IV. TABULATION OF THE TIDE RECORD 
Hourly Heights and High and Low Waters 
A complete tabulation of a tide record comprises two sets of tabulations, the first 
giving the hourly heights of the tide and the second the times and heights of the high 
and low waters. In addition to constituting a full and convenient record of the tide, 
these two tabulations furnish the data requisite for the determination of all tidal 
datum planes and the characteristic features of the tide. 
For convenience in tabulating and in filing, the Coast and Geodetic Survey makes 
use of printed forms 8 by 10% inches for tabulating the hourly heights and the high and 
low waters. Both sides of the sheets are used, one sheet of high and low waters covering 
a month and one sheet of hourly heights covering two weeks. Specimen copies of 
these forms are shown on a reduced scale in Figures 15 and 16. The wide spacing of 
the days on the form for hourly heights is brought about by the fact that these tabulated 
forms are used for other purposes in connection with certain stencils which require 
that particular spacing. 
The Record on Cross-Section Paper 
If the tide record is on cross-section paper, whether made by an automatic tide 
gage or plotted from staff readings, the tabulation is a relatively simple matter. Gen- 
erally no time corrections are necessary, since corrections up to three minutes are 
ignored; but should time corrections be necessary, the tabulator indicates them on the 
tide curves. The height of the tide pertaining to each hour of the day is then read 
from the tide curve and entered into its appropriate place on the hourly height form. 
The tabulation of the hourly heights for each sheet of curves is completed before taking 
up the tabulation of the high and low waters. A specimen page of hourly heights of 
the tide for the week beginning June 24, 1944, for Boston, Mass., 1s shown in 
Figure 15. 
The horizontal and vertical sums shown to the right and bottom in Figure 15 are 
obtained later in connection with the determination of mean sea level. The figures in 
the horizontal column ‘‘Day of series”’ give the sequence of each day with reference to 
the beginning of the series. When a tide station is continued for a number of years it 
is most convenient to begin each series of observations on the Ist of January and con- 
tinue the tabulation of the hourly heights consecutively throughout the year. Table 
2 gives the day of series, the page, and the column corresponding to the Ist of every 
month and the last day of the year for a series beginning January 1. This table serves 
as a convenient check to insure against the omission or duplication of a day in the tabu- 
lation of the hourly heights of the tide. 
On the sheet of hourly heights that has the tabulation for the last day of a month, 
the sum of the hourly heights is entered, and after dividing by the appropriate divisor 
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