338 ANNUAL EEPORT _SMITHSONIAN INSTITUTION, 1908. 



the spots in most ca^es have almost exactly the same relative separa- 

 tions as have the corresponding lines when observed in the laboratory 

 in a magnetic field; (5) that lines found double in spots near the 

 sun's limb are also found double when observed in the laboratory at 

 right angles to a magnetic field; (6) that, as shown by Kowland, 

 electric charges in revolution produce a magnetic field; (7) that, as 

 shown by Thomson, it is probable that electrically charged bodies 

 or ions are numerous in the sun; (8) that the spectroheliograph has 

 shown immense spiral configurations suggesting vortices in the 

 higher solar layers and that these vortices are unmistakably con- 

 nected with sun spots; (9) that .the vortices are some right handed 

 and others left handed; (10) that in sun spots surrounded by right- 

 handed vortices the polarization of the components of the spec- 

 trum doublets is always found opposite to that for sun spots with 

 left-handed vortices. In view of all this it must be admitted that 

 the existence of magnetic fields in the neighborhood of sun spots is 

 beyond reasonable question, and Mr, Hale's explanations of them as 

 due to the revolution of electrical charges in vortices have strong 

 support. At the same time it must be kept in mind that the vortical 

 motions are inferred rather than demonstrated, and inferred only for 

 high levels, presumably above the levels of sun spots. Furthermore, 

 spectra of spots near the sun's limb do not reveal evidence of motion 

 such as would be expected if vortices exist in the spots themselves. 

 Further evidence must therefore be awaited before fully accepting 

 the vortex theory of the production of the magnetic fields which Mr. 

 Hale has discovered. 



A possible application to terrestrial affairs of this new discovery 

 of magnetism in sun spots springs at once into mind, but according 

 to Mr. Hale's view the evidence at present is opposed to the con- 

 clusion that the magnetic fields found in sun spots can produce ap- 

 preciable effects on the earth. Nevertheless, it will be almost a matter 

 of regret if further study shall not indicate that the magnetic sun- 

 spot fields are competent to produce the disturbances of terrestrial 

 magnetism which for many years have been known to be intimately 

 related to the prevalence of sun spots. 



