DISSOLUTION. 541 



sistance of the ethereal medium. From ethereal resistance 

 is inferred a retardation of all moving bodies in the Solar 

 System a retardation which certain astronomers contend 

 even now shows its effects in the relative nearness to one 

 another of the orbits of the older planets. If, then, retarda- 

 tion is going on, there must come a time, no matter how 

 remote, when the slowly diminishing orbit of the Earth will 

 end in the Sun; and though the quantity of molar motion 

 to be then transformed into molecular motion, will not be 

 so great as that which the calculation of Helmholtz supposes, 

 it will be great enough to reduce the substance of the Earth 

 to a gaseous state. 



This dissolution of the Earth, and, at intervals, of every 

 other planet, is not, however, a dissolution of the Solar 

 System. Viewed in their ensemble, all the changes ex- 

 hibited throughout the Solar System, are incidents accom- 

 panying the integration of the entire matter composing it: 

 the local integration of which each planet is the scene, 

 completing itself long before the general integration is 

 complete. But each secondary mass having gone through 

 its evolution and reached a state of equilibrium among its 

 parts, thereafter continues in its extinct state, until by the 

 still progressing general integration it is brought into the 

 central mass. And though each such union of a secondary 

 mass with the central mass, implying transformation of 

 molar motion into molecular motion, causes partial dif- 

 fusion of the total mass formed, and adds to the quantity of 

 motion that has to be dispersed in the shape of light and 

 heat; yet it does but postpone the period at which the total 

 mass must become completely integrated, and its excess of 

 contained motion radiated into space. 



* 182. Here we come to the question raised at the 

 close of the last chapter does Evolution as a whole, like 



* Though this chapter is new, this section, and the one following it, are 

 not new. Jn the first edition they were included in the final section of the 



