PHYSICAL CLIMATE. 489 



" In the country around there reigns an extraordinary degree of heat, the rays of the 

 mid-day sun striking directly on the south side of the mountain, while on its northern 

 side the valley of the Araxes preserves to a late season of the year the heat received from 

 the slopes of the Gorkchai mountains. In July and August the people fly from the 

 sultriness of the plain a sultriness which did not allow me, in the latter half of October, 

 to make any exertions out of doors in my usual clothing. At the end of that month the 

 thermometer still stood at 68 Falir. This excessively hot air continually ascends during 

 the summer up the sides of Ararat, warming its soil, and encroaching uninterruptedly on 

 its snows. In this way alone can I explain the great heat which allowed me, in the latter 

 end of September (old style), to spend two nights on bare rocks in the open air, without 

 a pelisse, and at the height of 13,800 feet above the sea. If to the circumstance of the 

 warm streams of air rushing up the sides of Ararat the greater part of the year we add 

 the isolated position of that mountain, the icy head of which is the only one in a very 

 wide tract that rises to a great height above the surrounding country, and which is, 

 therefore, of course, less able to resist the influx of warmth from below, than a more 

 widely extended mass of snow, such, for example, as occurs in the Alps, we can explain 

 satisfactorily enough the extraordinary height of the snow limits on Ararat, which, 

 according to my observations, are 14,080 feet above the level of the sea." 



From this effect of elevation upon temperature it is obvious that a country may have 

 all the varieties of climate within a very scanty area ; and accordingly, in several parts 

 of the torrid zone, an unfortunate geographical position is compensated by a happy 

 physical contour. The low coasts of Mexico, and the table-land nearly 9000 feet above 

 the sea, with its ridge of lofty peaks, of which Popocatapetl and Orizaba rise above the 

 snow-line, exhibit a striking example of a hot climate in close contiguity to one mild and 

 equable, and to another bordering upon arctic rigour. The hot regions, tierras calientes, 

 include the country along the eastern and western shores under the elevation of 2000 

 feet, where the mean temperature is about 77, and sugar, indigo, cotton, and bananas 

 flourish luxuriantly. Above these are the temperate regions, tierras templadas, which 

 lie along the slopes of the mountains at an elevation of from 2000 to 5000 feet. Here 

 the yellow fever, the scourge of the low grounds, is unknown ; and the mean heat of the 

 year is from 68 to 70. The traveller enjoys a genial air, and encounters the oaks, 

 cypresses, pines, tree-ferns, and the cultivated cereal plants of Europe. He next arrives 

 at the cold regions, tierras frias, which include the table-lands and the mountains above 

 5000 feet. On the borders of this zone the climate is still pleasant, but beyond the 

 elevation of 8000 feet it becomes severe, and gradually assumes the character of the 

 polar latitudes. 



Switzerland, in a similar manner, exhibits a variety of climates within the area of a 

 tew square miles, with the vegetable productions peculiar to each, as the effect of its 

 surface-elevations and irregularities. The Valais, one of the cantons, displays this 

 diversity very remarkably. In that narrow and deep longitudinal valley, the extremes 

 of temperature occur at a trifling distance from each other, the cold of Iceland and the 

 heat of a Sicilian summer ; and while in some of its inhabited parts fruit will not ripen, 

 in others the wild asparagus is seen to grow, and the almond, the fig, and the pomegranate 

 attain the greatest perfection. This high temperature arises from its lofty mountain 

 walls preventing the free passage of the air, and reflecting from their sides the heat they 

 receive from the rays of the sun, which impinge upon them more directly than on a level 

 surface ; and hence the singular fact has been witnessed, in an elevated valley of Mont 

 Blanc, of the temperature in the centre being so much increased by reflection, that the 

 spot has been covered with flowers and verdure in the midst of perpetual snows and 

 glaciers. Vines grow in the Valais to the height of 2380 feet above the level of the sea ; 



