364. POPULAR SCIENCE MONTHLY. 



similarity ; but the greatest difficulty comes when we consider the 

 effect of the rings. 



At first thought it might seem that the rings would have little 

 to do with the climate of the planet, and in fact such is the case 

 during the summer of either hemisphere ; but winter tells a dif- 

 ferent tale, as we shall see. Since the rings lie exactly in the 

 plane of the planet's equator, they will be presented edgewise to 

 the sun at the equinoxes, when the sun is " vertical over the equa- 

 tor." At this time their shadow, part of which must fall on the 

 planet, will lie directly on the equator, and presumably be about 

 as wide as the general thickness of the ring system, which is esti- 

 mated to be not more than one hundred miles. 



As the sun travels northward from the equinox, it is apparent 

 that the shadow will fall farther and farther south of the equator 

 until it has covered the whole southern hemisphere, save a por- 

 tion of the torrid zone where the light comes through the space 

 between the rings and the planet. After the summer solstice the 

 effects are reversed : the shadow retreats toward the equator, and 

 after the succeeding equinox the southern hemisphere will have 

 its summer undisturbed, and the northern hemisphere in turn will 

 have its long winter made still more dreary by this remarkable 

 daily eclipse of the sun. It thus appears that only in a relatively 

 narrow belt lying on either side of the equator would be likely 

 to occur climatic conditions approaching those with which we are 

 familiar. 



One often sees in articles on astronomy some reference to the 

 grandeur of the Saturnian heavens at night, where, in addition to 

 the starry host familiar to us all, would be the wonderful ring 

 spanning the sky as an arch of golden light, and eight moons in 

 their various phases. In a measure this is true, but it depends 

 upon circumstances. During the summer half of the year in 

 either hemisphere the illuminated side of the rings is, of course, 

 visible perhaps even faintly so in the daytime, as is the case 

 with our moon ; but when the twilight falls and the golden arch 

 shines forth in all its beauty against the darkness of the sky, it 

 must certainly be a sight which for grandeur surpasses any celestial 

 phenomenon known to us, save possibly a total eclipse of the sun. 



As soon as the sun has set, however, the shadow of the planet, 

 where it falls upon the rings, rises in the east and mars the 

 beauty of the arch as it travels across it during the short night 

 and disappears in the west at sunrise. At the summer solstice, 

 though, the sun rises high enough in the heavens, or, more cor- 

 rectly, the planet's axis is inclined far enough toward the sun to 

 bring the outer ring clear of the shadow, which then appears 

 somewhat conical in shape and reaches across the inner bright 

 ring nearly to the outer one. 



