ADVANCES IN OIL PROSPECTING 135 
Mn SO COD 2. 
62 
ie 
010 


oO ons 
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B 
Fic. 22.—a: Wiring diagram, Racom amplifier. Courtesy Swedish American Pros- 
pecting Corporation. b: Schematic diagram. 

Fic. 23.—View of Racom with amplifier and buzzer. 
465 
