Smithsonian Report, 1913. — Bauer. 



Plate 6. 



Fig. 1.— Curves Showing the Secular Change in the Magnetic Declination and 

 IN THE Dip at London, Boston, and Baltimore. 



[Drawn for supposed length of freely suspended magnetic needle of about 50 

 centimeters, or nearly 20 inches.] 



Fig. 2.— Map of Region about the Magnetic North Pole, Indicating how the 



Compass Points in the Vicinity. 

 [The earth's magnetic poles are, on theaverage, 1,1^00 miles distant from the geographical poles.] 



