22 FLUCTUATION S0FLE7EL 



To tlic facts here given I propose to add v(>ry little in the viay of a disrussion. 

 ])nring the observations, erabracin<j^ parts of three days, the barometer was lowest 

 at the commencement, on the 21st. There had been no recent storms. The 

 weather was close, foggy, and warm for the season and the latitude. From 4 

 o'clock and 50 minutes in the afternoon of the 21st to 9 o'clock in the evening, 

 the rise was from 29.440 to 29.600. After a drizzling, foggy night, and a scarcely 

 perceptible northerly breeze, the column stood about as it did the evening previous, 

 and so remained until 3 P. M. of the 22d. The movements of the water were not 

 marked till about this hour, when the wind, still continuing in the north, increased 

 slightly, and the mercury began to rise. 



On the morning of the 23d it was still higher, and the play of the waters very 

 lively, the wind continuing in the north. So long as the observations continued, 

 the nio\enients of the surface were slight in quantity, but rapid in time, with only 

 a slight wind. The barometer was all this time steadily rising. From 7 A. M. to 

 3 P. M. it rose from 29.640 to 29.870 inches. 



For several days following the 23d there were moderate gales on the Lake, and 

 rain. On the 28th of the month the regular autumn winds commenced, with snow. 

 The middle day (the 22d) showed more fluctuation of the barometer and less of the 

 water than either of the others. 



It is not easy to conceive of a change in the weight of the atmosphere that shall 

 be completed in an average period of ten minutes, and in some cases much less. Is 

 not the cause therefore still to be sought fori 



By my observations there is no apparent connection with storms, except thunder- 

 storms. That season of the year, and the kind of weather when thunder-gusts are 

 most frequent, with intervening calms and fogs, is most prolific of oscillations. 



There is a distinct class of movements due to the direct driving force of winds 

 that I shall notice below. For the consideration of those who wish to theorize 

 upon the flicts I have presented, 1 suggest that they turn their attention to the 

 agency of electricity. 



In May, 1855, the surface of Seneca Lake, as reported in the Geneva Gazette, 

 rose and fell during two entire days as often as once in ten to thirty minutes, 

 ranging through a vertical distance of five inches to two feet. The presence of 

 storms is not mentioned. Could a difference of barometrical pressure exist on 

 different sides of a narrow inland Lake only a few miles across 1 If so, can we rely 

 upon the barometer to obtain difference of elevation"? 



AVhile observing the influx and reflux at Eagle river, in July, 1855, the air was 

 frequently agitated by the usual detonations of lightning. Shocks in the atmo- 

 sphere which produce thunder, which stunned the ear, and cause walls and floors of 

 buildings to tumble, might also produce agitations of the surface of water. There 

 is physical force sufficient in the electricity of the atmosphere at all times to pro- 

 duce this effect; the difficulty occurs in applying it. Electrical movements may 

 be brought into existence by opposite conditions of the atmosphere which vests 

 ui)on the water and the surrounding shores, especially if there are adjacent 

 mountains. 



Vaiior is condensed by winds which meet with peaks or mountain crests, and 



