Professor Ham ilton s Address. 



429 



may, indeed, be said with truth, that astronomical tables do not err now 

 by so much as whole minutes from the heavens ; but if those tables differ 

 by more than five seconds now, by using all the present means of accu- 

 rate reduction, from a well-observed opposition of a planet, for example, 

 their error is as manifest and certain now as an error exceeding a minute 

 was, in a former state of astronomy — and the discrepancies between the 

 present tables and observations are not uncommonly outside that limit. 

 The case is doubtful. Errors of observation to such amount they cannot 

 be ; and, therefore, they can only arise from some wrong method of re- 

 duction, or wrong-assumed elliptic elements or masses of the planets, or 

 insufficiently developed formulae of perturbation, or else they point to 

 some disturbing cause, which still remains obscure, and has not yet been 

 reached by the light of theory. But it ought surely to be deemed the 

 highest problem of astronomy, to examine with the utmost diligence into 

 that which has been often' said, but not as yet in every case sufficiently 

 established, whether theory and experience do really always agree. 

 When the solution of his weighty problem shall have been most studiously 

 made trial of, in all its parts, then either will the theory of Newton be 

 perfectly and absolutely confirmed, or else it will be known beyond all 

 doubt that in certain cases it does not suffice without some little change, 

 or that besides the known disturbing bodies there exist some causes of 

 disturbance still obscure/' And then, after some technical remarks, less 

 connected with our present subject, Bessel goes on to say, " to me, 

 considering all these things together, it appears to be of the highest mo- 

 ment (plurimum valere) towards our future progress in the knowledge of 

 the solar system, to reduce into catalogues as diligently as can be done, 

 according to one common system of elements, the places of all the planets 

 observed since 1750, than which labour, I believe, that no other now will 

 be of greater use to astronomy" — {Quo labore nullum credo nunc majorem 

 utilitatem Astronomice allaturum esse.) Such is the opinion of Bessel ; 

 but such is not the opinion of an anonymous censor, who has written of 

 us in a certain popular review. To him it seems a matter of little mo- 

 ment that old observations should be reduced. Nothing good, he 

 imagines, can come from the study of those obsolete records. It may be 

 very well 'that thousands of pounds should continue to be spent by the 

 nation, year after year, in keeping up the observatory of Greenwich, but 

 as to the spending L.500 in turning to some scientific profit the accumu- 

 lated treasures there, that is a waste of public money, and an instance of 

 misdirected influence on the part of the British Association. For you, 

 gentlemen, will rejoice to hear, if any of you have not already heard it, 

 and those who have heard it already will not grudge to hear it again, 

 that through the influence of this Association what Bessel wished, rather 

 than hoped, is now in process of accomplishment ; and that, under the 

 care of the man who in England has done most to shew how much may 

 be done with an observatory, that national disgrace is to be removed of 

 ignorance or indifference about those scientific treasures which England 

 has almost unconsciously been long amassing, and which concern her as 

 the country of Newton and the maritime nation of the world ; for the 

 spirit of exactness is diffusive, and so is the spirit of negligence. The 

 closeness, iudeed, of the existing agreement between the tables and the 

 observations of astronomers is so great, that it cannot easily be conceived 

 by persons unfamiliar with that science. No theory has ever had so 

 brilliant a fortune, or ever so outrun experience, as the theory of gravita- 

 tion has done. , But if astronomers ever grow weary, and faintly turn 

 back from the task which science and nature command, of constantly 

 continuing to test even this great theory by observation, if they put any 

 limit to the search, which nature has net put, or are content to leave any 

 difference unaccounted for between the testimony of sense and the^results 

 VOL. XIX. NO. XXXVIII. OCTOBER 1835. F f 



