
This is a 12-bar blues that modulates from the key of G to C. Rev. Davis showed Ernie this back in the sixties. As this is the only version Ernie has ever heard, he doesn't know if Rev. Davis was improvising around the song or playing it as a relatively set piece like Slow Drag.
In the C part, the 12th bar has a Ab7 instead of G. For the G part, the melody starts on the open 3rd string (the I) and walks up, in the manner of Blind Blake, to the minor 3rd, then the 3rd, then to the fifth. It does exactly the same thing with the C chord. It then moves up to the D form G, and down to the E form. In the C part he used the minor to major, 4th fret second string to 1st string open beautifully. As he played that melody, he was able to harmonize a counterpoint middle line on the same frets of the G and D strings. He taught us all how to do this with Fast Fox Trot.
This is an example of the Rev. arranging a recording from a band for solo Piedmont guitar. He was a master at this. His guitar not only imitated a piano but brilliantly and effortlessly, it seemed, reproduced the sounds of a whole band.