360
MAGNETISM, TERRESTRIAL
Table II.—Recent Values of the Magnetic Elements and their Rate of Secular Change.
| Place. | Geographical position. | Absolute Values of Elements. | Secular change (mean per annum). | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Latitude. | Longitude. | Year. | D. | I. | H. | V. | Interval in years. |
D. | I. | H. | V. | |
| ° ′ | ° ′ | ° ′ | ° ′ | ′ | ′ | |||||||
| Pavlovsk | 59 41N | 30 29E | 1906 | 1 4.2E | 70 36.6N | .16528 | .46963 | 5 | −4.5 | +0.1 | − 6 | −14 |
| Sitka (Alaska) | 57 3N | 135 20W | 1906 | 30 3.3E | 74 41.7N | .15502 | .56646 | 4 | −3.0 | −1.6 | +18 | −38 |
| Ekatarinburg | 56 49N | 60 38E | 1906 | 10 31.0E | 70 49.5N | .17664 | .50796 | 5 | −4.5 | +1.7 | −23 | +18 |
| Rude Skov (Copenhagen) | 55 51N | 12 27E | 1908 | 9 43.3W | 68 45N | .17406 | .44759 | |||||
| Stonyhurst | 53 51N | 2 28W | 1909 | 17 28.6W | 68 42.8N | .17424 | .44722 | 5 | −5.9 | −1.1 | + 6 | −25 |
| Hamburg | 53 33N | 9 59E | 1903 | 11 10.2W | 67 23.5N | .18126 | .43527 | |||||
| Wilhelmshaven | 53 32N | 8 9E | 1909 | 11 46.8W | .18129 | 5 | −5.2 | − 7 | ||||
| Potsdam | 52 23N | 13 4E | 1909 | 9 10.6W | 66 20.0N | .18834 | .42971 | 5 | −5.8 | +0.1 | − 9 | −19 |
| Irkutsk | 52 16N | 104 16E | 1905 | 1 58.1E | 70 25.0N | .20011 | .56250 | 5 | +0.6 | +2.0 | −24 | +39 |
| de Bilt | 52 5N | 5 11E | 1907 | 13 19.0W | 66 49.9N | .18559 | .43368 | 5 | −4.7 | −0.6 | + 2 | −16 |
| Valencia | 51 56N | 10 15W | 1909 | 20 50.3W | 68 15.1N | .17877 | .44812 | 5 | −5.0 | −1.2 | + 7 | −25 |
| Kew | 51 28N | 0 19W | 1909 | 16 10.8W | 66 59.7N | .18506 | .43588 | 5 | −5.4 | −1.1 | + 2 | −35 |
| Greenwich | 51 28N | 0 0 | 1909 | 15 47.6W | 66 53.9N | .18526 | .43432 | 5 | −5.5 | −0.7 | + 1 | −20 |
| Uccle | 50 48N | 4 21E | 1908 | 13 36.7W | 66 1.6N | .19061 | .42867 | 4 | −5.3 | −0.8 | − 3 | −35 |
| Falmouth | 50 9N | 5 5W | 1909 | 17 48.4W | 66 30.6N | .18802 | .43266 | 5 | −4.7 | −1.4 | + 9 | −30 |
| Prague | 50 5N | 14 25E | 1908 | 8 20.9W | 5 | −6.5 | ||||||
| Cracow | 50 4N | 19 58E | 1909 | 5 35.1W | 64 18N | 3 | −7.3 | |||||
| St Helier | 49 12N | 2 5W | 1907 | 16 27.4W | 65 34.5N | 5 | −5.3 | −1.2 | ||||
| Val Joyeux | 48 49N | 2 1E | 1909 | 14 32.9W | 64 43.9N | .19727 | .41792 | 5 | −5.4 | −1.7 | + 1 | −51 |
| Vienna | 48 15N | 16 21E | 1898 | 8 24.1W | ||||||||
| Munich | 48 9N | 11 37E | 1906 | 9 59.5W | 63 10.0N | .20657 | .40835 | 5 | −4.8 | −1.3 | + 4 | −31 |
| O’Gyalla | 47 53N | 18 12E | 1909 | 6 43.9W | .21094 | 5 | −5.0 | −10 | ||||
| Odessa | 46 26N | 30 46E | 1899 | 4 36.7W | 62 18.2N | .21869 | .41660 | |||||
| Pola | 44 52N | 15 51E | 1908 | 8 43.2W | 60 6.8N | .22207 | .38640 | 5 | −5.5 | −0.6 | − 4 | −23 |
| Agincourt (Toronto) | 43 47N | 79 16W | 1906 | 5 45.3W | 74 35.6N | .16397 | .59502 | 4 | +3.4 | +0.9 | −23 | −24 |
| Nice | 43 43N | 7 16E | 1899 | 12 4.0W | 60 11.7N | .22390 | .39087 | |||||
| Toulouse | 43 37N | 1 28E | 1905 | 13 56.3W | 60 49.1N | .22025 | .39439 | 5 | −4.5 | −1.5 | + 2 | − 2 |
| Perpignan | 42 42N | 2 53E | 1907 | 13 4.4W | 7 | −4.7 | ||||||
| Tiflis | 41 43N | 44 48E | 1905 | 2 41.6E | 56 2.8N | .25451 | .37799 | 7 | −5.2 | +1.7 | −26 | + 2 |
| Capo di Monte | 40 52N | 14 15E | 1906 | 8 40.3W | 56 13.5N | 5 | −5.1 | −1.5 | ||||
| Madrid | 40 25N | 3 40W | 1901 | 15 35.6W | ||||||||
| Coimbra | 40 12N | 8 25W | 1908 | 16 46.2W | 58 57.3N | .22946 | .38120 | 5 | −4.6 | −2.9 | +17 | −45 |
| Baldwin (Kansas) | 38 47N | 95 10W | 1906 | 8 30.1E | 68 45.1N | .21807 | .56081 | 4 | −1.7 | +1.8 | −36 | − 8 |
| Cheltenham(Maryland) | 38 44N | 76 50W | 1906 | 5 22.0W | 70 27.3N | .20035 | .56436 | 4 | +3.8 | +1.2 | −38 | −45 |
| Lisbon | 38 43N | 9 9W | 1900 | 17 18.0W | 57 54.8N | .23516 | .37484 | |||||
| Athens | 37 58N | 21 23E | 1908 | 4 52.9W | 52 11.7N | .26197 | .33613 | 5 | −5.5 | |||
| San Fernando | 36 28N | 6 12W | 1908 | 15 25.6W | 54 48.4N | .24829 | .35206 | 5 | −4.6 | −2.8 | +26 | −24 |
| Tokyo | 35 41N | 139 45E | 1901 | 4 36.1W | 49 0.0N | .29954 | .34459 | |||||
| Zi-ka-wei | 31 12N | 121 26E | 1906 | 2 32.0W | 45 35.3N | .33040 | .33726 | 5 | +1.5 | −1.3 | +30 | + 6 |
| Dehra Dun | 30 19N | 78 3E | 1907 | 2 38.3E | 43 36.1N | .33324 | .31736 | 4 | +0.8 | +5.5 | −26 | +77 |
| Helwan | 29 52N | 31 21E | 1909 | 2 49.2W | 40 40.4N | .30031 | .25804 | 5 | −5.7 | +1.2 | − 6 | +13 |
| Havana | 23 8N | 82 25W | 1905 | 2 25.0E | 52 57.4N | .30531 | .40452 | |||||
| Barrackpore | 22 46N | 88 22E | 1907 | 1 9.9E | 30 30.2N | .37288 | .21967 | 3 | +4.2 | +3.4 | +21 | +62 |
| Hong-Kong | 22 18N | 114 10E | 1908 | 0 3.9E | 31 2.5N | .37047 | .22292 | 5 | +1.9 | −1.8 | +43 | − 1 |
| Honolulu | 21 19N | 158 4W | 1906 | 9 21.7E | 40 1.8N | .29220 | .24545 | 4 | −0.9 | −3.2 | −19 | −62 |
| Kolaba | 18 54N | 72 49E | 1905 | 0 14.0E | 21 58.5N | .37382 | .15084 | 5 | +2.1 | +7.2 | −11 | +86 |
| Alibagh | 18 39N | 72 52E | 1909 | 1 0.3E | 23 29.0N | .36845 | .16008 | 3 | +1.7 | +6.8 | −10 | +82 |
| Vieques (Porto Rico) | 18 9N | 65 26W | 1906 | 1 33.2W | 49 47.7N | .28927 | .34224 | 2 | +7.2 | +6.8 | −49 | +66 |
| Manila | 14 35N | 120 59E | 1904 | 0 51.4E | 16 0.2N | .38215 | .10960 | 5 | +0.1 | −3.9 | +47 | −34 |
| Kodaikanal | 10 14N | 77 28E | 1907 | 0 40.7W | 3 27.2N | .37431 | .02259 | 4 | +4.3 | +5.5 | +16 | +61 |
| Batavia | 6 11S | 106 49E | 1906 | 0 54.1E | 30 48.5S | .36708 | .21889 | 4 | +2.1 | −7.7 | − 2 | +110 |
| Dar es Salaam | 6 49S | 39 18E | 1903 | 7 35.2W | ||||||||
| Mauritius | 20 6S | 57 33E | 1908 | 9 14.3W | 53 44.9S | .23415 | .31932 | 5 | −0.3 | +2.9 | −53 | −131 |
| Rio de Janeiro | 22 55S | 43 11W | 1906 | 8 55.5W | 13 57.1S | .24772 | .06164 | 5 | +9.1 | −6.8 | −42 | +44 |
| Santiago (Chile) | 33 27S | 70 42W | 1906 | 14 18.7E | 30 11.8S | 3 | +6.1 | +9.9 | ||||
| Melbourne | 37 50S | 144 58E | 1901 | 8 26.7E | 67 25.0S | .23305 | .56024 | |||||
| Christchurch, N.Z. | 43 32S | 172 37E | 1903 | 16 18.4E | 67 42.3S | .22657 | .55259 | |||||
Table III.—Declination at London.
| Date. | Declination. | Date. | Declination. | Date. | Declination. |
|---|---|---|---|---|---|
| ° ′ | ° ′ | ° ′ | |||
| 1580 | 11 15E | 1773 | 21 9W | 1860 | 21 38.9W |
| 1622 | 6 0 | 1787 | 23 19 | 1865 | 20 58.7 |
| 1634 | 4 6 | 1795 | 23 57 | 1870 | 20 18.3 |
| 1657 | 0 0 | 1802 | 24 6 | 1875 | 19 35.6 |
| 1665 | 1 22W | 1805 | 24 8 | 1880 | 18 52.1 |
| 1672 | 2 30 | 1817 | 24 36 | 1885 | 18 19.2 |
| 1692 | 6 0 | 1818 | 24 38 | 1890 | 17 50.6 |
| 1723 | 14 17 | 1819 | 24 36 | 1895 | 17 16.8 |
| 1748 | 17 40 | 1820 | 24 34 | 1900 | 16 52.7 |
| 1905 | 16 32.9 |
§ 12. Table VII. gives particulars of the secular change of horizontal force and northerly inclination at London. Prior to the middle of the 19th century information as to the value of H is of uncertain value. The earlier inclination data[1] are due to Norman, Gilbert, Bond, Graham, Heberden and Gilpin. The data from 1857 onwards, both for H and I, refer to Kew. “London” is rather a vague term, but the differences between the values of H and I at Kew and Greenwich—in the extreme west and east—are almost nil. For some time after its discovery by Robert Norman inclination at London increased. The earlier observations are not sufficient to admit of the date of the maximum inclination or its absolute value being determined with precision. Probably the date was near 1723. This view is supported by the fact that at Paris the inclination fell from 72° 15′ in 1754 to 71° 48′ in 1780. The
- ↑ (1) p. 166.
