Page:Popular Science Monthly Volume 10.djvu/89

Rh has partaken of the general character of official astronomical research, we may consider here some of the special astronomical occasions at which the observers trained at Washington have assisted.

The total eclipse of August 7, 1869, was closely observed by parties from the observatory. Prof. Asaph Hall and Mr. J. A. Rogers proceeded to Alaska; Profs. Newcomb, Harkness, and Eastman, to Iowa; and Mr. F. W. Bardwell, to Tennessee. The observations made on this occasion were of great value and interest. The solar prominences had had their real nature determined during the eclipse of August, 1868; and the American observers were not content to repeat the observations then made, but extended the method of spectroscopic analysis to the corona. They also obtained photographs of the colored prominences. The work accomplished by the Washington observers, together with the observations made by Dr. Curtis, Mr. J. Homer Lane, of Washington City, Ind., and Mr. W. S. Gilman, Jr., of New York, and General Myer, U. S. A., form a quarto volume of 217 pages, with twelve illustrations. Of this valuable and interesting volume, 3,500 copies were printed by joint resolution of Congress.

The superintendent of the Washington Observatory was not content with this. "Believing that the experience of its officers in their observations of the eclipse of 1869 should be availed of for the further elucidation of the subjects involved in such phenomena, he addressed the Navy Department upon the subject of their employment in Europe in observing the eclipse of December, 1870; the department promptly detailed the professors who had been the observers of the previous year;" and it was doubtless through the energy thus displayed by Rear-Admiral Sands that other skillful American astronomers were enabled to cross the Atlantic for the purpose of observing that important eclipse. Unfavorable weather prevented observations of this eclipse at some of the best stations, but the American observers succeeded in establishing the accuracy of the observations made in 1869, and to them must be attributed in large part the definite demonstration of the fact, which though now admitted was then much disputed, that the corona is a solar phenomenon, and not due to the illumination of our own atmosphere only.

The part taken by the Washington Observatory in preparing for and coöperating in the observation of the transit of Venus, on December 8, 1874, is too recent to need full description in this place. I may be permitted, however, to dwell with special commendation on the manner in which American astronomers devoted themselves at that time to a task which they might fairly have thought the business of their European brethren. A transit of Venus is to occur in 1882 which will be specially American, being visible wholly or in part from every portion of the United States; and, if America had reserved her energies for that occasion, no complaint could reasonably have been