232 



GRAVITATIONAL METHODS 



[Chap. 7 



with B north and south and A east and west. For ?7„„ A is north and 

 south, and B east and west. 



Fig. 7-796. Jung diagram (C) for terrain curvatures. 



The evaluation of lines of equal elevation becomes unnecessary in a 

 method using vertical diagrams proposed by the author. ^"^ These dia- 

 grams are placed through the surrounding 

 terrain in sixteen azimuths; the terrain 

 profile is superimposed on the diagram; and 

 a count is made of the number of elements 

 which are included between the horizon 

 (through the center of gravity of the in- 

 strument) and the terrain profile. The 

 calculation of these diagrams is based on a 

 determination of the effect of a segment of 

 a spherical shell, such as that shown in 

 Figs. 7-80 and 7-81. Substituting in eqs. 

 Fig. 7-80. Mass element in ref- (^-66) r sm ^ COS a for x, r sin <p sin a 

 erence to torsion balance. for y, and r COS ip for z, the equations 



»«A.A.P.G. Bull., 13(1), 39-74 (Jan., 1929). 



