The Cab of the Sleeping Horse

by John Reed Scott

Assume that the message to be transmitted is: “To-morrow sure,” and that the key-word is: “In the inn.” Write the key-word and under it the message:

INTHEINNINTH

TOMORROWSURE

Then trace downward the I column of the top line of the square, and horizontally the T column at the side of the square until the two lines coincide in the letter B: the first letter of the cipher message. The N and the O yield B; the T and the M yield F; the H and the O yield V, and so on, until the completed message is:

BBFVVZBJAHKL

The translator of the cipher message simply reverses this proceeding. He knows the key-word, and he writes it above the cipher message:

INTHEINNINTH

BBFVVZBJAHKL

He traces the I column until B is reached; the first letter in that line, T, is the first letter of the message—and so on.

Simple! Yes, childishly simple with the key-word; and the key-word can be carried in one’s mind. Without the key-word, translation is impossible.