In spite of the large growth of the city from 1908 to 1912, there has been a general decrease in the total quantity of water consumed. The decrease in total consumption is chiefly due to the metering of water to individual users, eliminating a large part of the Avater waste which formerly occurred because of carelessness on the part of consumers. The actual percentages of the services which were metered in each one of the years considered may be seen

CURVE PLOTTING

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/ie-fropoJUarr Wortsr Djsirjct Dia^i-am Shoiv/rtf Average Dcnily Consumpfion of iVarisr

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Counesy of Hazen & Whipple, New York

Fig. go. Chart Showing by Months the Average Total Daily Water Consumption in Boston, and by Months the Average DaUy •per Capita Water Consumption. Also the Yearly Average of Daily Consumption Stated in Total and per Capita

In this illustration the curves may be read from either of two different sets of co-ordinate rulings. I'sing the horizontal ruled lines, we may read from the curves the average total consumption per day. By reading from the slanting lines, the same curves may be interpreted as the average consumption per capita per day. The scheme of using two sets of co-ordinate rulings is a valuable one. The scale for "million gallons per day" should, however, have been shown only at the left, with the slanting line scale for "gallons per capita" placed in the right-hand margin for the sake of clearness