152 



EXPLORATION GEOPHYSICS 



(Courtesy of Kendrick-Bellamy Co., Denver, Colo.) 

 Fig. 64 



curve may be drawn by inspection. If the time involved in a series of 

 stations between occupation of the base is not too great, this assumption 

 of linear change is not seriously in error on most days. It is good prac- 

 tice to reoccupy a base station about every hour during a day after the 

 initial set-up thereon. 



The latitude and longitude correction is entered in column 11. This 

 correction removes the natural increase or decrease in the earth's field 



