Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-02-10
ern Science Plays Vital Part in Many Crime Convictions

I ranged from O.339 to 0.340 millimeters.
| The diameters of test shells shot from
the same gun were Of similar size.
However, unfired shells which fitted
the same weapon measured from 0.335 to
0.337 millimeters in diameter. The diff
ference in shell diameter before and
| after firing amounts in some cases TO
as much as ten-thousandths of an inch.
If a bullet under magnification shows
only one distinctive rifling mark, the ex-
pert ~criminologist can build up a con-
| elusive case adequate to bring about a
| conviction from this wisp of evidence
which is invisible to the naked eye.
Bullets which are deformed, mush-
roomed or with rifling marks obliterated
are practically valueless in modern
crime detection, as about all the inves-
tigators can do with such exhibits Is to
weigh them on delicately balanced
scales.
Cartridge shells ordinarily are excel
lent evidence for display in court, the
only disadvantage being that they will
corrode or oxidiZe when exposed for
any considerable period to weathering.
| Generally, If the shells are recovered
within one to two weeks after the
crime, they are satisfactory as valuable
clues which may lead to the discovery
Of the murderer. The same systems OF
Identification are applicable in the case
| of shotgun shells as with rifle ammuni-
ton except that no rihing marks are
present in the former case. The most
conclusive results are obtained with
jacketed bullets fired from an auto
matte rifle o. revolver, but even COM
mon lead bullets bare their secrets
when studied exhaustively by modern
experts. They all aid measurably in
divulging the secrets EMBODIED in intri-
cat murder mysteries which skilled
sleuths delight in ferreting.
1t is delicate work making plaster Of
Paris molds Of gun barrels, but even
such remarkable consummationS have
aided in ~unraveling certain complimated
crimes. In making n of these molds
the interior of the gun barrel is first
coated with a thin film of vaseline.
Then the plaster is applied and, sub
Sequently. Is removed intact after hard
ening. Such a plaster model Of a gun
barrel is invaluable as it a be ex-
amined directly under the high-power
microscope. while 1t IS also useful l n
making precise measurements Of the
lands and grooves and other rifing
marks.
y X X X
DOLCE department officials, private
detectives and independent GRIM
nologists are frequently obliged to
prove the fraudulent character of
forged documents which figure in muir
der cases. 1t is a relatively simple
matter for one skilled in the detection
OF fraudulent checks, forged wills or
other legal documents, to determine and
demonstrate the illegitimacy Of such
papers. If a moist, clean white blotter
Is pressed against any specimen Of
handwriting which has been tempered
with for two hours in a letter press, the
last writing which was entered will be
Imprinted on the blotter while the
original writing will not transfer.
Ink eradicators commonly used by
dishonest folks with criminal intent
are nothing more than chemical re-
agents which bleach out the original
writing or figures and facilitates the
insertion Of new text OF totals. The
experienced chemist, by treating doubt
full documents with special chemicals
can restore handwriting obliterated pre-
viously with ink eradicators. Then the
writing and Ink employed In the two
specimens OF chirography car be studied
under ultraviolet light and even photo
graphed. One ink will be bright and
readily discernible while the other will
be faint and IN some cases almost illegi-
BILE. Complex crimes have been solved
by these expedients which are simple
from the viewpoint of the chemist, but
which are rather amazing to those who
see these tricks Of detection in operation
forethe FIRST time.