ese two divisions, with a third known as North Castile,
now rank as military districts or captaincies-general; but the term
"North Castile," which covers the northern extremity of Old Castile, is
not generally used. In 1833 Old Castile was divided into the provinces
of Avila, Burgos, Logrono, Palencia, Santander, Segovia, Soria and
Valladolid; while New Castile was similarly divided into Ciudad Real,
Cuenca, Guadalajara, Madrid and Toledo. The modern progress of commerce,
communications, &c. in these thirteen provinces is described in the
separate articles upon each of them.

Castile extends for about 300 m. from north to south, and 160 m. from
east to west. It consists of a vast central plateau, with an average
altitude of about 2500 ft. This plateau has a natural frontier of high
mountains on all sides, except on the borders of Leon and Murcia; it is
also bisected by the Sierra de Guadarrama and Sierra de Gredos, which
extend in a south-westerly direction across the central districts, and
form the dividing line between Old and New Castile. Geographically it
includes also the high plains of Leon, towards the north-west, and of
Murcia on the south-east. The existing frontier is marked on the north
by the Cantabrian Mountains (q.v.); on the east by the Sierra de la
Demanda with its offshoots, and by the Serrania de Cuenca; on the south
by the Sierra Morena; and on the west by various minor ranges which link
together the three more or less parallel chains of the Sierra de Gredos,
Sierra de Guadalupe and Sierra Morena. Three great rivers, the Douro,
which traverses Old Castile, with the Tagus and Guadiana, which
respectively drain the central and southern regions of New Castile, flow
westward into Portugal, and finally reach the Atlantic; while the Ebro,
which rises in the north of the kingdom, skirts the north-eastern
frontier on its way to the Mediterranean. These rivers are described
under their own names.

The climate of Old Castile is healthy, but liable to severe cold and
heat. Snow falls early and lies late in the mountains, and there is a
heavy rainfall in the north-west. New Castile has a still more rigorous
climate, for although the mean annual temperature is about 59 deg.
Fahr., the summer heat in the valleys is peculiarly oppressive, and the
highlands are swept by scorching or icy gales, laden with dust. The
rainfall rarely exceeds 10 in. in a year.

In both the Castiles the central plateau has a naturally fe