880 Observations on an 
perform the part of the inverted Siphon al- 
ready described, and exhibit the operations 
as well as the irregularities of the fountain 
in question. The same internal structure 
may be supposed to exist in Lay Well, near 
Torbay; but something is required im addi- 
tion to this simple apparatus to account for 
‘the casual reciprocation of Weeding Well, 
in Derbyshire: It is not a difficult. task 
to accommodate the theory to the description 
of this spring; but when we consider how 
imperfect such descriptions are commonly 
found to be, it appears more advisable to 
pass over this fountain in silence; until some 
accurate observer shall present the public 
with a correct and minute history of. its 
operations. | 
All parties allow, that reciprocating foun- 
tains flow from pools of water, concealed 
under ground; on which account it will not 
be very foreign to the tepic of the present 
essay, if I conclude it with a few remarks on 
the structure and formation of caverns, I 
have visited many caves in this part of Eng- 
land; all of which are situated in the strata 
of calcareous hills. They also appear to have 
been once filled with an argillaceous stone, 
of a less durable nature than the surrounding 
limestone. This supposition is corroborated 
