THE WATER-METER.
Some consumers pay a sum quarterly for the privilege of a water supply, and the water company allows them to use as much as they require. Others, however, prefer to pay a fixed amount for every thousand gallons used. In such cases, a water-meter is required to record the consumption. We append a sectional diagram of Kennedy's patent water-meter (Fig. 183), very widely used. At the bottom is the measuring cylinder, fitted with a piston, (6), which is made to move perfectly water-tight and free from friction by means of a cylindrical ring of india-rubber, rolling between the body of the piston and the internal surface of the cylinder. The piston rod (25), after passing through a stuffing-box in the cylinder cover, is attached to a rack, (15), which gears with a cog, (13), fixed on a shaft. As the piston moves up and down, this cog is turned first in one direction, then in the other. To this shaft is connected the index mechanism (to the right). The cock-key (24) is so constructed that it can put either end of the measuring cylinder in communication with the supply or