58 The Planet Saturn. 



of hardihood, not to say presumption, for any but a great 

 leader in science to call it in question now. But truth ought 

 to be paramount to such considerations. It is not authority 

 but fact with which we have to deal. It is not so much a 

 matter of opinion as of evidence, and a circumstantial examina- 

 tion of the original observations seems to bring" with it the 

 inevitable impression that they are not adequate to bear out 

 the conclusion which has been drawn from them. The lucid 

 points which have been so often noticed, strung like beads, 

 to use IjPs elegant illustration, upon the ring, may be referred 

 to more than one cause. If fixed, the reasoning of Olbers and 

 the measurements of Bond concur to prove that they are 

 merely perspective foreshortenings or transmitted glimpses of 

 the brightest portions of the ring, and their frequent want of 

 symmetry offers, as we have seen, no insurmountable impedi- 

 ment to this explanation, in default of which they would be 

 irreconcilable with any rotation whatever. It is only among 

 such as are moveable that the indications of rotation can be 

 sought • of these the greater number are confessedly merely 

 satellites projected upon the line of the ring, and it remains to 

 be inquired whether there are any others which cannot be ac- 

 counted for in this way. Now, in 1 789, after the discovery of the 

 two innermost satellites, Ij[ found in the record of his observations 

 that in 47 instances, extending through 20 nights, he had seen 

 bright points not concurring with the position of any satellite 

 at the time. The idea of their being mere results of perspec- 

 tive, or openings in the dark side, had then never been sug- 

 gested, and he does not seem to [have contemplated the possi- 

 bility of their fixity : he therefore assumed the existence of 5 

 separate spots — which he preferred to consider as outbreaks of 

 fire rather than as mountains — in different positions on the 

 ring ; and he proceeded to show that his observations might 

 all be accounted for by a combined rotation of these hypotheti- 

 cal spots in rather more than 10£ hours. This, it may be 

 safely asserted, is a mode of proof which is entitled to little 

 confidence. But, it will be asked, did he not actually witness 

 their motion ? That, it is obvious, would be the only satisfac- 

 tory test. A point on a ring revolving with such rapidity 

 would be carried through its whole apparent length in 5.j hours, 

 or through a space equal to the radius of the planet in about 

 lh. 10m., and, though considerable allowance must be made 

 for the perspective foreshortening of the direction of motion, 

 it is evident that among so many observations it ought to 

 have been repeatedly perceived. But in two instances only is 

 anything of the kind distinctly specified. Oct. 30, 20h. 53m. 

 distance ± diam. of planet/ (but this he is obliged to refer to 

 a different hypothetical spot) : — 23h. 55m. § ditto p, very near 

 the end of the arm : — Oh. 42m. a little nearer than before : — 



