some Stars towards or from the Earth. 143 



line in the star. The air was unfavourable on all the evenings of 

 comparison ; a rough estimate gives a velocity of from 30 to 35 per 

 second. The earth's motion was 18 miles, leaving from 12 to 17 

 miles for the velocity of recession between the star and the sun. 



/3 andlLeonis. — These stars were compared with hydrogen ; they 

 appear to be moving from the earth, but the want of steadiness in the 

 air prevented me from making a satisfactory estimate of their velocity. 

 I suspected their motion to be rather smaller than that of Regulus. 



ft 7> %> £> C TJrsee majoris. — All these stars have similar spectra, in 

 which the line F is strong, though there are small differences in the 

 breadth of the line. They were compared with hydrogen, and appear 

 to be moving from our system with about the same velocity. Pro- 

 bably their motion may be taken to be not far from 30 miles per 

 second. The earth's motion at the time of observation was from 9 

 miles to 1 3 miles from these stars, leaving a probable velocity of reces- 

 sion of 17 to 29 miles per second. In the case of the double star £, 

 the spectrum consisted of the light of both stars. 



7] JJrscG majoris was also compared with hydrogen. I believe it 

 shows a motion from the earth ; but the observations of this star are 

 at present less satisfactory. 



a Virginis and a Corona borealis. — These stars were compared 

 with hydrogen. I suspect that they are receding, but I have not 

 had nights sufficiently fine to enable me to make satisfactory ob- 

 servations of these stars. 



In addition to these stars some observations (which are less satis- 

 factory on account of the unfavourable state of the weather at the 

 time) appear to show that the stars Procyon, Capella, and possibly 

 Aldebaran are moving from the earth. 



The stars which follow have a motion of approach. 



Arcturus. — In the spectrum of this star the lines of hydrogen, of 

 magnesium, and of sodium are sufficiently distinct for comparison. 

 I found the comparison could be most satisfactorily made with mag- 

 nesium. 



The bright lines of magnesium fall on the less refrangible side 

 of the corresponding dark lines in the star's spectrum, showing 

 that the star is approaching the earth. I estimated the shift at about 

 •J- to \ of the interval between Mg 2 and Mg 3 ; this amount of dis- 

 placement would indicate a velocity of approach of 50 miles per 

 second. To this velocity must be added the earth's orbital motion 

 from the star of 5*25 miles per second, increasing the star's motion to 

 55 miles per second. 



When I can get favourable weather, I hope to obtain independent 

 estimations from the lines of sodium and of hydrogen. 



a Lyres. — In the spectrum of Vega the line corresponding to 

 H (3 is strong and broad. Comparisons were made on several nights, 

 but on one evening only was the air favourable. The observations 

 are accordant in showing that the narrow bright line from a Geissler's 

 tube falls on the less refrangible side of the middle of the line in the 

 star, thus leaving more of the line on the side towards the violet. 

 The estimations give a motion of approach between the earth and 



