Harvard's Eclipse Expedition.

Within the past two or three years several expeditions have been sent from Harvard to various parts of the continent with the purpose of making a special study of one or more of the heavenly bodies. Of all these expeditions none have been more signally successful than the expedition sent to California in December of last year to make observations of the sun's eclipse which occurred on January 1. The party was under the charge of Professor William H. Pickering, and to him must be given much of the praise which is due the remarkable success attending the efforts of the party.

During the eclipse, especial observation was given to the corona and to the analysis of the spectrum, and the result has been that more striking and valuable photographs of those parts of the sun have been obtained than ever before. It seems almost probable that because of the important knowledge which must be gained by a close study of these photographs, the eclipse of 1889 will be looked upon, among men devoted to the study of practical astronomy, as marking an epoch in the history of solar physics. The great thirteen-inch Boyden telescope, with a lens specially corrected for photographic work, was successfully operated in securing eight large-scale pictures of the sun's corona, and these appear certain to be the finest representations of this strange object ever obtained. Up to this perion the great trouble has been that the representations of the sun's corona have been of so small a size as utterly to preclude the ability to study thoroughly the first filaments of its composition, and to resolve them with any degree of success into their elements. Therefore, scientific scholars will hail with enthusiasm the results which have been obtained at an expense of so much time and labor, and which will make it possible for them to pursue their researches intelligently and to have some solid foundation for many explanations which, up to this time, have been hardly more than conjectures.

It appears, from the observations, that the type of corona repeats itself in a period about the same as that of the solar spots, the corona of 1889 strongly resembling those of 1868 and 1878. The most important observations made at the eclipses of the dates just mentioned were obtained by the United States naval observatory. Its photographs and those of the Harvard expedition in January show an appearance of the corona to the east of the sun, much like that of a wedge, its sides extending far out in wavy lines; on the other side of the sun the coroan appears much brighter, and, from its cleft shape, bears a strong resemblance to the tail of a fish.

One important question which has been a mooted one in scientific circles for many years, will, no doubt, be conclusively settled on the development of the plates used by the Harvard expedition. It is the question whether or not any planet exists nearer the sun than Mercury. The opinions on this subject are divided. Each side has many strong arguments, but it has generally been conceded that, if judgment may be made from the movements of the other planetary bodies, this slight defection at times from their proper course would indicate the influence of an intra-Mercurial planet.