The song of the week is 'Fireball Mail' in the key of G.
Flatt & Scruggs - key of G, instrumental. The classic bluegrass version
Roy Acuff - key of A, the original sung version. Country/pre-Bluegrass
Earl Scruggs again - key of G (this time with his sons - not exactly a traditional bluegrass band, but good guitar and fiddle breaks here, plus a harmony back-up part played on the banjo behind the fiddle break)
Although Fireball Mail - originally a Roy Acuff song - does have lyrics (verses, no chorus), it was recorded by Flatt and Scruggs, on the Foggy Mountain Banjo album, as an instrumental featuring banjo and dobro; and it is through this recording more than any other that Fireball Mail has become a standard in the bluegrass repertoire.
Although I will lead Fireball Mail at the jam as an instrumental, I have included the lyrics for the first verse in the melody sheets, since some people find it easier to learn and/or remember a melody when they can associate a set of lyrics with it.
The chord progression used for 'Fireball Mail' on the Flatt & Scruggs recording is the standard progression for the song when played at bluegrass jams:
This is the same progression that is used to play 'Canaan's Land', 'Gathering Flowers From The Hillside', the verses of 'Feast Here Tonight', and (at our jam) the verses of 'I'm Gonna Sleep With One Eye Open')
However, unlike the four songs just mentioned, there is nothing in the melody of 'Fireball Mail' that requires changes from the 1 to the 5 chord. On the 7th, 8th, and 14th measures of Fireball Mail, the main melody note is the 5th note of the major scale (D note when in the key of G). This note is common to both the 1 (G) and the 5 (D) chord: G=GBD; D=DF#A. Furthermore, in playing his breaks, Scruggs completely ignores the changes to the 5 chord, choosing to play G and B notes around the D melody notes in the '5 chord' measures, rather than F# and A notes. This is especially noticeable in his up the neck break.
Although the melody only consists of 8 notes, the range of the melody spans almost one and a half octaves. This is an exceptionally wide range for a tune that was originally written as a vocal number. (Fireball Mail has the same range as another recent song of the week: 'Down In A Willow Garden', but unlike 'Down In A Willow Garden', the lowest note and the highest note in the melody are dwelt on rather than used merely in passing).
The melody notes for Fireball Mail, in ascending order of pitch, are (in the key of G): D,E,G,A,B,D,E,G (same as 'Down In A Willow Garden, when played in G). This means lots of open strings and 2nd fret notes on banjo and dobro, and lots of opportunities for unison slides/hammer-ons. Additionally, many of the G and D notes in the melody are held for a long time (a whole measure or longer) before the melody moves to the next note. All of these things make this tune particularly well suited to the banjo and the dobro, which helps to explain why 'Fireball Mail' is a favorite among many banjo and dobro players.