Manual Of The Chemical Analysis Of Rocks

PREFACE TO SECOND EDITION. SINCE the publication of the first edition of this book, Hille- brand s largely rewritten and amplified The Analysis of Sil- icate and Carbonate Rocks and a small manual by Dittrich have appeared. To the first of these I am indebted for sev- eral new methods, which I have used during the past few years, and which are introduced here, as well as some other methods and modifications in practice from other sources. These supersede or supplement those advocated before. Numerous changes have been made in the text, in part because of new matter or changes in procedure and also because more detail appeared to be needed. The important work of Mauzelius, confirmed by Hillebrand, on the influence of fine grinding, is discussed. The analysis of carbonate rocks, regarded as a special subject, has not been treated, as Hillebrands latest work covers this fully, and they are of minor importance to the petrologist. It may be permissible to remark that since 1904 the increase in the number and, still more, the improvement in the quality, of rock analyses have been very great, as will be brought out in a subsequent work. It is hoped that this little book has done its share, along with Hillebrands invaluable treatise, in aiding to place the science of petrology upon a firm chemical basis, the importance of which is well shown in the recent treatise on igneous rocks by Iddings. I have to record my obligations to Professor J. V. Lewis, for his kindness in undertaking to read the proofs duringmy absence. LOCUST, N. J., January, 1910. THE object of this book is to present to chemists, petrol- ogists, mining engineers and others who have not made a par- ticular study of quantitativeanalysis, a selection of methods for the chemical analysis of silicate rocks, and especially those of igneous origin. While the publication of such a work may seem superfluous in view of the existence of Hillebrands treatise on this special topic, yet justification may be found in the fact that the latter is intended, not so much for one who is not very conversant with the subject, as for the practised analyst, to whom it is an indispensable guide. A further reason for its appearance is that, apart from Hille- brands book and a paper by Dittrich, there does not seem to exist any separate modern treatise on the chemical analysis of rocks. The space devoted to this branch of analysis in the text- books is usually very small, and the various methods are widely scattered and often inadequately described. This is especially true in regard to the minutiae of manipulation and precautions to be observed, and to the determination of elements which, though usually accounted rare, have of late years been shown to be very common rock constituents. This neglect is rather striking in view of the prominence given in the last decade or so to the chemical composition of igneous rocks. There is an increasing number of geologists, petrologists, chemists and others, who are desirous of making chemical anal- yses of rocks, but who have had little or no experience in the subject, except that gained in the ordinary course of quantitative analysis, in which the study of silicates is usually confined to the examination of a feldspar or some such simple mineral. It is for the benefit of this class of students that the present book is written...