Near Argostoli, on the southern coast of the island of Cephalonia, in Greece, a stream of salt water has for an unknown period of time left the almost tideless sea, and, flowing inland with a volume sufficient to furnish water power to two mills, finally disappeared in fissures representing enlarged joint cracks in the limestone. This remarkable reversal of the normal conditions of drainage and the disposal of the immense quantities of water sinking into the limestone have long been themes for speculation. I t remained for F. W. and W. O. Crosby,* however, to offer the first plausible explanation, which, in brief, is the differential action of the earth’s interior heat on an unsymmetrical passage with a short “inlet” and a long “outlet” arm, the water in the latter, because of its greater exposure to the heat, being warmer and lighter than in the short arm, thus establishing . . .