Page:Popular Science Monthly Volume 69.djvu/182

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POPULAR SCIENCE MONTHLY

tory. Madame Ceraski has been especially successful in finding variables of the interesting Algol type. Of sixty-seven variable stars discovered by her, no less than ten are of this class. This is remarkable when we take into consideration that of over 3,000 variables now known only thirty-eight are of the Algol type.

Through her generous gifts in aid of astronomical research, the late Miss Catherine W. Bruce, of New York, made her name widely known in astronomical circles. Dr. Max Wolf, director of the Astrophysical Observatory at Heidelberg, was presented by her with a photographic telescope, which has enabled him not only to find some seventy new asteroids, but also to increase materially the number of known

The Small Magellanic Cloud in which nearly a Thousand Variable Stars have been found. To the right is the globular cluster, 47 Tueanæ, taken at Arequipa in the bruce telescope.

variables. Dr. Wolf, recently assisted by Frau G. Wolf, has discovered about 200 new variable stars.

Nowhere else, however, has so large a collection of celestial photographs been made, covering so long a period of time, as at the Harvard Observatory. In 1903, Professor Pickering instituted, among other pieces of work, an examination of the Magellanic Clouds. This work was assigned to Miss H. S. Leavitt, who has shown rare talent for this line of investigation. The regions selected were very fortunate, also, since, aside from the dense globular clusters, no other region has been found as rich in variables as the Small Cloud, although the Large Cloud also promises to yield nearly as many. It should be noted that the Magellanic Clouds are by no means merely irregular extensions of the Milky Way. They appear to be as unique in structure as in position.