A new compass indicates when the airplane is upside down

Title (Dublin Core): A new compass indicates when the airplane is upside down
Subject (Dublin Core): en Technology; en Airplanes and Zeppelins
Article Title and/or Image Caption (Dublin Core): It Tells the Aviator if He's Upside Down
Language (Dublin Core): eng
Temporal Coverage (Dublin Core): Interwar period
Date Issued (Dublin Core): 1919-05
Is Part Of (Dublin Core): Popular Science Monthly, v. 94, n. 5, 1919
pages (Bibliographic Ontology): 67
Rights (Dublin Core): Public domain (Google digitized)
Source (Dublin Core): Google Books
References (Dublin Core): New York City
Archived by (Dublin Core): Davide Donà; Marco Bortolami (editor)
Spatial Coverage (Dublin Core): United States of America