Page:Popular Science Monthly Volume 88.djvu/848

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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.

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