II".-, 



METEOROLOGY. 



[THE CLIMATE OP AMERICA. 



at Perth, in Wentern Australia, the range is from 55 of 

 winter, to 76" of summer intuit ; and in the same latitude, 

 north, in Egypt, at the delta of the Mile, the range 

 u from 60 to 60 in winter, and from 80 to 90 in 

 summer. 



A great variety of circumstances combine to produce 

 the low mean temperature of the northern portion of the 

 American continent, a brief investigation of which may 

 prove instructive. 80 far as is at present ascertained, 

 one almost unbroken tract of frozen land or water extends 

 between 60 N. lat. and the North Pole, a considerable 

 portion being at a great elevation above the sea-level. 

 The atmosphere over the whole of this region is, of 

 course, cold, and free from aqueous vapour, and rarely, if 

 ever, intermixes with warm currents of air from the 

 south, to an extent sufficient to permanently modify its 

 average temperature. Hence, whenever a N., N. W., or 

 N.E. wind sets in, the greater portion of North America 

 U exposed to a most inclement and chilling blast ; and the 

 immense quantities of icebergs floating southward from 

 the Frozen Ocean, at certain seasons of the year, conduce 

 most powerfully to increase this condition. The north- 

 western portion of the continent is hedged in by a long 

 range of hills the " Rocky Mountains" which extend 

 from 70 D to about 35 north latitude, with scarcely a 

 break, and are continued to the extremity of the southern 

 portion of the continent at Cape Horn, in latitude 55 S. 

 The greater part of North America, comprised within the 

 parallels of 35 and 70 N., is, therefore, completely shut 

 out from the influence of the warm Pacific Ocean, the 

 hill ranges being too high to permit of the passage of 

 warm aerial currents over their generally frozen summits. 

 On the east, the Gulf-stream, instead of impinging on its 

 shores, passes over the Atlantic in a north-easterly 

 direction, to Europe ; and on the south, the high table- 

 land of Mexico partly prevents the access of the hot 

 tropical currents. About California, however, on the 

 west coast, and beyond the Rocky Mountains, a more 

 equable and mild climate subsists, because there tho 

 interfering causes, above described, are absent, and 

 the genial air and moisture, arriving from the Pacific, 

 exert their full influence in tempering the climate of that 

 country. 



Not only is the climate of North America of a very 

 excessive type, but the range of temperature undergoes 

 most remarkably sudden variations. In some parts of 

 Canada, for instance, the thermometer will fall as much 

 as 60 in 36 hours ; and a variation of 30 J or 40, in the 

 course of 24 hours, is by no means an uncommon 

 occurrence during tho winter season. The effect of such 

 sudden changes which, in a moist climate, would be 

 positively injurious to animal life is, to a great extent, 

 moderated by the extreme dryness which prevails ; the 

 intense cold, of course, freeing the atmosphere from 

 every vestige of suspended aqueous vapour. To such an 

 extent does this occur, that, in the Arctic regions, the 

 breath, as driven from the lungs, has its moisture instantly 

 converted into minute particles of snow. The me- 

 chanical power of this extreme frost is often sufficient to 

 rend trees and rocks, by the expansion of the ice, as if 

 they had been blasted with gunpowder ; metals, if 

 touched by tho hand, <tc., blister the skin equally as 

 when rod-hot ; and even hydrophobia is common amongst 

 dogs, at Quebec, in December and January, just as 

 would be, with more likelihood, expected during the hot 

 months of summer. 



The southern part of Mexico, between 15 and 20 

 north latitude, owing to the varying elevation of the 

 land, presents some singular peculiarities of cl:.nate. 

 On tho tow-lyina coast tho heat is very great, the mean 

 annual temperature reaching an average of 70. On the 

 elevated table-land the mean is reduced to 64. The 

 climate* range hot, beneath a height of 900 feet from the 

 tea-level ; ttro/xrafc, at an elevation of from 4,000 to 

 > feet ; and become positively cold, at above 7,000 



i * . 



In a similar manner, and arising from like cause*, the 



Innate of Central America, extending between Mexico 



and the Isthmus of Panama, or between latitude* 18 



and 8 N., varies considerably. On both sides tho 

 shores are washed by the ocean ; the western by tho 

 Pacific, and tho eastern by the Caribbean sea ; and thu 

 temperature of the winter of each reaches nearly a i> 

 of 80- The temperature of tho low-lying dit 

 varies between 60 and 80 ; but a range of mountains of 

 considerable height (12,000 to 15,000 feet), bein 

 intermediate link joining the Andes of South Am 

 and the Rocky chain of the northern portion of tho 

 continent, must tend to modify considerably the heat, 

 which would otherwise be very great. The rains that 

 fall from May to October temper the climate on tlio 

 Pacific coast ; whilst those on the east side, falling 

 between October and May, have there a similar effect, 

 and render the country as healthy as any in the > 

 latitude; fostering, at the same time, the greatest 

 luxuriance and profusion amongst the vegetable pro- 

 ductions of tho country. 



In South America every extreme of climate is found, 

 this portion of the continent comprising all possible 

 variety of elevation, &c. In the north, near the equator, 

 and on tho east coast, the level is low, the air moist and 

 of a high temperature, and the rainfall, consequently, in 

 some seasons, enormous, always exceeding in Guiana 

 100 inches annually, and occasionally reaching to more 

 than double that quantity at places between 8 N. and 2 

 S. of the equator. Oil the west coast, the Andes, at an 

 average distance of about 103 miles inland, rob the air 

 of its moisture, as brought by the N. E. and S. E. trade- 

 winds ; and northwards, between the hills and the shore, 

 from lat. 30 S. to 10 S., the chief parts of Peru and 

 Chili present an almost rainless tract. To the south of 

 30 the air becomes more humid, the land being much 

 narrower than in the northern part ; and the prevalent 

 winds are from the west, bringing with them moisture from 

 the Pacific. The country, in tact, gradually assumes a 

 condition, southward, resembling that of an island, so 

 far as climate is concerned, extending thus as far as the 

 south of Patagonia, in latitude 55 S. The Andes shut 

 off the westerly breeze between 30 S. and 55 S., just as, 

 above the parallel of 30 S. to 10 S., they exclude the 

 easterly winds from the western coast ; and thus another 

 rainless tract is formed in the interior, occupying most 

 of the southern portion of South America. Tho cast 

 and south-east coasts of that continent have the constant 

 trade-winds from either the N.E. or S.E. ; and the level 

 plains of the interior, from 30 S. to the equator, are 

 thus generally well watered : large rivers, including the 

 mighty Amazon, flow through them, and a hot-moist 

 climate tends to produce an unequalled profusion of 

 most forms of animal and vegetable life. In theso 

 regions nature revels in her wildest and richest luxu- 

 riance ; and on no other part of the globe are tho 

 mineral, vegetable, and animal kingdoms so fully de- 

 veloped : yet this tract is, at present, almost entirely 

 unexplored, and its treasures jealously locked up by a 

 narrow and selfish policy, that can only be paralleled iu 

 the darkest pages of the history of civilisation. It 

 requires but little prophetic inspiration to foretel, that 

 when the resources of the country become expanded, 

 Brazil must hold a place in the world's histoiy, which its 

 extraordinary natural advantages will possibly make the 

 most brilliant of any epoch. It may, perhaps, be IMW 

 kept in reserve, to take, at some future time, the stul ',-,- 

 of present flourishing kingdoms, when their power and 

 riches have dwindled away, owing to the exhaustion of 

 those natural capabilities they at this time possess a 

 result which is suggested by the present condition of 

 many parts of Asia Minor and India. 



\\o have thus passed in review the leading particulars 

 which have reference to tho rainfall, mean and excessive 

 temperatures, &c., of the chief divisions of the earth; 

 and it now only remains to notice a few facts in connection 

 with the ocean-tracts, lakes, <tc., which cover the rest of 

 its surface. It has been explained, in previous pages, how 

 much tho climate of any place depends on a proximity 

 to, or distance from, tho sea. In the equatorial regions, 

 the Pacific, Indian, and Atlantic oceans are the cause of 

 the moist climates of tropical countries ; whilst, on the 



