TABLES 12O, 121. 



TERRESTRIAL MAGNETISM. 



TABLE 120. - Total Intensity of the Terrestrial Magnetic Field. 



This table gives in the top line the total intensity of the terrestrial magnetic field for the longitudes given in the first 

 column and the latitudes given in the body of the table. Under the headings 13, 13.5, and 13.75 there are some- 

 times several entries for one longitude. This indicates that these lines of total force cut the same longitude line 

 more than once. The isodynamic lines are peculiarly curved and looped north of Lake Ontario. The values are 

 for the epoch January i, 1885, and the intensities are in British and C. G. S. units. 



TABLE 121. Secular Variation of the Total Intensity. 



Values in British units of total intensity of terrestrial magnetic force at stations given in the first column and epochs 

 January i of the years given in the top line. 



SMITHSONIAN TABLES. 



IIO 



