Figure 3.--Sectional view of bathykymograph. See text for explanation. 



6. One of two spacer rings used to mount 

 the recording drum to the piston housing. 



7. Pin. 



8. Keyway in piston shaft. This keyway 

 and pin 7 prevent the piston from rotating in 

 its housing. 



9. Setscrew to clamp the recorder drum 

 to the piston housing. 



10. Clock to piston coupler. One end is 

 threaded to the piston shaft; the other is bored 

 to receive the clock shaft which is secured by 

 the two setscrews. The coupler has been drawn 

 detached for clarity. It can be seen in position 

 in figure 2. 



11. Clock shaft. 



12. Clock housing. 



13. Lower edge of clock housing. This is 

 notched or knurled to fit the upper edge of the 

 recording drum. 



14. Upper edge of the recording drum. 



15. Ring for attaching the case to the net. 



16. Stylus assembly. This consists of a 

 spring arm (broken in figure 3) and a record- 

 ing point. The arm and point can be swung 

 aside while changing paper. 



