12 
POPULAR SCIENCE REVIEW. 
shadows have been several times noted crossing the disc as black 
spots of very distinct aspect, and Satellite I. has been 
seen, both by Mr. Corder and the writer, projected on the disc as a 
dusky spot. These 4 dark transits ' of the first satellite are 
somewhat rare, though it would appear that during the present 
opposition they have quite lost their exceptional character. 
The large extent of detail manifested on the surface of 
Jupiter has often impressed the writer with the necessity of a 
critical and searching review. There is a wide field here for patient 
labour and painstaking scrutiny. We have often heard of the 
vast amount of scenery on the lunar surface, and of the magnitude 
of the task involved in its complete delineation ; and we have 
been told by those who have laboured in the field of meteoric 
astronomy, of the multitude and variety of the meteor streams 
which the Earth annually intersects. Indeed, each of us has 
learnt, in his own department, to realize something of the 
stupendous nature of the subject to which our individual 
energies have been applied, and to admit that we can never hope 
to attain more than a very partial knowledge at the best. In 
the scenery of Jupiter and its swiftly- varying aspects, we may 
find another large field for exploration, holding out as rich a 
prospect of successful results as that of any other branch of 
astronomical research. 
Those who, during the last few months, have been engaged 
in examinations of Jupiter will frequently have turned their 
telescopes upon Saturn , situated not far to the eastward, and 
viewed his wonderful ringed sphere. It is true that this planet 
scarcely affords, from his greater distance, the same extent of 
detail as that perceptible upon the disc of Jupiter ; but the 
appearance of the ring amply compensates for whatever is 
wanting in other respects : and there is this to be said, that 
Saturn is commonly much better defined in a telescope than 
Jupiter. The brightness and glare attending the latter planet 
brings about an indistinctness which only the best conditions of 
atmosphere can fully eliminate ; while, in the case of Saturn , the 
moderation of lustre has the obvious effect of inducing the best 
performance of the telescope. This planet has lately been 
frequently subjected to careful inspection by the writer, and 
such features as could be discerned with certainty were noted 
down. The ring showed two divisions — one as a plain, black, 
curving streak, the other as an extremely faint line, not far from 
the outer extremity. The inner dusky (or crape) ring was also 
seen, and the exterior border of the outer bright ring seemed 
very dark, and where it was projected upon the planet, was visible 
as a dusky bar of shading, giving the impression that there is 
another dark ring lying closely outside the system of bright 
