62 THE ORBIT OF NEPTUNE. 



as mucli weight as those of any other observatory. This has been effected by 

 applying the constant correction — 0'.04 to all the results before combining 

 them. 



Anomalies somewhat similar are exhibited by the Paris declinations from 1860 

 to 1861, and by the Washington declinations of 1861. In the case of Wash- 

 ington, they may be accounted for by the circumstance that the systematic cor- 

 rections for 1861 depend mainly on observations made in 1863, very few declina- 

 tions of fundamental stars being observed in 1861-62. But it does not seem so 

 easy to account for the discrej)ancy between the Paris and Greenwich results. 

 A comparison of them shows that while the Paris observations systematically 

 place the ten fundamental stars adopted as our standard about 0".8 farther north 

 than Greenwich, their positions of Neptune, and of some small stars near the 

 equator, substantially agree. 



§ 28. The preceding normal right ascensions and declinations are next con- 

 verted into apparent ecliptic longitudes and latitudes, for the purpose of com- 

 parison with the provisional theory. For this purpose Hansen's obliquity of the 

 ecliptic has been adopted, so as to agree with the motion of the ecliptic adojjted 

 in the preceding chapter. In the following table we give for each date — 1. The 

 longitude from observation, obtained as just stated. 2. The seconds of longitude 

 from provisional theory, as given on p. 43. 3. The excess of the theoretical 

 over the observed longitude. 4, 5, 6. The corresponding quantities relative to 

 the latitude. 



