THE PLANETS, ARE THEY INHABITED \ 



The vertex or highest point of this arch will be upon his meri- 

 dian, and the two portions into which it will be divided by the 

 meridian will be equal and similar, and will descend to the 

 horizon at points equally distant from the meridian. The 

 apparent breadth of this illuminated bow will be greatest upon 

 the meridian, and it will decrease in descending on either side 

 towards the horizon, where it will be least. The division between 

 the two rings will be apparent, and, except at places within a 

 very short distance of the equator, the firmament will be visible 

 through it. 



The distance of the edge of the bow from the celestial equator 

 will not be everywhere the same, as it has been erroneously 

 assumed to be. That part of the bow which is upon the meridian 

 will be most remote from the celestial equator ; and in descend- 

 ing from the meridian on either side towards the horizon, the 

 decimation of its edge will gradually decrease, so that those 

 points which rest upon the horizon will be nearer to the equator 

 than the other points. 



15. Some idea may be formed of the varieties of appearance 

 presented by the ring to observers in different latitudes of the 

 planet, by imagining an observer starting from that Saturnian 

 pole which is on the same side of the ring as the sun, to travel 

 along a meridian towards the equator. At first the convexity of 

 the planet will intercept all view whatever of the ring, and 

 this, as has been shown in the memoir already referred to, will 

 continue until he has descended below the latitude 63 20' 38". At 

 this latitude the ring will just touch his horizon, and will 

 continue to be more and more seen until he descends to latitude 

 47 33' 51", when both rings will be seen as represented in fig. 9. 



Fig. 10. 



In descending to lower latitudes, more and more of the rings 

 will rise above the horizon, and they will assume the form of a 

 double bow, as represented in fig. 10. 



As the observer descends lower and lower in latitude, the bow 

 60 



