THE MANAGER IN THE DISTRICT. 97 



be consulted. On page 195 will be found a table of this 

 kind calculated for a loss of 4-tenths pressure. It was 

 drawn up over thirty years ago for use with flat-flame 

 burners, and in applying it in connection with incandes- 

 cent or atmospheric burners, there are many positions, such 

 as the far end of the district, or a low-level position, where 

 even a loss of 4-tenths may be objectionable. The table 

 allows no margin for such contingencies as accumulation 

 of rust in the pipe or for the obstructive effect of bends 

 or curves. The meter, in the course of years, works 

 stiffer, and absorbs more pressure than when it was new. 

 There must be no sailing close to the wind in the matter 

 of the size of the service pipe; and there is no reason 

 for niggardliness in regard to this mrtter, because the 

 difference in cost as between one size of pipe and the 

 next larger is a mere trifle. If, in the above example, 

 the service is 36 feet long, the table shows that a J-mch 

 pipe would supply 180 cubic feet per hour. But no 

 competent filter would think of laying less than i-inch 

 pipe. To get a satisfactory result, it is well to take about 

 twice the maximum consumption shown in the table. 

 If 200 cubic feet is required, lo^k out the size and length 

 of pipe for 400 cubic feet. 



The table is also useful for calculating the size of pipe 

 required for a gas engine, a cooker, or any other appliance. 



Sharp bends and elbows should always be avoided when 

 practicable. A right-angle turn has a very appreciable 

 effect as regards delivering capacity, and it also offers 

 facility for accumulations of rust. A straight run of pipe 

 can be satisfactorily cleared with a force pump, but if there 

 are two or more elbows, the result is different. The force 

 of the pump drives the rust into the corners, and to make 

 a good job the pipe must be taken apart. An elbow at 



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