THE STARS. 165 



directions of the infinite immensity, through the 

 boundless, bottomless abyss ; in a void for ever 

 open, ever yawning, ever black, and ever un- 

 fathomable ; during an eternity, without days, 

 without years, without centuries, or measures. 

 Such is the aspect, grand, splendid, and sublime, 

 of the universe which flies through space before 

 the dazzled and stupefied gaze of the terrestrial 

 astronomer, born to-day to die to-morrow, on a 

 globule lost in the infinite night." 



Measures of proper motion only enable us to 

 determine the motion of stars across the line 

 of sight. They do not tell us whether the 

 star is advancing or receding. Here, however, 

 the spectroscope comes to our aid by means of 

 Doppler's principle, described in the chapter on 

 the Sun. It occurred to Huggins that, by 

 observing the displacement of the lines in the 

 spectra of the stars, he could determine their 

 motion in the line of sight. His first results 

 were announced in 1868. In the case of 

 Sirius, the displacement of the line marked F 

 was believed to indicate a velocity of recess- 

 ion of 29 miles a second. Some time later 

 Huggins announced that Betelgeux, Eigel, 

 Castor, and Regulus were retreating, while 

 Arcturus, Pollux, Vega, and Deneb were ap- 

 proaching. Soon after this successful work the 



