THE EARTH AND SUN AS MAGNETS 



119 



Fig. 13. 150-foot Toweb Telescope. 



as to the proportion at different levels of positive and negative elec- 

 trons, and of the perturbations due to currents in the solar atmosphere, 

 must delay the most effective application of these methods, though they 

 promise much future knowledge of the magnetic field at high levels in 

 the solar atmosphere. 



Of the field at low levels, however, they may tell us little or nothing, 

 for the distribution of the electrons may easily be such as to give rise 

 to a field caused by the rotation of the solar atmosphere, which may 

 oppose in sign the field due to the rotation of the body of the sun. 

 To detect this latter field, the magnetic field of the sun as distinguished 

 from that of the sun's atmosphere, we must resort to the method 

 emploA'ed in the case of sun-spots — the study of the Zeeman effect. If 



