174 DEEP BOREHOLE SURVEYS AND PROBLEMS 



zero line on the record paper. It is the inking device, 

 for in the lower end of it is a pen resting on the 

 horizontally extended paper below. When the hole devi- 

 ates the recording unit swivels on its pivots in the housing 

 so that the weighted side comes to rest on the lower side 

 of the dip when the boring tool to which the whole is 

 attached is at rest. The pendulum swings inward and 

 the movement of the pen is here governed by a toothed 

 segment (Fig. 113) whose teeth mesh in the sliding arm to 

 which the pen is attached. Figure 113 shows the cylindri- 

 cal bob securely fastened to the segment.^ When the 

 bob moves inward the pen moves outward to maintain its 

 contact with the paper. The paper is divided into 5-deg. 

 spaces by vertical lines so that when the instrument is 

 vertical the pen rests on the zero line, the degree of accuracy 

 being claimed as greater than that of the acid-bottle 

 method. As the apparatus is run into the hole its body will 

 swing around on the ball-bearing end pivots or sockets, 

 and the pen arm and segment will swing as the plumb 

 sways with the motion. Thus we get the jagged hori- 

 zontal lines observed during each reading and during the 

 ''pull out" shown at the bottom of Fig. 114, which is a 

 half-hour record from a well in the Little River Pool in 

 Oklahoma. No calculations are needed when the record 

 comes out of the hole. The whole is protected by a suit- 

 able steel case. It is secured to the working tool in the 

 hole, i.e., bailer, sandpump or drill pipe and read at each 

 extraction of these. It suits 6^^ or 8-in. casing. 



^ By the courtesy of Oil Field Engineering, issue of Sept. 1, 1929. 



