MODEEN IDEAS ON THE END OP THE WORLD JAUMANN. 219 



on the extreme wing, but by virtue of it we now have exact notions 

 regarding the manner of propagation of gravitation through the cos- 

 mic ether. The anomalies of the field of gravitation compensate each 

 other in cosmic space, according to a law analogous to that which rules 

 the irregularities of the distribution of temperature in a good con- 

 ductor of heat. It is only for stars in a state of repose that the New- 

 tonian law of effects at a distance follows exactly from the differential 

 law of gravitation. 



Now, the motions of the planets produce disturbances, a kind of 

 damming up, so to speak, of the field of gravitation in front of the 

 moving stars, giving birth to new forces of gravitation added to the 

 Newtonian forces. Although very small, it can be determined with 

 precision that the most important among them has the same direction 

 as that of the motion of the planet to which it is a stimulus. It in- 

 creases with the speed of the planet and varies in inverse ratio to the 

 distance separating it from the sun. These new forces of gravitation 

 introduce into the planetary movements disturbances which can be 

 calculated without difficult}?^, and even cause the deviations from the 

 Newtonian law which we have mentioned above. By them are ex- 

 plained the anomalous perihelic rotations, accelerations, oscillations 

 of the vertical, etc. — that is, all the phenomena of gravitation, without 

 any being left over, which the Newtonian law of effects at a distance 

 was incapable of doing. These new forces of gravitation moreover 

 give to the planetary system a physical stability of unlimited dura- 

 tion. They keep the planetary orbits in their present form, not 

 only in spite of the very considerable resistance due to friction of the 

 cosmic ether, but also in spite of enormous accidental disturbances. 

 If a disturbance of this nature (which might be due, for example, to 

 the passage in the neighborhood of the solar system of a fixed star 

 imbued with a very rapid motion of its own) should be produced, and 

 modify entirely the form of the planetary orbits, the new forces of 

 gravitation would introduce into the elements of the orbits such vari- 

 ations that these planetary orbits would gradually return exactly to 

 their existing stable form. Far from becoming dangerous, the fric- 

 tional resistance of the cosmic ether, on the contrary, helps essentially 

 to make the planetary orbits stable. The greater this resistance the 

 more considerable become the new forces of gravitation and the more 

 obstinate the planetary orbits in conserving, in spite of all the disturb- 

 ances, their stable form. Thus there can no longer be any question of 

 the planets dropping into the sun. Far from being unstable, far from 

 tending toward a destruction more or less remote, the planetary sys- 

 tem is, then, established for a duration which, estimated according 

 to the ideas of time that we are able to conceive, may be considered 

 as eternal. 



