The Lake of Geneva, in like manner, is liable to fluctuations of level amounting to from 1.95 to 2.60 meters, from the melting of the Alpine snows.
But besides these variations of level due to the variable quantities of water discharged into them by their affluents, many lakes of moderate dimensions are liable to rhythmical oscillations of level of short duration, which are, obviously, but produced by fluctuations in the supply of water.

It is to this kind of species of variation of level that our attention will be directed in the sequel.
This interesting phenomenon was first recognized in the Lake of Geneva; but was subsequently found to be common to all the Swiss lakes, as well as to those of Scotland.

It is, therefore, a general phenomenon, which may be observed in all lakes of moderate dimensions.

The inhabitants of the shores of the Lake of Geneva have long designated this rhythmical oscillation of the level of the water by the term of _Seiche_; and this designation has been adopted by scientific writers.
These _Seiches_ were first signalized in the Lake of Geneva in 1730, by Fatio de Duillier, who ascribed them to the checking of the flow of the waters of the Rhone on the shoal near Geneva by the force of the wind at mid-day.

Addison and Jallabert, in 1742, supposed them to be caused by sudden increments in the discharge of the affluents, due to the augmentation in the amount of snow melted after mid-day; or to the sudden increase in the flow of the Arve, checking the outflow of water by the Rhone.