222 M. L. FULLER — THE SEA MILLS OF CEPHALONIA 



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 the necessary conditions for circulation. 



The object of the present paper is to call attention to another possible, 

 but heretofore unrecognized, factor in the circulation, namely, the differ- 

 ence in the density in different parts of the passage due to an admixture 

 of fresh water with the salt. Both heat and dilution may unquestionably 

 be real causes of circulation of the Cephalonia type, and it only remains 

 to determine their relative effectiveness and probability. In doing this 

 we must rely on the evidence afforded by the local conditions in the 

 Cephalonia region, especially in regard to the neighboring springs, and 

 on our general knowledge of the nature of deep circulation. 



The writer wishes at this point to express his thanks to Professors 

 W. 0. Crosby and J. F. Kemp for a number of suggestions, and to 

 acknowledge his indebtedness to the paper cited for the descriptive data 

 relating to the mills. 



General Conditions 



location 



The town of Argostoli, near which the sea mills are located, is situated 

 on the southwest side of Cephalonia, an island some 20 miles in length 

 lying off the gulf of Patras, on the west coast of Greece. Speaking more 

 exactly, it is situated on the inner side of a low, narrow peninsula of 

 limestone projecting northward from the east side of the gulf of Argos- 

 toli, and forming the harbor toward which the town faces. The two sea 

 mills are at the extremity of this promontory, about a mile north of the 

 town. The first mill to be seen is that of Doctor Migliaressi, established 

 in 1859 ; the second, erected by Mr Stevens, an Englishman, in 1835, 

 is a quarter of a mile farther on and near the end of the point. The 

 mills, when in operation, took their power from undershot wheels driven 

 by a current of salt water conducted from the sea by an artificial channel. 

 They have now been abandoned, however, for some time, owing to the 

 competition of larger and better equipped mills elsewhere. 



NATURE OF THE PHENOMENA 



Originally, according to the descriptions of Professor D. T. Anstead 

 in his book on the Ionian islands (page 322), the sea at its ordinary 

 level entered the land at four points, forming a narrow creek which 



