Smithsonian Report, 1913. — Hale. 



Plate 8. 



Fig. 13.— Head of the 75-Foot Spectograph of the 150-Foot Tower 



Telescope. 



s. 90°. 



Equator. 



N. 90°. 



Fig. 14.— The Curve Represents the Theoretical Variation of the Dis- 

 placements OF Spectrum Lines with the Heliographic Latitude. 



The sun is assumed to be a magnetic sphere with its magnetic poles coinciding with tlie 

 poles of rotation. The points represent mean values of the observed displacements. 

 "Vertical scale: 1 square = 0.001 mm. = 0.0002 Angstrom. 



