234 Notices respecting New Books. 



ters into which the book is divided. The last three chapters are 

 taken up with discussions as to the physical constitution of the rings 

 (which Mr. Proctor uncompromisingly regards as a congeries of 

 minute satellites), of the great inequality, and of the habitability of 

 Saturn. 



It is plain, from the above brief summary, that a great many things 

 contained in the book would apply with slight variation to other 

 planets ; but even in these respects there is a considerable gain in 

 the way of distinctness when properties common to several planets 

 are discussed with reference to one. Saturn, however, possesses 

 numerous striking peculiarities which render it well worthy of sepa- 

 rate treatment. These are enumerated by Sir W. Herschel in an 

 admirable passage quoted by Mr. Proctor (pp. 60 & 61) : — "There 

 is not another object in the heavens that presents us with such a 

 variety of extraordinary phenomena as the planet Saturn ; a magni- 

 ficent globe encompassed by a stupendous double ring ; attended by 

 seven satellites; ornamented with equatorial belts; compressed at 

 the poles; turning on its axis; mutually eclipsing its rings and sa- 

 tellites, and eclipsed by them ; the most distant of the rings also 

 turning on its axis, and the same taking place with the furthest of 

 its satellites ; all the parts of the system of Saturn occasionally re- 

 flecting light to each other — the rings and moons illuminating the 

 nights of the Saturnian, the globe and moons illuminating the dark 

 parts of the rings, and the planet and rings throwing back the sun's 

 beams upon the moons when they are deprived of them at the time 

 of their conjunctions." 



We venture to think that the seventh chapter has been unfortu- 

 nately named. When a chapter is headed the " Habitability of 

 Saturn," we are led to expect a discussion of the question whether 

 the conditions requisite for the support of life exist in Saturn ; but 

 instead we are presented with an account of what would be more 

 fittingly termed the physical aspects presented to an imaginary inha- 

 bitant of Saturn — such as the variations of the force of gravity, the 

 amount of heat and light received from the sun, the lengths of the 

 Saturnian day and year, the appearance of the satellites and rings, 

 &c. : these and kindred topics form a very proper conclusion to the 

 work, but it is not quite fair to give them as a discussion of the 

 habitability of Saturn. The fact is, that the data for such a discus- 

 sion do not really exist; e. g. nothing, we believe, is known as to 

 the composition of Saturn's atmosphere. It might, for aught we 

 know, consist of nitrogen saturated with aqueous vapour ; and if by 

 any chance it did so, this, we suppose, would be conclusive as to the 

 question of Saturn's habitability. 



What sort of positive argument can be alleged to justify the pre- 

 valent belief in " Saturnians ''" ? Mr. Proctor answers, " when we 

 consider the analogy of our own planet, it seems impossible to doubt 

 that Saturn is inhabited by living creatures of some sort." We think, 

 on the contrary, that it is very possible to entertain doubts on the 

 subject, and, to tell the truth, we are inclined to regard the preva- 

 lent belief as little better than a prejudice. But putting that on one 



