ces under which, the
phenomenon first showed itself, all that can be said is, that the
earliest literary witness to the fact is Strabo (about B.C. 25); that
the earliest of the inscriptions on the base that can be dated belongs
to the reign of Nero, and that it is at least questionable whether the
sound ever issued from the stone before B.C. 27. In that year there was
an earthquake which wrought great havoc at Thebes; and it is an acute
suggestion, that it was this earthquake which at once shattered the
upper part of the colossus, and so affected the remainder of the block
of stone that it became vocal then for the first time. For centuries the
figure remained a _torso_, and it was while a _torso_ that it emitted
the musical tone--

"_Dimidio_ magicae resonabant Memnone chordae."

After a long interval of years, probably about A.D. 174, that
restoration of the monument took place which is to be seen to the
present day. Five blocks of stone, rudely shaped into a form like that
of the unharmed colossus, were emplaced upon the _torso_, which was thus
reconstructed. The intention was to do Memnon honour; but the effect was
to strike him dumb. The peculiar condition of the stone, which the
earthquake had superinduced, and which made it vocal, being changed by
the new arrangement, the sound ceased, and has been heard no more.

It is a fact well known to scientific persons at the present day, that
musical sounds are often given forth both by natural rocks and by
quarried masses of stone, in consequence of a sudden change of
temperature. Baron Humboldt, writing on the banks of the Oronooko, says:
"The granite rock on which we lay is one of those where travellers have
heard from time to time, towards sunrise, subterraneous sounds,
resembling those of the organ. The missionaries call these stones _loxas
de musica_. 'It is witchcraft,' said our young Indian pilot.... But the
existence of a phenomenon that seems to depend on a certain state of the
atmosphere cannot be denied. The shelves of rock are full of very narrow
and deep crevices. They are heated during the day to about 50 deg.. I often
found their temperature during the night at 39 deg.. It may easily be
conceived that the difference of temperature between the subterraneous
and the external air would attain its _maximum_ about sunrise."
Analogous phenomena occur among the sandstone rocks of El Nakous, in
Arabia Petraea, near Mount Maladetta in the Pyrenees, and (perha