CLIMATE. 
between the two oceans. These highlands terminate in paral- 
lel ridges of mountains, called the Cerro Peladro, which run 
from east to west along the 94th meridian, filling one-half the 
Isthmus, and uniting the table-land of Guatimala with that of 
Mexico. 
The range of mountains, the Cordilleras de la Huacamaya, 
Prieto, Masahuita, and others, whose extreme eastern limit is 
18° west of Washington, has a convexity towards Tehuantepec, 
and approaches within 20 or 25 miles of the Pacific shore. The 
range which lies eastward of this is further from the Pacific 
Ocean, and runs in a southeasterly direction. The result of these 
two chains of mountains is to form the Isthmus valley, with a 
slope four times as extensive towards the Gulf of Mexico as 
towards the Pacific. In this valley, which has a northeast 
direction, the river Coatzacoalcos, fed by other rivers, runs its 
contorted course-. The rivers which have their sources in the 
chains on both sides of the Isthmus, empty themselves into this 
common stream. On the southern side of these mountains, the 
proximity of the ocean, which sweeps inland with a crescentic 
margin, following the depression of the land, limits the river 
courses, and hence no large stream, fed by lesser ones, exists ; 
but each river rolls down the sandy plains, and empties itself 
into the lakes by its own channel, seven of which by this con- 
figuration of the ground, necessarily converge at their embou- 
chure within a space of thirty miles. An eighth, the Tehuante- 
pec Hiver, empties itself into the ocean at the Bay of Ventosa. 
The land slopes to either shore from the Cordillera de Prieto, 
having an average summit-level of 800 feet ; the descent occu- 
pying 28 miles to the Pacific, and about 110 miles to the Gulf 
of Mexico : this latter fall is through most of its extent very 
slight, the chief declivity being from the Almoloyo Eiver to 
the Jaltepec, the level of which is 75 feet above the sea-level : 
this last fall is accomplished in 75 miles, being scarcely one foot 
per mile descent from that river to the Mexican gulf. 
The result of this conformation is to give to the Isthmus the 
Ml benefit of the coast winds and rains from the north, which 
play over three-fourths of the breadth of land, and are only re- 
tarded from passing across its whole extent by the mountain land. 
