398 PLANET SATURN. 



is to be noticed that the south pole of the planet had been 

 long exposed to the influence of the sijn, and the former 

 polar whitishness was no longer to be seen. 



Jan. 1 , 1794. The south polar regions are a little less 

 bright than the equatorial belt. 



Nov. 5, 1796. The space between the quintuple belt 

 and the northern part of the ring is of a bright white 

 colour. 



This seems to indicate that the whiteness of the northern 

 hemisphere of Saturn increases when there is less illu- 

 mination from the sun. 



May 6, 1806. The north pole of Saturn being now 

 exposed to the sun, its regions have lost much of their 

 brightness; the space a^out the south pole has regained 

 its former colour, and is brighter and whiter than the 

 equatorial parts. 



May 1 5. The south polar regions of Saturn are white; 

 those of the north retain also some whitishness still. 



May 18. With a magnifying power of 527, the south 

 polar regions remain very white. The equatorial parts 

 become of a yellowish tinge, and about the north pole 

 there is still a faint dusky white colour to be seen. 



June 3. The south polar regions are considerably 

 brighter than those of the north. 



These observations contrasted with those which were 



made when the south pole was in view complete nearly 



half a Saturnian year, and the gradual change of the 



colour of the polar regions seems to be in a great mea- 



^, , sure ascertained. Should this be still more confirmed, 



The changes -* 



correspond there will then be some foundation for admitting these 

 with winter changes to be the consequence of an alteration of the 

 the planet. temperature m the baturnian climates. And it we do not 

 ascribe the whiteness of the poles in their winter seasons 

 immediately to frost or snow, we may at least attribute 

 the diflerent appearance to the greater suspension of va- 

 pours in clouds, which, it is weir known, reflect more 

 light than a clear atmosphere, through which the opaque 

 body of the planet is more visible. The regularity of 

 the alternate changes at the poles ought however to be 

 observed for at least two or three of the Satnrnian years, 

 and this, on account of their extraordinary length, can 



only 



