84 



AMERICA. 



there, as in many parts of all the divisions of the east- 

 tern continent, contended with the flood, the forest, or 

 thedesert; buteachof them hud been allowed to assume 

 its dominion to the full extent of its powers. As little 

 had cultivation clothed the fields with artificial plants, 

 or stocked them with trained animals, the native local- 

 ities of which, and their habits in a state of nature, 

 had been forgotten and lost, during successive ages of 

 cultivation and change. It is true that the few nations 

 on the American continent among whom traces of 

 civilisation were found were migrant races, for it ap- 

 pears that in no case can there be improvement with- 

 out migration ; but, unlike the migrants of the old 

 continent, they appear to have migrated without car- 

 rying along with them the means of their subsistence, 

 and to have trusted to the day for the day's supply, in 

 the same manner as is done by the savage. They 

 drove no flocks or herds, they carried no seed corn. 

 When they settled, indeed, they did make a little 

 provision against the season of want, but that pro- 

 vision was all obtained from the natural produce of 

 the country in which they resided ; so that, when 

 the Mexican empire was in the zenith of its power, it 

 could not be said that it had added even one new 

 plant to the soil, or one new animal to the pasture. 



Up to the time of its colonisation by Europeans, 

 America may, therefore, be regarded as a country 

 moulded wholly by the operation of natural causes ; 

 and throughout the greater part of its vast range in 

 latitude it must, from the extent of sea which lies 

 between it and the other continents, have been 

 moulded by causes operating within itself. The na- 

 tural history of America is, therefore, in a great mea- 

 sure, a subject complete in itself, between which and 

 the several parts of the eastern continent there are 

 not the same relations as these parts have to each 

 other. No doubt it is subject to the same grand laws 

 of the year, on which climate and seasons depend ; 

 and the plants and the animals must be in accordance 

 with these. But there are peculiarities in the form, 

 the position, and the surface of America, which mo- 

 dify its climate, and through that, all its growing and 

 living productions ; and we must take at least some 

 knowledge of these particulars along with us in order 

 rationally to understand even the elements of its 

 natural history. 



The position of America upon the map is in itself 

 worthy of attention. There is no country which lies 

 so far upon a meridian, or has its central elevation so 

 much in the meridional direction. What with land, 

 M'hat with ice, it may be said to reach the pole at the 

 north, and thence it extends unbroken to the latitude 

 of about 56 south ; so that in round numbers it may 

 be said to oppose to the currents of the sea and the 

 atmosphere a barrier of ten thousand miles in length, 

 or, taking the flexure of the mountains which bend 

 much westward in the northern part of the country, 

 of not much less than twelve thousand. That barrier, 

 too, is not only complete against the sea, but against 

 all those lower strata of the atmosphere which can be 

 supposed to have much effect upon plants or animals; 

 for, with few interruptions of any kind, and hardly 

 any save whore the isthmus is narrowest, is there 

 any interruption that can be supposed to admit 

 of an interchange of climate ; for though there are 

 some passes in the isthmus, these are overlapped by 

 the projecting high land in Venezuela, so that any 

 wind from the east, blowing so far to the northward 

 as to clear Cape Gallina?, would be taken by the 



table land of Mexico, and turned by the eastern side 

 of the StonyMountains down the great central valley 

 of North America. To the northward of the Gulf 

 of Mexico, the mountains near the shore of the At- 

 lantic confine the influence of that ocean to the line 

 of the coast, to which the valley of the St. Lawrence 

 barely forms an exception, as the influence of the 

 great lakes at the upper end counteracts that of the 

 sea at the lower, and the entrance of the latter be- 

 tween the high grounds below Quebec is a mere pass, 

 and that pass interrupted by Newfoundland and 

 the other islands. South of the Gulf of Mexico, the 

 wind from the tropical Atlantic sweeps along the 

 valleys of the Orinoco and the! Amazon ; but these are 

 both, at their terminations, cut off" by the lofty cor- 

 dillcras of the Andes. South of the Amazon the dif- 

 ferent mountain ridges in the eastern part of Brazil 

 again interrupt the communication between the inte- 

 rior of the country and the sea ; and even in the flat 

 country to the southward of La Plata, though the 

 current of sea air sweeps a considerable way over the 

 Pampas, the Chilian Andes form so effectual a bar- 

 rier to it that it never reaches the western shore. 



Thus, the slope from the great summit eastward, 

 which comprises by ninch the greater part of the 

 whole surface of the continent, is divided into a 

 number of valleys or basins, having their atmospheric 

 motions in the direction of their own lengths ; some- 

 times between the mountains and the sea in nearly a 

 direct line, as in the case of the valley of the Amazon; 

 sometimes oblique, as in the St. Lawrence ; and some- 

 times directly across, as in the central valley of the 

 Mississippi. 



On the western side, the mountains are, generally 

 speaking, so near the sea as only to leave a mere 

 margin, or at best but a narrow plain, unless in some 

 places towards the north, where the connexion be- 

 tween the sides of the continent is interrupted by 

 the cross current of the central valley. 



In general, the current, both of the ocean and the 

 atmosphere (in so far as the latter of these depends 

 on the former), sets across the Atlantic from the cast, 

 sometimes a little south of the equator, and some- 

 times a little north ; but upon the average of the 

 year only a degree or two north of the equator itself. 

 The greater portion of both currents is turned by the 

 northern heights on the left bank of the Amazon, and 

 circulates round the Gulf of Mexico, the aerial part 

 of it ascending the valley of the Mississippi, when 

 the regions to the north have been dried by the 

 action of the summer ; and the aquatic part circulating 

 round the Atlantic, in the gulf stream and its con- 

 tinuations. In summer, when the current is at its 

 greatest distance northward, and also at its greatest 

 strength, because of the less interrupted run which it 

 has at that season, the weather up to very high lati- 

 tudes in the central part is warm, so as to lipen in 

 Canada, fruits which can hardly be brought to ma- 

 turity in the milder climates of Europe ; and were it 

 not for the evaporation produced by the vast surface 

 of lakes in that part of America, and also by the 

 forests with which many parts of the country are 

 shaded, there is no doubt that the surface there would 

 soon assume a more sterile and dreary character 

 than is to be met with even in the bleaker parts of 

 Siberia." 



The countries which open to the sea further south- 

 ward receive an abundance of humidity, though they 

 receive it seasonably only ; and in them, though 



