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Page:Popular Science Monthly Volume 90.djvu/917

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Popular Science Monthly

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��Pittsburgh on a smoky day. The Mellon Institute investigations showed that smoke had a depressing effect upon the minds of many people. It also had a marked effect on health

��the annual deposit during 1910-11 was 820 tons per square mile.

In Great Britain the recently formed Committee for the Investigation of Atmos- pheric Pollution has installed standard measuring apparatus in sixteen English and Scotch towns. In some cases there are as many as ten stations in a single town. The organization is analogous to a meteorologi- cal service, with its network of stations for observing the weather. The standard collector, or "pollution gage," consists of a large cast-iron funnel, enameled on the

��inside, having a collecting area of four square feet. Projecting above the gage is a wire screen, open at the top, intended to prevent birds from settling on the edge of the vessel. The gage communicates at the bottom by a tube with one or more bottles for collecting rain-water, with its solid contents. The bottles are emptied once a month and their contents analyzed. Thus information is obtained not only as to the total monthly deposit of soot and dust, but as to its chemical composition. The intens- ity of sunlight is also measured.

���The same view as above, photograpiu<i wncn Pittsburgh was rid of the smoke evil. The city now saves more than a million dollars annually on its lighting, laundiy, and cleaning bills

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