THE PLANET JUPITER IN OCT. AND NOV. 1880. 
9 
these spots and the differences which their discordant motions 
have originated : — - 
Date. 
Red spot. 
White spot. 
Difference. 
Nov. 2 
h m 
10 26 
h m 
14 15 
+ 
h m 
3 49 
Nov. 3 
6 12 
9 47 
+ 
3 35 
Nov. 8 
5 21 
7 48 
+ 
2 27 
Nov. 17 
7 44 
8 14 
+ 
0 30 
Nov. 19 
9 23 
9 23 
+ 
0 0 
Nov. 20 
5 14 
5 2 
— 
0 12 
Nov. 21 
11 4 
10 41 
— 
0 23 
Nov. 27 
6 0 
4 19 
— 
1 41 
Nov. 28 
11 49 
9 51 
— 
1 58 
Nov. 29 
7 40 
5 27 
— 
2 13 
Thus, on November 2nd, the white spot followed the red by 
3 h 49 m , but, gradually drawing up to it, the interval decreased 
until November 19th, when the two objects mutually inter- 
sected the meridian at 9 h 23 m . After this the white spot pre- 
ceded by a distance rapidly accumulating, so that when I last 
observed both the spots, on November 29th, the interval 
separating them had become 2 h 13 m ; the daily excess of velo- 
city of the white spot compared with the red had been 13-J- 
minutes for the period included in the dates November 2-29, 
and slightly more than that (13 minutes), deduced from the 
whole series of observations from September 18th to December 
3rd, referred to above. 
It should be mentioned that in the sketches the objects are 
in each case represented as seen in an inverting telescope, so that 
the planet’s east limb appears on the right-hand side, and the 
northern hemisphere is the lower hemisphere as depicted in the 
figures. 
It is satisfactory to know that the singular white spot has 
been observed pretty frequently, and that it will be carefully 
watched as it successively becomes favourably presented on the 
disc of Jupiter. It is undoubtedly liable to great variations of 
brightness, and the light spots in its close neighbourhood have 
been noticed several times to alternately appear and disappear 
at remarkably short intervals. Indeed the effect produced has 
been something similar to that of dark clouds sweeping over 
brightly luminous regions ; and the mere fact of recurrence of 
identical markings on the Jovian disc, leads to the inference 
that such phenomena are referable to atmospheric origin. It 
is impossible to conceive that such immense changes can occur 
on the real surface of the planet. They must be attributable 
to a rapidly variable envelope, influenced by swift currents and 
opposing forces, so that its density and thickness become 
thereby affected and the sunlight reflected in different degree. 
