110 



NEW MEASUEEMENTS OF DISTANCE OF ^UN. 



ately rejected when one finds that some of the most ener*jetic partici- 

 pants were precisely those observatories that had their hands most full 

 with the astrographic chart (fig. 1). By a cruel stroke of fate Sir 

 David Gill at the Cape was compelled to remain a spectator of the 

 work, for the j^lanet came so far north that it was practically unob- 

 servable in the Southern Hemisphere, while in England we had the 

 unique spectacle of a j^lanet north of the zenith. 



Figure 2, borrowed from Professor Wilson's articles in Popular 

 Astronomy, shows very clearly the circumstances. Correspondijig 



ORBIT 



ORB^^.,--"" 



Fig. 2.— Relative positions ol' Eros inid Earth troui Oct. 1, 1900, to Feb. 2,S, 1901. 



positions of the earth and the planet are joined, and if we follow out 

 in imagination the directions that these lines must haA'e, remembering 

 that the orbit of the planet is inclined 10° to that of the earth, we 

 see that the planet described a loop at opposition, as all exterior 

 planets do, but that the loop was of very unusual })ropt)rtions 



To discuss in any detail the circumstances of the apparition and 

 the way in which they can be utilized for a determination of the 

 parallax would take too long. But we may get a good idea of a 



