228 Proceedings of the British Association for [Sept. 



system has not made all the progress which might have been expected 

 from the great number and goodness of the observations made on the 

 sun, and moon, and planets, from the time of Bradley down. It 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 live seconds now, by using- all the present means 

 of accurate reduction, from a well observed opposition of a planet — for 

 example, their error is as manifest and certain now as an error ex- 

 ceeding 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 reduction, 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 moment (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 labors 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 moment 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 J, 500 in turning to some scientific profit the accu- 

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

 instance of misdirected influence on the part of the British Associa- 

 tion. 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 associa- 

 tion 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 show 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 



