MOTIONS OF THE STARS. 541 



and needles have been magnetized just as if a battery had been em- 

 ployed. 



There are many other points of similarity which might be enlarged 

 upon ; but, if one were to attempt to set down all the strange and vari- 

 ous considerations which come under cognizance in this subject, they 

 would soon swell the matter much beyond the limits of a magazine 

 article. Fraser's Magazine. 



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MOTIONS OF THE STAES. 



AT the last meeting of the Royal Astronomical Society, Dr. Hug- 

 gins, the eminent spectroscopist, made an extraordinary state- 

 ment respecting the motions taking place among the stars. The re- 

 sults be announces are so wonderful that it will be well briefly to explain 

 how they have been obtained, as well as their relation to what had 

 formerly been known upon the subject. 



Our readers are doubtless aware that the stars are not really fixed, 

 but are known to be travelling swiftly through space. To ordinary 

 observation the stars seem unmoving ; nor indeed can the astronomer 

 recognize any signs of motion save by prolonged observation. But, if 

 the exact place of a star be carefully determined at any time, and again 

 many years later, a measurable displacement can be recognized ; year 

 after year, and century after century, the motion thus determined pro- 

 ceeds, until at length the star may be removed by a considerable arc 

 (or what is so regarded by astronomers accustomed to deal with the 

 minutest displacements) from the position it had formerly occupied. 



But, in general, these movements afford no means of estimating the 

 real rate at which the stars are travelling through space. In the first 

 place, a star might be moving with enormous rapidity toward or from 

 the earth, and yet seem to be quite fixed on the star-vault just as the 

 light of a rapidly approaching or receding train seems to occupy an un- 

 changing position if the train's course is at the moment in the direction 

 of the line of sight. It is only what may be called the thwart-motion 

 of the star that the astronomer can recognize by noting stellar dis- 

 placements. But even this motion he cannot estimate in miles per 

 second, say unless he knows how far off the sun is; and astronomers 

 know in truth very little about stellar distances. 



Now, it seems, at first sight, altogether hopeless to attempt to 

 measure the rate at which a star is approaching or receding. No 

 change of brightness could be looked for, nor indeed could any ob- 

 served change be trusted as an evidence of changed distance, since 

 stars are liable to real changes of brilliancy, much as our own sun 

 is liable to be more or less spot-marked. But the distances of the 



