382 



Mr. W. Huggins on the Spectra of the Sun. [May 14, 



the rising of the land in this part of Spitzbergen. I shall also, where the 

 rocks are hard enough for the purpose, bore along the shores as many 

 watermarks as possible, to give in the future sure data for the settling of 

 the same interesting question. 



If it were possible to obtain a good pendulum we also would make 

 pendulum observations, at least if the expedition remains in these regions 

 during the winter. 



P.S. The expedition will start from Gottenburg July the 15th. 



V.II. Further Observations on the Spectra of the Sun_, and of 

 some of the Stars and Nebulse, with an attempt to determine 

 therefrom whether these Bodies are moving towards or from the 

 Earth.'' By William Huggins, F.ll.S. Received April 23, 

 1868. 



(Abstract.) 



§ I. Introduction, 



The author states that at the time of the publication of the " Observations 

 on the Spectra of the Fixed Stars," made jointly by himself and Dr. W. 

 A. Miller, Treas. R.S., they w^ere fully aware that the direct comparisons 

 of the bright lines of terrestrial substances with the dark lines in the 

 spectra of the stars, which they had accomplished, were not only of value 

 for the more immediate purpose for which they had been undertaken, 

 namely, to obtain information of the chemical constitution of the invest- 

 ing atmospheres of the stars, but that they might possibly serve to reveal 

 something of the motions of the stars relatively to our system. If the 

 stars were moving towards or from the earth, their motion, compounded 

 with the earth's motion, would alter to an observer on the earth the re- 

 frangibility of the light emitted by them, and consequently the lines of 

 terrestrial substances would no longer coincide in position in the spectrum 

 with the dark lines produced by the absorption of the vapours of the 

 same substances existing in the stars. 



The method employed by them would certainly have revealed an altera- 

 tion of refrangibility as great as that which separates the lines D. They 

 had, therefore, proof that the stars which they had examined, among 

 others Aldebaran, a Orionis, /3 Pegasi, Sirius, a Lyree, Capella, 

 Arcturus, Castor, Pollux, w^ere not moving with a velocity which would be 

 indicated by such an amount of alteration of position in a line. 



Since, however, a change of refrangibility corresponding to that which 

 separates the components of D would require a velocity of about 196 miles 

 per second, it seemed to them premature to refer to this bearing of their 

 observations. The earth's motion, and that of the few stars of which the 

 parallax has been ascertained, would make it probable that any alteration 

 in position would not exceed a fraction of the change which would have 

 been observed by them. 



