36 BULLETIN 495, U. S. DEPARTMENT OF AGRICULTURE. 



installed as the first part of the construction so that the posts for the 

 nozzle lines can be set-to correspond with the risers from the main. 



Kxca\ ating for the main can be facilitated by plowing and throw- 

 ing the loose materials out by hand. The second and following plow- 

 ings should be done with a narrow plow hitched to a steady horse. 

 The main pipe should be put together while lying on timbers across 

 the trench, so that each joint can be fitted easily and tightened. 

 Usually a section of 200 feet or more can be put together and then 

 allowed to sag gradually into the trench as the length increases. 

 There are two points where installation of a main feed pipe may 

 begin. If the pumping plant has been installed and careful measure- 

 ment has been made to the first lateral, the main can begin at the 

 pump. If there is an important branching of mains, then the start- 

 ing point can be at the branch or the first definitely located nozzle 

 line nearest the pump and the pipe then laid in two directions toward 

 the pump and through the field. The main pipe then can be cut to 

 fit to the pump or the pump set to fit the main with the aid of the 

 expansion joint and flange couplings. 



INSTALLING NOZZLE LINES. 



The first parts of the field system to be installed are the posts. 

 These should be located carefully to line up in every direction, so 

 far as possible, like trees in an orchard. The risers from the main 

 feed pipe should form the first post to each line and form a starting 

 point for measuring. It usually is advisable to locate the posts on 

 the two outside lines of the field and then one center line in which the 

 posts will line up with the outside ones. It is an easy matter then to 

 locate the remainder of the posts by intersection sighting. In the 

 case of wooden posts, the tops should be cut to uniform heights. 

 Posts made from pipe can be driven a short distance into the earth 

 in the bottom of a post-auger hole, and after they are lined up and 

 adjusted to a uniform height the auger hole about the pipe can be 

 filled with concrete. 



After the posts have been set in the field the bearings are fastened 

 to them and the sections of pipe placed on the ground along the side 

 of each line. Each nozzle line is then screwed together tightly, great 

 care being taken to remove all dirt and filings from each section. 

 Paint or lead should not be used on the inside of the joints, as such 

 material on the inside would cause clogging of the nozzles. It is 

 better to apply heavy graphite grease after the thread has been 

 started. When wooden posts are used, the pipe line is laid upon 

 60 to 90 penny spikes, one of which is driven firmly into the side of 

 each post. The spikes should be placed about 3f feet to 4 feet above 

 the ground, depending upon the height of the man who will do the 



