78 TKANSACTIONS OF THE [jAN. 31, 



adopted and the large and constant volume of water obtained 

 were alluded to as constituting a new and successful experiment 

 on a large scale in connection with the supply of water to 

 towns. 



Since the publication of the paper referred to, the Messrs. 

 Andrews & Co., contractors, have established two additional 

 *' plants " along the line of the Brooklyn Aqueduct, increasing 

 the supply for the city to eighteen millions of gallons daily 

 from this source alone — a quantity equal to one-sixth of the 

 supply to the city of New York at the present time. 



This large volume of water is obtained from four hundred 

 and sixty (460) 2-inch tubes (equivalent in area of cross section 

 to a single tube or pipe 44 inches diameter) driven from forty 

 to seventy feet into the gravel deposits. On a trial-test, these 

 tubes have furnished twenty-seven millions of gallons in twenty- 

 four hours. Eighteen millions is not, therefore, the maximum 

 supplying capacity of these wells at this time. 



It is not contended that there is anything novel in the idea of 

 obtaining water for any purpose from the unconsolidated or 

 loose detritus of the earth's surface ; but the means and ap- 

 pliances by which such large quantities are drawn continuously 

 and permanently from a few tubes driven into the ground are 

 so effective and simple, and so much has been done to encourage 

 further operations of the same kind, and to throw light upom 

 the characteristics of these underground water-bearing deposits^ 

 that it may be said that new resources, in connection with the 

 water supply of the largest towns, have been opened to the 

 engineer — resources not always available, it is true, but in many 

 cases highly practicable and economical. 



The engineer who seeks a source from which may be obtained 

 a proper supjoly of water for a town, must take into considera- 

 tion a great variety of circumstances. Among these, the me- 

 teorological and geological conditions which prevail in the dis- 

 trict are most important, since these influence the quantity as 

 well as the quality of the water obtained. Of all the meteoro- 

 logical agencies, there are none which have more controlling 

 influence on the physical geography of the globe and the 

 adaptation of any part of its surface to the necessities of the 



