OBSERVATIONS ON JUPITER IN 1870-71. 
279 
state of our own air, or, as often seemed to be the case, the 
lateral fusion of the luminous masses, did not reduce them to a 
state of feebleness and indecision. The elliptical areas were 
sometimes so luminous on their South, and shaded, apparently, 
on their North sides, that with a less powerful instrument they 
might readily assume an imperfect zone-and-belt aspect, and as 
such it may be suspected that they have been sometimes de- 
lineated. The size, though not the general form, of these areas 
and their intervals, as far as could be distinguished, varied in 
different parts of this coloured girdle. 
The South Temperate Zone , or rather its principal feature, 
the South Sub-torrid Belt , has undergone considerable change 
since 1869-70. At that epoch the belt assumed the form of a 
spiral, so gradually evolved as to be sensibly parallel to its torrid 
neighbour for a great part of its length, and dissipated before 
it reached the opposite side of the zone, or the meridian where 
it commenced ; leaving a vacancy which was occupied by the 
great ellipse of Grledhill and Mayer. In consequence of inter- 
ruptions, and especially of weather adverse to minute examina- 
tion, I never obtained satisfactory views of the whole of this 
zone ; but it appeared to me that after a certain degree of 
divergence, and subsequent parallelism as before, a curve of 
contrary flexure succeeded, and the belt returned to a junction 
with itself, a little beyond its origin. On another side of the 
globe, however, but how situated relatively to this intersection 
I cannot say, it exhibited an interesting feature in sending off 
a curved branch in a South-West direction across the zone, which 
extended convex towards South till it actually or very nearly 
merged in the South temperate belt. When once the air was 
exceptionally still (Dec. 22), it appeared to start from a small 
separate base, West of which was a bend in the original belt, 
and a minute very dark spot of perhaps 0 "*5. It was seen 
again with another spot on Jan. 25. The belt exhibited similar 
variations in breadth and darkness to those noticed in the pre- 
vious season, and frequently details of obviously an interesting 
character were too feeble for satisfactory vision or delineation. 
The South Temperate Belt varied greatly in aspect, being 
sometimes divided into two parallel streaks, of which one 
formed a companion to the sub-torrid belt ; at others broken 
up by white patches, which, from the general feebleness of the 
belt, were seldom very distinctly bounded. Not unfrequently 
it was so faint and diffused that very little could be made out,, 
and a general washy appearance extended from the sub-torrid 
belt even as far as the Pole. Occasionally, however, the South 
Polar Belt had an independent and tolerably conspicuous 
existence. 
Such have been the principal phenomena of this season. 
