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but in time it would get so far up toward the north pole that it would never set during a period equal to that at which it never rose.

The fact that all the satellites revolve in almost exactly the same plane gives some colour to this view, but does not quite prove it, because it is not impossible that their planes are kept together by their mutual action. If, however, this is the case, and if the equator of Uranus does not coincide with the orbits, the latter will, in the course of centuries, undergo a change which our successors will be able to determine. In this way they will be enabled to learn something of the equator and poles of Uranus, even if their telescopes are not powerful enough to afford any visual evidence on the subject.