5 8o 



Tables 735 and 736 (charts) 

 TERRESTRIAL MAGNETISM 



TABLE 735. — World Isoporic Lines for Vertical Intensity (Lines of Equal Annual 

 Change) Approximate Epoch 1920-1925 



TABLE 736. — World Isoporic Lines for Total Intensity (Lines of Equal Annual 

 Change) Approximate Epoch 1920-1925 



Smithsonian Tables 



