METEOROLOGY. 201 
wind. In Europe the direction is more southerly during winter than in the 
other seasons ; in spring (March and April) east winds occur, in summer 
(particularly in July) west and also north winds, and in autumn (especially 
in October) south winds. The strength of the wind depends partly on the 
season, being greatest in winter (January and February), and partly on the 
time of day, increasing in the morning towards noon, and then decreasing 
towards evening. 
In Europe the wind when changing appears to move for any one place 
from north by east, south and west, as seems to have been first suggested 
by Lord Bacon, and after him by Mariotte, Sturm, Lampadius, Schiibler, 
and others. The same relation seems to exist in North America. Dove 
first attempted to investigate this succession, and attained to the following 
results: In that part of the northern hemisphere where equatorial and 
polar currents alternate, the wind, as a general rule, shifts from the south 
by west, north, and east, and returns between south and west, as also 
between north and east, more frequently than in other directions. In the 
southern hemisphere the wind changes from south by east, north, and west, 
coming back more frequently between north and west, south and east. In 
the temperate, and probably in the frigid zones, where equatorial and polar 
currents constantly alternate, the wind at a mean appears to go round the 
quarters of the horizon in a definite direction, this direction being opposite 
in the two hemispheres. In the torrid zone, where polar currents alone 
prevail at the surface of the earth, there is no complete rotation of the wind. 
Nevertheless, whenever in the torrid zone, owing to the particular 
distribution of land and sea, a northern current alternates once a year with 
a southern, there will be but one complete rotation in the course of -the 
year, and that in the direction which predominates in the south temperate 
zone. 
The direction of the wind, as already remarked, exerts a decided influence 
on the height of the barometer. This, in western and central Europe, is 
highest during northern and eastern, lowest during southern and western 
winds. The following table contains the height of the barometer 
corresponding to the various winds, from observations made in the places 
mentioned : 
1 
| London. Paris. Berlin. Carlsruh. | Dantzig. |St. Petersburg.| Moscow. 
‘Millimetres. | Millimetres.| Millimeires.| Paris lines.| Paris lines.} Eng. inches. | Millimetres. 
We. 759.2 | 759.) | 758e) ae Te 888.7 28.06 743.1 
N.E. . | 760.7 | '759.5.| 759.4 | 335.0 | 338.6 28.15 745.1 
Fi) 34 °758.9» |) 757.2; |, 758.8. 983455 338.8 28.15 743.9 
S.E. . | 756.8 | 754.0 | 754.7 | 338.5 | 338.8 28.16 741.7 
See (a44 | Foo.) |) Tol.& eee |) oo 7 7 28.07 740.6 
W. P|) 7678 || °755.6 | 7560 | 398.7") 337.1 28.05 741.1 
N.W.. | 758.0 | 757.8 | 337.9 | 28.00 | 741.5 
SW. 2 1750.2 | 753.5 | (926 sean sa0.d | 28.07 "| 740s 
| 756.6 | 334.3 | 
Curves have been constructed for different places, showing the dependence 
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