Please see the Transcriber’s Notes at the end of this text.
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THE RARE EARTHS
THE RARE EARTHS
THEIR OCCURRENCE, CHEMISTRY,AND TECHNOLOGY
BY
S. I. LEVY
B.A. (Cantab.), B.Sc. (Lond.), A.I.C.
LATE HUTCHINSON RESEARCH STUDENT OF ST. JOHN'S COLLEGE
CAMBRIDGE
WITH ILLUSTRATIONS
LONDON
EDWARD ARNOLD
1915
[All rights reserved]
[v]
PREFACE
During the thirty years which have elapsed since Dr. Auer’sapplication of the rare earths to the production of artificiallight, the incandescent mantle industry has developed to anextent which gives it a prominent place among those chemicalindustries which may be considered essential to modern civilisation.This technical development has in turn assisted andstimulated the scientific examination of the elements of thisgroup, with the result that ordered and accurate knowledgeis beginning to replace the confused and uncertain datawhich had been collected by earlier workers in the field. Theseadvances have served to emphasise the scientific interest andimportance of the rare earth group, and the difficulty of bringingit into relation with the other elements. The relatively scantattention devoted to the study of this province of inorganicchemistry by teachers and students in England is probablydue no less to the difficulty in classification, and the uncertaintywith regard to the homogeneity and individuality of the variousmembers of the family—an uncertainty by no means entirelyremoved even now—than to the fact that the very extensiveliterature on the subject is somewhat confused and difficultof access, especially to those unfamiliar with the French andGerman languages.
The present work is intended to give a general but fairlycomprehensive account of the rare earth group. In accordancewith general usage, the elements zirconium and thorium havebeen included, though these are now recognised as falling outsidethe limits of the rare earth group proper. The inclusion oftitanium, which chemically is so far removed from the ceriumand yttrium elements, has been considered desirable, not onlyon account of its general occurrence in the rare earth minerals,and its position in Group IVB with zirconium, cerium, andthorium, but also on account of its increasing chemical and[vi]technical interest, and its use in the ordinary quantitativelaboratory operations.
Though the nature of the matter embraced has renderedthe division into three parts desirable, the whole subject hasbeen treated primarily from the chemical standpoint. Inview, however, of the occurrence of considerable quantitiesof monazite within the British Empire, and of the possibilitythat in the near future the Brazilian fields will n