APPLICATION TO BINARY STARS. 157 



under consideration has suffered fission by evolution along this line of figures, 

 as is assumed, then the former alternative is eliminated. It does not seem 

 that the tidal factor can tend toward stabiUty. This intuition is strongly 

 supported by the results obtained by Darwin, loc. cit., attacking the problem 

 from the other end, viz., that it is not possible to bring two homogeneous 

 fluid masses near enough to touch without their being certainly in unstable 

 equilibrium. 



We observe next that the binary stars are now actual stars of consider- 

 able density. Consequently if they have originated from the fission of neb- 

 ulas they have undergone enormous contraction. The contraction implies 

 increased rotation which would increase the already dangerous tendency 

 for at least one part to suffer further fission. Tidal friction would offset 

 this tendency by decreasing the rotations, but considering all the factors 

 involved, it is seen that if a fluid mass ever gets to the state where fission 

 occurs, there is at least great danger of its breaking into many pieces. 



Consequently we are led to believe that if binaries and multiple stars 

 of several members have developed from nebulas, the nebulas must orig- 

 inally have had well-defined nuclei. The photographs of many nebulas 

 support this conclusion. But we observe that if we are forced to this 

 position we do not explain anything — we only push by an assumption 

 the problem of explaining the binary systems a little farther back into 

 the unknown. 



