8 POPULAR 8CIE2JCE MONTHLY. 



observations that it described an orbit seemingly circular, having a 

 radius of about 1". There could be no doubt that this motion 

 must be due to the revolution of a satellite, but the latter long evaded 

 discovery, though carefully searched for with the new telescopes which 

 were from time to time brought into use. At length in 1895 Sehaeberle 

 found the long-looked-for object with the 36-inch telescope of the 

 Lick Observatory. It was nearly in the direction predicted by Auwers, 

 and a year's observation by Sehaeberle, Barnard and others showed 

 that it was revolving in accordance with the theory. 



If the conclusion of Auwers that the apparent orbit of the principal 

 star is circular were correct, the distance of the satellite should always 

 be the same. It would then be equally easy to see at all times. The 

 fact that neither Burnham nor Barnard ever succeeded in seeing the 



!835j 



Fig. 2. x:\ 



it .' \ / 



<= . X jl 1869 



Fig. -. Apparent Orbit of oc Centauri, i:y Professob See. 



object with the Lick telescope would then be difficult to account for. 

 The fact is, however, that the periodic motion of Procyon is so small 

 that a considerable eccentricity mighl exisl without being detected by 

 observations. The probability is, therefore, that the apparent orbit is 

 markedly eccentric and i lint the satellite was nearer the primary dur- 

 ing the years 1878-92 than it was when discovered. 



One very curious feature, common to both of these systems, is that 

 the mass of each satellite, as compared with I hat of its primary, is out 

 of all proportion to its brightness. The remarkable conclusions to be 

 drawn from this fact will he discussed in a subsequent chapter. 



