MAGNETIC METHODS 245 



1,748,659 Issued Feb. 25, 1930. Karl Sundberg. "Method and Apparatus for Magnetic 

 Prospecting." 



1,792,639 Issued Feb. 17, 1931. H. N. Herrick. "Method and Apparatus for Deter- 

 mining the Direction of the Dip and Strike of the Earth's Strata." 



1,819,797 Issued Aug. 18, 1931. Seizo Shimizu. "Magnetometer." 



1,863,415 Issued June 14, 1932. Frank Richer. "Magnetometer." 



1,895,373 Issued Jan. 24, 1933. Ernest Bruche. "Apparatus for Measuring Magnetic 

 Fields." 



1,909,619 Issued May 16, 1933. Henry N. Herrick. "Measuring Instrument." 



1,943,850 Issued Jan. 16, 1934. Orley H. Truman. "Magnetometer." 



1,976,636 Issued Oct. 9, 1934. Erwin Roux. "Magnetic Balance for the Measurement 

 of Intensities." 



2,010,245 Issued Aug. 6, 1935. Erwin Roux. "Magnetic Balance." 



2,104,752 Issued Jan. 11, 1938. H. N. Herrick and E. D. Lynton. "Method and Means 

 for Determining Magnetic Polarity." 



2,149,717 Issued Mar. 7, 1939. J. M. Pearson. "Method and Apparatus for Cali- 

 brating Magnetometers." 



2,151,627 Issued Mar. 21, 1939. V. V. Vacquier. "Apparatus for and Method of 

 Measuring the Terrestrial Magnetic Field." 



2,196,314 Issued April 9, 1940. R. E. Lee. "Method of Measuring the Inherent Ter- 

 restrial Magnetism of the Earth's Crust." 



2,246,259 Issued June 17, 1941. L. Machts. "Apparatus for Making Geophysical 

 or other Measurements." 



2,252,059 Issued Aug. 12, 1941. G. Barth. "Method and a Device for Determining 

 the Magnitude of Magnetic Fields." 



2,261,030 Issued Oct. 28, 1941. W. P. Jenny. "Micromagnetic Prospecting Device." 



2,331,617 Issued Oct. 12, 1943. D. W. Moore, Jr. "Magnetic Field Responsive 

 Device." 



2,334,593 Issued Nov. 16, 1943. R. D. Wyckoff. "Apparatus for Measuring Magnetic 

 Fields." 



2,335,117 Issued Nov. 23, 1943. E. P. Harrison. "Magnetic Surveying Apparatus." 



2,358,027 C. J. Penther and F. B. Rolfson. 



2,374,166 Issued Apr. 24, 1945. L. F. Beach and J. C. Purves. "Magnetic Field 

 Responsive Device." 



2,376,883 Issued May 29, 1945. A. S. Riggs and H. H. Thompson. "Dynamic Earth 

 Inductor Compass." 



2,378,014 Issued June 12, 1945. P. P. Horni. "Methods of Determining the Effective 

 Range of Magnetic Detectors." 



2,379,716 Issued July 3, 1945. A. W. Hull. "Magnetic Field Gradient Meter." 



2.383.459 Issued Aug. 28, 1945. L. F. Beach. "Indicator for Magnetic Fields." 



2.383.460 Issued Aug. 28, 1945. J. C. Purves and L. F. Beach. "Magnetic Field 

 Responsive Device." 



2.383.461 Issued Aug. 28, 1945. O. E. Esval, R. S. Curry, C. F. Fragola, and L. F. 

 Beach. "Flux Valve Compass System." 



2,384,819 Issued Sept. 18, 1945. M. C. Depp. "Flux Valve." 



2,389,146 Issued Nov. 20, 1945. C. F. Fragola, M. C. Depp, and R. S. Curry, Jr. 



"Flux Valve." 

 Re. 22,699 Issued Nov. 27, 1945. A. A. Stuart, Jr. "Magnetic Compass." 

 2,390,051 Issued Dec. 4, 1945. G. Barth. "Means for Measuring Magnetic Fields." 

 2,393,974 Issued Feb. 5, 1946. R. S. Curry, Jr. "Gyro Flux Valve Compass System." 

 2,403,347 Issued July 2, 1946. M. C. Depp and C. F. Fragola. "Flux Valve." 

 2,403,669 Issued July 9, 1946. E. J. Martin and C. E. Grinstead. "Inductor Compass." 

 2,404,806 Issued July 30, 1946. H. A. D. Lindsey. "Submarine Detector." 

 2,406,870 Issued Sept. 3, 1946. V. V. Vacquier. "Apparatus for Responding to Mag- 

 netic Fields." 

 2,407,202 Issued Sept. 3, 1946. V. V. Vacquier. "Apparatus for Responding to Mag- 

 netic Fields." 

 2,410,039 Issued Oct. 29, 1946. L. F. Beach. "Magnetic Field Responsive Device." 

 2,412,046 Issued Dec. 3, 1946. S. C. Hoare. "Resonant Circuit Saturable Core 



Measurement Apparatus." 

 2,414,448 Issued Jan. 21, 1947. L. F. Carter. "Gyro-Magnetic Compass System." 

 2,414,654 Issued Jan. 21, 1947. F. W. Meredith. "Flux Valve." 



