508 A. B. BEAUMONT 
TABLE 14 (concluded) 
Per cent of 
Soil Treatment water vapor Difference 
adsorbed 
Air=d ried] ses ees eee eee 3.98+0.03 
0.27+0.04 
Dunkirk subsoil Ovensdriedie: Saye sees s ee 3.71+0.03 
; 0.930 .04 
Lenitedias ace errs Lat. Sig eae 2.78+0.03 | 
ATT=Onied etn te eee Ee 13.20+0.08 
0.40+0.09 
Vergennes subsoil Oven=dried: gee ue i en. ae 12.80+0.08 
3.69+0.04 
Tonitede esse ane ea eee | 9.11+0.02 
The following points are shown by the above data: (1) Igniting soils 
does not destroy their ability to take up moisture from a more or less 
saturated atmosphere, contrary to frequent assertions that it does. In 
fact, some of the ignited soils have rather high hygroscopicity. (2) The 
differences between air-dried and oven-dried conditions are smaller than 
those between oven-dried and ignited conditions. (38) The hygroscopic 
values of the soils richest in humus, the surface soils, have suffered 
the most by ignition. 
Effect of long immersion in water—— Soils that were continuously air- 
dried were compared with the same kinds of soils that had been air-dried 
and then covered with an excess (200 per cent) of water for two years. 
The soils that had stood under water were again air-dried before being 
compared with those that were continuously air-dried. The results are 
given in table 15. 
The differences, which are significant in each case, are not in the same 
direction. The long soaking has increased the adsorptive capacity of the 
Dunkirk soil, perhaps by a hydrolysis of the inorganic constituents, 
producing the colloidal condition. 
The decrease in the adsorptive capacity of the Clyde soil can be 
accounted for by the decomposition of the colloidal organic matter, which 
was contained in this soil to a greater extent than in the Dunkirk soil. 
This decrease in colloidal content may override any increase thru 
