29

C—la,

Other Values of the Harmonic Tidal Constants for Wellington, New Zealand. Latitude, 41° 17' S.; longitude, 174° 46' E. (1.) (2.) (1.) (2.) A o 37-742 X iH 0-060 0-029 ill 0089 0-108 2 \k 339 308 |k 325 308 p IH 0-028 0-023 M iH 0-007 r U 67 275 M > Ik 106 o IH 0-019 M IH 1-598 1-702 V U 13 m * U 137 123 T IH 0-034 M iH 0045 Ik 71 M * U 332 IST ,H °' 353 0449 iH 0-015 U 104 83 M » Ik 135 IH 0-068 n IH 0-099 0-121 v U 108 v Ik 36 194 o IH 0-241 0-073 |H 0085 0-071 5a (k 54 295 *» Ik 81 275 „ |H 0-035 0-204 esa Ik 240 212 1. Tide Tables for the year 1911, p. 456, U.S. Coast and Geodetic Survey, Washington: Hourly ordinates for one calendar year, 1894. 2. Harmonic Tidal Constants for ceitaiu Chinese and New Zealand Ports, by Thomas Wright, Proc. Eoyal Society, London, A. Vol. 83, p. 127: Times and heights of high and low water for the year 1901. Prediction. The predictions depend on a graphic method, controlled by calculation. Schedule No. lis prepared giving the times of high and low water of the M 2 tide throughout the year. Column 1 gives the consecutive number of the M 2 high water; column 2, the month ; column 3, the day of the month; column 4, the state of the M 2 tide, high or low water ; column 5, the mean solar times in hours and decimals of M 2 high and low waters ; column 6, the correction to the M 2 times as obtained from diagram (see Fig. 2) ; column 7, the corrected time of high and low waters of the tide ; column 8, the heights in feet and decimals as scaled from the diagram (see Fig. 2) ; column 9, the correction to the heights due to the long-period tides ; column 10, the corrected heights of high and low water. The times in column 5 are New Zealand civil mean time : 0 h. is midnight, 12 h. is noon, and 24 h. is midnight. Beginning with the time of the first high water of M 2 after noon on Ist January, 1912 — i.e., 16-12 hours —and adding to it on the calculating-machine the interval between the M 2 times of high and low water ( = 6-2103006 h.), the other times in column 5 are readily obtained. Independent checks are applied periodically.

Schedule No. 1. — Example for Auckland Tides for Year 1912.

Schedule No. 2 gives the differences between the high-water times of M 2 and of each of the component tides at intervals of ten M 2 tides. The initial entries are obtained from the following table, for Auckland, 1912, Ist January : —

Tide. Month. Day. State of ' M 2 Time. Tide. (4.) (5.) . Correction from Diagram. (6.) Corrected Time. Height from Diagram. Correction from long period tides. Corrected Height. (1-) (2-) (3-) _ (7.) (8.) (9.) (10.) h. 16-12 22-33 4-54 10-75 16-96 h. h. Ft. Ft. It. 0 1 January j> 1 2 H. L. H. L. H. 2 )t 3 153 154 March )> J? , . ! 20 21 21 21 21 22 22 H. L. H. L. H. L. H. 20-47 2-68 8-89 15-10 21-31 3-52 9-73 -0-04 -0-36 - 0-19 -0-36 0-20 -0-59 -0-36 20-43 2-32 8-70 14-74 21-11 2-93 9-37 8-54 0-71 903 0-16 8-76 0-48 9-10 -0-14 -0-14 -0-14 -0-14 -0-14 -0-14 -0-14 8-40 0-57 8-89 0-02 8-62 0-34 8-96 155 156

Tide. K V 0 + u. = K-(V O + U). Speed. t Differenoe from M 2 Time. Speed. Deg. M 2 204-9 N, 174-3 S 2 265-3 &c. Deg. 85-58 131-94 0-00 Deg. 119-32 42-36 265-30 Deg. 28-9841042 28-4397296 30-0000000 h. 4-1167 1-4895 8-8433 h. - 2-6272 +4-7266