Cosmos: A Sketch of the Physical Description of the Universe, Vol. 1

by Alexander von Humboldt

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Places. Lat- Ele- Mean Win- Spring. Sum- Aut- Number of the
it- va- of the ter. mer. umn. years of the
tude tion. Year. observation

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deg ' Eng.ft. Fahr.

Bordeaux 44 50 25.6 57.0 43.0 56.0 71.0 58.0 10
Stras- 48 35 479.0 49.6 34.5 50.0 64.6 50.0 35
bourg
Heid- 49 24 333.5 59.5 34.0 50.0 64.3 49.7 20
elberg
Manheim 49 29 300.5 50.6 34.6 50.8 67.1 49.5 12
Wurzburg 49 48 562.5 50.2 35.5 50.5 65.7 49.4 27
Frank-
fort on
Maine 50 7 388.5 49.5 33.3 50.0 64.4 49.4 19
Berlin 52 31 102.3 47.5 31.0 46.6 63.6 47.5 23
Cher-
bourg (no
wine) 49 39 …. 52.1 41.5 50.8 61.7 54.2 3
Dublin
(ditto) 53 23 …. 49.1 40.2 47.1 59.6 49.7 13
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The great accordance in the distribution of the annual temperature through the different seasons, as presented by the results obtained for the valleys of the Rhine and Maine, tends to confirm the accuracy of these meteorological observations. The months of December, January, and February are reckoned as winter months. When the different qualities of the wines produced in Franconia, and in the countries around the Baltic, are compared with the mean summer and autumn temperature of Wurzburg and Berlin, we are almost surprised to find a difference of only about two degrees. The difference in the spring is about four degrees. The influence of late May frosts on the flowering season, and after a correspondingly cold winter, is almost as important an element as the time of the subsequent ripening of the grape. The difference alluded to in the text between the true temperature of the surface of the ground and the indications of a thermometer suspended in the shade and protected from extraneous influences, is inferred by Dove from a consideration of the results of fifteen years' observations made at the Chiswick Gardens. See Dove, in 'Bericht uber die Verhandl. der Berl. Akad. der Wiss.', August, 1844, s. 285.

At Bordeaux, in the valley of the Garonne (44 degrees 50' lat.), the mean annual winter, summer, and autumn temperatures are respectively 57 degrees, 43 degrees, 71 degrees, and 58 degrees. In the plains near the p 325 Baltic (52 degrees 30' lat.), where a wine is produced that can scarcely be considered potable, these numbers are as follows: 47.5 degrees, 30 degrees, 63.7 degrees, and 47.5 degrees. If it should appear strange that the great differences indicated by the influence of climate on the production of wine should not be more clearly manifested by our thermometers, the circumstance will appear less singular when we remember that a thermometer standing in the shade, and protected from the effect of direct insolation and nocturnal radiation can not, at all seasong of the year, and during all periodic changes of heat, indicate the true superficial temperature of the ground exposed to the whole effect of the sun's rays.

The same relations which exist between the equable littoral climate of the peninsula of Brittany, and the lower winter and p 326 higher summer temperature of the remainder of the continent of France, are likewise manifested in some degree, between Europe and the great continent of Asia, of which the former may be considered to constitute the western peninsula. Europe owes its milder climate, in the first place, to its position with respect to Africa, whose wide extent of tropical land is favorable to the ascending current, while the equatorial region to the south of Asia is almost wholly oceanic; and next to its deeply-articulated configuration, to the vicinity of the ocean on its western shores; and, lastly, to the existence of an open sea, which bounds its northern confines. Europe would therefore become colder* if Africa were to be overflowed by the ocean; of if the mythical Atlantis were to arise and connect Europe with North America; or if the Gulf Stream were no longer to diffuse the warming influence of its waters into the North Sea; or if, finally, another mass of solid land should be upheaved by volcanic action, and interposed between the Scandinavian peninsula and Spitzbergen.

[footnote] *See my memoir, 'Ueber die Haupt-Ursachen der Temperaturverschiedenheit auf der Erdoberfläche', in the 'Abhandl. der Akad. der Wissensch. zu Berlin von dem Jahr' 1827, s. 311.

If we observe that in Europe the mean annual temperature falls as we proceed, from west to east, under the same parallel of latitude, from the Atlantic shores of France through Germany, Poland, and Russia, toward the Uralian Mountains, the main cause of this phenomenon of increasing cold must be sought in the form of the continent (which becomes less indented, and wider, and more compact as we advance), in the increasing distance from seas, and in the diminished influence of westerly winds. Beyond the Uralian Mountains these winds are converted into cool land-winds, blowing over extended tracts covered with ice and show. The cold of western Siberia is to be ascribed to these relations of configuration and atmospheric currents, and not — as Hippocrates and Trogus Pompeius, and even celebrated travelers of the eighteenth century conjectures — to the great elevation of the soil above the level of the sea.*

[footnote] *The general level of Siberia, from Tobolsk, Tomsk, and Barnaul, from the Altai Mountains to the Polar Sea, is not so high as that of Mauheim and Dresden; indeed, Irkutsk, far to the east of the Jenisei, is only 1330 feet above the level of the sea, or about one third lower than Munich.

If we pass from the differences of temperature manifested in the plains to the inequalities of the polyhedric form of the surface of our planet, we shall have to consider mountains either in relation to their influence on the climate of neighboring p 327 valleys, or according to the effects of the hyposometrical relations on their own summits, which often spread into elevated plateaux. The division of mountains into chains separates the earth's surface into different basins, which are often narrow and walled in, forming caldron-like valleys, and (as in Greece and in part of Asia Minor) constitute an individual local climate with respect to heat, moisture, transparancy of atmosphere, and frequency of winds and storms. These circumstances have at all times exercised a powerful influence on the character and cultivation of natural products, and on the manners and institutions of neighboring nations, and even on the feelings with which they regard one another. This character of 'geographical individuality' attains its maximum, if we may be allowed so to speak, in countries where the differences in the configuration of the soil are the greatest possible, either in a vertical or horizontal direction, both in relief and in the articulation of the continent. The greatest contrast to these varieties in the relations of the surface of the earth are manifested in the Steppes of Northern Asia, the grassy plains (savannahs, llanos, and pampas) of the New Continent, the heath ('Ericeta') of Europe, and the sandy and stony deserts of Africa.