94 



Mr. Ayres stated that he had made similar observations 

 to those of Mr. Cabot. 



He knew of an instance of a sand bank, eight feet high, 

 formed within his recollection, in which fresh water miglu be 

 obtained at the depth of eighteen inches. At Sag-Harbor, where 

 he had resided for some years, there is a well, about forty 

 rods from the tide, in which the waier rises and falls four 

 feet, a liitle after the tide. A little further from the shore is 

 another, which rises and falls two feet; a well still further off, 

 rises and falls one foot ; at a short distance above this is one 

 which is not sensibly affected. 



Mr. J. E. Cabot mentioned a statement of Darwin's, that 

 on the Coral Islands of the Pacific, fresh water may be easily 

 procured by digging a short distance below the surface. 



Dr. Pickering stated that he had himself seen the natives 

 of these islands obtain a supply whenever it was wanted, by 

 making a slight excavation. In reply to a question from 

 Mr. Ayres, whether the water in the lagoons of these islands 

 is always salt, he stated that so far as he had examined 

 them it is so. They either communicate directly with 

 the sea, or else are separated from it by a barrier over which 

 it easily passes in storms. In reference to the point that 

 fresh water in sand deposits does not necessarily correspond 

 in level with the neighboring salt water, he called the atten- 

 tion of the Society to the fact, that imbibition or capillary 

 attraction affords a ready means of accounting for it. In 

 Lower Peru, w^here it never rains, and the country is fertil- 

 ized by irrigation, he remarked that the soil is found to be 

 moist several feet above the surface of the water in the 

 canals. 



A gentleman present, not a member of the Society, sug- 

 gested that the difference of specific gravity of salt and 

 fresh water might be a satisfactory reason for their not inter- 

 mingling in the sand formations examined by Mr. Cabot. 



The subject under consideration suggested to the Presi- 



