paper any more. It looks like foreign writing paper, very thin and glazed. I can write anything I choose on this letter now. When they get the letter and develop it the writing appears positively black. I head the letter 'Dear Bob' and they know it is a code letter. When I am through with the letter I use the word 'Schluss,' because in developing it, they want to know if they have the entire letter, and that word ends it up."
This passenger also told the examining officials that in carrying addresses without an address book, the German agents usually take a bone button of an overcoat or a large button of some sort and on the reverse side scratch the address with a diamond, sometimes also scratching instructions which they cannot carry in their heads. After this they treat the button with shellac, or, as they call it in Germany, "spitituslak." That fills the crevices and dries rapidly. On reaching the destination, they use pure alcohol to wash off the shellac. They also write addresses on this paper and work them into leather buttons.
Cipher and code are part of the education of certain
intelligence officers, but into a discussion of these matters
we may not go, as they are secrets of the American Government.
Our own experts were able to decipher and
decode all the secret messages bearing on the great German
plots in this country, but this was not usually A. P. L.
work. Of course, the lay reader, or more especially the
A. P. L. member, may know that a cipher means the substitution
of some symbol, or some number, or another
letter, for each letter of the alphabet. Or the real letters
may be transposed, one to stand for another, in such a way
that only the sender and receiver may understand. That
looks hard to read? Not at all. It is easier than code.
It is said that any cipher message can be unriddled in
time.
A code is a scheme agreed on by which the two parties substitute certain whole words for the real words of the message. A code message might seem wholly innocent—let us say, just a simple comment on the weather. But suppose "bright and fair" meant in code "The Leviathan sailed this morning," and suppose the Leviathan were a transport carrying twelve thousand troops to France! Unless the de-code artist is indeed an artist, he cannot
