DISTRIBUTION. 55 



length of pipe required to be ordered, or for setting out 

 distances in contracts for excavating or pipe-laying. The 

 details given on them afford a great deal of useful informa. 

 tion. From the contour lines and bench marks, a sufficient 

 idea of the levels all over the district can be obtained to 

 enable the positions for drip boxes to be located. One can 

 also locate the principal thoroughfares and the class of 

 property throughout the district. 



The skill and care exercised in setting out the mains will 

 have a decided and permanent effect on the item of un- 

 accounted-for gas. But that is not all. The pipes should 

 also be laid by experienced men who have some knowledge 

 of the conditions necessary to ensure a proper supply. I 

 was once consulted about difficulties that had arisen in 

 respect to a run of main of about three miles, which I was 

 assured was laid by a thoroughly competent and experienced 

 man. But further inquiry showed that his experience had 

 been confined to water pipes, and that he did not under- 

 stand the object of providing drip boxes, and had not used 

 a level or taken any means to secure a proper " run " for 

 the pipes. 



The usual plan is to lead off from the works with a 

 single line of pipe, and to gradually reduce the size 

 towards the far end of the district. But this is not always 

 conducive to a sufficient but not excessive pressure in all 

 parts, which is the object of efficient distribution. If the 

 works is at one end of, or outside the district, the desir- 

 ability of carrying a trunk or feeding main to a central 

 position should be considered. The same applies to any 

 part of the district that may present special features as to 

 altitude, as being substantially above or below the remainder, 

 or to a specially large consumer, such as a factory that 

 works night shifts. It is not good management to keep 



