BORE-HOLE INVESTIGATIONS 1119 



2,401,371 Issued June 4, 1946. J. M. Pearson and C. R. Nichols. "Electrical Pros- 

 pecting Method and Apparatus." 



2,404,132 Issued July 16, 1946. T. T. Hayward. "Apparatus for Use in Logging 

 Wells." 



2,404,622 Issued July 23, 1946. R. L. Doan. "Well Logging Apparatus." 



2,411,843 Issued Dec. 3, 1946. C. B. Aiken. "Compensating Means for Electrical 

 Borehole Apparatus." 



2,414,862 Issued Jan. 28, 1947. R. E. Fearon. "Well Surveying Apparatus." 



2,414,899 Issued Jan. 28, 1947. W. Al. Rust, Jr. "Well Logging." 



2,421,423 Issued June 3, 1947. S. Krasnow. "Method and Apparatus for Taking 

 Physical Measurements in Boreholes." 



2,428,034 Issued Sept. 30, 1947. C. R. Nichols and S. H. Williston. "Electrical Pros- 

 pecting Apparatus." 



2,428,155 Issued Sept. 30, 1947. H. Guyod. "Method and Apparatus for Logging 

 Boreholes." 



2,433,746 Issued Dec. 30, 1947. H. G. Doll. "Method and Apparatus for Investigating 

 Earth Formations Traversed by Boreholes." 



2,436,503 Issued Feb. 24, 1948. J. Y. Cleveland. "Delayed Well Logging." 



2,438,518 Issued March 30, 1948. R. G. Piety. "Circuit for Measuring Voltage of an 

 Alternating Source." 



2,441,065 Issued May 4, 1948. W. G. Green. "Apparatus for Well Logging." 



2,446,303 Issued Aug. 3, 1948. J. E. Owen. "Well Logging Apparatus." 



2,446,527 Issued Aug. 10, 1948. M. E. Chun and J. C. Stick, Jr. "Phase Shift Logging 

 of Well Bores." 



2,450,060 Issued Sept. 28, 1948. R. Ring. "Well Surveying Instrument." 



2,455,940-2 Issued Dec. 14, 1948. M. Muskat and N. D. Coggeshall. "Method of Geo- 

 physical Exploration by Microwaves." 



GAMMA-RAY LOGGING 



2,275,456 Issued March 10, 1942. J. Neufeld. "Method and Apparatus for Radioactive 

 Investigation of Drill Holes." 



2,275,747-8 Issued March 10, 1942. R. E. Fearon. "Well Survey Method and Appa- 

 ratus." 



2,284,345 Issued May 26, 1942. C. H. Schlesman. "Method and Apparatus for Geo- 

 physical Prospecting." 



2,285,840 Issued June 9, 1942. S. A. Scherbatskoy. "Well Survey Method and 

 Apparatus." 



2,288,278 Issued June 30, 1942. L. G. Howell. "Gamma-Ray Well Logging." 



2,296,176 Issued Sept. 15, 1942. J. Neufeld. "Well Survey Method and Apparatus." 



2,298,794 Issued Oct. 13, 1942. L. G. Howell. "Well Logging." 



2,309,835 Issued Feb. 2, 1943. R. E. Fearon. "Well Logging Apparatus and Method 

 Thereof." 



2,316,361 Issued April 13, 1943. R. G. Piety. "Method and Apparatus for Surveying 

 Wells." 



2,323,484 Issued July 6, 1943. J. Neufeld. "Well Logging Method and Apparatus." 



2,345,119 Issued March 28, 1944. D. G. Hare. "Subsurface Prospecting." 



2,349,225 Issued May 16, 1944. S. A. Scherbatskoy, G. Swift, R. E. Fearon and 

 J. Neufeld. "Well Logging Instrument." 



2,349,712 Issued May 23, 1944. R. E. Fearon. "Well Logging Method and Device." 



2,349,753 Issued May 23, 1944. B. Pontecorvo. "Method and Apparatus for Geophys- 

 ical Exploration." 



2,351,028 Issued June 13, 1944. R. E. Fearon. "Well Surveying Method and Appa- 

 ratus." 



2,358,574 Issued Sept. 19, 1944. L. G. Howell. "Gamma-Ray Well Logging." 



2,365,763 Issued Dec. 26, 1944. B. J. Kalb and D. H. Wise. "Well Logging Device." 



2,369,550 Issued Feb. 13, 1945. A. Frosch. "Well Logging." 



2,391,093 Issued Dec. 18, 1945. L. G. Howell. "Radioactivity Well Logging." 



NEUTRON LOGGING 



2,220,509 Issued Nov. 5, 1940. Folkert Brons. "Process and Apparatus for Exploring 



Geological Strata." 

 2,231,577 Issued Feb. 11, 1941. D. G. C. Hare. "Locating Cement." 



