Science and the Criminal

e of Inks-Carbon Inks-Herculaneum

ethods of distinguishing between different kinds of ink in handw

copperas, or as it is now termed, ferrous sulphate. These substances combine with one another to form a tannate of iron, which gr

nt in colour when first applied to the paper, and it is only after the air

ere boiled in order that the insoluble black pigment might form within the liquid, and thus give some colour to the ink when it was first put u

partial oxidation is not employed, but a colouring matter is added instead, so that the writing has

use the same substance for this purpose. In some inks indigo is employed, in others logwood, while the introd

en writings done with different kinds where some mistake had been made in the

tood when it is remembered that ink-making was formerly as much a part of t

e the ink-manufacturer could not have existed, for there would have been no custom

assortment of items directions for making everything needed for the household, from apple pasties to cures for the king's evil. This particular recipe, which was one of several for making ink, was probably written towards the close of the sixteenth century. It gives directions for soaking the galls in rain w

domestic r

f, and it is to this cause that we must attribute the want of permanency of the ink in som

useum. It will be noticed that all the entries of the births of himself and the members of his family are in the handwriting of Milton, and that with one exception all the inks are of a good dark tone. The exc

blackness of the pigment, but a deficiency of tannin outside those limits will cause the writing to turn brown. A lack

ten entries would have shown that the ink in this entry was of d

more accurately than is possible with the naked eye, has been used in matching the colour obtained

orm a series of colour scales are employed in this instrum

Tint

ork was in the Brinkley poisoning case, in which the colours of the diff

is much more difficult than that of deciding whether two

p to about the sixth day, after which the black pigment has attained sufficient intensity to prevent further differentiation until

he iron tannate when exposed to the action of light and air, and eloquent testimony to this difference is given by the comparison of c

will gradually fade out, leaving the black pigment; and when this stage is reached the i

r appears to become enveloped in the particles of iron tanna

d there is an immediate diffusion of the blue pigment, whereas in the older

smudge, but has very little, if any, effect on writing six or eight years old. The differences in the behaviour of old and relatively recent writing are seen

me kind of ink and the tests

usion occurs in an older ink it is seen under the microscope to differ in character and only to affect the surface of the lett

d of forging his cousin's will. This will was alleged to have been written in 1898; and assuming this to have been the case, the ink should only have reacted very slowly with the

at once with oxalic acid, and the diffusion extended throughout the whole of the letters. There was thus no doub

ts, and while those written quite recently gave an immediate diffusion, the ink upon those written in 1903 showed only

mple matter to distinguish between old and new writing, for it is easy to differe

ertain claimants of old-age pensions, who, as a proof of their age, ha

ation of the inks have failed to support the claim, for they

inks. For the basis of all these ancient inks is lampblack, or some other form of carbon, which is very resistant to the action of reagents. It is for this reason that printing ink, the pigment of which is

al Indian or Chinese ink, which consists essentially of a mixtur

agent. The blue-black pigment of the writing ink will then gradually disappear, whereas the fine particles of carbon in the other ink will

um, which was destroyed in A.D. 79, had been done with a carbon ink, of the same nature as that used by the ancient Egyptians

ther the writing upon a document has been lith

have been written by Nelson had been handed down in a family for several generations as an heirloom, and had always been looked upon as a genui

t in his possession, and when a chemical test was applied to the ink upon the latter the pigment was quite

ons. As a recent example a case that was tried a few months ago may be mentioned. The chief clerk of a firm of merchants had for a considerable time been defr

obtained a mixture, which gave an immediate effect of age to the writing. To the naked eye there was nothing to show that these pages had not been written on the dates mentioned on them, three or four years previously, but on applying a weak bleaching agent the fraud was at once made obvious. The iron-gall

at beset the forger of ancient documents was affor

date back to the seventeenth and early eighteenth centuries. One of these purported to be a portion of a charter granted by King Ch

matter of history the seal had been handed to the Marquis of Hamilton a year prior to the date of the pretended charter.

the pretended charter was not old ink, but ink that

scientific proof was given that the date upon an engraved map, upon the back of wh

y found the prisone