Evening star., 1931-06-18
BY CALVIN GODDARD,


Professor Of Police Science. Northwestern
University School Of Law and Director
Of the Scientific Crime Detection Labora-
tory.
(copyright, 1881. by the Associated Press)
CHICAGO. June 18.-During the last
few years much attention has been at
tracted to developments in the field OF
firea-m identification, or, to use a more
comprehensive definition, the identif1-
cation of the particular weapon which
has fired a given bullet shell, wad or
charge of buckshot
The proper technical term to be ap-
Piled to Investigations of this type is
forensic bcllistics," or legal ba,listics. "
Forensic ballistics or the application
of ballistic knowledge to questions in
dispute at law, is. in its most important
applications, much more of an art than
science. Its value rests upon the
readily established fact that no two
similar things, whether large or small,
man-made or naturally created, are
identical down to their last microscopic
details. If this holds for firearms, as
it does, and provided every weapon
transmits certain markings to bullets or
shells which 1t fires, which it does,
these markings should be character
istic of that particular arm, and differ
slightly or materially, from those i'm
parted by any other arm, whether OF
IIle same OF L1ldI G1lLS
is true thousands of experiments have
proven.
knowledge Still Lacking.
But knowledge that this fact exists
Is far from being sufficient to make us
experts in the field. We must know
what markings are left on bullets as
they pass through barrel, and why;
how and why these differ from mark
ings left by other barrels Of the same
and unlike makes, and how and why
even two bullets fired in succession
through the same barrel will manifest
certain variations one from the other,
ordinarily Slight but sometimes quite
marked.
To acquire this knowledge we must
be familiar with the technique of fire.
arm and cartridge manufacture as
employed in the different factories
throughout the United States and
abroad. We must have at hand thou
sands of unfired bullets, loaded cart
ridges, empty. shells, in every current
caliber, make and subclassification, as
well as in any obsolete type that may
be available, not to speak of samples Of
every kind of modern and obsolete
powder cbtainable.
Added to these we need specimen
bullets of every caliber and type fired
through known makes of arms and filed
for comparison purposes, and as COM
preSensive as possible collection Of
the different makes and models of arms
themselves, quite apart from the fac
tory specifications governing the manu-
facture Of all weapons now in use.
With this reference library as
foundation, we must next acquire the
necessary instruments Of precision,
microscopes, micrometers, scales, photo
graphic apparatus ETC., before we are
n
identification.
Ability Put to Test.
When I say that this work is more
Of an art tnan science I mean that
In the last analysis we reach our con-
clusions not so much through the ap-
plication of some of the basic sciences
as through the comparison beneath
a microscope especially designed for the
purpose of two objects for the SIM
ilarities or dissimilarities which they ,
may exhibit Ability to recognize
fundamental similarities in two bullets
or shells, one known to be connected
with a murder and the other fired for
comparison purposes in the weapon
suspected, may be acquired only after
long apprenticeship and familiarity with |
the causes which produced the effects |
studied.
Two bullets from the same weapon |
recognized as such by one trained in
the art may, to the casual observer, |
appear extremely dissimilar while the |
converse holds equally true Hence the |
proficient student Of forensic ballistieS |
must have learned to differentiate be- |
tween markings casually present on bull |
let or shell, which through the opera |
tion Of transient causes may vary from |
time to time for the same weapon, and |
those permanent ones which are SUBJ |
ject to but little modification and which, |
when present on two exhibits under OBJ
servation, indicate identity of origin |
g. e., that these came from the same
ARM. Attempts on the part of made |
Quately trained persons to make such |
differentiations are extremely danger |
Gus and likely to result in errors which |
tend to cast disrepute upon the work |
in general.
Importance Is Recognized.
The police departments of many Of |
our larger cities have already become
alive to the Importance of scientific |
flrearm Identification, and several have /
already installed, or plan to install, bu- |
reaus for this purpose. The scientific /
crime detection laboratory in aff1liation
with Northwestern University, Chicago,
has just concluded course of instruc-
ton for student body composed of po-
lice officers from all over the country, in |
which the subject of forensic ballistics |
was heavily stressed. This, the first |
course of its kind in America, was so
well received that the plans are now
under way to repeat it twice.