THE PLANET JUPITER IN OCT. AND NOV. 1880. 
11 
in their apparent positions, and it is manifestly impossible to 
combine tbe observations of several nights because tbe objects 
bave in tbe meantime undergone a great displacement in their 
relative places. Let any observer execute a careful sketch of 
tbe planet when tbe red spot is on the central meridian, and 
then, three or four nights later, make a similar drawing. He 
will, on comparing them, find they are utterly incompatible. 
Tbe objects which in bis first sketch were immediately adjacent 
to tbe red spot, are seen considerably in advance of it (towards 
tbe western limb), while others, which in bis previous observa- 
tions were between tbe centre and east limb are now lying 
directly under tbe red spot. Such facts bave to be carefully 
considered by observers of Jovian phenomena, hence their 
sketches are necessarily hurried and often imperfect in de- 
tails. 
We bave been particular in describing these observations of 
spots on Jupiter , because tbe phenomena so distinctly exhibited 
by them must obviously command tbe attention of every one 
interested in inquiries connected with tbe physical condition of 
tbe Jovian planet. Tbe singular diversity of appearance and 
motions which bave been pointed out, must be eagerly traced in 
their future sustenance and development ; and it is of happy 
augury, as indicating tbe interest centred in tbe subject and 
tbe probability of its successful investigation, that so many ob- 
servers are now devoting a share of their time to tbe work. 
Tbe acquisition of numerous records that must accrue from 
many independent sources will possess considerable value, and 
be tbe means of eliminating such errors as are unavoidable 
in observations of meagre character. 
Mr. Dennett at Southampton, Mr. Williams at Brighton, 
and tbe writer at Bristol, simultaneously pointed out tbe evi- 
dences of rapid proper motions in tbe dark spots recently ob- 
served ranged along a belt in tbe northern hemisphere of Jupiter. 
Tbe white spot just south of tbe planet’s equator was detected 
by tbe writer on September 18, and it came under general obser- 
vation after November 17. Mr. H. Corder at Chelmsford has 
re-examined it on many occasions, and noted its transits across 
tbe central meridian of Jupiter. He bad been previously led to 
infer tbe motion of tbe ‘ white ovals ’ on tbe equator from ob- 
servations with a 4J-inch reflector in tbe autumn of 1879, and 
bad given a summary of bis observations in tbe Observatory for 
December of that year. From certain changes of position which 
be remarked on succeeding nights, be concluded that, relatively 
to tbe red spot, they completed a circuit of tbe planet in about 
forty days. 
In conducting bis recent observations, tbe writer has not 
paid special regard to tbe appearances of tbe satellites. Their 
