A note on public domain: The Dover Publication books are clipart and music that is copyright free. The "Seventy Scottish Songs" for example, has this notice in the first pages:
DOVER MUSICAL ARCHIVES
All the selections in this volume are in the public domain in the United States. They may be used in these original versions or may be adapted or modified and used for any purpose, private public, educational, or commercial. No permission, fee or royalty payment is required. The above does not apply in countries outside of the United States where copyright protection may exist.