The Science of Fingerprints: Classification and Uses — John Shaqi
The Science of Fingerprints: Classification and UsesUnited States. Federal Bureau of Investigation
Science
The Science of Fingerprints: Classification and Uses
United States. Federal Bureau of Investigation
Fingerprints
Figure 300 is shown for the purpose of explaining that in the whorl,
as this print is, appendages at the top of the recurve will not spoil
or affect the recurve. Hence, the impression is a good whorl of the
central pocket loop type and needs no reference.
Figure 301 is classified as a whorl of the double loop type. There are
present two distinct loops and two deltas (the right delta is not
present as the impression was not rolled sufficiently). The pattern is
unusual because the loops are side by side and flowing in the same
direction. The tracing is an inner tracing.
Figure 302 should present no difficulty. It is classified as a plain
arch for its ridge construction follows the rule of a plain arch,
i.e., "enter one side and flow or tend to flow to the other."
Figure 303 is a plain arch. The dot at the center is not elongated
enough to be considered an upthrust. A dot, even though as thick and
heavy as the surrounding ridges, is not considered for any purpose but
ridge counting or fixing a delta.
Figure 304 is a pattern somewhat similar to the previous illustration.
As indicated before, dots are considered as ridges only in ridge
counting and fixing a delta. This pattern, therefore, must be
classified as a plain arch, rather than a tented arch with two ending
ridges and a delta formation.
Figure 305, although showing an appendage upon each recurve on the
left side, is classified as a whorl of the central pocket loop type,
with two deltas and a recurve in front of each. To spoil the recurve
of a whorl the appendage must be connected to the recurve at the point
of contact with the line of flow.
[Illustration: 303]
[Illustration: 304]
[Illustration: 305]
[Illustration: 306]
In figure 306, the impression has two equally good loop formations. As
it has but one delta, it cannot be classified as a whorl of the double
loop type nor as a loop since it would be difficult to make a
preferential choice between the two looping ridges. It is arbitrarily
given the classification of a tented arch.
In figure 307, the difficulty lies in locating the delta. The only
ridges answering the definition of type lines (ridges running parallel
and then diverging to enclose the pattern area) have three ending
ridges between them. The type lines, the delta, and the core are
located as indicated. The pattern is classified as a six-count loop.
Figure 308 is classified as a tented arch, although it appears at
first glance to be a loop. Closer inspection shows that the looping
ridge does not tend to go out the side from which it entered but
rather seems to proceed downward ending in an abutment forming a
definite angle of 90 deg..
[Illustration: 307]
[Illustration: 308]
[Illustration: 309]
[Illustration: 310]
[Illustration: 311]
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