other, and receiving the same degree of heat from the sun, we shall see that the sea is colder than the land during the day, and warmer during the night... In the same way, taking the different seasons of the year, in summer the sea is colder than the land, in winter it is warmer. It preserves the mean temperature, while the land experiences the extremes. It tends to soften all the differences, and to establish uniformity of climate. The sea climate, then, is equable; it is also moist, and the sky often cloudy and rainy, in the high latitudes. The land climate is excessive, with violent changes, generally dry, and the sky usually clear. It follows that the astronomical climate - that which is dependent on the latitude is greatly modified by the presence or absence of the sea; and the distribution of heat through the year, for any place whatever, depends in no small degree on its proximity to, or its distance from, the ocean, and the consequent prevalence of the winds which blow from it. Who does not see the powerful influence which such differences in the climatic conditions must exercise on all organised beings, and on vegetation in particular? While in green Ireland the myrtle grows in the open air, as in Portugal, without having to dread the cold of winter, the summer sun of the same climate does not succeed in perfectly ripening the plums and the pears, which grow very well in the same latitude on the continent... On the coasts of Cornwall and Devon, shrubs as delicate as the laurel or the camellia, are green through the whole year in the gardens, in a latitude at which, in the interior of the continents, trees the most tenacious of life can alone brave the rigor of the winters. On the other hand, the mild climate of England cannot perfectly ripen the grape, almost under the same parallel as the slopes which produce the delicious wines of the Rhine... At Astracan, on the northern shore of the Caspian, Humboldt says the grapes and fruits of every kind are as beautiful and luscious as in the Canaries and in Italy; the wines there have all the fire of those of the south of Europe; while in the same latitude, at the mouth of the Loire, the vine hardly flourishes at all. And yet, to a summer capable of ripening the southern fruits, succeeds a winter so severe, that the vine-dresser must bury the stock of his vines several feet in the earth, if he would not see them killed every year by the cold...It may be remembered that a part of the Russian army despatched for the conquest of Khiva- the region situated to the south of the sea of Aral-perished under the snows by cold of 20° below the zero of Fahrenheit, in a country situated under the same parallel as the Azores, where there reigns a perpetual spring; and where, in the midst of winter, the vegetation and the flowers display their most brilliant colours...It is in climates like that of Central Russia, that the camel, the inhabitant of burning deserts, and the reindeer of the frozen regions, meet together, and that nature seems to have brought together the climate of the poles and of the tropics. On man himself the influence of a moist and soft climate makes itself felt, by a relaxation of the tissues and a want of tonic excitement. The insular Polynesians, as those of Tahiti and others, exhibit the mild, facile, and careless character which seems to be naturally the result of such a climate. The continental climate does not give to the vegetation an appearance of such exuberance, but the variety of the soil, the frequent alternations of plains, table-lands, mountains, valleys, and of different aspects, secure to it an almost infinite variety of different species and forms... The animals are more vigorous and larger, the species more numerous, the types more varied. The lion, the tiger, the elephant, all the kings of the brute creation, have never lived elsewhere than on the continents, or on continental islands... Man himself is more animated, more active, more intelligent, and endowed with a stronger will; in a word, life is more intense, and raised to a higher degree, by the variety and movement impressed upon it by the contrasts that form the very essence of this climate. The ocean is the indispensable handmaid of the land. The sun, the great awakener of life, shoots his burning rays every day athwart the face of the waters. He causes the invisible vapors to rise, which, lighter than the air itself, unceasingly tend to soar into the atmosphere, filling it and constituting within it another aqueous atmosphere...In their ascending movement, they encounter the colder layers of the higher regions of the atmosphere, which have a cooling influence. They are condensed in vesicles, which become visible under the form of clouds and fogs. Then, borne along by the winds, whether invisible still or in the state of clouds, they spread themselves over the continents, and fall in abundant rains upon the ground which they fertilise... All the portion of the atmospheric waters not expended for the benefit of the plants and of the animals, nor carried off anew into the atmosphere by evaporation, returns by the springs and rivers to the ocean whence it came. Thus the waters of the ocean, by this ever renewed rotation, spread themselves over the lands; the two elements combine, and become a source of life, far richer and much superior to what either could have produced by its own forces alone. THE RAINS AND THE WINDS. The temperature, the winds, and the rain, having an intimate connection, each with the others, and playing alternately the part of cause and effect, the earth may conveniently be divided into two great zones: the one, that of periodical rains, or of the tropical regions; the other, that of variable rains, or of the temperate regions. In the equatorial regions, where the course of temperature and winds is regular, that of rains is equally so; and instead of seasons of temperature, which are there unknown, the inhabitants draw the distinguishing line between the dry and the rainy seasons. Whenever a trade-wind blows with its wonted regularity, the sky preserves a constant serenity and a deep azure blue, especially when the sun is in the opposite hemisphere; the air is dry and the atmosphere cloudless ... But in proportion as the sun approaches the zenith of a place, the trade-wind grows irregular, the sky assumes a whitish tint and becomes overcast, clouds appear, and sudden showers accompanied with fierce storms ensue. Showers occur more and more frequently, and turn at length into floods of rain, inundating the earth with torrents of water... The air is at this time so damp that the inhabitants are in an incessant vapor bath. The heat is heavy and stifling, the body becomes dull and enervated; this is the period of those epidemical fevers that destroy so great a number of the settlers who have come from the temperate zones vegetation puts on a new freshness and vigor; the desert itself becomes animated, and is overspread for a time with enchanting verdure, which furnishes pasture to thousands of animals. Shortly, however, the sun, passing on his annual progress, advances and pours down his vertical rays upon other places; the rains diminish, the atmosphere becomes once more serene, the trade-wind resumes its regularity, and the heaven shuts its windows again until the following season. But Such is the normal course of the tropical rains. They fall on each spot during the passage of the sun through the zenith. The heat is then so violent that the ascending current of air neutralises the horizontal trade-wind. It hurries the vapors to the heights of the atmosphere, and to the upper limit of the trade-wind, where they are condensed and fall down in a deluge of rain. Now as the sun passes and repasses from one tropic to the other, it follows that there is in most intermediate places a twofold rainy season; the two periods of rain being more or less closely connected in point of time, according to the distance of the place from the tropic. We may conceive the prodigious effect such violent showers must produce upon the rivers. We can understand the secret of the overflowings of the Nile, once so mysterious, which are due to the circumstance, that the region of its sources receives the tropical rains. Floods of forty feet and upwards are frequent at this season in the great rivers of South America; the Llanos of the Orinoco are for a time changed into an inland sea. The Amazon inundates the plains through which it flows for a vast distance. The Paraguay also forms lagoons, more than three hundred miles in length, which ooze away and evaporate during the dry season. The quantity of water contained in the tropical atmosphere in the condition of transparent vapors, is always considerable. It is in proportion to the heat, which, being always very great, augments its capacity to a very high degree. Even under the most serene sky, the air is still abundantly provided with vapor. It is this invisible water which, being absorbed by the plants and taken up by their large leaves, produces the vigorous vegetation, and causes the eternal verdure that fills us with astonishment, under a sky devoid of rain, and cloudless during more than half the year; while in our climate, from the failure of rain for a few weeks only, we see all verdure languish, and all the flowers perish for the lack of moisture. The winds of the ocean striking the coasts of the continents and moistening them with their waters, penetrate into the interior, transport thither the vapors with which they are charged, and spread life and freshness on their path. But in proportion as they advance on their continental journey, they become more and more sparing of these beneficent waters; their provision at length becomes exhausted, and if the way is too long, that is, if the continent is too extended, — they arrive at its interior, arid and parched, with the characters of a land wind. --- However, there are circumstances which disturb or rather modify the general law; these circumstances are the form of relief of the land, the mountain chains and the plateaus, and their position in relation to the damp winds. A wind loaded with vapor may pass over vast continental plains without dissolving into rain, because the temperature over a plain may remain the same through long spaces, or perhaps be higher than that of the sea wind which crosses it. There is then no agency to condense the vapors. We have an example of this in the Etesian winds, which bear the vapors of the Mediterranean into the Sahara. They have no sooner passed the threshold of the desert, than the dry and hot air dissipates every cloud. But it is not the same when the moist winds meet elevated objects, such as chains of mountains and high table-lands, in their transit. Forced to ascend the mountain sides, they are uplifted into the colder regions of the atmosphere; they feel the diminished pressure of the air, their expansion further assists the cooling process, and the air loses that capacity for holding the same quantity of vapors as before... The vapors are condensed into clouds, which crown the summits of the mountains, hang upon their sides, and soon melt into abundant rains. If the sea wind passes over the chain, it descends the opposite side, dry and cold; it has lost all its marine character. The mountain chains are then the great condensers placed here and there along the continents, to rob the winds of their treasures, to serve as reservoirs for the rain waters, and to distribute them afterwards, as they are needed, over the surrounding plains... Their wet and cloudy summits seem to be untiringly occupied with this important work. From their sides flow numberless torrents and rivers, carrying in all directions wealth and life. Every system of mountains becomes the centre of a system of irrigation, which gives to its neighbourhood one of its choicest gifts... From the operation of this power of condensation, there falls on the summits of the mountains more water than on their slopes, and at their foot there falls more than on the adjoining plains... Besides, the side of the chain exposed to the sea winds receives a quantity of rain much beyond that which falls on the opposite side; so that the great systems of mountains not only divide terrestrial spaces, but separate different and often opposite climates. Guyot's Earth and Man. MOUNTAINS. INFERIOR hills ordinarily interrupt, in some degree, the richness of the valleys at their feet; the grey downs of southern England, and treeless coteaux of central France, and grey swells of Scottish moor, whatever peculiar charm they may possess in themselves, are at least destitute of those which belong to the woods and fields of the lowlands...But the great mountains lift the lowlands on their sides. Let the reader imagine, first, the appearance of the most varied plain of some richly cultivated |