T II K ORBIT OF U U A N U S. 



1 2fi 



rections were applied to his observed times of transit over the moan wire, and the 

 resulting time was employed as that of transit. Ivieh time, compared with the 

 computed right ascension of the star gave a \alue of the clock correction, which 

 was reduced to the time of transit of the planet by the known daily rate. If the 

 iii>truiiiental errors were always accurately determined, the mean of these clock 

 corrections would he used to obtain the right ascension of Uranus. But it was 

 frequently found that the clock error varied systematically with the declination of 

 tin- star, so that it was deemed advisable to add to the clock correction a term 

 varying as the simple declination, which was deduced from all the stars, and used 

 to reduce tin; correction to the parallel of Uranus. 



It was intended to give the results of this reduction for each observation, but 

 on comparing the results with those of Fleming in the Antroiioiniche Nuchrichten, 

 Band :JO, it appeared that the results were not materially better than his. It 

 does not, therefore, seem necessary to give more than the mean results for each 

 opposition. 



1 rom Bessel's declinations, with the old Gary circle, I was unable to obtain any 

 satisfactory results, owing, apparently, to a want of knowledge of some peculiarity 

 of the instrument. Fleming's reductions were therefore adopted. They are 

 designated by the letter Fin the following list. 



Mean Correct ions to the Provisional Ephcmeris given ly BesseVs Observations at 



KfaiyAerg, 1814-1829. 



Mean date. 



1822, June 24, 



1823, July 4, 



1824, July 6, 



1825, July 16, 



1826, July 18, 



1828, July 25, 



1829, Aug. 1, 



M'-:in date. 

 1M I, May 22, 

 1815, May 25, 

 1 M (5, May 27, 

 1.H17, June 6, 

 lsi8, June 8, 

 June 21, 

 June 23, 

 Total numbers of observations, 103. 



Results of Obscrvatims at various Glservatariex, from 1827 to 1829 inclusive. 

 During these three years we have, besides the observations already quoted, the 

 following: 



1. Observations by Schwerd, at Speier, of which the originals are given in 

 Axtronomisdie Beobachtungen angestellt mif der Sternwarte des Kiiniijl. Lyzeums in 

 Sli/er von F. M. Sdtwerd, Speyer, 1829-30, and of which the reduced results 

 are found in the Astronomische Nachrichten, Band 8, S. 264. 



2. The series by Airy, at Cambridge, commenced in 1828, and found in the 

 Cambridge Observations. 



3. Littrow's Vienna Observations, found in the first series of Annalen der K. K. 

 ,icarte in Wien. 



The mean corrections to the provisional ephemeris given by these ( scries are 

 shown in the following table. The observations have been divided in the usual 



