4 BULLETIN 802, E. S. DEPARTMENT OE AGRICULTURE. 
behavior of the various types of disintegrating plant remains making 
up a peat deposit, are considered of special importance in drainage 
projects intended to be practicable from an engineering and agri- 
cultural standpoint : they are essential for an adequate method of 
dewatering peat materials that are found to be of value for manu- 
facturing purposes. It is rather in the knowledge of the different 
kinds of peat material, the factors in the field which brought about 
their accumulation and determined their character, that a satisfac- 
tory basis has been found for the improvement of peat by means 
of suitable crops or by specific operations in the technical industries. 
Few phases of botanical inquiry have received as much attention 
as the development and formation of peat deposits: yet information 
concerning them appears to be little known and still less considered 
in practice, though the classical investigations of Andersson (l), 1 
Clements (-1), Graebner (12). Lesquereux ( 16). Lorenz (17).Potonie 
(19). Sendtner (21). Sitensky (22). and especially the works of 
Friih and Schroter (10). Grisebach (13). Steenstrup (4). Yaupell 
(23). and TTeber (25) are not only comprehensive but fundamental 
in problems relating to the structure and content of peat deposits. 
The attempt to establish a correlation between vegetation and any 
one factor of the environment is difficult, and though not all field 
work is of a nature adapted to throw light on this vexed question it 
has. nevertheless, been possible to make such a correlation in the lines 
of physical and chemical studies with types of peat material distinct 
in botanical composition and in degree of disintegration. Practically 
all the work is thus far European, and the leading investigations, 
notably those of Bersch (2). Birk (3). Feilitzin (9), Gully (1-4), 
Hoering (15). Minssen (18). Virchow (24), and Zailer and TTilk 
(26-27). follow for the most part modern botanical viewpoints and 
definitions. 
The botanical, physical, and chemical nature of the different 
peat materials is of the widest practical importance, since it is in 
general more difficult to change the nature of the vegetable mass 
than to remedy its deficiencies, but almost equally important is the 
character of the mineral soil underlying the plant remains. The 
geological relations have their most important significance in the fact 
that decaying organic matter and carbonated water have a relatively 
high solvent action on the minerals of soils and rocks. This effect 
increases with the area covered by the accumulating masses of peat 
materials and especially with thicknesses in which oxidizing condi- 
tions are absent. Underlying and marginal soils derived from sedi- 
mentary, metamorphic. and eruptive rocks, both basic and acid, 
correspondingly affect the content and quality of peat materials in 
1 The serial numbers in parentheses refer to "Literature cited" at the end of this 
bulletin. 
