Graphoplex Calcrude Oli Viscosity Slide Rule

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Country of manufacture: France,            Date of manufacture: ____
Overall length: 18.9 cm,          Width: 3.2 cm,           Weight: 38.7 gms
Materials: alll plastic
Cursor: 5.5 X 3.5 X 0.5 cms, parallelogram shaped; metal runners holding plastic lens; lines = one on front, plus diagonal line to use with nomogram on back of rule
Scales: 10, some specialized; nomogram on back
Front: 6 inches || B³, B² [ b², a, b ] B, L
Well: °F - °C conversion nomogram
Back: Viscosity nomograph relating Degrees Engler, Saybolt Universal, & Centistokes, at various temperatures.
Slide Back: °A.P.I., D
Gauge Marks: [C, C1, π, ρ_,,, ρ', ρ'' ]
Condition: C7 (Small chipout on upper left front of rule; otherwise, C3-C4 - very minimal to minimal signs of use)
Came with: Original leather pocket slipcase, labeled 'Calcrude', with Chevron logo

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