Buell's Mercantile Cypher (1860) appears on eve of the Civil War and near the end of the canal transport for which it provides language. Code compilation was still tentative at this time; its phraseology is practical but too specific and even politely long-winded, giving it the tone of an exercise book. The nature of the markings throughout the present copy suggest that it was used for preparation for another code, based on and incorporating some, and rejecting much else, of its content.