Grade 

 Date. 



(48) 



EXERCISE 18 

 Percolation of Water Through Soils 



Percolation is the passage of water througii soils by means of the natural 



channels. 

 Purpose. — To study the influence of texture and structure upon the passage 



of water through soils. 



1. Take six soil tubes (Fig. 13): fill three of them with the three different 

 soils to within one-half inch of the overflow pipe, pouring it in looselj\ 



Fig. 13. — Percolation 

 soil tube. In comparing 

 the percolation of water 

 through several soils 

 the tubes are placed in 

 the support block (Fig. 

 14) and are connected 

 by rubber tubing at- 

 tached to the lateral in- 

 lets. A beakeris placed 

 under each drainage 

 tube. 



Fig. H. — .'iuppurt block lor use in holding tubes with drainat;f outlets 



15. — Another .simple form of apparatus to show percolation of 

 water through soils. 



2. Fill the other three tubes with their respective soils, packing in the usual 



way by dropping or by using the compacting machine. 



3. After all the tubes are full place a layer of coarse sand one-half inch deep 



over the top of each. This will prevent the water as it flows from dis- 

 turbing the soil below. 



