100 G. F. Becker — Kant as a Natural Philosopher. 



ished with increasing radius to a minimum, and increased again 

 towards the edge. Nebulous material was driven from the 

 center towards the periphery in the equatorial plane of the 

 vortex and flowed back again along the axis of rotation. The 

 first stage in the evolution of systems was the segregation of 

 opaque matter in spots, such as are still to be seen on the sun. 

 In the smaller subordinate vortices these accumulated until 

 they formed a crust which partially or completely arrested the 

 vertical circulation. The minor stellar bodies so consolidated 

 were then captured by the larger vortices and were incorporated 

 into them as passive constituents. These opaque masses sought 

 a position of equilibrium in the rotating fluid of the vortex. 

 At first such a body would descend towards the center. If, 

 however, it possessed sufficient "solidity," which seems to be 

 mass per unit of exterior surface,* it soon acquired such centri- 

 fugal velocity as to be thrown out of the periphery of the vor- 

 tex, passing into the next similar vortex and so on. It thus 

 became a comet. If the opaque mass had less solidity, it 

 found a position of equilibrium within the vortex and became 

 a planet moving on an orbit of small eccentricity. f The 

 planets of smallest solidity are nearest the sun.J 



Swedenborg also published a vortical cosmogony in 1734, 

 forty-seven years after the appearance of Newton's Principia. 

 Messrs. M. JNyren§ and E. S. Holdenf have each given some 



* Cf. part 3, sec. 122. Descartes regarded space as a "plenum" and does not 

 here consider motion in a vacuum. The measure of force was solidity into 

 velocity. The resistance of the plenum was proportional to the exterior surface 

 of a moving mass. 



f Et parceque toutes les petites parties de la matiere qui compose un tourbillon 

 ne sont pas egales ni en agitation, ni en grandeur, et que leur mouvement est plus 

 lent selon qu'elles sont plus eloigoees de la circonference, jusques a un certain 

 endroit au-dessous duquel elles se meuvent plus vite, et sont plus petites selon 

 qu'elles sont plus proches du centre, ainsi qu'il a ete dit ci-dessus, si cet astre est 

 si solide que, devant que d'etre descendu jusques a l'eudroit ou sont les parties du 

 tourbillon que se meuvent le plus lentement de toutes, il ait acquis autant d'agita- 

 tion qu'en out celles entre lesquelles il se trouvera. il ne descendra point plus bas 

 vers le centre de ce tourbillon, mais, au contraire il montera vers sa circonfereuce. 

 puis passera de la dans un autre, et ainsi sera change en une comete. Au lieu 

 que s'il n'est pas assez solide pour acquerir tant d'agitation, et que pour ce sujet 

 il descende plus bas que I 'endroit ou les parties du tourbillon se meuvent le moins 

 vite, il arrivera jusques a quelque autre endroit eutre celui-ci et le centre, ouetant 

 parvenu il ne fera plus que suivre le cours de la matiere qui tourne autour de ce 

 centre, sans monter ni descendre davaotage, et alors il sera change en une planete. 

 Part 3, sec. 119. 



\ Therefore the earth must be less dense than Mars, which has the smaller 

 diameter (part 3, sec 14*7), and therefore the earth must consist of a rigid shell 

 with a fiery interior (part 4, sec 3), Descartes concludes. This is the first asser- 

 tion that the earth has a fluid interior. Descartes was driven to make it by the 

 exigencies of a false theory. The doctrine once accepted, its origin was forgotten; 

 and but for Lord Kelvin, it would probably have remained a misleading article of 

 faith with geologists to the eud of the 19th century. 



§ Vierteljahrsschrift der astronomischen Gesellschaft. 1879, p. 80. This paper 

 is translated in the New Church Review, July. 1897. 



\ North American Review, vol. cxxxi, 1880, p. 377. 



