ISO 
a rocking 
stone forming 
a valve. 
Variation in 
the elder Pli- 
ny’s descrip- 
tion. 
Wet weather 
appears to af- 
fect these 
►springs. 
Another reci- 
procating 
spring in Do- 
dona. 
Strong foun- 
tain in West- 
phalia. 
RECIPROCATING SPRINGS, 
original 5 the latter of them, however, seems to have suggested 
the hypothesis of a rocking stone 3 which, acting on the prin- 
ciple of a valve, alternately opens and shuts the outlet of the 
spring 3 and my translation is made to favour this conjecture. 
The elder Pliny also mentions tne same fountain, and ascribes 
to it a very remarkable and unaccountable difference j for he 
asserts, that it ebbs and flows regularly in the space of an hour. 
Hist. Nat. Lib. II. Cap. ciii. We are surprised to find the 
uncle and nephew, both intelligent and observing men, vary 
so widely in the statement of an obvious fact. Their disagree- 
ment, however> does not contradict the regularity of the 
spring’s operations, which is a consideration of importance in 
the natural history of reciprocating fountains. As for the ques- 
tion of accuracy, it has been decided in the uncle’s favour by 
Catanaeus, the learned commentator on the epistles of the ne- 
phew j who says, the fountain continued to reciprocate in his 
time, that the neighbours called it Pliny’s well, and that it an- 
swered to the description given of it by the elder writer of that 
name. After all, future observations may prove both these 
authors to be in the right. Perhaps it will be found, that wet 
weather accelerates the reciprocations of the spring, by in- 
creasing its discharges 3 while a dry season diminishes the 
efflux of water, and makes the fountain more dilatory in its 
operations. The preceding conjecture is countenanced by the 
reciprocating spring at Giggleswick 5 for it ebbs and flows 
most frequently after copious rains 3 but the depth of the well 
shews the greatest variations when the efflux is but small. 
The elder Pliny also takes notice of another reciprocrating 
spring, and gives the following short character of it with his 
usual brevity. The fountain of Jupiter, in Dodona, ex- 
tinguishes lighted tapers like any other cold water 3 but if a 
taper be first extinguished, and then brought to the surface 
of the well, it takes fire again. This fountain is called 
ANAIIAYMEN02 that is, the Loiterer , because it is empty 
at noon ; but beginning to increase after mid-day, it overflows 
in the middle of the night, and then subsides again gradually.” 
Hist. Nat. lib. II. cap . ciii. 
A third extraordinary fountain of this kind is mentioned 
by various modern authors. It is said to be in Paderborn, a 
district of Westphalia, aed to go by the name of Bolder- born, or 
t he 
