forty centuries of ink-第29章
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as 〃carmine〃）； madder； Brazil wood and saffron formed
the basis of most of the red inks。
Make a soap solution adding a small quantity of
ammonia； lemon juice； muriate of tin； all in water：
1。 No change upon application indicates madder。
2。 Any change； the presence of one of the three other
reds： （a） thus a complete decoloration with a return
of the color indicates saffron； （b） reappearance of the
red color though weaker； aniline…red： （c） production
of a yellowish red or light yellow color； cochineal or
Brazil wood； to be distinguished from each other by
the application of concentrated sulphuric acid； when
Brazil wood will at once give a bright cherry…red； and
cochineal a yellowish orange。
No yellow inks are in commercial use。 Documents
do； however； often contain yellow marks about which
information is required as to their origin。 As a rule
they are iron rust； picric acid； turmeric； fustic； weld；
Persian berries or quercitron。 In order to recognize
the different colors； the presence or absence of iron
rust and picric acid must first be determined。
Apply a warm sample of a slightly acid solution of
yellow prussiate of potash； iron rust will be indicated
by a blue coloration。
Apply a weak solution of cyanide of potassium； picric
acid will yield a blood…red coloration。
If picric acid and iron rust are both absent； apply a
bit of ordinary wetted soap： 1。 It turns reddish…brown
and becomes yellow again with hydrochloric acid
turmeric； 2。 It turns quite darkfustic； 3。 It is
unaffectedweld； Persian berries or quercitron。 To
distinguish between these three； apply sulphuric acid；
the color of weld will disappear； and of the others
remaining apply tin…salt solution； when a change to
orange indicates Persian berries； and no change or a
very slight one； quercitron。
Inks containing also logwood； fustic； Brazil wood；
or madder； were all of them more or less employed
some years ago。 Their color phenomena； following
long periods of time； is much the same。 Tests as prescribed
in the accompanying table for such inks will
serve to classify them preliminary to subsequent and
more certain ones。
LOGWOOD。 FUSTIC。
Concentrated Hydrochloric Acid Red…yellow Red
Dilute 〃 〃 Reddish Yellow…Brown
Concentrated and dilute Nitric Acid Red Red…Yellow
〃 Sulphuric Acid 。 。 Black Dark Purple
Dilute 〃 〃 Red Brown Purple
Potassium Chromate 。 。 。 。 Black
Stannous Chloride Violet Yellow
Tartaric Acid 。 。 。 。 。 Gray…Brown Yellow
Sulphate of Copper 。 。 。 。 Dark Gray
Tannin 。 。 。 。 。 。 Yellow…Red Yellow
Potash Dark Red Yellow
Potassium Permanganate Light…Brown Yellow
〃 Iodide 。 。 。 。 。 Red…Yellow
Pyrogallic Acid 。 。 。 。 Yellow…Brown Yellow
Chrome…yellow 。 。 。 。 。 Dark Violet
Sodium （Salt） Violet Red
Sulphate of Iron Gray to Black
Alum 。 。 。 。 。 。 。 Violet Red；Brown。 Faint Red
BRAZIL WOOD。 MADDER。
Concentrated Hydrochloric Acid Light Red Pale Yellow
Dilute 〃 〃 Light Red Pale Yellow
Concentrated and dilute Nitric Acid Dark Purple Pale Yellow
〃 Sulphuric Acid 。 。 Red Pale Yellow
Dilute 〃 〃 Purple Pale Yellow
Potassium Chromate 。 。 。 。 … …
Stannous Chloride Light Red Light Red
Tartaric Acid 。 。 。 。 。 Red Yellow Pale Yellow
Sulphate of Copper 。 。 。 。 … …
Tannin 。 。 。 。 。 。 No Change Pale Yellow
Potash Crimson Light Red
Potassium Permanganate … …
Iodide 。 。 。 。 。 … …
Pyrogallic Acid 。 。 。 。 … …
Chrome…yellow 。 。 。 。 。 … …
Sodium （Salt） … Red
Sulphate of Iron Dark Violet …
Alum 。 。 。 。 。 。 。 … Faint Red
CHAPTER XIX。
FRAUDULENT INK BACK GROUNDS。
DETECTION OF ALTERATIONS IN DOCUMENTS BY CHEMICAL
TESTS WHICH APPLY SOLELY TO THE PAPERACCURACY
OF RESULTS OBTAINED BY USE OF IODINE
EXCELS THAT OF ALL OTHER CHEMICALSIT APPLIES
BEST TO LINEN PAPERMODERN HARD PAPER DOES
NOT GIVE COMPLETE INFORMATIONEFFECT OF IODINE
ON MARKS MADE BY A STYLUS OR GLASS PEN。
FIFTY years ago and long before the employment of
the fugitive 〃anilines〃 for ink uses； and 〃wood
pulp〃 as a material for paper； two French chemists；
Chevallier and Lassiagne； published in the Journal de
Chimie Medical； an article 〃On the Means to be
Employed for Detecting and Rendering Perceptible
Fraudulent Alterations in Public and Private Documents；〃
which as translated is valuable enough to
quote in full：
〃The numerous experiments which have been
already tried at various times； have made known
the processes which may frequently be put in practice
for causing the reappearance of traces of writing
effaced by chemical reactions； and for throwing
light on the work of the guilty。 But there are
cases in which all the means proposed for this purpose
fail； and then the criminal may escape justice
from the want of conclusive material proofs。 If；
as has already been proved； it is not always possible
to cause the reappearance of the effaced writing；
for which written words have with a fraudulent
intent been substituted； at least； as our
experiments demonstrates； we may recognize； by
some effects which are manifest on the surface of
the altered paper； the places where the criminal act
has been performed； circumscribe them by a simple
chemical reaction visible to the least practiced eye；
and even measure their extent。 In a word； the
visible alterations produced on a deed are susceptible；
owing to the partial modifications which the
surface of the paper has undergone； of being differently
affected by certain chemical actions； and
of being rendered visible。 The following experiments；
made in a judicial investigation； furnish us
with the following facts：
〃1st。 The surface of paper sized in the ordinary
way； or letter paper； no longer presents with certain
reactions； the same uniformity where it has
been either accidently moistened in several places
by various liquids； or left in contact for a certain
time with agents capable of removing or destroying
the characters which have been traced on it with
ink。
〃2d。 The application of a thin layer of gum； of
starch； or farina； of gelatine； or fish…glue； with a
view of sizing certain parts of the paper； or of
causing certain bodies to adhere to it momentarily；
is detected by an action similar to that which
shows paper to have lately been wetted by the contact
of liquids。
〃3d。 The heterogeneousness of the pulp of the
papers； and the kind of size with which they are
impregnated； lead to differences in the results
which are observed with the same chemical reagents。
We shall now examine each of these propositions；
and describe the means which we have
employed in endeavoring to solve questions of so
high a degree of interest。
〃1st。 The homogeneousness of sized paper not
partially altered by the contact of liquids （water；
alcohol； salt…water； vinegar； saliva； tears； urine；
acid salts； and alkaline salts） is demonstrated by
the uniform coloration which this surface takes on
being exposed； if not wholly； at least in various
parts； to the action of the vapor of iodine disengaged
at the ordinary temperature from a flask
containing a portion of the metalloid。 When the
surface of paper not stained by any of the above
mentioned liquids is exposed to the action of this
vapor for three or four minutes in a room the temperature
of which is about 60 degrees F。； a uniform yellowish；
or light…brownish yellow； coloration is noticed
on the whole extent exposed to the vapor of
iodine； in the contrary case； the surface which has
been moistened； and afterwards dried in the open
air； is perfectly distinguished by a different and
well circumscribed tint。 On the papers into which
paste starch and resin have been introduced； the
stains present such delicate reactions that we may
sometimes distinguish by their color the portion of
paper which has been moistened with alcohol from
that which has been moistened with water。 The
stain produced by alcohol takes a bistre…yellow
tint； that formed by water is colored of a more or
less deep violet blue； the desiccation having been
effected at the ordinary temperature。 For the
stains occasioned on these same papers by other
aqueous liquids； the tint； apart from its intensity；
resembles that of the stains of pure water。 The
feeble or dilute acids act like water on the surface
of the same paper containing starch in its paste；
but the concentrated mineral acids； by altering
more or less the substances which enter into the
composition of the latter； give test to the stains
which present differences。 We are always able
to recognize by the action of the vapor of iodine
the parts of the paper which have been put in
contact with chemical agents； the energy of which
has been arrested by washing in cold water。 We
are able； on several ancient deeds； written on
stamped paper； and a few words of which had
been removed by us with chemical agents； to
recognize the places where their action was exerted；
to see and to measure the extent which they occupied
on the surface of the paper。
〃The testing of a paper with the vapor of
iodine will present this double advantage over the
methods hitherto practiced for detecting falsifications
in writings； that it points out at once the
place in the paper in which any alteration may be
suspected； and that； on the other hand； it enables
us to act afterwards with the reagents proper for
causing the reappearance of the traces of ink； when
that is possible。 If the means which we now propose
cannot always make the former writing
appear； they demonstrate the places where the
alterations must have been made； when； however；
the want of uniformity presented by the surface
of the paper is not explained by any circumstance。
This proof becomes； therefore； a weapon which
the guilty person cannot avoid。 But might not
the presence of a stain； or several stains； developed
by the vapor of iodine； in different parts of a public
or private deed； give rise to a suspicion； where
these stains hav
