intervals as long as the apparatus is kept in service. Before me lies a bill giving the 'present state' as 1,700 and the 'previous state' as 96,300. Since the meter was continuously employed, it must have registered up to 100,000, so that it registered 3,700 cubic feet on the old score before recording 1,700 cubic feet on the new. Consequently, adding 1,700 to the difference between 'previous state' and the highest possible reading gives 5,400 cubic feet—the amount consumed during
Fig. 4.-Interior of Common Gas Meter.
the month. By reading one's own meter the detection of any error on the part of the indexer or of the clerical force at the gas office becomes possible. Errors of this nature are of rare occurrence, as those who have adopted this plan of checking gas bills will testify. The responsibility for excessive bills is thus taken from the gas employees and thrown entirely upon the gas-registering mechanism itself. Those people, then, who chuckle furtively over the fact that the gas company has not
