638 EXPLORATION GEOPHYSICS 



2,375,778 Issued May IS, 1945. H. M. Evjen. "Apparatus for Making Geophysical 



Explorations." 

 2,376,659 Issued May 22, 1945. H. Chireix. "Apparatus for Detecting Underground 



Objects." 

 2,378,440 Issued June 19, 1945. G. N. Scott. "Process and Means for Measuring 



Soil Resistivity and Certain Electrical Characteristics Associated with a 



Buried Pipe Line." 

 2,382,093 Issued Aug. 14, 1945. S. R. Phelan. "Method for Making Geophysical 



Surveys." 

 2,382,743 Issued Aug. 14, 1945. C. J. Penther and F. B. Rolfson. "Electromagnetic 



Apparatus for Pipe-Line Surveys." 

 2,383,855 Issued Aug. 28, 1945. C. W. Hansell. "Potential Ratio-Controlled Ampli- 

 fier." 

 2,389,432 Issued Nov. 20, 1945. C. W. Hansell. "Communication System by Pulses 



Through the Earth." 

 2,393,717 Issued Jan. 29, 1946. D. M. Speaker. "Electronic Surgical Metal Body 



Locator." 

 2,407,363 Issued Sept. 10, 1946. W. H. Bussey. "Electrical Apparatus." 

 2,413,788 Issued Jan. 7, 1947. W. E. Sargeant and H. B. Hoeper. "Amplifier for 



Small Voltages." 

 2,417,609 Issued Mar. 18, 1947. D. S. Muzzey Jr. and R. D. Miller. "Electronic 



Commutator." 

 2,419,833 Issued April 27, 1947. H. E. Grimes. "Antenna Arrangement for Induction 



Communication System." 

 2,426,918 Issued Sept. 2, 1947. W. M. Barret. "Method for Electromagnetic-Wave 



Investigations of Earth Formations." 

 2,428,360 Issued Oct. 7, 1947. E. N. Dingley, Jr. "Electrical Guidance System for 



Surface Vessels." 

 2,437,134 Issued Mar. 2, 1948. A. L. Smith. "Electrode Assembly for Moisture 



Meters." 

 2,437,455 Issued Mar. 9, 1948. S. Berman. "Locator." 

 2,437,697 Issued Mar. 16, 1948. L. Kalom. "Electrical Probe." 

 2,440,693 Issued May 4, 1948. F. W. Lee. "Method for Determining the Subterranean 



Extension of Geologic Bodies." 

 2,442,805 Issued June 8, 1948. W. E. Gibson. "Metal Locator." 

 2,447,444 Issued Aug. 17, 1948. P. M. Waite. "Ground Stake." 

 2,449,313 Issued Sept. 14, 1948. A. H. Naef. "Ground Connecting Device." 

 2,454,911 Issued Nov. 30, 1948. D. H. Clewell. "Geological Exploration System." 



