READING THE GAS METER 



201 



water rises as it becomes lighter, and passes into the pipe of 

 the hot- water tank. When the hot water is drawn from the 

 faucet, a supply of cold water enters through the pipe which 

 enters at the top of the tank and extends down to a level just 

 above the top of the heating device. In the instantaneous 

 gas heater, the gas is automatically turned on and lighted 

 by a pilot flame when the faucet is opened. The water is 

 heated as it passes through the coiled pipes in the flame. 

 Reading the gas meter. Since gas is a commodity which 

 is delivered to our homes, we should learn to read the meters, 



CUBIC 



Recording dials of gas meter. 



so as to be able to know how much gas is burned, and 

 whether we use it economically. The recording device of 

 a small gas meter has three small dials, and a fourth one 

 still smaller on top, which has a scale registering two cubic 

 feet. Above the three dials are marked the figures 100,000, 

 10,000, and 1,000, and the face of each dial is figured from 

 o to 9. When the gas passes through the meter, the hands 

 revolve, the two outer ones in the direction of the hands of a 

 clock, and the inner one in the opposite direction. In the 

 illustration the 100,000 dial hand is between 5 and 6, the 

 10,000 between 5 and 6, and the 1,000 at 8. This means 



