SUBTERRANEAN WATERS. A471 
soil, some is taken up by organic growths and by inorganic 
compounds, some poured out upon the surface by springs and 
either immediately evaporated or carried down to larger 
streams and to the sea, some flows by subterranean courses 
into the bed of fresh-water rivers* or of the ocean, and some 
remains, though even here not in forever motionless repose, to 
fill deep cayities and underground channels. In every case 
not appear. Other mills of the same sort have been erected, and there ap- 
pear to be several points on the coast where the sea flows into the land. 
Various hypotheses have been suggested to explain this phenomenon, some 
of which assume that the water descends toa great depth beneath the crust 
of the earth; but the supposition of a difference of level in the surface of the 
sea on the opposite sides of the island, which seéms confirmed by other cir- 
cumstances, is the most obvious method of explaining these singular facts. 
If we suppose the level of the water on one side of the island to be raised by 
the action of currents three or four feet higher than on the other, the exist- 
ence of cayities and channels in the rock would easily account for a subter- 
ranean current beneath the island, and the apertures of escape might be so 
deep or so small as to elude observation. See Aus der Natur, vol. xix., pp. 
129 e¢ seqg. I have lately been informed by a resident of the Jonian Islands, 
who is familiar with the locality, that the sea flows uninterruptedly into the 
sub-insular cavities, at all stages of the tide. 
* “ The affluents received by the Seine below Rouen are so inconsiderable, 
that the augmentation of the volume of that river must be ascribed principally 
to springs rising in its bed. Thisis a point of which engineers now take notice, 
and M. Belgrand, the able officer charged with the improvement of the navi- 
gation of the Seine between Paris and Rouen, has devoted much attention to 
it.”—BaBmnet, Htudes et Lectures, iii., p. 185. 
On page 232 of the volume just quoted, tne same author observes: ‘‘ In 
the lower part of its course, from the falls of the Oise, the Seine receives so 
few important aflluents, that evaporation alone would suffice to exhaust all 
the water which passes under the bridges of Paris.” 
This supposes a much greater amount of evaporation than has been usually 
computed, but I believe it is well settled that the Seine conveys to the sea 
much more water than is discharged into it by all its superficial branches. 
Babinet states the evaporation from the surface of water at Paris to be twice 
as great as the precipitation. 
Belgrand supposes that the floods of the Seine at Paris are not produced by 
the superficial flow of the water of precipitation into its channel, but from 
the angmented discharge of its remote mountain sources, when swollen by 
the rains and melted snows which percolate through the permeable strata in 
its upper course. —Annales des Ponts et Chaussées, 1851, vol. i. 
