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Dr Anderson besides wrote many papers in periodical publications, and an account of Ancient Fortifications in the Highlands, read to the Society of Scotish Antiquaries.

 ANDES. The Encyclopædia contains such particulars relative to that amazing chain of mountains as could be gathered from the accounts of the early writers, and especially from the more precise descriptions given by the Academicians who were sent to Peru in 1736, to measure the length of a degree of the meridian under the Equator. But, since that period, Geography has made rapid advances, and Mineralogy, emerging from its obscurity, has risen to the rank of a science. The vast American Continent has been explored in different directions, by adventurous and intelligent travellers. Of these by far the most conspicuous for enterprise, accuracy of observation, and extent of scientific research, is the celebrated Humboldt, whose various discoveries in the regions of the New World have deservedly excited so much interest. The narrative, however, of this accomplished traveller is not yet completed, and we must content ourselves at present with combining the incidental sketches which occur in his other publications. We trust that we shall be enabled to give a fuller and more precise account of the Andes in the article.

The Andes are distinguished above all the known mountain-chains, by their immense extent and their prodigious altitude. They run almost parallel to the west coast of the southern Continent of America, at a mean distance of between 100 and 200 miles, rising in some places to the enormous height of 20,000 feet; and stretch from the mouth of the river Atrato, on the isthmus of Darien, in the latitude of 8 degrees north, as far as Cape Pilares, at the outlet of the Straits of Magellan, in the 53d degree of south latitude,—a range of at least 4200 miles. According to Humboldt, they send out, nearly at night angles to their colossal ridge, three dependent branches, called likewise Cordilleras by the Spaniards.

Of these secondary chains, the first and most northern is that of the coast of Venezuela, which is besides the highest and narrowest. With an irregular altitude, it bends eastwards from the Atrato, forming the Sierra of Abibé, the mountains of Cauca, and the high Savannahs of Folu, till it reaches the stream of Magdalena, in the province of St Martha. It contracts, as it approaches the Gulf of Mexico at Cape Vela; and thence extends to the mountain of Paria, or rather the Galley-Point in the island of Trinidad, where it terminates. This secondary chain attains its greatest known elevation where it rears the snowy summit, or Sierra Nevada, of St Martha and of Merida, the former being nearly 14,000, and the latter above 15,000 feet, in altitude. These insulated mountains, covered so near the equator with eternal snow, yet discharging boiling sulphureous water from their sides, are higher than the Peak of Teneriffe, and can be compared only with Mont-blanc. In their descent, they leave the Paramo or lofty desert of Rosa and of Mucachi; and on the west side of the lake Maracaybo, they form long and very narrow vales, running from south to north, and covered with forests. At Cape Vela, the mountain-chain divides into two parallel ridges, which form three confined vallies, ranging from east to west, and having all the appearance of being the beds of ancient lakes. These ridges, of which the northern is the continuation of the Sierra Nevada of St Martha, and the southern the extension of the snowy summits of Merida, are united again by two arms which seem to have been placed by the hand of nature, as dikes to confine the primeval collections of water. The three vallies thus enclosed are remarkable for their elevation above the sea, rising like steps one above another, the eastmost, or that of the Caraccas, being the highest. This plain was found by Humboldt to be elevated 2660 feet, while the basin of Aragua has only 1350 feet in height, and the Llanos, or reedy plains of Monai, spread within 500 or 600 feet above the level of the shore. The lake of the Caraccas appears to have forced a passage for itself through the quebrada, or cleft of Tipé, while that of Aragua has been gradually dissipated by a slow process of evaporation, leaving some vestiges of its former existence in pools charged with muriate of lime, and in the low islets called Aparecidas, The medium height of the Cordillera of the coast is about 4000 or 5000 feet; but its loftiest summit, next to the Sierra Nevada of Merida, is the Silla (or saddle) of the Caraccas, which was visited by Humboldt, and ascertained from barometrical measurement to have an elevation of 8420 feet. Farther to the eastward, the mountain-chain becomes suddenly depressed, especially its primitive rocks; the beds of gneiss and mica slate, meeting as they advance with accumulations of secondary calcareous substances, which envelope them completely, and rise to a great