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21
19
19
20
19

30
47
53

31

27

29

39 45

have the same relative position. From a comparison These results have received a very remarkable of the observations made at different times, he found confirmation from the observations both of the vathat these poles had a constant motion.

riations and dip made during the voyages of Capt. The motion of both the northern poles is from Ross and Capt. Parry. In August 1819, Capt. ParW. to E. obliquely, and of both the southern ones ry was north of the magnetic pole, and from his also obliquely from E. to W. With regard to the measure of the dip, viz. 88° 37', on the 11th Sepvelocity of their motion, Prof. Hansteen acknow. tember 1819, the expedition must have been about 30 ledges that the observations are not sufficiently nu. north of the magnetic pole; but they were then in merous, but he has obtained the following results: 74° 27', consequently the pole must have been in 71°

N is the strongest pole in the north hemisphere, 27', or its distance from the pole of the globe must and its revolution round the north pole of the earth have been 18° 33'. . We may therefore conclude, is performed in 1740 years.

that the position of the strongest pole N in the S is the strongest pole in the south hemisphere, northern hemisphere is well determined. and its revolution round the south pole of the earth 2. On the Position of S. the strongest Magnetic Pole is performed in 4609 years.

in the Southern Hemisphere, south of New Holland. n is the weakest pole in the north hemisphere, and its revolution is performed in 860 years.

By combining the observations made by Captain s is the weakest pole in the south hemisphere, neaux in 1773, Professor Hansteen has obtained the

Cook in 1773 and 1777, and those made by Fourand its revolution is performed in 1304 years.

following results, from which two of the most disPOLE N, POLE S,

POLE 8, cordant are rejected: Strongest Pole in Strongest Pole in Weakest Pole in Weakest Pole in

Distance of the Pole S from

Lon. East of North Hemisphere. South Hemisphere North Hemisphere. South Hemisphere.

the Polc of the Earth.

Greenwich. 20° 26'

133° 7' Year, Distance Long Distance Long Distance Long Distance Long.

East from the West from the from the East from the

20 58 West

135 12 North from South from North from

132 47
South from
Pole. Green Pole. Green Pole. Green Pole. Green-

136
wich.
wich.
wich.
wich.

136 25

138 1800, 20°

8 7' 93° 33' 20° 53' 134°

138 11 4° 35' 131° 43' 12° 10' 130° 28'

21 1810,20 15 91 28 21 1 133 21 4 42 135 54 11

134 21

57 133 14 1820, 20 22 189 24 21 8 132 35 4 48 140 6 11 44 135 59

Mean, 20° 33.5

Mean, 136' 15'.4 1830,20 30 87 19 21 16 131 47 4 54 144 17 11 31 137 45 But, in the year 1642, Prof. Hansteen found these po

1840, 20 38 185 15 21 23 131 1 5 0 148 28 11 19 140 31 sitions, from the observations of Jansen Tasman, to be, 1850,20 46 183 10 21 31 130 14 5 0 152 40 11 6 143 16

Distance from Pole,

19° 55'
Lon. East of Greenwich,

116 59
Since this table was computed, Professor Han-
steen has obtained many new sets of magnetical ob-

Hence, in 131 years, the pole S has moved west-
servations, and particularly those which have been ward 10° 14' or 4'.69 per annum.
made during the British Voyages of discovery to

Its period of complete revolution will be 4505 the Arctic Regions. These he has diligently com

years. pared, and he has thus obtained new determinations 3. On the Position of n, the weakest Magnetic Pole of the position and times of revolution of the mag

in the North Hemisphere in Siberia. netic poles of the earth. The results of these we By combining a number of observations made in shall now lay before our readers in a very abbre. 1805 at Tobolsk, Tara, and Udinsk in Siberia, Proviated, but, we trust, intelligible and useful form. fessor Hansteen obtained the following results:

Distance of n from Lon. East from 1. On the Position, &c. of N. the strongest Magnetic

the Pole of the Earth. Greenwich. Pole in North America.

4' 27

116'27' By combining four observations on the declination

51 of the needle, made on board his Majesty's sloop Bra

Mean, 438' 30" Mean, 116° 19'
zen in Hudson's Bay, in 1813, and which Prof. Han But, in 1770, Professor Hansteen found the posi-
steen inspected in the Marine Chart office at the Ado tions of this pole to be,
miralty in London, he obtained the following results:

Distance from Pole in 1770, 4° 14'
Distance of the Pole N from

91 29 30" Lon. West of

Lon. East froin Greenwich, the Pole of the Earth.

Greenwich.

Hence in 35 years, the pole n has moved 14° 35' 1813, 21° 44'

91° 35'

30", or 35.'128 per annum. 23 40

92 18

Hence it. appears, that the magnetic pole n has a 22 9

93 22

motion from west to east, and that its period of 23 47

9 21

complete revolution is 860 years. Mean, 22° 50'

Mean, 92 24' By placing this result beside former determina- 4. On the position of s, the weakest Magnetic Pole in tions, we have,

the Southern Hemisphere south of Terra del Fuego. Distance of N. Lon. West of

By combining the observations made by Captain from Pole.

Greenwich.

Cook and Fourneaux in 1774, Professor Hansteen 1730, 19° 15'

188 6 1769, 1943

100 2

has obtained the following results:
1813, 22 50

92 24
Distance of the Pole s from

Lon. TV'est from
Hence we have,

the Pole of the Earth.

Greenwich,
Motion of the Pole N.
Annual

12° 36'

122° 5%
to the East.
Motion.

12 44

122 21
From 1730 to 1769,
12.44

13 15

120 42
From 1769 to 1813,
10.41

12 46

124 7 12 47

123 48 Mean motion,

11'.425 Period of complete revolution, 1890 years.

Mean, 12° 431'

Mean, 123° 17

4

50

115

.

0

19 19

30
15
30

30
14

7
8

1675

1798

69° 26' 68 32

72 15

1780

But, in 1676, from observations mentioned by sea, the variation was easterly in 1605. The following Halley in the Phil. Trans. No. 48, Professor Han- are the variations since the time of Vasco de Gama: steen found the position of this pole to be,

Years.
Declination of

Declination of

Years.
Distance from the Pole in 1670,

15° 53
the Needle.

the Needle.
1605

94 33 Lon. West from Greenwich,

9' 30' EAST. 1724 16° 27' WEST. 1609 12 WEST

1752

0 Hence, in 104 years, the pole s has moved west

1614 1

1768 ward 28° 43' or 16'.57 annually; and we have its 1667

1775 21 period of complete revolution, 1303 years.

1791 25 40 MAXIMUM. 1702 12 50

1804
25

4
From these determinations, it appears that the
two magnetic poles in the northern hemisphere, N and

Now, in 1605, the South American pole s was n, move eastward, while the two S, s, in the southern 761° west of Greenwich, nearly south of Terra del hemisphere move westward.

Fuego, and the New Holland pole S was about 150°

east of Greenwich; the pole & was, consequently, As the poles N and S are nearly about the same distance from the terrestrial poles, and, therefore, much nearer the Cape than it is now, while the other almost diametrically opposite, and as they are alsó pole S was more remote from it. The effect of s, theremuch stronger than n and s, Professor Hansteen fore, was greater, and of S less than at present, so properly assumes, that N and S are the terminating that the south pole of the needle moved more to. points of one magnetic axis, and n and s those of the wards the west, and its north pole more towards the

east. other axis. Therefore, says he, these two magne

But as s went farther off, and S approached tic axes cross without intersecting one another, or

the Cape, the south pole of the needle turned more passing through the centre of the earth. The cen and more towards S, so that the declination became ire of both lie much nearer the surface in the South westerly. Sea than in our hemisphere.

To obtain an example from the dip, Professor In answer to the question which naturally arises Hansteen gives the following observations at Paris: respecting the cause of these remarkable phenome

Years.
Dip.
Years.

Dip. 1671

71° 0 na, Professor Hansteen makes the following obser

1754

1814 vation: It is possible that the illumination and

71 40

1829

67 41 heating of the earth, during one revolution about

Though the dip thus diminished at Paris, yet it its axis, may produce a magnetic tension, as well

increased in Eastern Siberia and Kamtschatka. as it produces the electrical phenomena, and that

Both these changes are the results of the motion of the change of position in the magnetic axis may be

the Siberian pole n towards the east, in which it is explained from a change of position in the earth's

removed from Europe, and approaches to Kamt. axis to its orbit.

schatka. In all s. America the dip decreases in Professor Hansteen next proceeds to show how the changes in the variation and dip of the needle pole s towards the west.

consequence of the motion of the Terra del Fuego may be explained by the motion of the magnetic

In order to discover the nature of the forces by poles; and he begins with the observations made at which the phenomena of terrestial magnetism are Paris, where the variation was as follows:

produced, Professor Hansteen resolved to deterDeclination of

Declination of
Years.
Years.

mine the intensity of magnetism in different parts of the Needle.

the Needle.
7° 0' EAST.

1667
15 WEST.

the earth's surface, and then to ascertain the form 31)

of the isodynamical magnetical lines, or those of 1590 11 30 MAXIMUM.

equal intensity. He accordingly had a magnetic 1603

needle of a cylindrical form constructed with great 1610 1800 22

This needle he entrusted to various philoso. 1659

1807

phers, who counted the time in which three hun1664

1914

54 MAXIMUM. dred horizontal oscillations were performed, in va1666 0 0 No VARIATION. 1829

12

rious parts of Norway, Sweden, Denmark, PrusNow it appears that, in 1580, the Siberian pole sia, Holland, France, England, and Scotland. The n was about 40° east of Greenwich, or to the north greater number of these were made by Professor of the White Sea, while the North American pole Hansteen himself, many of them by M. Naumann, N was about 136° west of Greenwich, or about 30° several by M. Erichsen, and a considerable number east of Behring's Straits. The pole n, therefore, by Professor Oersted of Copenhagen, when he was lay nearer Europe than now, and the pole N was travelling in England in 1823. Those which were more remote. Hence the former exercised a pre made by this last philosopher in Edinburgh on the dominant action, and the needle turned towards the 4th of July, 1823, and at which we had the pleasure east. In the mean time, the pole n withdrew itself of assisting, were performed in the field behind towards the Siberian Ocean, and as N approached Coates Crescent, and nearly at the intersection of Europe, its action increased, and the needle turned Walker Street and Melville Street. These possess westward till 1814, when it reached its greatest de considerable interest, as being the most westerly clination, and since that time it is evidently return of all that were then made. ing eastward. On the very same principles we see In order to determine the intensity of the mag. the reason why the eastern declination was less be netic force throughout Scotland, Dr. Brewster orfore 1580.

dered, for the Royal Society of Edinburgh, one of The variations of the needle in the Southern hem the instruments used by Professor Hansteen. isphere are explicable in the same way. At the Cape When this instrument arrived from Christiania, of Good Hope, and in different bays of the adjoining where it was executed under Professor Hansteen's

1541 1550

8

0

1670 1680 1683 1700


1
2
3
7

1630

8 4 3 2

40
50
40
12
34

45 30 0 0 40

care.

22
22
22

own eye, and furnished with one of his own needles, The following table exhibits the results of the
Dr. Brewster put it into the hands of Mr. James observations, made by Professor Hansteen and his
Dunlop, who, with his usual zeal for the interests friends, the first and second columns containing the
of science, performed a tour through Scotland, in latitude of the place of observation, and its longi.
1829, and made a most important series of mag- tude from Ferro; and the third the number of se.
netical observations. They, having been commu conds in which 300 oscillations are performed by
nicated to the Royal Society of Edinburgh, will be the suspended needle.
speedily published.

[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed]

The following additional observations have been 3. The line of 800 passes about the fifth of a desent to us by Professor Hansteen:

gree north of York, Sporring in Jutland, and FalCarlscrona,

735

kenberg in Sweden. Breslau, ,

741

4. The line of 820 passes through Edinburgh, Stockholm,

815

and a little to the south of Christiansand in NorHernosand,

850

way, and Carlstadt in Sweden. These various results have been laid down on a 5. The line of 865 passes through Hirdal in map by Professor Hansteen; but as they occupy Norway. only a small part of Europe, we do not think it As the lines are almost equi-distant, and nearly necessary to copy his chart. Any of our readers, parallel, all the intermediate ones may be readily however, may easily lay down, upon a map of Eu- inserted. rope, the lines of equal magnetic intensity, either Professor Hansteen has added the following very from the above tables, or more simply by the fol- interesting table, containing the observed dip of lowing directions:

the needle, and the computed magnetic intensity in 1. The line of 750, or the line in which the 750 various parts of the world, that of the equator beseconds are required for the performance of 300 ing unity or 1.0000. A similar table was printed oscillations, passes one-fourth of a degree to the in Professor Hansteen's paper, in Poggendorff's south of Paris and Rheims, and one third of a de- Annalen der Physik, but the column of intensity gree to the south of Gotha and Gaslin. *

had been wrong computed for all the places in the 2. The line of 775 passes about one-third of a north of Europe, and we are happy to be able, degree south of London, and through Amsterdam through Professor Hansteen's kindness, to present and Lubeck.

our readers with a corrected copy.

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[graphic]

Inten-
Inten-

IntenPlaces of Observation. Dip.

sity.
Places of Observation. Dip. sity,

Places of Observation. Dip. sity.
South.
North.

North.
Port du Nord
175° 50' (1.5773|Nimes
65° 23' 1.2938 Gottenburg

71° 58' 1.3826 Port du Sud 170 48 1.6133 Mailand

65 40 1.3121|Altorp

72 14 1.3891 Surrobaya in Java 25 40 0.9348 Montpellier

65 53 1.3482 Korset

2172 24 1.3735 Amboyna 20 37 0.9532||Airola 65 55 1.3090 Quistrum

72 27 1.4070 Lima 9 59 1.0773 Turin 66 3 1.3364 Skieberg

72 29 1-3725 Magnetic Equator in Peru 0 0 1.0000 Medina del Campo

9 1.2938 Elleoen

172 38 1.3340 North. Lans le Bourg Mont Cenis 66 9 1.3227 Helgerone

72 39 1.3980 Tompenda зегна 3 11 1.0191||Como 166 12 11.3104 Soner

172 41 11.3835 Loxa 5 24 1.0095||St. Michel 66 12 1.3488 Christiania

72 34 1.4195 Cuenca 8 43 1.0286||Lyons 66 14 1.3.334 Ryenberg

72 45 1.4208 Quito 13 22 1.2675|St. Gothardt 66 22 1.3138 Bogstad

72 34 1.4378 St. Antonio (14 25 1.0871 Mont Cenis 66 22 1.3441 Bogstadberg

73 13 1.4195 St. Carlos PESTE 20 47 1.0480||Ursernes 166 42 |1.3069 Nasoden

173 2 1.4517 Popayan 2 20 53 1.1170||Altorf

66 53 (1.3228] Bärum

72 44 1.3902 Santa Fe de Bogota 24 16 1.1473 Atlantic Sea,

Bolkesjoe

73 15 1-4053 Javita 24 19 1.0675 37° 14' n. 3° 30' 0" 67 30 1.3155 Ingolfsland

73 19 1.4159 Esmeralda

25 58 1.0577
38 52 — 3 40 67 40 (1.3155 Norsteboe

73 33 1.4136 Carichana 30 24 1.1575 Madrid 67 41 1.2938 Drammen

73 37 1.3771 St. Thomas Dit is 35 6 1.1070 Tübingen

4 11.3569 Maursäter

73 44 |1.4656 Carthagena £$! Mi 35 15 1.2938||Atlantic Sea,

Ullensvang

173 44 1.4260 Cumana ***** |3947 1.1779|38° 52' n. 3° 40' 0" 68 11 1.3155 Gran

173 45 1.4221 Mexico 42 10 1.3155|Ferrol

68 32 1.2617 Kongsberg Atlantic Sea,

27173 47 1.4144 Paris 69 12 1.3482 Tomlevold

73 50 1.4246 B.20° 46' n.L.41.26' w.F. 41 46 (1.1779 Gottingen

69 29 1.3485 Bekkervig

73 58 1.4114 11 0 - 44 32 41 57 1.2617||Berlin

169 53 1.3703 Vang

173 59 1.4308 12 34 33 14 - 45 8 1.2300||Carolath

68 21 1.3509 Bergen

3 1.4220 14 20 · 28 3 52 55 1.2830 Berlin

68 50 (1.3533 Moe

512 174

3 1.4254 20 8 8 34 |56 42 1.2510 Danzig

69 44 11.3737 Mauristuen

74 4 1.40581 21 36 5 39 47 49 1.2617||London

69 57 1.3697 Leierdal

74

6 1.4190 25 15 60 18 ]1.2830 Ystad 70 13 1.3742 Slidre

74 34 1.4543 Portici 160 5 1.2883 Schleswig

170 36 1.3814 Brassa

ĐẾN 5022 174 21 1.4471 Naples TO 61 35 1.2745 Copenhagen

70 36 11.3672) Davis Straits, Romeu web 32161 57 1.2642|Odense

170 50 11.3650 68° 22' n. 36° 10' w. 83 831.6365 |Vesuv. Crater

62
01.1933 Helsinburg-

70 52 (1.3782 Hare island,
St. Cruz, Teneriffe
62 25 1.2723 Kolding

70 53 1.3846 70° 26' n. 37° 12' w.82 49 1.6406 Valencia 63 38 1.2405 Soroe

170 57 1.3842 Baffin's Bay, Florence 63 51 1.2782 Freidrichsburg stis! 170 59 1 4028

75° 5' n. 42° 43' w.84 25 1.6169 Atlantic Sea, ins;

Aarhuus

171 13 11 3838||

75 51 - 45 2684 4451.6410 32° 16' n. 2° 52' w. 64 21 |1.2938 Aalborg 57564

71 27 1.3660 76 45 58 20 186 9 1.7052 64 37 1.3482 |Odensala

71 39 11.3666

76 0 - 60 41 86 0 1.6885 Marseilles 165 10 (1.2938||Friedrichshaven

171 48 1.3842 70 35 49 15 84 39 11.6837

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• The line of 740, of which only one point has been determined, passes through Breslau. VOL. XVIII.-PART I.

Y.

The following table shows the law of variation The next curve, or that in which the same needle from the equator to the pole.

performs the same number of oscillations in 278 Magnetic Magnetic

seconds. This curve goes round both the American dip. intensity.

and the Asiatic poles, including both within its arc. 1.0

It passes to the N.W. of Melville Island, and to the 24 1.1

N. E. of some stations on the west coast of Green45 1.2

land, and it cuts the American coast between the 64 1.3

Havana and New York. The same curve has been 73 1.4

traced in Asia, by Dr. Erman, who accompanied 765 1.5

Hansteen from the embouchure of the Oby, in Lat. 81 1.6

68°, and E. Lon. 70°, following the direction of the 86 1.7

river Mina as far as Lat. 60° N. Here the curve

gradually bends to the east, passes between ToThis valuable table of results received many ad- bolsk and Narym, and was found again by M. Handitions from the experiments by Captain Sabine, in steen at Kainsk, a few degrees to the south of Lake the two arctic voyages of discovery performed in Baikal. 1818, 1819, and 1820, and in a voyage performed The third curve, or that of 287 seconds, is drawn in 1822, to the equatorial shores of the Atlantic, from observations made at the Havana, at the Penduand to some of the islands of that and the Caribbean lum Isles, on the east coast of Greenland, in Lat. 74° sea, and lastly, in a fourth voyage, made in 1823, 5' and between Spitzbergen and Hammerfest, near to Greenland, Spitzbergen, and Norway. But not the North Cape. According to professor Hansteen, withstanding these valuable accessions, professor this curve enters the continent of Europe between Hansteen was desirous of performing a journey into Archangel and Nova Zembla; and he crossed it in Siberia, for the purpose of establishing, by actuał going from Moscow to Tobolsk, at 56° and 57° of observation, the existence of a weaker pole in the East Lon. and 57o and 58° of North Lat. north of Asia, and of extending the isodynamical The fourth curve, or that of 297 seconds, passes lines of Europe as far as possible to the east. From near Jamaica, where the oscillations were 294 se. this journey he has just returned, after the success- conds, passes through the north part of Britain, ful execution of his most sanguine wishes. We and enters Norway to the south of Bergen. It wait with anxiety for the publication of his obser. passes between Stockholm and Tornea, and thence vations; but we are enabled in the mean time to by St. Petersburg and Moscow. present our readers with a small chart of the north These four curves are the only ones that lay ern hemisphere, as drawn by Captain Sabine from within the sphere of observation of professor Hanthe

observations communicated to him by professor steen. The rest of the curves in the map were laid Hansteen, combined with his own and with those down by Captain Sabine, principally from his own given in the preceding table.

observations and those Humboldt. In this map, the full-drawn black lines pass Although the preceding investigations go far to through the stations where the magnetic intensity point out the form of the isodynamical magnetic was observed to be equal, and the dotted parts of lines, yet much remains to be done before the the same lines indicate the presumed direction of blanks are filled up, and the lines traced round the the curve in those regions where observations have poles of the southern hemisphere. not yet been made. The portions round the Ameri. The most important and the most difficult part can pole are drawn principally from Captain Sa- of the problem which still remains, is to ascertain bine's observations, and the prolongation of the the velocity with which these poles revolve; and same portions of the curves round the Asiatic pole we entertain sanguine hopes that, in consequence are drawn from the recent observations of Han- of the recommendation of Baron Humboldt," and steen. The American pole is situated nearly in 60° the zeal of the Academy of Sciences of St. Peters. of North Lat. and 80° of Lon. West of Greenwich. burg, a regular system of observation will be im. The Asiatic pole is situated in 102° of East Lon., mediately set on foot by the Russian government, (180° distant from the American one) and in 60° of to obtain an early solution of this great scientific North Lat.

question. The empire of Russia is actually tra. The first, or most porthern curve, is that in which versed by two lines of the variation. One of these a needle which performed a given number of oscil. lines, according to the recent observations of Hanlations in 300 seconds in London, performed only steen and Erman, passes between Mourum and 269 at all places under the curve. Round the Asia. Nijni-Novgorod, and the second some degrees to tic pole this curve will be seen to contain a smaller the east of Irkutsk, between Parchiuskaia and Tor. space than round the American pole, which proves binsk. It is proposed to determine with great prethe inferior activity of that pole. M. Hansteen cision every ten years the exact position of these traced the south part of this curve below 60° of two lines. Petersburg, Moscow, and Kasan are latitude from the river Jenisei to the west, as far situated near the first line of no variation, which as the 115th degree of Lon.; that is, 250 beyond traverses Russia in Europe. Kiachta and Verkhnéthe Jenisei, and to the Lat. of 60°, where it takes a Oudinsk present advantages for the second line, direction almost from S. to N.

which passes through Siberia. In the space of

• See Dr, Brewster's Journal of Science, No. IV. New Series, April 1830.

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