S* M. O. A. Rosenberger on the Elements 



correcting the co-ordinates of the comet with reference to the 

 equator, on account of the changes of ?j and i; a mode which 

 I preferred as rather more convenient for calculation. In 

 order, however, to obtain an approximate view of the change 

 of the apparent place of the comet by the effect of the dis- 

 turbances, it will suffice to notice that they increase the right 

 ascension and declination of the comet on 



January 22 by + 0-01 and +0"03 



February 5 +0-13 +0-04. 



March 31 + 0*60 — 1-64- 



April 6 +1-20 -2-54. 



13 + 2-40 —5-04. 



16 + 3-25 -7-71 



30 —19-65 +8-68 



May 9 — 7-09 +1-83 



19 - 5-13 +1-60 



June 4 — 4.-24 +1-65 



The places of the ephemeris were then changed, by the ap- 

 plication of precession and nutation, into apparent places, 

 and closely compared with the newly reduced observations. 

 With regard to the reduction of the observations, it is to be 

 observed that the places of the compared stars have been 

 taken (wherever it was possible) from the Fundmnejita Astro- 

 nomice, or from Piazzi's Catalogue. For stars not found there, 

 and for those only, I used the Histoire Celeste, and Bes.sel's2onfs, 

 and wherever it was feasible, I took the mean of both according 

 to the number of the observations. Severa"! stars, which are 

 no where determined, Professor Bessel kindly undertook to 

 determine for me. After all, I was obliged to pass over a few 

 observations, either from a want of a fixed determination of 

 the compared stars, or because the statements of the observer 

 Were falsified through errors of the press or of the pen. Be- 

 sides the parallaxes,the influence of refraction upon micrometer 

 observations was everywhere taken into account. 



As the comparison of the observations with the ephemeris 

 distinctly showed that the observations of the different astrono- 

 mers could not be received with equal confidence, and wish- 

 ing to come as near the truth as possible, I resolved to take into 

 account each individual observation according to the method of 

 least squares, so that all observations of the same kind could 

 be treated together, and their mean errors discovered with 

 some degree of proximity. At the same time the right ascen- 

 sions given by each observer were separated from the declina- 

 tions, since the former depend on the observed transits of the 

 comet, and deserve much more confidence than the declina- 

 tions. 



