16 Col. R. Wright's Meteorological Observations made 



give an annual mean of 76°-78, or l°'4-2 lower than the valley 

 of the Orinoco, and 6°*22 lower than that of the Magdalena. 

 The mean temperatureof the plains of Venezuela is reckoned 

 by Humboldt at SS'4 {De Distributione Geog. Plant, p. 92.); 

 yet several reasons may induce the belief that this calculation 

 is excessive. This illustrious traveller performed his journey 

 during the summer season, when the atmosphere is heated by 

 the reverberations from a parched and naked soil. Persons 

 who have resided near the Apure, state the climate in rainy 

 weather to be cool, and refreshed by a constant breeze. It is 

 only on the coast of the Pacific that the rainy season is the 

 period of the greatest heat, when the air is still, and undisturbed 

 by those electric explosions so common on the mountains and 

 in the interior. The observations I made at Varinas and San 

 Carlos, towards the beginning of the winter season, give a 

 mean of 81°; and averaging the dry season at 88°'4, we have 

 a yearly mean of 8 1^'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 Ocaiia, I found the ther- 

 mometer 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 co- 

 vered with thick vegetation, and drenched by continual rains. 

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

 take 8G°'67, or nearly that of Cumana. 



3. The temperate mountain region lies nearly betwixt the 

 elevations of 3000 and 7000 feet. Below this may be consi- 

 dered as a hot climate, such, for instance, as Valencia and the 

 valleys of Aragua in Venezuela, the height of which is from 

 1500 to 2000 feet, and its mean temperature 78°, or 0°-24' above 

 that of Guayaquil 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 

 everywhere surround the cultivated districts. The tempera- 

 ture of Caracas (elevation 2904 feet) was fixed by Humboldt 

 in his Essay De Distributione Geograj)hica Plantarum, p. 98, 

 at 69°*6; but in his Personal Narrative, b. iv, c. xii. p. 460, 

 he considers 17°'2of Reaumur = 70°-40 of Fahrenheit, nearly 

 as the true yearly mean. My own observations during a re- 

 sidence of some months give 71°"40. The preference would 

 be certainly due to Plumboldt's calculation, but for some col- 

 lateral circumstances deserving attention. I heard it generally 

 remarked in the city, that the seasons had grown hotter since 



