Circular slide rule for air navigation computations, plastic made by J.B. Carroll Company, Chicago Circular slide rule for air navigation computations
1. Compilation drawing; 2. Enamel zinc plate; 3. Lithographic zinc plate; 4. Printed chart. All for Admiralty Chart 1446, Aberdeen Harbour 1. Compilation drawing; 2. Enamel zinc plate; 3. Lithographic zinc plate; 4. Printed chart for Admiralty Chart 1446
Artificial horizon (incomplete) by John Frederick Newman (I. Newman) Artificial horizon (incomplete) by John Frederick Newman (I. Newman)