STRUCTURE OF SATURN'S KINGS. 



opposition. The Saturnians, therefore, have the advantage over 

 the Joviaus of witnessing the frequently recurring spectacle of 

 several full moons in their firmament. 



4. The invention of the telescope having invested astrono- 

 mers with the power of approaching, for optical purposes, hun- 

 dreds of times closer to the objects of their observation, one of 

 the earliest results of the exercise of this improved sense was the 

 discovery that the disc of Saturn differed in a remarkable 

 manner from those of the other planets in not being circular. 

 It seemed at first to be a flattened oblong oval, approaching to 

 the form of an elongated rectangle, rounded off at the corners. 

 As the optical powers of the telescope were improved, it assumed 

 the appearance of a great central disc, with two smaller discs, 

 one at each side of it. These lateral discs, in fine, took the 

 appearance of handles or ears, like the handles of a vase or jar, 

 and they were accordingly called the ansse of the disc, a name 

 which they still retain. At length, in 1659, Huygens explained 

 the true cause of this phenomenon, and showed that the planet 

 is surrounded by a ring of opaque solid matter, in the centre of 

 which it is suspended, and that what appear as ansae are those 

 parts of the ring beyond the disc of the planet at either side, 

 which by projection are reduced to the form of the parts of an 

 ellipse near the extremities of its greater axis, -and that the 

 open parts of the ansse are produced by the dark sky visible 

 through the space between the ring and the planet. 



The improved telescopes, and greatly multiplied number and 

 increased zeal and activity of observers, have supplied much 

 more definite information as to the form, dimensions, structure, 

 and position of this most extraordinary and unexampled 

 appendage, 



It has been ascertained that it consists of an annular plate 

 of matter, the thickness of which is very inconsiderable compared 

 with the superficies. It is nearly, but not precisely, concentric 

 with the planet, and in the plane of its equator. This is proved 

 by the coincidence of the plane of the ring with the general 

 direction of the belts, and with that of the apparent motion of 

 the spots by which the diurnal rotation of the planet has been 

 ascertained. 



When telescopes of adequate power are directed to the ring 

 presented under a favourable aspect, dark streaks are seen upon 

 its surface similar to the belts of the planet. One of these 

 having been observed to have a permanence which seemed incom- 

 patible with the admission of the same atmospheric cause as 

 that which has been assigned to the belts, it was conjectured 

 that it arose from a real separation or division of the ring into 



E2 51 



