Mechanical Illustrations of the Planetary Motions. 335 



panying the magnet ; and, if so turned before the introduc- 

 tion of the magnet, the magnet will bring the ring into a 



concentric position, permitting its introduction into it, while 

 a non-magnetic bar cannot be so introduced. The magnet, 

 instead of causing collision, prevents it.* 



I have thus, both by theory and by experiment, attempted to 

 explain that phenomenon, hitherto, as I think, not accounted 

 for in any satisfactory manner, and to show that it rests on 

 the same principle as the standing of a spinning-top, the pre- 

 cession of the equinoxes, the retrogradation of the moon's 

 nodes, and the perturbation of the planes of the orbits of 

 the planets. How far I have succeeded I leave others to 

 decide. 



* The loose structure, or fluidity, of Saturn's ring will not affect my theory, 

 so long as there is sufficient cohesion, or mutual attraction, among its component 

 particles, to keep them together as one hody, and sufficient velocity of rotation 

 to preserve the annular form. 



z2 



