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extensive in Africa, and more heated, the ascending current is, therefore, more powerful, and thus the air from over the cold current is attracted with more force.

The mean direction of the wind in the tropical part of the Atlantic is as follows:

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Zone 14. 600-800 W. S. 88° E. .77 N. 73° E. 1.51

14. 40 -50 W. N. 58 E. 1.75 N. 63 E. 1.55
14. 15 -25 W. N. 27 E. 1.79 N. 51 E. ..58
15. 60 -80 W. N. 89 E. .84 | N. 66 E. 1.80
15. 45 -50 W. N. 60 E. 1.77 N. 64 E. 1.73
15. 15 -25 W. N. 42 E. !.91 N. 31 E. 1.76
16. 45 -50 W. N. 55 E..90 N. 49 E. .86
16. 30 -35 W. N. 72 E. .55 N. 68 E. 1.87
16. 15 -25 W. N. 10 E. 1.18 N. 37 E. .77
17. 45 -50 W. N. 66 E. 1.56 N. 50 E. 1.91
17. 30 -35 W. S. 49 E. 1.05 N. 65 E. 1.38
17. 10 -20 W. S. 4 W..88 N. 9 W.1.31
18. 40 -55 W. S. 55 E. 1.82 N. 73 E. .74
18. 30 -35 W. S. 62 E. 1.70 N. 87 E. 1.69
18. 10 -20 W. S. 13 E. 1.83 S. 29 E. .34

Zone 23. 40°-45° W. N. 66° E. 1.36 | N. 58° E. 1.44

23. 20 -25 W. S. 65 E. 1.46 N. 85 E. 1.55 23. 0 - 5 E. S. 28 E. 1.65 S. 29 E. 1.63 22. 35 -39 W. S. 61 E. .67 N. 72 E. .72 22. 10 -20 W. S. 55 E. .79 S. 61 E. .80 22. 0 -12 E. S. 26 E. .84 S. 35 E. .96 21. 35 -39 E. s. 50 E. .79 S. 87 E. 1.83 21. 15 -25 W. S. 48 E. 1.92 S. 84o E. 1.98 21. 5 W. 13 E. S. 6 E. 1.63 S. 45 E. 1.100 20. 33 -35 W. S. 46 E 1.89 S. 75 E. 1.83 20. 15 -20 W. S. 47 E. .96 S. 45 E. 1.96 20. 15 W. 10 E. S. 11 E. 1.68 S. 11 W..59 19. 35 -45 W. S. 48 E. S. 62 E. 1.88 19. 20 -25 W. S. 43 E. .92 S. 35 E. 1.89 19. 15 W. 11 E. S. 6 E. 1.73 S. 16 W..67

(See also Plates 5, 6, and 14.)

This table is so arranged as to show the corresponding latitudes north and south opposite to one another. It will be seen how much more regular are the southern trades, especially between 0°-15°.

In the northern hemisphere the trades are well established between 10°-15° N. in the middle and western part of the ocean ; while near the African coast the winds are very variable, or better to say this latitude is divided in summer between the N. E. trade and the S. W. monsoon. In the corresponding latitude south, the S. E. trade is blowing regularly the whole year.

In latitude 50-10° N. the S. E. trade is already established in the middle of the ocean from June to August and the African monsoon in full force further east. In the corresponding latitude in the southern hemisphere the trade is very regular. It is also blowing between 0°-5° N. with the exception of the months from December to February, when the mean direction is E. N. E. in the western part of the ocean, probably owing to the heating of a part of S. America, towards which the air is drawn from the ocean. (See also Map, Plate 6.)

The more easterly direction of the trades in the western part of the ocean is well marked, especially as concerns the S. E. trade. It is probably due to the rotation of the earth, which gives the winds more easting the further they advance.

There is no doubt that the winds of the Atlantic which blow near the coasts of America have traversed a great part of the ocean, and thus acquired more easting. As to the winds which blow in the eastern part of the ocean, they do not come from so far. The African continent rather attracts the winds than otherwise. It has before been shown that from 5° N. to 20° S. southwesterly winds blow the whole year on the ocean near the coast of Africa, as exhibited on Plate 7. Thus the trade which blows further to the west cannot come from Africa. It originates on the Atlantic Ocean itself, over the cold antarctic current flowing at some distance from the African coast.

Barometric observations are numerous on the Atlantic Ocean, and are important as giving us the key to the winds. (See Plate 14.) Unfortunately their tabulation and reduction is not all that can be desired. They are calculated without regard to longitude, and from 5° to 5° of latitude only. Thus we do not know the difference of pressure in the eastern and western parts of the ocean, although it must be great, especially in latitude from 20° to 35° N. and S. as shown by the great difference in the polar limits of the trades.

The Meteorological Institute of the Netherlands has undertaken the calculation of the barometric means of the Atlantic Ocean for every degree of latitude, distinguishing also, in the southern hemisphere, the outward and homeward voyages. This would give two sets of figures, one for the eastern and one for the middle part of the ocean, as the ships going to the East Indies take a course more to the westward, while on returning they go nearer to the coast of Africa. This expected publication will shed light on many obscure problems.

The most complete barometrical table for the Atlantic we now possess is published in the Pilot Charts. It is calculated from 5° to 5o, for every month. I have calculated from it the pressure of the two contrasting seasons, and have given in the following table the pressure observed on some islands and coast stations reduced to sea-level. (See also Plate 14.) The mean pressure is at 32° Fahr.

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32° 38' N. 16° 36' W. 30.05 29.98 Funchal, Madeira . 30.11 30.15 30.10 30.03! 32° 23' N. 64° 40/ W. 30.14 30.061 Bermuda Islands . 29.97 | 29.93 30.13 30.07 5° 24' N. 0° 10' E. I 30.09 30.03 Christiansb'g, Guinea 30.00 29.91 29.96 30.00 | 4° 56' S. 55° 39' W. 29.92 29.94 Cayenne, Fr. Guiana 29.95 29.91 29.72 29.72 33° 56' S. 18° 27 E. 29.52 29.43 Cape Town, S. Africa 30.17 30.00 29.27 29.23 34° 37' S. 58° 21' W.

Buenos Ayres 30.15 30.01

The polar boundaries of the N. E. and S. E. trades are marked by a high pressure (at 30° to 35° N. and at 20° to 30° S.), while the space intervening between the two trades—the belt of equatorial calms and variable winds, has a comparatively low pressure. It should be remarked that this low pressure remains on the northern hemisphere, changing from 10° to 15° N. in our summer and from 0° to 5° in our winter. The air from north and south is attracted towards this belt of low pressure, and, as the conditions of the tropics are very uniform, the winds also are very regular.

A comparison of stations in the west and east of the ocean will show that pressure is generally higher in the east (as in Madeira compared with Bermuda, in Christiansburg compared with Cayenne, and Cape Town compared with Buenos Ayres). This is an additional cause for the easting of the trade-winds near the American continent.

Pressure is extremely low in the higher latitudes of the southern hemisphere.

Between 559 and 60° it is lower than around Iceland, the lowest known in the northern hemisphere. The great permanence and strength of the westerly winds in the southern temperate zone is explained by this. (See Plates 5, 6, and 14.)

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The islands to the N. W. of Europe have still the climate of the Atlantic Ocean. Only one of them, the largest and most northerly, Iceland, has some of the characteristics of the polar zone.

Near Iceland, on account of the heated current of the gulf-stream, is the lowest pressure of the northern hemisphere, and though it is especially marked in autumn and winter it is also conspicuous at the other seasons. As is to be expected from a country in such a position, the winds are very changeable, according to the shifting of the centre of lowest pressure to the north and south. The equatorial winds, S. W., and the polar, N. E., prevail in turn.

The Faröe islands have prevailing S. W. winds at all seasons. This is even more the case at the Shetland islands, and in Great Britain generally, as is shown by percentages in the next table.

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Zone 5. N. 15. Stykkisholm, N. W. Iceland

6. N. 19. Reikiavik, W. Iceland.
6. N. 21. Thorshavn, Faroe Islands
6. N. 22, 23. Shetland Islands
7. N. 27. W. Scotland, 58°-59° N.
7. N. 29, 31. W. Scotland, 56°-58° N.
7. N. 33. W. Scotland, 55°-56 N.
7. N. 39 and 43. E. Scotland, 560-58° N.
8. N. 39. Ireland, 530-54° N.
8. N. 44 and 48. Ireland, 51°–53° N.
8. N. 113. Greenwich, S. E. Eugland

4 17 27 11 13 11 9

2 25 25 15 12 13 6 161 12 9 21 16 14 7 51 13 29 19 10 2 22 3 2 11 11 7 10 8 26 18 8 10 12 7 13 12 23 14 10 11 11 6 10 12 20 19 12 12 8 4 12 13 25 16 10 10 9 11 6 9 26 18 11 7 7 8 7 13 30 18 10 5 8 11 7 11 23 23 12 6 11 8 12 7 24 22 9 6

9 9 9 23 23 12 5 10 10 10 6 24 22 11 8 9 11 9 13 22 16 12

6 5 8 10 28 23 12 8 11 7 9 8 13 24 18 5 6 10 13 17 24 18 8 5 4 7 10 20 20 25 8 11 6 11 13 22 13 16 10 13 5 6 9 36 13 7 11 11 6 6 12 32 127

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There is little difference between the winds in winter and summer, from Faröe islands to southern England. A very slight one only can be detected in the greater number of W. and N. W. winds in summer. This applies not only to Great Britain, but also to the greatest part of northern and central Europe. It is due to two causes: First, the belt of highest barometer is more northerly in summer than in winter; and second, part of the air is attracted towards the depression of Central Asia.

In Great Britain the influence of the last cause is very small, as Central Asia is too distant, and the depression about Iceland so near, that it must act very powerfully even in summer. But the further we advance eastward the greater is the influence of the depression in Central Asia, and consequently the greater the difference between the direction of the wind in winter and summer. The next table gives the mean direction of the wind in Great Britain and Iceland.

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S. 87° E. .45 S. 74° E. 1.23 S. 68° E. 1.33 S. 75° E. .35
N. 78 E. .21 N. 17 E. .06 N. 54 E. .26 N. SO E. 1.19
N. 14 E. 1.03 S. 66 W..21 N. 77 W..13 S. 51 W.1.16
S. 36 W.1.13 S. 70 W..22, S. 50 W..26 S. 55 W./.34
S. 58 W..28 S. 53 W..351 S. 51 W..36 S. 55 W..40
S. 67 W..18 S. 65 W..18.) S. 53 W..34 S. 62 W..40
N. 70 W..104 S. 8S W..31 S. 73 W..31 S. 61 W..36}
S. 54 W..13 S. 88 W..39 S. 70 W..19 S. 64 W..204
N. 2 W..08 N. 81 W..29 S. 84 W..19 S. 75 W..31
N. 57 W..02 S. 61 W..28 S. 69 W..14, S. 55 W..25
N. 45 W..08 N. 87 W..26} S. 73 W..101 s. 72 W..21

(See also maps, Plates 5, 6, and 9; and map of Isobars, Plate 14.)

The ratio of resultant is less in spring than at other seasons. This is caused by the great increase of pressure in the Polar region, as has been shown before. N. E. winds are oftener experienced in spring than at other seasons.

I must further remark that the character of the winds in Great Britain and the adjoining islands is strictly oceanic i. e., such as would be found in the same latitudes on the oceans. The relative position of the land and sea have scarcely any influence. This is due, first, to the great difference of pressure between north and south, and the great strength of the winds which is the result, so that local causes are comparatively unimportant; second, to the small extent of land, which, being besides pervaded by the influence of the sea, is neither much more heated in summer, nor much more cooled in winter than the surrounding ocean. (See Plates 9 and 12.)

The conditions of the Scandinavian Peninsula are very different. It is by itself a large body of land. Besides this, the high mountain chain rising near its western coast is a great barrier to the influence of the Atlantic Ocean on the interior. The result is a much more continental climate than could be expected from a country so near to the Atlantic Ocean.

In many respects the physical features resemble those of Alaska, where the contrast between the mild, equable climate of the coast and the excessive seasons of the interior is equally great. The winds of the Scandinavian Peninsula are shown in the two following tables; in the first by percentages, and in the second in direction.

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5 40

Zone 7. N. 56. Christiania, S. Norway.

6. N. 27. Christiansund, W. Norway
6. N. 26. Dovre, Inner Norway
5. N. 19. Bossekop, N. Norway
4. N. 18. Hammerfest, N. Norway
4. N. 19. Vardö, N. Norway
3.

Mossel Bay, Spitzbergen
3.

Ice Fjord, Spitzbergen
3.

Hecla Cove, Spitzbergen
4. N. 16. Bear Island (between Norway

and Spitzbergen)
5. N. 23, 24, 25. N. Sweden.
6. N. 35. E. Sweden
7. N. 90. S. E. Sweden
7. N. 89. S. W. Sweden
7. N. 68. Lund, s, Sweden

12 16 9 16 30 8 4 5 29 30 6 8 12 4 38 14 25 6 7 3 10 24 11 3 4 10 29 12 19 17 7 16 4 2

6 4 23

5 2 3 6 53 11 6 13 27 40 0 0 71 20 7 1 3 30 42 10 6 4 3 10 7 17 11 17 6 13 17 7 3 9 31 28 8 12 15 7 28 8 5 2 24

9 5 11 5 46 8 12

1 2 45 2 36 3 5

12 13 19 21 11 9 8 7 15 10 19 15 5 7 14 15

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19 13 10 9! 14 8 15 13
15 12 13 13 23 11 8 5

9 5 9 7 31 17 10 12
12 9 10 10 13 15 17 10
9 8 8 S 20 19 20 18
7 7 7 12 12 17 21 18

4 13 31 17 12 11 6 15 11 5 10 22 15 13 8 14 8 7 8 20 18 14 11 13 10 7 8 13 201 16 12 10 12 14 10 17 19 11 10 7 8 10 13 14 22 14 11

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Christiania, Southern Norway.
Sandösund, Southern Norway.
Christiansund, Western Norway
Dovre, Inner Norway
Hammerfest, Northern Norway
Vardö, Northern Norway
Bossekop, Northern Norway
Haparanda, Northern Sweden
Southwestern Sweden
Southeastern Sweden

N. 57° E. 1.24 S. 42° E. 1.28 N. 39° E. 1.32 N. 31° E. 1.41
N. 8 W.1.05 S. 49 W..29 S. 49 W..09 N. 39 W..08
S. 31 W..03 N. 20 W..23 S. 13 W..24 S. 3 W..32
S. 18 W..08 S. 48 W..08 S. 14 W..16 S. 15 W..19
S. 23 E. 1.19 S. 31 E, 1.02 S. 12 E. .24 S. 21 E. .42)
N. 75 W..19 N. 53 E. .14 S. 53 W..25 S. 50 W..38
S. 43 E. 1.47 N. 34 E. .25 S. 60 E. .24 S. 53 E. 1.61
S. 25 E. 1.12 S. 24 E. .111 S. 15 E. .06 S. 30 E. 1.09
S. 72 W.!.01 S. 57 W..25 S. 6 W..15 S. 14 W..09
N. 5 W.1.06 S. 71 W..145 s. 66 W..12} S. 83 W..103

In winter the whole coast of Norway has monsoon winds, blowing from the land to the sea, they are N. and N. E. at Christiania, S. E. at Christiansund, Bossekop and Hammerfest, and S. W. at Vardöe. In summer the conditions are reversed.

This was shown some years ago by the best authority in these matters, Prof. H. Mohn. He is of the opinion that the winds are deflected about 90° to the right of the direction they would have if they blew directly from the land in winter and from the sea in summer.

It must, however, be observed that in this result the number of observations alone is taken into account. The storms on the Atlantic coast of Norway are very violent, and the winds during their prevalence mostly S. and W. A south wind should prevail in Norway, taking into account the strength of winds and aside from local influences.

The high station of Dovre, in the interior, has largely prevailing S. winds. this we see the influence of the high pressure to the S. and in the interior of the continent and of low pressure on the ocean to the W. and N. (See Plates 9 and 14.)

In northern Norway the winds are variable in summer and decidedly from the S. in the winter. In the latter season the general distribution of pressure in the

In

? Oversigt of Norges Klimatologi. See also Norsk Meteorologisk Aarbog.

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