To this testimony, coming from too high a source to be overlooked or disre- 

 garded, it may be added as an illustration of the success attending the labors of 

 American astronomers in this new and interesting field of research, ihat if, 

 during the historical periods of the observations, the Neptune of prediction, and 

 that of the Heavens, were conceived to form a double star, they would have 

 such close proximity that no telescope could separate them, even if it possessed 

 sufficient power to detect their duplicity. There is one circumstance which, 

 indeed, is not to be forgotten ; and that is, the great distance of the planet, 

 which prevents the small errors of the best theory of the earth (the point of 

 view of the Ephemeris) from sensibly affecting its projected place in the Hea- 

 vens, the impressed errors of the latter being only a thirtieth part of the former. 

 The experience of 1848 and 1849 shows, that for the case of a very remote 

 planet, it is possible, by the exercise of proper care, to compute an ephemeris 

 in advance, that shall surpass the whole season's work of a single observatory 

 in its close agreement with the average work of all. Mr. Walker's comparisons 

 of the Ephemeris with observations for these years will serve as a justification 

 of this remark. The meridian observations only have been used, with the 

 exception of Liverpool in 1849. 





Nation. 



Astronomer. 



Obs. — Eph. , for the opposition. 



Obs.— Eph., for the quadrature. 



Observatory. 



For R. A. 

 in arc. 



A a 



No. 



of 



Oba. 



For Doc. 



A 5 



No. 

 of 

 Oba. 



ForR.A. 

 in arc. 



A a 



No. 

 of 

 Obs. 



For Dec. 



A 5 



No. 

 of 

 Obs. 



1848. 

 Altona 

 Athens 

 Cambridge 

 Copenhagen 

 Durham 

 Hamburg 

 Konigsberg 

 Markree 

 Petersburg 



Denmark 

 Greece 



England 



Denmark 



England 



Germany 



E. Prussia 



Ireland 



Russia 



Petersen 



Bouris 



Challis 



Sievers 



Thompson 



RLimker 



Busch 



Graham 



Sawitsch 



II 



— 1.20 

 + 0.12 



— 089 

 + 2.52 



— 0.95 



— 0.95 

 + 0.81 



— 1.00 



— 1.22 



10 

 15 

 24 

 4 

 4 

 26 

 6 

 6 

 8 



II 

 + 0.41 

 + 0.61 

 + 1.97 



— 0.46 



— 1.29 



— 1.01 



— 0.46 

 + 1.40 



11 



15 



23 



3 



25 



6 



6 



8 



II 



— 0.56 



— 2.23* 



+ 0.29 



— 0.99 



— 0.80 

 + 0.33 



— 0.07 



— 0.32 



5 

 41 



11 



5 

 10 



3 

 23 



5 



// 



— 0.35 

 + 1.94* 



+ 1.40 



— 1.66 



— 0.76 

 + 0.19 



— 0.89 



5 

 41 



5 

 10 



3 

 23 



4 



Average for 1848 .... 



— 0.66 



103 



+ 0.28 



97 



— 0.56 



103 



+ 0.28 



91 



1849. 

 Altona 

 Hamburg 

 Liverpool 



Denmark 

 Germany 

 England 



Schumacher 



llumker 



Hartnup 



— 0.60 



— 1.45 



17 

 3 



— 0.55 

 + 1.59 



17 

 3 



— 1.46 

 + 0.37 



— 1.23 



10 

 18 

 11 



— 1.28 



— 0.67 



— 0.34 



10 

 20 

 11 



Average for 1849 .... 



— 0.74 



20 



— 0.23 



20 



— 0.55 



39 



— 0.73 



41 



* Used with a weight of 20. 



