Comets. 257 



state of the science. In fact, there is no branch of astronomy 

 more replete with interest, and we may add more eagerly 

 pursued at present, inasmuch as the hold, which exact calcu- 

 lation gives us on it may be regarded as completely esta- 

 blished ; so that whatever may be concluded as to the motions 

 of any comet which shall henceforward come to be observed, 

 will be concluded on new grounds and with numerical pre- 

 cision ; while the improvements which have been introduced 

 into the calculation of cometary perturbation, and the daily 

 increasing familiarity of numerous astronomers with compu- 

 tations of this nature, enable us to trace their past and 

 future history with a certainty, which, at the commencement 

 of the present century could hardly have been looked upon 

 as attainable. Every comet newly discovered is at once sub- 

 jected to the ordeal of a most rigorous inquiry. Its elements, 

 roughly calculated within a few days of its appearance, are 

 gradually approximated to as observations accumulate, by a 

 multitude of ardent and expert computists. On the least 

 indication of a deviation from a parabolic orbit, its elliptic 

 elements become a subject of universal and lively interest 

 and discussion. Old recoi'ds are ransacked, and old obser- 

 vations reduced, with all the advantage of improved data 

 and methods, so as to rescue from oblivion the orbits of 

 ancient comets which present any similarity to that of the 

 new visitor. The disturbances undergone in the interval by 

 the action of the planets are investigated, and the past, thus 

 brought into unbroken connexion with the present, is made 

 to afford substantial ground for pi'ediction of the future. A 

 great impulse meanwhile has been given of late years to the 

 discovery of comets by the establishment in 1840,* by His 

 late Majesty the King of Denmark, of a prize medal to be 

 awarded for every such discovery, to the first observer (the 

 influence of which may be most unequivocally traced in the 

 great number of these bodies which every successive year 

 has added to our list), and by the circulation of notices, by 

 special letter,t of every such discovery (accompanied, when 



* S'ft the announcement of tliis Institution in Astron. Nncli. No. 400. 

 t Hy I'rof. Schumacher, Director of the Royal Observatory of Altona. 



