154" Col. Francis Hall's Meteorological Observations 



tions give an annual mean of 76°'78, or l°-42 lower than the 

 valley of the Orinoco, and 6^*22 lower than that of the Mag- 

 dalena. The mean temperature of the plains of Venezuela 

 is reckoned by Humboldt at 88°-4 [De Distribute Geog. PL, 

 p. y2.) 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 Apur^ state the 

 climate in rainy weather to be cool, and refreshed by a con- 

 stant 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 com- 

 mon 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°*0; and averaging the 

 dry season at 88°*4, we have a yearly mean of 84°*7, which is 

 probably the extreme or something bej^ond it. There is no 

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

 heat during the dry season. In the level country called the 

 valley of Upar, between the mountain ridges of Santa Marta 

 andOcafia, I found the thermometer in the shade several times 

 above 100°, and once as high as 108'^*0. The average of nine- 

 teen observations, made at different points of this district, is 

 89^*09; but we must allow a considerable decrease during 

 the months when the soil is covered with thick vegetation, 

 and drenched by continual rains. As a general mean of the 

 interior at small elevations, we may take 80°*67j or nearly 

 that of Cumana. 



3. The temperate mountain region lies nearly between the 

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

 sidered as a hot climate : such for instance is 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°- 14 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 ele- 

 vations which everywhere surround the cultivated districts. 

 The temperature of Caraccas (elevation 2904 feet) was fixed 

 by Humboldt in his essay, De Distribute Geograph.PL, p. 98. 

 at69°'6 ; but in his Personal Narrative, b. iv. c. xii. (vol. iii. 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 71°'40. The preference would 

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

 lateral circumstances deserving of attention. I heard it ge- 

 nerally remarked in the city^ that the seasons had grown hotter 



