Prof. P. E. Chase on ^Ethereal Nodes. 203 



ing. The magnetic moment, then, was sensibly zero. I then 

 slid the coil along its railway, and, by aid of a small needle 

 very strongly hardened, and rendered sensibly astatic by a 

 compensating bar, ascertained the existence of energetic oppo- 

 site polarities at the very extremity of the bar and a little 

 nearer its middle. This delicate but absolutely conclusive ex- 

 periment, thanks to the regularity and symmetry of the results 

 obtained, cannot leave any doubt of the legitimacy of the in- 

 duction which guided us in this portion of our investigation. 



In brief, these last experiments seem to make it evident that 

 there exists between the temporary and the permanent mag- 

 netization a sort of independence more decided than had 

 hitherto been admitted. I persist in thinking that it must be 

 attributed, at least in part, to a difference of origin, resulting 

 from a real magnetic heterogeneity in the steel *. 



XXVII. On the Nebular Hypothesis. — V. ^Ethereal Nodes. 

 By Puny Earle Chase, LL.JD., S.P.A.S., Professor of 

 Philosophy in Haverford College. 



[Continued from vol. ii. p. 202.] 



ONE of the most important corollaries of the theory of uni- 

 versal gravitation is tersely stated by Stockwellf as 

 follows: — " The amount by which the elements of any planet 

 may ultimately deviate from their mean values can only be 

 determined by the simultaneous integration of the differential 

 equations of those elements, which is equivalent to the sum- 

 mation of all the infinitesimal variations arising from the dis- 

 turbing forces of all the planets of the system during the lapse 

 of an infinite period of time." Therefore, within the limits of 

 secular eccentricity, the result is the same as if the nebular 

 hypothesis were true. 



There should, then, be tendencies, in the neighbourhood of 

 every inert particle which floats in an elastic medium, to the 

 formation of harmonic nodes of various kinds ; and the sum of 

 such tendencies should fix loci of cosmical aggregation before 

 there had been any considerable shapings of definite mass. 

 The subsequent values of relative mass would depend upon 

 mutual conditions of equilibrium between various forms of 

 living force. But such accordances as would be thus produced, 

 however interesting and however striking they might be 

 deemed, would furnish no more conclusive evidence of the 

 nebular theory, as popularly interpreted, than of the Cartesian 



* See Annates de VEcole Normale Superieure, t. iii. p. 52. 

 t Smithsonian Contributions, 232. viii. 



