PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 659 



•to others, which sideward motion combined with gravitation 

 toward centers of attraction, necessarily will originate rotary 

 motions, which again combined with the force of inertia changes 

 the globular nebul?e. into spheroids, showing that the simple force 

 of gravitation is sufficient to explain the origin of the planetary 

 motions. 



Plateau invented the beautiful experiment of an oil globe bal- 

 anced in the middle of a mass of alchohol and water, so mixed as 

 to have the same specific gravity; this globe is made to revolve 

 by means of an axis and disk in its centre, it then flattens in the 

 direction of its axis, expands toward its equator, and finally 

 throws off a ring, which, by increasing velocity of its revolution, 

 breaks up in smaller globes, all revolving around the primitive 

 axis and each rotating in an opposite direction on an axis of its 

 own. As the results of this experiment are of so short a duration 

 that it is impossible for a large audience to observe the important 

 details, I have truthful diagrams made and exhibited here, show- 

 ing the resultant changes. 



This experiment was supposed to illustrate sorne details of the 

 nebular theory of La Place, namely, the formation of fluid rings 

 from nebular matter, and then breaking up into planets and sate- 

 lites; but it has done much injury by preventing the right under- 

 standing of the cosmogony of the universe. It has, namely, 

 caused the impression that rings were thrown ofl' from the 

 revolving centre, as is the case in this experiment; that the planets 

 were formed by rings thrown off from the sun, the satelites being 

 rings thrown off by the planets, and Saturn was pointed out as an 

 illustration of a planet which had thrown ofl" a ring in the same 

 way as the oil ring, in Plateau's experiment, which ring was not 

 yet broken up into fragments or moons. 



Now the impression that rings, moons or planets can possibly 

 be thrown out from a central revolving body, is erroneous, because 

 the supposed similarity between the results of Plateau's experi- 

 ment and the formations of planetary systems after the nebular 

 theory does not exist. In Plateau's experiment we start with a 

 large fluid ball, held together by nothing but a slight cohesion ; 

 this globe is disrupted from the inside 'by the centrifugal force 

 developed by the rotation of a central solid ball or disk; in the 

 universe we have nebular matter diflused into space, and mutually 

 acting and acted upon by the universal force of gravitation: the 

 reaction produced by this force, commencing from the outside and 



