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HISTORY OF PHYSICAL ASTRONOMY.

who have any practical knowledge of astronomy. They are addressedespecially to the general reader, who might be led by misrepresentationto form inaccurate views on the subject. Men of science have all beendelighted and astonished that the planet was discovered so soon. Onlythose who make the cause of science subservient to the miserable grati-fication of personal feeling have sought to indulge in opprobrious language,because the discovery did not take place sooner. Such persons, true totheir instincts, would have been the first to hold up to public ridicule thecredulity of the planet hunters, and to raise the charge of a wastefulexpenditure of the country’s resources, if the speedy discovery of thedisturbing body had not indicated a different, though equally unjustifiable,ground of obloquy.

It would be an invidious task to institute a comparison between thorespective merits of Le Verrier and Adams in connexion with the immortaldiscovery, of which we have endeavoured to give some account in the pre-ceding pages. We are of opinion that the labours of both these geometersare equalty calculated to excite admiration. The annals of science donot contain a brighter page than that which records the progress of M.Le Vender's labours as lie advances from the ill-defined irregularities ofUranus to the precise position of the undiscovered planet. The carewith which he scrutinizes every fact; the vigilance lie exhibits in de-tecting every imaginable source of error, and the thorough manner in whichlie sifts all its parts; the ingenuity and conclusiveness of his methods,and his indomitable perseverance in calculation—indicate, in a high degree,the possession of those qualities which constitute the main elements ofsuccess in all researches relating to the physico-mathematical sciences.Nor does a review of Mr. Adams’ labours offer a less pleasing picture. Wosee the obscure undergraduate, while his attention is yet distracted by theroutine of academic discipline, seizing with the happy intuition of genius thotrue theory of Uranus , and forming the bold resolution of tracing it to itsfinal results. The constancy with which he afterwards struggles to effectthis object, notwithstanding the manifest disadvantages of his position, isequalled only by the masterly character of liis analytical researches andthe brilliant termination to which he conducts them. It is gratifying toreflect that the labours of both Le Verrier and Adams, in connexion withthe perturbations of Uranus , are so completely dissociated, that no dangerof a mis-statement of facts can exist in the discussion of their relativemerits. Differences of opinion on this last point will, no doubt, alwaysprevail; but we are confident that future ages will concur with the presentin awarding to each geometer the tribute of unqualified admiration.

The discovery of the planet Neptune (for such is the name by whichAstronomers have agreed to distinguish the Trans-Uranian member ofthe Solar System ) marks an important epoch in the history of physicalastronomy. Hitherto the object of the geometer had been to unfold by adeductive process the principles of perturbative influence, and to explainby them the various phenomena of the planetary motions. It was only inthe determination of the masses of the planets, and in assigning the ratiosof their polar and equatorial axes, that the order of inquiry was reversed,and an accurate knowledge of the disturbing influence was sought to beestablished by reasoning upwards from its observed effects. In each ofthese cases, however, the equations of condition are of extreme simplicity,and the value of the final results is dependent much less upon the skill ofthe geometer than upon the accuracy of the fundamental observations. Theidea of submitting to a similar treatment the problem of three bodies does