COTOPAXI, a mountain of the Andes, in Ecuador, South America, 35 m. S.S.E. of Quito, remarkable as the loftiest active volcano in the world. The earliest outbursts on record took place in 1532 and 1533; and since then the eruptions have been both numerous and destructive. Among the most important are those of 1744, 1746, 1766, 1768 and 1803. In 1744 the thunderings of the volcano were heard at Honda on the Rio Magdalena, about 500 m. distant; in 1768 the quantity of ashes ejected was so great that it covered all the lesser vegetation as far as Riobamba; and in 1803 Humboldt reports that at the port of Guayaquil, 160 m. from the crater, he heard the noise day and night like continued discharges of a battery. There were considerable outbursts in 1851, 1855, 1856, 1864 and 1877. In 1802 Humboldt made a vain attempt to scale the cone, and pronounced the enterprise impossible; and the failure of Jean Baptiste Boussingault in 1831, and the double failure of M. Wagner in 1858, seemed to confirm his opinion. In 1872, however, Dr Wilhelm Reiss succeeded on the 27th and 28th of November in reaching the top; in the May of the following year the same feat was accomplished by Dr A. Stübel, and he was followed by T. Wolf in 1877, M. von Thielmann in 1878 and Edward Whymper in 1880.
Cotopaxi is frequently described as one of the most beautiful mountain masses of the world, rivalling the celebrated Fujiyama of Japan in its symmetry of outline, but overtopping it by more than 7000 ft. It is more than 15,000 ft. higher than Vesuvius, over 7000 ft. higher than Teneriffe, and nearly 2000 ft. higher than Popocatepetl. Its slope, according to Orton, is 30°, according to Wagner 29°, the north-western side being slightly steeper than the south-eastern. The apical angle is 122° 30'. The snowfall is heavier on the eastern side of the cone which is permanently covered, while the western side is usually left bare, a phenomenon occasioned by the action of the moist trade winds from the Atlantic. Its height according to Whymper is 19,613 ft., and its crater is 2300 ft. in diameter from N. to S., 1650 ft. from E. to W., and has an approximate depth of 1200 ft. It is bordered by a rim of trachytic rock, forming a black coronet above the greyish volcanic dust and sand which covers its sides to a great depth. Whymper found snow and ice under this sand. On the southern slope, at a height of 15,059 ft., is a bare cone of porphyritic andesite called El Picacho, "the beak," or Cabeza del Inca, "the Inca's head," with dark cliffs rising fully 1000 ft., which according to tradition is the original summit of the volcano blown off at the first-known eruption of 1532. The summit of Cotopaxi is usually enveloped in clouds; and even in the clearest month of the year it is rarely visible for more than eight or ten days. Its eruptions produce enormous quantities of pumice, and deep layers of mud, volcanic sand and pumice surround it on the plateau. Of the air currents about and above Cotopaxi, Wagner says (Naturw. Reisen im trop. Amerika, p. 514): "On the Tacunga Plateau, at a height of 8000 Paris feet, the prevailing direction of the wind is meridional, usually from the south in the morning, and frequently from the north in the evening; but over the summit of Cotopaxi, at a height of 18,000 ft., the north-west wind always prevails throughout the day. The gradually-widening volcanic cloud continually takes a south-eastern direction over the rim of the crater; at a height, however, of about 21,000 ft. it suddenly turns to the north-west, and maintains that direction till it reaches a height of at least 28,000 ft. There are thus from the foot of the volcano to the highest level attained by its smoke-cloud three quite distinct regular currents of wind."
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)