146 U. S. COAST AND GEODETIC SURVEY 
The values for column C may then be obtained by applying 360° 
to the negative values in column D. 
A429. Form 445, settings for tide-predicting machine (fig. 33).—This 
form is designed for the computations of the settings for the predicting 
machine for the beginning of each year of predictions. The forms 
are bound in books, a separate book being used for each year of 
predictions. This form is used in connection with Form 444, and 
for convenience the order of arrangement of the constituents is identi- 
cal in the two forms. The name of the station, the time meridian, 
the height dial, marigram gear, marigram scale, and datum plane 
are copied directly from Form 444. 
430. For the amplitude settings the amplitudes of column B of 
Form 444 are multiplied by the factors f from table 14 for the year for 
which the predictions are to be made. A convenient way to apply 
these factors is to prepare a strip of paper with the same vertical 
spacing as the lines on Form 444 and enter the factors f for the 
required year on this strip. The strip may then be placed alongside 
of column B of Form 444 and the multiplication be performed. The 
same strip will serve for every station for which predictions are to be 
made for the given year. It has been the recent practice to enter 
the amplitude settings to the nearest 0.05 foot as being sufficiently 
close for all practical purposes. 
431. For the dial settings for January 1, 0 hour, the Greenwich 
equilibrium arguments of (V,+u)’s from table 15 are to be applied, ac- 
cording to the indicated sign, to the angles of column C or D of Form 
444, using the angle in column D if it is less than the argument, 
otherwise using the angle in column C. For the application of the 
(V,+w)’s a strip similar to that used for the factors f should be pre- 
pared. The same strip will serve for all stations for the given year. _ 
For the dial settings it is customary to use whole degrees, except for 
constituent M,, for which the setting is carried to the first decimal 
of a degree. 
432. The settings for February 1 and December 31 are used for 
checking purposes to ascertain whether there has been any slipping 
of the gears during the operation of the machine. To obtain the dial 
settings for February 1, 0°, and December 31, 24", prepare strips 
similar to those for the f’s and (V,+w4)’s. On one enter the angular 
motion of the constituents from January 1, 0", to February 1, 0"; on a 
second and a third strip, the angular motion for February 1, 0°, to 
December 31, 24°, for a common and leap year, respectively. For 
checking purposes a fourth and fifth strip may contain the angular - 
changes for a complete common and a complete leap year, respectively. 
The values for these strips may be obtained from table 36. These 
strips will be found more convenient if arranged with two columns 
each, one column containing the values in a positive form and the 
other column containing the equivalent negative value: which is 
obtained by subtracting the first from 360°. These strips are good 
for all years, distinction being made between the common and leap 
years. By applying the first strip to the dial settings for January 
1 the values for February 1 are readily obtained, and by applying 
the second or third strip to the latter settings those for the end of 
the year are obtained. The values obtained by applying the fourth 
or fifth strips to the settings for January 1 should also give the correct 
setting for the end of the year, and thus serve as a check. The 
