212 



KNOWLlCDGi:. 



JiNi., 1912. 



Tlu'Sf facts supixiitrd tile cnnti'iilion of tlic other 

 side that tlic original loading liad hern " your." and 

 that thf " y " had boon erased. 



To lessen the chance of detection from such a 

 trail, skilful forgers have been known to paint the 

 jilace over with a resinous solution, so that super- 

 ficially it has the apjjearance of the rest of the 

 surface of the paper. This dodge may be detected 

 in- an examination of the sizing, the patched place 

 being easily stripped by brushing it over with alcoiiol. 

 in which the resin will dissolve. 



Tests have also been devised for distinguishing 

 between papers sized with material of animal and 

 of vegetal)le origin. For instance, if a small piece of 

 the paper be soaked in a two |)er cent, solution of 

 copper sulphate, and then treated with a few drops 

 of a five per cent, solution of potassium hydroxide, 

 a violet coloration (the biuret reaction) is at once 

 obtained if gelatin or casein is present. 



In certain cases " Hughes' iodine reaction " mav 

 also aid in the differentiation of two kinds of paper. 

 If a strip of paper is moistened with potassium 

 iodide solution and suspended in a place protected 

 from chemical fumes, a gradual liberation of iodine 

 will take place. This appears to be due to the 

 presence of undecomposed alum or aluminium 

 sulphate in the paper, and according to Strachan 

 {Cheiii. W'lcs, 1911, cm, 193), the intensity of the 

 coloration affords a measure of the latent acidity 

 (due to the alum) in the paper. It also gives a 

 probable explanation of the rapid deterioration of 

 certain modern written documents. 



Commercial papers differ considerabK- in their 

 helia\'iour in this test, and upon its results ma\' be 



Figure 235. 

 Fibres from Eighteenth Ceiituiy Paper. 



based an approximate estimation of tlie amount of 

 undecomposed alum present. 



In addition to the ink, the paper, and the writing 

 itself, there are frequentK' other points about a 

 questioned document wiiich will repay careful 



examination ; for the pitf.ills are so numerous that 

 in avoiding one a forger will almost certainly fall 

 intf) another. 



In illustration of this the following amusing case 

 within the writer's experience may be cited : — .'\ 

 [ewish family insured their household goods and, in 



l-'i<,ri<i: J.iii. 

 Fibres from Modern " M.inilla " Writing l'.Hper. 



particular, a iiiianlitN' of valuable jewellery, with one 

 of the leatling insurance companies in London. 

 I>eing thus protected, the\- soon became the pre\' of 

 enteri)rising burglars, and in this unfortunate affair 

 lost all their jeweller\-. which was valued at about 

 £150. 



In the claim presented to the company receipts 

 were produced signed by the jeweller from whom, as 

 they alleged, they had bought the jewellery. 



Such claims, when not genuine, are not eas\- to 

 disprove, although in the present case the insurance 

 companv had a strong suspicion that there had been 

 no burglarw but that bogus receipts had been 

 concocted in collusion with the jeweller, who had an 

 address but no shop. 



There were in all three receipts, the first made out 

 in December to the eldest daughter, the second in 

 January to the father, and the third, which was 

 dated in Februar\-, to the daughter, who had been 

 married since the ciate on the first receipt. 



The paper of the bill-heads of the first and third 

 receipts was of the same kind, and the writing on 

 these was in the same sort of ink, whereas the paper 

 and ink of the second receipt were of a different 

 kind. 



The inks upon the first and third bills were of 

 too recent origin to determine whether they were 

 of the same age. although it was significant that 

 thc\ beha\ed in exactly the same way towards 

 bleaching reagents. 



