216 SATURN. 



or great mass, of Saturn. There may be an atmospheric shell of 

 extreme tenuous gases, but capable of carrying sparsely strewn 

 clouds surrounding a heavier nucleus, or how shall we account for 

 the various markings seen to cross his face, and these not perma- 

 nent, for they have been followed in their changing aspects, and 

 so have helped to a determination of the planet's rotation ? The 

 equatorial bright zone has disclosed the presence of white spots, or 

 areas, as if it were hot matter that had been flung up from within. 

 Two of these white areas are shown in the drawing as seen on 

 May 5th, 1896, at i2h. One appears to have been about 2^" and 

 the other about ^" in diameter, or about 10,000 and 16,000 miles 

 each respectively in horizontal diameter. Dark spots, too, were 

 seen in the N. temperate belt. A bright margin to preceding limb 

 was also seen and noted as the brightest portion of the planet ; 

 indeed, it could be described as luminous, almost suggestive of a 

 highly reflective atmosphere. This bright margin was estimated 

 at about |" of arc in w^idth, equalling about 2,145 n^iles. Spectro- 

 scopic examinations by Huggins show an atmosphere to Saturn 

 similar to that of Jupiter, while Janssen's indicates an aqueous 

 vapour. Vogel's spectrum analysis shows more atmospheric bands 

 on the ball than in the rings. Many of the varying features and 

 fluctuations of light noticeable on Jupiter's disc are to be seen in 

 Saturn's case ; but, of course, more feeble and difficult to glimpse, 

 as from the greater distance of Saturn from the Sun the centre of 

 his disc receives not quite one-third as much sunlight as does the 

 centre of Jupiter's disc. 



The excentric position of the ball of Saturn was next referred 

 to and shown in the drawing. While the top of the inverted 

 image could not be seen with certainty above or over the rings, the 

 bottom, or N, certainly protruded beyond, showing a northerly 

 displacement, it was thought, of about J" of arc, or equal to 2,145 

 miles. This excentricity of the ball is thought to be mathemati- 

 cally possible. The distance of the limb of the planet from both 

 ansae, it is said, has been seen to differ as much as ^ '^^ ^^^' ^^' 

 in other words, the space between the ball and the rings on the 

 eastern side has been found to measure some 2,145 ™iles wider 

 than on the western side. Galle, in 1684, was the first to observe 

 that the ball was not placed centrally in the rings, though he 



