6 



U. S. COAST AND GEODETIC SURVEY 



19. Names of parts. — For convenience of reference there are given 

 below the names applied to different parts of the standard automatic 

 tide gage. The numbers correspond to those given in figures 4 to 9. 



1. Time clock. 



2. Motor clock. 



3. Clock case. 



4. Supply roller. 



5. Tension guide spi'ings (2). 



6. Pencil screw. 



7. Pencil arm return springs (2). 



8. Drum shaft ball bearings (2). 



9. Drum shaft bearing caps (2). 



10. Counterpoise drum or reel. 



11. Float drum or reel. 



12. Capstan lock nut, counterpoise 



drum. 



13. Capstan lock nut float drum. 



14. Main roller. 



15. Bracing rod. 



16. Tension weight drum or reel. 



17. Receiving roller. 



18. Receiving roller release buttons 



(2). 



19. Winged nuts securing clock unit 



(4). 



20. Datum pencil rod. 



21. Datum pencil clamp. 



22. Datum pencil holder clamping nut. 



23. Datum pencil holder. 



24. Datum pencil. 



25. Datum pencil clamping screw. 



26. Hour-tripping rod. 



27. Clamping strews, tripping rod as- 



sembly (2). 

 2S. Tripping hook stop. 



29. Striker weight. 



30. Striker weight clamping screw. 



31. Striker weight spring. 



32. Striker lifter binding sci'ew. 



33. Striker lifter. 



34. Carrier arm. 



35. Carrier wheel. 



36/ Hour tripping hook. 



37. Recording pencil. 



3S. Recording pencil holder. 



39. Recording pencil clamping screw. 



40. Pencil holder adjusting screw. 



41. Pencil arm. 



42. Pencil weight. 



43. Pencil arm bearing screw. 



44. Pivot screws for pencil holder (2). 



45. Capstan bearing pin for pencil 



screw. 



46. Lock screw. 



47. Lock nut. 



20. Clock unit. — The clock unit consists of two clocks mounted on 

 a frame. The one on the right (1, fig. 4) is known as the time clock 

 and the one on the left (2) without hands as the motor clock. For 

 convenience, the corresponding sides of the tide gage may be called 

 the time side and the rnotor side. The time clock operates the device 

 which makes the hour marks on the record, while the motor clock 

 serves to regulate the forward movement of the paper. By having a 

 separate clock to move the paper, the time clock is relieved of unnec- 

 essary work and may therefore be more accurately regulated for 

 recording the correct time. Moreover, the use of two clocks aids in 

 securing a continuous record, because if either one of the clocks stops 

 for a short period, it is sometimes possible to interpret the record 

 during this period through the functioning of the remaining clock. 



21. The clock unit is secured by four winged nuts (19, fig. 8) on 

 the back of the clock case and is interchangable with other units when 

 replacements are necessary. ,In the older types of the instrument, the 

 two clocks were mounted independently in the clock case, the time 

 clock on the left and the motor clock on the right. 



22. Each clock has an 8-day movement and may be regulated and 

 corrected as similar clocks in ordinary use. To avoid injury to the 

 hour-marking device of the time clock, however, the minute hand must 

 not be turned backward when between 10 minutes before and 5 min- 

 utes after the hour "12." The hour hand may be turned in either 

 direction, and if it is necessary to turn the clock backward within the 

 limits noted above, it may be accomplished by turning the hour hand 

 back a full hour and the minute hand forward to the correct time. 



