Qn the Seiches of the Lake of' Geneva. 297 



^l. This cause, which appears to be always acting, must be 

 rendered more powerful by local circumstances, which exist in a 

 remarkable degree on the Lake of Geneva, and in such a way 

 as to produce its maximum of effect at the neighbourhood of the 

 town, or the exit of the Rhone ; and that from that spot it con- 

 tinually diminishes, on the one side lo the confluence of the Arve 

 and the Rhone, and on the other to the widest expanse of the 

 lake, where it does not extend beyond a few lines. 



It is concerning the nature of this cause, as we believe, that 

 those naturalists have deceived themselves, who have attempted 

 to give explanation of the phenomenon ; and who, with a paucity 

 of observations, or rather without any accurate observations at 

 all, have assigned causes for the seiches which could never have 

 at all produced them. I do not here allude to the hypothesis 

 of Jallabert, who attributed them to the melting of the snows, 

 nor to that of Fatio, who imagined that a breeze of wind, act- 

 ing obliquely or vertically upon the surface of the waters at some 

 distance on the lake, thus retarded their flow ; but I allude more 

 particularly to the opinion of M. Bertrand, who thought that 

 the seiches were produced by certain electrical clouds, attract- 

 ing and repelling the waters, and alternately producing those 

 risings and fallings which constitute the phenomenon. But in- 

 dependent of the fact, that it is difficult to understand how the 

 power of an electrical cloud could attract or repel a mass of 

 water, it must be conceded, that if this were the true explana- 

 tion, there would never be seiches when the sky was not charged 

 with clouds, nor >vould there be any in winter or autumn ; nor 

 would they be so peculiar as they are on the lake of Geneva. 

 Besides, the water which was thus attracted and repelled by the 

 clouds, instead of remaining, as it often does, in a state of quies- 

 cence on the surface of the lake, would, on the contrary, be agi- 

 tated and repelled with violence : suppositions, these, which are 

 wholly at variance with the observations which we have detailed. 

 I do not deny that, in certain circumstances, electricity may pro- 

 duce some effects somewhat similar ; that electrical water-spouts, 

 for example, which are observed on the sea, and sometimes al- 

 so on the lake of Geneva, neither agitate its surface, nor elevate 

 and abase its waters; but the method in which these water- 

 spouts act, so far at least as it is known, has no resemblance to 



