The rivers of the Castiles are of less importance than might be supposed from a look at a map, for, owing to a paucity of rain, they are not navigable. The moisture carried eastward by the winds is for the most part precipitated upon the {383} exterior slopes of the mountains, only a small proportion reaching the Castilian plateaux. Evaporation, moreover, proceeds there very rapidly, and if it were not for springs supplied by the rains of winter there would not be a single perennial river.[138]

Of the three parallel rivers, the Duero, the Tajo, and the Guadiana, the latter two are the most feeble, for the supplementary ranges of the Sierras of Gredos and Guadarrama shut off their basins from the moisture-laden winds of the Atlantic. Yet, in spite of their small volume, the geological work performed by them in past ages was stupendous. Both find their way through tortuous gorges of immense depth from the edge of the plateaux down to the plains of Lusitania. The gorge of the Duero forms an appropriate natural boundary between Spain and Portugal, for it offers almost insurmountable obstacles to in­ter­com­mu­ni­ca­tion. The more considerable tributaries of the Duero—such as the Tormes, fed by the snows of the Sierra de Gredos; the Yéltes; and the Agueda—likewise take their course through wild defiles, which may be likened to the cañons of the New World. The Tajo presents similar features, and below its confluence with the Alberche it enters a deep defile, hemmed in by precipitous walls of granite.

The Guadiana passes through a similar gorge, but only after it has reached the soil of Portugal. The hydrography of its head-streams, the Giguela and Záncara, which rise in the Serranio of Cuenca, offers curious features; but, as they are for the most part dry during summer, the bountiful springs known as the ojos, or “eyes,” of the Guadiana are looked upon by the inhabitants as the true source of the river. They are three in number, and yield about four cubic yards of water a second. These springs are popularly believed to be fed by the Ruidera, which, after having traversed a chain of picturesque lakelets, disappears beneath a bed of pebbles; but Coello has shown that after heavy rains this head-stream of the Guadiana actually reaches the Záncara.

The climate of the Castilian plateaux is quite continental in its character. The prevailing winds of Spain are the same as in the rest of Western Europe, but the seasons and sudden changes of temperature in the upper basins of the Duero, the Tajo, and the Guadiana recall the deserts of Africa and Asia. The cold in winter is most severe, the heat of summer scorching, and the predominating winds aggravate these features. In winter, the norte, which passes across the snow-covered Pyrenees and other mountain ranges, sweeps the plains and penetrates through every crevice in the wretched hovels of the peasants. In summer a contrary wind, the solano, penetrates through breaks in the Sierra Nevada and Sierra Morena, scorches the vegetation, and irritates man and animals. The climate of Madrid[139] is typical of that of most of the towns of Castile. The air, though pure, is exceedingly dry and penetrating, and persons affected with diseases of the throat run considerable risk during their period of acclimation. “The air of Madrid does not put out a candle, but kills a man,” says a proverb, and the climate of that city is described as “three months of winter and nine of hell.” True, in the {384} time of Charles V., Madrid enjoyed the reputation of having an excellent climate, and it is just possible that its deterioration may be ascribable to the destruction of the forests.

[Μ]

Fig. 142.—THE STEPPES OF NEW CASTILE.

According to Willkomm. Scale 1 : 1,500,000.

The greatest variety of plants is met with if we ascend from the plains to the summits of the mountains, but taken as a whole the vegetation is singularly monotonous, for the number of plants capable of supporting such extremes of temperature is naturally limited. Herbs and shrubs predominate. The thickets in the upper basin of the Duero and on the plateaux to the east of the Tajo and the Guadiana consist of thyme, lavender, rosemary, hyssop, and other aromatic plants; on the southern slopes of the Cantabrian Mountains heaths with small pink flowers predominate; vast areas in the mountains of Cuenca are covered with Spanish broom, or esparto; and saline plants abound in the environs of Albacete. These regions are generally described as the “Steppes of Castile,” though “deserts” {385} would, perhaps, be a more appropriate term. For miles around the village of San Clemente not a rivulet, a spring, or a tree is met with, and the aspect of the country throughout is exceedingly dreary. The interminable plains of La Mancha—the “dried-up country” of the Arabs—adjoin these steppes in the west, and there corn-fields, vineyards, and pasture-grounds alternate with stretches of thistles, and the monotony is partly relieved by the windmills, with their huge sweeps slowly revolving overhead. Estremadura and the slopes of the Sierra Morena are principally covered with rock-roses, and from the summit of some hills a carpet of jarales, bluish green or brown, according to the season, extends as far as the eye reaches, and in spring is covered with an abundance of white flowers resembling newly fallen snow.