190 



Introduction to the Study of Science 



water is brought to the city. In quantity there is more than 

 sufficient to supply the needs of two millions and more of 

 people. The water pressure in the city is so great as to render un- 

 necessary any additional force, as by pumps. This, however, is 



! . . _, , | not unusual on 



the Pacific coast 

 or in the Rocky 

 Mountain region 

 where the supply 

 comes from great 



FIG. 55. Section of con- 

 duit of the Los Angeles 

 water supply. A steel si- 

 phon crossing nine-mile can- 

 yon 850 feet deep. It rises 

 on the other side to within 

 30 feet of height on this 

 side. Insert : Diameter of 

 steel pipe is 11 feet, its 

 length 30 feet ; the steel is 

 1| inches thick. 



The New York City 

 supply. After many 



years of dependence upon the Croton watershed for its supply, 

 New York City has gone far north into the Catskill Moun- 

 tains for a source of supply that bids fair to satisfy its needs 

 for many generations to come. It has acquired control of the 



