ought, deeper than it appears through a telescope of
similar power on Earth. The seas were distinctly grey rather than
blue, especially when, by covering the greater part of the field, I
contrived for a moment to observe a sea alone, thus eliminating the
effect of contrast. The bands of Jupiter in their turn were more
notably distinct; their variety of colour as well as the contrast of
light and shade much more definite, and their irregularities more
unmistakable. A satellite was approaching the disc, and this afforded
me an opportunity of realising with especial clearness the difference
between observation through seventy or a hundred miles of terrestrial
atmosphere outside the object glass and observation in space. The two
discs were perfectly rounded and separately discernible until they
touched. Moreover, I was able to distinguish upon one of the darker
bands the disc of the satellite itself, while upon a lighter band its
round black shadow was at the same time perfectly defined. This
wonderfully clear presentation of one of the most interesting of
astronomical phenomena so absorbed my attention that I watched the
satellite and shadow during their whole course, though the former,
passing after a time on to a light band, became comparatively
indistinct. The moment, however, that the outer edge passed off the
disc of Jupiter, its outline became perfectly visible against the
black background of sky. What was still more novel was the occultation
for some little time of a star, apparently of the tenth magnitude, not
by the planet but by the satellite, almost immediately after it passed
off the disc of the former. Whether the star actually disappeared at
once, as if instantaneously extinguished, or whether, as I thought at
the moment, it remained for some tenth of a second partially visible,
as if refracted by an atmosphere belonging to the satellite, I will
not venture to say. The bands and rings of Saturn, the division
between the two latter, and the seven satellites, were also perfectly
visible, with a distinctness that a much greater magnifying power
would hardly have attained under terrestrial conditions. I was
perplexed by two peculiarities, not, so far as I know, hitherto [5]
mentioned by astronomers. The circumference did not appear to present
an even curvature.

I mean that, apart from the polar compression, the shape seemed as if
the spheroid were irregularly squeezed; so that though not broken by
projection or