Intriguingly, Hensel’s opening Adagio ma non troppo is not in a conventional first-movement sonata form at all but rather a lyrical fantasia on a small group of thematic ideas. Hensel’s opening idea, alluding to Mendelssohn’s overture Calm Sea and Prosperous Voyage, is reharmonised or reworked every time it appears. Only at the end, though, does it cadence to the tonic. Despite its apparently free, fantasia-like elaboration of material, there is nonetheless a persuasive logic to Hensel’s design, which can be brought out by applying the Henselian ‘schemata’ recently identified by Stephen Rodgers to the movement. Finally the chapter considers the hermeneutic potential of the movement’s references to the music of Hensel’s brother, returning to Cornelia Bartsch’s idea of ‘music as communication’.