Mr. J. Gill on the Dynamical Theory of Heat. 375 



most distant planet of the system), till, arrived at the limits where 

 the repulsive force and the power of gravitation are in equili- 

 brium, the outflowing current should come quietly to a state of 

 rest on the vague shores of the solar aerial ocean in circumam- 

 bient space. Here the solar atoms would have no motion, except 

 perhaps some slight vibratory movement from the almost ex- 

 hausted undulations of the sether in these distant regions of 

 space ; but gravitation would soon again begin to predominate, 

 and each atom, like a pendulum in vibration, would begin gra- 

 dually to return towards its centre of gravitation in the sun. 

 While thus on the verge between their outward and inward 

 movements, the atoms would be in a state of almost perfect 

 equilibrium or neutrality of general forces ; and the meeting of 

 the returning ripples with the spent waves still moving slowly 

 on, under the expiring influence of outward repulsion, might 

 induce an approach of the atoms sufficient to cause aggregation, 

 from the effect of mutual attraction in the absence or abeyance 

 of other forces. 



We nowhere perceive homogeneity in nature ; and even the 

 distribution of highly rarefied gaseous matter in space cannot be 

 supposed to be effected with strict geometrical symmetry. The 

 slightest inequalities of distance between the atoms hovering on 

 their boundaries of solar gravitation would form centres of ag- 

 gregation under the influence of mutual atomic attraction, which 

 would become the nuclei of meteoric formations. In the agglo- 

 merated masses some incipient heat would be generated in the 

 act of aggregation, by converting the motion of translation with 

 which the particles approached each other into reciprocating or 

 orbital molecular motion; but the general temperature would 

 probably be low, and the newly formed meteoric masses might 

 be of considerable density. 



The return of the meteoric matter, in the shape of these newly 

 formed or still forming masses, to its central source in the sun 

 presents an interesting subject of speculation. Whatever ideas 

 may be entertained of the interstellar sether as a resisting medium, 

 it seems certain that the meteorites falling towards the sua would 

 meet with considerable resistance from the outflowing tide of the 

 solar atmosphere. Many years ago a theory of the sun's dyna- 

 mical action appeared which was perhaps entitled to more atten- 

 tion than it received. It supposed that the centrifugal action 

 of the sun's rotation on his axis causes his equatorial rays to 

 issue obliquely in the direction of the motion of the planets, 

 and thus to influence the planetary motions by direct dynamical 

 action. The meteorites in their approach towards the sun would 

 be deflected from a direct radial course by the slanting direction 

 of the issuing lines of the solar current, and would thus be 



