STATIONARY METEOR RADIANTS.—Since Mr. Denning announced the existence of stationary meteoric radiants in 1878, many observers have endeavoured to explain, and account for, them, hitherto without much success. The apparent radiant of a meteor depends almost as much on the true direction of the earth's motion as it does on the true motion of the meteor itself, therefore it seems almost impossible that these bodies should appear to stream from the same point of the heavens for months at a time. In an article appearing in No. 5, vol. xxix., of the Astro-physical Journal (June, p. 365), Prof. W. H. Pickering shows, however, that this apparently puzzling phenomenon is only what is to be expected, arguing from our present knowledge of meteor-orbits. Briefly, He shows by diagrams and tables that the attracting force of the earth's mass is, at different times, capable of deflecting or accelerating the smaller bodies, so that the apparent change of the longitude of the radiant counterbalances the variation produced by the earth's motion; thus the radiant appears to be stationary, or nearly so. Prof. Pickering also produces arguments against the prevalent idea that meteors are generally of infinitesimal mass.