ELECTRICAL METHODS 635 



1,878,109 Issued Sept. 20, 1932. James D'Argaville Clark. "Means for Determining 



the Moisture Content and Quality of Materials." 

 1,882,113 Issued Oct. 11, 1932. Stephen W. Borden. "Earth Electrode Meter." 

 1,884,364 Issued Oct. 25, 1932. Karl Sundberg. "Method of Mapping Subsurface 



Structures." 

 1,884,419 Issued Oct. 25, 1932. Charles F. Wagner. "Means for Simulating Mutual 



Impedance." 

 1,884,496 Issued Oct. 25, 1932. Theodor Zuschlag. "Electrical Prospecting Apparatus." 

 1,887,915 Issued Nov. 15, 1932. Stephen W. Borden. "Earth Ohmmeter." 

 1,893,311 Issued Jan. 3, 1933. Thomas S. West. "Process of Locating Buried Pipe 



Lines, Etc." 

 1,897,688 Issued Feb. 14, 1933. Richard Ambronn. "Method of and Apparatus for 



Electric Earth Exploration." 

 1,902,265 Issued Mar. 21, 1933. Frank Rieber. "Electrical Prospecting System." 

 1,906,271 Issued May 2, 1933. John J. Jakosky. "Method and Apparatus for Deter- 

 mining Underground Structure." 

 1,910,021 Issued May 23, 1933. Buell B. Legg. "Soil Testing Apparatus." 

 1,910.820 Issued Aiay 23, 1933. Glenn E. Blinn. "Detector for Hidden Metal." 

 1,910,418 Issued May 23, 1933. Theodor Zuschlag. "Determination of Electrical 



Characteristics of Electrical Conductors." 

 1,910,709 Issued May 23, 1933. Magne Mortenson. "Electrode for Geophysical 



Surveys." 

 1,912,036 Issued May 30, 1933. Erik H. Hedstrom and Theodor Zuschlag. "Method 



of Determining the Direction of Alternating Ground Fields." 

 1,917,417 Issued July 11, 1933. Theodor Zuschlag. "Method and Apparatus for 



Measuring Alternating Electromotive Forces and Impedances." 

 1,919,215 Issued July 25, 1933. Ross Gunn. "Thunderstorm or Electric Field and 



Potential Indicator." 

 1,919,538 Issued July 25, 1933. Guy A. Stone. "Process and Apparatus for Making 



Electrical Measurements." 

 1,926,212 Issued Sept. 12, 1933. C. R. Nichols and S. H. Williston. "Electrical 



Prospecting." 

 1,931,223 Issued Oct. 17, 1933. Thomas R. Harrison. "Potentiometer Instrument." 

 1,934,079 Issued Nov. 7, 1933. Hans T. F. Lundberg and Folke H. Kihlstedt. 



"Electrical Prospecting." 

 1,934,447 Issued Nov. 7, 1933. Norman H. Ricker. "Means and Method of Electrical 



Prospecting." 

 1,936,796 Issued Nov. 28, 1933. J. W. Legg. "Testing Device." 



1.938.534 Issued Dec. 5, 1933. Leo J. Peters. "Method and Apparatus for Electrical 

 Prospecting." 



1.938.535 Issued Dec. 5, 1933. Leo J. Peters. "Method of and Apparatus for 

 Electrical Prospecting." 



1,940,340 Issued Dec. 19, 1933. Theodor Zuschlag. "Electrical Prospecting. 

 1,944,315 Issued Jan. 23, 1934. James K. Clapp. "Electric System and Method." 

 1,945,283 Issued Jan. 30, 1934. Harold S. Loomis. "Resilient Tire Construction for 



Track Circuit Shunting." 

 1,951,386 Issued Mar. 20, 1934. Theodor Zuschlag. "Electrical Prospecting." 

 1,951,716 Issued Mar. 20, 1934. Russel H. Varian. "Apparatus for Geophysical 



Exploration." 

 1,957,477 Issued May 8, 1934. L. Alan Sharp and James Pullman. "Detector." 



1.960.027 Issued May 22, 1934. Norman H. Ricker. "Method of Electrical 

 Prospecting." 



1.960.028 Issued May 22, 1934. Norman H. Ricker. "Means of Electrical 

 Prospecting." 



1,964,141 Issued June 26, 1934. Harold A. Rhodes and Frank A. Cowan. "Impedance 



Measuring Circuits." 



1,966,105 Issued July 10, 1934. Johann B. Ostermeier. "Method of and Apparatus 



for Searching for Ores." 



1,971,310 Issued Aug. 21, 1934. Alfred W. Barber. "Measuring Reactance." 



1,976,154 Issued Oct. 9, 1934. Herbert Walters. "Ground Contact for Vehicles." 



1,978,440 Issued Oct. 30, 1934. Edgar R. Shepard. "Electrical Measuring Device." 



1,997,163 Issued April 9, 1935. Theodor Zuschlag. "Electrical Prospecting." 



