SCIENCE TRAPS FORGERS

Evening Star, Issue 23382, 27 September 1939, Page 14

SCIENCE TRAPS FORGERS

KEEN EYE OF THE "BLACK RAY" REVEALS GLUES FOR DETECTIVES Forgers of baulk notes are among tbe most expert of criminals. Indeed, they have to be, for they are trying their skill against scientific investigators armed with every kind of technical device to defeat them. Yet even today note forgery gives the police more trouble than almost any other kind of crime. The forger may manufacture thousands of pounds worth of forged money and remain undetected for several years. Ten years of immunity is not unknown. In this respect forgery is much more dangerous than any other crime. Forgers work in many different ways. A skilled draughtsman with Indian ink, suitable pens and paper, can produce five-pound notdk which will escape detection except by an expert of the Bank of England. UNDER THE MICROSCOPE, A case of this kind occurred three years ago. These pen and inlk drawn notes were beautiful imitations of the genuine article. But modern laboratories have extremely efficient methods of dealing with forged notes. To begin with, there is a particular type of microscope known as the comparison microscope. It shows highly magnified pictures of suspect and genuine notes or documents side by side. This instrument is the most powerful enemy of the forger, for it i reveals minute faults which the eye cannot see and combines this magnified picture with one of the genuine article. Next there is what is known sometimes as the “ black ray.” This term is not quite correct, because the ray, which is filtered ultra-violet light, is not entirely invisible; it has a curious faint blue colour. But when it falls upon different materials, it makes them glow, or fluoresce. The fluorescence is different for different kinds of paper. The ultra-violet ray infallibly distinguishes between the false and the genuine banknote. No forger has ever been able to match the paper from which genuine notes are made. A counterfeiter once managed to steal a quantity of paper from the mills where it was made, but he could not secure the completely finished product. He might otherwise have been able to produce the almost perfect forgery. The use of ultra-violet rays for the examination of counterfeit moneys is one of the greatest discoveries of the century in connection with the detection of crime. Tracing the forged notes is one part of the problem j the other is running

the actual forger down. The detective in the laboratory can often - help herd. For example, a colleague of the writer discovered by the microscopical examination of some false notes r which ’ had been drawn free-hand that they were the work of two different people. INK TRACED, He also made a micro-chemical examination of the ink. The ink was found to correspond with some found in the house of two brothers. On this evidence and that of other damaging facts which came to light they were arrested and finally convicted. Chemists can also make exact analyses of paper as they can of most other things in these days. This fact has proved disastrous to many note forgers. If, for instance, the chemist finds' that paper of a certain composition has been used to produce counterfeit notes, and later the police discover quantities of paper in suspicious circumstances, they submit it to the laboratory. If the composition is found, to be the same, the owner of the paper is rather naturally asked if he would care to make a statement. Nothing is perfect, not even a Bank of England'note, and the very fact that note printing is not perfect is often very useful in the detection of forgery. A most remarkable example was one in which certain suspect notes of foreign origin were clearly proved to be forged because they were better printed than tlm genuine money! ; This never occurs in England, or in any of tbo large European countries, because the standard of official printing is very high, but the case quoted is by no meana unique.