6 fi ~ n 



Declination 



Sifia 



y-"' 5ummtr 

 WM»r ■ 



Dip 



fa 



24 



Horiionfal Inhnsitt/ 



(b) (c) 



Fig. 8-40. Diurnal variation curves (a) for D, (b) for H, (c) for I (after Hazard). 



368 



