224 Contributions to Physical Geography. 



On the southern side, the bottom and bank of the lake yawn 

 into a similar set of apertures, through which, as the rains set 

 in towards the end of autumn, water begins to rise. It con- 

 tinues increasing in quantity, and gradually fills the deeper 

 hollows of the deserted bed. Even some of the openings on 

 the northern side, which had assisted to drain the lake, now 

 send forth their stores from beneath to fill it. As the rains 

 continue, the waters issue from these apertures with such im- 

 petuosity, that pike are said to have been frequently taken, 

 wounded and disfigured in a manner which could only be ex- 

 plained on the supposition, that the violence of the subterra- 

 nean streams had dashed them to and fro against the rocks of 

 the hidden passage, through which it hurries them upfrom deep- 

 er reservoirs, before they emerge into the lake. So soon as the 

 waters begin to appear, the birds which had nestled in the long 

 grass seek another refuge ; the peasant removes in haste what 

 of his hazardous crop may still remain within the margin of 

 the basin ; and within as short a time as that in which it had 

 retired, the lake is again there in all its former extent, and 

 stocked with its former inhabitants. 



The length of the time in which it remains dry, depends en- 

 tirely on the comparative dryness of the season. The waters 

 ran off in the summer of 1821, returned toward the end of No- 

 vember, and ran off a second time in the end of February 1822, 

 not, indeed, an ordinary occurrence, but perfectly natural ; be- 

 cause no rain had fallen from the beginning of January, and 

 the snow on the higher mountains still continued to be frozen. 

 Sometimes, again, when the summer is decidedly what may be 

 called a wet one, the lake does not retire at all ; all proofs that 

 the sources of its waters are not subterranean, although the 

 channels which conduct them into this basin are subterranean. 



The phenomena of this lake, therefore, do not seem either 

 to be of very difficult explanation, or to deserve the astonish- 

 ment with which many travellers, and some naturalists have re- 

 garded them. The whole ridge of mountains consists of a very 

 porous calcareous rock, through which the rains and melted 

 snow easily penetrate. It is traversed, likewise, internally by 

 innumerable suites of galleries and caverns, in which the wa- 

 ters unite themselves into streams, and pursue their subterra- 



