516 A. B. BEAUMONT 
this in mind an experiment was planned. The method used is described 
on page 502. The results are given in table 23: 
TABLE 23. Errect or ALTERNATE WETTING AND DRYING UPON THE AMOUNT OF HumuUS 
EXTRACTED FROM A CLYDE SoiL 
Per cent of 
Soil treatment humus 
extracted 
Continuously ‘moisteie te ie aS eae Seis hans li st eg oe 4.40 
Anr-dried!letime ase hoe ke a ORAS EA IRE REY ar 4.42 
Fae aac ne Oy aie AU Aarti a Set teaew seer pe Neg REM a og 4.44 
2 UT Sana NN Secu Ne mua ws Se eee COMMA RO ROLNA GCSE | bo 4.34 
Sorte) Oc ae U aals aeidiero sb bug Ole Ta Nas dies all ane aoc ae 4.48 
Sig Pa ANA URS RA Caravan ONL eet Ra ty ee a Eee i 4.18 
The differences are not great enough to warrant drawing a conclusion 
that the moisture changes affected the amount of humus extracted by 
this method. It is very likely that the treatment, as the purpose for 
which it was designed would lead one to believe, took out all the humus. 
The extraction by this method is probably so thoro as to mask any small 
differences that might exist as a result of moisture changes. 
The data given in table 24 were obtained by comparing, colorimetrically, 
distilled water extracts, which were filtered thru a porcelain filter. The 
TABLE 24. Rewative INTENSITIES OF WaTER ExtTRAcTS OF DUNKIRK AND CLYDE 
SURFACE SOILS 
Soil Moist Air-dried Difference 
Dunkirkisurfa cetacean sy ee, Nae dei 50 20.8+2.5 29.2+2.5 
Ely dessurta ceri ea ese re eae ene 50 QSE0).7/ 41.0+0.7 
results show that air-drying these soils has increased the solubility of the 
coloring matter of the humus, if not the humus itself. 
This increase in solubility of humus material probably accounts in a 
measure for the growth of molds, after several wettings and dryings, on 
the soils that contained humus, 
