The Præsepe Cluster¹

Abstract

THIS work belongs to a class of investigations whose number has been steadily increasing in the last few years. The discussion of the relative motion of stars in loosely aggregated groups is a study that may throw light on intricate questions connected with the structure of the cosmos; and in this point of view, the Pleiades group has been discussed by several astronomers since Bessel laid the foundation for such inquiries more than fifty years since. The cluster in Perseus, the stars about the nebula of Orion and some other groups have already engaged the attention of astronomers, but nothing more complete or more interesting has appeared than the present investigation due to Dr. Schur; and it will hold its own till lapse of time gives a more trustworthy hold upon the small mutual displacements which successive investigations may reveal, for greater accuracy of measurement can scarcely be expected.