FOR BETTER CROPS IN THE SOUTH 97 



of where you intend to dig the ditch, by the side of which is 

 driven a guide stake which should stand about a foot high, and 

 should be labeled or numbered beginning at the outlet. 



Finding the Grade— There is very little complicated engi- 

 neering work connected with laying out a system of tile drains 

 on the ordinary farm land, but when the thousands of dollars 

 that have been wasted through a lack of proper laying of tile 

 are considered, the importance of following some correct method 

 of finding the grade is apparent. If you do not have a farm 

 level, or are not familiar with the handling of this instrument, 

 it would be advisable to employ a competent engineer to lay out 





Fiji. 5 



your tile drainage system. The extra expense of the engineer 

 is a very small percentage of the total cost of the tile drain, so 

 small, in fact, that one cannot afford to risk laying the tile 

 improperly. The method of securing the grade, as outlined 

 below, will assist the farmer who attempts to use a level of his 

 own, and for this reason it is made as simple as possible. Like 

 other methods, it is subject to some error, but if carefully 

 executed, the percentage of error will be small, and it has in its 

 favor the strong point of simplicity. 



Starting at the outlet, take the elevation of the hub at that 

 point, which we will call Station 0. We will consider this as 



^---■----..ife^fe^r^-r 



TUVEL 



After the final hubs have been set 



the datum plane, or in other words, will figure all other eleva- 

 tions from this point. Next get the elevation of Stations 1, 2, 

 3, 4, etc. As you will note in Figure 5 an example has been 

 worked out giving the different elevations at each point. For 

 instance, the elevation of Station 1 is one inch higher than 

 Station 0, Station 2 is four inches higher, Station 3 six inches 

 higher, and Station 4, twelve inches higher than Station 0. You 

 will note that the distance ;f rom Stations to 4 is two hundred 

 feet, giving a fall of three inches every fifty feet. With this in 

 mind we will start at the outlet, and set the final hubs. By 

 the use of a surveying instrument, drive the hubs at the vari- 

 ous stations until- they are the following distances above the 



