88 IRRIGATION FARMING. 



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 pro- 

 gresses and is put into the hopper of the machine by the 

 shovelful. The operator works the lever forward and 

 back, and rs he does so the whole machine moves along 

 a notch at a time and leaves the completed string of 

 pipe in its wake. 



Wooden Stave Pipes. For low pressures and 

 large diameters wooden stave pipe is to be recommended. 

 It supplies a long-felt want between the grade pipes such 



FIG. 25. SIDE VIEW OF STAVE PIPE. 



as vitrified clay and cement, and the pressure pipes such 

 as riveted steel or wrought iron. Sectional views are 

 given in Figures 25 and 2G. 



The walls of the pipe are formed of longitudinal 

 staves braced together with iron or steel bands. These 

 are shaped to cylindrical forms and on the edges to true 

 radial lines, so that when put together they form a per- 

 fectly cylindrical pipe. The flat edges of the staves are 

 essential to enable the empty pipe to resist the pressure 

 from the overlying earth. To join the ends of the staves 

 a thin metallic tongue is inserted, which being a trifle 



