THE PLANET SATURN.

381

Or it might be that the San would rise uneclipsed at a pointof the horizon to the south of the arch of the ring b, as ats 3 in Fig . LXXXVII., and set in a similar manner; but, asthe dotted line s 3 s 3 shows, during a certain interval before andafter noon, be hidden by the arch. In this case there wouldbe a mid-day eclipse, just as in that previously described therewould be one in the morning and evening. Similarly, if theSun rose in an intermediate position well-immersed in thearch, it might undergo eclipse throughout the day.

Such phenomena might continue to occur day after day forlong consecutive periods. This may be proved, either by themethod we have just described, or, according to that firstmentioned, by calculating the size and position of the shadowof the rings upon Saturn . It may be shown that the shadowwould grow wider and wider upon the hemisphere on which itwould fall, while the planet would journey in its orbit from anequinox to a solstice ; and that it would, at the same time,gradually travel from the neighbourhood of the equator to-wards the polar regions, for a while leaving a considerableextent of surface nearer to the equator free from all eclipses.But, after the summer solstice of the hemisphere in question,the shadow would begin to travel back from the polar regions,while the eclipses, in moderately high latitudes, would he stillcontinuing.

For places situated upon the equator, the succession ofeclipses would be different from that which would be expe-rienced elsewhere, as may be understood by a consideration ofthe appearance which, as stated upon p. 378, the rings wouldthere present. In such a locality it would be the thickness andnot the breadth of the rings that would conceal the Sun ; andMr. Proctor has calculated* that, at each equinox, if thethickness of the inner ring b be supposed to be 100 miles,the Sun would be eclipsed all the day long, during a periodequal to about 9 - 6 of our days, or 22 Saturnian days; bothbefore and after which time there would be eclipses in themiddle of the day during a period equal to 20'35 of our days,or about 47 Saturnian days.

* See “ Saturn and its System,” p. 181, and Table XI., p. 224.