1 62 SPECTRA OF STARS. PARTI. 



Groups of lines appear In the blue portion of the spec- 

 trum ; and these, by causing the predominance of the 

 red rays, may be the cause of the red colour which dis- 

 tinguishes the light of this planet.' 7 



All the stronger lines of the solar spectrum were 

 seen in the brilliant light of Venus ; but no additional 

 lines indicating an absorptive action of tlie planet's 

 atmosphere. 



The authors are of the opinion that in most of the 

 planets the light is probably reflected from clouds 

 floating at some distance from the surface, so that it is 

 not subject to the strong absorptive action of the lower 

 and denser strata of the planet's atmosphere, which, 

 like our own, are most effective in producing atmo- 

 spheric lines. 



The results of the observations on the fixed stars are 

 exceedingly interesting, for they show that their ele- 

 mentary constituents are similar, but not identical ; 

 and that although they contain many of the sixty-five 

 % terrestrial elements, there are probably new unknown 

 substances also. 



When seventy dark lines on the spectrum of the star 

 Aldebaran, and eighty on that of a Orionis (Betelgeux) 

 were compared with the bright lines on the spectra of the 

 vapours of a variety of the terrestrial simple elements, 

 'it was found that Aldebaran contained nine terrestrial 

 substances and a Orionis five : that is, there were only 

 nine out of seventy of the dark lines of Aldebaran coin- 

 cident with bright lines, and five out of eighty of those 

 of a Orionis. Yet the seventy and eighty dark lines 

 that were compared represented some of the strongest 

 only of the numerous lines which were seen on the 

 spectra of these stars. Some of those remaining were 

 probably due to the vapours of other terrestrial elements 



7 From further observations Mr. Huggins is of opinion that the red 

 colour of this planet is not due to its atmosphere, but is peculiar to certain 

 parts of its surface. 



