All Whirling Through Space

A can-ful couip.irison cf the poêlttona of llie stars íroin one time to another -hows n maiiy cases a real motion in spuce. Rcally accurate asccrtainment of position began in the time of Bradley, who livt-d about the middleof the last century, so tliat we have only the records of a Hule over 100 years 011 wliicli to base our knowlediíe "f stellar "proper motion." European astrouomers gave us In tlie 1 :í s-r century several catalogue of stars which are icliable, and the work of comparUon with the present places has been undeitaken for a number of faint star?, the bright ones having already been ronsldered by an English orentleman, J. L. E Dreyer, who hM just publlshed the reaulU". By buch t-ftbrts as hls, continued overcentui ies of time, it will be possible flnally to deal intt-llifíently with the rreat probli-in of the motion of the universe as a whole. To apprcciate the feebiem-u of any cfforts if conlined toa sinjfle entury, it must be retnembered that the stars are so itnmensely remóte tliat but veiy fcvv of tbem sliow any perceptible gliil'ting of its place asa resul t o( the niotion of theearili in its orbit. Henee any motion. rapid though it mightbe, is searceiy perceptible bel. A change of a seeond of are h year, which niljjht be a perfectly amaing velncity, would require 1.S00 ye&n to carry the star over a space In the sky equnl to tlmt which the ful I moon covers. A second a year Is a lar;e proper moti-n. -