292 



DEEP BOREHOLE SURVEYS AND PROBLEMS 



Curvature, incipient, 10 



Czuchow borehole, Upper Silesia, 25 



D 



Deep boreholes, 1, 8 



Denis-Foraky teleclinograph, 166 



Depth recorders, 26, 28 



Deviation, angular, 2, 274, 275 

 causes of, 1, 15 

 factors influencing, 54 



Diagrams, 170 



Diameters of boreholes, 18, 28, 29 

 change in, difficulties due to, 29 

 irregularities in, 29 

 shrinkage, causes of, 29 



Diamond-drilled holes, 3 



Dickenson, J., cited, 18 



Difficulties due to diameter change 

 in boreholes, 29 



Dip, of boreholes, 49, 250, 260, 264 

 of strata, 22, 96, 177, 179, 256 



Direction of beds, 256 



Disadvantages of fluid methods of 

 survey, 97 



Displacements, and depths of bore- 

 holes, 250, 251, 253, 264 

 horizontal and vertical, 2, 3, 6, 

 184, 203 



Dixon's gyrocompass device, 85 



Double pendulums, 211, 162 



Driftmeter, 151 



Driftmeter record, 53 



Drum devices, 190, 196 



E 



Electric coring, 231 

 Electrical geophysical methods, 225 

 Electrical liquefaction of gelatin, 109 

 Electrical methods of survey, 47, 



111, 113, 156, 166, 127, 148 

 Electrolytic registration, 113 

 Electromagnetic examination of 



ground, 226 

 Electromagnets, 158, 168 

 Equator and gyro-action, 209 

 Equi-potential lines, 145 

 and methods, 226, 227 



Equi-potential surfaces, 231, 232 

 Erlinghagen, O., quoted, 41, 76 

 Erlinghagen's apparatus, 156 

 External photographic devices, 176, 

 179 



Films, 175, 177, 179, 183, 189, 221 

 Fissured strata, 18, 182 

 Florin's method, 77 

 Fluid methods, 47, 95 

 Foraky depth recorder, 26 

 Foucault's law, 204, 212 

 "Freedom" of gyroscope, 205 

 Freezing-shaft holes, 7 

 Freise, F., cited, 62, 64, 76, 136 



G 



Gallacher's apparatus, 137 



Gelatine, 63, 102, 108 



Geological causes of deviation, 17 



Geophone, 240 



Geophonic or seismographic meth- 

 ods, 48, 240 



Geophysical methods of borehole 

 survey, 225 



Goniometers, 105, 108 



Goodman's apparatus, 80 



Goodrich, H. B., quoted, 6, 203 



Gothan's stratameter, 64 



Graphical problem for boreholes, 271 



Gravitation, 208 



Ground wave coefficients, 234, 235 



Gudgeon joints, 164 



Guide rods, 191 



Guide springs, 154, 188 



Gyro-axis, 209, 210 



Gyrocompass, 204, 211, 214, 217 



Gyroscopic compass methods, 204 



Gyrostatic methods of survey, 48, 

 83, 85, 204 



H 



Haddow's method, 121 



Hall and Armentrout's device, 83 



Hanna's inertia-rotor apparatus. 87 



