eeroo
cradoo_, or) the "crying shell," a name in which the sound seems to have
been adopted as an echo to the sense. I sent them in search of the
shell, and they returned bringing me some living specimens of different
shells, chiefly _littorina_ and _cerithium._[1]

[Illustration: CERITHIUM PALUSTRE.]

[Footnote 1: _Littorina laevis. Cerithium palustre._ Of the latter the
specimens brought to me were dwarfed and solid, exhibiting in this
particular the usual peculiarities that distinguish (1) shells
inhabiting a rocky locality from (2) their congeners in a sandy bottom.
Their longitudinal development was less, with greater breadth, and
increased strength and weight.]

In the evening when the moon rose, I took a boat and accompanied the
fishermen to the spot. We rowed about two hundred yards north-east of
the jetty by the fort gate; there was not a breath of wind, nor a ripple
except those caused by the dip of our oars. On coming to the point
mentioned, I distinctly heard the sounds in question. They came up from
the water like the gentle thrills of a musical chord, or the faint
vibrations of a wine-glass when its rim is rubbed by a moistened finger.
It was not one sustained note, but a multitude of tiny, sounds, each
clear and distinct in itself; the sweetest treble mingling with the
lowest bass. On applying the ear to the woodwork of the boat, the
vibration was greatly increased in volume. The sounds varied
considerably at different points, as we moved across the lake, as if the
number of the animals from which they proceeded was greatest in
particular spots; and occasionally we rowed out of hearing of them
altogether, until on returning to the original locality the sounds were
at once renewed.

This fact seems to indicate that the causes of the sounds, whatever they
may be, are stationary at several points; and this agrees with the
statement of the natives, that they are produced by mollusca, and not by
fish. They came evidently and sensibly from the depth of the lake, and
there was nothing in the surrounding circumstances to support the
conjecture that they could be the reverberation of noises made by
insects on the shore conveyed along the surface of the water; for they
were loudest and most distinct at points where the nature of the land,
and the intervention of the fort and its buildings, forbade the
possibility of this kind of conduction.

Sounds somewhat similar are heard under water at some places on the