182 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 42 



Figure 2.— Charts showing secular change of geomagnetism. Upper, compass 

 direction or declination at six stations ; center, lines of zero magnetic declina- 

 tion or agonies with dots on side of agonic on which declinations are easterly; 

 lower, lines of zero magnetic inclination or isoclinics. 



