In illustration of the contrast between the e. and w. coasts of A., we are told by the traveler already cited, that, at the mouth of the Columbia river,• the first half of Dec. presented one deluge of rain after another from the s.e., this weather winding up on the 16th of the month with a storm of thunder and lightning; "while, to mark the differ ence of climate between the two sides of the continent, the good folks of Montreal, though occupying a lower parallel than ourselves, were sleighing it merrily through the clearest and driest of atmospheres." Nor is the difference, according to the same authority, less palpable in the old continent than in the new. "To place in the most striking light the contrast in point of climate between the opposite shores of the old con tinent, Kamtchatka and the British isles may be said, with sufficient accuracy for this purpose, to lie in the same latitudes, and to present the same area, and even to occupy the same position with respect to the proximity of water; and yet, while the British isles, with but little foreign aid, feed at least 25,000,000 inhabitants, Kamtchatka, with the help of extraneous supplies, can barely prevent its population of 4000 souls from starving," But whatever influences may be common to the climates of both continents, the climate of A. is subject to two peculiar influences—that continent's prolongation south ward, and its backbone of mountains. With respect to the former point, A. advances at least 20" further southward than Africa—fully more than half the interval between the latter and antartic ice; so that the southern breezes which, in summer, bring freshness and delight to the cape of Good Hope, waft cold and misery to cape Horn. Two of Cook's people, on his first voyage, were frozen to death in Tierra del Fuego towards the end of Jan.—in a month corresponding with our July, and in a latitude the same as that Of Edinburgh. The backbone of mountains, again, that other point which peculiarly influences the climate of A., does its work in two ways. Throughout almost its entire course, its height arrests the passage of the clouds and rains. Within and about the tropics, these are borne from the e. by the trades; in the more temperate regions, they are brought from the w. by the prevailing counter-currents of air. But in either case, the windward slope of the mountain barrier is a fertile garden, the leeward slope a barren desert. In the more central plateaus, again, of Quito and Mexico, the various terraces present as many climates, and bring together, under the same parallel, all the tempera tures and energies of nature.
But there exist, more particularly in North A.., peculiarities of climate, which cannot, perhaps, be referred to any known cause. On the opposite sides, for instance, of the great water-shed between the gulf of Mexico and Hudson's bay, antagonistic results are said to show themselves in winter. On the northern side, the climate is understood to improve as one advances westward, the Saskatchewan, though in a considerably higher latitude, opening earlier in spring than the St. Lawrence; whereas, on the southern side, ice forms in New Orleans, at the mouth of the Mississippi, strong enough to bear half-grown boys, a thing wholly unprecedented on the corresponding parallel of the Atlantic shore. Even in summer, at least on the northern side of the water-shed in ques tion, something of a similar change of climate has been observed for maize, which, in Quebec, is a precarious crop, even on the international line of regularly ripens, in Red river settlement, which, besides 5° more of latitude, is at least 1000 feet higher above the level of the sea.
With respect to that portion of A. which is best known, a popular misapprehension generally prevails as to the steadiness of its climate in any given season of the year. The Canadian summer, for instance, is supposed to be an unbroken period of tropical heat; and the Canadian winter to be, in its turn, an unbroken period of hyperborean cold. Now, in both directions, this is a great mistake. The summer of Bntish A. is often tropical, and its winter often hyperborean, the extreme ranges of the thermometer, accord ing to the experience of credible informants in localities to the s. of London, sometimes
being in one and the same year, 104" F. above zero, and 52' below it. But this difference of Ng°, which is measured probably by an Interval of six months, is far less remarkable than the differences which a few days may bring forth. The highest range occurred within four days after parlor-fires had been given up; and the lowest fell on a day which, a year or so before, had been marked by a powerful thaw. In the city of Montreal Itself, 36 hours, or less, have sometimes exhibited a difference, up or down, of 60" F. in winter; and even in summer, whether in Quebec or in the north-west one can seldom reckon on any other month than July as free from night-frosts. In this respect, the Canadian climate may be taken as a sample of the climate of •North A. in general, extreme ranges of temperatures as prevailing respectively in summer and winter, being naturally attended by more or less considerable vicissitudes in each individual season.
In the tropical regions, however, of A., whether central or southern, a singular uniformity of temperature does exist on each of the various telTaCeS of the mountain chain. The same parallel, as has been already mentioned, presents at once the torrid, the temperate, and the frigid zones. Such a view of the matter, however, is, to a certain extent, deceptive, for in not one of the three cases are the vicissitudes of the respective zones, properly so called, found to show themselves. Each level is said to be so steady in its temperature as to enfeeble and enervate the inhabitants through the monotony even of that which is in itself good; and in such cases, the salutary prescription is to ascend or to descend, for a time, from one terrace to another.
Ilydrography.—With the backbone of mountains as the principal water-shed of A., the rivers on opposite, sides of the continent arc still more different than the climates. Excepting in Central A., the difference in question is enormous. Even in North A., where it is less than in South A., the contrast is sufficiently striking. On the w. side of the Rocky mountains, the only streams worthy ofthotice in such a summary as this are the Colorado, which flows into the head of the gulf of California; the Sacramento, which enters the harbor of San Francisco; and the Columbia, which empties itself into the open ocean—three rivers which, if compared with the waters of the opposite coast, are, in practical value, inferior singly to the Hudson, and to the Rio Bravo• del Norte. On the e. side, however, there exist rivers to which the Rio Bravo del Norte and the Hudson are but as brooks. To begin with the extreme n.: the Mackenzie, besides draining a large basin on its own side of the Rocky mountains, draws from beyond them two of its principal feeders, the Peace and the Liarde, burying itself, however, under the perennial ices of the Arctic ocean, Passing, without further notice, the Coppermine and the Fish river, of both which the interest is purely historical in connection with arctic discovery, we come to the Nelson, which brings down to Hudson's bay the Win nipeg and the Red river, two streams bordering respectively on the head-waters of the' St. Lawrence and the Mississippi, and also the two branches of the Saskatchewan, which all but touch the sources of the Columbia and the Missouri. Next in order is that long alternation of mighty river and mightier lake—that reservoir of half the life-blood of the earth--which, under the name of the St. Lawrence, gradually becomes a sea. South of the St. Lawrence, along the coast, we meet the Atlantic streams of New Brunswick and the United States, all of them valuable beyond their magnitude, and most of them connected, more or less closely, with the Alleghanies—the St. John, the Penobscot, the Connecticut, the Hudson, the Delaware, the Susquehanna, and the Potomac. Round into the gulf of Mexico, and we reach, besides many second-rate rivers in either direction, perchance the most important stream on the face of theglobe—a stream which, after uniting the Mississippi and the Missouri under the name of the former, receives on the right the Arkansas and the Red river, and on the left the Ohio, enriched, as it is, with the tributes of the Wabash and the Tennessee.