226 HERSCHEL AND HIS WORK 



surrounded by a luminous atmosphere, may be looked 

 upon as so many opaque, habitable, planetary globes ; 

 differing, from what we know of our own planets, 

 only in their size, and by their intrinsically luminous 

 appearance. They also, like the planets, shine with 

 differently coloured light. That of Arcturus and 

 Aldebaran, for instance, is as different from the light 

 of Sirius and Capella, as that of Mars and Saturn is 

 from the light of Venus and Jupiter. A still greater 

 variety of coloured star-light has already been shewn 

 to exist in many double stars, such as y Andromedse, 

 (3 Cygni, and many more. In my sweeps are also 

 recorded the places of 9 deep garnet, 5 bright garnet, 

 and 10 red coloured stars, of various small magnitudes 

 from the 7th to the 12th. 



" By some experiments on the light of a few of the 

 stars of the 1st magnitude, made in 1798, by a prism 

 applied to the eye-glasses of my reflectors, adjustable 

 to any angle, and to any direction, I had the following 

 analyses : 



" The light of Sirius consists of red, orange, yellow, 

 green, blue, purple, and violet. 



" a Orionis contains the same colours, but the red is 

 more intense, and the orange and yellow are less 

 copious in proportion than they are in Sirius. 



" Procyon contains all the colours, but proportionally 

 more blue and purple than Sirius. 



"Arcturus contains more red and orange and less 

 yellow in proportion than Sirius. 



"Aldebaran contains much orange, and very little 

 yellow. 



" Lyrse contains much yellow, green, blue, and 

 purple." 



