194 Movements of Jupiter's Cloud -Masses. [April, 
egg-shaped clouds, set side by side, as every careful observer 
of Jupiter with high telescopic powers has from time to 
time perceived.* 
That these egg-shaped clouds are really egg-shaped — not 
merely oval in the sense in which a flat elliptic surface is 
oval — is suggested at once by their aspect. But it is more 
distinctly indicated when details are examined. It appears 
to me that considerable interest attaches to some observa- 
tions which were made by Mr. Brett, in April, 1874, upon 
some of the rounded spots then visible upon the planet’s 
equatorial zone. It will not be thought that I am disposed, as 
a rule, to place too much reliance upon the observations and 
theories of Mr. Brett, seeing that on more than one occasion 
I have had to call attention to errors into which, in my 
judgment, he has fallen. For instance, I certainly do not 
think he has ever seen the solar corona when the sun was 
not eclipsed, though I have no doubt he saw what he 
described, which he supposed to be the corona, but which 
was in reality not the corona. Nor, again, do I accept 
(though I do not think it worth while, to discuss) his theory 
that Venus has a surface shining with metallic lustre, and 
is surrounded by a glassy atmosphere ; though in that case, 
again, his description of what he saw may be accepted as 
it stands, and all that we need reject is his interpretation 
thereof. In the case of Jupiter’s white spots, Mr. Brett’s 
skill as an artist enables us to accept not only his observa- 
tions, but his interpretation of them, simply because the 
interpretation depends on artistic, not on scientific, con- 
siderations. 
“ I wish,” he says, “ to call attention to a particular 
feature of Jupiter’s disc, which ” [the feature probably 1 
“ appears to me very well defined at the present time, and 
which seems to afford evidence respecting the physical con- 
dition of the planet. The large white patches which occur 
on and about the equatorial zone, and interrupt the conti- 
nuity of the dark belts, are well known to all observers, and 
the particular point in connection with them to which I beg 
leave to call attention is that they cast shadows ; that is to 
* Webb thus describes the egg-shaped clouds : — “ Occasionally the belts 
throw out dusky loops or festoons, whose elliptical interiors, arranged length- 
ways and sometimes with great regularity, have the aspedt of a girdle of 
luminous egg-shaped clouds surrounding the globe. These oval forms, which 
were very conspicuous in the equatorial £one (as the interval of the belts may 
be termed) in 1869-70* have be@n seen in other regions of the planet* and are 
probably of frequent occurrence, The earliest distinct representation of them 
that t knPW sf is by Marsh but they isrs perhaps indicated if* 
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