ADVANCES IN OIL PROSPECTING 137 
on the operation of these ratiometers and their theory, the publica- _ 
tion by Edge and Laby (pp. 50-54, and 268-274) (ref. list No. IV3) — 
. should be consulted. 
. 
fa POTENTIAL @RATIOMETERS 
#* ‘ 
PLY 6 3 Tomo RE 
ye 

Fic. 25.—View of I.E.G.S. ratio compensator. 
Il. INTERPRETATION 
Methods of interpretation of potential-drop-ratio results have 
been worked out in a general way for Koenigsberger’s and for the 
Swedish American methods. 
The results of the computations show that Koenigsberger’s 
method is, in a number of ways, at a disadvantage as compared with 
the Swedish method, because his ratios are only opposite but not 
equal for good and poor conductors which have the same conductivity 
ratio. What is meant by this is the following: If we form, for a 2-layer 
problem, the ratio of the conductivity of the surface layer to the con- 
‘ductivity of the lower layer, then the potential-drop ratio in Koenigs- 
berger’s method is 3.57 if the conductivity ratio is one (homogeneous 
ground). However, if the conductivity ratio is 10:1, the potential 
ratio decreases only to 2.48, whereas, in the converse case (if the con- 
ductivity ratio is 1:10) the potential ratiois 8.70 (Fig. 40 c). Thus, it 
is seen that in his method the potential-drop-ratio responses are not 
symmetrical around the 3.57 position, and that the influence of good 
467 
