200 



THE WORK OF RUNNING WATER 



sanitation, although for many years London and Paris 

 obtained a considerable part of their water supply from these 

 sources. 



Most of the great cities of the world are largely if not 

 wholly dependent on near-by rivers and lakes for the water 



they use. Others have 

 gone to the head- 

 waters of streams in 

 the hills or mountains, 

 have conserved these 

 uncontaminated 

 waters in huge reser- 

 voirs, and have con- 

 structed great pipe 

 lines to conduct the 

 water to the cities' 

 mains. The Los An- 



1 ^^^_ imfc _ ^^^^_ geles aqueduct brings 

 Ifelfitofe water for a distance 



of 250 miles down 

 over the foothills and 

 through the desert. 

 It is capable of sup- 

 plying a population of 

 2,000,000. Such an 

 engineering feat makes 

 the ancient aqueducts look almost insignificant. 



How Water is Delivered through Cities. Ancient cities 

 had not the advantages of modern pressure pumps. They 

 were, therefore, dependent upon gravity to bring water to 

 them from sources higher than the community served. 

 Whenever possible, modern cities obtain their water sup- 



A PRIMITIVE WATER CARRIER IN MEXICO 



