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Popular Science Monthly 



Bathing under the glare of the calcium has become a popular recreation at some of Chicago's 

 extensive beaches on the shores of Lake Michigan 



Swimming by Searchlight 



FOR the benefit of the tired business 

 man and the tired business woman, 

 unable to take advantage of Chicago's 

 twenty-two miles of lake front during 

 the daytime, the city has installed along 

 some of the beaches powerful electric 

 searchlights, so that the bathers can see . 

 just where, and with whom, they are 

 swimming. After nightfall, the lights 

 are turned on, throwing their rays in 

 various directions, so that the bathers 

 have plenty of illumination both 

 on the beach and at a generous 

 distance into the lake. 



Aside from giving the 

 Chicagoans a new form of 

 water sport, it makes 

 their swimming per- 

 fectly safe. 



A Strange Persian 

 Cistern 



PERHAPS 

 nothing 

 could better 

 illustrate the 

 difficult 

 nature of 

 Persia as 

 regards 

 military op- 



Water is carried many miles through conduits and de- 

 posited in these remarkable dome-covered Persian cisterns 



erations than the accompanying photo- 

 graph which shows the extreme measures 

 that have to be adopted for the conserva- 

 tion of water over a large part of the 

 region in which the Turks, Russians, 

 and even a considerable number of 

 Persians are now in conflict. 



The Caspian watershed of Persia is 

 fairly well watered and wooded, but all 

 the region south of about the latitude 

 of Teheran — the central and southern 

 zones — are almost absolute desert, the 

 largest cities being near the base of 

 the mountains where the rivers 

 have not had time to be absorb- 

 ed in the burning sands. At 

 other points there are oc- 

 casional wells and springs, 

 but the principal sources 

 of water in these 

 desert regions are the 

 strange cisterns such 

 as shown in the 

 illustration. 

 Stone con- 

 duits carry 

 water from 

 the moun- 

 tains to the 

 cisterns on 

 the desert 

 plains. 



