GAS-METER. 



129 



Motion is communicated to the train of wheel-work behind the index from 

 a spiral worm w fixed on to the axis of the drum, working into a wheel, the 

 spindle of which passes through the tube t, sealed by dipping under the water 

 contained in the case. 



The following are the principal dimensions of consumer's-meters : 



The inlet-hoods are those under the convex cover, or the inlet openings for 

 the gas, and the dimensions given are extreme depths at the circumference of 

 the drum. The outlet hoods are for the escape of the gas into the meter-case. 

 Dimensions given for the same part. 



In setting out the wrap of the hoods over the division-plates, care must be 

 taken to have them of the proper length, which will be, when the water is just 

 touching the outer end of the inlet-hood, the outlet-hood of that division 

 must be clearing the water. If the hoods are too long it will prevent the gas 

 from escaping from that division which is entering the water ; and if the 

 hoods are too short in the wrap, the gas will blow through, and the meter 

 stand still. 



The following are the London prices for meters : 



Consumer' s-Meters. 

 3 lights 



5 



10 



20 



30 



50 



100 



