DISCOVERY 



319 



It is owing to the use of different pigments for this 

 provisional colouring matter that it is often possible 

 to distinguish between the inks of different manu- 

 factures in \vriting. B3' treating the writing with 

 dilute acid the iron tannate may be bleached, leaving 

 the aniline dye available for examination. Whether or 

 not provisional colouring matter of an ink is an aniline 

 dye may be of importance. During the last years, 

 entries in famUy Bibles have been produced in support 

 of claims to a pension, but the presence of an aniline 

 dye in the ink, on more than one occasion, has proved 

 conclusively that the entries were forgeries. 



The different proportions of iron and tannin from 

 various sources also contribute to the character of the 

 reaction given in ink by writing. An expert, after a 

 series of systematic tests with his reagents, and using 

 an apparatus called a tintometer to compare the 

 changes in colour of the ink produced by the reagents, 

 can frequently tell one kind of a blue-black ink from 

 another with certainty. The first occasion on which 

 the method was used in an English Court of Law was 

 at the trial of Brinkley in 1907, when it was proved 

 that an alleged will was written in three different 

 kinds of ink. 



Judging the approximate age of an ink is generally 

 much more difficult than deciding the identity of two 

 inks. There are certain distinct differences in the 

 microscopical appearance of very old and of modern 

 inks. The latter show a much more crystalline 

 appearance, mainly due to the pigment attached to 

 the fibres of the paper, and it is often possible to see 

 dark margins to the lines due to the greater absorption 

 of pigment at the places where the pressure of the 

 divided pen nib was applied. This is illustrated in 

 Figs. I and 2. 



It was mentioned above, when the properties of an 

 iron-gall ink were being described, that comparatively 

 new inks are smudged when treated with certain 

 reagents, while older ones either do not smudge or are 

 affected only very slowly. This method of deciding 

 the age of the ink on a document was used by the 

 writer in the case of Rex v. Pilcher which was tried 

 in 1910. It was found that the ink in the body of 

 a will, alleged to be eleven years old, and of all 

 the signatures, reacted immediately with several 

 reagents and gave a copious smudging of the blue 

 pigment, while all indications of the black pigment 

 at once disappeared. Its characteristics therefore 

 did not agree with those to be expected of an ink 

 eleven years old. When similar tests were applied 

 to inks upon a series of cheques w'ritten by the lady 

 who was alleged to have signed the w'Ul, a fairly 

 rapid reaction and smudging was found on cheques 

 two or three years old ; much less reaction and 

 smudging on cheques five years old ; little reaction 



and almost no smudging on cheques six years or 

 more old, and no effect at all for a long time on 

 cheques as old as the will was said to be. It was 

 deduced from this that the ink, and therefore the 

 will, could hardly ha\-e been six years old. More- 

 over, the ink of the cheques was the same kind of 

 blue-black ink as that on the will, so that the compari- 

 son of their behaviour to reagents was a fair one. 



In Fig. 3 the behaviour of writing of 1909 in the 

 presence of dilute acid is compared with that of 

 writing of 1921. 



Of course common sense is sometimes a sufficient 

 guide in deciding the authenticity of handwriting. 

 An ancient ink, for example, cannot be genuine if it 

 contains an aniline dye. An interesting case may be 

 quoted from Mr. Lucas's book on Forensic Chemistry. 

 A register was presented in Court in support of a case. 

 The dates of the entries extended over more than a 

 year, and it was stated that the register had been kept 

 and entered up in an office. The book, however, was 

 clean and new-looking, and quite free from dirt and 

 dust, the ink was a bluish-green aniline ink, and so 

 could not be dated from chemical evidence, but it was 

 of exactly the same colour throughout, and the writing 

 was in the same hand and was aU done with the same 

 or a similar pen, but showed signs of haste or fatigue 

 towards the end. In two instances an entry which 

 belonged to several lines below had been made and 

 afterwards erased, and the dots under a word to 

 indicate repetition, which occurred plentifully on every 

 page, had in some instances been written vertically 

 on a number of different lines at the same time, the 



1 10. 3.— EFFECT OF A RE.^GENT o.N blA E-bLACK IRoN-GALl. 

 INKS OF THE SA>IE TYPE IX WRITING OF 1909 AND 192 1. 



ink showing progressivelv diminishing intensity of 

 colour from the top to the bottom of the page. It is 

 needless to add that the register's genuineness was not 



established. 



REFERENCES 

 Forensic Chemistry. By A. Lucas. (Arnold, i6>.) 

 Inks : their Composition and Manufacture. 2nd Edition. By 



C. Ainsworth Mitchell and T. C. Hepworth. (Griiifin, 9s.) 

 Documents and their Scientific Examination. By C. Ainsworth 



Mitchell. (Griffin, los. (>d.) 



(An article by the same author on Pencil Pigments 

 in Writing will appear in the January number.) 



