STREET-MAINS. 161 



Joints. 



To make the joints, spun yarn is driven between the pipes to within 2^ 

 inches of the lip of the socket, and a good fitting of the two pipes being 

 effected, melted lead is poured into the remaining cavity, which, when set, 

 is caulked or hammered in with a blunt square- pointed chisel. There is no 

 necessity for driving the lead in'very hard, as the joint will not be at all the 

 tighter in consequence ; it is very probable that the ordinary sockets before 

 alluded to were split by downright hard- wedging ; no metal will stand against 

 such force. A strict watch must be kept over the men while jointing ; they 

 are very apt to stint the quantity of lead if the work be done by contract. 



After a certain length of main-pipe has been laid, it ought to be proved, in 

 order to be certain that all the junctures are gas-tight. The most convenient 

 manner of doing this is by means of a portable gas-holder (from two feet six 

 inches to three feet diameter, running upon a truck) filled with common air, 

 and connected, by means of a small service, with the length of mains to be 

 tried. This gasometer should be made to act with a pressure at least four 

 times greater than the pressure of gas they will afterwards have to sustain. If 

 the mains are tight, the vessel will remain stationary ; if not, it will descend 

 in proportion to the extent of the leak. 



This is very seldom done, because it is attended with a little additional ex- 

 pense and trouble ; but if an engineer wishes to increase the oaconomy of his 

 establishment, he will do well to insist upon every quarter of a mile being 

 proved whilst the mains are in progress of laying. From the careless manner 

 in which the mains are generally laid, more gas is lost than all the oeconomy 

 in the works can make up. 



The prices commonly given to the foreman pipe-layer for laying mains of 

 the following sizes, by contract, are, 



For 2- and 3-inch mains 4d. per yard. 

 4-inch ditto - - 4A 



I 



5 -inch ditto - 

 6-inch ditto 

 8-inch ditto - 



For 10-inch mains - 1 per yard. 

 12-inch ditto 1 1 



14-inch ditto -12,, 



18-inch ditto - 1 8 



The foreman will find his own picks and small tools, watchings, coals and 

 candles. The Company is at the expense of repair of lead pipes and roads, 

 carting the mains to the spot, and removing rubbish. The above prices are 



Y 



