IN THE SOLAR SYSTEM. 



77 



we arc;, therefore, led to the conclusions, that from the equatorial zone there is a perma- 

 nent ascending current of ether, and that upon the two polar regions there are descending 

 currents. 



If the sun's surface had a uniform temperature, its axial rotation should bring about 

 the same conditions as those I have shown to result from the peculiar distribution of its 

 heat. The fluid resting upon the revolving sphere, its lowest stratum should partake ot 

 the motion of the sphere. The centrifugal force resulting from the circular motion should 

 cause an accumulation of fluid upon the equatorial zone, and as a result a rarefied condi- 

 tion of the fluid in those parts where the causes of the excess existed in the smallest de- 

 gree. The centrifugal force is null at the poles ; therefore, upon the polar regions should 

 be thrown the supply of cold fluid to preserve the equilibrium. 



As particles of fluid moving from opposite points towards a centre, always take the 

 direction of a circle round that centre, we arc led to the; belief that the ether descends upon 

 the polar regions in the form of vortices. 



Thus do we find in the constitution of the sun, two distinct causes, the one depending 

 on heat the other on motion, which produce in the ethereal medium a double circulation 

 over the solar surface, and through the region of the planets. 



Let us trace the course of these stupendous currents. Towards the poles of the sun, 

 as the seats of the lowest heat and the least motion, the ether is drawn from the regions 

 of space, and descends upon the poles and the adjacent parts in the vortical form. Thence 

 it is wafted by the double set of causes towards the equator, whence it is forced out into 

 the region of the planets, in a mass whose form closely resembles a perfectly flat plate, the 

 plane of which nearly coincides with that of the sun's equator. 



With regard to the energy with which these movements in the ether are effected, our 

 approaches to a conjecture must be based upon a comparison between the causes which 

 produce currents in the earth's atmosphere, and those brought into play in the grand 

 ethereal circulation. 



In carrying out this parallel, we must fix our attention successively upon each of the 

 causes known to be concerned in the production of motion in the terrestrial atmosphere, 

 and then upon the corresponding one, believed to influence the movement of the ether. 



By collating the results of these several comparisons, we may obtain the basis for a con- 

 jecture as to the velocity, of the ethereal currents. 



The immediate cause of all motion in our atmosphere is the earth's gravitating power, 

 and by an analogous influence the sun occasions the ethereal circulation. The sun's 

 energy in this respect is eastern paribus directly as its mass. The mass of the sun is 354,936* 

 times that of the earth. Here we have the first element of our comparison. 



* Herschel. 



