Snow is hardly ever seen on the banks of the Oregon or Columbia river, and ice on the river lasts only a very few days. The lowest temperature which Mr. Ball once observed there in the winter of 1833 was 6½° of Reaumur below the freezing point, or 17.4° Fahrenheit (Message from the President of the United States to Congress, 1844, p. 160; and Forry, Clim. of the U. States, p. 49, 67, and 73). A cursory glance at the summer and winter temperatures above given, shews that on and near the west coast, a true insular climate prevails. The winter cold is less than in the western parts of the old continent, and the summers are much cooler. The most striking contrast is presented by comparing the mouth of the Oregon with Forts Snelling and Howard, and the Council Bluffs, in the interior of the Mississipi and Missouri basin (Lat. 44°-46°),—where, to speak in the language of Buffon, we find an excessive, or true continental climate,—a winter cold, on single days, of -28°.4 and -30°.6 Reaumur (-32° and -37° Fahr.), followed by mean summer temperatures of 16°.8 and 17°.5 Reaumur (69° and 71°.4 Fahr.)

[19] p. 10.—“As if America had emerged later from the chaotic watery covering.”

An acute enquirer into nature, Benjamin Smith Barton, said long since with great truth, (Fragments of the Natural History of Pennsylvania, P. i. p. 4), “I cannot but deem it a puerile supposition, unsupported by the evidence of nature, that a great part of America has probably later emerged from the bosom of the ocean than the other continents.” The same subject was touched on by myself in a memoir on the primitive nations of America (Neue Berlinische Monatschrift, Bd. xv. 1806, S. 190). “Writers generally and justly praised have repeated but too often that America is in every sense of the word a New Continent. Her luxuriance of vegetation, the abundant waters of her enormous rivers, the unrepose of her powerful volcanoes, all (say they) proclaim that the still trembling earth, from the face of which the waters have not yet dried off, is here nearer to the chaotic primordial state than in the Old Continent. Such ideas appeared to me, long before I commenced my travels, alike unphilosophical and contrary to generally acknowledged physical laws. Fantastic images of terrestrial youth, and unrepose associated on the one hand,—and on the other, those of increasing dryness, and inertia in maturer age,—could only have presented themselves to minds more inclined to draw ingenious or striking contrasts between the two hemispheres, than to strive to comprehend, in one general view, the construction of the entire globe. Are we to regard the south of Italy as more modern than its northern portions, because the former is almost incessantly disquieted by earthquakes and volcanic eruptions? Besides, what small phenomena are the volcanoes and earthquakes of the present day, in comparison with those revolutions of nature which the geologist must suppose to have accompanied, in the chaotic state of the earth, the elevation, solidification, disruptions, and cleavings of the mountain masses? Diversity of causes must produce diversity in the operations of natural forces, in countries remote as well as near. Perhaps the volcanoes of the new continent, (of which I still reckon above 28 in a state of activity), have only continued to burn longer than others, because the lofty mountain ridges, on which they have broken forth in rows or series above long subterranean fissures, are nearer to the sea, and because this proximity seems, with a few exceptions, to affect the energy of the subterranean fires in some way not yet sufficiently explained. Besides, both earthquakes and fire-emitting mountains have periods of activity alternating with periods of repose. At the present moment,” (I wrote thus 42 years ago!) “physical disquiet and political calm reign in the New Continent, while in the Old the desolating strife of nations disturbs the enjoyment of the repose of nature. Perhaps a time is coming when, in this singular contrast between physical and moral forces, the two sides of the Atlantic will change parts. Volcanoes are quiescent for centuries before they burst forth anew; and the idea that in the so-called older countries, a certain peace must prevail in nature, is founded on a mere play of the imagination. There exists no reason for assuming one entire side of our planet to be older or newer than the other. Islands are indeed raised from the bed of the ocean by volcanic action, and gradually heightened by coral animals, as the Azores and many low flat islands of the Pacific; and these may indeed be said to be newer than many Plutonic formations of the European central chain. A small district of the earth, surrounded, like Bohemia and Kashmeer, (and like many of the vallies in the Moon), by annular mountains, may, by partial inundations, be long covered with water; and after the flowing off of this lake or inland sea, the ground on which vegetation begins gradually to establish itself might be said, figuratively, to be of recent origin. Islands have become connected with each other by the elevation of fresh masses of land; and parts of the previously dry land have been submerged by the subsidence of the oscillating ground; but submersions so general as to embrace a hemisphere, can, from hydrostatic laws, only be imagined as extending at the same time over all parts of the earth. The sea cannot permanently overflow the boundless plains of the Orinoco and the Amazons, without also overwhelming the plains adjoining the Baltic. The sequence and identity of the sedimentary strata, and of the organic remains of plants and animals belonging to the ancient world enclosed in those strata, shew that several great depositions have taken place almost simultaneously over the entire globe.” (For the fossil vegetable remains in the coal formation in North America and in Europe, compare Adolph Brongniart, Prodrome d’une Hist. des Végétaux Fossiles, p. 179; and Charles Lyell’s Travels in North America, vol. ii. p. 20).

[20] p. 10.—“The Southern Hemisphere is cooler and moister than our Northern half of the globe.”

Chili, Buenos Ayres, and the southern parts of Brazil and Peru, have all, as a result of the narrowness of the continent of South America as it tapers towards the south, a true “insular climate;” or a climate of cool summers and mild winters. As far as the 48th or 50th parallel of latitude this character of the Southern Hemisphere may be regarded as an advantage, but farther on towards the Antarctic Pole, South America gradually becomes an inhospitable wilderness. The difference of latitude of the southern terminating points of Australia, (including Van Diemen Island), of Africa, and of America,—gives to each of these continents a peculiar character. The Straits of Magellan are between the 53d and 54th degrees of latitude, and yet in December and January, when the sun is 18 hours above the horizon, the temperature sinks to 4° Reaumur, or 41° Fahrenheit. Snow falls almost daily, and the highest atmospheric temperature observed by Churruca (1788) in December, (the summer of those regions), was not above 9° R., or 52°.2 Fahr. The Cabo Pilar, whose towering rock, though only 218 toises, or 1394 English feet high, may be regarded as the southern termination of the chain of the Andes, is almost in the same latitude as Berlin. (Relacion del Viage al Estrecho de Magallanes, apendice, 1793, p. 76.)

While in the Northern Hemisphere all the continents attain a sort of mean limit towards the Pole, coinciding pretty regularly with the parallel of 70° the terminating points in the Southern Hemisphere,—of America, in the deeply indented and intersected Tierra del Fuego,—of Australia,—and of Africa,—are respectively 34°, 46½°, and 56° distant from the south pole. The temperature of the very unequal extents of ocean, which divide these southern points from the icy pole, contributes very materially to modify their climates. The areas of dry land in the Northern and Southern Hemispheres are to each other in the proportion of 3 to 1. But this inferiority in extent of continental masses in the Southern Hemisphere, as compared with the Northern, belongs much more to the temperate than to the torrid zone. In the temperate zones of the Northern and Southern Hemispheres, the ratio is as 13 to 1; in the torrid zones as 5 to 4. The great inequality in the distribution of the dry land exercises a very sensible influence on the strength of the ascending aerial current which turns towards the southern pole, and on the temperature of the Southern Hemisphere. Some of the noblest forms of tropical vegetation, for example the tree-ferns, advance south of the equator as far as the parallels of 46°, and of even 53°; whereas north of the equator they are not found beyond the tropic of Cancer. (Robert Brown, Appendix to Flinders’ Voyage, p. 575 and 584; Humboldt, de distributione geographica Plantarum, p. 81–85.) Tree-ferns thrive extremely well at Hobart Town in Van Diemen Island, (lat. 42° 53′), where the mean annual temperature is 9° Reaumur, or 52°.2 Fahrenheit, and is therefore 1°.6 Reaumur, or 3°.6 Fahrenheit, less than that of Toulon. Rome is almost a degree of latitude farther from the equator than Hobart Town, and has an annual temperature of 12°.3 R., or 59°.8 Fahr.;—a winter temperature of 6°.5 R., or 46°.4 Fahr.,—and a summer temperature of 24° R., or 86° Fahr.; these three values being in Hobart Town 8°.9, 4°.5, and 13°.8 R., or 52°.0, 42°.2, and 63°.0 Fahr. In Dusky Bay, New Zealand, tree-ferns grow in S. lat. 46° 8′, and in the Auckland and Campbell Islands, even in 53° S. lat. (Jos. Hooker, Flora Antarctica, 1844, p. 107.)

In the Archipelago of Tierra del Fuego,—where, in the same latitude as Dublin, the mean winter temperature is 0°.4 Reaumur, (33° Fah.) and the mean summer temperature only 8° R., or 50° Fahr.,—Captain King found the “vegetation thriving most luxuriantly in large woody-stemmed trees of Fuchsia and Veronica”; while this vigour of vegetation, which, especially on the western coast of America in 38° and 40° of south latitude, is so picturesquely described by Charles Darwin, suddenly disappears south of Cape Horn, on the rocks of the Southern Orkney and Shetland Islands, and of the Sandwich Archipelago. These Islands, but scantily covered with grass, moss, and lichens, “Terres de Désolation,” as the French navigators call them, are still far north of the Antarctic Circle; whereas in the Northern Hemisphere in 70° of latitude, at the extremity of Scandinavia, fir-trees attain a height of between 60 and 70 English feet. (Compare Darwin in the “Journal of Researches,” 1845, p. 244, with King in vol. i. of the Narrative of the Voyages of the Adventure and Beagle, p. 577.) If we compare Tierra del Fuego, and particularly Port Famine in the Straits of Magellan in lat. 53° 38′, with Berlin, which is one degree nearer the equator, we find for

Berlin6°.8, -0°.5R., 47°.2, 30°.8Fahr.; and for
13°.9 63°.2
Port Famine4°.7, 1°.2R., 42°.6, 34°.8Fahr.
8°.0 50°.0

I subjoin in one view the few well-assured temperature data which we at present possess, for the lands of the temperate zone in the Southern Hemisphere, and which may be compared with the temperatures of the Northern Hemisphere, in most parts of which the distribution into summer heat and winter cold is so different and so much less equable. I employ the convenient method of notation before used and explained in pages [129]–[131].

Place. South Latitude. Mean Annual, Winter, and Summer Temperature.
Reaumur. Fahrenheit.
Sidney and Paramatta (New Holland.)33°.50′ 14°.5 10°.0 64°.5 54°.5
————
20°.2 77°.5
Cape Town (Africa.) 33°.55′ 15°.011°.8 65°.7 58°.5
————
18°.3 73°.3
Buenos Ayres 34°.17′ 13°.59°.1 62°.4 52°.5
————
18°.2 73°.0
Monte Video 34°.54′ 15°.511°.3 66°.8 57°.3
——?——
20°.2 77°.5
Hobart Town (Van Diemen Island.)42°.45′ 9°.1 4°.5 52°.5 42°.2
————
13°.8 63°.0
Port Famine (Straits of Magellan.)53°.38′ 4°.7 1°.2 42°.6 34°.8
————
8°.0 50°.0