136 Regulating Valve for a Gas Estahlishmmt. 



inch main pipe leading from these works last summer, and 

 which I had the pleasure of showing to you when you were in 

 Bath in January last. 



" The valve consists of a circular plate of metal, nine inches 

 in diameter, sliding over the mouth of the main pipe, in a 

 chamber. The face of the index is a representation of the valve 

 itself; so made in order that the superintendent may know the 

 precise position of the valve at any time. 



'* The black disc A is a thin plate of metal attached to a rod 

 coming up from the valve behind the index frame, in which 

 there is a slit for the pin which carries the index to pass. \ The 

 portion of the circle B, which is uncovered by the disc, repre- 

 sents the aperture, or gas-way into the main pipe. D is a 

 pressure gauge connected with the main on the gasometer side 



