32 



from below, appear to whirl in opposite direc- 

 tions. But this hypothesis is still under investi- 

 gation. Stormer of Chnstiania has developed for 

 us the mathematical theory of the motions in the 

 solar atmosphere of vapors within the influence of 

 such magnetic fields, with results of great interest. 



FIG. 25. Two Bipolar Sun-spot Groups. 



The illustration (Fig. 25) shows that the hydrogen 

 flocculi about a bipolar spot-group resemble the 

 lines of force between two magnets of opposite 

 polarity (Fig. 24). But similar structure might be 

 produced by the direct hydrodynamical influence 

 of the spot vortices upon the solar atmosphere 



