On the Seiches of' the Lake of Geneva. • 291 



more, as it was opposed to the opinion of Saussure, who states 

 that the seiclies are observed at both ends of the lake. Hence 

 I took two journeys to the eastern extremity, to ascertain the 

 truth with my own eyes ; and I was never able to perceive va- 

 riations which extended beyond a Hne or two, even at the time 

 that corresponding observations in the neighbourhood of Geneva 

 shewed as many inches. The boatmen, and others who lived 

 on the shores, of whom I subsequently made inquiry, and who 

 were quite familiar with the phenomenon, as it is seen at Geneva, 

 have unanimously affirmed that they never observed any thing 

 similar, at either Evian, Villeneuve, or Vevey. 



It appears then certain, that the seicJies are at their maximum 

 in the narrowest part of the lake ; that they go on diminishing 

 to the distance of from three to six miles ; that thence to the 

 eastern extremity they are not seen to a greater extent than a 

 few hnes ; that their appearance, which may be at any season of 

 the year, is never more marked than during great atmospherical 

 vicissitudes, and that ihey almost disappear when the barometer 

 is high, when the north-east wind blows, and when the clouds 

 are uniformly spread over the sky. 



When I felt I had thus accomplished all that could be done 

 on the Lake of Geneva, I then thought of examining, with the 

 same object, the other lakes of Switzerland. I began with Zu- 

 rich. It was sufficiently large, and also, like Geneva, narrow at 

 one of its extremities. I had, moreover, in that Canton, a friend 

 who was as intelligent as obliging, to whom I could apply for 

 assistance. It was only, however, at my urgent solicitation that 

 he would comply with my request ; for he had previously inter- 

 rogated so many intelligent persons in the district, and their an- 

 swers were so uniform, that he was persuaded there was no such 

 occurrence on Lake Zurich. 



It happened, however, that when he was at one time examin- 

 ing, at the beginning of January, the time at which the margin 

 of the lake was frozen, he was astonished to see that the water 

 was alternately rising and falhng. At this time he witnessed 

 air-bubbles issuing from, and air rushing underneath, the ice. 

 Being, after this time, satisfied of the existence of the pheno- 

 menon, he began to examine it with much care and interest, 

 and the following is the result of his researches : — The move- 



