Now you will remember those percentages of vowels and consonants. Here is where they come in. When a message is picked up the army expert counts the times that the vowels recur, and if they do not check with the 40 per cent for the common vowels, with the consonant figures tallying within 5 per cent of the key, he knows that he is up against a substitution cipher. The transposition kind will check to a gnat’s heel. When the expert knows exactly what he is up against he is ready to apply the figures and patiently unravel the story. It may take him hours, and maybe days, but sooner or later he will get it to a certainty. If he has picked up a transposition fellow he proceeds to examine it geometrically, placing the letters so that they form all sorts of squares and rectangles that come under the heads of simple horizontals, simple verticals, alternate horizontals, alternate verticals, simple diagonals, alternate diagonals, spirals reading clockwise, and spirals reading counter-clockwise. Once one gets the arrangement of the letters, the reading is simple. For instance, ILVGIOIAEITSRNMANHMNG comes along the wire. It doesn’t figure for a substitution cipher and you try the transposition plan. There are twenty-one letters in it, and the number at once suggests seven columns of three letters each. Try it on your piano: I L V G I O I A E I T S R N M A N H M N G And reading down each column in succession you get “I am leaving this morning.” After passing over several simple ciphers as not “classy” enough to engage the reader’s attention, the writer takes up one of a much more complicated nature, which, however, did not get by Uncle Sam’s code wizards. Follow the deciphering of this example by Captain Hitt: He began with an advertisement which appeared in a London newspaper, which read as follows: “M. B. Will deposit £27 14_s._ 5_d._ to-morrow.” The next day this advertisement in cipher appeared: “M. B. CT OSB UHGI TP IPEWF H CEWIL NSTTLE FJNVX XTYLS FWKKHI BJLSI SQ VOI BKSM XMKUL SK NVPONPN GSW OL IEAG NPSI HYJISFZ CYY NPUXQG TPRJA VXMXI AP EHVPPR TH WPPNEL. UVZUA MMYVSF KNTS ZSZ UAJPQ DLMMJXL JR RA PORTELOGJ CSULTWNI XMKUHW XGLN ELCPOWY OL. ULJTL BVJ TLBWTPZ XLD K ZISZNK OSY DL RYJUAJSSGK. TLFNS UVD W FQGCYL FJHVSI YJL NEXV PO WTOL PYYYHSH GQBOH AGZTIQ EYFAX YPMP SQA CI XEYVXNPPAII UV TLFTWMC FU WBWXGUHIWU. AIIWG HSI YJVTI BJV XMQN SFX DQB LRTY TZ QTXLNISVZ. GIFT AII UQSJGJ OHZ XFOWFV BXAI CTWY DSWTLTTTPKFRHG IVX QCAFV TP DIIS JBF ESF JSC MCCF HNGK ESBP DJPQ NLU CTW ROSB CSM.” Now just off-hand, the average man would shy away from this combination as a bit of news that he really did not care to read. But to the cipher fiend it was a thing of joy, and it illustrates one of the many cases that they are called upon to read, and the methods by which they work.