CENSORS' SECRETS.

Taranaki Daily News, 24 September 1919, Page 10

CENSORS' SECRETS.

HOW SPIES WERE FOILED. [ THE INVISIBLE INK TRICK. The truth concerning the Postal Cen- | sors Department is more absorbing than fiction, and would liave moved even ' : Sherlock Holmes to admiration, remarks a London daily. This Department, which is now closed, iu}d its stuff demobilised, displayed on ingenuity which, rising to meet every occasion, foiled the spies of the craftiest enemy that ever waged war. Letters have yielded up all their secrets, even when written in the most abstruse codes o r in Swahili, Georgian, Basque, Neo-Syriac, Korean, Bantu, and even in Esperanto characters in Braille form. More than that, the Postal Censor has: — Mastered 142 languages. Read 375,517 letters a day, weighing four tons, and Provided a universal revealer in invisible, inks. WORK IN SECRECY. . Obviously, the public have heard very , little of this work during the war- The very essence of the Department was . secrecy, and the organisation had to bo improvised It had tp. learn its duties as it went along. Gradually these grew, until a stall' of 4080 was employed at a large building in Portugal-street-On the face of it the work might look simple enough. You open a letter and read (in German, or French, or Spanish, or Russian) the information that a liner will leave Cardiff on the evening tide on a certain date. All you have to do is to hand the letter over to the Admiralty and the Hun plot is foiled. But it is by no means as simple as this. The spy does not usually give himself away in that apparent manner. He may write an ordinary letter, sending his love to Uncle John, and hoping that father's gout is better, wivh the rem information written in invisible ink. -Or he may send his missive in shortnand—and there are dozens of Systems to choose from. Or he may choose some complicated cypher.code, and here again i lie field of choice is practically illimitable. TRACING THE SPY. Them are other dodges. One Harm-less-looking letter was written on the * back oi' n map of the City of Amsterdam. There was m>i. much in. this to excite suspicion; p.■per. had In en short enough, bill the lynx-eyed eenso: studied it, and saw that all the dotted tramway lines were carefully market out in. the' Morse code. The purport of that hidden message pu; tin' jaMlee on thtt track of a dangerous S|i\. Perhaps the most wonderful work of ail was done by Miss Adeney and Mr. Lloyd iu a top room. They spent, their time in tearing : 'i'' heart oi'il of the secret., oi ihe nu-'iibei'less cypher codes cmployed. The-,- showed volume after volume of cyphi. r letters carefully photographed and the cyphers worked out. The detective in fiction is generally j considered a master a( this game; he is a | mere infant when compared with these j two An apparently meaniti.aless jumble i of letters or figures-, alphabets made for I the.occasion, conceal.nothing from th.vu. Mr. Collins and his assistants dea'i ] with the letter., written in invisible ink, ' Ho showed how a letter written wit U \ milk can be made visible by merely rub- i bing a little graphite over it; or one ! on which lemon-juice has been used, with ! a warm flat-iron. And if nothing else can lie got, a letter written with a pen dipped in human saliva can be read quite easily if a brush dipped in blue ink is ]. assed over it. Thousands of letters had J,o be treated every day, so Mr. Collins set about discovering a universal, revealer—and he succeeded. The censoring of ordinary letters by no means exhausted the work done in Por-tugal-street. , At oiie time as much as six tons of enemy propaganda were sent to the pulping jnjjls every week,