HAEMOXIC ANALYSIS AjSTD PREDICTION OF TIDES. 151 



For the lunal solar components K^ and K2, items (14), (16), and 

 (23) to (37) may be omitted. 



*For the diurnal components Ji,Oi, 00, Pi,Qi,2Q, and p^jitems (5), 

 (6), and (14) to (34) may be omitted. 



For the semidurnal components L2, N,, 2N, R27 T,, Xj, fi-,, v-,, and 

 2SM, items (3), (4), (8) to (16), and (23) to (37) may be omitted. 



For terdiurnal components MK and 2MK, items (5), (6), (9), (12), and 

 (18) to (37) may_ be omitted. 



For quarter-diurnal components MN and MS, items (3), (4), (8) 

 to (25), and (35) to (37) may be omitted. 



In the bottom portion of the form the symbol of the component is 

 to be entered at the head of the column or columns indicated by the 

 subscript corresponding to the number of component periods in a 

 component day, the remaining columns being left blank. 



The hourly means from Form 142 (fig. 26) are entered as items (1) 

 and (2) in regular order, beginning with the mean for hour. Item 

 (4) consists of the last five values of item (3) arranged in reverse 

 order. Item (6) consists of the last six values of item (5) in their 

 original order. For the computations of this form the following 

 tables will be found convenient: Table 19 of this publication for 

 natural products, Vega's Logarithmic Tables for logarithms of linear 

 quantities, and Bremiker's Funfstellige Logarithmen for logarithms 

 of the trigonometrical functions. In the last table the angular argu- 

 ments are given in degrees and decimals. 



In choosing between items (44) and (45) the former should be used 

 if the tabular value of (41) in the first quadrant is greater than 45° 

 and the latter if this angle is less than 45°. 



In referring (41) to the proper quadrant it must be kept in mind 

 that the signs of the natural numbers corresponding to (38) and (39) 

 are respectively the signs of the sine and cosine of the required 

 angles. Therefore (41) will be in the first quadrant if both s and c 

 are positive, in the second quadrant if s is positive and c negative, in 

 the third quadrant if both s and c are negative, and in the fourth 

 quadrant if s is negative and c positive. 



In obtaining (49) use (46) + (47) for all components except -S', and 

 (46) + (48) for component S. The log factor F for item (50) may be 

 obtained from Form 244a. 



Form 194 is designed for use when 24 component hourly means 

 have been obtained and all the original hourly heights have been 

 used in the summation. If in the summation for a component each 

 component hour of the observation period received one and only one 

 of the hourly heights, it will be necessary to take the log-augmenting 

 factor from Table 20 and add this to the sum of items (46) and (48) 

 to obtain item (49) , striking out item (47) . 



This form is also adapted for use with the long-period components. 

 Assuming that the daily means have been cleared of the eJBFects of 

 the short-period components in accordance with section 31, and 

 that these means have been assorted into 24 groups to cover the 

 component period, the 24 group means may then be entered in 

 Form 194 in place of the 24 hourly means used for the short-period 

 components. Then, treating the components Mm and Sa the same 

 as the diurnal tides and the components Mf, Msf, and Ssa as the 

 semidiurnal tides, the form may be followed except that the log- 

 augmenting factor must be taken from Table 20 and then combined 

 with items (46) and (48) to obtain item (49), striking out item (47). 



