122 KANT'S UNIVERSAL NATURAL HISTORY 



serve in some measure to establish a general remark con- 

 cerning the Theory of the Heavens. Jupiter by exact 

 calculation has at its equator a ratio of the gravity to the 

 centrifugal force of at least 9^:1; and, if its mass were 

 of uniform density throughout, it ought, according to the 

 principles of Newton, to show a still greater difference 

 than Jth between its axis and its equatorial diameter. 

 But Cassini has found it to be only T V and Pound T \, 

 sometimes T \ ; and at least all their different observations 

 which by their difference establish the difficulty of this 

 calculation agree in making it much less than it should 

 be according to Newton's system, or Tather according to 

 his hypothesis of uniform density. And hence, if the 

 hypothesis of uniform density which occasions such a great 

 deviation of the theory from observation is changed into 

 the much more probable view, in which the density of 

 the mass of a planet is represented as increasing towards 

 its centre, then we shall not only justify the observations 

 on Jupiter, but even in the case of Saturn, a planet 

 much more difficult to gauge, we shall be able distinctly 

 to understand the cause of a less flattening of its spheroidal 

 body. 



From the mode of the formation of Saturn's ring we 

 have found occasion to hazard the bold step of deter- 

 mining by calculation the time of its axial rotation, 

 which the telescopes are not able to discover. Let us 

 increase the example given of a physical prediction by 

 the addition of another in reference to the same planet, 

 which also will have to wait for the evidence of its correct- 

 ness from the more perfect instruments of future times. 



According to the supposition that Saturn's ring is an 

 accumulation of the particles which, after they had 



