185

α-i

Table showing the Rate of Secular Change at Seven Stations in the North Island.

Deduced value of secular variation of magnetic declination, + 03-1' per annum.

nc 'dilation. Station. Date. Inclination. Interval, Years. m . , ,-,, Rate of Change Total Change. , . e 5 per Annum. O I V / /lount Victoria ... 'etone )potiki lotorua (1899-96 (1902-69 (1899-97 11902-69 (1901-15 i 190300 1190113 (190311 11900-80 11903-21 (1900-63 11903-26 (1899-97 11903-27 65 26-88) 65 32-451 65 22-73) 65 26-671 62 06-18) 62 08-36 i 62 32-471 62 35-25) 62 28-05) 62 31-52 f 64 48-25) 64 55-43 i 65 23-47) 65 32 051 2-73 2-72 1-85 1-98 -f 5-57 + 2-04 + 3-94 +1-44 + 2-18 + 1-18 + 2-78 +1-41 'e Awamutu 2-41 + 3-47 + 1-4-4 jevin ... 2-63 + 7-18 + 2-73 lomes Island 3-30 + 8-58 + 2-61 Totals ... I , + 33-70 17-62 i Deduced value of secular variation of incli lation per nnum, -4- 1-91'. II. Horizontal Fc xe. Date. Horizontal Force: C.g.s. Units. Interval, Years. Rate of Change per Total Change. Annum : C.g.s. Units. Station. Mount Victoria Petone Opotiki Eotorua Te Awamutu ... Levin Somes Island... 11899-96 11902-69 (1899-97 11902-69 (1901-15 (1903-00 (1901-13 (190311 (1900-80 "11903-21 j 1900-63 11903-26 (1899-97 11903-27 0-24210) 0-24157) 0-24265) 0-24224! 0-26225) 0-26196) 0-25898) 0-25890) 0-26098 i 0-26035 i 0-24634) 0-24532) 0-24241) 0-24185) 2-73 2-72 1-85 1-98 - 0-00053 - 000041 - 0-00029 - 0-00008 - 0-00019 - 0-00018 - 0-00016 - 000004 2-41 - 0 00063 - 0-00026 2-63 - 000102 - 000039 3-30 - 000056 - 0-00017 Totals... 17-62 - 0-00352 Deduced value of secular variation of horizontal force, — 0-00020 c.g.s. units ] ler annum. III. Declination. Station. Date. Declination. TotaI chftn &? e - | Rate of Change per Annum. O I I I 1 SQQ-QR 1 x-, QQ.p. XT' O I ' Mount Victoria ... Petone Opotiki Eotorua . HV9-9h ii HH-H Hi. {1902-69 15 46-6 "[ 2 ' 73 + 08 ' 3 /I 000.07 1 ft QC.Ql (1899-97 15 35-8) 9 . 7g , 10 , J1902-69 15 48-2 f 2 72 + 12 4 .... (1901-15 14 44-3) , R , , nQ . tiki ... ... iQno.no 14 48-ni ib ° + Ud7 (1901-13 14 19-0) , QH . no . >rua 11903-11 14 21-1) 198 + 02 ' 1 (1899-96 11902-69 (1899-97 11902-69 (1901-15 (1903-00 (1901-13 11903-11 j 1900-80 11903-21 (1900-63 11903-26 (1899-97 U903-27 15 38-3 E.) 15 46-6 j 15 35-8) 15 48-2 f 14 44-3) 14 48-0) 14 19-OJ 14 21-1) 14 58-8] 15 08-2) 15 29-5) 15 37-6) 15 35-3} 15 45-71 + 30 + 4-6 + 2-0 + 1-0 Te Awamutu , , (1900-80 14 58-8] „ ,, , nQ . 11903-21 15 08-2) 2 41 + ° 9 ' 4 + 3-9 Levin ... (1900-63 15 29-5) „. CQ , nQ . ln 1903-96 1.5 37-61 Z M + 08 ' 1 + 31 • Somes Island t i ri (1899-97 15 35-3) o.on , ln a e» Island iQna.Q7 ui «.7 ! 3 30 + 10 4 + 3-2 Totals 17-62 + 54-4