HAEMONIC AXAI.YSIS AXD PREDICTION OF TIDES, 



15T 



In the use of this form it will be noted that the R's and f 's refer- 

 ring to component B are to be the best known values whether derived 

 from the analysis or by inference, but the R' and f ' of component A^ 

 entered as items (9) and (19), respectively, must be the unmodified 

 values as obtained directly by Form 194. 



Form 4-44j standard harmonic constants for predictions (fig. 33) . — 

 This form provides for the compilation of the harmonic constants 

 for use in the prediction of the tides and also for certain permanent 

 preliminary computations to adapt the constants for use with the 

 U. S. Coast and Geodetic Survey tide-predicting machine No. 2. 

 The form is used in a loose-leaf binder. 



The components are listed in an order that conforms to the arrange- 

 ment of the corresponding component shafts and cranks on the pre- 

 dicting machine. The accepted amplitudes and epochs a,re to be 

 given in the columns provided for the purpose. At the bottom of the 

 page a space is provided for indicating the source from which the con- 

 stants were derived. 



The column of Remarks provides for miscellaneous information 

 pertaining to the predictions. This includes the kind of time in 

 which the predictions are to be given — the approximate extreme 

 range of tide at the place for determining the proper scale to be 

 used, the height dial, the marigram gear, the marigram scale, and 

 the datum to which the predicted heights are to be referred. 



The extreme range may be estimated from the predictions for a 

 preceding year or may be taken approximately as twice the sum of 

 the amplitudes of the harmonic constants. The height dial, mari- 

 gram gear, and marigram scale which are recommended for use with 

 different extreme ranges are given in the table below. 



Working scale, height dial, marigram gear, and scale. 



(1) 



Extreme range (feet). 



0.0- 2.5 

 2.&- 3.6 

 3.6- 4.5 



4.6- 7.0 

 7.1- 9.5 

 9.6-10.5 



10.6-14.5 

 14.6-19.5 

 19.6-20.5 



20.6-29.5 

 29.6-39.5 

 39.6-.... 



(5) 



Mari- 

 gram 

 scale. 



(6) 



Mari- 

 gram 

 1-inch 

 tide. 



Feet. 

 0.50 

 0.67 

 1.00 



1.25 

 1.67 

 2.50 



2.50 

 3.33 

 5.00 



5.00 

 6.67 

 10.00 



(7) 



Mari- 

 gram 

 limit 

 tide. 



Feet. 

 3.0 

 4.0 

 6.0 



7.5 

 10.0 

 15.0 



15.0 

 20.0 

 30.0 



30.0 

 40.0 

 60.0 



(8) 



Tide 

 1-foot 

 mari- 

 gram. 



Inches, 

 2.0 

 1.5 

 1.0 



0.» 

 0.6- 

 0.4 



0.4 

 0.3 

 0.2 



0.2 



0.15 



0.1 



Column (1), or extreme range, is the argument for determiniag the working scale and marigram gear for 

 each station. 



Column (2) contains the factor to reduce the amphtudes of the harmonic constants to the working scale, 



Colmnns (3) and (4) contain the height dial and marigram gear that should be used for ranges of tide 

 within the limits indicated in column (1). 



Column (5) gives the height scale of the tide curve. 



Column (6) shows the amount of rise or fall of the tide represented by each inch, vertical measure, on the 

 marigram. 



Column (7) gives the extreme range of tide that can be represented on the marigram, which is 6 inches 

 wide, with the different marigram scales. 



Column (8) shows the amount of rise and fall on the marigram for each foot of actual tide. 



