PREFACE.

THE object of this work is the same as that of other volumes of the International Scientific Series, to which it belongs-viz. to place before the general reader a short but clear picture of the modern aspects of the science of which it treats.

With this view, the more elementary parts of the subject-weather science-have been treated of in the first three chapters of the book, while the more difficult questions are reserved for the later portion of the work. Though this method of treatment involves a certain amount of repetition, the author hopes that the wo.k may thus prove acceptable to a large number of readers who would have been deterred from the perusal of a more formal treatise.

This book is not intended to be in any way an encyclopædia of meteorology, or a mere repertory of facts. Our endeavour has been to sketch the great principles of the science as a whole, and to give a clear

picture of the general conclusions as to the actual nature of weather to which meteorologists have been led.

Many books have been written on storms and climate, but none on everyday weather. The whole of this work is devoted to weather, in the tropics as well as in the temperate zone.

This volume is not a mere compilation of existing knowledge, for the results of many of the author's original and unpublished researches are included in its pages. Such, for instance, as the explanation of many popular prognostics; the elucidation of the general principles of reading the import of cloud-forms; the classification of those cases in which the motion of the barometer fails to foretell correctly the coming weather; and the character of that kind of rainfall which is not indicated in any way by isobaric maps.

Most of the charts are derived from the publications of various meteorological offices; but almost all the diagrams have been drawn for this work, or have only appeared in some of the author's papers.

Every endeavour has been made to do justice to the discoverers of any new principle, but it has not been considered necessary to give references to all the original authorities in a popular work.

To those who have only known meteorology as a dull branch of statistics, the perusal of these pages may perhaps open a new prospect in science, and a new vision to the mind.

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The author wishes specially to acknowledge the assistance which he has received from the Meteorological Office in London, and the United States Signal Office, by the supply of the material contained in some of their various publications; and also the courtesy of the Council of the Royal Meteorological Society of London, in lending him the blocks which have illustrated several of his own papers.

His thanks are also due to Mr. R. Ellery, of Melbourne Observatory, and Mr. W. E. Cooke, of Adelaide Observatory, for information and diagrams to illustrate Australian weather and forecasts; and to Mr. H. F. Blanford, meteorological reporter for the Government of India, for information and material relating to the nature of the

monsoons.