8 Meteorological Observations made in 



the dry season at 88° -4, we have a yearly mean of 84^-7, which 

 is probably the extreme, or something beyond it. There is no 

 doubt it is in the plains of the interior we find the greatest heat 

 during the dry season. In the level country, called the valley of 

 Upar, betwixt the mountain ridges of Santa Marta and Ocana, I 

 fonnd the thermometer in the shade several times above 100°, and 

 once as high as 108°. The average of nineteen observations 

 made at different points of this district is 89° -9 ; but we must 

 allow a considerable decrease during the months when the soil is 

 covered with thick vegetation, and dienched by continual rains. 

 As a general mean of the interior, at small elevations, we may 

 take 80° -67, or nearly that of Cumana. 



3. The temperate mountain region lies nearly betwixt the ele- 

 vations of 3,000 and 7,000 feet. Below this may be considered 

 as a hot climate, such, for instance, as Valencia and the valleys of 

 Aragua in Venezuela, the height of which is from 1,500 to 2,000 

 feet, and its mean temperature 78°, or 0°-24 above that of Guay- 

 aquil on the Pacific ; but the soil, stripped by cultivation of its 

 ancient forests, imbibes freely the solar rays, which are besides 

 reflected from the rocky elevations which every where surround 

 the cultivated districts. The temperature of Caraccas (elevation 

 2904 feet) was fixed by Humboldt in his Essay De Disfributione 

 Geogro.phica Plantarum, p. 98, at 69° -6 ; but in his Personal 

 Narrative, b. iv, c. xii, p. 460, he considers 17° -2 of Reaumur = 

 70°. 40 of Fahrenheit, nearly as the true yearly mean. My own 

 observations during a residence of some months give 7i°'40. 

 The preference would be certainly due to Humboldt's calcula- 

 tion, but for some collateral circumstances deserving attention. 

 I heard it generally remarked in the city, that the seasons had 

 grown hotte?' since the earthquake of 1812. It would be difficult 

 to explain how the temporary evolution of volcanic gases, sup- 

 posing 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 phenomenon most 

 impressed on the imagination of the inhabitants. On looking 

 over Humboldt's collection of observations for December 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° -5, and on one occa- 



