Ebbing and Flowing Weil. 367 
water rises again in the notch, so soon as the 
influx into the trough begins to be more co- 
pious. The reciprocations of the spring are 
easily observed by this contrivance ; and they 
‘appear to be very irregular both in respect 
of duration and magnitude. For the interval 
of time betwixt any two succeeding flows, is 
sometimes greater, and at other times less, 
than a similar interval which the observer 
may happen to take for his standard of com- 
parison. The rise of the water in the cis- 
tern, during the time of the well’s flowing, is 
also equally uncertain; for it varies from one 
inch, to nine or ten inches, in the course of 
a few reciprocations. It is necessary to re- 
mark on the present occasion, that the spring 
discharges bubbles of air, more or less’ copi- 
ously into the trough; these appear in the 
greatest abundance at the commencement of 
a flow, and cease during the ebb, or at least 
issue from the rock very sparingly at that 
time. In fact the appearance and disappear- 
ance of these bubbles, are circumstances 
equally inconstant with the rise and fall of the 
water. . 
The irregularities exhibited by the ebbing 
and flowing weli, during my short visit, di- 
minished the respect which I formerly had for 
the popular theory, more especially when consi- 
