84 THE BORDERLAND OF SCIENCE. 



this world travels round Saturn, the orb of the latter 

 has a variable course on the Mimasian sky. Most per- 

 plexing are the relations thus presented. For Mimas 

 turns once on its axis in about six hours, and travels 

 once round Saturn in something short of twenty-three 

 hours ; so that even while Saturn is passing across the 

 Mimasian sky, he can be seen to traverse a large space 

 among the stars. X., who, as you know, is well versed 

 in terrestrial astronomy, expressed the opinion that 

 Mimasian astronomy must be difficult to master. 



However, the Mimasians, though good observers 

 (their instruments I shall describe on another occasion), 

 have as yet very imperfect ideas respecting astronomical 

 subjects. They suppose Mimas to be the centre of the 

 universe ; and though some of the more travelled 

 Mimasians maintain that Mimas is either a globe or a 

 cylinder in shape, yet the majority conceive that its 

 surface is quite flat. 



The ring of Saturn presents a very remarkable ap- 

 pearance in the Mimasian sky. It extends over an 

 enormous arc, insomuch that in certain Mimasian 

 latitudes when one end (or what looks like one end) of 

 the ring-system is on the horizon, the other is over- 

 head. The satellites composing the ring are not dis- 

 cernible from Mimas ; and as the ring where it crosses 

 the globe of Saturn cuts off a portion of his heat, 

 which they recognise with their heat-eyes just as 

 accurately as we should recognise the eclipse of a 

 portion of the sun, they call the ring the ' cool zone.' 

 Some of them very positively maintained, until of late, 



