THE Imperial Institute is a centre for the exhibition and investigation of minerals with a view to their commercial development and for the suppIy of information respecting the sources, composition and value of minerals of all kinds. The Imperial Institute is provided with research Eabora tories for the investigation, analysis and assay of minerals, and undertakes reports on the composition and value of minerals, for the information of Governments and producing companies and firms, in communicatiol with the principal users in the United Kingdom and elsewhere in the Empire. Important minerals from within the Empire are exhibited in the respective Courts of the Public Exhibition Galleries, and also in the Mineral Reference Collections of the Institute. A special staff is engaged in the collection, critical revision and arrangement of aII import ant inf orrnation respecting sup plies of minerals especially within the Empire, new methods of usage and other commercial developments, Articles on these and related subjects are periodically pub lished in the Bulleti of the Im erial Iastitute, and monographs on special subjects are separately published under the direction of the Committee on Mineral Resources. Monographs are prepared either by members of the Scientific and Technical Staff of the Impend Institute, or by external contributors, to whom have been available the statistical and other special information relating to mineral resources collected and arranged at the Imperial Institute. The object of these Mo ographs is to give a general account of the occurrences and commercial utilisation of the more important minerals, particdarly in the British Empire. No attempt has been made to give details of mining or metal lurgical processes, HARCOURT, Chairman, Afinerui Resouycgs Cowm tee...