274 



THE WORLD'S ADVANCE 



points in the line, so that a continuous 

 record of the actual flow will be available. 



These meters are on a colossal scale; 

 in fact, they are the largest meters ever 

 built. At the upstream castings the di- 

 ameter of the waterway is 17 feet 6 

 inches, and at the throat of the meter the 

 diameter is 7 feet 9 inches. Each meter 

 is based upon the principle of the con- 

 servation of energy, and each consists of 

 a contracted section, or throat, the func- 

 tion of which is to introduce an artificial 

 depression. 



The interior contour is 

 shown in the diagram, and 

 the accuracy of the meter 

 greatly depends upon its 

 proper design. As the water 

 flows from A toward the 

 throat, B, its velocity rapid- 

 ly increases, and the pressure 

 at B becomes materially less 

 than the pressure at A. The 

 difference in pressure be- 



In order to fix the location of these 

 huge measuring devices it may be ad- 

 vantageous to review briefly the principal 

 parts of the Catskill system. The water 

 will be collected in the Ashokan reser- 

 voir, 100 miles north of New York, and 

 will flow south by gravity through the 

 aqueduct to the Kensico storage reser- 

 voir, about 30 miles from the city. From 

 the Kensico reservoir the water will be 

 delivered into an equalizing basin at Hill 

 View, and from this point the flow will 



tween A and B can be accurately meas- 

 ured, and bears an exact ratio at all times 

 to the flow through the throat B. 



After passing the throat the velocity 

 begins to decrease with an accompanying 

 rise in pressure, and when C is reached 

 the pressure temporarily lost at B has 

 been almost entirely regained. There- 

 fore, a properly proportioned tube not 

 only provides a basis for accurate meas- 

 urement of the flow, but it delivers prac- 

 tically the same amount of water as a 

 straight pipe of equal length and di- 

 ameter. 



Above: Forms and Reinforcement 

 Rods in Place, Prior to Pouring 

 the Concrete for One of the Meter 

 Tubes. At the Left: Looking 

 Through the Throat Section of the 

 Largest Water Meter in the 

 World. 



be carried to points of connection with 

 the city's distribution system by means 

 of a deep pressure tunnel in rock, driven 

 the entire length of Manhattan Island. 

 The first of the three large meters is lo- 

 cated at the outlet of the Ashokan reser- 

 voir; the second is at the inlet to the 

 Kensico reservoir; and the third is at 

 the outlet from the Kensico reservoir. 



All the meters are built in the aqueduct 

 line and will carry the full flow. There 

 are several reasons for using three me- 

 ters instead of one. On a conduit the 

 length of the Catskill Aqueduct there is 



