Mat 17, 1907] 



SCIENCE 



767 



The Limestone Ocean of pre-Cambrian 

 Time: Reginald A. Daly. Eead by- 

 title. 



Controlling Factors of Artesian Flow: M. 



L. FtTLLEE. 



The rapid extension of well-drilling in 

 granites, schists, slates, etc., in the last few 

 years, and the obtaining in them of true 

 artesian flows at many points, together with 

 the increasing development of wells from 

 uniform xmconfined horizontal sands, has 

 made a revision of the commonly accepted 

 'requisites' of flowing wells desirable. The 

 paper discusses the character of the reser- 

 voirs, the sources of water, the confining 

 agents, and the source of pressure, and 

 concludes that the requisites of artesian 

 flows are only three in number: (1) an 

 adequate source of water supply; (2) a 

 retaining agent offering more resistance to 

 the passage of water than the weU or other 

 outlet, and (3) an adequate source of pres- 

 sure. The specific sources of water and 

 head, and the specific character of con- 

 fining agents are too variable to warrant 

 inclusion in standard requisites. 



Conditions of Circulation at the Sea Mills 

 of Cephalonia: M. L. Fuller. 

 Near Argostoli, on the southern coast of 

 the island of Cephalonia, in Greece, a num- 

 ber of streams have, for an unknown period 

 of time, left the sea and, flowing inland 

 with a volume sufficient to operate two sea 

 mills, finally disappeared in a fissured lime- 

 stone. To account for the continuous cir- 

 culation under conditions which preclude 

 any lower outlet, the action of interior heat 

 on an unsymmetrical passage with a short 

 'inlet' and a long 'outlet' arm was postu- 

 lated by F. W. and W. 0. Crosby. In the 

 longer arm, because of its greater exposure 

 to heat, the water is supposed to be warmer 

 and lighter than in the short arm, thus 

 establishing the necessary conditions for 



circulation. A difference of 20 degrees in 

 the average temperature, which may be 

 supposed to occur with a system reaching a 

 depth of 2,000 feet, would give an excess 

 of height amounting to 10.6 feet to the 

 warmer over the colder arm. The writer 

 believes a difference of density [(independ- 

 ent of temperature) in the water of the 

 two arms affords a simpler and more effect- 

 ive explanation of the circulation. If the 

 water remained unchanged in composition 

 it would rise in the outlet arm of the pas- 

 sage only to the level of its entrance; but 

 if it became diluted by an admixture of 

 fresh water, the column in the outlet would 

 be higher than in the inlet arm, and the 

 essentials for circulation would be estab- 

 lished. The specific gravity of Mediter- 

 ranean waters is 1.03, hence a column of 

 the sea water 100 feet in length will sup- 

 port a column of fresh water 103 feet high, 

 or of sea water diluted one half by fresh 

 water, a column 101^ feet in height. A 

 depth of 2,000 feet with 50 per cent, dilu- 

 tion would furnish a working head of thirty 

 feet as compared with ten feet under the 

 heat hypothesis, while a head of three 

 fourths of a foot, or enough to establish 

 circulation, would be produced under the 

 same dilution at a depth of fifty feet, or 

 entirely within the zone controlled by at- 

 mospheric temperatures. 



Mr. Fuller's two papers were discussed 

 by Professors Kemp and Davis. 



Normal Pressure Faulting in the Allegheny 

 Plateaus: George H. Ashley. Read by 

 title. 



Geological Structure of the Uinta Moun- 

 tains: S. F. Emmons. 

 The Uinta Mountains form a range 

 vmique in the Cordilleran system, in that 

 its axis of uplift has an east-west direction, 

 and that it has a typical anticlinal struc- 

 ture. The conditions under which the 



