470 SUBTERRANEAN WATERS. 
apertures.* Some of this humidity is exhaled again by the 
* The great limestone plateau of the Karst in Carniola is completely honey- 
combed by caves through which the drainage of that region is conducted. 
Rivers of considerable volume pour into some of these caves and can be traced 
underground to their exit. Thus the Recca has been satisfactorily identified 
with a stream flowing through the cave of Trebich, and with the Timayo— 
the Timavus of Virgil and the ancient geographers—which empties through 
several mouths into the Adriatic between Trieste and Aquileia. The city of 
Trieste is very insufficiently supplied with fresh water. It has been thought 
practicable to supply this want by tunnelling through the wall of the plateau, 
which rises abruptly in the rear of the town, until some subterranean stream 
is encountered, the current of which can be conducted to the city. More 
visionary projectors have gone further, and imagined that advantage might be 
taken of the natural tunnels under the Karst for the passage of roads, rail- 
ways, and even navigable canals. But however chimerical these latter schemes 
may seem, there is every reason to believe that art might avail itself of these 
galleries for improving the imperfect drainage of the champaign country 
bounded by the Karst, and that stopping or opening the natural channels 
might very much modify the hydrography of an extensive region. See in 
Aus der Natur, xx., pp. 250-254, 263-266, two interesting articles founded on 
the researches of Schmidt. 
The cases are certainly not numerous where marine currents are known to 
pour continuously into cavities beneath the surface of the earth, but there is 
at least one well-authenticated instance of this sort—that of the mill-streams 
at Argostoli in the island of Cephalonia. It had been long observed that the 
sea-water flowed into several rifts and cavities in the limestone rocks of the 
coast, but the phenomenon has excited little attention until very recently. In 
1833, three of the entrances were closed, and a regular channel, sixteen feet 
long and three feet wide, with a fall of three feet, was cut into the mouth of 
a larger cavity. The sea-water flowed into this canal, and could be followed 
eighteen or twenty feet beyond its inner terminus, when it disappeared in 
holes and clefts in the rock. 
In 1858 the canal had been enlarged to the width of five feet and a half, 
and a depth of a foot. The water pours rapidly through the canal into an 
irregular depression and forms a pool, the surface of which is three or four 
feet below the adjacent soil, and about two and a half or three feet below the 
level of the sea. From this pool it escapes through several holes and clefts 
in the rock, and has not yet been found to emerge elsewhere. 
There is a tide at Argostoli of about six inches in still weather, but it is 
considerably higher with asouth wind. I do not find it stated whether water 
flows through the canal into the cavity at low tide, but it distinctly appears 
that there is no refluent current, as of course there could not be from a basin 
so much below the sea. Mousson found the delivery through the canal to be 
at the rate of 24.88 cubic feet to the second; at what stage of the tide does 
