Tables 120, 121 



TERRESTRIAL MAGNETISM. 



TABLE 120. — Total Intensity ol the Terrestrial Magnetic Field. 



This table gives in the top line the tot.-il intensity of the terrestrial nias;nelic Ikld for the longitudes given in the first 

 column and the latitudes given in the body of the table. Under the headings 13, nS- a»^ ■3-75 "'fre are some- 

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

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

 for the epoch January i, 1SS5, and the intensities are in British and C. G. S. units. 



TABLE 121. —Secular Variation ol 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. 



• Tables 120-125 have been compiled from a very full discussion of the magnetic dip and intensitv for the United 

 States and adjacent countries, given in Appendix 6 of the Report of the United States Coast and Geodetic Survey 

 for 18S5. Later Reports of the survey have been consulted, particularly in connection with tlie extiaiiolition of the 

 values of horizontal intensity to 1890 and 1895, but most of the data are taken from Mr. Schott's Appendix to the 1885 

 Report. 

 Smithsonian Tables. 



no 



