The Unknown Quantity
- Ár: 1919
- Land: United States of America
- Genre: Drama
- Stúdíó: Vitagraph Company of America
- Lykilorð: lost film
- Leikstjóri: Thomas R. Mills
- Leikarar: Corinne Griffith, Huntley Gordon, Harry Davenport, Jack McLean, Jack Ridgeway, F.R. Buckley
