On the Seiches of' the Lake of Geneva. S89 



indie other, it habitually ascended and descended at the same 

 instant on the opposite banks of the lake. Besides, the space 

 over which it moved in each minute is usually the same, with 

 some trifling exceptions, owing, it might br, to the observer. 

 And, finally, the sum-total of the rise and fall at the two stations 

 is, within a line or two, precisely the same. 



It is of importance to remark, that the kind of movement 

 might itself produce some anomalies ; for, as may be observed, 

 it was not accomplished in a regular and continuous way, but, 

 on the contrary, was effected rapidly, and as it were by fits and 

 starts. In the middle of a rapid rise, there would all at once 

 be a stop or a slow ascent, and then speedily another rapid rise. 

 Sometimes there was even a momentary fall in the middle of a 

 rise, or a rise in the middle of a fall ; and within the one minute 

 the water might both ascend and descend, one or more lines, so 

 that, in this case, it was only possible to mark the difference, and 

 this circumstance is no farther exhibited in the table than by 

 putting the letters r or y just as the rise or the fall, upon the 

 whole, predominated. 



In the 3d, 4th, 6th, 7th, and 8th observations, still maintain- 

 ing the station of Eaux-Vives, the author removed the other 

 one to points more and more distant from the town, sometimes 

 on the left bank, and sometimes on the right, till he reached 

 Genthod, at the distance of nearly five miles. He observed, 

 that as he removed towards the eastern extremity of the lake, 

 the amount of the seiches was less and less considerable : and 

 other observations which were subsequently made at Celigny, 

 ten miles from the town, confirmed the conclusion. 



In the 5th observation, he compared with the station of Eaux- 

 Vives another which was chosen on the Rhone, below the town, 

 , at the distance of nearly a mile from Eaux-Vives, following the 

 course of the stream, and he there found the oscillatory move- 

 ments much less. At the confluence of the Arve and the Rhone, 

 about a quarter of a mile further down, they could not be at 

 all detected. 



The 9th and lOth observations were more particularly design- 

 ed to demonstrate the influence of the atmosphere upon the 

 phenomenon. Unfortunately, however, during the year in which 

 the observations of Mr Vauchcr were made, the weather was 



