Bars 1-31: PERIOD 1 (ending in the Relative Minor)
Period 1 contains four Phrases. The figure which appears in the Treble in Phrases 1 and 3 is assigned to the Bass in Phrases 2 and 4, and the figure which appears in the Bass in Phrases 1 and 3 is assigned to the Treble in Phrases 2 and 4.
Bars 31-55: PERIOD 2 (Modulatory)
Period 2 is Modulatory until bar 47, when the Theme occurs in the Subdominant. Period 3 begins with the repetition of the Opening Subject. Bars 63-74, and bars 87-96 contain a melodic figure, employed in couplets, i.e., two bars are allotted to each feature.
Bars 55-104: PERIOD 3 (Repetition of Opening Subject and Coda)
Period 3, as it proceeds, is “fined down” more and more until the conclusion, by the additional employment of the Dominant Pedals (bars 63-73, 87-102) and Coda (bars 63-104.)
This Prelude is a remarkable instance of what is possible to do upon the same root principles of procedure as the Modern Sonata, but on totally different lines. From bars 1-31 the 1st Theme is used four times in different keys. In the Modulatory portion an entirely new Theme is started. The unusual length of the Coda is also very notable.
Bars 1-3: Subject in Treble [C# major]
Bars 3-5: Tonal Answer in Alto, with Counter-subject 1 in Treble [G# major]
Bars 5-7: Subject in Bass, with Counter-subject 2 in Treble and Counter-subject 1 in Alto.
Bars 7-10: Episode 1, modulating from C# major to G# major by descending sequence. (The Counter-subject 2 at its conclusion overlaps the commencement of this Episode.)
Bars 10-12: Answer in Treble, Counter-subject in Alto, Counter-subject 3 in Bass. (This latter melody is not used again until bars 51-53. [G# major]
Bars 12-14: Episode 2, modulating from G# major to D# minor. (Compare this with Episode 1 and notice the rolling semiquaver figure in the Bass now given to the Treble.)
Bars 14-16: Subject in Bass, Counter-subject 1 in Treble, Alto silent. [A# minor]
Bars 16-19: Episode 3, modulating from A# minor to E# minor. Materials are the same as previous Episodes, differently disposed.
Bars 19-21: Answer in Alto, Counter-subject 1 in Bass, Counter-subject 2 in Treble. [E# minor]
Bars 21-22: Codetta in all three parts, and close in E# minor
Bars 22-24: Episode 4, modulating from E# minor to G# major
Bars 24-26: Answer in Treble [G# major]
Bars 25-26: Counter-subject 1 in Bass, Counter-subject 2 in Alto
Bars 26-28: Subject in Alto, with Counter-subject 2 in Bass, and Counter-subject 1 in Treble [C# major]
Bars 28-42: Episode 5, modulating from C# major, through A# minor, F# major, D# minor, F# major, and back to C# major, by sequences, with frequent allusions to fragments of Subject.
Bars 42-44: Subject in Treble, with Counter-subject 1 in Bass [C# major]
Bars 44-46: Answer in Alto, Counter-subject 1 in Treble, Counter-subject 2 in Bass. [G# major]
Bars 46-48: Subject in Bass, Counter-subject 1 in Alto, Counter-subject 2 in Treble [C# major]
Bars 48-51: Episode 6, modulating from C# major, through F# major, D# minor, G# minor, and back to C# major.
Bars 51-53: Counter-subject 3 in Bass.
Bars 51-53: Subject in Treble, with Counter-subject 1 in Alto, and Counter-subject 3 in Bass. [C# major]
Bars 53-55: Coda, comprising a free version of Subject in Treble.
Exposition: Bars 1-7
Codetta: One (bar 21)
Coda: Bars 53-55