A month or two ago I read the historical novel "From Sea to Shining Sea" which narrates the history of the Clark family - George Rogers Clark of Revolutionary War and Kentucky fame and William Clark of the Lewis and Clark expidition being perhaps the most prominent members of that generation. In one episode George tells William, as the latter is preparing for the Expidition, the secret of keeping the men loyal to the leadership. Among the advice was to always have a joke, a song, or a dance to cheer them up. There are several snippets of song lyrics in the book also.