308 NOTES TO BOOK VII. 



been calculated, and the planet conforms to the Tables 

 resulting from this calculation with as much exactness as 

 could be expected. A greater degree of agreement between 

 theory and observation may be expected when the effect 

 of the larger planets in disturbing the motion of the 

 smaller ones has been taken into account. 



(o.) p. 244. In speaking of Halley's Synopsis Astro- 

 nomicce Cometicce, Delambre says (Ast. xvia. Siecle, p. 130), 

 " Voila bien, depuis Kepler, ce qui on a fait de plus grand, 

 de plus beau, de plus neuf en astronomic." Halley, in 

 predicting the comet of 1758, says, if it returns, " Hoc 

 primum ab homine Anglo inventum fuisse non inficiabitur 

 aequa posteritas." 



(p.) p. 246. A third Comet of short period was dis- 

 covered by Faye, at the Observatory of Paris, Nov. 22, 

 1843. It is included between the orbits of Mars and 

 Saturn, and its period is seven years and three tenths. 



This is commonly called Fayes Comet, as the two 

 mentioned in the text are called EncJce's and Bielas. In 

 the former edition I had expressed my assent to the rule 

 proposed by M. Arago, that the latter ought to be called 

 Gambarfs Comet, in honour of the astronomer who first 

 proved it to revolve round the Sun. But astronomers 

 in general have used the former name, considering that 

 the discovery and observation of the object are more dis- 

 tinct and conspicuous merits than a calculation founded 

 upon the observations of others. And in reality, Biela 

 had great merit in the discovery of his Comet's periodicity, 

 having set about his search of it from an anticipation of 

 its return founded upon former observations. 



Also a Comet was. discovered by De Vico at Rome on 

 Aug. 22, 1844, which was found to describe an elliptical 



