What is the coding of this spiritual?When the Sun comes back And the first quail callsFollow the Drinking Gourd,For the old man is a-waiting for...

There is a debate about the song "Follow the Drinking Gourd" and the possiblity that it contains a coded message. Let me answer your question first and then go on to briefly outline the controversy and list some sources that you might wish to consult.

According to a number of sources, the song's lyrics provide a coded set of instructions for escaping slaves. For example, lines 1-2 of the lyrics supposedly mean "in springtime" (when the days grow longer and birds become more active), and lines 3-4 supposedly mean "use the Big Dipper and maybe a human guide as you travel northward to freedom" (the Big Dipper can be used as a pointer to locate the North Star). The NASA Quest page listed at the end of this answer gives a full explanation of this supposed code in the lyrics.

I've used the words "supposed" and "supposedly" over and over again here because I think that it's important to realize that this claim of a code in the song's lyrics is controversial. The oldest recognized source for this claim is a 1920 essay by H.B. Parks in a Texas folklore journal. I suspect that few people have read the original (and not entirely convincing, to my mind) essay and are more likely to know the story through Jeanette Winter's 1988 children's book, Gloria Rall's 1995 planetarium show guide, or various web sites.

Recent research by Joel Bresler and James Kelley (see the final two references given below) challenges the claim of a coded message. These researchers take very different approaches, but both arrive at the same conclusion: there is little to no evidence supporting the claim that slaves actually used this song to escape northward and to freedom.

Rather than simply dismiss the claim of a coded message in the song lyrics as meaningless because the claim does not seem to be historically "real," however, we might begin to ask ourselves why many of us find this claim appealing. Does it appeal to our desire for justice, for example, or our tendency to cheer for the underdog?

In any event, you've certainly asked an interesting question.

--

Note: Tne reference to James Kelley's print article didn't show up at the end, so I'm adding it here:

Kelley, James. "Song, Story, or History: Resisting Claims of a Coded Message in the African American Spiritual ‘Follow the Drinking Gourd’”. The Journal of Popular American Culture 41.2 (April 2008): 262-80.