PROGRESS OF MODERN ASTRONOMY 



the great Russian observatory, which so long held the 

 palm over all others, had now been established; and 

 Thomas Henderson, then working at the Cape of Good 

 Hope, but afterwards the Astronomer Royal of Scot- 

 land. Henderson's observations had actual precedence 

 in point of time, but Bessel's measurements were so 

 much more numerous and authoritative that he has 

 been uniformly considered as deserving the chief credit 

 of the discovery, which priority of publication secured 

 him. 



By an odd chance, the star on which Henderson's ob- 

 servations were made, and consequently the first star 

 the parallax of which was ever measured, is our nearest 

 neighbor in sidereal space, being, indeed, some ten bill- 

 ions of miles nearer than the one next beyond.. Yet 

 even this nearest star is more than two hundred thou- 

 sand times as remote from us as the sun. The sun's 

 light flashes to the earth in eight minutes, and to Nep- 

 tune in about three and a half hours, but it requires 

 three and a half years to signal Alpha Centauri. And 

 as for the great majority of the stars, had they been 

 blotted out of existence before the Christian era, we of 

 to-day should still receive their light and seem to see 

 them just as we do. When we look up to the sky, we 

 study ancient history ; we do not see the stars as they 

 are, but as they were years, centuries, even millennia 

 ago. 



The information derived from the parallax of a star 

 by no means halts with the disclosure of the distance of 

 that body. Distance known, the proper motion of the 

 star, hitherto only to be reckoned as so many seconds of 

 arc, may readily be translated into actual speed of prog- 



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