30 U. S. COAST AND GEODETIC SURVEY 
Station: Geter, Pras, Irby /- é, 194 
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Fig. 13.— Tide curves, Boston, Mass., plotted from hourly heights of the tide. 
indicating on the curve the beginning of the hour. Every day when the observer 
visits the tide station, he stamps and fills in the data of the note shown in Figure 14. 
This gives the necessary information for marking the successive hours of the day and 
for referring the heights on the curve to the tide staff. The observer reads the staff 
to the nearest half tenth of a foot if the water is free from waves, or to the nearest 
