ON THE FORMATION OF NEBULAE. 339 



0J5T THE FOKMATION OF NEBULAE. 



Br WILLIAM M. DAVIS, Esq. 



HpHE close proximity of the satellites of Mars to their primary has 

 -*- led me to investigate the lesson taught by them and other satel- 

 lites of short periods. 



This investigation has enabled me to demonstrate : 



I. That the nebular hypothesis fails to account for the present con- 

 dition of the solar system, without the additional hypothesis of a resist' 

 ing medium in space. 



II. It has enabled me to show, also, that, although this medium 

 tends to bring the solar and all other systems to a state of quiescence, 

 it has no such tendency on the material "universe as a whole, provided 

 that the ponderable matter thereof be of infinite extent. If, however, 

 the ponderable matter as distinguished from the ether be of finite 

 extent, it should come to rest, as will be shown in the sequel. 



The first proposition will be established by taking the first satellite of 

 Mars as an example, and proving that it must have been at least fifteen 

 or twenty times as far as it now is from its primary when it was able to 

 take on the globular form from the nebulous ring out of which it was 

 made. This being established, it follows, as a necessity, that its orbit 

 must have contracted into its present dimensions since it was thus 

 formed ; and the satellite during this time has condensed into its present 

 condition. 



As the same cause which contracts the orbits of the satellites should 

 produce a like result upon those of the planets, it follows that they, too, 

 must have been farther away from the centre of the system than they 

 now are, when they took on the globular form from their nebulous rings. 



The hypothesis of a resisting medium has been adopted to account 

 for this contraction of orbits, as no other hypothesis seems competent 

 to do so. 



That this satellite of Mars and others in our sj T stem were much 

 farther away from their primaries than they now are, will be proved, 

 by proving that, if a nebulous satellite revolved around any primary 

 in the short period in which most of the solid ones now do, the tidal 

 energy or tendency to elongation and disruption which would, in 

 that case, be generated on its opposite sides by such rapid revolution, 

 would be sufficient to tear it into atoms. These atoms would be dis- 

 tributed around the primary in the form of a nebulous ring, which ring 

 would be in a state of stable equilibrium, and therefore could not be 

 reconverted into the globular form. 



Permit me, then, to bring forward some imaginary experiments, for 

 the purpose of illustrating certain dynamical principles (and methods) 

 to be employed in proving the fact just stated. 



