17 



Disturbed Elements II, as far as they could be completed at this time, are 

 here appended : 



DISTURBED ELEMENTS II. 



7f = unknown. 



SI = 129° 48' 23".2 M. eq. January 1, 1847. 



i = 1° 45' 19".9 



e = unknown. 



^. = 21".37881 



c = unknown. 



T = 165^9703 



p = 21".65789 



X = 326° 59' 34". 74 1847, September 30, m. noon Greenwich. 



No. 27. It is possible that the insertion in the conditional equations of two 

 more terms for the daily variations of r and . might have decided this point. 

 Before attempting this inquiry, it was concluded to examine the ancient cata- 

 logues, for the purpose of detecting Neptune as a missing star. Among the cata- 

 logues to be resorted to were Bradley's, Lacaille's, Mayer's, Lalande's, Piazzi's, 

 Bessel's, Brisbane's, and Taylor's. The first three of these catalogues do not 

 usually include stars of the magnitude 7.8. In the recent publication of Piazzi's 

 original observations by the Vienna Observatory, extending from 1792 to 1798, 

 I do not find among the stars observed by Piazzi, and not subsequently identi- 

 fied, any which come within reasonable limits of Leverrier's computed place on 

 the nights of observation. From 1821 to 1832, the term of Bessel's Zone 

 observations, Neptune was near the southern point of the Ecliptic, and conse- 

 quently below his limits. The Brisbane catalogue is chiefly confined to 

 stars of more than 30° of south declination. Taylor's observations at Madras 

 are usually limited to the reviewing of stars contained in previous catalogues. 

 There remained only Lalande's catalogue, which offered hopes of success at 

 present. 



I had expected that a list of stars, from the Histoire Celeste Frangais, in the 

 Neptunian region, on the nights of observation, would comprise a hundred or 

 more. 



No. 28. On the 2d of February were commenced the computations for the 

 formation of the trial catalogue. This was easily effected. After making a 

 sketch of the Neptunian regions for the dates from 1790 to 1800, I soon came 

 to the conclusion that the nights of the 8th and 10th of May, 1795, were the 

 only ones that afforded a reasonable prospect of furnishing an observation of 

 Neptune, and accordingly computed for the evening of the 10th of May, the 

 limits of the Neptunian region, or in other words the locus of Neptune as a 

 fixed star, referred to the apparent equinox of May 10, 1795, with the node, 

 inclination, orbital longitude, and radius vector of my Disturbed Elements 

 II, and various average angular motions from 21 ".3 to 21". 9, for the interval 



