The Constituents of Banded Humic Coal. 
173 
LITHOLOGICAL INGREDIENTS IN BRITISH HUMIC GOALS — (Contd.) 
Vi train. 
Clarain. 
Durain . 
Fusain . 
Liability to 
spontaneous 
combustion 
Large ulmin 
content and 
fragile — hence 
has the great- 
est tendency 
to spontaneous 
combustion 
Large ulmin 
content favours 
but fairly hard 
nature operates 
against spon- 
taneous com- 
bustion 
Small ulmin 
content and 
hard nature 
are against 
spontaneous 
combustion 
Porosity 
favours 
oxidation and 
therefore 
spontaneous 
combustion 
‘ Caking ' 
properties and 
type of coke 
vitrain and clarain fuse and 
‘ cake ’ at ‘ low ’ temperatures 
— an essential to the formation 
of large pieces of compact coke ; 
the coke of vitrain is very 
porous and swollen, that of 
clarain more compact and less 
swollen 
non-caking 
(unless 
hydrogenated) ; 
coke usually 
powdery ; a 
‘ free burning ' 
fuel (for 
steam-raising, 
etc.) 
non-caking ; 
coke usually 
powdery ; 
calorific 
value high — 
a valuable 
powdered fuel 
Absorption of 
water vapour : 
1 day 
2 days 
4 dzys 
20- 3% 
21 - 2 % 
23-5-24-3% 
9 -i% 
10 - 0 % 
11 -3-12-5% 
4 - 9 % 
5 - 2 % 
5 -9-7-0% 
Ash present 
(see also 
proximate 
analysis, 
above) 
least ; mainly 
or wholly de- 
rived from the 
plant tissues ; 
calcium sul- 
phate and 
much magnesia 
and alkalis ; 
low in silica 
and alumina 
little ; mainly 
or wholly de- 
rived from the 
plant tissues ; 
calcium sul- 
phate and 
much magnesia 
and alkalis ; 
low in silica 
and alumina 
generally lar- 
est • includes 
much silica and 
alumina ; low 
in magnesia 
and alkalis ; 
largely repre- 
sents detrital 
mineral matter 
often large ; 
varies in 
amount and 
1 composition ; 
crystalline 
matter, especi- 
ally calcium 
compounds 
from percola- 
ting solutions, 
may be present 
Biological 
contents (seen 
in thin slices, 
etc.) 
pseudomorphs 
of wood and 
fibres only 
seen ; cells are 
completely 
disorganised, 
forming ulmic 
acid 
chiefly 
cuticles, some 
spores, frag- 
ments of wood 
and soft tis- 
sues, embedded 
in ulmic acid 
chiefly 
spore -cases and 
cuticles of 
leaves ; cell 
cavities filled 
with ulmic 
acid 
Crushed 
carbonised 
wood — and 
fibre — cells, 
with empty 
cavities 
Deductions as 
to conditions 
under which 
remains decayed 
under 
water 
under 
water 
under 
water 
at surface 
of water 
Deductions as 
to accumulation 
of debris 
mainly 
in situ 
mainly 
in situ 
mainly 
by drift 
mainly 
in situ 
1 933 August 1 
