Okolona messenger. (Okolona, Miss.) 1900-current, 1921-04-21
Bureau Of Mines Conducting Mi
CroSCopiC Investigation at
Pittsburgh Station.
old TESTS ARE UNRELIABLE
Reinhardt Thiessen, Research Chem
list, Says Scientists of the Past
Only Had a Vague Idea of
the Composition of Coal.

NEUTRALITY-SUSPICIOUS. Of the or
igin, composition and general nature
of coal held by scientists in the past
are so different and contradictory that
1t is difficult matter to determine the
real extent of knowledge available or
to rely on the literature, says Rein
hardt ThieSSen, research chemist of
the bureau of mines. Scientists in gen.
eral had only vague idea Of the COM
position of coal, the origin of it's con-
stituents, the transformation they have
undergone, and the conditions they
now are in.
The chemist did not have enough
fundamental knowledge to attack it's
chemistry in the right directions. The
fuel engineer, In turn, did not have a
broad enough chemical basis for stud
les in combustion, diStillation, cooking
and other processes relating to the use
of coal, hence the efficient utilization
of coal in the industries has suffered
from the lack of proper knowledge
of the nature of coal itself.
The bureau Of mines, in order to
clear up some Of the confusion that
exists and to get more exact knowl-
edge of the nature of coal in general,
as well as to obtain certain fundamen-
tai facts, has been conducting at it's
Pittsburgh station microscopic study
of the structure of coal. One of the
great hindrances to it's study, from the
time Of the earliest investigators to
the present, has been the difficulty in
thin sections for microscopic
observation. Many attempts had been
made to overcome this difficulty, and
also to devise other means of study.
For number of years the ash meth
cd was pursued, bits of coal being Ell
Their totally or partly burned and the
ash examined under the microscope.
Later, maceration was tried with some |
success, but on the whole 1t failed to |
reveal the true nature of coal. More !
recently the method was tried of sof- !
.ening the coal with reagents and then
cutting 1t into thin sections with a mi
But this changes the coal
90 much to show Its true appearance,
besides the method is inexpedient.
Used Rock Method Study.
For the bureaus work an adaptation
# the method used successfully for
ears by petrologlsts in studying rocks
md paleobOtanists in studying plants
vas employed. A small rectangular
'iece Of the coal to be examined was
'laned and polished on one surface,
which was then cemented to q glass
Tide with mixture of Canada balsam
nd marine glue. The piece was ground
0 safe thickness on a lapidary's
1heel and was finally ground to trans
aren't thinness by hand on a fine hone.
were then made through
he microscope at magnifcations rang
lg up to 1000 diameters.
The bureau says that even with the
aked eye a bed of any bituminOus
Oal is readily seen to be banded, and
chunk of coal is seen to be highly
and composed of layers
arying greatly in thickness and In
DIOR, texture and fracture.
There are generally recognized and
two kinds of coal with re-
)ect to its texture; compact coal and
neral charcoal or mother-of-coal. In
lie compact coal, in general, two kinds .
bands are recognized, apparently :
ternating and In sharp contrast. The !
he is Of bright jet-black, pitchy APP Z
'arance and breaks with a conchOldal y
nOOth, shiny fracture. The other is 2
ayish black, Of dull appearance, a
Id breaks irregularly. The former Is O
morally called bright coal" or ''glanz n
al" and the latter "dull coal' or 4
natt coal" The bright coal consists v