The Fayette falcon. (Somerville, Tenn.) 190?-current, 1921-04-22
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 a vague idea Of the CON-
position of coal, the origin of its con-
stituents, the transformation they have
undergone, and the conditions they
now are In.
The chemist did not have enough
fundamental knowledge to attack its
chemistry In the right directions. The
fuel engineer, In turn, did not have a
broad enough chemical basis for stud
ies 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 its
Pittsburgh station microscopic study
of the structure Of coal. One Of the
great hindrances to its study, from the
time of the earliest investigators to
the present, has been the difficulty in
preparing 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
ther 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-
tening the coal with reagents and then
cutting 1t into thin sections with a mi
crotome. But this changes the coal
too much to show its true appearance,
besides the method is lnexpedient.
Used Rock Method Study.
For the bureaus work an adaptation
of the method used successfully for
years by petrologists in studying rocks
and paleobotanists In studying plants
was employed. A small rectangular
piece of the coal TO be examined was
planed and polished on one surface,
which was then cemented to glass
slide with mixture of Canada balsam
and marine glue. The piece was ground
TO a safe thickness on a lapidary's
wheel and was finally ground to trans
parent thlnness by hand ON a fine hone.
Examinations were then made through
the microscope at magnlficatlons rang
ing up to 1900 diameters.
The bureau says that even with the
naked eye a bed Of any bituminous
coal Is readily seen TO be banded, and
a chunk Of coal Is seen TO be highly
laminated and composed of layers
varying greatly IN thickness and In
color, texture and fracture.
There are generally recognized and
described two kinds Of coal with re-
spect to its texture; compact coal and
mineral charcoal or mother-of-coaL In
the compact coal. in general. two kinds
Of bands are recognized. apparently
alternating and in sharp contrast. The
one is Of bright jet-black. pitchy APP
pearance and breaks with conch0idal
smooth, shiny fracture The other is
grayish black, OF dull appearance.
and breaks irregulariy. The former is
generally called bright coal" or ''gianz
coal" and the latter dull coal" or
matt coal" The bright coal consists