Evening star. [volume] (Washington, D.C.) 1854-1972, 1927-01-16

| GROUP AT THE DOOR"
/ this, for better heads We're at their
disposal
The chief of the detective service
merely took up a telephone and called
up one of the assistant professors of
| the department Of criminology of
nearby university. TO him he COM
municated the few facts that the po-
| lice had in the case.
Where have you got the penknife
| now?" asked the scientist.
I'm the drawer of my desk"
Take a newly washed linen hand
kerchief and wipe that drawer with
| 1t. Then wrap the penknife in a bit
| of oiled paper, the handkerchief in
| another and send them both up here.
When the knife and the handker
| chief arrived at the laboratory of the
scientist he first took out the hand
| kerchief. On it's otherwise fresh
| white were sharp smears of dust that
! came from wiping the bureau drawer.
Some of this dust the scientist got
| on to a moistened microscope slide by
| Tipping the handkerchief with his
| hngernail, so that the flying particles
adhered to the moisture on the slide.
| Studying this under the microscope
lens, the scientist noted down the ma
ture or the dust particles.
What he found thus was to be used
as a negative factor--all such dust
would be disregarded in the inyestiga-
| ton thereafter, as coming only from
the bureau drawer at police head
quarters.
Then, with a fine screwdriver and
pliers, the scientist carefully took the
| penknife apart. No Swiss watch
! maker could have worked with greater
delicacy than that scientist unscrew
ing the tiny threaded bits of steel that
held the blades of the penknife.
He worked with a sheet of white
paper under the knife, the surface of
the paper oiled and fine to offer no
pores down which the dust could hide.
AS with all penknives that have
| been carried about in ones pockets,
dust showed on all parts that did not
rub against something. There was
| dust in the grooves into which the
| blades closed, dust in the hinges Of
| the blades. dust of the finest had FL
| tered even between the tightly screwed
together parts.
Then began a minute analysis under
| the powerful microscope, and with
chemical reagents and comparisons
| with photographs or other dust par
| ticles made through miscroscope
of Vienna possess.
And from this analysis a. series OF
deductions were noted down, not only
by the scientist but also by colleagues
| from other departments called in by
him.
! What helped the analysis was the
/ ascertained fact that the penknlfe had
been manufactured only a day before
| it was stolen. That meant that little
Il 4IaaN SSir m
/ of the knife was accumulated IN the
| pockets of the original owner.
! EIRST was examined the dust found
between the tightly pressed plates OF
| the sides and under the screw heads
! of the knife. To get into these places
| the dust had to be minute; indeed, the
| broken down siftage of the coarser
dust of the pockets in which the KnlIe
was carried.
Fine exclaimed the man with his
eve to the barrel of the microscope.
Either the man had the lining of his
coat pocket torn on he wore a coat
! which had no lining TO his pockets. /
hope it's the latter"
'sHow do you deduce that?" asked
the Vienna detective. who was watch
ing the analysis.
/ "Why, the oldest dust--the dust that
! has been broken up SO fine by con
slant friction and deterioration that
/ IL has sifted in between the plates OF
The knife--consists mostly of minute
particIes of wool. That would be from
the uocket where the knife was most
carried.
eff the man had carried the knife
in his trousers pocket, which is al
WAYS lined, the particles would he
of cotton since that is what pocket
lining is made Of, with infrequent
exception.
But since what we have here is
the dust of wool it means that the
rocket was in the coat; and that
either, as 1 said, the pocket lining
was torn and the knife had slipped
through to the bottom of the coat
next to the wool itself or the pocket
was unlined.
~ ct us see--no there are no par
tic|es of cotton there at all. | should
say then that the pocket was of the
patch variety But patch pockets
are made only in sporting suits OF
{ what is known as the Norfolk style
with belt in back.
Now, let us look again at the WOO
uarticles. There seems to be roughly
about so per cent black particles, 81
white That would say to me the. coat
was either black and white checkered
or what Is known as pepper and
salt
He addressed the detective: "Wn
YOU have your men go TO the class
10 tailors that make or sell this type
of Norfolk suits and bring q collec
ton of wool samples of black and
White mixtures"
y x
q
| "A quarters started that search. By
next morning a collection such as he
had asked for was at the scientist
disposal.
] From each sample he obtained WOO
particles and compared them with the
findings of the day before. FINALLY
he smiled.
Here is the exact pattern, he said
pointing to a cut of English tweed