed to the use of chemical language, symbols, and formula, while, on the first mention of any new reaction, the equation representing it is clearly expressed, and the rationale of the process given. 3. In describing the salts and reactions of the various acid and basic radicals, the same order is invariably preserved. The monobasic salts come first, then the bibasic, and lastly the tribasic,— the basic elements commencing with those most decidedly positive. 4. If, in treating of any basic or acid-radical, a salt of characteristic properties is described, the corresponding salt of all basic or acid-radicals subsequently spoken of is invariably noticed. 5. The most characteristic compounds of each radical are printed in a conspicuous type. 6. Facilities are afforded for the progress of the student, in the simple analytical schemes appended to each group. 7. In the Second Part of the work, "The Method of Analysis" is described, ample directions and Tables being given,—while something is still left to the judgment of the pupil, who may frame tables for his own use from a study of the reactions, &c. detailed in Part I. 8. While the best methods of procedure in separations and testings are given, endeavour is made to impress on the student the necessity of an exact acquaintance with the nature of the processes concerned. By such means as those which they have just indicated, the Authors trust that they have attained to some degree of unity and simplicity, as well as of completeness, in the present treatise. The atomic weights employed in the present volume are those of Gerhardt, the atomic weights of Oxygen, Sulphur, Selenium, Tellurium, and Carbon being doubled, and the atomic weights of all the other elements remaining the same as those usually adopted. These alterations have long been made by Continental chemists; in England they have been strongly advocated by Professors Brodie and Williamson and Dr. Odling; and they have quite recently received the sanction of a large portion of the eminent British chemists. May the Authors hope that their work will be found to supply, in some degree, that want of a suitable handbook of analysis which must be caused by these changes? |