FORGED DOCUMENTS
Use of Microscope--Erasures--Photographic Methods--Typewritten
Matter--Examinations of Charred Fragments--Forgery of Bank Notes.
The most valuable methods of detecting forgery have been based upon the
use of the microscope, which will frequently reveal alterations that are
quite invisible to the naked eye.
For instance, a letter may have been so carefully erased as to defy
detection by ordinary examination, but a microscopical examination will
show the slightly roughened surface of the paper, where the fibres have
been disturbed in the process of erasure. A notable example of this was
seen in the Whalley will case, an account of which is given on a later
page, and numerous instances of the same kind have come under the direct
observation of the present writer.
In one of these cases, which was settled before it reached the courts, a
letter which was to be put in evidence in a dispute as to some property
had originally contained the words "your house," but the "y" had been
skilfully erased, so that the words read "our house."
When the paper was held to the light it showed an almost imperceptible
thinness at that place, but under the microscope the ruffled fibres on the
surface of the paper where the sizing had been scratched off, were very
noticeable.
Skilful forgers guard against this obvious sign of alteration by treating
the erased place with a solution of rosin in spirit, which leaves a fine
shiny layer upon the paper similar to that of the original sizing.
A treatment first with hot water and then with alcohol will remove this
coating of glue or rosin, and when the paper has been dried again it will
be found that this part, which will now be free from its protective layer,
will absorb a drop of water more rapidly than the rest of the surface.
Another simple test to reveal erasure is the use of iodine vapour, which
will often cause a blue coloration (due to starch) upon the moistened
surface from which sizing has been removed, but will only colour the
remainder of the paper brown.
This test gave a very pronounced result in the examination of the letter
to which reference has been made, in which erasure of the letter "y" had
been suspected from the general appearance and microscopical examination
of the surface of the paper.
The course of the tests described above should be followed under the
microscope, although in some instances the fraud is so extensive as not to
require any magnification. As a rule, however, it is preferable to use
only one drop of a reagent, and to follow closely under a low power of the
microscope, its action, both upon the material of paper and upon the ink
of any writing, which it may render visible.
The detection of mechanical erasure, which as was mentioned above, is
frequently indicated by the paper being thinner and more transparent at
that place, is often rendered more certain by photography.
Thus if the document on which was the suspected erasure is placed between
a strong light and the camera, the negative will show a darker area
corresponding to the place where more light was transmitted through the
paper.
A photograph taken in direct light would probably in such a case show
nothing, but in a negative taken with the light falling obliquely upon the
paper, the fibres that had been roughened by the erasure would be visible,
unless a subsequent treatment with glue or rosin had been used to conceal
the injury to the surface.
Ink applied to the surface of paper from which the sizing has been removed
will show more or less tendency to spread, as upon blotting paper, and
although this may be so slight as to escape the notice of the naked eye,
it will be plainly visible under the microscope, and on a photographic
enlargement the rough edges of the marks will be very pronounced.
Every little fault or attempt at touching up will be brought into
prominence, and in cases where writing has been removed by the use of
chemical reagents the slight yellow stain which is frequently formed upon
the paper--a stain so trifling that it would not ordinarily attract
notice--will appear as a dark blotch upon a photographic reproduction. It
has frequently been claimed that it is possible to distinguish between
different kinds of ink by means of photography. Since inks contain
provisional colouring matters which cause the dried pigment upon the paper
while apparently black to be in reality red-black, blue-black, etc., it
was asserted that such differences would be made manifest in photographs
taken on an ordinary plate, and still more by the use of colour-sensitive
plates.
The present writer, however, has been unable to confirm these statements.
It is true that differences in intensity appear upon the negative, but
these are not any more pronounced than the differences obvious to the eye
in the writing, and the use of special plates and screens does not give
any more satisfactory results.
The chief use of the photographic methods is to distinguish differences in
form rather than in colour, and to record them for purposes of
demonstration.
One direction in which photography is particularly useful is in
deciphering the words in faded ink upon old documents, for the yellow
colour of the ancient vellum is due to the formation of iron oxide.
Of recent years photography has supplied another valuable means of
detecting alterations in documents, and it has been found particularly
useful for demonstrating to a judge and jury the results of a
microscopical examination.
Photographic reproduction and enlargement has the advantage over chemical
methods of not producing any alteration in the ink or paper, and in some
instances is just as effective as the latter. In the examination of wills,
for instance, it is necessary to obtain the express permission of the
President of the Probate Court, before any chemical tests may be applied
to the document, and except under special circumstances such permission
would certainly be refused.
All the details of the writing and of the texture of the paper may be
recorded by the camera, and a photographic enlargement may then be made to
any required extent, so as to obtain what practically amounts to a record
of the microscopical appearance. And the process has the additional
advantage over microscopical examination that a large portion of the
magnified surface may be examined at the same time, whereas in studying a
document under the microscope, the view is restricted to a very minute
portion of the surface.
With the more general use of the typewriter it became possible to write
libellous letters with much less risk of detection than in the case of
letters written in ordinary pen and ink, for the machine eliminates the
personal characteristics of the writer.
The differences between various makes of typing ink are also less
pronounced than the differences between different kinds of writing ink,
and the proof of the identical character of two inks has, therefore,
usually less significance.
There are, however, certain typewriting inks, which are characteristic
from the fact that they contain finely-divided carbon, and are, therefore,
unlike most typing inks, exceedingly permanent, and it is also possible to
distinguish between the more common violet aniline inks by the different
degrees of resistance that they offer to bleaching reagents.
Although it is not possible to identify the writer of a typed document by
a study of the typing it is frequently not a difficult matter with the aid
of the microscope to identify the machine upon which it was written.
The principle underlying such identification is that the letters upon a
new typewriter are arranged at very nearly equal spaces from each other
and produce a fully horizontal line of writing. But after being in use for
a very short period some of the letters are certain to get out of
alignment, and to give faults in their relative position, which are
usually reproduced every time those letters are struck. Thus, for
instance, an "a" may be a little above the line and an "r" fall too much
to the right, and these peculiarities will almost invariably recur
throughout every scrap of writing done upon that machine, until the
alignment has been adjusted. In no two machines are exactly the same
variations in the relative positions of the different letters likely to
occur. The chances of this happening is exceedingly remote, for there are
some seventy letters and signs upon a typewriter.
A practical illustration of the value of the evidence thus afforded, was
seen in a case that occurred about a year ago. It was suspected that a
letter had been written in collusion with a clerk in a certain office, and
proof of this was thought likely to have considerable influence upon the
issue of the trial.
When this letter, which was in typewriting, was compared with another
letter that had unquestionably been written in that office it was found
that the faults of alignment in both were identical. Wherever a letter, or
combination of letters, in the one fell above or below the line, the same
thing occurred in the other, and wherever there was unequal spacing
between two letters the distances were invariably equal in both cases.
In addition to this, the ink, which was of the violet type, contained the
same pigment, and the watermarks on the two sheets of paper were the same.
There could, therefore, be no reasonable doubt as to the two letters
having been written upon the same machine. As a matter of fact, this proof
of collusion did not carry the weight that had been expected, for the case
was decided upon issues that were not affected by such proof.
With the aid of a measuring-scale upon the eyepiece of the microscope it
is possible to measure the thickness of strokes of writing only ten
thousands of an inch across, and in some cases to prove in this way that a
certain part of a document was written at a different time or with a
different pen than the remainder of the writing.
In attempting to reproduce a signature a forger will probably make a
preliminary outline with a blacklead pencil and then go over this with
ink.
The imperfect removal of the pencil marks may then betray the fraud, as in
the Whalley will case described on another page. In some instances the
particles of the graphite may be seen with the aid of the microscope to
project beyond the upper layer of ink.
Additions and alterations made to the letters in writing are clearly
visible when magnified, and may be demonstrated in court by means of a
photographic enlargement. Any irregularities in the edges of the letters
or any break between one part of a letter and another appear much more
pronounced when examined in this way, for all faults are enormously
intensified. Thus the figure "0" might be altered into "9" by the
addition of a stroke, or a "3" turned into an "8," but it would be
practically impossible to do this in such a manner as not to show when
slightly magnified.
The accompanying illustrations, for which the writer is indebted to Mr. A.
S. Osborn and the proprietors of _Knowledge_, will make these points
clearer. In Fig. A is shown the result of an attempt to change the number
"11" into "17" by the addition of a stroke to the top of the second "1."
The small inset represents the appearance of the fraudulent alteration,
while beneath it is seen the microscopical enlargement, in which the
joining of the added portion is plainly visible.
Occasionally it happens in fraudulent alteration of writing that a stroke
or part of a letter may touch some of the original writing, and betray
itself by being above instead of below the older letter.
Thus in Fig. B the words "in full to date" were added to the receipt after
the signature had been put, and it will be noticed in the enlargement of
the cross stroke of the "t" in "date" and the top of the capital "C" in
the signature (Fig. C), that the alleged older writing comes uppermost.
The point at issue in this dispute was whether the receipt referred to a
whole sum or only to a payment on account.
The writer in the course of his experience has seen many similar
fraudulent alterations, but has never met with a case like that described
by Mr. Osborn, where the perforations which are in common use as a means
of preventing fraud had been carefully filled in, and new perforations
made. Fig. D shows that a fraud of this kind may be detected with
certainty by the aid of the microscope, the edges of the original
perforations appearing as rings of a lighter hue.
[Illustration: ALTERED NUMBER]
[Illustration: ALTERED PERFORATION
Detection of Forgery by means of the Camera and the Microscope
_By kind permission of "Knowledge"_]
The subsequent addition of writing to a document was in one instance
detected by the fact that the paper had been folded before the later
writing was introduced, and in the crease thus formed the sizing on the
surface of the paper had become worn, leaving the fibres more porous. Here
the ink had shown a tendency to become diffused, and the blurred edges of
the lines thus produced were very manifest.
Even where paper has been so completely charred that no signs of writing
remain visible, it is frequently possible to render the characters visible
once more by continuing the incineration until only a white structure of
ash remains.
When the writing was originally in ink the characters will usually appear
in reddish-brown marks (due to the iron in the ink) upon the white
background of ash. In the case of inks that do not contain iron, or when
the writing was in carbon or aniline typing ink, this method of
incineration will prove unsuccessful.
Writing that has been done with an ordinary lead pencil can usually be
rendered visible by carefully regulating the heat during the incineration,
so as not to burn away the graphite. Marks done with a red pencil are, as
a rule, burned away with the paper, but blue pencil marks usually persist
owing to the presence of an iron compound in the pigment.
In the case of printing inks it is rarely possible to render the
characters visible again, except when, as in blue printing ink, some iron
pigment was present.
The limits of this method of reading writing upon charred paper have
recently been investigated by Habermann, who finds that a main essential
for the successful working of the process is that the paper itself shall
yield a coherent white ash. In the case of common varieties of paper,
especially printing paper, which are loaded with china clay and other
mineral matter, this condition is admirably fulfilled.
With pure rag papers, however, the ash is much less coherent and is too
small in quantity to leave a background. Even in such cases it is possible
to increase the amount and coherence of the ash by painting the reverse
side of the charred paper with a solution of a mineral fixative agent,
such as aluminium acetate. On now drying the paper and continuing the
ignition the added substance leaves its own white ash which binds together
the ash of the paper.
The fragments of white ash upon which writing has been made visible will
obviously be extremely fragile, but they may be rendered firm enough to
handle by applying a solution of collodion to the reverse side, which on
evaporation leaves a layer of nitro-cellulose similar to that with which
incandescent gas mantles are coated.
Any shrinkage or distortion of the letters in the writing caused by the
contraction of the ash of the paper during the incineration is obviated or
minimised by burning the carbonised paper very slowly.
A record of the revivified writing may also be made by means of
photography.
The one pound notes issued by the Bank of England until as late as 1826,
appear to have afforded peculiar temptations to forgery, judging by the
number of persons convicted of the offence.
[Illustration: A FORGED RECEIPT]
[Illustration: PORTION OF THE SAME
_By kind permission of "Knowledge"_]
[Illustration: TESTS TO DISTINGUISH OLD FROM NEW INKS
(SEE PAGE 110)]
The statistics on this point are very remarkable. Between the years 1797
and 1811, 471 people were convicted of uttering the notes or having them
in their possession.
In 1814, the number of fraudulent one pound notes detected was 10,342; in
1815, 14,085; in 1816, 21,860; in 1817, 21,241; and during the first three
months of 1818, 8,937.
The ease with which the notes could be imitated, and the readiness with
which they could be circulated, caused hundreds of people to take up the
trade of forgery, until at length whole days were occupied at the Old
Bailey with the endless trials and convictions.
Much indignation was expressed in the newspapers that the Bank had not
issued notes which could not be imitated, and as a result of this outcry,
a committee of scientific men was appointed to examine and report upon the
best means of checking the evil.
Their report stated that they had examined many specimens of engraving,
but none that had been submitted to them was proof against skilful
imitation. Most of the forged notes had been clumsily imitated, and from
this it appeared that the public were quite ready to be deceived by them.
It was commonly believed, though without foundation, that the Bank placed
a private mark upon their notes by which they could subsequently be
identified.
The general dissatisfaction with the behaviour of the Bank authorities was
intensified by the amount of public money that was spent in the
prosecution of the forgers, and the view was freely expressed that the
Bank had no right to assume the office of prosecutor.
In the year 1818, for instance, there were 242 prosecutions, the cost of
which was £34,357.
So pronounced became public opinion upon the subject that the Bank was
forced to allow the culprits to plead guilty to a minor charge, the
penalty for which was transportation instead of death.
This became almost a necessity, since there were frequently batches of
twenty or thirty convicted forgers awaiting execution, though the death
penalty was only exacted in a relatively small proportion of the cases.
During the seven years ending 1825 there were 78,918 males and 14,800
females tried on the charge of forging these notes. Of these prisoners,
17,874 were acquitted, while out of the remaining 75,844 sentence of death
was passed upon 7,770, though not more than 579 of these were executed.
Even this small proportion gave the terrible yearly average of
eighty-three executions.
As it was at that time impossible to stop these wholesale forgeries the
abolition of the issue of one pound notes, which took place in 1826, was
obviously the only solution of the difficulty.