A NEW THEORY OF THE SUN. 227 



serve through a strong pane of glass inserted in the side of the boiler 

 near the liquid surface, lit up by an incandescent electric lamp within ? 

 The loss of heat by radiation from the boiler would give rise to con- 

 vection-currents, and partial condensation of the vapor atmosphere ; 

 then, if the motion of the water were made visible by means of coloring 

 matter, we should observe convection-currents in the fluid mass sepa- 

 rate and distinct from those in the gaseous mass ; but these convection- 

 currents would cause no visible disturbance of the liquid surface, which 

 would present itself to the eye with the smoothness of a mirror. It is 

 only in the event of the steam-pressure being suddenly relieved at any 

 point on the surface that a portion of the water would flash into steam, 

 causing a violent upheaval of the liquid. 



The dark spots on the sun appear to indicate commotion of this 

 description, but these are evidently not the result of mere convection- 

 currents ; if they were, they would occur indiscriminately over the 

 entire surface of the sun, whereas telescopic observation has revealed 

 the fact that they do occur almost exclusively in two belts, between 

 the equator and the polar surfaces on either side. Their occurrence 

 could be satisfactorily explained if we could suppose the existence of 

 strong lateral currents flowing from the polar surfaces toward the 

 equator, which lateral currents in the solar atmosphere would cause 

 cyclones or vortex action with a lower and denser atmosphere consist- 

 ing probably of metallic vapors ; this vortex action extending down- 

 ward would relieve the fluid ocean locally from pressure, and give rise 

 to explosive outbursts of enormous magnitude, projecting the lower 

 atmosphere high above the photosphere, with a velocity measured, 

 according to Lockyer, by a thousand miles a second. It will be seen 

 from what follows how, according to my views, such vortex action 

 in those intermediate regions of the sun would necessarily be pro- 

 duced. 



But supposing that, notwithstanding the difficulties just pointed 

 out, convection-currrents sufficed to effect a transfer of internal heat 

 to the surface with sufficient rapidity to account for the enormous 

 surf ace-loss by radiation, we should only have the poor satisfaction of 

 knowing that the available store would last longer than might have 

 been expected, whereas a complete solution of the problem would be 

 furnished by a theory, according to which the radiant energy which is 

 now supposed to be dissipated into space and irrecoverably lost to our 

 solar system, could be arrested and brought back in another form to 

 the sun himself, there to continue the work of solar radiation. 



Some six years ago the thought occurred to me that such a solution 

 of the solar problem might not lie beyond the bounds of possibility, 

 and, although I can not claim intimate acquaintance with the intrica- 

 cies of solar physics, I have watched its progress, and have engaged 

 also in some physical experiments bearing upon the question, all of 

 which have served> to strengthen my confidence, and to ripen in me 



