EPHEMERIS OF NEPTUNE AND MERIDIAN OBSERVATIONS. 



59 



Professor Challis' observations give the following equations for the 

 difference between Observation and Ephemeris. 



Observation Ephemeris. 

 E. A. N. P. D. 



May 26 

 June i 



0-18 

 0-21 



+ 1-5 

 + 1-0 



I am hard at work on the perturbations of Uranus, in order to obtain 

 a new theoretical determination of the place.... The general values of the 

 perturbations are enormous, far exceeding anything else of the same kind in 

 the system of the primary planets. A comparison of the numerical expres- 

 sions for the perturbations which I have now obtained with those, which 

 I used before, would justify some scepticism as to former conclusions. But 

 we shall soon see how this great apparent difference affects the result. 



From the Astronomische Nachrichten, No. 616, pp. 241 244. 

 Ephemeris of Neptune for Greenwich Mean Midnight. 



