ELECTRICAL PROBING WITH AN APPARATUS IN WATER 195 



for m > Hq 



- u (39) 



and for m < Hq 



^ = ^^< 



l + jti 



9max I (-^-^'max ^^m) 



I 



o - w 39' 



^ 1 + /J, 



Given a certain degree of accuracy (in our case the accuracy taken was 

 d — 0.005, or 0.5%), it is possible to select such a number m of terms of 

 the sum, to satisfy the inequality 



100(l + /f) l^maxl 



or 



which ensures the given accuracy S. 



This operation is readily carried out by means of a slide rule and an 

 appropriate table for the function l^. For most of the probe curves for any 



value of -y- the value //i for an accuracy d = 0.5% lies within the limits of 



1-15 and does not exceed 35. 



REFERENCES 



1. L. M. Al'pin, The Theory of Dipole Probes. Gostoptekhizdat, (1950). 



2. V. V. BuRGSDORF, Calculation of earthings in heterogeneous grounds. Elektrichestvo 



No. 1. (1954). 



3. L. L. Van'yan, Theoretical Curves for Electrical Sea probing with a sea-bottom 



apparatus. Applied Geophysics No. 50. Gostoptekhizdat, (1956). 



4. V. N. Dakhnov, Electrical Prospecting of Petroleum and Gaseous Deposits. Gos- 



toptekhizdat, (1953). 



5. A. I. Zaborovskii, Electrical Prospecting. Gostoptekhizdat, (1943). 



6. S. Ya. LiTviNOV, Electrical Sea Prospecting. Gostoptekhizdat, (1941). 



7. R. Maie, Mathematical Basis for Electrical Prospecting with a Direct Current. ONTI. 



(1935). 



8. G. D. TsEKOV, A Method for Calculating Multilayer Curves of Vertical Electrical 



Probing for a Case where the Underlying Medium is in the Form of Rocks of Very 

 High or Very Low Resistance. Thesis. Documents VNII Geofizika. 



9. K. Flathe, a practical method of calculating geoelectrical model graphs for horizon- 



tally stratified media. Geophysical Prospecting, vol. 3. (1955). 



13' ' 



