384

THE PLANET SATURN.

interfered with; since the shadows of the rings cannot fallupon those latitudes in winter, from which their bright sidewould not he seen in summer.

It is, however, a much more important fact that, at even somoderate a latitude as 36° from the equator of Saturn , theeclipses caused by the rings, when once they commence, con-tinue through the winter solstice without any pause until theyare done with, the shadow beginning to return again before itswhole width has passed across that and any higher latitude.And it is, we think, upon the whole, very clear that thisdiscussion strongly confirms our previous opinion against thehabitability of Saturn . Apart from many other difficultieswhich the supposition would involve, it seems that, except in acomparatively very narrow zone of the equatoreal regions, thelong duration of the eclipses caused by the rings would besufficient to prevent it, unless the inhabitants were periodicallyto migrate north and south, and in that way avoid the winterseasons. Fascinating as the ring-system is when seen in ourtelescopes, we may he very thankful indeed that none such ispossessed by the Earth . It appears to he replete with beauty toobservers at a distance; it would inevitably be a very un-pleasant obscurer of the Sun upon the planet itself.

We are then very glad that the Earth is a ringless planet .On the other hand, however, we might be very well content ifour Moon , the fair queen of our nocturnal skies, had one or twocompanions, or even rivals in her domain. This is the casewith Saturn ; for of such larger satellites as circle round it,outside the minute myriads which we believe to constitute itsrings, we know of eight.

We do not in any wise propose to discuss these Satelliteswith the same minuteness as those of Jupiter . Their muchgreater distance makes it impossible. Their eclipses, theirmutual occultations and perturbations, would no doubt be veryinteresting if seen from the planet; but they are, if not alto-gether beyond our ken, certainly beyond the limits of thislecture. We must be glad if we can even get so much as aglimpse of the smaller ones amongst the eight of whose ex-istence we are aware ; while it is very likely that others may