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Retired Professor U. S. navy

“Hac sunt fastigia mundi"



Published October, 1901 Reprinted February, 1902; June, 1902; September, 1904.

Cbc knicherbocker press, Rcw pork

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WHEN the author accepted the flattering invita

tion of the editor to prepare a volume for the present “Science Series,” he supposed that it would be an easy task to sketch in simple language for the lay as well as the scientific reader the wonderful advances of our generation in the knowledge of the fixed stars. But, as the work went on, it became more evident at every step that such was not the case. The problem was, now to study whole chapters of observations and researches on some minute branch of the subject, and condense their gist into a few sentences; now to search volumes of periodicals, perhaps in vain, to find who was first in some field, or what result some investigator had reached; now to do justice to the respective works of students of the same subject; now to recast or rewrite passages in the light of some newly published research. The author must say in all candour that he has failed to surmount the difficulties thus arising in a way satisfactory to himself, and that in consequence the professional reader, if any such shall take up the book, will find defects that may seem to him serious in nearly every

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chapter. In palliation can be only pleaded the extent and complexity of the subject, and the impossibility of entering far into technical details in a work designed mainly for the general use. In treating such a subject it is impossible always to avoid the use of language more or less technical, except at the expense of precision and completeness of statement. An effort has however been made to limit the use of such language to the necessities of the case. The most gratifying experience associated with the work has been the cordial assistance and support rendered by a number of the author's friends and colleagues, who have supplied him with the material necessary to the presentation of their latest researches. Professor Campbell has supplied nearly all the material relating to spectroscopic binary systems, completed and revised the list of those objects, and freely placed at the author's disposal photographs taken at the Lick Observatory, including the frontispiece to the volume. Professor Kapteyn has supplied a large mass of material, published and unpublished, relating to his researches in stellar statistics, of which, however, only inadequate use could be made. Professor Pickering has permitted the free use of the treasures contained in the circulars and other publications of the Harvard Observatory, and Sir William Huggins has communicated the results of his latest studies in the life-history of the stars. Drs. A. A. Common and Isaac Roberts have each supplied a specimen of their photographs of nebulae, and Father Sidgreaves, S.J., of his photographs of spectra taken at the Stonyhurst College Observatory. Professor Barnard has allowed the use of his photographs of the Milky Way.

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