December 21, 1905] 



NA TURE 



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HYDROLOGY IN THE UNITED STATES. 

 \A7E have referred on previous occasions to the very 

 complete way in which hydrological research is 

 carried out in the United States, and to the value of the 

 reports that are made from time to time by the officers 

 having charge of the works. 1 We have been favoured with 

 twenty-five further reports recently issued. The greater 

 part of these refer to the water resources, and to the 

 surveys being carried out by the departments in the different 

 States. These are principally of local interest, although 

 they contain a great deal of information useful to 

 those engaged in water supply. Some of these reports, 

 however, relate to matters that are of more general 

 interest. 2 



Paper ng contains an index to the hvdrographic pro- 

 gress reports, 18S8-1903, and paper 120 a review and 

 index to papers relating to underground waters published 

 bv the United States Geological Survey, 1879-1904. 



Report No. no, on the hydrology of the eastern United 

 States, contains twenty-three short papers by nineteen 

 geologists and physicists connected with the eastern section 



of this division of 

 hydrology. The 



most interesting of 

 these papers is that 

 which relates to the 

 methods used in 

 measuring the velo- 

 city, direction, and 

 quality of under- 

 ground water. 



The Discharge of 

 Sewage into Porous 

 Strata. — In one of 

 the papers, bv 

 S. W. Callie, is 

 recorded the experi- 

 ments made t o 

 ascertain what 

 would be the effect 

 of discharging town 

 sewage into pervious 

 strata on the water 

 supply of the neigh- 

 bourhood drawn 

 from wells. 



The town of 

 Quitman derives its 

 water supply from a 

 well in the lime- 

 stone at a depth of 

 123 feet from the 

 surface. A section 

 of the soil shows 



■2 feet of surface 

 sand, 60 feet of 

 clay, 15 feet of 

 Fig. 1.— Electrode and p-rforated brass sand, and 43 feet 



buckets used in charging wells. Q f water-bearing 



limestone. 

 The authorities of the town were seriously considering 

 the question of disposing of the town's sewage by means 

 of deep wells into the porous strata. The writer of the 

 paper was engaged to report as to what effect this would 

 have on the water supply. For this purpose he adopted 

 the chlorine process. Seven wells in the locality were 

 selected for making the experiment, the water in which 

 was found to stand at a lower level than that in which 

 the chlorine was to be introduced. Samples were taken 

 from these wells, and the normal amount of chlorine 

 determined. Two tons of salt were then put into the 

 test well in the form of solution during a period of five 

 days. Special precautions were taken in the method of 

 introducing the salt to ensure complete saturation of the 

 water. The normal chlorine at the well from which the 



1 "Water Supply and Irrigation in the United States" (Naturf, 

 January 7, 1904); "Relation of Rainfall to Run Off" (July 28, 1904); 

 " Floods in the Mississippi Valley " (November 3, 1904) ; " Hydrology in 

 th- United States " (December 22, 1904). 



- " Water Supply and Irrigation Papers," Nos. 99 to 132. (Washington : 

 Government Printing Office, 1904-5.) 



W 



water supply for the town was drawn was 5-44 parts in 

 a million. Four hours after the introduction of the salt 

 in the test well the chlorine began to increase, reaching 

 a maximum of 6.8o parts in twelve hours, and continued 

 during the five days, after which it 



to show 



i. 2. — Diagram illustrating electrical method of determining the velocity 

 of flow of ground water. The ground water is supposed to be moving 

 in the direction of the arrow. The up-stream well is charged with an 

 electrolyte. The gradual motion of the ground water toward the lower 

 well and its final arrival at that well are registered by the ammeter a. 

 b is the battery, and c a commutator clock which is used if a is a 

 recording : 



gradually subsided to its normal quantity. At two of the 

 other wells a similar excess of chlorine was found, but 

 at the other wells no change in the character of the water 

 took place. 



The general conclusion arrived at was that if sewage 

 were discharged into the water-bearing strata it would 

 contaminate all the wells in the locality 

 that had a depth of 120 feet or more, and ^ 



that if the proposed scheme of the munici- 

 pality had been carried out it would prob- 

 ably have resulted in a serious epidemic. 



Measurement of Underground Currents. 

 — A paper by Charles S. Slichter gives a 

 description of the underflow meter used in 

 measuring the velocity and direction of 

 underground water. 



For the purpose of measuring the under- 

 ground flow in any locality test wells are 

 sunk consisting of t|-inch or 2-inch tubes. 

 These pipes are in lengths of 6 feet or 

 7 feet, with long threads and heavy 

 wrought nipples. The well points are 

 4-feet brass jacket points of wire gauze. 

 The tubes are driven with a ram weigh- 

 ing from 150 lb. to 250 lb., the movement 

 of the tube being aided by a water jet. 

 Four wells were driven from 4 feet to 

 6 feet apart in a triangular form, one at 

 the apex and the other three at the base 

 of the triangle. The deeper the wells the 

 greater the distance apart at which they 

 were placed. 



The up-stream well is charged with a 

 strong electrolyte such as sal ammoniac, 

 which passes down stream with the under- 

 ground water to the lower wells (Fig. 1). Fig. 3.— Perforat 

 Each of the down-stream wells contains 

 within the well point an electrode consist- 

 ing of a nickel brass rod |-inch thick 

 by 4 feet long, insulated from the casing by wooden spools. 

 This electrode communicates with the surface by means of 

 rubber-covered copper wire, and connects with a recording 

 ammeter. As the electrolyte reaches one of the down- 

 stream wells its appearance is at once recorded by the 



for slitting well 

 pipes. 



NO. l886, N OL. 73] 



