210 Journal of Agriculture. Victoria. \ 10 Apkil, 1918. 



Plate 161 illustrates a longitudinal section of tiles in position under- 

 ground. 



A study of the different systems of drains figured in Plate 162 will 

 enable the reader to draw fairly accurate conclusions of the way the soil 

 water gravitates to the drains and is carried away in each instance. 

 Assume that, in the case of Fig. 1, the land is flat, and that the black 

 dots denote the positions of the trees. The land being level, the soil 

 water finds its way, as the six small arrows radiating from each tree 

 indicate, to the six lateral drains, the positions of which are marked by 

 the long arrows. These drains deliver the water into the larger head 

 drain or ditch, whose position and decline are indicated by the long- 

 arrow at the base. 



SuiTacey Level/ 



LONGITUDINAL SECTION 



Plate 161. 



It will be observed that the drains in the area shown in Fig. 2 are 

 similarly placed to those in Fig. 1, but as there is a decline in the direc- 

 tion of arrow (A), the water will be more inclined to find the lateral 

 drains, as depicted by the small arrows in this figure. 



The drained area appearing in Fig. 3 is in the sarpe plane as that 

 shown in Fig. 2, but in this instance a system of diagonal drains is 

 illustrated. The small arrows, under these conditions, also show the fall 

 of the water to the drains. Practically the same length of drains is 

 involved in the diagonal system as that shown in the square method, 

 which represents an area of similar extent, but as the tendency of the 

 soil water is to move from tree to tree before finding its way to the 



