4 Meteorological Ohservatioiis made in 



On the elevated plains we find the showers more or less sudden 

 and violentj according to localities which give rise to a mixture 

 of currents more or less variably heated. Quito, for example, is 

 situ ited on what may he called a ledge of the lofty mountain of 

 Pichincha, and overlooks the valley of Chillo of Guaillapamba, 

 furrowing the adjacent table land, on which the thermometer of- 

 ten rises to 80"^ in the shade. The encounter of portions of the 

 atmosphere, thus variously heated, produces showers as sudden 

 and heavy as those which generally distinguish tropical climates. 

 On the slopes of the Cordillera the rains are generally violent for 

 the same reason. Looking to the hygrometrical state of the at- 

 mosphere, as it results from observations made on ilie table lands 

 of the equator and the coast of tlic Pacific, we find it to vary 

 from 0-* in the damp forests of Esmcraldas to OZ"^-! on the ele- 

 vated 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 constructed 

 upon Leslie's principle ; but we are in want of sufficient dala for 

 those elevations which approach to the limit of perpetual snow- 

 To judge, however, from a small number of obscrvaiions made 

 on the mountain of Cayambe at 12,705 and 14,217 feet of eleva- 



tion, and at the hut of Antisana at 14,520 feet, where the hygro- 



meter 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 neighborhood of snowy mountains, 

 where a continual moisture is exhaled, and heavy mists sweep 

 over the soil towards 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. 1st. That of the level, or nearly so, 

 of the ocean. 2nd. That of the small elevations, from 600 to 

 1,500 feet. 3rd. That of the slopes of the Cordillera, from 2,000 

 to 7,000 feet, 4th. That of the elevated plains, or table lands, 

 from 8,000 to 10,000 feet ; and 5ih, That of ihe paramos, from 

 11,000 feet to the Umit of perpetual snow. 



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



■ 



ified by a variety of local circumstauces, which may be ranged 

 under the following heads: proximity of the sea; of great rivers 

 and lakes ; of lofty ridges of mountains ; of extensive forests ; of 



