in diminishing the Qnmititij of Water in Rivers. 99 



crossing tlie steppe of Baraba, that he might reach Barnaoul 

 from Tobolsk, M. de Humboldt ascertained that the process of 

 desiccation was every where greatly augmented by the effects of 

 cultivation. 



Europe also possesses its lakes, and these we have still to 

 examine in relation to the subject before us. My own progress 

 through Switzerland was much too rapid to allow me sufficiently 

 to attend to the light these waters throw on this interesting 

 point. My regret, however, is the less severe, as fortunately 

 a most illustrious observer has left some valuable documents 

 which supply new proofs of the influence of cultivation upon 

 the diminution of the quantity of water in the district. 



Saussure, in his first researches concerning the temperature 

 of the Swiss lakes, examined those which are placed at the foot 

 of the lowest line of the Jura range. The lake of Neufchatel is 

 eight leagues long, whilst its greatest breadth does not exceed 

 two leagues. In visiting this lake, Saussure was impressed 

 with the conviction that its limits at an early period must have 

 been much more extensive ; for, says he, the great level mea- 

 dows, and the swamps which terminate at the south-west ex- 

 tremity, have undoubtedly been covered with its waters. The 

 lake of Bienne is three leauges long and one broad. It is se- 

 parated from that of Neufchatel by a succession of plains which, 

 to all appearance, wei-e formerly under water. The lake Morat 

 is also separated from Neufchatel by a level morass, which no 

 one doubts was formerly submerged. Formerly, then, says 

 Saussure, the three great lakes of Neufchatel, Bienne, and 

 Morat, were united in one great basin. In Switzerland, then, 

 as in America and Asia, the ancient lakes, which we may dis- 

 tinguish as the primitive ones, — those which occupied the lower 

 portions of the valleys, when the country was wild and unculti- 

 vated, have subsequently been separated into a certain number 

 of independent ones, by the drying processes to which it has 

 been subjected. 



I shall terminate my task by availing myself, in this discus- 

 sion, of the observations of Saussure upon the lake of Geneva. 

 This interesting object was, as it were, the spot from whence 

 the celebrated philosopher commenced his immense labours. 

 No one ever studied it more deeply than he did. 



g2 



