Bach copying from his brothers book which he 'borrowed'

Then, taking his pen and some manuscript music-paper with which he had provided himself, he began his task of copying out the pieces contained in the book.

An hour or more slipped away in this absorbing occupation, and it was not until the moon had shifted her position, so that her rays no longer afforded the necessary light, that Sebastian ceased to ply his pen. Then, having hidden the book away and removed all traces of his work, the now wearied little musician sought his pillow and fell fast asleep.