SERVICES. 189 



which consists of a short piece of tubing with a stop-cock near its extremity. Hither 

 the condensable products will flow, and may be drawn off periodically. 



****** 



" Where it can be done without inconvenience, it is a good plan to turn off the main- 

 cock at night, thereby excluding gas from the premises." 



****** 



Mr. Parker's work is full of useful instruction, and I cannot do better than 

 refer my readers to it for further information on the subject of fittings and 

 consumers' meters. 



