made in Colombia between the years 1820 and I8S0. 155 



since the earthquake of 1812. It would be difficult to ex- 

 plain how the temporary evolution of volcanic gases, sup- 

 })osing such to have taken place, could operate any permanent 

 change on the surrounding atmosphere; yet other causes may 

 have produced an effect falsely ascribed to the phaenomena 

 most impressed on the imagination of the inhabitants. On 

 looking over Humboldt's collection of observations for De- 

 cember and January 1799, we find the thermometer seldom 

 rise to 75°, and often sink to 59°, so that the mean of these 

 months is about 68°. During the same months in 1821 the 

 daily range was from 65° to 76°. I never observed it lower than 

 61^°, and on one occasion at 5 a.m. it stood at 71°. The 

 mean of these two months is 70°'21, or 2°'21 higher than the 

 estimate of Humboldt. The clearness and beauty of the sky 

 during almost the whole period of my residence is also a cir- 

 cumstance opposed to Humboldt's " Ccelum saepe nubibus 

 grave quae post solis occasum terras appropinquant." {De 

 JDistrib, Geog. PL, p. 98.) I remember but once to have seen 

 a fog in the streets of the city. Future observations will show 

 whether any change of climate has really taken place, or 

 whether the differences observed be only such variations as 

 may be frequently remarked in the same places between one 

 year and another. The mean of the whole temperate moun- 

 tain region may be reckoned at 67°*80, that is if we limit 

 ourselves to the districts partially cultivated and inhabited. 

 The declivities of the Andes, still covered with vast and humid 

 forests, have probably their temperature proportionally lower. 

 Thus the village of Mindo, on the western declivity of Pi- 

 chincha, embosomed in humid forests, at 3*932 feet of eleva- 

 tion, has a medium temperature of 65°'5, the same with that 

 of Popayan. 



4. The elevated plains of the Andes between 8000 and 

 11,000 feet, on which were anciently united the most power- 

 ful and civilized indigenous nations beneath the dominion of 

 the Lipas of Tunja and Bogota, and the Incas of Quito, and 

 v/here the great mass of Indian population is still to be found, 

 have a general medium temperature of 59°*37, modified how- 

 ever by local circumstances, and particularly by the proxi- 

 mity of the nevados. Thus the village of Guaranda, placed at 

 the base of Chimborazo, though nearly 500 feet less elevated, 

 is at least l°-0 colder than the city of Quito, sheltered on 

 all sides by the ramifications of Pichincha. The city, again, 

 is above 1°*0 warmer than its suburbs on the plains of Aiia- 

 quito and Turupamba to the north and south. Riobamba is 

 about 200 feet below Quito ; yet its situation in an open plain 

 bordered by the snowy mountains of Chimborazo, Tungura- 

 gua, and La Candelaria renders the climate colder and more 



