Ebbing and Flowing Well. 377 
complete; he has not informed his friend 
Licinius, how he supposes the air gets into 
the subterranean channel, which supplies his 
well with water. Perhaps this omission was 
the effect of design, rather than of negli- 
gence ; for many philosophers in Pliny’s time 
held the singular opinion, that the earth pos- 
sesses the faculty of respiration like animals ; 
in consequence of which it inhales and expires 
air through the crannies and caverns, which 
extend to its surface. Supposing Licinius 
to be of this way of thinking, Pliny had no 
reason to tell this ingenious and learned man, 
that he imagined the outlet of the fountain 
had a communication under ground, with one 
of these spiracles of the globe. Be this as 
it may, the notion is too absurd to be mert- 
tioned in the present improved state of Na- 
tural Philosophy, in any other light than as 
a curious document of the puerile conceits 
with which the philosophers of ancient times 
amused their hearers. Ln the foregoing 
attempt to’ complete the theory, I have 
had recourse toa well known phenomenon; 
water is beaten into foam by being agitated ; 
which was the case with Mr. Swainston’s 
vessel, because a strong current fell into it 
from the pump. There is, however, one 
objection still remaining, which deserves to 
3B 
