92 M. Boussingault on (he Effect qfclearmg Land 



longer continued, and the cultivated lands have fallen back into 

 their wild state, the waters having ceased to fall, and are now 

 very speedily assuming a decided rising movement. 



I shall now direct my remarks to another quarter, without 

 however leaving America, in which we find a climate analo- 

 gous to that of Europe, and where we traverse immense dis- 

 tricts producing the most valuable grains. I shall direct at- 

 tention to the higher lands of New Grenada, and to those ele- 

 vated valleys, from GOOO to 9000 feet above the level of the 

 sea, which enjoy, throughout the year, a temperature of from 

 58° to 62° Fahr. Lakes are frequent among the Cordilleras ; 

 I might easily dwell upon niany of these, but shall bring un- 

 der review only those which have been the subject of previous 

 observations. 



The village of Ubata is placed in the vicinity of two lakes. 

 It is an important fact that, sixty years ago, these two sheets 

 of water formed one only. The older inhabitants have obser- 

 ved the waters gradually diminish, and their shores extend 

 themselves year after year. Fields of corn, of the greatest fer- 

 tility, at the present time cover districts which thirty years ago 

 were completely covered with water. The falling of the mean 

 level of this lake will the more readily be credited by the 

 consideration, that an occasional fall of three or four inches 

 lays bare a great extent of surface. If we inquire in the 

 neighbourhood of Ubata of any of the old men, who in their 

 younger days were devoted to the chase, or if we examine 

 the records of any of the different parishes, no doubt will re- 

 main that numerous forests have been felled. The clearing 

 still goes on ; and it is equally certain that the retreat of the 

 water has not ceased, though it does not advance so rapidly as 

 it was wont to do. 



The lake of Fuquena, in the same valley, and to the east of 

 Ubata, deserves marked attention. By barometrical measure- 

 ments, made with the greatest care, I have found that its wa- 

 ters have precisely the same elevation as those of Ubata. It is 

 now nearly two centuries since this lake was visited by Don 

 Lucas Fernandes de Piedrahita, Bishop of Panama, to whom 

 we are indebted for the History of the Conquest of New Gre- 

 nada. This author, whose accuracy I have frequently had oc- 



