July 15, 1924 
Chemical Examination of Peat Materials 
75 
"which in the course of time has been 
^altered by the addition either of en¬ 
crusting substances or of chemically 
combined noncellulose constituents. 
Hence the lignose materials in plant 
xemains are not definite compounds 
like cellulose, but vary in composition 
-owing to the thickening of the cellulose 
surface by adsorption of different sub¬ 
stances from the sap in trees, shrubs, 
and other woody plants. The compo¬ 
sition of lignin has not been definitely 
■determined; it is more resistant to 
decay and difficult to hydrolyze. 
Lignin is obtained by treating wood 
with strong hydrochloric acid in ac¬ 
cordance with the method of Will- 
statter and Zechmeister (52 ). The 
insoluble portion contains a methoxyl- 
yielding complex when treated with 
concentrated hydrochloric acid in the 
manner originally described by Zeisel 
(5 4)- Methoxyl (CH 3 0) has been 
determined in the wood of a large 
number of trees by Ritter and Fleck 
(87), while Shorey and Lathrop (48) 
found it present in the organic matter 
<of widely different mineral soils. But 
fhe fact that its occurrence bears a 
relation to lignocellulose tissue indi¬ 
cates that the quantity of methoxyl in 
fhe organic matter of mineral soils and 
in that of different layers of peat varies 
with respect to the kind of vegetation 
"that is the source of the lignose com¬ 
pounds, and with their persistence 
during the process of decay. As the 
decomposition of woody material pro¬ 
gresses, and the less stable cellulose 
disappears, an increase will become 
apparent in the methoxyl content. In 
“the Velen peat deposit, which has 
been studied by Fischer and his co¬ 
workers (13), the quantity of methoxyl 
in sphagnum moss peat is less than that 
in the woody layers of peat; the sedi¬ 
mentary organic material from greater 
depths shows a corresponding increase 
in the methoxyl content of the portion 
insoluble in acid. The results recorded 
by Fischer are important also in that 
"they show by the action of solvents a 
general agreement between the botan¬ 
ical composition of peat materials and 
their content in bitumen and in alkali- 
soluble material. The German inves¬ 
tigators point out that the methoxyl 
♦content does not vary necessarily with 
increasing depth but that it fluctuates, 
♦exhibiting, however, a tendency toward 
the attainment of a maximum value in 
woody plant remains. The results 
•confirm the earlier work of Rose and 
Xisse (40). 
Cellulose is very common in the 
plants from which peat is derived. 
There are a great many varieties of 
cellulose, and hence the term must be 
taken as denoting a group (6). Evi¬ 
dence of the existence of cellulose in 
peat materials has been obtained by 
von Feilitzen and Tollens (12). Com¬ 
parative analysis showed that the cel¬ 
lulose content decreases during de¬ 
composition. The samples contained 
from 6.64 to 15.37 per cent of cellulose, 
those taken from layers below the sur¬ 
face of a peat deposit yielding the 
smaller percentage. Sphagnum moss 
contained from 20.8 to 21.42 per cent 
of cellulose. 
It has long been known that cellu¬ 
lose could be broken down into reduc¬ 
ing sugar by treatment with acids. 
Keppeler (24) using a strong solution 
of sulphuric acid (72 per cent), devel¬ 
oped a method of hydrolysis for deter¬ 
mining the degree of decomposition of 
peat layers. Tests made with this 
method showed that sphagnum peat of 
recent origin is greatly hydrolyzed and 
hence has a very low degree of decom¬ 
position, scarcely exceeding 25 per cent. 
Samples of sphagnum peat of older 
origin were less strongly hydrolyzed, 
the degree of decomposition vary¬ 
ing between 70.9 and 78.8 per cent. 
Tests of the profile of a peat de¬ 
posit indicated that the degrees of de¬ 
composition increased with the depth 
below the surface of the deposit. A 
comparison of the Keppeler method 
with that of von Feilitzen (12) leads 
Gorbenko (15) to the conclusion that 
on peat materials of Russian deposits 
the Keppeler method is inaccurate and 
too complicated, probably owing to 
the differences in the profiles of the 
peat deposits and to the difficulty of 
removing the product of hydrolysis. 
More recently, Schneider and Schell- 
enberg (44) reported briefly on the 
action of different solvents for cellulose 
in peat. These authors observed that 
samples of various kinds of peat treated 
with carbon bisulphide and sodium 
hydroxide (Xanthogenic acid), or with 
the ammoniacal cupric oxide (Schweit¬ 
zer’s reagent) show a moderate solvent 
effect. The yields of insoluble residues 
are not materially less than those 
obtained by treatment with alkali 
alone. The cellulose of peat materials 
appears to be more resistant in alkalies, 
but the proportion of organic material 
soluble in alkali, referred to as humic 
acids, is much larger in the deeper and 
older layers of peat (45 ). The action of 
reagents such as ammonia and sodium 
hydroxide is noteworthy in that it 
points more clearly to the differences 
connected with the botanical compo¬ 
sition of the respective layers of peat. 
It would seem, therefore, that the 
