ent. Applying this rule,
illustration 341 is a tented arch, referenced to a whorl. Figures 342
and 343 are loops, referenced to whorls. Figure 344 is a plain arch,
referenced to a loop.

No set rule can possibly be devised to enable a classifier to know
with certainty where to draw the line when it is doubtful which
classification should be given such a print. Individual judgment is
the only standard. The test is: _if the pattern, in the opinion of the
classifier, is rolled to only a normal width, it should be classified
as it appears. If it seems to be rolled to a width beyond the normal
degree, it should be classified as if rolled only to the normal
degree_. Age, weight, size of fingers (as seen in the plain
impressions), heaviness of the ridges, and experience of the
technician in taking fingerprints are all factors in arriving at the
correct conclusion. The necessity for exercising the utmost care in
dealing with this type of pattern cannot be too highly emphasized.

[Illustration: 345]

[Illustration: 346]

The patterns in figures 345 and 346 also have a second loop near the
edge of the impression. In these two patterns, however, the second
loop is very near the delta and consequently will almost invariably
appear even though not rolled to the fullest extent. The foregoing
rule is not applied to this type of impression. Both are classified as
a whorl and referenced to a loop to take care of the rare contingency
of nonappearance.

CHAPTER IV

_The Classification Formula and Extensions_

_The classification formula_

At this point it is necessary to mention that when prints are
classified, markings are indicated at the bottom of each finger block
to reflect the type. The following symbols are used:

- Under the index fingers the appropriate capital letters
should be placed for every pattern except the ulnar loop.

- Under all other fingers, the appropriate small letter
should be placed for every pattern except the ulnar loop and
the whorl as follows:

Arch a
Tented Arch t
Radial Loop r

- Ulnar loops in any finger are designated by a diagonal
line slanting in the direction of the loop.

- Whorls in any finger are designated by the letter "W". The
classification formula may be composed of the following
divisions:

1. Primary
2. Secondary
3. Subsecondary