The entire area outside of the heavy solid line may be called the "Zone 

 of Approach by Ship"; the area within it the "Zone of Man-and-Dog 

 Travel." The stippled portion of the latter is the "Zone of Comparative 

 Inaccessibility." The distance between the isochronic lines is five days 

 dog-sledge travel, or 60 miles. Incidentally the map shows the superiority 

 of Peary's position of 1908 over all others on land as a base for a dash 

 aimed at the point of latitude 90° N. It is also favorably situated for an 

 attack on the "Pole of Inaccessibility," which is only 200 miles farther away 

 from Peary's base than the North Pole. 



