In this film, assumed lost, Mephistopheles shows Faust a "charming moving vision of Marguerite at spinning-wheel in the garden". This is Faust’s vision of his desire. Its emotional power, as the film describes, compels Faust to make the pact with Mephistopheles. The old Faust then, in a puff of smoke, becomes a handsome young man.

Satan conjures vision of girl, for whom old man signs pact and is made young.

Source: The British Film Catalogue

Faust discovered in his study. Mephistopheles appears in a cloud of smoke (fine effect), offers Faust renewal of youth if he will sign bond. As inducement shows him charming moving vision of Marguerite at spinning-wheel in the garden. Faust hesitates no longer; signs bond! Mephistopheles triumphantly waves drinking cup, causing it to emit a cloud of smoke, which falls around Faust as he changes to a handsome young man.

Source: Prestwich catalogue