NATURAL HISTOEY OF COMMERCE. 



177 



NATURAL HISTUKV oF COMMERCE, 



. HAITI.!: xi. 



THE NBW WORLD: KOBTH, CENTRAL, AHD SOUTH AMERICA. 



Climate and Soil Temperature* of Old and New World compared 

 Baw Produce, Animal, Vegetable, and Mineral. 



it,- and >'..//. A MII \. \- of any good map suffices 



\vthal tin- \-w World iiiu.it. ul' ncM-r.,.-itv, tliH'iT 



.ally in climate and soil from tin: <H<1 U'urld in 



|Mjnilin.t: latin* chief mountain ridge runs 



nortli iind south, or nrarly tit right angles to tin- mountain 



i -iiL-i- of the Old World. Tho counter-slope of this ridge 



^ting in South America of a IOIIL- 

 riding precipitously towards the I 

 Orran. Tho groat expanse, therefore, of the continent 

 ward, towards the Atlantic. This difference of 

 n the two continents is very remarkable. 

 Although tin; New World runs through every zone, 

 -! average temperature, compared with that of the 

 Old World, is lower. Tho Pacific, or western coast, is 

 warnu-r generally than the Atlantic or eastern coast, 

 ponding, in this respect, with the western and 

 n boundaries, respectively, of the Old World, 

 variations and resemblances are approximately 

 marked by the floral zones, as summarised in the 

 following chart : 



If we connect the corresponding points of the two 

 hemispheres by lines across the Atlantic and Pacific- 

 Oceans, we complete the botanical belts encircling the 

 world. We also see that the Arctic vegetation has no 

 analogue in the southern hemisphere, the land not ex- 

 tending, except in Patagonia, even to the limit of wheat, 

 and therefore far from the limit of hardier grains and of 

 trees. 



North America. We may infer from the contour and 

 vertical relief of North America many of its climatic 

 features. (1.) The land is broadest in the north, where 

 it expands to embrace the pole, and at the same time 

 lies so low as to interpose no barrier to the Arctic 

 blasts which sweep down from the north. (2.) The 

 tropical lands taper to an isthmus ; there is, therefore, 

 but a small part of the continent in the torrid zone, 

 and even this is mountainous. (3.) The west coast 

 consists of mountains and table-lands, which prevent 

 the warm and humid winds of the Pacific from crossing 

 the country; while the minor Appalachian ridge, on 

 the eastern side, completes a broad valley for the 

 Mississippi the uninterrupted channel for the northern 

 winds from the pole to the Gulf of Mexico. We see, 

 in consequence, that the central lowlands must be the 

 coldest part of North America a fact marked upon 

 the map by the deflection of the isothermal lines. 



One further element of climate must be taken into 

 account that of the marine currents. The Pacific 

 currents, not so well investigated as those of the 



These limits are not accurately defined. 

 116 N.E. 



Atlantic, contribute from their direction to raise the 

 tompei ho western coast. Tho Atlantic current* 



have already been considered in relation to the climate 

 ope. Let us now trace their 



of America. The source of the Gulf Stream 

 is in t lie Gulf of Mexico, where the boated waters, instead 

 of giving life and health, as they do to our own country, 

 increase the pestilential nature of the swamps of the 

 Mississippi delta and the Florida shores. At Cap* 

 Hattoras the Gulf Stream curves away from America in 

 a north-eat direction across tho Atlantic. The amelio- 

 rating powers of tho current are thus carried away from 

 tho continent where it originated, and instead thereof. 

 Arctic counter-currents sweep along the east shores) of 

 Greenland and down Baffin's Bay. These cold current* f 

 united, stream along tin- American shores, rendering the" 

 neighbouring lands hopelessly barren, almost to the 45tu 

 degree of latitude. Such is tho force of the Arctic 

 counter-current that it brings the icebergs, formed from 

 tho Greenland glaciers, southwards to the Gulf Stream, 

 where the denser and colder waters sink below the warm 

 flood, still driving the icebergs onward in opposition to 

 the surface flow, till the higher temperature dismantles 

 their pinnacles and dissolves their masses. Thus are 

 created the almost perpetual fogs of Newfoundland. The 

 limit of icebergs in the Atlantic is about 46, the latitude 

 reached in Europe by tho vine. Inland, two or three 

 degrees higher latitude, equivalent to that of Brittany 

 and Normandy, the ground is covered with snow for 

 more than half tho year; and beyond 50, a latitude 

 which London exceeds by nearly two degrees, there is 

 scarcely any cultivation. The vast forests of tho American 

 plains tend also to lower the temperature by intercepting 

 the sun's ravs, and thus preventing the absorption of 

 its heat. The enormous clearings, on the other hand* 

 have already sensibly modified tho rigour of the climate. 

 Nevertheless, the summers of North America are hot. 

 Its climate is essentially extreme, both from the ex- 

 tensive range of territory, and also from its being shut 

 out by the mountains from the equalising ocean winds. 

 Only the table-lands and mountains of the west are ex- 

 ceptional. The Mexican table-land enjoys continual 

 spring, the causes of which are easily seen. The isthmus 

 connecting the north and south continents exhibits every 

 phase of climate in vertical zones, from the almost un- 

 endurable tropical heat at the base, to Arctic elevations 

 and the line of perpetual frost. 



South America. The bulk of South America is tropical, 

 and its southern part diminishes in breadth rapidly on 

 approaching the pole. The climate of South America 

 is, therefore, latitude for latitude, of a higher tempera- 

 ture than that of North America. The table-land of 

 Quito (9,000 feet), like that of Mexico, is ever vernal, and 

 the Andes of the equator range through all the vertical 

 zones of vegetation. The region of Patagonia, riverless 

 and hilly, is dry, barren, and cold. 

 Soil. 



The New World is pre-eminently the country of great 

 plains, through which flow the longest rivers in the 

 world. These plains, except where physical conditions 

 evidently forbid, such as in the Arctic lowlands, are 

 generally fertile, the river valleys being exceedingly so, 

 and in particular, the basins of the Mississippi and the 

 Amazon. Parts of the plains, both north and south, 

 are barren, and sometimes salt, but there are no dttert* 

 to compare with those of Africa or Asia. Quite a fourth 

 of the soil is reckoned as unproductive. 



The great central plain or North America is divided 

 by a watershed 1,000 to 1,500 feet high, in lat. 49, into 

 the Mackenzie and the Mississippi lowlands. The Mac- 

 kenzie lowlands, towards the Arctic Ocean, form a 

 very gentle declivity, consisting of swampy and frozen 

 marshes. The Mississippi lowlands comprise the prairies 



