This is a cipher in which the words or a message are retained unchanged, but are so disarranged by preconcerted rules that the sense becomes unintelligible. The message as received seems to be a number of disconnected words and without meaning, but by arrangement in proper order in accordance with certain rules can be easily read. Messages enciphered in this manner may be translated by persons not in possession of the key, and therefore the information contained therein should only be of such a character as to be of little value to the enemy unless acted upon immediately. The usual method employed in arranging a message for this cipher is to write the words in vertical columns. The number of words in each column should always equal the number of columns, being made so, if necessary, by the addition of sufficient "blind" words. A preconcerted route is agreed upon, as up to the first column, down the third, up the second, etc. The message is then transmitted without reference to the columns, but is deciphered at the receiving station by column arrangement and perusal along the original route. For example, to encipher the message "Move daylight. Enemy approaching from north. Prisoners say strength one hundred thousand. Meet him as planned," arrange as follows: Move strength planned say daylight one as prisoners enemy hundred him north approaching thousand meet from Here the route is down the first column, up the fourth, down the second, and up the third. CIPHER DETECTION. _General instructions._--In deciphering a message in which the same cipher letter or symbol is uniformly used to represent the same text letter, the following data will be of assistance. The proportion of occurrence of letters of the alphabet in English words is as follows: For every 2 of the letter Q there are 4 of the letter X, 8 of K, 16 of B, 13 of C, 80 of I, N, O, and S; 85 of A, 90 of T, and 120 of letter E. The compounds most frequently met with are NG EE LL MM TT DD and NN. The order of frequency in which the letters of the alphabet occur as initial letters in words is as follows: S, C, P, A, D, I, F, B, L, T. _Employment of Cipher Disk._ If messages are enciphered by a mere transposition of the letters of the alphabet, the cipher disk can be used to quickly decipher the message, as the following example will show: Assuming that F is used to represent A, G to represent B, H to represent C, I to represent D, J to represent E, etc., in regular sequence, and that the message to be enciphered is: "We are short of rifle ammunition; send 30,000 rounds at once." This would be enciphered if divided into groups of four letters as follows: jbfo bnyr omra oxub fuls xmxr snbs cmjb smhm yrln fsco rlsc nfmr sdb.