22 



U. S. COAST AND GEODETIC SURVEY 



and pawl (29, 28, fig. 13) during the ordinary operation of the gage 

 but may be turued by a clock key when it is desired to increase the 

 tension of the spring. The spring is about 18 feet long and is com- 



FiGUHE 13. — Portable automatic tide gage (detail of stylus and float drum). 



pletely wound by about 40 turns of the drum. The spring operates 

 in a bath of watch oil which is introduced through one of the screw 

 holes in the cover plate (32, fig. 13). 



49. To replace a broken spring proceed as follows: Loosen screw 

 (18, fig. 12) which holds the shaft connecting the float- wire drum with 



