C—la

Table C. Mean Values of the Harmonic Constants for Use in preparing the Tide-tables.

An analysis of one year's observations of the observed times of the swinging of the light-ship at the Bluff to the flood and ebb tide was performed, with the results that the light-ship swings to the flood 27m. after low water, and to the ebb 21m. after high water, respectively, at Bluff Harbour Wharf. These values are in agreement with the hitherto published results in the "New Zealand Nautical Almanac." A comparison of the predicted times of high water and low water as published in the tide-tables for the year 1921 with the actual values obtained from the automatic tide-gauge is given in Tables ] to 3 in the report of Mr. E. J. Williams, Tide-computer (appended) for the ports of Auckland, Wellington, Bluff, and Westport. The error in the times and heights of high and low water are of the same order as those shown in all tide-tables computed by the method of harmonic analysis, and the tide-tables are considered satisfactory for the purposes of navigation. Two new tide-gauges, on the same pattern as that operating at Wellington, were manufactured locally by Messrs. Littlejohn and Son. One is installed at Lyttelton and the other at Dunedin, replacing the very old and unreliable gauges hitherto in use at these ports The new gauges are performing satisfactorily. The mean high-water mark has been determined from the record of the year 1921 for the following places. The readings on the tide-ga-uges of the mean high-water marks arc : Auckland, 9-73 ft. ; Wellington, 4-64 ft. ; Bluff, 8-27 ft. ; Westport, 8-60 ft. These readings are for practical use in defining high-water marks along the foreshore. The tide-tables for the year 1924 were received in Wellington from the Director, National Physical Laboratory, Toddington, on the 20th September, 1922. Advice was received from the Hydrographer to the Admiralty at the end. of May, 1922, that the Tidal Department at the Laboratory was closed and the tide-predicting machine transferred to India. The Director of the Laboratory had, however, run off the curves to enable him to supply predictions for 1924 and 1925. The Government then authorized the Hydrographer to make arrangements for the prediction of the tide-tables for six New Zealand ports for 1926 and onward. The exchange of the New Zealand tide-tables with other responsible national authority requiring them for inclusion in published tide-tables, in accordance with the recommendations of the International Hydrographic Conference, 1919, is contemplated by the Hydrographer. The New Zealand predictions have therefore been placed at his disposal for exchange purposes, which will be of great advantage to the Dominion in having the New Zealand tide-tables published abroad, and will lead to the inclusion of predictions from more foreign parts in the Admiralty Tide-tables.

4

Tide Symbol. Auc] kland. 5-74 ft. HI lull. 5 38 ft. Duj ledin. 5-23 ft. Lyttelton. A„=3-20ft. Wellington. West A 0 =2-93ft. A„=6 J. K. H. iport. >-00 ft. Ii. K. H. K. H. K. H. K. H. K. Short Period. SI S2 S4 Ft. 0-010 0-595 0-020 O 1735 20,5-12 334-01 Ft. 0-009 0-503 0-010 94-60 49-35 225-12 Ft. 0-015 0-215 0-007 O 14-41 129-50 318-52 Ft. 0-035 0-179 0-009 O 31-91 143-04 202-78 Ft. O-O03 0-100 O-OOl ft. ° Ft. 003 331-00 0-011 100 334-84 0-970 004 207-87 0-008 Q 69-61 332-02 19-18 SO Ml iM2 0-003 0-011 3-805 55-73 144-69 204-90 0-006 0-013 2-859 107-05 119-06 35-81 0 003 0-010 2-485 115-92 108-52 122-39 0-015 0-010 2-879 344-95 99-40 125-03 O-005 O-0O7 1-000 005 310-03 0-006 007 0-39 0016 000 137-23 3-754 329-28 80-00 304-17 MS Ml M6 0-038 0-108 0-024 199-10 128-64 309-52 0-010 0-092 0-087 272-60 226-85 79-41 0-016 0-261 0-072 262-98 177-75 357-87 0-016 0-010 0-022 112-80 80-19 68-96 0-021 0-1)37 0-014 021 175-36 0-021 037 25801 0-060 011 90-98 0-026 210-07 43-83 36-73 01 Kl K2 0-055 0-235 0-142 140-10 108-27 252-93 0-114 0 05!) 0-132 73-47 116-06 47-40 0 088 0-074 0-091 72-39 90-24 122-50 0-088 0-148 0 054 61-46 82-58 102-88 0-105 0-084 0-045 105 35-34 0-093 084 81-79 0-074 045 351-44 0-264 17-04 184-13 329-53 PI ,11 Ql 0-075 0-0)5 0-012 165-28 203-80 05-42 0-023 0-000 0-028 105-71 218-5! 42-72 0-023 0-004 0-028 ill -68 78-86 70-62 0-051 0-007 0-021 112-04 110-39 43-38 0-032 0-007 0-037 032 74-67 0-024 007 141-00 0-014 037 24-64 0-037 130-32 232-09 31-52 L2 N2 v2 0-171 0-793 0-190 202-92 172-38 i»7-:m O-KHi 0-647 0-135 32-24 16-85 59-31 0-155 0-537 0-099 102-59 104-34 114-97 0-088 0-003 0-148 148-45 95-31 122-05 0-048 0-405 0-122 048 124-43 0-089 405 101-66 0-753 122 130-26 0-179 280-34 288-29 322-85 T2 (MS)4 0-103 0-067 0-180 172-63 293-47 195-00 0-062 0-021 0-080 5-86 94-47 1-53 0-029 0-017 0-108 46-38 231-08 140-91 0-091 0-030 0-102 59-29 219-85 123-98 0-072 0-036 0-035 072 90-40 0-126 036 283-24 0-048 035 134-53 0103 283-59 1 I -08 297-37 (2SM)2 R2 0-004 0-023 303-96 214-72 0-043 0-014 121-14 121-64 0-046 0-014 8-44 198-62 0-066 0-013 25-99 130-12 0-033 0-015 033 352-71 0-079 015 132-60 0-0-41 202-28 236-31 Long Period. Mm Mf MSf 0-083 0-044 0-054 184-66 252-09 181 -63 0-048 0-000 0-064 262-34 180-11 324-28 0-056 0-068 0-089 69-33 184-30 137-04 0-048 0-063 0-129 137-29 183-39 156-38 0-065 0-043 0-083 065 303-88 0-028 013 175-37 0-046 083 71-66 0-066 150-48 330-87 132-03 Sa Ssa 0-223 0-065 46-05 113-05 0-007 0-110 41-93 90-56 0-135 0-073 267-26 104-27 0-097 0-085 246-56 139-91 0-088 0-080 088 301-59 0-101 080 153-27 0-124 100-39 10027