These geographical peculiarities of Spain, and particularly the existence of the great central elevation, when once attained are apt to be forgotten. The country rises from the coast, directly in the north-western provinces, and in some of the southern and eastern, with an intervening alluvial strip and swell: but when once the ascent is accomplished, no _real_ descent ever takes place--we are then on the summit of a vast elevated mass. The roads indeed _apparently_ ascend and descend, but the mean height is seldom diminished: the interior hills or plains are undulations of one mountain. The traveller is often deceived at the apparent low level of snow-clad ranges, such as the Guadarrama; this will be accounted for by adding the great elevation of their bases above the level of the sea. The palace of the Escorial, which is placed at the foot of the Guadarrama, and at the head of a seeming plain, stands in reality at 2725 feet above Valencia, while the summer residence of the king at _La Granja_, in the same chain, is thirty feet higher than the summit of Vesuvius. This, indeed, is a castle in the air--a château en Espagne, and worthy of the most German potentate to whom that element belongs, as the sea does to Britannia. The mean temperature on the plateau of Spain is as 15° Réaumur, while that of the coast is as 18° and 19°, in addition to the protection from cutting winds which their mountainous backgrounds afford; nor is the traveller less deceived as regards the heights of the interior mountains than he is with the champaigns, or table-land plains. The eye wanders over a vast level extent bounded only by the horizon, or a faint blue line of other distant sierras; this space, which appears one townless level, is intersected with deep ravines, _barrancos_, in which villages lie concealed, and streams, _arroyos_, flow unperceived. Another important effect of this central elevation is the searching dryness and rarefication of the air. It is often highly prejudicial to strangers; the least exposure, which is very tempting under a burning sun, will often bring on ophthalmia, irritable colics, and inflammatory diseases of the lungs and vital organs. Such are the causes of the _pulmonia_, which carries off the invalid in a few days, and is the disease of Madrid. The frozen blasts descending from the snow-clad Guadarrama catch the incautious passenger at the turning of streets which are roasting under a fierce sun. Is it to be wondered at, that this capital should be so very insalubrious? in winter you are frozen alive, in summer baked. A man taking a walk for the benefit of his health, crosses with his pores open from an oven to an ice-house; catch-cold introduces the Spanish doctor, who soon in his turn presents the undertaker. [Sidenote: THE PYRENEES]