Ebbing and Flowing Well. 357 
‘ring, or any other small object, upon a dry 
* part of the basin. The water will rise 
* gradualiy to the mark, and afterwards cover 
“it. The fountain will, at length subside, so 
‘« as to leave the object dry ; and will be after- 
“ wards seen to retire slowly. If you pro- 
“long your stay, these alternate motions will 
“be repeated two or three times. Is this 
‘* singular appearance occasioned by air act- 
“img upon the outlet of the fountain; so as 
“to obstruct the current, when it enters by 
“the mouth of this channel, and, after its 
“escape to allow the water to issue more 
“freely? We know this to be the case 
“« with bottles, and all kind of yessels,, which 
“have narrow necks: for when they are 
*« placed in a position proper for discharging 
‘‘ their contents, the resistance of the air 
“ makes them guggle, and the liquor issues 
“from them in an interrupted stream. Or, 
“does this fountain partake of the nature of 
“the ocean? Is its current retarded at one 
“time, and accelerated at another by the 
“causes, which give rise to the flux and 
‘“‘ reflux of the sea ? Rivers we know are 
“driven back, when they fall into the sea 
“ against the wind and tide. May not some 
“ cause, in like manner, periodically obstruct 
“ the discharge of this fountain ? Or, are we 
