224 Agricultural Bacteriology. 



will not be flooded. The opening of the overflow should" 

 extend to the surface and be protected by a screen, thus 

 allowing air to pass in and out of the drains. 



The two compartments can be made of different 

 depths if desired. The first can be increased in capacity 

 by increasing its depth; this also serves to aid in main- 

 taining a constant temperature in the sewage. The sec- 

 ond division can be of less depth, thus aiding in obtain- 

 ing .the necessary fall where the slope of the ground is 

 slight. 



Such a disposal plant will work for a number of years 

 with no attention except the emptying of the second com- 

 partment at regular intervals. If the drains run be- 

 iieath the garden, a constant supply of moisture and of 

 plant food is supplied to the plants. 



