296 



DEEP BOREHOLE SURVEYS AND PROBLEMS 



Two slanting boreholes, problem, 



268 

 Two vertical boreholes, problem, 268 

 Types of surveys, 48 



U . 



Upham and Dixon's gyrostatic ap- 

 paratus, 85 

 Upstream boreholes, 250, 252 

 Upward deviation, 31 



Van Orstrand, C. E., cited, 36 

 Versine method, 277 

 Vertical borehole problems, 248 

 Vertical correction, 6 

 by alignment chart, 279 



Vibrometer, 239 

 Vivian's method, 57 



W 



Wache's plumbing device, 42 

 Walls of borehole photographed, 



177, 179 

 Waves, electrical, 226 



seismic, propagation of, 235, 243 

 Weak core barrels, 18 

 Wheatstone's gyroscope, 204 

 White, E. E., cited, 108 

 Wire plumbing, 42 

 Wiring diagrams, 142, 145 

 Wolff's apparatus, 59 



Z 



Zenith angle and plane, 114 



