This duet with Earl Hines is one of the high points of jazz recordings, anticipating elements of the music to come, even decades later. To understand this piece as improvised duet means to gain some awareness of how improvisation works. It is both a self-spur to greater achievement and a competition with others in the band - in this case only the duet partner. Improvisation is a way of composing on the spot, which means you have to know the music very well. Weather Bird was composed by King Oliver, with whom Armstrong recorded it first in 1923, a recording worth listening to for a sense of the leaps and bounds (they seem sometimes like literal leaps and bounds) Armstrong and Hines have taken with the music in only 5 years. You also have to know whoever you are improvising with extremely well - Louis and Oliver were masterful at improvising together, and from this recording you get the impression that both Armstrong and Hines are getting to know each other the way wrestlers or fencers do. The level of invention here is astounding.
Both musicians are young and at the top of their form, both are proud and independent, fully engaged in competition with the other. Each is trying to top the other, and in order to understand the other well enough to do so, each seems to learn from the other as the performance unfolds. This gives the piece something of the excitement of a competition, and contributes to the enormously effective concentration of energy and drive as it builds to a climax.
The form of the piece is sectional, which is the kind of form used for rags and marches. There are ten sections (lets call them choruses) in all: Introduction A B B A Interlude C C C Coda. Each of the sections is 16 measures long, the intro is 4, the coda is 12. There is an interlude of 4 measures between the second A and the first C chorus.
As the piece begins you can hear Earl Hines play a kind of stride rhythm - stride was a popular piano style of the day - but as the piece continues he moves further and further from the notion of his piano as a mere rhythm section for Louis’s trumpet solo. You will hear this as you listen to the first four sections, which have a sort of frame or mirror-like structure: the first A and the first B followed by the second B and the second A. In those repeat sections listen to how Hines pulls away from the dominant rhythm, setting his own pace and tempo.
In fact, throughout this piece both performers establish a unique - and very influential - approach to phrasing. Each plays “across the bar line,” that is, extending their phrases beyond where the bar (measure) would end, propelling them, pushing them out. Stanley Dance, in the notes to the Time-Life series, writes,
Hines and Armstrong were among the first jazz musicians to start playing across the bar line in this fashion. There is no feeling here of what might be called the typewriter approach, in which the players seem to be throwing the carriage back and starting afresh after each two bars.
4-bar Introduction 0 - 4
Louis Armstrong and Earl Hines set up the piece with a brief introduction. We will get used to hearing that final cadence (a cadence is a musical strain that comes to a close) throughout these choruses.
16-bar A Chorus 4 - 22
The pair gets off to a bouncy start, responding almost self-consciously to the music and to each other. Typically, the piano plays accompaniment and carries the rhythm, which Hines does, at least in the beginning. As the chorus progresses we hear him - actually, it takes some practice to listen, even to Earl Hines, when Louis is blowing away on top, but its worth doing - as he begins to pull away from the rhythmic norm, experimenting with various sorts of syncopations. (Syncopation means playing off the beat and is common in jazz.) Louis plays this chorus by experimenting, as it were, with dynamics, so that some parts are bold and brassy, others barely whispered.
16-bar B Chorus 23 - 41
In the B strain Hines continues his rhythmic independence, so that he both propels the music forward and creates interesting disruptions in the flow. You can sense how they are listening and responding to each other here.
16-bar B chorus 42 - 58
Hines takes a piano solo on the second B strain, playing stride for 4 bars then shifting gears with a tremolo, breaking into a new rhythm, a cascading arpeggio (an arpeggio is playing the notes of a chord one after another, going up or down the scale), and some rather fancy effects playing with the contrasts between bass (left hand) and treble (right hand) notes.
16-bar A Chorus 59 - 1:18
Armstrong returns to the duet with the reprise of the A strain. He plays the melody, then plays with the melody, and then just leaves it be and improvises, bringing a dramatic intensity to the high notes in bars 8-9 - at 1:07 - with a run of eighth notes at 1:08-9 (meaning there are 8 notes to the measure).
4-bar Interlude 1:19 - 1:22
After the ABBA part there is an interlude of 4 bars. James McCalla calls this “the polymetric section where you’ll lose the beat.” (McAlla, Jazz: A Listener’s Guide, p. 28). This free rhythm is highly advanced (meaning that it leads the way to the kind of jazz that will come later - fifteen or twenty years later - with be-bop and after). The rhythm also suggests what comes next in the piece itself, the three C choruses where the rhythm and the structure of the piece are gradually broken down.
16-bar C Chorus 1:23 - 1:41
The first C section is a piano solo of 16 bars. Note the right hand (treble noes) tremolo around 1:31-2, and closes with the by-now familiar cadential theme.
16-bar C Chorus 1:42 - 2:00
The second C section opens with a 2 bar break by Armstrong (1:42 - 4) , a duet of six bars, another 2-bar break by the trumpet (1:51-2), and another 6-bar duet, all done as if jousting on a high wire, calling and responding, until closing with that familiar cadence. The phrasing in this chorus is shorter than in earlier choruses
16-bar C Chorus 2:01 - 2:17
The third C section opens with a two bar piano break - at 2:01 - 2:02, reversing the order from the previous chorus - so that now the call-and-response is initiated by Earl Hines with Louis Armstrong in the responsive role. This is followed by a six bar duet, where Hines takes a most unusual break at 2:09 - 11. Armstrong plays around with the familiar cadential material, inaugurating a most unusual coda.
12-bar Coda 2:18 - 2:42
The coda to this piece is far more than just a traditional couple of bars that bring a song to a stomping closure. The trumpet and the piano trade 2 bars each twice, and then trade one bar each, twice. This trading twos and then trading ones (as it were) effectively pulls the piece away from the earlier rhythms. The song, as it were, breaks down, phrase by phrase. The number ends on one of Louis’s characteristic high C’s.