PANAMA, THE ISTHMUS OF (New Granada), constitutes the most eastern and the narrowest portion of .the long isthmus by which the two Americas are united. It extends, together with the province of Veragua, which is contiguous to it on the west, from 77 to 83° W. long., between 7° 20' and 10° N. lat. When measured along its curve the length from east to west is nearly 500 miles, but its width varies from 30 to 100 miles. Its area is nearly 30,000 square miles. The population was in 1853 estimated at about 140,000, of whom about 8000 were Americana, settlers, &c. ; 14,000 descendants of Spanish colonists; and the remainder needs, mulattoes, negroes, and native Indians.
Surface, Soil, Climate, &c.—It was formerly assumed in geographical works that the Andes of South America extended through the Isthmus, but this is now ascertained not to be the fact. [ANDES.] West of 77° 30' W. long. no range of mountains, nor even an isolated elevation of moderato height occurs, and the whole isthmus throughout has a summit level comparatively little elevated above the sea, though the surface of the country is a good deal broken. The low country extends westward for more than a hundred miles to the western extremity of Mending°, or San Bliss Bay. The average width of this part of the isthmus does not exceed forty miles, and opposite San Blas it contracts to less than thirty miles. The shores on both oceans are rocky, and the whole region appears to consist of an immense mass of rock. The rocks however are covered by a thick layer of vegetable mould, and are clothed with lofty forest-trees. The shores of the Caribbean Sea are difficult of access for large vessels, being lined with numerous small rocky islands called 'keys.' Two rivers drain the isthmus. They are called respectively Chucunaque and Chepo, and rise near 78° 30' W. long. The Cnucunuque runs east-south-east about eighty miles, and turning west by an abrupt bend falls into the Bay of San Miguel; the Carp°, or Balton°, runs west-north-west, and empties itself into the Gulf of Panamd., about twenty-four miles east of the town of Chepo, making a turn to the south. Both rivers are navigable for large river barges as far as the places where the great bend occurs.
With all the advantages which this region possesses from its great fertility and the vicinity of two great oceans and navigable rivers, it is thinly inhabited, and chiefly by a tribe of Indians, the Mandingoes, or San Bless Indians, who resist all attempts to penetrate into the interior, though they receive in a friendly manner the vessels which visit the coast. The small town of Chem above the bend of the river
of that name, is the most considerable settlement of the whites and negroes, but the inhabitants have little communication with their neighbours the Maudingoes. The country appears to be very unhealthy, owing to the swampiness of the soil and the consequent humidity of the atmosphere. This moisture of the air indeed maintains a most luxuriant vegetation, but the great quantity of vegetable matter, which is annually reproduced and decomposed, increases the miasma which exhales from a swampy soil under the influence of a vertical suu. At the western extremity of Mending° Bay some hills commence, which gradually attain the elevation of mountains, and extend in a continuous chain as far west as a line drawn across the isthmus from Navy Bay, or Port Liinones to the town of P11118.11A a distance of about fifty miles. These thlls advance close to the shores of the Caribbean Sea, where they surround the town of Puerto Velo, but they remain a few miles distant from the Pacific, and are separated from it by a level prairie destitute of trees. They occupy nearly the whole width of the isthmus, but are divided longitudinally into two ridges, between which lies the valley of the river Chagres. The southern ridge does not exceed 1000 or 1100 feet in height, but the northern rises much higher. These hills are generally covered with thick and almost impenetrable forests. The valley of the Chagres is rather narrow, but the river itself is navigable to a considerable extent. [Cas.aeto.1 The climate in this portion of the isthmus differs con siderably in the north and in the south. At Puerto Velo, on the northern coast, the rains are almost continuous, and generally descend in torrents, a circumstance which renders that place very unhealthy. At Panama and in the valley of the Chagres the seasons are pretty regular. From December to March inclusive rain scarcely ever falls. From April to June showers occur at regular intervals. As the season advances the ruin increases, and is incessant during July, August, September, and October. In November the nights are always rainy and cloudy, but during the days the sky begins to break. At Panama the thermometer in the rainy season is 82° during the night and 87° during the day. In the dry season the temperature rises to 90° and even 93° in the day-time, and the days are very sultry; but the land winds at night are cool, coming chiefly from the adjacent mountains.