PHOTOGRAPHIC METHODS 



201 



employed in California. It is about 2>yi in. in diameter 

 and about 7 ft. long (Fig. 140) and is capable of taking 88 

 records each trip, the distance between each setting being 

 at the control of the operator. The survey can thus be 

 made in a normal round trip and usually at the rate of 1,000 

 ft. in 70 min. 



Fig. 140. — Anderson oil-well Fig. 141. — Demonstration frame with 



survey apparatus about to be the machine set for certain inclination 



lowered in hole, with stands of from the vertical, 

 drill pipe set back in the derrick. 



The apparatus, including the pendulums, photographic 

 equipment, timing and actuating devices, is all contained 

 in a watertight welded casing which is constructed to 

 be run into the well on the end of a string of drill pipe or 

 tubing. Thus it can be used in mud and water. It is 

 generally run on tubing or drill pipe, although in the case 

 of one Pan-American well it was run on a sand line. In 



