1883.] ^6J [Chase. 



relative elasticity which is much greater than that of air, and which must, 

 therefore, be peculiarly subject to harmonic oscillations; the waves of 

 light, like auroral flashes, which have often been seen in the tails, point 

 to electric, phosphorescent, and luminous rhythms; the frequent inter- 

 changes between the tail and the nucleus, as well as the rupturing ex- 

 plosions and the formation of nucleoli, must be subject to the laws of 

 phyllotactic and gravitating rhythm; if the aether is material, it must be 

 influenced by rotational and orbital tendencies, even if its elasticity is so 

 great as to prevent actual orbital motion, and hence the "actinic shadows" 

 may be curved. 



308. Other Cometary Considerations. 

 Phyllotactic distribution in organic growth, in frost tracery and other 

 forms of crystallization, and in satellite or planetary groupings, points to 

 a continuance of tendency, over periods which are proportional to the 

 resistance interposed by the inertia of the particles or masses which 

 partake of the distribution. When the inertia is very small, as in the 

 sethereal interferences to which spectral lines are attributed, the adapta- 

 tion to requirements of "extreme and mean ratio" may be nearly or 

 quite instantaneous. We may, therefore, reasonably look for evidences of 

 adaptation, such as are shown in Notes 295, 302 and 305, as Avell as for 

 various modifications by other forms or kinds of harmonic tendency. 

 Refraction of energy (Note 286), and Draper's "latent light," may also 

 contribute to the curvature of tails, in a medium which is perhaps more 

 tenuous than the "fourth form of matter," and which imparts sympathetic 

 vibrations to the adjacent aether. 



309. Effects of Cometary Eccentricity. 

 The tendencies to sethereal rotation and revolution about stellar centres 

 may, perhaps, be so adjusted to other oscillatory tendencies as to oppose 

 little or no resistance to planetary motions in orbits of small eccentricity. 

 Most of the cometary orbits, however, are so eccentric that their nis viva, 

 at every stage of their journey, is nearly twice as great as it would be if 

 their paths were circular. Such amount of living force is more than 

 sufflcient, whenever there is any appreciable resistance, to produce and 

 maintain luminous and thermal phenomena, of the same kind as occur in 

 the explosive combinations of gases. The orbital energy may be resolved 

 into two rectangular components, one of which passes through the sun, 

 while the other is tangential to the path of the revolving tether. The 

 latter may adapt itself so readily to the fethereal vortices as to make no 

 disturbance; the former being perpendicular to the sethereal track, must 

 encounter a continual resistance and retardation, unless it is compensated 

 by luminous, electric, gravitating, or other kinetic undulations. 



310. Eccentricity at Mean Centre of Inertia. 

 The fundamental identity (Note 280) represents a uniform velocity, and 

 we may, therefore, look for evidences of primitive photodynamic influence 



