RECIPROCATING SPRINGS. 
191 
The observations which have been made on Mr. S wainston’s ac- Particular ex* 
cidental discovery, render an elaborate inquiry into the constitution P la nation of 
°fGiggle c wick well unnecessary. Nature may be easily supposed the Gig^es-^ 
to have produced an apparatus in the side of the hill, possessing wick well 
the mechanical properties of the reciprocating tub, and all the ^ated^thiory. 
phenomena will follow, which are so remarkable in this foun- 
tain. Let us imagine a reservoir to be concealed from view 
under the rocks, into which the stream of a subterranean brook 
falls, and beats part of its contents into foam by agitation. Let 
this cavity be connected with the externa) or visible basin ; by 
a narrow serpentine chink concealed in the imerposing strata ; 
and the reader must perceive, without farther explanation, that this 
conduit will perform the part of the in verted siphon already describe 
ed, and exhibit the operations, as well as the irregularities of the 
fountain in question. The same internal structure may be supposed 
toexist in Lay Well, near Torbay ; but something is required, in 
addition to this simple apparatus, to account for the casual reci- 
procation of Weeding Well, in Derbyshire. It is not a difficult 
task to accommodate the theory to the description of this 
sprhg ; but when we consider how imperfect such descriptions 
are commonly found to be, it appears more adviseable to pass 
over this fountain in silence ; untH some accurate observer 
shall present the public with a correct and minute history 
of its operations. 
All parties allow, that reciprocating fountains flow from pools ^ emar ks oa 
of water concealed under ground ; on which account it will Q f caverns, 
not be very foreign to the topic of the present essay, if I con- 
clude it with a few remarks on the structure and formation of 
caverns. I have visited many caves in this part of England, 
all of which are situated in the strata of calcareous hills. They 
also appear to have beeD once filled with an argillaceous stone, 
of a less durable nature than the surrounding limestone. This 
supposition's corroborated by the following fact : masses of 
'clay, mixed with gravel, are found scattered up and down these 
hollows j and as they are lodged in chinks from which they 
cannot be easily removed by water, I suppose them to be the 
remains of extensive beds, which formerly occupied these re- 
cesses in the calcareous strata. This argillaceous matter, which The mfiltra- 
choaked up the natural vaults of our limestone hills in early t!uoi?gi! c'al*a- 
ages, has been gradually worn away by a simple but powerful reous .dlls ha* 
agent. 
