above them, and it is still a question whether this 

 or the electromagnetic influence is predominant. 

 The existence of electric vortices in sun-spots is 

 indirectly shown by the presence of the magnetic 

 fields, which presumably could not be produced in 

 the sun by any other means. But direct proof of 

 the existence of these vortices was subsequently 



Preliunc Elevation 



MjKj 



00 iVOD 



e'cc ly-invcrs-on f * 



JOOO 

 QS 

 10 800 



i7 



Z50 



JfPb.La 

 *- re,8a, 



Nb 



FIG. 26. Inflow at High Levels and Outflow at Low Levels above Spots 



found by Evershed, of Kodaikanal, who measured 

 the outflow of gases close to the solar surface and 

 their inflow at higher levels. This work has been 

 repeated and extended on Mount Wilson with 

 highly significant results, affording not only an 

 accurate picture of the conditions existing above 

 a sun-spot, but also the means of assigning to each 

 line of the solar spectrum a definite level in the 

 sun's atmosphere. 



