4 ,66 Dr. Hersci-iel’s Observations and Remarks on the 
Saturnian year, and the gradual change of the colour of the 
polar regions seems to be in a great measure ascertained. 
Should this be still more confirmed, there will then be some 
foundation for admitting these changes to be the consequence 
of an alteration of the temperature in the Saturnian climates. 
And if we do not ascribe the whiteness of the poles in their 
winter seasons immediately to frost or snow, we may at least 
attribute the different appearance to the greater suspension 
of vapours in clouds, which, it is well 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 Saturnian years, and this, on 
account of their extraordinary length, can only be expected 
from the successive attention of astronomers. 
On the Atmosphere of Saturn . 
June 9, 1806. The brightness which remains on the north 
polar regions, is not uniform, but is here and there tinged 
with large dusky looking spaces of a cloudy atmospheric 
appearance. 
From this and the foregoing observations on the change 
of the colour at the polar regions of Saturn arising most pro- 
bably from a periodical alteration of temperature, we may 
infer the existence of a Saturnian atmosphere ; as certainly 
we cannot ascribe such frequent changes to alterations of the 
surface of the planet itself : and if we add to this considera- 
tion the changes I have observed in the appearance of the 
