Plate 2. — Soil displacement apparatus, 

 consisting' of a battery of brass tubes, 17 

 inches length and 3 inches diameter. A brass 

 screen rested on the bottom of each tube. Soil 

 is packed very carefully in the tubes and 

 water placed on top of the column of soil. Air 

 pressure is applied as necessary to effect dis- 

 placement of soil solution. (From BuRD and 

 Martin, unpublished). 



