PIPES I^OR IRRIGATION PURPOSES. II 7 



trenches for this system should be dug two feet deep 

 and sixteen inches wide, and the pipe itself is laid by 

 a patented machine shown in Fig. 25, which also 

 illustrates the manner of laying. 



The material used is Portland cement, dry-slaked 

 lime free from lumps, and perfectly clean sand. The 

 proportion is seven parts sand, one part cement, and 

 one part lime. One barrel of cement and one of lime 

 with a proportionate amount of sand will make 350 

 feet of two-inch pipe. The stuff is mixed as the work 

 progresses and is put into the hopper of the machine 



FIG. 26 — SIDE VIEW OF STAVE PIPE. 



by the shovelful. The operator works the lever for- 

 ward and back, and as he does so the whole machine 

 moves along a notch at a time, and leaves the com- 

 pleted string of pipe in its wake. 



Wooden Stave Pipes. — For low pressures and 

 large diameters wooden stave pipe is to be recom- 

 mended. It supplies a long- felt want between the 

 grade pipes such as vitrified clay and cement, and the 

 pressure pipes such as riveted steel or wrought iron. 

 Sedlional views are given in Figs. 26 and 27. 



