166 C. A. HEILAND 
2g. L. Gilchrist, J. B. Mawdsley, A. S. Eve, D. A. Keys, H. C. I. Watson, J. H. 
Swartz, ‘Studies of Geophysical Methods, 1928-1929,” Canada Geol. Survey Mem. 165, 
No. 2266 (Ottawa, 1931), pp. 1-188. 
30. E. V. Potter, “Results of Electrical Resistivity and Electrical Induction Meas- 
eae at Abana Mines, Quebec, Canada,” U. S. Bur. Mines Tech. Paper sor 
(1931 
ed J. J. Jakosky, ‘‘Practical Aspects of Geophysical Surveys,” Arizona Min. Jour. 
(January 15, 1931), pp. 18-29. 
32. E. G. Leonardon, “ Plectrical Exploration Applied to Geological Problems in 
Civil Eneiicenng, ” Amer. Inst. Min. Met. Eng. Tech. Publ. 407 (February, 1931). 
33- Joel H. Swartz, “Resistivity Measurements upon Artificial Beds,” U. S. 
Bur. Mines Circ. of Inf. 6445, (February, 1931). 
34. L. Gilchrist, ‘(Measurements of Resistivity by the Central Electrode Method 
at the Abana Mine, ‘NW. Quebec, Canada,” Amer. Inst. Min. Met. Eng. Tech. Publ. 
386 (February, 1931). 
35. Bela Low, S. F. Kelly, and W. B. Greagmile “Applying the Megger Cart 
Tester in Electrical Exploration,” Geophysical Prospecting (Amer. Inst. Min. Met. 
Eng., 1952), pp. 114-26. 
36. M. K. Hubbert, “Results of Earth Resistivity Survey on Various Geologic 
Shaceetan Tlinois,” Amer. Inst. Min. Met. Eng. Tech. Publ. 463 (February, 1932). 
37. J. H. Swartz, ‘“<Oil Prospecting in Kentucky by Resistivity Methods.” U.S. Bur. 
Mines Tech. Paper 521 (1932). 
38. C. A. Heiland, “A Demonstration of the Geologic Possibilities of the Resistivity 
and Magnetic Prospecting Methods,” Terrestr. Magn. & Atmosph, Elec., Vol. 37, No. 3 
(September, 1932), pp. 343-50 
39. E. M. Poldini, ‘Les sondages électriques” Bull. techn. Suisse Romande, 1932.: 
4o. C. and M. Schlumberger and E. G. Leonardon, ‘‘Location and Study of Pipe 
Line Corrosion by Surface Electrical Measurements, ” Amer. Inst. Min. Met. Eng. 
Tech. Publ. 476 (February, 1932). 
4t. V. Melikian: ‘‘Electrical Survey of Limestones of the Bibi-Eibat Bay,” Azer- 
bayjanskoye Neffyianye Khozyaistro, Baku, Vol. 117-18, Nos. 9-10 (September- 
October, 1931), pp. 104-08. 
IV. POTENTIAL-DROP-RATIO METHODS 
1. J. Koenigsberger, “Zur Ermittlung ausgedehnter Schichten verschiedener Leit- 
eg ” Zeit. Geophysik, Vol. 6, No. 2 (1930), pp. 71-78. 
, “‘Neber geoelektrische Methoden mit direkter Stromzuleitung,” 
Galiate Beitrage, Suppl. 1 (1) (1930), pp. 23-109. 
3. A. Broughton Edge and T. H. Laby, The Principles and Practice of Geophysical 
Prospecting (Cambridge Univ. Press, 1931). “‘Potential-Drop-Ratio Method,” pp. 50- 
54, ake 268-74 
Geo Electrical Prospecting by A. C. Bridge Methods,” Chem. 
Eng. ve Min. Rev., Vol. 23, No. 27 (April 6, 1931), pp. 249-51; zbzd. , Nature, Vol. 127, 
Nos. 3192 and 3203 (January 3, 1931), Pp. 37-30. ; ; 
5. H. Lundberg and Th. Zuschlag, ““A New Development in Electrical Prospect- 
ing,” Geophysical Prospecting, Amer. Inst. Min. Met. Eng., New York, 1932, pp. 47-62. 
6. H. Lundberg and F. Kihlstedt, “‘Differential Rate of Change Method; Elimina- 
tion of Surface Resistivity: Variation in Electrical Prospecting,” Amer. Inst. Min. 
Met. Eng. Adv. Paper (February, 1932), 4 pp. 
7. H. Hedstrom, ‘Electrical Prospecting for Auriferous Quartz Veins and Reefs,” 
Mining Mag., Vol. 46, No. 4 (April, 1932), pp. 102-19. 


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