PIPES FOR IRRIGATION PURPOSES. 87 



and doing the necessary earth work, with the addition of 

 replacing worn-out pipes in the case of the latter. The 

 cement pipes being softer und more porous than the vit- 

 rified are more subject to these troubles, and consequently 

 their cost of maintenance is much greater. An average 

 cement pipe will lust not to exceed eight years, but the 

 vitrified kind will last a lifetime and is certainly much 

 cheaper in the end. 



The Asbestine System. This is a method of 

 piping devised by a California man named E. M. Hamil- 

 ton, and is used exclusively in sub-irrigation. It con- 

 sists of a continuous pipe made of a combination of Port- 

 land cement, lime, sand and gravel, laid at a depth of 

 two feet or so below 

 the surface of the 

 ground, parallel to 

 the rows of trees or 

 vines in an orchard 

 or vineyard. In 

 these pipes on the 

 upper side is insert- 

 ed a nipple opposite FIG - 24 - ASBESTINE PIPE MACHINE. 

 each tree or vine, one-eighth of an inch or so in diam- 

 eter, through which the water finds exit. Each plug is 

 surrounded by a length of larger stand pipe setting 

 loosely on top of the distributing pipe, open at the bot- 

 tom and reaching to the surface of the ground, for 

 the purpose of keeping the dirt away from the outlet and 

 rendering it accessible at all times for inspection. The 

 pipes are connected with mains leading from a reservoir. 

 The water finds its way through all the outlets, filling 

 the stand pipes and slowly percolating to the roots of 

 the plants. The 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 Figure 24, which 

 also illustrates the manner of laying. 



