made in Colombia bet-ween the years 1820 and 1830. 151 



known by the name of Paramitos, On the elevated plains we 

 find the showers more or less sudden and violent, according 

 to localities which give rise to a mixture of currents more or 

 less variably heated. Quito, for example, is situated on what 

 may be called a ledge of the lofty mountain of Pichincha, and 

 overlooks the valley of Chillo or Guaillapamba, furrowing the 

 adjacent table-land, in which the therujometer often rises to 

 80° in the shade. The encounter of portions of the atmo- 

 sphere thus variously heated produces showers as sudden and 

 heavy as those which generally distinguish tropical chmates. 

 On the slopes of the Cordillera the rains are generally vio- 

 lent, for the sam^ reason. 



Looking to the hygrometrical state of the atmosphere, as it 

 results from observations made on the table-lands of the 

 Equator and the coast of the Pacific, we find it to vary from 

 0° in the damp forests of Esmeraldas to 97°*1 on the elevated 

 plain of Cayambe; the experiments in both places being 

 made during June and July, the summer months both of the 

 coast and mountains. The average medium for the low-lands 

 is 23°*85 ; for the Cordillera 44°*36 of the hygrometer con- 

 structed upon Leslie's principle; but we are in want of suffi- 

 cient data for those elevations which approach the limit of 

 perpetual snow. To judge however from a small number of 

 observations made on the mountain of Cayambe, at 12,705 

 and 14',217 feet of elevation; and at the hut of Antisana at 

 14,520 feet, where the hygrometer was found to give 16°*5, 

 13°-9, and 30°-3, it would not seem that the dryness of the 

 atmosphere increases in ratio of the elevation, at least in the 

 neighbourhood of snowy mountains where a continual moi- 

 sture is exhaled, and heavy mists sweep over the soil towards 

 the evenings even of the fairest days. 



To estimate the general distribution of temperatures through 

 the vast territory of Colombia, we may conveniently consider 

 it as divided into five zones. 1. That of the level, or nearly 

 so, of the ocean. 2. That of small elevations, from 500 to 

 1500 feet. 3. That of the slopes of the Cordillera, from 

 2000 to 7000 feet. 4. That of the elevated plains, or table- 

 lands, from 8000 to 10,000 feet. 5. That of the Paramos^ 

 from 11,000 to the limit of perpetual snow. 



1. The degree of heat at or near the level of the ocean is 

 modified by a variety of local circumstances, which may be 

 ranged under the following heads ; Proximity of the sea ; of 

 great rivers or lakes ; of lofty ridges of mountains ; of ex- 

 tensive forests; of contiguous elevations, which impede the 

 circulation of air and produce reflected heat. The various 

 combinations of these circumstances may be considered as 

 affording a rule of the increase or diminution of temperature. 



