To code a message such as “meet me at noon,” the letter m is located on the wheel at the left end of the instrument; the next wheel is turned until the letter e is adjacent to the m; the third wheel is turned until the second e is next to the first e; and so on, until all words in the message are spelled out in up to 12 letters with no spaces between them. Each of the remaining rows of letters on the cylinder represents a different encryption of the message. To send the cypher, the sender copies the sequence of letters in any one row. The recipient arranges the letters on any row of his cylinder into the sequence received, and then rotates the whole cylinder until he recognizes a meaningful series of words.