670 



Subsurface Geologic Methods 



the window will be clean when the camera reaches the section of the well 

 to be photographed. 



Operating Equipment 



The equipment used to operate the camera includes a special non- 

 rotating stranded steel cable, the core of which is a rubber-covered elec- 

 trical conductor. The metal sheath of the cable serves as the path for the 

 return circuit. This cable is attached to a hoisting winch that has com- 

 mutator rings enabling the cable to be raised and lowered in the well bore 



Figure 358. Fragment of gypsum that may actually be included in the rock, although 

 shadows around the edge would seem to indicate a possibility that fragment is 

 merely adhering to wall of well (2,429 feet) . 



without breaking the electrical circuit. A portable 110-volt alternating- 

 circuit generator and an instrument panel containing a voltmeter and an 

 ammeter with suitable control switches for operating the camera are also 

 provided. This equipment is mounted in a large panel-bodied truck so 

 arranged that the truck motor drives the hoisting winch. The depth of the 

 camera in the well bore is determined at all times by running the cable 

 over a measuring wheel, which is connected by selsyn motors to a depth 

 counter on the operating panel of the truck. 



