510 
A. B. Beaumont 
Data showing the effect of alternate wetting and drying of soils on their 
adsorption of methylene blue are presented in table 17: 
TABLE 17. Errect or ALTERNATE WETTING AND DRYING OF SOILS ON THEIR ADSORPTION 
Soil 
Dunkirk surface 
Clyde surface 
oF METHYLENE BLUE 
Corrected eee o 
colorimetric ye adsorbe Difference 
Treatment reading per gram 
of soil 
Continuously moist....| 53.5+1.7 | 4.870+0.004 
0.0800 .004 
Air-dried 1 time...... 135.0+1.4 | 4.950-++0.0005 
0.005+0.001 
Dik ian mete 125.0+2.4 | 4.945+0.001 
0.005+0.001 
Cape eta es 133.0+2.4 | 4.950+0.001 
0.000+0.002 
Ss co Ne ay ae 133.0+4.1 | 4.950+0.002 
0.0000 .002 
Geen ce ue 138.0+2.0 | 4.950-+0.0005 
0.000+0.001 
Yarn a eeac 131.0+2.4 | 4.950-+0.001 
0.030+0.001 
Oven-dried once....... 88.0-+0.0 | 4.920+0.000 
0.935+0.015 
Tonitedss.0eee.. Sere 6.8+0.1 | 3.985+-0.015 
Difference between 1 
drying, and 32/dryings|joce a. 2 crib sel eee 0.000+0.001 
Continuously moist....| 50.5+0.2 | 9.97+0.000 
*0.02+0.000 
Air-dried 1 time...... 115.8+0.6} 9.99+0.000 
0.000.000 
AAS bal Bec We) 133.0+0.6 | 9%.99+0.000 
0.000.000 
AR SB SLAaEA 155.8+2.6 | 9.99+0.000 
0.000.000 
Sine ie ame 146.0+2.C0 | 9.99+0.000 
0.000.000 
Ge aie ene. 140.24+4.8 |} 9%.99+0.000 
g 0.00+0.000 
Sots nein eee 151.542.2] 9.99+0.000 ° 
0.010.000 
Oven-dried once....... 92.8+0.6 9.98+0.000 
0.450.030 
Tomited te. skeen eat 3.1+40.0} 9.58+0.030 
Difference between 1 
dryingyand 32) dryings|) sree- score UL ee eee 0.00+0.000 
*In cases when the probable error of the mean is 0.000, separate determinations were so close as 
to make it negligible. 
