94 



and therefore should be able to read the gas meter which in- 

 dicates their consumption of gas. Such gas meters are fur- 

 nished by the companies, and can be read with little effort. 



The instrument itself is somewhat complex. It will suffice 

 to say that within the meter box are thin disks which are 

 moved by the stream of gas that passes them. This move- 

 ment of the disks is recorded by clockwork devices on a dial 

 face. In this way, the number of cubic feet of gas which 

 pass through the meter is automatically registered. (See 

 Laboratory Manual.) 



88. Water Pressure. A pressure gauge of somewhat dif- 

 ferent form may also be used to measure the pressure of 

 water. If the gauge is attached to a faucet and the faucet is 

 opened, the pressure of the water is indicated by the rise of 

 the mercury as in Section 86. The city or town is under 

 obligation to furnish the householder with water under a pres- 

 sure sufficient to give a strong, rapid flow, and if the supply 

 from faucets becomes feeble and slow, the pressure is below 

 its proper value. 



In summer when prolonged drought occurs, the pressure 

 falls considerably, but for this no one can be held directly 

 responsible. 



