ON THE SUN'S HEAT. 



383 



be done for every one of our pyramidal rods, with, 

 however, in the first place, thin partitions of matter 

 impervious to heat separating every pit from its 

 four surrounding neighbours. Precisely the same 

 series of events as we have been considering will 

 take place in every one of the pits. 



Suppose the whole complex mass to be rotating 

 at the rate of once round in twenty-five days, which 

 is, about as exactly as we know it, the time of 

 the sun's rotation about its axis. 



Now at the instant when the paddle stops let 

 all the partitions be annulled, so that there shall be 

 perfect freedom for currents to flow unresisted in any 

 direction, except so far as resisted by the viscosity 

 of the fluid, and leave the piece of matter, which 

 we may now call the Sun, to himself. He will 

 immediately begin showing all the phenomena 

 known in solar physics. Of course the observer 

 might have to wait a few years for sunspots, and 

 a few quarter-centuries to discover periods of sun- 

 spots, but they would, I think I may say probably, 

 all be there just as they are, because I think we may 

 feel that it is most probable that all these actions 



