The St. Charles herald. [volume] (Hahnville, La.) 1873-1993, 1921-05-14
Bureaus 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 tnat
it 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 COM
position of coal, the origin of its con-
stituents, the transformation they nave
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
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 10
clear up some Of the confusion that
exists and to get a more exact knowi-
edge of the nature of coal In general
as well as to obtain certain fundamen-
tai facts, has been conducting at its
Pittsburgh station a 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
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
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-
tening the coal with reagents and then
cutting it into thin sections with NIL
crotome. But this changes the coal
too. much to show its true appearance,
besides the method is inexpedient.
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
! planned and polished on one surface
which was then cemented to glass
! slide with a mixture of Canada balsan
and marine glue. The piece was grounc
to q safe thickness on lapidary's
wheel and was finally ground to trans
parent thinhess by hand on fine hone
Examinations were then made through
the microscope at magniications rang
ing up to 1900 diameters.
The bureau says that even with tht
naked eye bed of any bituminou'
/ coal is readily seen to be banded, arc
chunk of coal is seen to be highl!
i iaminated and composed of layer!
/ varying greatly in thickness and II
| color, texture and fracture.
There are generally recognized ant
described two kinds of coal with re
| spect to its texture; compact coal ant
mineral charcoal or mother-of-cOal. II
the compact coal, in general, two kinds
of bands are recognized, apparent.
alternating and in sharp contrast. Tn
one is of a bright jet-black, pitchy ap
pearance and breaks with a conchoida
smooth. shiny fracture. The other i
grayish black, of dull appearance
and breaks irregularly. The former 1
generally called bright coal' or .glan
| eoal'' and the latter "dull coal" 2
.matt coal' The bright coal cons