On the other hand, _after_ opposition, (i.) the shadows travel _behind_ the satellites in transiting the disc; (ii.) the satellites are occulted by the _disc_; (iii.) they reappear from eclipse in Jupiter's _shadow_.
Conjunctions of the satellites are common phenomena, and may be waited for by the observer who sees the chance.

An eclipse of one satellite by the shadow of another is not a common phenomenon; in fact, I have never heard of such an eclipse being seen.

That a satellite should be quite extinguished by another's shadow is a phenomenon not absolutely impossible, but which cannot happen save at long intervals.
The shadows are not _black spots_ as is erroneously stated in nearly all popular works on astronomy.

The shadow of the fourth, for instance, is nearly all penumbra, the really black part being quite minute by comparison.

The shadow of the third has a considerable penumbra, and even that of the first is not wholly black.